Fig. 2. Actual (gray, thick line) and modelled (black, thin line) forward speed s (m s^–1) as a function of time t (s) at the onset of a typical 100 m run for subject 7. Actual speed was accurately described by: s(t)=10.0*(1–e^–t/1.42). The maximal speed (s_max) was 10.0 m s^–1.