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Published on: August 30, 2016
Prediction of Dynamic Postural Stability During Single-Leg Jump Landings by Ankle and Knee Flexibility and Strength
Valerie J Williams1, Takashi Nagai, Timothy C Sell
1Warrior Human Performance Research Laboratory, University of Pittsburgh, Pittsburgh, PA.
Context:
Dynamic postural stability is important for injury prevention, but little is known about how lower-extremity musculoskeletal characteristics (range of motion [ROM] and strength) contribute to dynamic postural stability. Knowing which modifiable physical characteristics predict dynamic postural stability can help direct rehabilitation and injury-prevention programs.
Objective:
To determine if trunk, hip, knee, and ankle flexibility and strength variables are significant predictors of dynamic postural stability during single-leg jump landings.
Design:
Cross-sectional study.
Setting:
Laboratory.
Participants:
94 male soldiers (age 28.2 ± 6.2 y, height 176.5 ± 2.6 cm, weight 83.7 ± 26.0 kg).
Intervention:
None.
Main Outcome Measures:
Ankle-dorsiflexion and plantar-flexion ROM were assessed with a goniometer. Trunk, hip, knee, and ankle strength were assessed with an isokinetic dynamometer or handheld dynamometer. The Dynamic Postural Stability Index (DPSI) was used to quantify postural stability. Simple linear and backward stepwise-regression analyses were used to identify which physical characteristic variables were significant predictors of DPSI.
Results:
Simple linear-regression analysis revealed that individually, no variables were significant predictors of the DPSI. Stepwise backward-regression analysis revealed that ankle-dorsiflexion flexibility, ankle-inversion and -eversion strength, and knee-flexion and -extension strength were significant predictors of the DPSI (R2 = .19, P = .0016, adjusted R2 = .15).
Conclusion:
Ankle-dorsiflexion ROM, ankle-inversion and -eversion strength, and knee-flexion and -extension strength were identified as significant predictors of dynamic postural stability, explaining a small amount of the variance in the DPSI.
