Peak torque and total work relationship in the thigh muscles after anterior cruciate ligament injury.

The purpose of the present study was to 1) assess the relationship between the isometric and isokinetic peak torques (speed of movement 0, 60, 180 degrees /sec) and the total work output of multiple contractions (180 degrees /sec) of the quadriceps and hamstrings in 36 patients having a chronic anterior cruciate ligament (ACL) insufficient knee joint, and 2) determine the possible association of these muscle function parameters with the subjective and functional outcome of the ACL insufficient knees. At every test speed the Pearson product moment (r) and the Spearman rank (r,) correlation coefficients between the peak torque and the total work were highly significant for the quadriceps and hamstrings in the uninjured (r = 0.71-0.93, rs = 0.70-0.90) as well as in the anteriorly unstable (r = 0.82-0.89, rs = 0.79-0.86) knees. All correlation coefficients were higher at the highest speed (180 degrees /sec) of the isokinetic test (r = 0.85-0.93, rs = 0.85-0.90) than at the other speeds (0 and 60 degrees /sec) (r = 0.71 -0.90, rs = 0.70-0.85) obviously since the total work was registered at that speed. Both the peak torque and total work parameters of quadriceps as well as hamstrings correlated significantly with the subjective and functional outcome of the ACL insufficient knees (r = 0.75-0.84, rs = 0.76-0.85): the better the muscular function the better the outcome. In conclusion, in anteriorly unstable knees the total work analysis offers little additional information to that attained by the peak torque measurements. J Orthop Sports Phys Ther 1988;10(3):97-101.