SHORT TERM (24 HOURS) AND LONG TERM (1 YEAR) ASSESSMENTS OF RELIABILITY IN OLDER ADULTS: CAN ONE REPLACE THE OTHER?

There may be some individuals who do not adapt favorably to an exercise stimulus. This is most commonly determined by assessing the error of the measurement across two separate testing sessions separated by a short period of time. It has been recommended that this error be assessed over the same time frame as the intervention. We examined the 24-h test-retest reliability (n=18, aged 42 to 64 years) of forearm muscle thickness, handgrip strength, and “muscle quality” and compared that to the reliability observed when visits are separated by 1-year (n=80, aged 60 to 79 years). The measurement errors were greater in all measured variables following test-retest separated by 1-year than the test-retest separated by 24-hours. Our findings suggest that a time-matched control group is likely important to fully capture the error of the tester as well as the error associated with random biological variability within a timed intervention.