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.