Fig. 9. The effect of limb length on vertical force production during walking and running. The magnitude of vertical ground force at a given speed, estimated as (contact time)^–1 / speed, decreases with hind-limb length. Group means are calculated from individual trials (walking and running trials combined). P-values are given for each comparison, calculated via Student's one-tailed t-test assuming unequal variance. Error bars indicate the standard error of the mean. Ranges for each hind limb-length category are: short 79–80 cm (N=2 subjects); medium 89–95 cm (N=4); long 103–112 cm (N=3).