Comparison of isokinetic peak force and work parameters in youth with and without mental retardation

Purpose: The purpose of this study was to compare isokinetic knee (flexion and extension) strength of nondisabled youth (ND; 15 males, 15 females; mal es = 12.7 +/- 2 yr; females = 13.4 +/- 2 yr) and youths with mental retarda tions (MR, 17 males + 13 females; male = 14.7 +/- 2 yr; females = 13.6 +/- 2 yr). Methods: Subjects were evaluated on a Kin-Con isokinetic dynamometer at a speed of 60 degrees.s(-1). Parameters measured were peak torque (PT), time to PT, angle of PT, total work (W), and PT hamstrings/quadriceps (HQ) ratio. Peak torque was also corrected by weight (BW) and body mass index ( BMI). Peak torque, time to peak torque, angle of peak torque, and total wor k were analyzed using a 2 x 2 x 2 (groups x gender x muscle) repeated measu res analysis of variance (MANOVA). Flexion/extension ratios, BMI, and BW we re analyzed by separate 2 x 2 (group x gender) analyses of variance. Result s: Results of this study suggest that: 1) while gender differences are appa rent in the ND population they are not evident in individuals with MR; 2) k nee extension strength is higher for ND youth, thus causing lower PT HQ rat ios when compared with those in youth with MR; 3) angle of PT and time to P T were similar among groups; and 4) total work performed is lower in indivi duals with MR. Conclusions: It was concluded that parameters of strength pr oduction in individuals with MR are not consistent and do not follow the sa me pattern as their nonretarded peers.