CSS : Critical Swim Speed
SwimYour threshold pace in swimming, computed from a 400 m + 200 m test.
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.
Source Wakayoshi et al., 1992 : Critical Swim Speed as a measure of aerobic capacity