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Limb Symmetry During Double-Leg Squats and Single-Leg Squats on Land and in Water in Adults With Long-Standing Unilateral Anterior Knee Pain; A Cross Sectional Study


Limb Symmetry During Double-Leg Squats and Single-Leg Squats on Land and in Water in Adults With Long-Standing Unilateral Anterior Knee Pain; A Cross Sectional Study

Anna C Severin et al. BMC Sports Sci Med Rehabil.


Background: The presence of pain during movement typically results in changes in technique. However, the physical properties of water, such as flotation, means that water-based exercise may not only reduce compensatory movement patterns but also allow pain sufferers to complete exercises that they are unable to perform on land. The purpose of this study was to assess bilateral kinematics during double-leg squats and single-leg squats on land and in water in individuals with unilateral anterior knee pain. A secondary aim was to quantify bilateral asymmetry in both environments in affected and unaffected individuals using a symmetry index.

Methods: Twenty individuals with unilateral knee pain and twenty healthy, matched controls performed body weight double- and single-leg squats in both environments while inertial sensors (100 Hz) recorded trunk and lower body kinematics. Repeated-measures statistics tested for environmental effects on movement depths and peak angles within the anterior knee pain group. Differences in their inter-limb symmetry in each environments was compared to the control group using analysis of variance tests.

Results: Water immersion allowed for greater movement depths during both exercises (double-leg squat: +7 cm, p = 0.032, single-leg squat: +9 cm, p = 0.002) for the knee pain group. The double-leg squat was symmetrical on land but water immersion revealed asymmetries in the lower body frontal plane movements. The single-leg squat revealed decreased hip flexion and frontal plane shank motions on the affected limb in both environments. Water immersion also affected the degree of lower limb asymmetry in both groups, with differences also showing between groups.

Conclusions: Individuals with anterior knee pain achieved increased squat depth during both exercises whilst in water. Kinematic differences between the affected and unaffected limbs were often increased in water. Individuals with unilateral anterior knee pain appear to utilise different kinematics in the affected and unaffected limb in both environments.

Keywords: Aquatic exercise; Asymmetry; Inertial sensors; Kinematics.

Conflict of interest statement

This project was conducted in accordance to the approval by the Human Ethics Research Committee at the University of the Sunshine Coast, which approved the research protocol and data collection instruments (S/15/742). All participants signed a written informed consent prior to any data collection.A signed consent form was provided for the publication of Fig. 1.The authors declare no competing interests.Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.


Fig. 1
Fig. 1
Photograph showing the set-up during the water-based session

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