Lifting ability and leg strength.

The purpose of this study was to determine the relationship between peak torques of lower extremity muscle groups and lifting ability with a floor-to-knuckle leg lift in a healthy person. Twenty-four healthy, young subjects between the ages of 20 and 40 participated in the study. Each subject was tested for 1) isokinetic peak torque of the knee extensors and flexors and hip extensors and flexors on a Cybex II dynamometer, 2) isometric lifting ability using a strain gauge dynamometer, and 3) maximum lifting ability using a box and free weights. The subjects used a squat technique and maintained a neutral spine position with a lordotic curve during the lifts. No significant correlations were found with the data analysis for the entire group. For 15 male subjects, the regression equations revealed a statistically significant correlation between isokinetic knee extensor peak torque (180 degrees /sec) and isokinetic hip extensor peak torque (30 degrees /sec) with both maximum lifting ability and isometric lifting ability. The regression equations were MAXIMUM LIFT = 46.1 + 0.92Q + 0.10H (F = 4.07, p < 0.05) and ISOMETRIC LIFT = 16.6 + 23Q + 1.05H (F = 6.32, p < 0.025) (Q: isokinetic knee extensor peak torque at 180 degrees /sec; H: isokinetic hip extensor peak torque at 30 degrees /sec). No statistically significant correlations were found for the nine females. These results indicate that in a healthy, young population, isokinetic knee extensor and hip extensor peak torque may be predictors of floor-to-knuckle leg lifting ability in males, but not in females. J Orthop Sports Phys Ther 1991;14(1):24-30.