Glossary

FTP is the anchor for cycling plans. It defines your intensity zones (Z1 recovery, Z2 endurance, Z4 threshold, Z5 VO2max) from a single number. A 250 W FTP means you can sustain that power for about one hour before full exhaustion.

In TriPaced: In TriPaced, your FTP is auto-detected from your Strava activities (20-60 min max efforts). It feeds into every prescribed bike session and into your fitness metrics (CTL/ATL/TSB).

CSS is the swim equivalent of FTP. It represents the pace you can sustain over roughly 1,500 m without breaking. It anchors threshold intervals ("swim at CSS+2", "4×400 at CSS").

In TriPaced: In TriPaced, you set your CSS in Settings (s/100 m). Swim sessions use this to prescribe intervals at the right intensity, no manual math.

One hour at threshold = 100 TSS, by convention. A long Z2 ride may hit 150 TSS (duration), a short intense workout 80 TSS (intensity). TSS lets you compare the load of very different sessions.

In TriPaced: TriPaced shows prescribed TSS per session and actual TSS once completed. It feeds the CTL/ATL/TSB curves that drive your progression and injury risk.

CTL rises slowly with consistent training and drops during long downtimes. The higher it is, the more load you can absorb. A solid season takes a beginner from a 30-40 CTL toward 80-100 before an Ironman.

In TriPaced: TriPaced charts your CTL on the Fitness view. You see whether you're progressing, plateauing, or losing fitness. Plans target a steady rise, never abrupt (cap at +5-7 points per week).

ATL reacts fast: it climbs after a big week and falls after 2-3 recovery days. It's the snapshot indicator of how much fatigue you're piling on.

In TriPaced: In TriPaced, ATL is plotted alongside CTL. When ATL stays above CTL, TSB drops far negative and the app suggests easing off.

A TSB around 0 means you're absorbing your load without over-supercompensating or staying tired. Deep negative TSB (−20 or below) flags injury or staleness risk. Strongly positive TSB (+10 to +20) is the goal during taper before a race.

In TriPaced: TriPaced displays your live TSB. Plans automatically schedule recovery weeks (TSB rising) and race peaks (TSB target +5/+15 depending on distance).

Sweet spot offers the best stimulus-to-recovery ratio. Sweet spot sessions usually run 20 to 60 minutes (often in intervals) and don't crush you for days like pure threshold work.

In TriPaced: In TriPaced, sweet spot shows up in build weeks as an alternative to pure threshold. It accounts for a significant share of bike and run volume as a long race approaches.

At threshold, lactic acid builds up in the muscle faster than you can clear it. It's the line between hard-but-sustainable and effort that drops you within minutes. Threshold training pushes that line higher.

In TriPaced: TriPaced prescribes threshold work as short intervals (e.g., 4×8 min at threshold, 3 min recovery) during build blocks. Dose is calibrated to protect weekly recovery.

Taper sheds the fatigue stacked during build blocks while preserving fitness. Classic rule: 3 weeks of taper for an Ironman, about 10 days for a 70.3. Volume drops sharply but short intensity stays in to preserve neuromuscular adaptation.

In TriPaced: TriPaced computes the minimum taper duration for your A race (21 days Ironman, 10 days 70.3) and warns if the available window is too short. It keeps one activation session per discipline during taper so you don't "lose your legs".

Z2 sits around 60-75% of max HR or 65-75% of FTP. It's the prime intensity to build aerobic volume without paying a heavy recovery cost. Long weekend rides and runs (3-5h for an Ironman build) live in Z2 almost exclusively.

In TriPaced: In TriPaced, the Z2 share is calibrated to the polarized 80/20 model: ~80% of total time in Z1-Z2, ~20% high intensity (Z4+). This ratio maximises progression without overtraining.

On hilly or interval rides, average power under-estimates true difficulty (spikes cost disproportionately). NP applies a mathematical transform (30s moving average then ^4) that better reflects the "real" effort. A 200 W avg / 250 W NP ride is much harder than a 200 W avg / 205 W NP ride.

In TriPaced: TriPaced uses NP to compute the TSS of your rides (TSS = (duration × NP × IF) / (FTP × 3600) × 100). The further NP is above average power, the higher the recovery cost.

IF answers: "what fraction of my threshold did I ride at?". IF = 0.70 → easy endurance. IF = 0.85 → sustained sweet spot. IF = 0.95-1.00 → threshold work. IF > 1.05 over an hour = an FTP retest in disguise.

In TriPaced: TriPaced displays the target IF of every session. It's more telling than the zone alone: a long Z2 sits at IF=0.65, a short threshold piece at IF=0.95. You can see at a glance if a session is hard or recovery.

A brick simulates race-day T2 transition feel: heavy legs, cadence reset, pacing under post-bike load. It prepares you physically and mentally for what would catch you mid-race otherwise. Typical IM build volume: 4-5h Z2 bike + 30-45 min Z2 run.

In TriPaced: TriPaced auto-places 1-2 bricks per build block on Saturdays or Sundays depending on your availability. The brick's run leg is capped to avoid stacking too much impact on already-loaded legs.

Validated by Stephen Seiler (elite endurance research), polarized training avoids the "grey zone" Z3 (moderately hard) which costs recovery without delivering threshold or VO2max stimulus. The ratio is measured on weekly total time, not per session.

In TriPaced: TriPaced targets a polarized 80/20 weekly ratio. The app raises a "polarized warn LIT<60%" warning if you stack too much Z3 without enough easy Z1-Z2 around it. Documented physiology safeguard.

VO2max is the ceiling of your aerobic capacity. A beginner sits around 35-40 ml/kg/min, a trained age-group triathlete 55-65, world elite 75-85. Genetics and training contribute equally: you can gain 10-20% over your starting value with specific work across 1-2 seasons.

In TriPaced: TriPaced prescribes short, intense VO2max sessions (3-5 min Z5 per block) during build phases. Not during taper (Friel ch.13: VO2max intervals are swapped for shorter Z3-Z4 activation sessions there).

RPE complements objective metrics (HR, power, pace). On certain days (short sleep, stress, weather) a struggling Z2 session might feel like RPE 6 when you expected 3. Tracking RPE catches early fatigue before it shows on Banister curves.

In TriPaced: TriPaced lets you log RPE after each completed session. Eventually (V2 advanced weekly validation), the system will cross RPE with TSS to flag early overload (normal TSS + high RPE = a watch signal).

Running, a healthy target cadence sits between 170 and 185 spm: too low amplifies ground impact and injury risk, too high wastes energy. Cycling, 80-95 rpm covers most intensities: lower taxes the legs (pure force), higher loads the cardio-vascular system.

In TriPaced: TriPaced shows the recommended target cadence in every run and bike session detail. It adapts to intensity (e.g., Z2 bike cadence runs lower than Z4).

Periodisation organises load over time to peak on race day. Each phase has its role: base builds aerobic volume, build introduces race-specific intensity, peak sharpens energy systems, taper sheds fatigue. The ratio between phases depends on athlete experience and target distance.

In TriPaced: TriPaced generates an automatic periodisation tailored to your A race (weeks available, archetype). Friel safeguard: 80% linear progression, 20% planned step-back (recovery weeks every 3-4 blocks).

Z1 sits around 55-75% of FTP on the bike, or < 80% of CSS in the swim. It's used for recovery jogs, cool-downs and easy mobility days. No meaningful aerobic stimulus : just blood flow and movement quality.

In TriPaced: In TriPaced, Z1 mostly shows up on recovery weeks and after hard sessions. It can feel close to walking pace : that's intentional, the goal is zero added fatigue.

Z3 sits between Z2 (~76-90% FTP) and threshold (~91-105%). Breathing picks up, full sentences become uncomfortable. Living there too often piles up fatigue without delivering the threshold benefit. It's the zone polarized plans aim to skip.

In TriPaced: In TriPaced, Z3 only shows up in specific blocks (progressive long, brick, short sweetspot). If you drift into Z3 on a Z2 session, the post-session analysis flags it.

Swimmers typically use Z1 (recovery, > CSS+10 s/100 m), Z2 (endurance, CSS+5 to +10), Z3 (tempo, CSS+2 to +5), Z4 (threshold, CSS-2 to CSS+2), Z5 (VO2max, < CSS-3). Everything anchors on CSS : no lactate testing needed.

In TriPaced: In TriPaced, every prescribed swim interval shows an absolute pace target (s/100 m), not a zone tag: you read "1:35 / 100" directly : the app already converted from your CSS.

A 10 mm drop (classic) lifts the heel, easing the calf and Achilles but encouraging a heel strike. A 0-4 mm drop ("minimalist") spreads load better but heavily loads the calf : transition progressively over several weeks.

In TriPaced: TriPaced doesn't prescribe a brand or specific drop. But if you switch drops between blocks, log it as a session note: an Achilles flare-up the following week is rarely a coincidence.

On a marathon or Ironman, starting 5-10% below target pace preserves glycogen and form. The second half then becomes reachable without blowing up. Starting too fast ("positive split") typically costs 10-30 min in a late-race collapse.

In TriPaced: TriPaced won't push aggressive splitting if you lack the base. But on prescribed long sessions, the last 30 min can be tagged "progressive" : you learn to execute a negative split before race day.

Three big differences from pool swimming: SIGHTING (every 6-10 strokes to hold the line), CONDITIONS (chop, current, water temperature, wetsuit) and PACK START (contact, surges). 70% of Ironman DNFs happen in the swim : usually because one of these three was underprepared.

In TriPaced: TriPaced doesn't yet generate dedicated open water sessions (V2). In the meantime, add 2-3 real open water swims in the last 8 weeks before the A race and log them manually as "Z2 endurance".

On the bike in long-distance triathlon (Ironman, 70.3) drafting is FORBIDDEN: 12 m gap rule, 25 s overtake window, otherwise penalty. In the swim however it's ALLOWED and essential: sitting on someone's feet or hip at similar pace saves watts and helps sighting. On the run it exists (strong headwind) but the effect is smaller.

