Kinematic and kinetic effects of knee and ankle sagittal plane joint restrictions during squatting

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
R. Lee Howard (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site:
Randy Schmitz

Abstract: "The purpose of this study was to evaluate compensatory biomechanical patterns in the lower extremity created by restricted knee flexion and ankle dorsiflexion when performing squats. Forty two healthy subjects (21 men, 21 women; 22.5 (4.5) years, 73.8 (17.8) kg, 167.5 (12.5) cm) participated in the study. Data were collected using a force plate and a 3-d electromagnetic tracking device for bilateral lower extremity analyses. Three parallel squats were performed in non braced, right knee restricted and right ankle restricted conditions. Dependent measures were hip, knee and ankle total joint displacement and work done on the hip, knee and ankle during the eccentric portion of the squat. Three repeated measures ANOVAs compared lower extremity kinematics between conditions, while one repeated measure ANOVAs evaluated lower extremity kinetics. Mean hip, knee and ankle ROM was reported, as was sagittal plane work done on the hip, knee and ankle for each condition and limb. The primary findings of this study indicate hip and ankle flexion displacement significantly decreased in the contralateral (non-braced) limb during the ankle joint restricted condition. Ipsilateral (braced) limb hip, knee and ankle flexion significantly decreased during the knee restricted condition, while ipsilateral knee and ankle flexion decreased during the ankle restricted condition. Lower extremity sagittal plane energetic changes occurred in the ipsilateral knee and ankle when the knee joint was restricted and at the ipsilateral ankle in the ankle restricted condition. Relative and absolute shifts in work done on the hip, knee and ankle when compared to the non braced squat were observed. This study may best serve as a general sagittal plane model for clinicians and coaches to reference when using the parallel squat in patients/athletes with knee and ankle dysfunction. This has practical significance to clinicians as these substitutions in work could result in overuse (secondary) injury to the compensatory site or insufficient loading to the dysfunctional site, rendering it weak and susceptible to additional primary injury or limiting the athletes maximal performance. "--Abstract from author supplied metadata.

Additional Information

Language: English
Date: 2005
compensatory biomechanical patterns, knee flexion, ankle dorsiflexion, squats, Lower extremity sagittal plane, energetic changes
Ankle--Wounds and injuries--Prevention
Knee--Wounds and injuries--Prevention
Ankle--Mechanical properties
Knee--Mechanical properties
Exercise--Physiological aspects

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