Co-activation of Knee Muscles in Female vs. Male Adults

Abstract

During walking, knee joint mechanics is primarily regulated by thigh-muscle group, i.e. hamstrings and quadriceps femoris. Research purpose was to assess gender-related differences in concomitant recruitment of antagonist knee-joint muscles during ground walking. To this aim, Statistical gait analysis was performed on surface-electromyographic (sEMG) signals from vastus lateralis (VL) and medial hamstrings (MH) in 15 female (F-group) and 15 male (M-group) age-matched able-bodied young adults. sEMG signals from numerous strides (average value ± SD of 452 ± 102 strides for F-group and 440 ± 106 strides for M-group) were analyzed for each subject. Results showed that the same three VL/MH co-activations were found in the gait cycle, irrespective of gender: during early stance (ES), push-off (PO), and swing (SW) phase. No significant gender-related differences (p > 0.05) were observed in co-activity duration. Differently, an increase of occurrence frequency was observed in F-group for VL/MH co-activation during PO phase, with respect to M-group (21.9 ± 13.6% vs. 11.3 ± 8.6% of strides, p = 2.5 × 10−3). This increased occurrence of co-activations suggests a more complex muscular recruitment for knee-joint stabilization in females, in particular in PO phase when the control of balance is more awkward because of the final phase of single support. In conclusion, the present study indicates gender as a not negligible factor in evaluating knee-muscle co-activation during walking.