The Effect of Three Types of Military Boots’ Mileage on Knee Muscular Co-Contraction During Running

Purpose: Military boots’ mileage is a main factor that can be influence the risk of sustaining injuries during running. The aim of the present study was to evaluate the effect of three types of military boots’ mileage on knee muscular co-contraction during running. Methods: Fifteen healthy males received three new pairs of military boots. They were asked to wear these shoes for over 6 months. Electromyography activity of lower limb muscles was recorded during running at constant speed during pre- and post-intervention. Then, knee muscular co-contraction was calculated. Results: Results showed a significant increase during loading response (P=0.030, n2p=0.157) and push off (P=0.008, n2p=0.302) phases for general knee co-contraction at post-test compared to the pre-test. Also, directed mediolateral knee co-contraction showed a significant increment during mid-stance (P=0.028, n2p=0.040) and push off (P=0.039, n2p=0.115) phases at post-test compared to the pre-test. Conclusion: Overall, it could be concluded that knee joint instability while using Polyurethane thermoplastic is greater than that using Polyurethane boots. Also, our results demonstrated that maintaining knee stability in anterior-posterior direction while using Polyurethane thermoplastic is better than that using Polyurethane boots.