Factors relating to gender specificity of unloading-induced declines in strength

Authors

  • Michael R. Deschenes PhD,

    Corresponding author
    1. Department of Kinesiology & Health Sciences, The College of William & Mary, Williamsburg, Virginia 23187-8795 USA
    2. Program in Neuroscience, The College of William & Mary, Williamsburg, Virginia 23187-8795 USA
    • Department of Kinesiology & Health Sciences, The College of William & Mary, Williamsburg, Virginia 23187-8795 USA
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  • Raymond W. Mccoy PhD,

    1. Department of Kinesiology & Health Sciences, The College of William & Mary, Williamsburg, Virginia 23187-8795 USA
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  • Katherine A. Mangis BS

    1. Program in Neuroscience, The College of William & Mary, Williamsburg, Virginia 23187-8795 USA
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  • Grant support provided by: The Borgenicht Program for Aging Studies and Exercise Science, and the National Institutes of Health (9R15 AR060637-03).

Abstract

Introduction: This investigation aimed to: (1) confirm whether women were more vulnerable to the negative neuromuscular adaptations elicited by muscle unloading and if so, (2) determine which physiological mechanism(s) explain those gender-related differences. Methods: Healthy young men (20.7 ± 0.3 years) and women (20.3 ± 0.3 years)—(N = 12/group)—participated by completing neuromuscular functional tests before and after 7 days of unloading. Results: During isokinetic testing of peak torque, work performed, and power, women displayed significantly (P ≤ 0.05) greater declines in performance than men at 1.05 and 2.09, but not 0.53 rads/s. During maximal isometric contractions, women experienced greater strength decrements. Similar gender-specific adaptations to unloading were found in EMG activity, but not muscle mass, neuromuscular transmission, or force relative to EMG. Conclusions: Women are more susceptible to the adaptations of muscle unloading, and disturbances in neural drive from the central nervous system are probably responsible. Muscle Nerve 46: 210–217, 2012

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