Although short-term randomized clinical trials in older persons have shown that structured PA programs improve performance on various measures of physical function (3
), data are needed on long-term follow-up, and there has been a call for more research with populations that have compromised function (16
). The current article examines data collected 2 years after older adults with compromised physical functioning had terminated the 12-month structured PA intervention of the LIFE-P. We were able to recruit 75% of the original randomized participants in both the PA and the SA treatment arms of the WFU field center for 36-month testing (). There were no significant baseline differences between those in the original sample who either did or did not participate when examining comorbidities, demographic characteristics, or level of PA. Although these groups did differ on baseline gait speed and SPPB scores, it was those who did not participate that had slightly higher functioning at baseline. Mindful of the limitation in sample size, these patterns do offer support for the external validity of the study results.
It was encouraging to find that at the 36-month follow-up, participants in the PA group continued to self-report more moderate PA and had higher SPPB scores than those who had been randomized to the SA group. Although the results for gait speed in the 400-m walk did not reach conventional levels of statistical significance, the results were in the expected direction, favoring the PA group. Note that between-group differences for the SPPB and the 400-m walk were constant over time, indicating that the change in the size of the p values from baseline to 36 months was due to a reduction in statistical power due to decreasing cell sizes. Patterns in participants’ major mobility disability status—failure to complete the 400-m walk—also warrant comment. Of those who had successfully completed the 400-m walk at both the 6- and the 12-month assessment, 58.2% of those in the PA group successfully competed the 400-m walk at the 36-month assessment, whereas the percentage was 49.0% in the SA group. Also, whether one examines differential death rates between groups or persistent disability, trends favor the PA group.
In a prospective epidemiological study, the Women’s Health and Aging Study (WHAS), Simonsick and colleagues (17
) collected SPPB data on walkers versus nonwalkers—defined as walking either more than or less than eight blocks each week, respectively. At the 1-year assessment visit, SPPB scores of walkers declined by approximately 0.1 points compared with nonwalkers who experienced a decline of approximately 0.6 points (p
= .01). Based on their PA data, participants within the SA group of the current study were more similar to the walkers than to the nonwalkers in WHAS. Specifically, on average, at 36 months, the SA group in the LIFE-P reported 99.3 minutes of moderate PA each week. Even though the PA group was only doing an additional 66.1 minutes of moderate PA per week at 36 months compared with the SA group, it does represent an increase of 66.5%. As noted in recent PA guidelines for older adults (16
), it takes less of a stimulus to produce meaningful health benefits in older adults who have compromised function than in the general population.
The data reported by Simonsick and colleagues (17
) in combination with the current findings are encouraging. Whereas they suggest that even though low-level, free-living PA among older adults with compromised function is protective against further decline, a more formal intervention such as the LIFE-P can provide added benefit, which can be maintained up to 2 years after treatment has been terminated. This is an area of study that warrants further attention. It is also important to emphasize that the LIFE-P intervention was state of the art and included a 10-week group-meditated behavioral component that has been found to be superior to traditional exercise programming in enhancing long-term rates of adherence (18
To our knowledge, the current study data are unique. Rarely is information reported on extended posttreatment follow-up in PA intervention trials. However, it is important to keep in mind the limited sample size due to having data available from only one of the four clinical sites. This sample size restriction reduced statistical power and impaired our ability to examine potential moderators of treatment effects. The LIFE-P was conducted with the intent of providing guidance on study design for a large multicenter trial. Study funds were not available for posttreatment follow-up; however, this study was supported internally at Wake Forest because we felt that these data could inform the design of future studies.