In TriPaced: TriPaced doesn't optimize drafting tactics (it's tactical, not physiological). Worth remembering: on the 70.3/IM, mentally accept the "solo rider" mindset from sign-up, and plan ahead if you end up in a pack (penalty = 5-10 min).

At an Ironman or 70.3, the organization mandates labeled bags: "bike gear bag" (helmet, glasses, bike nutrition), "run gear bag" (shoes, cap, gels), sometimes "street wear bag" (post-race clothes). Each bag must be self-sufficient : no trips back to the car.

In TriPaced: TriPaced doesn't yet ship a dropbag checklist (V2). Worth doing for your first long-distance race: build the list two weeks out, duplicate critical items (glasses, gels), and open the bike bag the evening before to mentally rehearse.

After 30-90 min horizontal, the vestibular system and venous return need tens of seconds to readjust to upright. Result: dizziness, wobbly legs, sometimes nausea. It's NORMAL and short-lived : sprinting out of the water is counter-productive.

In TriPaced: TriPaced doesn't prescribe transitions explicitly, but the first 30 s of T1 should be deliberately calm: breathe, walk steadily, focus on what comes next. You make up 5-10 s in transition; you lose minutes from a cardiac panic.

Adaptation principle: a stimulus beyond habit + sufficient rest = supercompensation (fitness goes up). Too much overload without the off-load = overtraining (fitness drops, chronic fatigue). The classic ratio is 3 progressive weeks then 1 recovery week (3:1).

In TriPaced: In TriPaced, overload is planned into BUILD and PEAK blocks; the RECOVERY week that follows is not optional. If you systematically skip the off-load week, the engine sees it in the ATL curve and warns you in post-session analysis.

Eric Banister proposed in 1975 a model where each session leaves two imprints: a long-decay one (fitness) and a short-decay one (fatigue). Today's freshness = fitness − fatigue. It's the foundation of every modern tool (TrainingPeaks, intervals.icu, TriPaced) using CTL, ATL, TSB.

In TriPaced: TriPaced reimplements Banister from your actual Strava activities, not an estimate. The initial seed (before your first imported activity) starts from a conservative value tied to your declared archetype.

A 70 kg cyclist with a 280 W FTP has a 4.0 W/kg ratio. That ratio : not raw watts : determines climbing speed (> 4 W/kg = good climber, > 5 W/kg = amateur elite). In long-distance triathlon, where climbs are long and moderate, a ratio of 2.8-3.5 W/kg covers the vast majority of competitive athletes.

In TriPaced: In TriPaced, W/kg is shown in your fitness profile (FTP ÷ body weight from Settings). The engine uses it to calibrate target TSS for long bike sessions based on the climbing profile declared in your race settings.

Above Z5 (VO2max), you enter anaerobic capacity: glycogen burns without oxygen, lactate climbs fast. Efforts last rarely beyond 3-5 minutes before forced stop. In long-distance triathlon, Z6 is almost never prescribed : but understanding it helps avoid the trap of going out too hard on the bike.

In TriPaced: In TriPaced, Z6 doesn't appear in any standard IM or 70.3 plan. If a session shows 'Z6', it's a warning flag: the prescribed intensity is likely too high or you entered a FTP that is too low.

Z7 is absolute sprint: under 30 seconds, often < 10 s. Power exceeds 200-300% of FTP. It's no longer about aerobic capacity but about maximal fast-twitch fiber recruitment. In long-distance triathlon, Z7 is theoretically absent from the plan. In road or track cycling, it's the territory of finishing sprints.

In TriPaced: In TriPaced, Z7 is not prescribed in long-distance triathlon plans. If Z7 power shows up in post-session analysis, it's either an overly aggressive hill start or a spontaneous end-of-ride sprint : interesting for neuromuscular activation, but don't repeat it mid-BUILD block.

Aerobic adaptations (VO2max, FTP, running economy) begin declining in 10-14 days without training, with a measurable 5-10% VO2max drop over 4 weeks. Muscle mass is more resilient (weeks to months). The good news: muscle 'remembers' : after a 4-week break, a trained athlete rebounds in roughly half the time it took to build the initial fitness.

In TriPaced: In TriPaced, a gap in Strava activity naturally pulls CTL down. If you return after 2+ weeks off, the engine suggests a 'Progressive Return' block at reduced intensity to prevent comeback injury : you'll want to do more than prescribed; resist the urge.

In an IM triathlon, glycogen stores are insufficient for the 8-14 h race without external fueling. Target 60-90 g of carbohydrates per hour (mixed carbs: glucose + fructose 2:1 for max absorption), 600-800 ml of water per hour, and sodium (400-800 mg/h depending on sweat rate). One gel = 20-25 g of carbs, spaced every 20-30 min based on heat and effort.

In TriPaced: In TriPaced, race nutrition isn't yet dynamically prescribed (V2 feature). But long sessions (>2 h bike, >1 h 30 run) include a nutrition reminder in the session description, based on your target distance and the heat window of your race.

At low intensity (Z1/Z2), lactate is cleared as fast as it's produced. Past the first threshold (LT1, the lower boundary of Z3), it begins to accumulate slowly. At the second threshold (LT2, equivalent to FTP on the bike), accumulation accelerates and the effort can't be sustained long. Pushing LT1 upward through long Z2 sessions is the main goal of aerobic base training.

In TriPaced: In TriPaced, intensity zones are computed from FTP (bike) and CSS (swim), which roughly correspond to LT2. Long Z2 sessions aim to push LT1 higher, building your aerobic base.

FTHR is the heart-rate equivalent of FTP (power). It lets you define intensity zones in beats per minute when you don't have a power meter. For example, a FTHR of 165 bpm puts your Z2 around 130-145 bpm. Heart rate is influenced by heat, fatigue, and dehydration, making it less stable than power in the short term.

In TriPaced: In TriPaced, FTP (power) is the main reference for bike zones. FTHR serves as a complementary marker to calibrate run and swim sessions when no power measurement is available.

A healthy heart doesn't tick like a metronome: the interval between beats varies slightly. High HRV (highly variable intervals) signals a rested autonomic nervous system and good recovery. Low HRV flags fatigue, stress, or overload. Best measured each morning at rest, fasted, with the same protocol daily so the trend is readable.

In TriPaced: In TriPaced, HRV is not yet natively integrated (V2 feature). Recovery sessions are scheduled via TSB (form) computed from CTL and ATL based on your Strava activities.

Supercompensation is the core mechanism of endurance progression: you load (TSB drops), you recover (TSB rises), and if the timing is right, you come back stronger than before. Too little recovery and you stay fatigued. Too much and the benefit is lost. Three-week load plus one-week taper cycles exploit this mechanism repeatedly to build long-term fitness (CTL).

In TriPaced: In TriPaced, the plan's periodization (load weeks + rest week) is designed to trigger supercompensation at the right time. A positive TSB during race week reflects exactly this rebound: you arrive rested but not detrained.

Pace is expressed as minutes per kilometre (e.g. 5:00 /km). It depends on your maximal aerobic speed (MAS), lactate threshold, and daily freshness. Plans distinguish Z2 pace (aerobic base, ~70-75 % max HR), threshold pace (near 10 km effort, ~85 % max HR), Z5 pace (VO2max intervals), marathon pace, and Ironman pace (slightly slower than marathon to preserve reserves).

In TriPaced: In TriPaced, prescribed run sessions target an intensity zone (Z2, threshold, VO2) rather than a fixed pace, because pace depends on your daily form. Session descriptions translate the zone into an indicative pace range computed from your detected threshold.

Volume is the easiest training variable to manipulate: add kilometres or hours. On an Ironman plan, weekly volume typically ranges from 6-8 h in easy base weeks to 14-18 h at peak load for advanced athletes. Too much volume without enough intensity wastes time. Too much intensity without enough volume creates an aerobic base deficit. Managing the volume-to-intensity ratio is what sets a structured plan apart from free training.

In TriPaced: In TriPaced, weekly volume is automatically adjusted based on your availability (slots set in Settings), your preparation phase, and your target distance. CTL (long-term fitness) is the direct result of sustained volume week after week.

Aerobic base is built in Z2: long sessions at moderate intensity, conversational pace, stable HR. This phase increases mitochondrial density, improves fat oxidation (better energy efficiency over long distances), and raises the LT1 lactate threshold. In Ironman triathlon, a solid base (CTL 60-80) is essential before adding high-intensity volume, or injury and overtraining risk rises sharply.

In TriPaced: In TriPaced, the Base phase of your plan concentrates most volume in Z2 (swim, bike, long run). This is also the phase where CTL rises fastest. Z4/Z5 sessions remain a minority during this phase to protect long-term progression.

T1 (swim to bike): wetsuit off, helmet on, shoes on. T2 (bike to run): dismount, helmet off, running shoes on. Transitions are part of the official clock. On an Ironman, a combined T1 + T2 of 5-7 min is solid for amateurs; pros go through in 2-3 min. Practising transitions in training (ending a bike session and running immediately) builds automatism and cuts lost time.

In TriPaced: In TriPaced, brick sessions (bike followed immediately by a run) replicate T2 conditions. Transition time isn't prescribed in the plan, but your race A or B schedule includes target time windows per discipline.

Race cramps have two main causes: neuromuscular fatigue (muscles pushed beyond their capacity) and electrolyte deficit (sodium, potassium, magnesium) worsened by sweat losses. In Ironman, they typically strike in the last two-thirds of the marathon. Prevention involves adequate training at target volume, a rigorous fuelling strategy, and heat acclimatisation if racing in hot conditions.

In TriPaced: In TriPaced, long sessions (3-5 h bike, 25-35 km long run) prepare the neuromuscular system for sustained effort. Long-session descriptions prompt you to practise the fuelling strategy planned for your target race.

Heat raises heart rate at a given intensity (cardiac drift), increases fluid losses (up to 2 L/h on the bike), and accelerates glycogen depletion. Above 25-28 °C, Ironman performance drops measurably for most athletes. Key strategies: 10-14 day acclimatisation beforehand (training sheltered or in a warm place), active cooling (ice in pockets, sponges at aid stations), proactive hydration (drink before feeling thirsty), deliberate pace reduction of 10-20 s/km.

