Vastus medialis activation during knee extension exercises: evidence for exercise prescription.

CONTEXT Knee extension exercise is an important part of knee rehabilitation. Clinicians prescribe non-weight bearing exercise initially and progress patients to weight bearing exercise once they can perform a straight leg raise (SLR). OBJECTIVE Compare VM activation during a SLR and weight bearing exercises. DESIGN One-way repeated measures design. SETTING University Laboratory. SUBJECTS Fifteen healthy subjects. INTERVENTION One SLR exercise and 6 weight-bearing knee extension exercises. MAIN OUTCOME MEASURES Electromyographic amplitudes for the VM expressed as a percent maximum voluntary isometric contraction. RESULTS The SLR had greater activation than the single leg stance and bilateral squat exercises. The step-up and unilateral leg press exercises had the greatest activation. CONCLUSIONS SLR performance can be an important indicator for exercise progression. These results provide foundational knowledge to assist clinicians with exercise prescription.