Stiff-leg extensions or dead lifts, whether with barbell or dumbbells, do create soreness in the leg biceps, but this soreness is due to overstretching the tissue and creating tears. As much of the stress is assumed by the lower back and the hips, it is best to avoid this movement.

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For toning and shaping purposes, stick to leg curls. The seated position allows the use of the most weight, but the "mind-muscle" link is not as strong as the standing option, which allows each leg to be worked independently and with greater control over each contraction.

Lying curls may unnecessarily stress the lower back, and at times provide a discomfort to the area of the solar plexus. Because the leg biceps is incorporated in press movements, the isolation provided by three or four sets of 10 to 20 well-controlled reps is sufficient.