Fig. 4.

Recommendations on the choice of regression analysis. a Time to exhaustion (dependent variable: t) is measured for a fixed running speed (s). Distance (d) is by induction a dependent variable. b Time trial and running speed (dependent variables) are measured for a fixed distance (independent variable). c Distance and running speed (dependent variables) are measured for a fixed time trial (independent variable). For sake of clarity, the models represented in the figures are not representative of the outcome of the measurements. They are only given to demonstrate where a regression method can be applied. WLS weighted least squares, CS critical speed, d′ distance that can be run above CS, CP critical power, W′ anaerobic work capacity