Fig. 6. Normalised RMS values of the EMG signal (A) for the quadriceps femoris muscles (vastus lateralis, vastus medialis and rectus femoris) and knee joint moment (B) during isometric maximal voluntary knee extension contraction at 11 different joint angle configurations for the examined groups (means ± 1 s.d.). RMS values from each subject were normalised to the highest RMS value measured over all joint angle configurations. Group 1, high running economy; Group 2, moderate running economy; Group 3, low running economy. ^*Statistically significant differences between group 1 and the other two groups (P<0.05).