Contribution of a Muscle Fatigue Protocol to a Dynamic Stability Screening Test for Exertional Medial Tibial Pain

Background: Enhancing the accuracy of a risk factor screening test is an important element of sports injury prevention. Purpose: To determine the effect of muscle fatigue on a screening tool for those at risk of exertional medial tibial pain (EMTP). Study Design: Cohort study (prognosis); Level of evidence, 2. Methods: Sixty-nine female students in a physical education program with a mean age of 19.24 +/- 0.86 years were tested at the beginning of their first academic year and followed for 1 to 2 years. Participants completed an online questionnaire every week and a retrospective control questionnaire every 3 months, which were used to assess injury follow-up. A diagnosis of EMTP was made by an experienced medical doctor. A Cox regression analysis was used to identify the potential risk factors by comparing prefatigue and postfatigue data between uninjured participants and those with EMTP. Both the leg that developed EMTP and the contralateral leg were compared with legs of a matched control group. Results: During injury follow-up, 21 female participants were diagnosed with EMTP. Results of the comparison between uninjured versus EMTP participants, respectively, are as follows: For the leg at risk in the nonfatigued state, only increased range of motion in the transverse plane (ROMT) of the hip during landing could be identified as a risk factor (8.44 degrees +/- 2.94 degrees vs 11.69 degrees +/- 3.41 degrees; P = .002). In the fatigued state, increased ROMT of the hip and pelvis during landing (hip: 8.04 degrees +/- 2.34 degrees vs 9.36 degrees +/- 3.22 degrees; P = .038; pelvis: 6.99 degrees +/- 2.20 degrees vs 8.58 degrees +/- 3.13 degrees; P = .040) and increased ROMT of the thorax during pushoff (8.83 degrees +/- 2.74 degrees vs 10.69 degrees +/- 3.20 degrees; P = .036) could be identified. For the leg not at risk for EMTP, increased ROMT of the knee during landing (10.96 degrees +/- 3.12 degrees vs 14.07 degrees +/- 4.88 degrees; P = .023) and decreased ROMT of the pelvis during pushoff (8.16 degrees +/- 3.48 degrees vs 6.47 degrees +/- 2.47 degrees; P = .034) were identified in the nonfatigued state but were not significant in the fatigued state. Conclusion: Adding a muscle fatigue protocol to the single-legged drop jump as a screening test for EMTP risk factors may enhance the possibility of identifying the leg at risk in a predisposed athlete and might determine the proximal risk factors for that leg at risk more thoroughly.