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

Military boots mileage is a main factor that can affect the risk of running injuries. The present study aims to evaluate the effect of three types of military boots mileage on knee muscular co-contraction during running.

Fifteen healthy males received three pairs of new military boots. Participants wore these boots for more than 6 months. Electromyography activity of lower limb muscles during running at constant speed was recorded during pre- and post-intervention. Then, knee muscular co-contraction was calculated.

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. 

It can be concluded that knee joint instability while using polyurethane thermoplastic is more than polyurethane boots. Also, our results demonstrated that maintaining knee stability in the anterior-posterior direction while using polyurethane thermoplastic is better than in polyurethane boots.