KNEE EXTENSOR AND FLEXOR STRENGTH IN ELDERLY WOMEN AFTER RECENT HIP FRACTURE - ASSESSMENT BY THE CYBEX-6000 DYNAMOMETER OF INTRA-RATER INTER-TEST RELIABILITY

The reliability of knee extensor and flexor strength measurements was assessed in 20 women (age 68-88 years) who had experienced a hip fract ure two to four weeks before but who mere other,vise healthy, Using th e Cybex 6000 isokinetic dynamometer, isokinetic knee extensor and flex or strength (peak torque, total work and power) at 30 and 120 degrees/ second and isometric knee extensor and flexor strength (peak torque) w ere measured by the same examiner in both legs, successively, on four separate days within one week, Compared with the non-involved leg, the median reduction in peak extensor and flexor torque of the involved l eg was 50% (p < 0.001), With the protocol used, no significant change in muscle strength occurred during the test period, Individual coeffic ients of variation (CVs) were calculated for each muscle strength vari able, Depending on whether torque, work or power mere measured, the me dian CVs of extensor and flexor strength measurements of the non-invol ved leg ranged from 5.6-14.6% and 10.8-28.6%, respectively. The corres ponding CVs for the involved leg were 10.9-22.1% and 13.0-35.2%, Subst antial variability between individual CVs were found for all strength variables, In conclusion, although muscle strength measurements may be applicable when comparing larger groups of hip fracture patients, the large CVs may be a limitation in monitoring individual patients, This finding should be taken into consideration when planning individual t raining programmes.