Stooping, crouching, and standing – characterizing balance control strategies across postures

Publication date: Available online 6 January 2017
Source:Journal of Biomechanics
Author(s): Tyler B. Weaver, Michal N. Glinka, Andrew C. Laing
BackgroundWhile stooping and crouching postures are critical for many activities of daily living, little is known about the balance control mechanisms employed during these postures. Accordingly, the purpose of this study was to characterize the mechanisms driving net center of pressure (COPNet) movement across three postures (standing, stooping, and crouching) and to investigate if control in each posture was influenced by time.MethodsTen young adults performed the three postures for 60seconds each. Kinetic signals were collected via a force platform under each foot. To quantify mechanisms of control, correlations (CorrelLR) were calculated between the left and right COP trajectories in the anterior-posterior (AP) and medio-lateral (ML) directions. To examine the potential effects of time on balance control strategies, outcomes during the first 30seconds were compared to the last 30seconds.ResultsCorrelLR values did not differ across postures (AP: p=0.395; ML: p=0.647). Further, there were no main effects of time on CorrelLR (AP: p=0.976; ML: p=0.105). A significant posture-time interaction was observed in the ML direction (p=0.045) characterized by 35% decreases in CorrelLR over time for stooping (p=0.022).ConclusionThe dominant controllers of sway (i.e., AP: ankle plantar/dorsi flexors; ML: hip load/unload mechanism) are similar across quiet stance stooping, and crouching. Changes in ML control strategies over time suggests that fatigue could affect prolonged stooping more so than crouching or standing.



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