Eighteen fresh frozen human Achilles tendons were used to test the ultimate strength of repaired tendon "ruptures." Three methods, the Kessler, the Bunnell, and the locking loop, were used to test the initial strength of Achilles tendon repair. The Kessler and Bunnell methods are current standard clinical configurations described for Achilles tendon repair. Under uniform and standardized laboratory conditions, the specimens were loaded to failure. The locking loop suture method was substantially stronger than either of the other two standard configurations. The latter two did not differ significantly from each other. The results of this study may be clinically relevant in terms of the choice of the repair method for surgically treated Achilles tendon ruptures.