Fig. 7. (A) Moment arm of the ground reaction force (R) and (B) gear ratio (R/r) acting about the ankle joint during ground contact for the examined groups. Values are means ± S.D. of both legs. O, older adults; Y, young adults. (Phase 1, 10–26%; Phase 2, 26–42%; Phase 3, 42–58%; Phase 4, 58–74; Phase 5, 74–90% of the period of ground contact). Asterisks indicate statistically significant differences between older and young adults: *P<0.05, **P<0.01; there was no age-by-running activity interaction for the analysed parameters (P>0.05).