In TriPaced: In TriPaced, long run sessions include an expected heat indicator if your race's weather window is known. The description reminds you to adjust your target pace when forecast temperature exceeds 25 °C, to preserve the target TSS without going out too hard.

Zone 4 corresponds to an effort intensity around the lactate threshold : the point at which lactate production exceeds the body's ability to clear it. In cycling, this is typically 90-105% of FTP; in running, it is roughly threshold pace. Zone 4 sessions last 20-40 minutes continuously, or break into 8-15 minute intervals. It is the most specific training zone for improving threshold power or pace.

In TriPaced: In TriPaced, Zone 4 sessions appear in BUILD and PEAK phases : typically 'threshold pace' or 'threshold intervals' of 3×12 min. The plan avoids Zone 4 in recovery weeks and never stacks two threshold sessions within 72 hours.

Zone 5 pushes the cardiorespiratory system to its limit, targeting VO2max : the maximal oxygen uptake. In cycling, this corresponds to 106-120% of FTP (maximal intervals of 3-6 minutes). In running, it is around 5K race pace. These sessions develop the aerobic engine deeply, but require full recovery (48-72h) and should not be done too frequently : once per week in the BUILD phase is typically sufficient.

In TriPaced: In TriPaced, Zone 5 sessions (e.g. 5×3 min at maximal effort, 3 min recovery) only appear in BUILD and PEAK phases for ADVANCED profiles. For BEGINNER and INTERMEDIATE profiles, Zone 4 volume takes priority. The plan never stacks Zone 5 and Zone 4 on the same day.

Tempo training sits between aerobic base (Z2) and threshold (Z4) : an intensity that hurts but is sustainable for 40-90 minutes. In cycling, 'sweet spot' often refers to the 88-95% FTP range: excellent aerobic benefit-to-effort ratio. In running, tempo pace is often described as 'comfortably hard' : you can speak, but only in short sentences. It is the ideal zone for building aerobic endurance without repeated threshold exposure.

In TriPaced: In TriPaced, tempo sessions appear as 'threshold pace endurance' or 'Zone 3 work'. The planner uses them in BASE and early BUILD phases to build aerobic capacity before introducing true threshold (Zone 4) work.

Pacing is the art of distributing energy optimally over the duration of an effort. Starting the Ironman bike too fast leads to a run collapse; being too conservative leaves time on the table. The optimal strategy for Ironman is typically 'even split' (steady pace) or a slight negative split (slight acceleration in the second half of the run). In swimming, pacing depends on start position; on the bike, it is controlled via normalized power (NP) or heart rate.

In TriPaced: In TriPaced, the plan indicates target pace and HR zone for each race segment. Bike pacing advice (target IF, target NP) is integrated into simulated competition sessions.

An energy gel is a semi-liquid preparation rich in fast-absorbing carbohydrates (maltodextrin, fructose, glucose) packaged in a 30-40 g sachet. The goal is to deliver 22-25 g of carbohydrates without chewing or drinking large amounts. In Ironman, the target is 60-90 g of carbohydrates per hour (up to 120 g/h for athletes trained for high absorption). Gels alone rarely suffice: they need to be alternated with solid food and hydration. Testing in training is mandatory : some gels cause digestive issues.

In TriPaced: In TriPaced, long sessions (>1h30) include a nutrition note indicating when to introduce gels. The fueling strategy is personalized based on the estimated duration of each race segment.

Electrolytes are charged ions that play a key role in muscle contraction, nerve transmission, and fluid balance. Sodium is most important in endurance: excessive loss (>1 g/h in heat) causes hyponatremia and cramps. In Ironman, replacing 500-1000 mg of sodium per hour via isotonic drinks, salt capsules, or electrolyte gels is standard practice. Potassium (bananas, sports drinks) and magnesium round out the strategy. Hydration alone without electrolytes in long-distance racing can be dangerous.

In TriPaced: In TriPaced, hydration advice integrates electrolytes for sessions over 2 hours. The strategy is adapted to the estimated heat on race day.

Overtraining syndrome (OTS) occurs when the load-recovery balance is chronically disrupted. Unlike non-functional overreaching (NFO, reversible in 2-4 weeks), OTS requires months of rest. Symptoms: unexplained performance drop, persistent fatigue, sleep disturbances, irritability, chronically low HRV, reduced appetite. It differs from overload (planned overloading) which is intentional and followed by planned recovery. Prevention: respect recovery weeks, monitor HRV, adjust volume at the first signs.

In TriPaced: In TriPaced, recovery weeks (roughly 1 in 4) and TSB management aim to prevent overtraining. The engine's physio guard blocks overloads that exceed physiological ramp rate limits.

Aerobic decoupling (Pa:Hr on Garmin) measures the degradation of cardiorespiratory efficiency during long efforts. It compares the pace/HR ratio of the first half of a session to the second: decoupling <5% indicates good aerobic fitness; >8% signals the intensity was too high or heat/dehydration disrupted thermoregulation. It is an objective marker for improving aerobic base: high decoupling means the long run intensity was too high. The goal is to stay under 5% during Zone 2 long sessions.

In TriPaced: In TriPaced, long Zone 2 sessions are planned so decoupling stays <5-7%. On Strava returns, the app identifies sessions with marked cardiac drift and can adjust the recommended intensity for the next session.

Aerodynamics accounts for 70-90% of total resistance on the bike above 35 km/h. The aero position (elbows on aero bars, horizontal torso, low head) can save 10-20 minutes on an Ironman compared to an upright position. Key parameters: aero bar height and width, drop (saddle-to-bar height difference), saddle height, torso angle. A professional fitting is recommended before extended aero training periods. Caution: too aggressive a position hurts pedaling efficiency and the run off the bike.

In TriPaced: In TriPaced, long bike sessions include progressive aero position blocks to accustom the back and hips. The app indicates recommended aero duration based on the training phase.

The Build phase follows the Base phase in classic Friel periodization. Its goal is to increase intensity specific to the target race : more threshold work (Z4), VO2max intervals (Z5), and race-pace simulations. Typical duration is 8-12 weeks before taper. It is the most demanding phase: volume remains high AND intensity increases. It ends with a recovery week before entering the Peak or Taper phase. For Ironman, Build includes long sessions at IM race pace (85-90% of race tempo).

In TriPaced: In TriPaced, the Build phase appears in the plan timeline between Base and Peak. Zone 4 sessions progressively increase (controlled ramp rate) and long bike sessions include blocks at IM intensity. The planner guarantees no Build week exceeds physiological ramp rate limits.

An interval session alternates intense efforts with recovery periods. Target intensity can be Z4 threshold (e.g. 4×10 min), Z5 VO2max (e.g. 5×3 min), or Z6 anaerobic (e.g. 8×30 s). The work-to-rest ratio varies by goal: closer to 1:1 means more VO2max-specific work. In long-distance triathlon, intervals are mostly sub-threshold to avoid excessive recovery debt.

In TriPaced: In TriPaced, interval sessions appear during Build and Peak phases based on your FTP and CSS. The planner adjusts reps and recovery duration to stay within your target weekly TSS.

The aerobic threshold (SV1 / LT1) marks the lower boundary of fundamental endurance. Below it, the body runs primarily on fat and lactate stays near resting levels. Above it, carbs become the dominant fuel and lactate starts to accumulate. For an Ironman triathlete, SV1 is typically around 70-77% of max HR or ~55-65% of FTP. Most volume training should stay below this threshold to promote aerobic adaptation without accumulating fatigue.

In TriPaced: In TriPaced, the aerobic threshold is the upper boundary of Z2. Long aerobic base sessions are calibrated to stay below SV1, maximising adaptation with faster recovery.

Glycogen is polymerised glucose stored mainly in muscles (~400-500 g) and liver (~80-100 g), representing about 1,600-2,400 kcal total : enough for ~90-120 min of hard effort. Beyond that, the 'marathon wall' or 'bonk' occurs if exogenous carbohydrate intake is insufficient. The higher the intensity, the faster glycogen depletion. In Ironman (10-12 h), in-race fuelling is critical to maintain stores.

In TriPaced: In TriPaced, built-in nutrition tips account for session duration and intensity to help you avoid glycogen depletion. Race nutrition tips explain in-race refuelling strategies for Ironman.

A drill breaks the full movement into sub-components to work them in isolation. Classic swim drills include catch-up (extended front arm), fingertip drag (high elbow awareness), and side-kick drills. Running drills: high knees, butt kicks, high skips. Cycling: single-leg pedalling circles. Drills don't replace full swimming or running but build new neuromuscular patterns that integrate gradually.

In TriPaced: In TriPaced, technique sessions include prescribed drill blocks at the start of swim sessions or run warm-ups. They are included in session TSS with a low intensity factor.

Running economy measures how much oxygen you consume to cover 1 km at a target pace. Two runners with identical VO2max can perform very differently if one has better economy. Key improvements come from a higher cadence (~175-185 spm), tendon stiffness (plyometrics), varied-surface running, and functional strength work. In triathlon, running economy is especially important as the run leg starts on legs already fatigued from swimming and cycling.

In TriPaced: In TriPaced, functional strength blocks and high-cadence sessions prescribed in the plan aim to improve your running economy, optimising your final run speed in the Ironman.

Compression garments exert graduated mechanical pressure from ankle toward knee (or wrist toward shoulder). This promotes venous return, reduces muscle micro-vibration during effort and may limit post-exercise soreness. Performance benefits are debated (likely placebo during competition), but recovery benefits (post-effort wear 2-3 h) are better documented. In racing, compression socks also help prevent cramping over long distances.

In TriPaced: In TriPaced, recovery tips include wearing compression socks after long sessions. Race equipment (wetsuit, compression socks) is covered in gear preparation tips.

The bonk (or 'hunger knock') occurs when muscle and liver glycogen stores are exhausted. The brain, dependent on glucose, sends distress signals: dizziness, confusion, leaden legs, urge to stop. The primary cause is insufficient carbohydrate intake during effort (especially in racing). Full recovery takes 15-30 min after ingesting fast-acting carbs. In Ironman, targeting 60-90 g of carbs per hour from the bike leg (maintained through the run) prevents complete depletion. Poor pacing at the start (too fast = accelerated glycogen combustion) is the number-one cause.

