Force generation ability in 11 muscles at eight speeds (mean and 1 s.d., N=5). Force generation ability of gastrocnemius lateralis (Gas lat), gastrocnemius medialis (Gas med), soleus, tibialis anterior (Tib ant), gluteus maximus (Glut max), gluteus medius (Glut med), vastus lateralis (Vas lat), vastus medialis (Vas med), biceps femoris long head (BFLH), semitendinosus (Semiten) and rectus femoris (Rec fem) in walking (darker bars, 1.0–1.75 m s−1) and running (lighter bars, 2.0–5.0 m s−1); a repeated measures ANOVA indicated that speed had a significant effect (*P<0.05) in five muscles during walking and three muscles during running.