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Effect of age on muscle activation and twitch properties during static and dynamic actions

Authors

  • Melissa R. Wilder BExSc(Hons),

    1. Exercise and Sports Science Laboratories, School of Human Movement Studies, Charles Sturt University, Building N1, Panorama Avenue, Bathurst, New South Wales 2795, Australia
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  • Jack Cannon PhD

    Corresponding author
    1. Exercise and Sports Science Laboratories, School of Human Movement Studies, Charles Sturt University, Building N1, Panorama Avenue, Bathurst, New South Wales 2795, Australia
    • Exercise and Sports Science Laboratories, School of Human Movement Studies, Charles Sturt University, Building N1, Panorama Avenue, Bathurst, New South Wales 2795, Australia
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Abstract

In this investigation we examined age-associated changes in peak torque, voluntary activation levels, and potentiated twitch properties of the knee extensors during isometric (ISO), shortening (SHO), and lengthening (LEN) actions in 18 young subjects (19–27 years) and 12 elderly subjects (64–77 years). Peak torque was lower for the elderly subjects under the ISO (−31%) and SHO (−28%) conditions (P < 0.05); however, the loss in LEN peak torque in the elderly was less marked (−17%) (P > 0.05). Voluntary activation levels within and between groups were not significantly different and ranged between 96.8% and 98.9% (P > 0.05). Peak twitch torque and some temporal twitch characteristics were altered with age (P < 0.05), but such changes were similar across all muscle actions (P > 0.05). These data suggest that the attenuated reduction in LEN muscle strength associated with age is probably not related to contraction-specific changes in voluntary activation levels or potentiated twitch properties. Muscle Nerve, 2009

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