Reliability of maximal static strength measurements of the arms in subjects with hemiparesis

Our objective was to evaluate the reliability of maximal strength measurements of live arm muscle groups and of strength ratios (paretic/non paretic) in subjects with poststroke hemiparesis.

The generalizability theory was used to estimate the reliability coefficients and standard errors of measurement of maximal strength for various combinations of trials and sessions and of strength ratios for one and two sessions. Grip maximal voluntary force and/or maximal voluntary torques exerted by flexor and extensor muscles at both the elbow and shoulder joints were measured in 17 subjects with poststroke hemiparesis. Multiple trials were performed by subjects during two sessions.

The results show that the reliability coefficients for the strength measurements were in the range of 0.81 – 0.97 with standard errors of measurements accounting for 4% to 20% of group means. For the strength ratios, the coefficients of generalizability ranged from 0.76 to 0.95 with standard errors of measurement equal to 6% to 19% of the group means.

The conclusions are that the maximal strength measurements of the arms in subjects with hemiparesis are reliable. The strength ratios are also reliable and can be used to quantify strength impairment.