In TriPaced: In TriPaced, built-in nutrition tips flag bonk risk for sessions over 90 min. Race nutrition tips outline the Ironman fuelling strategy to maintain steady carbohydrate intake across the full 10-12 h.

At altitude, partial O2 pressure drops, forcing the body to produce more erythropoietin (endogenous EPO) to compensate. After 2-3 weeks at elevation, red blood cell mass increases, improving oxygen transport. Benefits persist 4-6 weeks after return. The classic protocol is 'live high / train low' (LHTH or LHTL): stay at 2,000-2,500 m but do intense training at lower elevation (where O2 is sufficient for target intensities). Altitude only benefits performance if intensity and volume are not reduced too much.

In TriPaced: In TriPaced, if you mark an altitude camp in your calendar, the planner adjusts prescribed intensities to account for reduced capacity at elevation (~5% less per 1,000 m) and schedules a recovery block on return.

CdA (drag coefficient × frontal area, in m²) quantifies the aerodynamic drag of the cyclist+bike system. In Ironman, at 40 km/h, 70-85% of power is spent against wind. A typical CdA in aero position on a triathlon bike is 0.20-0.25 m², versus 0.35-0.40 m² upright. Key levers: bike position (aero bars, torso tilt), TT helmet, smooth skinsuit, covered wheels. Reducing CdA by 0.01 m² is worth approximately +15 W effective power at 40 km/h.

In TriPaced: In TriPaced, cycling tips include practical advice on aero position and equipment to reduce your CdA without sacrificing comfort : especially critical across the 180 km Ironman bike leg.

Active recovery means performing very low-intensity activity (pure Z1: 50-60% max HR) after a high-load day or race. It speeds residual lactate clearance, reduces soreness through increased blood flow, and maintains muscle tone without compromising adaptation. Typical duration: 20-40 min. Examples: very easy cycling (50-60 W), slow effortless swimming, very relaxed jogging <6 min/km. It does not replace complete rest; over a 4-5 day recovery block, alternating 1 day off / 1 day active recovery is optimal.

In TriPaced: In TriPaced, active recovery sessions are automatically scheduled after high-intensity blocks or races. They are short, clearly labelled 'Recovery', and calibrated to strict Z1 so they don't increase weekly TSS.

Resting HR is measured lying down in the morning before getting up. It decreases with aerobic training (trained athletes often reach 40-55 bpm). An RHR 5-10 bpm above your baseline often signals accumulated fatigue, early illness, or poor sleep. Tracked daily, it is a reliable recovery barometer.

In TriPaced: In TriPaced, you can enter your resting HR in Settings. It refines HR zones via the Karvonen method (HR reserve = max HR − resting HR), producing more personalised zones than simple % max HR.

VMA is the running equivalent of FTP on the bike. It is measured by an incremental test (Cooper, Vam-Eval) or estimated from a 3-6 min maximal effort. Short intervals (30/30, 1 min/1 min) are prescribed at 100-110% vVO2max to stimulate VO2max. Typically 14-22 km/h depending on level.

In TriPaced: In TriPaced, VMA is estimated from your 3-10 min maximal run efforts imported via Strava. It calibrates the most intense run interval sessions and defines your run zones by speed.

HR Reserve = max HR − resting HR. The Karvonen method derives intensity zones across this range: Z1 at 50-60% HRR, Z2 at 60-70%, Z4 at 80-90%. It is more accurate than raw % max HR because it accounts for fitness level. An athlete with a resting HR of 45 bpm and a max HR of 185 bpm has an HRR of 140 bpm : a wider usable range.

In TriPaced: In TriPaced, if you enter both max HR and resting HR in Settings, zones are computed via Karvonen. Without resting HR, the default method (direct % max HR) is used.

The long session is the cornerstone of any long-distance plan. On the run it progresses from 1h30 to 3h depending on the phase; on the bike, from 3h to 6h in base. Performed at Z2 (60-75% max HR) to maximise mitochondrial adaptations and fat utilisation. Going too fast turns it into a threshold effort and compromises recovery. The rule: if you can hold a normal conversation, the pace is right.

In TriPaced: In TriPaced, the weekly long session is automatically scheduled on weekends (long bike Saturday, long run Sunday in general). It often accounts for 30-40% of the weekly TSS and drives the CTL ramp.

The 10% rule states not to increase total volume by more than 10% per week. In practice, a 3:1 block structure (3 loading weeks + 1 recovery week) is more robust than linear progression. Too-fast load ramp (ATL growing >5 TSS/day/week for 3 weeks) is the leading cause of overuse injury. Ideal ramp rate in Ironman prep: 3-5% CTL/week during build phase.

In TriPaced: In TriPaced, the load ramp is managed by the periodisation algorithm. The rate is adapted to your training window and reference TSS. A warning displays if ATL grows too fast (injury risk).

Fasted training means exercising in the morning without breakfast, or after a low-carb evening, to force the body to prioritise fat oxidation. Reserved for short Z1-Z2 sessions under 90 minutes: beyond that or at high intensity, performance drops and muscle catabolism rises. Effective in base phase to improve fat utilisation at Ironman pace.

In TriPaced: In TriPaced, some short Z1-Z2 sessions are tagged 'fasted OK' in session notes. A long session or interval workout will never be planned fasted: the plan flags this explicitly.

Strides are 80-100 m or 20-30 s accelerations at 85-90% vVO2max, with 60-90 s walk recovery. Their role is to stimulate the neuromuscular system, maintain running mechanics, and lower perceived effort at fast paces. They do not fatigue (negligible TSS) but noticeably improve coordination at high cadence. Recommended frequency: 4-6 strides twice a week.

In TriPaced: In TriPaced, strides sometimes appear as an option at the end of easy run sessions (label 'Strides × 4-6'). They are not counted toward session TSS but are logged in the session notes for tracking.

In Ironman, aid stations are spaced every 20 km on the bike and every 2-3 km on the run. Golden rule: never try anything for the first time on race day. Best practice: take gel + water (not gel + sports drink together, to avoid osmolar overload), alternate gel and bar every 20-25 min on the bike, switch to soft solids on the marathon if stomach allows.

In TriPaced: In TriPaced, the recommended nutrition strategy appears in the Race A/B session sheet based on your estimated segment durations. It reminds you of target carbohydrate quantities (60-90 g/h) and absorption windows by intensity.

In non-drafting long-distance triathlon, the penalty tent punishes bike drafting (staying in another competitor's draft within 12 m in IM, 10 m in 70.3), unsafe riding, or non-compliant equipment. A referee issues a penalty card; the athlete must report to the tent and stay for 4 minutes (full IM) or 5 minutes (70.3). Failing to report = disqualification (DSQ).

In TriPaced: In TriPaced, the Race A sheet reminds you of drafting distance rules (12 m in IM, 10 m in 70.3) and the usual location of the penalty tent on the bike course, so you don't miss it under race stress.

Three formats exist: (1) mass start : everyone together, the most physical; (2) wave start : groups of 50-100 athletes launched 2-3 min apart by age group or estimated finish time; (3) rolling start : self-seeding, athletes enter the water individually by declared swim time, seconds apart. Ironman Kona has used rolling starts since 2013. Local races often alternate between mass and wave starts.

In TriPaced: In TriPaced, the start format for your Race A is shown in the race sheet (when known). It informs your positioning strategy at the start and management of the first 400 m of the swim.

HRmax is individual and declines with age (rough formula: 220 − age, but with ±10-15 bpm variability). Reliable measurement methods: (1) field test : progressively harder sprints on a hill at the end of a hard session, last sprint all-out; (2) 5-10 min maximal time trial : the last 30 seconds usually reveal the peak. HRmax is not a fitness indicator: it's genetic and stable year to year. An HRmax of 175 is not 'better' than 165 : only the distribution of zones matters.

In TriPaced: In TriPaced, HRmax is entered during onboarding (or in Settings). It calibrates all your HR zones (Z1 to Z5) and your heart rate reserve for each discipline. If your actual HRmax differs from the default estimate, update it : the error propagates to all prescribed intensities.

VT1 (first ventilatory threshold) corresponds to the onset of significant lactate accumulation: ventilation accelerates, conversation becomes difficult : the 'talk test' reveals VT1: you can still say 3-4 words per exhalation. VT2 (second ventilatory threshold, respiratory compensation point) marks CO₂ rising sharply: hyperventilation, no conversation possible. Between VT1 and VT2 = the 'threshold' zone (tempo/sweetspot). Ventilatory and lactate thresholds are close but not identical: gas analysis is lab-based, the talk test is field-based.

In TriPaced: In TriPaced, VT1 corresponds to the upper boundary of Z2 (moderate aerobic) and VT2 to the upper boundary of Z4 (threshold). These thresholds are calculated from your FTP and HRmax. Most long sessions in base phase target Z2 : you should be able to speak in full sentences.

Peripheral fatigue originates in the muscle: glycogen depletion, acidosis, myofibrillar damage. It resolves in 24-72h depending on intensity. Central fatigue originates in the nervous system: reduced motor drive, altered perception of effort (RPE). It's more insidious : the athlete 'feels fine' but maximal power or pace is depressed. In Ironman, both accumulate simultaneously. The day after a long brick or a 5h+ fasted ride, central fatigue can persist even if the legs feel light: a frequent trap during high training load periods.

In TriPaced: In TriPaced, the Load & Form block (CTL/ATL/TSB) captures overall fatigue but doesn't distinguish central from peripheral. If you feel mentally depleted despite a neutral TSB, it's often central fatigue: the planner may then suggest a short or active session rather than a long endurance effort.

After 5+ hours of cycling in an Ironman, the first minutes of running show characteristic 'sea legs': legs feel heavy, stride shortens, the neuromuscular system struggles to switch from cycling posture to running form. Specific 'run off the bike' (ROB) training prepares for this transition: chaining 15-30 min of running immediately after a cycling session, several times per week during the build phase. Target adaptations: slow-fiber recruitment under post-bike fatigue, maintained running economy, ability to hold target marathon pace despite the muscular shift.

