The effect of strength training on control of force in older men and women.

BACKGROUND AND AIMS: Age-related structural alterations in motor units and consequential functional manifestations are asserted to underlie the decline in the ability to finely grade, or control, muscular force in upper extremity musculature of older adults. Functional activities requiring appropriately graded muscular action, such as control of balance, may therefore be negatively affected by these changes. Recent investigations of smaller intrinsic hand muscles have suggested that strength training may attenuate the normal age-related decrease in strength and control of force resulting in increased strength and control. The effects of strength training on the larger, more powerful, anti-gravity muscle of the quadriceps, where age-related changes are noted earlier, are unknown. Thus, the purpose of this study was to assess the effects of 12 weeks of high intensity strength training on strength and the ability to control muscular force in untrained older adults.
METHODS: Twenty-two subjects aged 59-83 years (11 males, 11 females) were compared to 5 untrained, age-matched controls 58-76 years of age (3 females, 2 males). Maximal isometric knee extensor strength and control of force at 30, 60, and 90% of maximum were measured at 0, 6, and 12 weeks.
RESULTS: Significant increases in quadriceps strength were noted in the exercise group but neither group showed a change in the ability to control sub-maximal forces.
CONCLUSIONS: These findings suggest that high intensity strength training may be efficacious for improving strength but does not improve the ability to control sub-maximal isometric forces.