The reproducibility of multi-joint isokinetic and isometric assessments ina healthy and patient population

Design. Test re-test reliability design. Objective. To determine a reproducible protocol for lower limb simultaneous multi-joint assessments on a healthy group of subjects and a patient group with patellofemoral pain syndrome. Background. Although single joint assessment with isokinetic dynamometers h as been utilised for many years in knee rehabilitation, simultaneous multi- joint assessment has not attracted comparable attention. Methods. Twenty healthy volunteers mean age 30.6 years and 16 patients with patellofemoral pain syndrome mean age 29.6 years performed isometric maxim um voluntary contractions and concentric isokinetic contractions of the low er limb. Data were collected on three separate days for resultant extension /flexion peak torque, average power and total work which were analysed usin g intraclass correlation coefficients with a 95% level of confidence. Results. In healthy subjects, intraclass correlation coefficients estimates were greater than or equal to 0.75 for isokinetic peak torque and > 0.83 f or average power and total work. The intraclass correlation coefficients es timate for isometric peak torque extension was 0.82. In the patient group, intraclass correlation coefficients estimates were > 0.82 for isokinetic pe ak torque and greater than or equal to 0.75 for average power and total wor k. The intraclass correlation coefficients estimate for isometric peak torq ue extension was 0.89. Discarding the first session's data for both groups improved the intraclass correlation coefficients estimates for virtually al l assessments. Conclusions. This study has demonstrated high reproducibility of lower limb multi-joint testing for peak torque, average power, and total work on heal thy subjects and then has employed the protocol to demonstrate similarly hi gh reliability on a patient group. It has also highlighted the need for a p ractice session before the data can be said to be reliable. (C) 2000 Elsevi er Science Ltd. All rights reserved.