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.