Warm-up effect on active and passive arthrometric assessment of knee laxity.

Abstract

To determine the influence of a warm-up protocol suitable for use in clinical settings on tibial displacement and muscle activity during arthrometric knee laxity assessment. Intervention study in which the subjects served as their own controls. The Biomechanics Research Laboratory, University of Wollongong, Wollongong, New South Wales, Australia. Ten volunteers who reported no history of knee trauma or disease. A warm-up consisting of 10 minutes of ergometer cycling (60rpm) followed by two sets of three hamstring muscle stretches. Outcome measures were: (1) anterior tibial translation and knee extension force assessed using a Dynamic Cruciate Tester for each subject's right knee during active and passive testing, and (2) intensity of quadriceps and hamstring muscle activity during knee laxity testing. There was significantly less quadriceps activity after warm-up (t = 2.419, p = .039). However, there was no significant difference between anterior tibial translation, knee extension force, or hamstring muscle activity results before and after warm-up in either active or passive tests. A warm-up suitable for use in a clinical setting is not required before arthrometric assessment of knee laxity.