Frontal plane alignment during a single leg squat
Suboptimal frontal plane kinematics during the single leg squat have consistently been demonstrated in patients with lower extremity injuries. The link between frontal plane alignment and hip and core strength was investigated among women; it was found that both hip as well as core strength were significantly correlated with performance on the single leg squat.
Earlier studies have pointed to abnormal frontal plane knee alignment as a possible cause and a risk factor for patellofemoral pain syndrome; other studies showed increased frontal plane hip adduction angles, indicative of more pronounced involvement of proximal segments in the kinetic chain.
In this study, 40 asymptomatic women underwent peak strength measurements for the hip abductors, external rotators and extensors and for the sidelying plank. Subsequently, they performed five single leg squats while being videotaped – the latter allowing determining of the displacement of the markers and calculation of the frontal plane projection angle.
Both hip as well as core strength were significantly correlated to frontal plane alignment during the single leg squat, especially hip abductor strength was an important predictor of the frontal plane kinematics. The correlation between strength variables and frontal plane projection angle stresses the importance of a thorough investigation of the entire kinetic chain in patients with lower extremity and low back injuries.
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> From: Stickler et al., Phys Ther Sport 16 (2015) 66-71. All rights reserved to Elsevier Ltd. Click here for the Pubmed summary.