POWER TRAINING IN OLDER ADULTS;MECHANISMS UNDERLYING CHANGE IN MUSCLE FUNCTION

Wake Forest University Health Sciences, Winston-Salem NC

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Abstract

DESCRIPTION (provided by applicant): Sarcopenia-the progressive loss of muscle strength, mass, and quality that accompanies the aging process-has serious health consequences for older adults. Decline in muscle strength is associated with functional decline and disability in older adults. Interestingly, muscle power (i.e., the product of muscle force and speed of movement) declines earlier and at a faster rate than muscle strength. It has been suggested that a) loss of lower extremity muscle power may have greater significance than loss of muscle strength, especially with regard to limiting certain activities of daily living, b) lower extremity muscle power is associated with physical function, while peak muscle power is predictive of functional limitations and disability in older adults, and c) muscle power, as opposed to muscle strength, represents the critical variable in situations where postural stability is challenged, e.g., a trip/slip. Traditional progressive resistance training (PRT) interventions, also referred to as strength training, have been shown to increase strength and power in older adults but to date, there is a dearth of information on power training in older adults. Studies that have incorporated faster movement speeds in a PRT intervention suggest that this type of intervention is feasible and that substantial improvements in strength and power are possible in older adults. However, these studies did not directly compare traditional PRT with power training. Therefore, it is unknown if power training leads to greater increases in strength and/or muscle power or whether power training is a more effective intervention to prevent disability and improve physical performance, as compared to traditional PRT. The primary goals of this pilot project are: 1) to examine the feasibility and safety of a 16-week lower extremity power training intervention in 45 older adults with mild to moderate self-reported disability, and 2) to obtain an estimate of the effect of power training on physical function, self-reported disability, body composition, muscle cell contractile function, and health-related quality of life, in order to determine variances and effect sizes for sample size calculations for a future, more definitive randomized trial. We hypothesize that in the context of a larger trial, power training will lead to similar improvements in lower extremity muscle strength, and will yield greater improvements in lower extremity muscle power, as compared to traditional PRT. Thus, power training could ultimately prove to be more effective in reducing disability and improving physical performance than traditional PRT.