KNEE FLEXION TO EXTENSION PEAK TORQUE RATIOS AND LOW-BACK INJURIES INHIGHLY-ACTIVE INDIVIDUALS

The purpose of this study was to investigate for possible relationship s between knee flexion to extension peak torque ratios (F1/Ext(rat)) a nd low-back injuries in highly active males and females. Forty-eight m ale (age 25.9+/-4.5 years) and 41 female (age 27.3+/-2.6 years) compet itive rowers, and 20 male (age 26.6+/-6.0 years) professional ballet d ancers volunteered for the study. Each subject performed a test of lum bar and knee flexor flexibility, isokinetic dynamometry and completed a self-administered questionnaire. Flexibility was assessed by using t he sit-and-reach test. Knee flexion to extension peak torques were bil aterally monitored at the angular velocities of 1.04 and 4.19 rad . s( -1). The questionnaire was designed to obtain information regarding th e number of days off action (e.g., training, competition, and rehearsa ls), due to low-back injuries, for the 12-month period prior to testin g. Results revealed significant negative correlation coefficients betw een knee F1/Ext(rat), obtained at 1.04 rad . s(-1), and days off physi cal activity for oarsmen (r=-0.69; p<0.01), oarswomen (r=-0.62; p < 0. 01) and male dancers (r=-0.57; p<0.05). No such correlations were foun d for either knee F1/Ext(rat) obtained at the angular velocity of 4.19 rad . s(-1) or between the sit-and-reach test results and low-back in juries. A sub-group of 22 female rowers was re-tested after a 6-8 mont h period, during which a special hamstring strength training programme was introduced. The main conclusions were: a) the lower the F1/Ext(ra t) the greater the degree of low-back injury, b) at least in female ro wers, 6-8 months of hamstring strength training can contribute to a re duction of the incidence of low-back injury, and c) isokinetic assessm ent of quadriceps and hamstrings obtained at lower compared to higher angular velocities is more prognostic of low back injury.