Decline in muscle function due to lack of physical activity not aging

Recent study results suggest that the decline in muscle function that occurs with aging is caused by a decline in physical activity and not the aging process.

Researchers at the University of New Hampshire studied 49 inactive women, 25 of which were aged 18-33 years and 24 were aged 65-84 years. Participants participated in an 8-week-long strength training regime or were assigned to a control group.

Results showed that the strength training program led to similar increases in muscle strength in the young and old women.  Thus suggesting that muscle function decline is caused by a decline in physical activity and not by the aging process.

However, whilst the program increased the muscle power of the older women by approximately 10%, the muscle power of the young women increased by approximately 50%. "Power is more important than strength for recovery from loss of balance or walking ability," says researcher Dain LaRoche, in a news release issued by the University of New Hampshire.  "It's somewhat troublesome that these older individuals had a reduced capacity to increase performance that's so closely associated with falls." LaRoche says that this suggests that the key to maintaining muscle power is to try and maintain it throughout life rather than try to develop it in old age.

LaRoche DP, Roy SJ, Knight CA, Dickie JL.Elderly Women Have Blunted Response to Resistance Training Despite Reduced Antagonist Coactivation. Medicine & Science in Sports & Exercise. 2008;40:1660-1668.