Frailty is a common risk associated with aging and is predictive of many poor outcomes. Much research exists that demonstrates the utility of physical exercise to prevent frailty, but it is unclear which forms of exercise are most effective for older adults at risk for frailty. A forthcoming article presents a study that compared the effects of two types of resistance training—strength training and power training—on a group of community-dwelling older adults at risk for frailty.
The researchers recruited 69 participants, ranging in age from 70 to 84. Each participant was considered at risk for frailty for meeting one or two of five criteria used to assess frail risk, such as unintentional weight loss or low physical activity level. Participants were randomly assigned to either a strength training group, a power training group, or a control group.
In power training, the person exercising performs initial lifting, pushing or pulling (usually lifting a weight or performing another type of resistance training) as rapidly as possible. In strength training, this part of the exercise is done at a steadier, slower velocity. Previous research has not made it clear which form is more effective against frailty in older adults. However, the authors hypothesized that some of the conflicting findings in earlier research may have resulted from vitamin D3 deficiency on the part of participants. Vitamin D3 deficiency is common in older adults and appears to be related to physical strength and performance. Participants were assessed for Vitamin D3 deficiency; those with low levels were provided with 2,000 IU of vitamin D3 daily, while those with normal levels were given 1,000 IU.
Each of the training groups participated in 24, twice-weekly training sessions that began with a warm-up session and balance exercise. Then each group performed either the power or strength training portions, doing exercises such as chest presses and toe-raises under supervision. The power training group did these in a fast, explosive fashion, while the strength training was done at a slower, more natural pace. Participants were encouraged to maintain their normal level of daily activity for the duration of the program.
The two training groups and the control group were compared on several different measures, including the Short Physical Performance Battery (SPBP), a scale that has been found to be predictive of health outcomes, and which consists of balance, walking, and sit-to-stand repetitions. The SPBP was the only measure to show any difference between groups, with both the power training and strength training groups showing significant improvements relative to the control group. There was no significant difference between the two physical training groups.
The results of the study did not indicate that one form of training was superior to the other, but both forms improved the physical performance of participants. However, two participants left the power training group due to adverse reactions (arthritis pain and vertigo), while none dropped out of the strength training group for exercise-related reasons. Thus, lower-velocity strength training may be more acceptable to many individuals, while giving similar benefit as power training.
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