Elbow load during different types of bench-press exercise

The bench press is one of the most popular weight training open-kinetic chain exercise (OKCE) for the upper extremity. Reviewing the literature, there is a very little research regarding the biomechanical analysis of the OKCE of the upper extremity. The purpose of this study is to develop an OKCE testing model of the upper extremity by using the 3D Motion Analysis System. Furthermore, elbow joint loading of two different hand grip position during the bench-press exercise will be investigated. Thirteen male students volunteered for the study. Their average age was 26.1 years, with an average height of 170.6 cm, and an average weight of 70.3 kg. With both hands in neutral position, each subject was asked to perform bench-press type 1 (normal shoulder width), and bench-press type 2 (150% shoulder width). During the type 2 bench-press exercise, there is a significant increase in anterior-posterior and medial-lateral force on the elbow joint loading than the type 1 bench-press exercise. The valgus-varus, flexion-extension moment, and supination-pronation moment of the type 2 bench-press exercise are also greater than the type 1 bench-press exercise. As shown in this study, keeping the distance of both hand grips as shoulder width may reduce the elbow joint loading during bench-press exercise. These data will provide helpful information in clinical rehabilitation and treatment of the upper-extremity injures.