A new running-locking loop suture technique has been developed to increase tendon repair strength and to provide better tendon edge inversion. Biomechanical analysis documented the failure mechanism and the failure strength of various circumferential repair techniques. When compared with two well-known techniques, the simple circumferential running suture and Lembert running suture, the locking suture technique was shown to have 3.77 and 1.68 times greater tensile failure strength and 1.73 and 1.26 times greater stiffness than these traditional suture methods. A running peripheral locking suture may help augment the strength of tendon repair.