Hip kinematics and muscle activity during the 1-legged squat
A study was conducted on women, investigating hip and knee kinematics and hip muscle function between good and poor performers on the single leg squat and the relationships between these variables. Increased knee valgus during the single leg squat was found to be correlated with increased hip internal rotation and adduction and decreased gluteus maximus activation levels.
Over the last decade, several mal-adaptive movement patterns during weightbearing tasks have been identified in individuals suffering from lower extremity injuries; hip adduction and internal rotation and frontal plane knee abduction seem to be present in various pathologic conditions. Hip strength and neuromuscular control, especially of the hip abductors and external rotators, is crucial for allowing optimal lower extremity kinematics.
41 healthy and active women participated in this study. Their performance on a single leg squat task was classified as “good” or “poor” based on standardized visual observation. Subsequently, isometric strength of the hip abductors was determined, as well as EMG activation of the gluteal musculature and 3-D hip and knee kinematics during the single leg squat.
An increase in dynamic knee valgus was correlated to increased hip internal rotation and adduction and decreased gluteus maximus activation levels. Even when controlling for hip kinematics, gluteus maximus activity was associated with frontal plane knee abduction. This highlights the importance of adequate hip abductor muscle strength and neuromuscular control for maintaining optimal movement patterns, even at the knee joint.
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> From: Hollman et al., Clin Biomech 29 (2015) 468-474. All rights reserved to Elsevier Ltd. Click here for the Pubmed summary.