Author(s): YOKOTA, K., NITA, Y., OGA, R., URA, A., MIYAZAKI, T., TAMAKI, H., Institution: NATIONAL INSTITUTE OF FITNESS AND SPORTS, Country: JAPAN, Abstract-ID: 968

INTRODUCTION:
The relationship between surface electromyographic (sEMG) activity and ground reaction force (GRF) factors has been shown to have significant implications for factors such as sprint running velocity and acceleration, as indicated in a previous study1. However, that study focused mainly on hip flexor/extensor muscles, with the ankle plantar/dorsiflexion muscles largely unexplored. Additionally, according to a recent study, sprint acceleration performance is strongly correlated with mean net anteroposterior force (mAP) normalized by body mass2. We therefore investigated the relationships between sEMG activity in the ankle plantar/dorsiflexion muscles and mAP during sprint running for each step in Japanese college sprinters.
METHODS:
Twelve male college track and field athletes performed maximal sprint running over 50 m. During this test, we recorded the sEMG signals from their tibialis anterior (TA) and soleus (Sol) muscles and GRF data using a 50 m force plate system (it recorded 26 steps, including the block-clearing phase as one step). The sprint-running phases were divided into three phases (stance, early swing, and late swing) based on GRF data. The sEMG signals were processed for normalization (expressed as a percentage of the maximum voluntary contraction) and integration (using the “trapz” function in MATLAB 2023 for each phase).
RESULTS:
There was a significant correlation between sEMG activity in the TA and mAP during each phase. Specifically, they were negatively correlated in the stance and early swing phases in many steps, but positively correlated in the late swing phase. However, there was little correlation between sEMG activity in the Sol and mAP during each phase of most steps.
CONCLUSION:
Our data suggest that sEMG activity in the TA during the late swing phase contributes to obtaining a higher mAP in 50 m sprint running. We therefore propose that sEMG activity in the TA before ground contact may predict the sprint-running acceleration of sprinters.
REFERENCES:
1 Morin et al., (2015), Frontiers in Physiology, 6:404
2 Nagahara et al., (2018), Sports Biomechanics, 20(3), 363–369