UNH Research Shows Elderly Women Can Increase Strength But Still Risk Falls
Oct. 23, 2008

Decline in muscle function appears to be more related to a decline in physical activity than a natural part of the aging process. While older women can increase muscle strength as much as younger women can, they are less capable of making gains in muscle power (force/time), which is necessary to reduce fall risk and improve the ability to perform activities of daily living. Those are the findings of University of New Hampshire assistant professor of exercise science Dain LaRoche.

Researchers looked at strength gains of inactive older women and inactive younger women after both groups participated in an eight-week training regime.

While the two groups increased similar percentages of strength, the older group was far less effective in increasing power, which is more closely related to preventing falls, researchers aid. Preventing falls, which occur in 40% percent of people over 65 and are the top reason for injury-related emergency room visits, is the driving force behind LaRoche's research agenda.

LaRoche compared the initial strength of 25 young (18 – 33) and 24 old (65 – 84) inactive women then had both groups participate in resistance training on a machine that targeted knee extensor muscles, which are critical for walking, stair-climbing, or rising from a chair.

After eight weeks of training, the older group not only increased their strength by the same percentage as the younger group, they achieved gained strength similar to a control group of young inactive women. But the older group's ability to increase power – force over time – was significantly less than the younger group's; the elderly women saw only a 10% increase in power versus the younger women's 50% increase.

"It's somewhat troublesome that these older individuals had a reduced capacity to increase performance that's so closely associated with falls," says LaRoche. It seems that the key to muscle power in the elderly is to maintain it over the lifespan rather than try to develop it later in life, he says.

Acknowledging that the type or frequency (six sets, three times per week) of his training protocol may have affected the older group's ability to make gains in power, LaRoche is continuing to research older women's capacity to develop muscle power.

The research was published in the journal Medicine & Science in Sports & Exercise (Med Sci Sports Exerc. 2008: 40:1660-1668). An abstract of the research, "Elderly Women Have Blunted Response to Resistance Training Despite Reduced Antagonist Coactivation," is online at: http://www.chhs.unh.edu/docs/kin/LaRocheDP.pdf.

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