Distal biceps reconstruction for chronic rupture often requires a graft to recover length and allow for distal tendon reattachment to bone. Our purpose was to assess peak strength and endurance recovery following biceps reconstruction with tendon grafts. We hypothesized that allograft reconstruction would result in decreased flexion and supination peak strength and endurance. Consecutive distal biceps reconstructions with allograft, performed for chronic ruptures between January2008 and March2018 at a single institution, were reviewed. Isokinetic dynamometry for peak strength and endurance testing was performed on the operative and contralateral arms in flexion and supination. Functional outcomes and overall satisfaction with the operation were determined. Eleven patients were available for a complete evaluation, including dynamometry, at a mean of 46 months postoperatively. Reconstructions demonstrated a nonsignificant trend toward decreased peak flexion strength (P = .06), and significantly decreased peak supination strength (P = .01) compared with the unaffected arm. There were no differences in flexion and supination endurance between the affected and unaffected arms. Using standardized outcome scales, patients reported excellent function. Chronic biceps ruptures undergoing reconstruction are highly functional and patients are satisfied. Somewhat surprisingly, supination and flexion endurance were equal to the contralateral, uninvolved arm. However, this procedure does not restore peak supination strength.