In TriPaced: In TriPaced, brick sessions are flagged with the note 'Chain a 15-30 min run immediately after.' During Ironman build phase, the planner incorporates 1-2 short ROBs per week, calibrated to avoid interfering with recovery between long sessions.

Joe Friel distinguishes two types: the A session (the week's most important session, to be protected at all costs : typically the long weekend ride or threshold interval) and the B session (important but sacrificeable if fatigue or schedule conflicts arise). All other sessions are recovery or complementary volume. This hierarchy allows the athlete to prioritize when time is short: one quality A session with two skipped Bs beats a complete but rushed week. In peak phase, athletes typically have 2 A sessions (long ride + threshold run) and 3-4 B sessions per week.

In TriPaced: In TriPaced, key sessions are marked with a star (★) in the Plan view. The planner places them mid-week and at the end of the week to maximize recovery between them. If you need to skip a session, start with the B sessions : A quality takes precedence over total volume.

A recovery week involves a planned reduction in volume and/or intensity, without eliminating training entirely. Typical frequency: every 3-4 weeks of loading (3:1 or 4:1 model). During the recovery week, the body consolidates adaptations (supercompensation), repairs micro-lesions, and replenishes glycogen stores. Common mistake: not recovering enough out of fear of 'losing fitness.' Reality: adaptations are built during recovery, not during effort. The pre-race taper is distinct from a recovery week : it's shorter (3-5 days) and less dramatic.

In TriPaced: In TriPaced, recovery weeks are automatically built into the plan based on the chosen periodization model. They appear in the Plan view with the label 'Recovery week : reduced load.' Target volume is reduced to ~50-60% of the preceding week; intensity remains moderate.

The Critical Power model (Monod & Scherrer, 1965, adapted by Poole & Jones) defines two parameters: CP (critical power) and W' (anaerobic work capacity in joules). Any power above CP draws from W', which depletes in a few minutes. FTP (20-min test) slightly overestimates CP by about 5-10%. A more precise CP test chains two maximal efforts at different durations (e.g., 3 min + 15 min) then fits the model. In Ironman, riding is below CP : the risk of depleting W' on the bike is low with correct pacing, but a hard climb or sudden surge can draw from it and degrade the run.

In TriPaced: In TriPaced, FTP (CP proxy) calibrates bike power zones. The CP model is not yet exposed in the UI, but the planner accounts for the fact that in Ironman the core bike effort must stay below FTP threshold to preserve W', noted in the Race A sheet guidelines.

An Ironman result is not just the total time : splits reveal where time was gained or lost. Example: a total time of 11h might hide a 1h10 swim, T1 of 8 min, bike of 5h40, T2 of 5 min, run of 4h. Results platforms (Ironman Tracker, Athlinks) publish official per-segment splits and rank you within your age group. Analyzing splits across races guides training planning: if the run consistently degrades, work on brick specificity and bike nutrition.

In TriPaced: In TriPaced, your race splits are entered in the Race A/B sheet after the event. The projected vs. actual comparison across segments automatically identifies underperforming disciplines to guide the following season's planning.

In amateur (non-pro) triathlon, competitors are ranked in their age category based on their age during the race year: 18-24, 25-29, 30-34... through 75-79 and 80+. The age used is the one reached during the calendar year of the race, not the actual age on race day. Each category receives a proportional number of qualification slots for Ironman World Championship events (Kona and Nice since 2023). AG rankings are public on Ironman Tracker; they're often more motivating than the overall ranking. The M35-39 category is typically the largest and most competitive.

In TriPaced: In TriPaced, your age group is set during onboarding. It enables the display of your AG rank in race results and the calculation of a realistic time goal based on median and top-10 performances in your category across similar events.

Under WTC/Ironman rules: wetsuit permitted if water T° ≤ 24.5°C, banned if T° ≥ 25.5°C, optional in between (but the athlete waives ranking if pros don't wear one). Estimated gain: 1-3 min over 3.8 km. The zipper is at the back : practice opening and removing it in 30-40 seconds during T1 drills. Two types: sleeveless (faster to remove, less buoyant), full-sleeve (more buoyant, warmer). Never use petroleum-based products on a new wetsuit : they degrade the material; prefer triathlon-specific lubricants.

In TriPaced: In TriPaced, the Race A/B sheet shows the average water temperature from recent editions of your race (when available), to anticipate wetsuit use. The training plan may include a few pool sessions with the wetsuit to get used to the shoulder movement restriction before race day.

Carbo-loading means raising carbohydrate intake (pasta, rice, bread) to 60-70% of total calories for 2-3 days before race day, while cutting training volume. Goal: top off muscle and liver glycogen stores. A well-loaded muscle can supply energy for 90-120 minutes of hard effort before glycogen runs out.

In TriPaced: In TriPaced, the race week view highlights a 'glycogen loading window' at D-3/D-2. The AI coach adjusts session intensity to preserve stores without adding fatigue.

A proper warm-up gradually raises heart rate and muscle temperature, improves joint lubrication, and primes the nervous system. For a triathlete, it typically includes 10-15 min of easy activity (easy spin or light jog), a few drills, and 2-3 progressive accelerations before intense blocks.

In TriPaced: In TriPaced, every hard session (intervals, threshold) includes a prescribed warm-up at the top of the session card. Duration is adjusted to match the main zone of the day.

A cool-down means continuing light Z1 effort for 5-15 minutes after the main block. It helps clear lactate, gradually lowers heart rate, and reduces next-day soreness. In triathlon, the bike-to-run transition can serve this role if the pace is very easy.

In TriPaced: In TriPaced, session cards include a 5-15 min cool-down based on session intensity. Recovery sessions don't need one: they are already entirely in Z1.

T1 is the first of two transitions. It starts at the swim exit and ends when you cross the bike mount line. Classic mistakes: wasting time removing the wetsuit (practice solo beforehand), forgetting the helmet before shoes (possible penalty), or going out too hard from T1 and blowing up on the bike.

In TriPaced: In TriPaced, the race plan shows a target T1 time based on your past performance and reference race times for your event.

T2 is the second transition. It starts at the bike dismount line and ends when you cross the run start line. Key strategy: run the first 400-800 m only slightly faster than target pace to prevent 'run-off-bike' (jelly legs). Legs that run normally after 4-8 minutes of bike-to-run : that's planned, not a sign to quit.

In TriPaced: In TriPaced, the race plan includes a target T2 time and a run start tip: the first 2 km of the run are often 15-20 s/km slower than the final target pace : that's planned, not a sign to quit.

Swimming in the draft of a slightly faster swimmer can cut your energy use by 10-20%. The optimal position is behind their feet (0.5-1 m) or off to their side (hip level). In long-distance triathlon, swim drafting is ALLOWED, unlike bike drafting which is penalized. Learning to position in a draft is a trainable skill.

In TriPaced: In TriPaced, long-distance race swim tips include a wave-start placement strategy to exploit the draft of slightly faster swimmers.

A pacer can be an athlete running beside you to hold pace (common in trail and marathon), or a slightly faster group you latch onto during a race. In solo triathlon, the 'virtual pacer' is your pre-calculated target pace. GPS and automatic splits fill this role.

In TriPaced: In TriPaced, your target race pace is calculated from your vVO2max/threshold pace and your fatigue history on race day. It's your virtual pacer built into the race plan.

Heat acclimatisation (30 C, 70% humidity in full sun) requires roughly 10-14 days of training in those conditions for the body to increase plasma volume, improve sweating efficiency, and lower heart rate at a given effort. Arriving 2 weeks before race day in the race location is the ideal approach for an Ironman in a hot environment.

In TriPaced: In TriPaced, the Race A card shows average climate data for your race venue (air/water temperature, humidity) to help you plan your arrival date and final heat training sessions.

A chest strap monitors the heart's electrical activity (simplified ECG) and transmits via Bluetooth or ANT+ to your watch or bike computer. It is significantly more accurate than wrist optical sensors, especially during high-intensity efforts, climbing, or in cold conditions (low skin perfusion). Essential for reliable HR-zone training.

In TriPaced: In TriPaced, the heart rate zones used in your sessions are calculated from your FCmax and resting HR. For best accuracy, use a chest strap (not optical) during threshold or VO2max sessions used to calibrate these zones.

Aerobic capacity covers two dimensions: peak aerobic power (VO2max, a genetic ceiling that is trainable) and aerobic economy (how much oxygen you consume at a given pace). In long-distance racing, this aerobic base determines what fraction of VO2max you can sustain over 42 km. Z2 training during base and build phases is the most effective way to raise it.

In TriPaced: In TriPaced, the Z2 volume in your plan (long rides and runs, base endurance) is calibrated to build aerobic capacity first. It's the foundation on which high-intensity sessions (intervals, threshold) then stack.

A PR (Personal Record) or PB (Personal Best) is the fastest time you have ever run on a specific distance: PR marathon, PR ironman, PR 10k... It's the most personal benchmark for tracking progress. A PR on the same race 2 years later means you improved under comparable conditions. A flat PR cannot be directly compared to a mountainous one (in trail, CR : Course Record on a specific route : is the relevant metric instead).

In TriPaced: In TriPaced, your PRs on key distances (sprint, olympic, half, ironman, marathon, 10k...) are stored in your profile and used to calibrate your performance goals and target race paces.

A DNF (Did Not Finish) happens when you decide to stop mid-race: injury, illness, accumulated penalties, or judging that continuing would be unsafe. DNS (Did Not Start) applies when you are registered but don't toe the start line, often due to injury or illness. DQ (Disqualification) results from a rule violation: illegal drafting, outside assistance, unserved penalties. A DNF in long-distance racing is not shameful : it is sometimes the smartest call.

In TriPaced: In TriPaced, you can log races with a DNF, DNS, or DQ status. These events are excluded from your PR calculations but remain in your history to track root causes (injury, overtraining, poor nutrition prep).

