Effects of different walking speed on ankle muscle onset timing in middle-aged healthy adults

Introduction: Plantarflexor muscles produce propulsive force in the second half of stance phase; deficient motor output from these muscles would lead to inadequate propulsion at push off and decreasing walking speed. This study has examined the effects of walking on a treadmill at varying gradients and speeds on ankle muscle timing in healthy middle-aged adults. Materials and Methods: Fifteen healthy middle-aged adults (10M/5F; average age 56.53±7.20 years; body mass index 28.52±3.70 kg/m2) participated in the study. Participants walked on a standard treadmill at three different walking speeds (self-selected, self-selected+20%, self-selected+40%) and positive inclines (0°, 3°, and 6°). The onset muscle timing of MedialGastrocnemius (MG), and Tibialis Anterior (TA) muscles recorded at push off phase of the gait. Results: A linear mixed model (LMM) regression analysis was used to analysis. The onset of MG and TA muscles activity delayed at faster speeds on the nonodominant side (p<0.05). However, there is no changes with increasing treadmill speed and slope on muscles onset timing on the dominant side (p>0.05). Conclusion: Data showed that there is a bias towards using dominant side to overcome challenging walking conditions in middle-aged adults.