Effect of stretching on ankle and knee angles and gastrocnemius activity during the stance phase of gait.

CONTEXT Stretching exercises are commonly prescribed for patients and healthy individuals with limited extensibility of the gastrocnemius muscle. OBJECTIVE To determine effects of gastrocnemius stretching on ankle dorsiflexion, knee extension, and gastrocnemius muscle activity during gait. DESIGN Randomized-control trial. SETTING Biomechanical laboratory. PARTICIPANTS Sixteen volunteers (9 men and 7 women, mean age = 27 y) with less than 5 degrees of passive ankle-dorsiflexion range of motion randomly assigned to an experimental or control group. INTERVENTION The experimental group performed gastrocnemius stretching for 3 wk. MAIN OUTCOME MEASURES Maximum ankle dorsiflexion, maximum knee extension, and EMG amplitude of the gastrocnemius muscles were measured between heel strike and heel-off before and after intervention. RESULTS No significant effect of group or time was found on maximum ankle dorsiflexion, maximum knee extension, or EMG activity of the medial or lateral gastrocnemius muscles between heel strike and heel-off. The experimental group had significantly greater passive ankle-dorsiflexion range of motion bilaterally at posttest than the control group. CONCLUSIONS Stretching did not alter joint angles or gastrocnemius muscle activity in the early to midstance phase of gait.