Assessment of selected reports on the strength relationship of the knee musculature*

Fifty reports (1 956- 1981) pertaining to the measurement of knee flexor and extensor muscle strength were reviewed. The purpose of the literature review was to identify and evaluate the major variables which prevent a direct comparison of results obtained using isometric, isotonic, and isokinetic testing devices. Biomechanical factors were discussed relative to each type of device and included the length-tension relationships, angle of pull, and speed of contraction. Differences in the procedures used to acquire strength data were also reviewed. The conclusion was that the strength relationship between the knee flexor and extensor muscle groups was not adequately described by one or even a small range of strength values, and that there was no fixed strength relationship between these muscle groups that could be appropriate for every person and under all circumstances. This view was contrary to the generally accepted guideline for sports participants that the knee flexor muscle group should generate at least 60% of the force produced by the ipsilateral knee extensor muscle group.J Orthop Sports Phys Ther 1982;4(2):78.85.