Women who exercise throughout life may keep their muscle power as they age, a new study suggests.
For the study, researchers from Ball State University in Muncie, Indiana, examined muscle strength, power and the size and type of muscle fibres in the thighs of three groups of women.
Fibres decline with age
Seven women in one group were over 70 and had exercised regularly for nearly 50 years. The second group had 10 women who averaged 25 years of age and also worked out regularly. The third group comprised 10 women over 70 who did not exercise regularly.
The over-70 exercisers had more of the "slow-twitch" muscle fibres, the kind of fibres that add to endurance and efficient energy use than women who didn't exercise and young women who did, the researchers found.
Compared with younger exercisers, both groups of older women had smaller fast-twitch fibers, the study showed. That type of muscle contributes more to power than endurance.
Typically, its functioning declines with age.
Findings are 'unique'
The older exercisers preserved more fast-twitch power than women who didn't exercise. They also had more power in slow-twitch muscle fibres, researchers added.
The report was published in the Journal of Applied Physiology.
Scott Trappe, professor and director of BSU's Human Performance Laboratory, was one of the leaders of the study.
His team said the findings "are unique and provide new insights into aging skeletal plasticity in women on the myocellular level," according to a journal news release.
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