Biomechanical abnormalities of pronated feet accompanied by functional leg length disparity may increase the risk of skeletal muscle injury. Objective of the study is to prove that correction of pronated feet by the foot orthoses will reduce the creatine kinase-MM (CK-MM) concentrations as the muscle injury indicator. The design study was double blind randomized clinical trials with control. Research subjects were divided into two groups, group 1 used the foot orthoses while group 2 did not used the foot orthoses. The whole subject examined the concentrations of the CK-MM enzyme before, and 24–72 hours after the walking test. The walking test was conducted 15 minutes with maximum speed. The concentration of the CK-MM enzyme before walking test on treatment group was 70.07±15.33 International Unit (IU), similar with the control group was 69.85±17.03 IU ( P =0.971). The increased in CK-MM enzyme concentrations 45 hours after the walking test was lower in the treatment group (7.8±9 IU) than the control group (22.0±11.5 IU) ( P =0.001). The CK-MM enzyme concentrations continued to decline in the treatment group after the second walking test (77.21±17.47 IU), and after the third walking test (69.86±11.88 IU) ( P =0.018). The foot orthoses for correcting the pronated feet on the young women with biomechanical abnormalities is able to reduce the degree of the skeletal muscle injury after walking activity.