The ramp test is an alternative to the 20-min FTP test. Power increases by 20 W (or pace by a few seconds/km) every 1-2 minutes. The test typically lasts 15-25 min. Estimated FTP equals roughly 75% of peak power at the last completed step. Advantage: psychologically easier than a sustained 20-min effort, so more reproducible. Limitation: the 75% estimator can be less accurate for atypical athlete profiles.

In TriPaced: In TriPaced, if you complete a ramp test and record it in Strava (progressive max effort), the automatic FTP detection analyses 5-20 min power curves to select the best available estimator.

Sodium is the most abundant electrolyte in sweat (500-1500 mg/L depending on the individual). Losing too much sodium without replacing it causes hyponatraemia: symptoms ranging from nausea and headaches to confusion in severe cases. The classic long-distance mistake is drinking only water: dilution lowers blood sodium. The baseline rule: 500-1000 mg of sodium per hour beyond 2 hours of effort in the heat, via isotonic drinks, salted gels, or electrolyte tablets.

In TriPaced: In TriPaced, the race nutrition plan includes hourly sodium recommendations adjusted for expected temperature and race duration. The race-week prep card reminds you of the electrolyte strategy to follow the day before and during the race.

Strength training for triathletes is not standard gym work : it targets functional muscle chains (core, glutes, hamstrings, shoulders). The most useful exercises for long-distance: squats and lunges (cycling and run power), planks and rotational core (swim posture), rows (water propulsion), unilateral exercises (hip stability in running). During base phase: 2 sessions/week of 30-45 min. In competition phase, reduce to 1 maintenance session.

In TriPaced: In TriPaced, strength sessions are embedded in the weekly plan with a 'strength' or 'stability' label. Load is auto-adjusted by phase (base/build/peak) to avoid accumulated fatigue before key sessions.

A race simulation is the most powerful tool to validate your race strategy 4-6 weeks before the event. For a half or full ironman, it can be partial (2/3 of distance) or full. The goal is not peak performance but a full dress rehearsal: nutrition every X minutes as planned, target paces per segment, heat management, gear testing (shoes, wetsuit, bike kit). GI issues, overheating, or blisters found in simulation can be fixed before race day.

In TriPaced: In TriPaced, 'race simulation' sessions appear in peak phase as key sessions. They use the same pace calculations as your official race plan. After the simulation, the planner analyses the Strava effort to confirm you held target pace and adjusts the race-day goal if needed.

Caffeine is monitored by WADA but not prohibited. The effective dose for endurance is 3-6 mg/kg body weight, taken 45-60 min before effort or split across the race. It works by blocking adenosine receptors (the central fatigue molecule) and freeing fatty acids. For a 70 kg athlete: 200-400 mg. Gels, energy drinks, and caffeine shots allow precise dosing. Caution: highly individual effect : avoid if you have cardiac sensitivity or sleep disorders.

In TriPaced: In TriPaced, the race nutrition plan includes caffeine timing recommendations (pre-race dose + optional top-up at km 30-35 of the marathon or run segment of a half). Individual tolerance is factored in: if you don't regularly consume caffeine, the effective dose is often lower.

Sprint triathlon typically lasts 50-75 min for an intermediate athlete. Intensity is high across all 3 segments: swim near anaerobic pace, bike between Z4-Z5, run at 5-10 km race pace. It is technically demanding (fast transitions, wave start, bike pack corners) but accessible in terms of training volume (6-8 h/week is enough to finish). Clubs and Try-a-Tri events often use a super-sprint (375 m / 10 km / 2.5 km) for first-timers.

In TriPaced: In TriPaced, if your Race A is a sprint triathlon, the training plan adapts the preparation cycles (shorter base, more high-intensity sessions) and the race plan targets sprint-specific paces for each segment.

Olympic triathlon has been the international standard since 1989 (first Olympics appearance: Sydney 2000). Intensity is high throughout : near ventilatory threshold on the bike and in zone 4-5 on the 10 km run. It is the recommended stepping stone before long-distance: the technical foundations (open water swim, transitions, time-limited cycling) are the same, but the duration remains manageable. With 10-12 h/week over 16 weeks, an intermediate athlete can target a solid time.

In TriPaced: In TriPaced, the Olympic format triggers an adapted plan: 12-16 week cycles, high-intensity key sessions, shorter long sessions compared to long-distance. Speed and power zones are the same as for ironman, but emphasis shifts to high-intensity segments.

The 'wall' or 'bonk' describes the sudden onset of heavy legs and near-zero energy when the body has burned through all available glycogen. In long-distance triathlon it typically strikes on the run between km 25 and km 35. Its severity depends directly on fueling strategy and bike pacing : going too hard on the bike depletes stores before the run. Prevention: regular gel intake from the first minutes on the bike, before hunger strikes.

In TriPaced: In TriPaced, your plan calibrates bike intensity zones to preserve glycogen stores before the run. Race strategy alerts flag risk phases (km 60-100 on the bike) where backing off prevents the wall.

Hyponatremia occurs when you drink too much plain water without enough sodium intake, diluting the salt in your blood. Symptoms: nausea, headache, confusion : in severe cases, seizures. It is the opposite of dehydration: the fix is NOT to drink more but to add sodium (salted gels, electrolyte tablets, broth). In Ironman, risk rises in hot weather with many water stations.

In TriPaced: In TriPaced, race nutrition plans include regular sodium intake (400-800 mg/h depending on heat). Do not confuse thirst with hyponatremia risk: drinking to thirst remains safer than consuming at every aid station.

A 2% body weight loss from dehydration is enough to reduce aerobic performance by 10-20%. It causes increased fatigue, cramping and cardiac drift (higher HR at the same effort). In long-distance racing, the goal is not to replace 100% of fluid losses : aim for 70-80% to avoid the inverse risk (hyponatremia). Urine color remains the best indicator: pale yellow = well hydrated.

In TriPaced: In TriPaced, fueling plans suggest 500-750 ml/h in temperate conditions, adjusted for heat and individual sweat rate. Weighing before and after a long session gives your net fluid loss : the basis for your personalized hydration plan.

The 70.3 takes its name from the total distance in miles (about 113 km). Typical finish times range from 3:45 for elites to 7-8 h for back-of-packers. Unlike Ironman, riding close to threshold is possible on the bike, and the half-marathon is run near the limit. Efficient transitions and a smart swim start are key to conserving energy from the gun.

In TriPaced: In TriPaced, a 70.3 goal activates a middle-distance periodization: high-intensity bike blocks, regular brick sessions, and speed-focused swim volume. Your target race auto-detects the distance to calibrate weekly volume targets.

Ironman (also called long-distance or 226 km) is the flagship triathlon event. Finish times range from 8 h for elites to 16:45 (cutoff limit) for the back of the field. The key: managing bike effort (65-75% FTP) to arrive at the run with reserves. Nutrition is critical : ~60-90 g of carbs per hour from the bike onward : or the wall looms at run km 30.

In TriPaced: In TriPaced, an Ironman goal triggers larger weekly volumes, specific long sessions (bike 4-6 h, run off-bike 30-45 min) and a structured 2-3 week taper. The app calculates your target bike pace from your FTP to protect you from the wall.

The micro-cycle is the fundamental building block of structured training. In triathlon it typically covers 5-7 sessions spread across three disciplines. Its internal structure (recovery, intensity, volume sessions) depends on where you are in the meso-cycle (base, build, peak, taper). Three to four micro-cycles form a meso-cycle, typically with a deload week every 3-4 weeks to absorb adaptations.

In TriPaced: In TriPaced, every week of your plan is a micro-cycle optimized for your current load (ATL/CTL), your availability inputs, and your proximity to race A. The app automatically reshuffles session order if you postpone a session.

The meso-cycle sits between the week (micro-cycle) and the full season (macro-cycle). Each meso-cycle targets a specific adaptation: building aerobic base, developing threshold, VO2max work, or pre-competition taper. Classic long-distance triathlon progression: Base → Build → Peak → Taper, each phase forming a 3-6 week meso-cycle.

In TriPaced: In TriPaced, your plan is automatically structured into meso-cycles based on your race A date and current fitness. Volume/intensity ratios and deload weeks are scheduled to follow the Base → Build → Peak → Taper progression.

Specificity states that to improve at an event, you must train in conditions close to that event : pace, duration, terrain, intensity. For an Ironman, this means long bike rides at race pace, regular run off-bike sessions, and open-water swim sessions when possible. The more your training resembles your target race, the more adaptations transfer on race day.

In TriPaced: In TriPaced, key sessions in the Peak phase are automatically calibrated to your target race A pace (Ironman or 70.3). Brick blocks, run threshold intervals, and swim efforts in competition zone are direct applications of this principle.

Functional overreaching is intentional overload followed by a taper, triggering supercompensation and gains. Non-functional overreaching is more severe, lasting over 2 weeks without improvement: it is the precursor to overtraining syndrome. Warning signs: persistent performance decline, fatigue that does not lift after 48 h of rest, falling HRV. Unlike overtraining (months of recovery), non-functional overreaching typically resolves in 2-4 weeks of relative rest.

In TriPaced: In TriPaced, CTL/ATL/TSB tracking detects non-functional overreaching signals: a persistently very negative TSB (−30 and below over multiple weeks) paired with declining performance is the cue to reduce load immediately.

Fueling refers to the complete nutrition and hydration strategy during racing. In Ironman, the carbohydrate target is 60-90 g per hour (trainable to 100-120 g/h with practice). The main window is the bike : where you can eat without GI distress. On the run, intake drops but remains critical. Good fueling prevents the wall, compensates sodium losses and sustains mental focus to the finish.

In TriPaced: In TriPaced, the fueling strategy is calibrated to your estimated race duration (calculated from your current fitness). Long session and race simulation cards include fueling cues to train your gut before competition.

In the Critical Power model, W' (pronounced 'W prime') represents the total anaerobic energy available. Any power above CP depletes W' at a rate proportional to the excess over CP. Once W' is empty, sustaining power above CP is impossible. W' recharges below CP, but slowly. In Ironman racing, deliberate W' depletion is rare, but an aggressive climb or too-fast start can draw from it. Knowing W' helps manage surges and hard passages.

