Identifying Criterion Fitness Scores Associated With Maintaining Functional Mobility and Independence
As is typical in the process of establishing criterion-based standards, a combination of processes—subjective reasoning, data-based statistics, and literature review—was involved in arriving at the recommended fitness standards (cut-point scores) for the SFT test items that would be associated with the ability (or projected ability) to function independently in later years. More specifically, fitness standards were developed based on the fitness scores achieved by the 2,140 moderate-functioning participants in the previously described normative database, with adjustments made as needed to reflect other relevant information from the literature regarding anticipated age- and gender-related patterns of decline over the 30-year period from the 60s to the 90s. Naturally, the 3,126 study participants who are rated as high functioning would also meet the criteria for independent functioning in later years. However, fitness scores for this group of study participants were not considered in the analysis when establishing minimum fitness standards for independent functioning because it was assumed their performance, being much higher than what is needed to meet minimum requirements, would have an inflationary effect on the fitness standards being proposed.
The strategy followed in arriving at the recommended fitness standards for older adults as presented in chapter 5 ( volved three stages, with the first step being to set fitness standards for 90- to 94-year-olds, utilizing the actual scores obtained by the moderate-functioning (independent) 90- to 94-year-old participants in the normative study database. This was considered a logical first step since the goal of maintaining the level of fitness needed for independent functioning had already been met by this group. Because there is no evidence in the literature suggesting that thresholds for maintaining physical independence should be different for men than for women, the same fitness standards are proposed for those over 90 for both sexes on all test items, standards that are based on the average scores obtained by moderate-functioning 90- to 94-year-old male and female study participants, but with some rounding off and minor smoothing of numbers to make them consistent with SFT scoring procedures and convenient for use by the public.
Previous reports suggest that the proposed standards for the 90- to 94-year-olds are reasonable and in line with other findings concerning the level of fitness needed for independent functioning. The 400-yard (366 m) standard for 90- to 94-year-olds on the 6-minute walk, for example, is within the range of the 360- to 600-meter recommendation that has been previously proposed as the minimum walking distance needed to function independently—that is, to be able to navigate within the community to do one’s own shopping and errands (Cohen, Sveen, Walker, & Brummel-Smith, 1987; Lerner-Frankiel, Vargas, Brown, Krusell, & Schoneberger, 1986). Also, the 400-yard standard on the 6-minute walk is close to the quarter-mile (440 yard) criteria used by Medicare as a cut point for defining mobility limitation and disability (U.S. Department of Health and Human Services, 2006). The proposed fitness standard of 8.0 seconds for 90- to 94-year-olds to complete the 8-foot up-and-go test is similar to, but appropriately below, the 8.5-second cut point that has been identified as a predictor for falling in older adults, using the same testing protocol (Rose et al., 2002). Performing below the 8.5 cut point for predicting falls is an especially important consideration, given that falls and fall-related injuries are a major cause of loss of independence and escalating health care costs (Centers for Disease Control and Prevention,
The second stage in the process involved determining appropriate fitness standards for age groups younger than 90 based on how much anticipated physical decline needed to be planned for over the 30-year period between the ages of 60 and 64 and 90 and 94. It was important that standards be set high enough to allow people to experience normal rates of age-related decline and not progress below that required for independent functioning at age 90. In estimating the rate of decline that needed to be planned for on each of the fitness variables, we first considered the actual scores obtained by the 2,140 independent-functioning participants in the normative database, then we calculated the percent decline seen over the 30-year period from 60 to 64 and 90 to 94. Next, we made adjustments in this figure (percent decline) based on information from the literature showing a greater rate of decline (approximately 1.25 as great) when performance is tracked longitudinally (in the same people from one age to the next) versus cross-sectionally, which occurred in the normative study when different age groups were measured at the same time. Therefore, the standards presented in table 5.5 for 60- to 64-year-olds reflect an anticipated rate of age-related decline that is approximately 1.25 times greater than what was observed in the normative study participants. See Rikli and Jones (2012) for additional
Once fitness standards were developed for the oldest (90 to 94) and youngest (60 to 64) age groups, we established standards for the remaining in-between ages based on the best knowledge available concerning patterns of declines across these age groups, paying particular attention to the fact that the rate of decline tends to be greater for men than women (Doherty, 2003; Hughes et al., 2001); that lower-body strength tends to decline faster than upper-body strength (Paterson, Jones, & Rice, 2007; Vandervoordt, 2002); and that there is a well-recognized curvilinear pattern of age-related decline, with an acceleration in decline in later years (ACSM, 2009; Doherty, 2003; Macaluso & De Vito, 2004; Paterson et al., 2007; Vandervoordt, 2002).
As mentioned previously, the ultimately proposed standards of fitness for all age groups reflect rounded-off numbers to make them consistent with SFT scoring procedures and to make them more user-friendly and convenient for use by practitioners who work with older adults and by older adults themselves. All standards for the chair stand, arm curl, and step test have been reported in whole numbers to be consistent with the SFT scoring instructions for these tests, with standards for the 6-minute walk reported in 5-yard increments, also consistent with scoring instructions on the SFT.