Patients randomized to this group will receive a sciatic nerve block with the catheter tip insertion at the subgluteal location 1-3 cm caudad to the inferior border of the gluteus maximus muscle.

Patients randomized to this group will receive a sciatic nerve block with the catheter tip insertion at the popliteal location 1-3 cm cephalad to the sciatic bifurcation.

Patients randomized to this group will receive a sciatic nerve block with the catheter tip insertion at the subgluteal location 1-3 cm caudad to the inferior border of the gluteus maximus muscle. After catheter placement, outcome measures will be assessed.

We will evaluate hamstring strength which is innervated by the sciatic nerve with an isometric force electromechanical dynamometer to measure the force produced during a maximum voluntary isometric contraction (MVIC) in a seated position with the knees flexed at 90º

We will evaluate tolerance of transcutaneous electrical stimulation. Electrocardiogram pads will be placed on the plantar and dorsal aspects of the foot, and attached to a nerve stimulator. The current will be increased from 0 mA until subjects described a "buzzing" sensation (not painful), at which time the current will be recorded as the tolerated level and the nerve stimulator turned off.