Effect of damp on isokinetic measurements

Meaningful use of isokinetic data requires understanding potential sources of variation and error. The purpose of this study was to examine one possible source of variation: the effect of recorder damp settings on Cybex II torque tracings. The effect of damp settings 0 through 4 at speeds of 30 degrees/sec and 75 degrees/sec was assessed by dropping loads of 13.65 kg and 36.85 kg attached to a lever arm of 30.5 cm on a Cybex II. The effect of damp settings at 180 degrees/sec was examined with the same weights at damp settings 2 and 4. Increasing damp resulted in 1) a decrease in amplitude of the entire torque curve and a decreased measurement of peak torque and 2) a shift of the torque curve to the right (later in time). The data underscore the need to record and to report the damp settings used during isokinetic testing.