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Movement Accuracy Changes Muscle‐Activation Strategies in Female Subjects During a Novel Single‐Leg Weight‐Bearing Task
Author(s) -
Madhavan Sangeetha,
Shields Richard K.
Publication year - 2009
Publication title -
pmandr
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.617
H-Index - 66
eISSN - 1934-1563
pISSN - 1934-1482
DOI - 10.1016/j.pmrj.2009.01.002
Subject(s) - coactivation , physical medicine and rehabilitation , weight bearing , squat , medicine , rehabilitation , task (project management) , electromyography , physical therapy , displacement (psychology) , psychology , surgery , psychotherapist , management , economics
Objective Understanding of how female subjects learn to move accurately during a resisted weight‐bearing task is limited. The purpose of this study was to examine the muscle activation patterns used by female subjects in learning a novel single‐leg squat (SLS) task under visual and nonvisual conditions. Design Prospective training study. Setting University research setting. Participants Ten healthy young female participants. Intervention Subjects tracked a sinusoidal target (knee displacement) during a resisted SLS exercise during the course of 4 days, under eyes open (EO) and eyes closed (EC) conditions with the use of a custom‐designed weight‐bearing exercise device. Main Outcome Measurement The accuracy of performance in tracking the target and electromyographic activity (EMG) of 5 muscles around the knee were monitored. Results Subjects improved their accuracy of performance by day 2 (40% decrease in error) and retained the accuracy on day 4. Error during the EC condition was 3 times greater than EO condition. Quadriceps‐to‐hamstrings coactivation ratio increased with the improved accuracy from the learning. Absence of visual feedback was accompanied by a decrease in the quadriceps‐to‐hamstrings coactivation ratio for this task. Conclusion The muscle synergistic activity around the knee changes as the accuracy of the task improves during a resisted weight‐bearing task. This activation pattern represents a feed forward control plan that the central nervous system adopted to optimize accurate weight‐bearing knee displacement. Rehabilitation specialists should consider manipulating the visual feedback and accuracy of performance when developing weight‐bearing rehabilitation training protocols to improve neuromuscular control in female patients.