PALMARIS LONGUS MUSCLE CONTRIBUTION TO MAXIMUM TORQUE AND STEADINESS IN HIGHLY SKILLED GRIP AND NON-GRIP SPORT POPULATIONS

Background: The anatomy, origin, function, and appearance of the Palmaris Longus Muscle (PLM) in different populations are well studied. However, little is known about its contribution to wrist flexion movements in sports. This study investigates whether the existence or absence of the PLM affects maximal torque output or torque consistency of submaximal wrist flexion moment. Methods: One hundred ninety-seven well-trained sports students were clinically examined to ascertain the presence of the PLM. Forty of them from different sport disciplines were assigned to two groups (athletes in handgrip sports: HG, athletes in non-handgrip sports: NHG). Their 80 upper limbs were divided based on the PLM-presence/absence and hand-dominance/non-dominance. Maximal Isometric Torque (MIT) at 150º, 180º, and 210º wrist angle, and torque steadiness at 150º and 180º, at 25%, 50%, and 75% of MIT were measured on a Humac Norm dynamometer. Results: In all MIT tests, HGs significantly surpassed NHGs, independently of the dominant or non-dominant side in presence of the PLM (p <.05). Steadiness was significantly higher in HGs than in NHGs in dominant hands having the PLM, at 25% and 75% of MIT at both angles (p <.05). Conclusions: It is concluded that the existence of the PLM provides an advantage in sustained handgrip sports (throwers, racquet sports, basketball, handball players), contributing positively to decreased torque variability and higher maximal torque independently of muscular length. Important implications for sports performance and injury prevention have also resulted