The reliability of upper- and lower-extremity strength testing in a community survey of older adults

Objective: To examine the stability (test-retest reliability) of strength measures in older adults obtained by nontherapist lay examiners by using a hand-held portable muscle testing device (Nicholas Manual Muscle Tester). Design: A prospective relational design was used to collect test-retest data for 1 male subject by using 27 lay raters who completed intensive training in manual muscle. Setting: Data were collected from older Mexican-American adults living in the community. Participants: Twenty-seven lay raters who completed intensive training in manual muscle testing for a field-based assessment and interview of older adults and 63 Mexican-American subjects completing wave 4 of the Hispanic Established Populations for the Epidemiologic Study of the Elderly. Interventions: Training involved reviewing a manual describing each testing position followed by approximately 6 hours of instruction and practice supervised by an experienced physical therapist. Lay raters then collected test-retest information on older Mexican-American subjects. Main Outcome Measure: Stability (test-retest) for a portable manual muscle testing device. Results: Intraclass correlation coefficients (ICCs) were computed for the 27 lay raters examining 1 male subject (2 trials) and 12 lay raters assessing 63 older Mexican-American adults (1 practice and 2 trials recorded). The ICC values for the first 27 lay raters ranged from.74 to.96. The ICC values for the latter 12 lay raters ranged from.87 to.98. No differences were found in ICC values between male or female subjects. Conclusions: Stable and consistent information for upper- and lower-extremity strength was collected from the older adults participating in this study. The results suggest reliable information can be obtained by lay raters using a portable manual muscle testing device if the examiners receive intensive training.