Intraoperative measurement of human gracilis muscle isometric forces as a function of knee angle

In this study, it is aimed at measuring for the first time the isometric force of human gracilis (G) muscle as a function of joint angle, intraoperatively. Experiments were conducted during anterior cruciate ligament reconstruction surgery. The knee angle was fixed at 120°, 90°, 60°, 30° and 0° respectively and active isometric forces of this muscle were measured using a buckle force transducer. Limited correlation was found between the anthropometric data of the subjects and the maximal G muscle force. Accordingly, we suggest that in interventions targeting G muscle, a patient specific approach needs to be planned for achieving optimal results. G muscle was shown to be functional for almost all of the knee angle range studied. This result indicates that G muscle contributes to the knee moment for even very low muscle lengths during major daily activities including walking and sit-to-stand motion.