TESTING VERSUS TRAINING EFFECTS ON IRM STRENGTH ASSESSMENT IN OLDER ADULTS909

Abstract

Recent studies (Fiatarone et al., 1990; 1994) have reported large strength increases in older adults as a result of fairly short-term resistance training. However, what has not been reported in these or similar studies is the reliability of 1RM strength testing protocols for older adults. Reliable baseline measures should have high test-retest correlations and nonsignificant trial-to-trial increases (Baumgartner & Jackson, 1995). The purpose of this study was to determine the number of trials necessary to achieve reliable 1RM strength measures for older adults on four resistance exercises--leg press, knee extension, chest press, and seated row. Forty-two older adults (M age = 71.9) received one day of practice and three 1RM tests, 2 to 5 days apart, on each of the four measures. Significant increases between trials 1 and 2 (p <.001), but not between trials 2 and 3 indicate that two test trials are required to achieve stable measures. Intraclass reliability values for this procedure were.98 (leg press),.97 (knee extension),.97 (chest press), and.98 (seated row). A comparison of pretest with subsequent posttest scores following a 10-week high intensity training program (60-80% of maximum resistance) indicated that testing effects (trial 1 to trial 2 increases) accounted for a sizable proportion of total strength improvement on all measures--55.9% for the leg press, 42.5% for knee extension, 39.8% for the chest press, and 31.4% for the seated row. These results suggest the need for one practice and two test trials, utilizing trial 2 as the baseline measure, when assessing the magnitude of intervention effects in strength training studies on older adults.