Fig. 3.

Quadriceps muscle EMG activity during bodyweight, elastic and machine resistance exercise.

EMG activity of the quadriceps during, bodyweight (BW-RET), elastic band (EB-RET) and machine (MN-RET) resistance exercise training modalities in young (white bars) and old (grey bars) adults, with values presented as means ± standard deviation. * Indicates significant (P < 0.001) differences in muscle activity between groups; ^† significantly lower than MN-RET (P < 0.001); ^‡ significantly lower than EB-RET (P < 0.001).