In TriPaced: In TriPaced, FTP is used as a CP proxy to calibrate power zones. The W' model is not yet directly exposed in the interface, but the Ironman plan is designed to keep power below CP and preserve W' for the run.

Residual fatigue is the unrecovered fatigue that accumulates block after block. It differs from acute fatigue (immediate post-session): it persists for days even with good sleep. Indicators: low morning HRV, elevated resting HR, heavy legs at session start. It is normal during build phases but must be cleared during recovery weeks. CTL does not directly capture it: a very negative TSB (below -25) and a drop in retested FTP reveal it. A triathlete in week 3 of a 4-week block typically carries 15-30 points of residual fatigue.

In TriPaced: In TriPaced, the programmed recovery week in each block specifically targets clearing residual fatigue. The calculated TSB (CTL minus ATL) returns to positive during this week. Arriving at a race with a very negative TSB often signals uncleared residual fatigue.

The MAF method (Maximum Aerobic Function) by Dr Phil Maffetone uses the formula 180 minus age (in bpm), adjusted a few points based on health status and training history. The goal is to train exclusively below this HR for several months to build a solid aerobic base. The theory: above this HR, the body recruits fast-twitch fibres and produces lactate, slowing aerobic adaptation. In practice, for a healthy 35-year-old athlete, MAF HR is 145 bpm. The method is often combined with a MAF test (3-5 km at constant MAF HR) to measure base aerobic pace and track progress.

In TriPaced: In TriPaced, MAF is not the primary target zone (Coggan/Friel zones are used). But the aerobic threshold HR calibrated during onboarding often sits 5-10 bpm above MAF. During long base phases, some Z2 sessions can be done at MAF HR to maximise fat adaptation.

In Ironman competition, the target is 60-90 g of carbohydrates per hour, sometimes more. The problem: most athletes cannot tolerate these amounts without prior training. Gut training means progressively consuming more carbohydrates during long training sessions, starting at 30-40 g/h and increasing by 10-15 g/h per week. The gut adapts by upregulating SGLT1 and GLUT5 transporters to absorb more glucose and fructose simultaneously. Typical progression takes 4-8 weeks. Practically: train with the exact race-day products (same brand, same flavour) to test gastric tolerance at race-pace intensity.

In TriPaced: In TriPaced, long sessions and bricks are the prime opportunities for gut training. Session cards include a target carbohydrate quantity reminder. Starting gut training 8-12 weeks before the main race is recommended.

Bike fit is the adaptation of bicycle geometry (saddle, bars, stem, aerobars) to the athlete's body and goals. For long-distance triathlon, a good fit must solve a dual objective: an aero position to reduce CdA (aerodynamic drag) while preserving muscular capacity for the run. A poor fit causes pain (knees, lower back, neck), reduces power transfer and fatigues muscle groups that should not be engaged. Key elements: saddle height (knee angle 25-35 degrees), saddle setback (KOPS), drop handlebar vs aero pad, torso angle and reach.

In TriPaced: In TriPaced, bike fit is not directly integrated into planning, but it is mentioned in pre-season recommendations. A professional fit is advised before increasing bike volume beyond 5 hours per week. If you experience persistent pain on the bike, pause the session: that is a fit signal, not a volume signal.

Fat adaptation refers to physiological adaptations that increase the body's capacity to oxidise fatty acids at moderate intensity (Z2). It develops through high Z2 volume, occasional fasted training, and low-carbohydrate nutrition on easy days. In an Ironman, a well-adapted athlete can burn over 1 g of fat per minute, sparing glycogen for high-intensity moments, especially the final run.

In TriPaced: In TriPaced, long Z2 sessions (70-80 % of total volume) directly build fat adaptation. The planner prioritises this aerobic base in the Base and Build phases before introducing threshold blocks.

The double-threshold protocol, popularised by Norwegian coach Marius Bakken and later used by Jakob Ingebrigtsen, consists of two sessions around the lactate threshold (LT2) on the same day, separated by a few hours of rest. The aim: activate lactate transporters (MCT1/4) twice to force a superior lactate clearance adaptation compared to a single equivalent session. In long-distance triathlon, this protocol is mainly applied in running during Build and Peak phases.

In TriPaced: In TriPaced, double-threshold appears in advanced Build and Peak plans when weekly volume exceeds 10-12 h. It is shown in the session card as 'complementary LT2 session' and is only prescribed when morning recovery is satisfactory (HRV and resting HR within limits).

Plyometrics groups exercises that exploit the stretch-shortening cycle: hops, jumps, bounding, dynamic high-knees. By rapidly loading the Achilles tendon, patellar tendon and plantar fascia, they improve elasticity and energy return. For triathletes, the main effect is better running economy (less energy expenditure at the same pace). Two to three sessions of 10-15 min per week, added at the end of a Z2 run, are enough to see gains in 6 to 8 weeks.

In TriPaced: In TriPaced, plyometric sessions appear as short strength sessions in the Base and Build blocks. They score low TSS (8-12 TSS) with little impact on total volume. Recommended progression: vertical hops, then bounding, then lateral jumps, over 4 weeks.

Gastric emptying regulates the rate at which food and drink pass from the stomach to the intestine where they will be absorbed. At rest, this rate is around 500-800 ml/hour for isotonic fluid. In racing, it drops with intensity (blood flow diverted to muscles) and becomes one of the main limitations to energy intake. Blocked emptying (exercise-induced gastroparesis) shows up as nausea, heaviness, bloating, sometimes vomiting. Factors that speed it up: liquid rather than solid, carb concentration under 8%, drink temperature close to body, moderate intensity. Factors that block it: concentration over 8%, very cold drinks, intensity above threshold, dehydration.

In TriPaced: TriPaced recommends testing your nutrition strategy in long sessions with target concentration (often 6-7% carbs) and planned intensity. If emptying blocks in training, it will also block in the race: better to discover it in a long session than 90 min into the Ironman bike. The tip 'Nutrition failure in race: plan B at aid station' provides the gastric reset protocol.

Exercise-induced hypoglycemia occurs when hepatic glucose production no longer matches muscle demand, typically beyond 90 min of continuous effort if external carb intake is insufficient. Early signs: power drop without external cause, intense hunger, cold sweating, light-headedness. Untreated, it can lead to complete blackout (bonk / marathoner's wall) with inability to continue. On a half-Ironman, it is rare before 3h of effort if the carb strategy is correct (>60 g/h). On a full Ironman, it is the first nutrition risk between 5h and 9h of racing. Immediate treatment: 20-30 g fast carbs + intensity cut 15% for 15-20 min, gradual return to target pace.

In TriPaced: TriPaced calibrates its long sessions beyond 2h with a nutrition prescription proportional to intensity: at least 60 g carbs/hour beyond 3h, 80 g/h beyond 4h. External glucose becomes the primary fuel after 90 min of racing. The tip 'Nutrition failure in race' details early signals and the aid-station plan B.

Exertional hyperthermia occurs when metabolic heat production (80% of energy used by muscles degrades to heat) exceeds dissipation capacity via sweat and convection. It develops progressively, with core temperature rising 0.1-0.2°C per 10 min of running in hot climate. Severity signs: headache, confusion, hot red skin without sweating, tremors, nausea. Beyond 40°C core, risk of exertional heat stroke, medical emergency. Risk factors: ambient temperature >25°C, humidity >70%, no prior acclimatization, dehydration, hyperventilation. Prevention: heat acclimatization 10-14 days before hot race, pre-cooling with ice slush or ice pack at race start, hydration with electrolytes, pace reduced by 5-15 sec/km depending on condition severity.

In TriPaced: TriPaced does not yet auto-prescribe heat acclimatization. Practically: if your race is expected above 25°C and you do not train in those conditions, plan 10-14 days of progressive exposure (20 min sauna, late afternoon covered sessions, unventilated home trainer) 2-3 weeks before the race. The glossary term 'chaleur' provides race strategies in hot climate.

In open water or Ironman, there is no black line on the pool floor: navigation relies on head lifts ('sighting') every 6 to 10 strokes depending on visibility and current. The classic technique is the 'croc': before breathing, lift your eyes above the surface without raising your head fully (chin stays low), spot the landmark for 1 second, then rotate to breathe normally. Benefit: less body position disruption than a full head lift. Common errors: sighting too often (fatigues shoulders), imagining a straight line (current and waves deviate trajectory), aiming at other swimmers (they zigzag too). A poorly navigated Ironman swim can add 100 to 200 m of extra distance.

In TriPaced: TriPaced does not yet measure actual swim distance (Garmin SWIM 2 GPS required). In practice: during open water sessions, aim for a 'croc' every 8 strokes and record your GPS track to measure deviation from the straight path. A skilled swimmer rarely deviates more than 3 to 5% from theoretical distance.

Lactate is not waste: it is fuel. When you exceed your lactate threshold (LT2), lactate production surpasses consumption and blood concentration rises (inverted J-curve). Lactate clearance is the ability of your slow-twitch muscles (type I fibers) and heart to re-consume this lactate as energy substrate. Training that improves it: threshold intervals (Z3 sustained, 20-40 min), over-under intervals (Z4/Z2 alternation in 4-6 min blocks), and plain endurance volume increasing mitochondrial density. In triathlon, good lactate clearance lets you push harder on climb phase 2 without leg burn or irreversible acidification.

In TriPaced: The TriPaced engine derives your lactate threshold (LT2) from the inflection point of your HR/pace curve on 20-60 min Strava efforts. A high CTL combined with a high FTP/vVO2max generally indicates good lactate clearance. If your Z4 intervals degrade quickly by repetitions 3 and 4, that signals insufficient clearance training.

Polarized training, formalized by Stephen Seiler from analysis of elite endurance athletes' training logs, observes that the world's best athletes (rowers, cross-country skiers, triathletes) distribute their volume approximately 80% at low intensity (Z1-Z2, below first threshold) and 20% at high intensity (Z4-Z5, above second threshold), with very little time in the moderate zone (Z3). The physiological hypothesis: the moderate zone (roughly at lactate threshold LT2) accumulates too much metabolic fatigue relative to adaptation gain, whereas very slow sessions develop mitochondrial density without stress, and very hard sessions stimulate VO2max and lactate tolerance. In practice for an amateur triathlete: this means making long sessions truly slow (HR <70% HRmax), reserving 20% high intensity for quality sessions done fully recovered, and resisting the urge to 'semi-push' constantly.

