Co-contraction activity of ankle muscles during walking: A gender comparison

The study aimed to assess possible differences between healthy, young males and females in co-contraction activity of tibialis anterior and gastrocnemius lateralis during gait at self-selected speed and cadence. The Statistical-Gait-Analysis methodology, allowing a statistical characterization of gait by averaging spatial-temporal and sEMG-based parameters over hundreds of strides per walking trial, was applied on thirty age-matched subjects: 15 males and 15 females. Co-contractions were assessed as the overlapping periods between muscular activities. Results showed the occurrence of four different co-contractions during gait cycle, for both groups. No significant differences in activation instants (ON-OFF) were detected between groups. Otherwise, all the co-contractions occurred in higher number of strides (%) in females, respect to males: in early stance (40.7 ± 18.7% vs. 18.9 ± 11.0%, p < 0.001), mid-stance (41.5 ± 15.2% vs. 26.0 ± 22.8%, p < 0.005), pre-swing (16.6 ± 7.3% vs. 7.1 ± 4.7%, p < 0.001), and swing (79.4 ± 13.7% vs. 55.6 ± 19.3%, p < 0.001). This overall higher occurrence of ankle-muscle co-contractions, associated to a more complex muscular recruitment, seems to reflect a female need for a higher level of ankle-joint stabilization. Thus, present findings indicated gender as a not negligible factor in the interpretation of muscular co-contraction variability during walking and suggested the suitability of gender-based approaches in clinical studies and in developing reference frameworks.