Tibial Stress Fracture

An Investigation of Factors Affecting Dynamic Postural Stability in Collegiate Cross Country Runners

Injury could lead to impaired postural stability which is commonly assessed during return-to-sport rehabilitation. The Dynamic Postural Stability Index (DPSI) estimates variability in tri-axial ground reaction forces. DPSI is higher in injured runners and predicts performance in soccer players. DPSI has also been related to ankle range of motion (ROM) and strength in military personnel. PURPOSE: To explore relationship between previous injury, ankle ROM and strength with DPSI in collegiate runners. METHODS: Twenty-seven Division I collegiate cross country athletes (19.8±1.3 years) participated. Athletes jumped over a hurdle on to an AMTI force plate and landed on a single leg for DPSI estimation. Three trials were performed bilaterally. Ankle ROM was assessed via active dorsiflexion and gastrocnemius length measurement. Ankle and hip strength were measured using a handheld dynamometer. An independent samples t-test was used to compare DPSI between injured (IG – those injured in the past 3 years) and uninjured (UG) groups. Pearson’s correlation coefficients were determined between DPSI and other variables. RESULTS: No significant difference was found for DPSI on left (IG: 0.30±0.03 vs. UG: 0.32±0.04) and right (IG: 0.30± 0.03 vs. UG: 0.31±0.03) sides. There was a significant moderate negative correlation between dorsiflexion ROM and DPSI (right side r= -0.605, p= 0.001; left side r= -0.452, p= 0.001). There were no correlations between strength and DPSI except for right inversion strength and right DPSI (r= 0.446, p=0.020). CONCLUSION: DPSI seems to be influenced to a greater extent by ankle dorsiflexion than strength or previous injury in a collegiate runners.
Listed In: Biomechanics, Physical Therapy, Posturography, Sports Science