In TriPaced: TriPaced plans implicitly incorporate polarization: base weeks concentrate long outings at low HR and reserve quality intervals to 1-2 sessions per week per discipline. If most of your Strava sessions cluster in Z3, this typically signals pushing 'easy' sessions too hard and 'hard' sessions not hard enough. TriPaced detects this via HR zone distribution from Strava imports.

SWOLF (SWimming gOLF, by analogy with golf where you aim for the lowest score) is a composite indicator combining stroke efficiency (fewer strokes per length = better propulsion) and speed (fewer seconds). It is measured per 25 m length (pool) or 50 m. Example: 25 strokes + 42 seconds = SWOLF 67. Reference range for an intermediate swimmer in a 25 m pool: 45-60 excellent, 60-70 good, 70-80 needs improvement, >80 review technique. Interpretation: a declining SWOLF with training indicates more glide, less parasitic undulation, and better arm-hip coordination. SWOLF is not comparable between 25 m and 50 m pools (50 m values are mechanically higher). Garmin and Apple Watch automatically calculate it in pool swimming mode.

In TriPaced: TriPaced does not yet import SWOLF directly from Strava or Garmin Connect (swim activities use separate fields). In the meantime, you can log your target SWOLF in the session notes field. A concrete Ironman goal: going from SWOLF 75 to SWOLF 65 over 12 weeks through 2 technical sessions per week (pull buoy drills, catch-up, fist drill).

Stroke rate (SR) counts how many full arm cycles you complete per minute. A beginner swims at 50-60 SPM, a pool swimmer at 60-75, an open-water competitor at 75-90. Rate alone means little: its relationship to distance per stroke (DPS) defines efficiency. A good Ironman swimmer targets 65-75 SR with maximum DPS (fewer strokes = optimal glide). Key drill: tempo-trainer sets to explore different rates and find your personal optimum.

In TriPaced: TriPaced does not yet read stroke rate directly from Strava (Garmin-specific field). You can log your target SR in session notes. Recommended drill: 10 x 50 m with a tempo trainer at 65 BPM, increasing by 2 BPM per set to find your optimum.

Cardiac drift is the slow HR rise observed on 2+ hour sessions at constant pace. It results from reduced plasma volume (sweating), blood redistribution to the skin (thermoregulation), and increasing glycogenolysis. A drift below 5% is acceptable (e.g., HR goes from 140 to 147 over 3 h). Above 8-10%, session quality drops and overheating risk rises. Drift is a sensitive indicator of hydration and daily form.

In TriPaced: TriPaced detects cardiac drift on long Strava activities (> 90 min) via the session analysis module. When drift exceeds 8%, the session is flagged as 'high drift' and a hydration reminder appears in the recap.

The metabolic window covers the first 30-45 minutes after exercise, when muscles are particularly insulin-sensitive. Glycogen resynthesis is 2-3x faster in this window than beyond 2 h. The reference recommendation is 1.2 g/kg carbohydrates + 0.3-0.4 g/kg protein within 30 min. For a 70 kg athlete: 84 g carbs + 21-28 g protein, e.g., a large bowl of pasta with protein powder, or 2-3 plain yogurts with a banana.

In TriPaced: TriPaced highlights the recovery window in the session recap when effort exceeds 90 min, 800 kJ (cycling), or 15 km (running). A 'Post-effort nutrition' panel shows target values calculated from your reference weight.

Carbon-plated shoes combine extremely soft foam (PEBA or high-restitution TPU) with a rigid carbon blade. The dual mechanism: foam absorbs and returns ~80% of kinetic energy (vs 65% for standard foam), while the plate reduces forefoot flexion, reducing calf and Achilles tendon fatigue. Running economy gains are estimated at 2-4%. In triathlon, they are allowed in the run segment of Ironman and WTC events.

In TriPaced: TriPaced does not yet distinguish shoe type in plans (paces are calibrated to your profile). If you switch to carbon-plated shoes, expect a 2-3% pace gain at equal effort and recalibrate your running threshold (running FTHR) after 2-3 test sessions.

Pre-race nutrition has two goals: saturating muscle and liver glycogen stores and ensuring digestive comfort. Day before: moderate glycemic index foods (pasta, rice, bread), high fluid intake (2-3 L with electrolytes). Race morning (2-3 h before start): light meal low in fibre and fat, 60-90 g carbs (oatmeal and honey or white bread and jam). Avoid unfamiliar foods, spices, legumes. Last gel 15-20 min before start if needed.

In TriPaced: TriPaced shows a 'Race day -1 and race morning' protocol in the Today view when a race is scheduled that week. Quantities are calculated from your reference weight and race type (sprint, 70.3, Ironman).

During exercise, muscles produce 3-5x more heat than at rest. The body dissipates it mainly by evaporation (sweating, 80% of dissipation). When core temperature exceeds 38.5 degrees C, performance declines. Above 40 degrees C, exertional heat stroke becomes a critical risk. Aggravating factors: high ambient temperature, humidity above 60%, high intensity, dehydration. Precooling strategies (ice vest, cold drinks) and race cooling (water on head, sponges) delay reaching critical thresholds.

In TriPaced: TriPaced includes a heat index in race preparation (forecast temperature and humidity) and adjusts pace targets for hot days (+15-20 s/km above 28 degrees C). The session recap flags workouts with heat-related cardiac drift.

Cold water immersion (below 18 degrees C) triggers the 'cold shock response': sudden HR spike, reflex hyperventilation and peripheral vasoconstriction in the first 30 seconds. This response causes dangerous involuntary inhalation. Adaptation occurs over 3-6 progressive sessions. Below 15 degrees C, technique degrades (numb fingers, loss of proprioception). In Ironman competition, wetsuits are mandatory below 20 degrees C (WTC regulations). Acclimatisation also reduces cold-induced headaches in very cold water.

In TriPaced: TriPaced displays the expected water temperature in race details when available from weather forecasts. If below 20 degrees C, a 'wetsuit required' badge appears in the Plan view for your race week.

Created by Dr Kenneth Cooper in 1968, this test involves running 12 minutes at the highest sustainable pace on a flat track. The formula estimates VO2max (mL/kg/min) = (distance in metres - 504.9) / 44.73. Example: 3000 m in 12 min = estimated VO2max of 55.8 mL/kg/min. Highly accessible, less precise than a lab test but allows regular monitoring. Limitations: it also measures the ability to sustain intense effort, not metabolic VO2max alone. Perform it in stable fitness conditions, without a hard session the day before.

In TriPaced: TriPaced does not yet handle the Cooper test natively, but you can enter your estimated VO2max in Settings > Physiological profile. This value calibrates your running zones (Z1 to Z5) and adjusts session pace prescriptions.

Wetsuit status is checked by officials the morning of the race, 30-60 minutes before start, after measuring water temperature. IRONMAN and 70.3 rules for Age Groupers: wetsuit mandatory below 15.9 Celsius, allowed between 15.9 and 24.5 Celsius, forbidden above 24.5 Celsius. Pro rules are stricter (wetsuit only up to 21.9 Celsius). Maximum thickness 5 mm on torso. Benefit: the wetsuit improves buoyancy by 5-10 seconds per 100 metres for an average swimmer, and delays hypothermia. Anticipate: if the race is marginal (~24 Celsius), prepare both options in T1 with your wetsuit laid out.

In TriPaced: TriPaced does not yet handle race-day weather, but the race card in Settings > Race A lets you set expected water temperature. The taper will prescribe 1-2 wetsuit swims in week -2 to test fit and shoulder-stroke feel.

Drafting reduces the following rider's energy cost by 15-30%. In long-course non-draft-legal triathlon (Ironman and 70.3 Age Group), it is forbidden. IRONMAN rules: 12 metres front wheel to front wheel on standard bikes, 25 seconds to complete a pass (following rider's front wheel behind your rear wheel, then in front of your front wheel). Motorbike marshalls patrol the course. Penalty: 5-minute time-out (tent). 3 penalties = disqualification. Tip: keep a 15-metre buffer for safety. In technical zones (tight corners, aid stations), officials tolerate mild bunching without penalty.

In TriPaced: TriPaced does not evaluate drafting (no GPS-based tracking), but the race card in Settings > Race A recaps event-specific rules. On long training rides, if you ride in a group, the target IF stays the same: riding without drafting is what actually trains you for race day.

Sub-10 is the benchmark that separates strong Age Groupers from amateur elites on Ironman. Standard splits for sub-10: swim ~1h05, T1 ~4 min, bike ~5h05 (36 km/h average, IF 0.72), T2 ~3 min, marathon ~3h35 (5:04/km). Requires sustained CTL > 100 over 12 weeks and favorable weather. On hilly course (Roth+, Cozumel-, Nice+), add 10-20 min. Sub-10 finish distribution varies strongly by sex (< 1% of women finishers) and age (concentrated 30-45 y.o.).

In TriPaced: TriPaced does not have an explicit sub-10 mode, but if your race A is an Ironman and your predicted finish in Perf is under 10:30, the planner adjusts key sessions (long-run negative split, 4h30 bike block at IF 0.72, post-transition brick) to align physiology with the objective.

The IRONMAN World Championship (Kona for men, Nice for women in 2026-2027) qualifies participants via allocated slots per qualifying race. Each Age Group category (M30-34, F45-49, etc.) receives 1 to 3 slots depending on field size. Slots are attributed via roll-down: first in category accepts or declines, then 2nd, etc. Typical qualifying times (M30-34 European race): sub-9h30 for certainty, sub-10h to hope for roll-down. Alternative: Ironman Legacy Program (12+ IRONMAN finishes, 1 slot per year guaranteed).

In TriPaced: TriPaced does not model Kona slots (proprietary IRONMAN data), but you can set your target finish time in Settings > Race A and the plan converges towards this goal. For a Kona qualifier, target sub-10h finish + top-3 category on moderate European race.