Context: Asymmetrical loading between lower limbs can theoretically be explained as an inequality of strength, neuromuscular control, or subconscious reliance on one leg more than the other. Asymmetries are often identified utilizing costly equipment such as force plates and 3D motion analysis cameras. It is important to establish less costly ways of identifying movement and loading asymmetries for clinicians to utilize. One qualitative assessment that may identify asymmetries is a ‘lateral hip shift’ during an overhead squat. Objective: To identify differences in lower extremity range of motion (ROM) and plantar foot pressures in individuals with and without a lateral hip shift during an overhead squat. Design: Cross-Sectional Observation. Setting: Lab. Participants: Twenty-nine (14 males and 15 females) physically active individuals participated in this study. Seventeen individuals with a lateral hip shift during an overhead squat (LAT; Age = 21.2 ± 2.1 years, Height = 175.1 ± 9.1 cm, Mass = 77.6 ± 14.2 kg) and twelve without (CON; Age = 20.8 ± 2.1 years, Height = 177.4 ± 6.8cm, Mass = 77.8 ± 11.1kg) were identified throughscreening. Interventions: Participants were screened for a lateral hip shift while performing five overhead squats to determine group allocation (LAT, CON). All ROM measures were performed in a randomized order followed by additional trials of the overhead squat while standing on the pressure sensor mat. Main Outcome Measures: Active, passive, and weight-bearing ROM for ankle dorsiflexion (DF) and passive hip abduction, internal, and external rotation were measured. Plantar pressure variables were captured via a pressure sensor mat during the overhead squat, including side-to-side weight bearing %, anterior-posterior excursion (cm), left-right excursion (cm), and center of force (COF) distance (cm). Results: A significant group-by-limb interaction for active DF ROM, such that the LAT group had less active DF ROM with the knee flexed on the limb they shifted away from in comparison to the assigned CON limb (mean difference = 6.87º ± 0.2). The LAT group also had less active DF ROM with the knee extended (3.07° ± 1.25) compared to the CON group (8.30° ± 1.49). No differences were observed on other ROM variables. The LAT group demonstrated greater movement in their center of force on the plantar pressure mat for total distance (mean difference = 24.27 cm ± 0.4) and LR excursion (mean difference = 2.96 cm ± 3.2). Conclusion: Participants with a lateral shift during an overhead squat generally had decreased active ankle DF ROM and greater movement of their center of force. Clinically, addressing active DF ROM may promote more symmetrical loading during an overhead squat.
展开▼
