Fig. 2. (A) Normalized RMS values of the EMG signal for the triceps surae muscle (gastrocnemius medialis, gastrocnemius lateralis and soleus) and (B) ankle joint moment during isometric maximal voluntary ankle plantarflexion contraction at 11 different joint angle configurations for the examined groups. Values are means ± S.D. RMS values from each subject were normalised to the highest RMS value measured over all joint angle configurations. O, older adults; Y, young adults. Asterisks indicate statistically significant differences between older and young adults: *P<0.05, **P<0.01, ***P<0.001; significant age-by-running activity interaction (P<0.05); significant differences between runners and non-active individuals (P<0.05).