BACKGROUND AND PURPOSE

An observed consequence of aging is a decline in muscle performance that includes a loss in both muscle strength and muscle power. This decline can lead to loss of function and independence and is a predictor of disability in older adults. Although the 2008 Physical Activity (PA) Guidelines for Americans provides a guideline for muscle strengthening, there is no evidence that performing muscle strengthening 2 times a week for all major muscle groups is related to better performance on measures known to be important factors in development or progression of frailty in older adults. The purposes of this study were to assess muscle-strengthening and aerobic PA behaviors in older adults and to determine the relationship between the PA behaviors and physical performance measures.

METHODS

This was a cross-sectional study of 85 community-dwelling, ambulatory adults (50 women, 35 men) with a mean (standard deviation) age of 67.5 (5.6) years. All used an internet-based survey, TREST (Tracking Resistance Exercise and Strength Training), to report muscle-strengthening and aerobic PA behavior. Physical performance measures of grip strength, 10-m walk test (10-MWT), five-time sit-to-stand test (FTSST), and stair climb test (SCT) were obtained following completion of the survey. Participants were grouped by whether they met 2008 PA Guidelines for (1) muscle strengthening 2 or more days per week, (2) muscle strengthening 2 or more days per week using all major muscle groups, or (3) 150 minutes or more per week of aerobic moderate to vigorous physical activity. Comparisons of physical performance measures were conducted between participants who met and did not meet guidelines using multivariate analyses. Significant multivariate results were followed with one-tailed t tests.

RESULTS AND DISCUSSION

The participants meeting muscle strengthening 2 or more days per week performed significantly better on measures of grip strength and SCT. Only 27% of participants met the more stringent-strengthening guideline of 2 or more days per week using all major muscle groups, and these individuals performed significantly better on the SCT and FTSST. The participants meeting the aerobic activity guideline performed significantly better on the SCT, the FTSST, and the 10-MWT.However, participants who met both the strengthening and aerobic activity guidelines performed significantly better on all 4 physical performance measures than participants who met neither of the guidelines.

CONCLUSIONS

Meeting guidelines for both aerobic and muscle-strengthening activities may be the most effective way of preserving muscle strength, muscle power, and gait velocity in older adults, but this conclusion must be tested with an intervention study.