Background: The high incidence of lower limb overuse and acute injuries that occur in military populations suggests that fatigue may contribute to altered neuromuscular control of the ankle and knee joints. Moreover, deficits in ankle and knee joint position senses (JPSs) were seen in subjects with history of lower limb musculoskeletal injuries. The aim of this study was to evaluate if military exercises could alter the ankle JPS and to examine the possible relation of JPS to further lower limb musculoskeletal injuries in military service.
Materials and methods: 50 male conscripts from a unique base with same military training were recruited. Subjects were asked to recognize pre-determined position of the dominant ankle (21 degree of plantar flexion) before and after military exercises by continuous passive motion device (CPM). The average of the absolute error (AE) of three trials was recorded as scores for both conditions and results were compared. The subjects were followed for 8 weeks for any musculoskeletal injuries and the relationship between the incidence of lower limbinjury and JPS were determined by paired t-test.
Results: There was significant decrease in subject's ability to recognize passive and active repositioning of their ankle joint after a session of military protocol (p<0.001). There was a strong correlation between lower JPS acuity and occurrence of injury (r= 0.86, p<0.001 ).
Conclusion: The acuity of the ankle JPS is reduced subsequent to military exercises. Decreasing JPS accuracy was associated with growing incidence of lower limb musculoskeletal injuries.