Relationship Between Performance-based and Self-report Measures of Physical Function in Resistance Trained Older Adults

Significance: By the year 2030, persons 85 years or older will be the fastest growing segment of the population, and the number who are 65 years or older will reach 70 million in the United States (ACSM, 1998). Because of this dramatic shift in national demographics, it is important to identify effective methods of assessing the physical capabilities that are necessary for functional independence among older adults. This study assessed the level of physical function and investigated the relationship between performance-based and self-report measures of physical functioning among independent older adults. Design: A cross sectional design was used. Twenty (20) male and twenty five (25) female subjects ranging in age from 58-74 years volunteered to participate. All study subjects had participated in at least 40 weeks of resistance training prior to testing and, as a result, were a high functioning group. Each subject completed three different tests: (1) the Continuous Scale Physical Functional Performance Test - a valid and reliable performance-based measure of physical function, (2) the Human Activity Profile (HAP), and (3) the Medical Outcomes Survey Short Form (SF-36) questionnaire. Pearson correlation coefficients and univariate linear regression were used to determine the relationships that exist between performance-based (CS-PFP) and self-report (SF-36 and HAP) measures of physical function. Results: Results confirmed that the study sample functioned at a high level when compared to other groups reported in the literature. Overall, there were a number of self-report subscales that significantly correlated to the CS-PFP Total score (average of all CS-PFP subscale scores), but the SF-Physical Functioning (SF-PF) subscale score was the single best self-report predictor (r=.692, p=.000, adj. r²=.466) of performance-based physical function of all of the SF-36 and HAP subscales that were considered. These results suggest that the SF-PF subscale is an acceptable self-report indicator of physical functional ability for high functioning older adults such as this sample when resources, time, and money are not readily available for performance-based testing. However, results also suggest that performance-based measures should be used whenever possible since SF-PF accounted for only 47% of the variance in CS-PFP Total.
Keyword(s): assessment, older adult/aging issues, performance