ity. Upper-extremity muscle groups showed higher long-term stability than lower-extremity groups. The stability of test-retest measurements for most muscle groups was shown. Lower reliability of the left hip extensor measurements was concluded to be due to a lack of support of the leg while testing hip extensors. Stability measurements in paretic limbs was not found to be greater than in nonparetic limbs. The study concluded that HHD is a stable tool for measurement. It was suggested however, that support of the lower extremity during hip extensor tests, padding of the dynamometer end pieces, and use of a smaller, digital dynamometer might yield even more reliable results (5:458-465).
Wadsworth, Nielsen, Corcoran, Phillips, and Sannes (1992) studied interrater reliability of HHDs. One man and one woman were subjects; both had no neuromuscular deficits and a normal grade on manual muscle tests of five muscle groups. The raters were physical therapy students with previous HHD experience. Intra subject reliability was insured by an additional male rater who verified consistency of testing prior to the primary study. Four different raters tested five muscle groups of two subjects on a given day (14:74-81).
Although the sample size for this study was small and results may not generalize to a larger population, findings indicated that HHD reliability is affected by rater gender, body weight, and grip strength. Differences in torque values between muscle groups was demonstrated as expected; muscles were selected to demonstrate a wide range of strength. Interrater reliability was good for the female test subject; differences between female and male raters' mean torque values were minor. Findings were similar for most of the muscle groups for the male subject. However, stabilization was not found by female raters on two muscle groups which may have been due to rater body weight and grip strength. It was concluded that fema...