Hand-held myometry.

In their two recent articles, Vander Ploeg et al provided information that should prove useful to clinicians who use hand held dynamometers. The reference values presented by the authors provide a much needed basis for establishing the normality of a patient's strength.' The ratios between the forces measured during make tests and break tests may, as the authors suggest, be diagnostically discriminating.2 The purpose of this letter is to provide some additional information relevant to reference values and make test and break test forces. Reference values, based on hand held dynamometer measurements, have been published before. The values (which were for make tests rather than break tests) were limited, however, to 10 upper extremity muscle groups of healthy young women.3 Comparisons of the ratio of break test forces to make test forces have also been published previously. The ratios, however, are higher than those reported by Vander Ploeg et al. Specifically, Bohannon reported that the force measured at the elbow during break tests was a mean 1-3 times as great as that measured during make tests. The ratio was demonstrated in both healthy subjects4 and on the nonparetic side of patients with stroke.' On the paretic side of the stroke patients, the break test to make test force ratio was a mean 1-7 to 1-0. Why the ratios reported by Bohannon are so different from those ofVander Ploeg et al is uncertain. What I believe is certain is that hand held dynamometry is a much underused clinical measurement procedure and that further research needs to be conducted on the procedure. RICHARDW BOHANNON The University of Connecticut, School ofAllied Health Professions, Box 0-JO, 358 Martsfield Road, Storrs, CT USA