Arch Hellen Med, 34(3), May-June 2017, 363-372
The relationship between isokinetic strength
I. Poulis,1 K. Vassis,1 E. Kapreli,1 T. Chados,2 S. Chados,3 A. Kanellopoulos1
OBJECTIVE To measure the correlation between isokinetic peak knee strength and functional performance 12 months after unilateral total knee arthroplasty (TKA).
METHOD The study participants, 15 patients who had undergone primary unilateral TKA, were tested at least 12 months postoperatively. Isokinetic quadriceps and hamstrings torque were assessed in the operated and non-operated legs using an electromechanical dynamometer at the angular velocities of 60°/s and 180°/s. Functional performance was assessed using the stair-climbing test (SCT), the Timed "Up-and-Go" test (TUG), and the 6-minute walk test (6MWT).
RESULTS Peak strength across two isokinetic velocities of the muscles of the knee was found to be correlated with the functional performance measurements. Functional performance on all three tests was significantly associated with the peak strength of the extensor muscles across both the isokinetic velocities. The 6MWT was significantly associated with peak torque of the flexor muscles across both isokinetic velocities. The only significant difference between the mean peak torque of the two knees was for the extensors at a velocity of 180°/sec. At this velocity, the mean peak torque of the extensor muscles of the operated leg was significantly weaker than that of the muscles in the non-operated leg. No difference was found between the flexor muscles of the operated and the non-operated leg at either 60°/sec and 180°/sec.
CONCLUSIONS Measurement of knee extensor strength may be a useful tool for clinicians in assessing and setting milestones during rehabilitation after TKA.
Key words: Exercise, Impairment, Pain, Spinal cord injury, Sport.