Intrarater and interrater reliability of strength measurements of the biceps and deltoid using a hand held dynamometer.

This study reports the intrarater and interrater reliability of measurements for elbow flexion (biceps) and shoulder abduction (deltoid) in 27 normal subjects. Testing was done by two physical therapy examiners. For each muscle group tested, the first series of three tests were administered according to the general guidelines described in the dynamometer administration manual and then repeated with increased stabilization procedures (i.e., examiner elbow stabilized against the anterior superior spine). Intrarater and interrater reliability were highest when tested with the examiner elbow stabilized. Intrarater reliability coefficients were in an acceptable range both with and without additional stabilization (0.833 to 0.957) but interrater reliability coefficients were more variable, ranging from a low of 0.518 to a high of 0.840. Mean muscle strength measurements were significantly different between the two examiners. More studies are needed to improve interrater reliability when estimating muscle strength with the hand held dynamometer.J Orthop Sports Phys Ther 1988;9(12):395-398.