Effect of fatigue of bench-press training on shoulder joint

Paul Pei Hsi Chou, Yen Po Huang, Feng Chun Chen, Rong-Tyai Wang, You Li Chou

Research output: Contribution to journalArticlepeer-review


Bench-press exercises are convenient, easily learned, and readily adapted to various levels of difficulty. This study investigates the effect of the fatigue on the maximum possible number of repetitions, the cycle time, myodynamic decline rate and joint force and joint moment in bench-press exercises. The myodynamic decline rate in different isometric test conditions is measured using an isokinetic dynamometer and the kinetics at the maximum possible number of repetitions is measured. The aim of the experiments was to analyze the effect of fatigue on the shoulder joint in the Initial Stage (IS) of the repetitive bench-press exercise and in the Fatigue Stage (FS). Fifteen physically healthy male students performed bench-press exercises until the fatigue stage occurred. The joint kinematics and kinetics in the initial stage and fatigue stage of the bench-press exercise were calculated and analyzed using a laboratory-developed three-dimensional motion analysis system. Decline Rate of Bench-Press (MDRBP) were examined by measuring the torque at the shoulder using an isokinetic dynamometer. The results showed that the fatigue contribute to a significant effect on the myodynamic and kinetic performance of the shoulder joint. After Bench-Press (FSABP), there was significant difference between the cycle time in the IS and FS. When subjects approach fatigue condition, the axial compression forces decreased and the abduction/adduction moment increased. Significant decrease in muscle strength were also observed in shoulder abduction/adduction, flexion/extension, and internal rotation/external rotation. The results obtained in this study not only describe the relationship between the effect of fatigue across the shoulder joint myodynamics and kinetics but also provide useful biomechanical information for exercise training and clinical rehabilitation regarding to the strategy of performing bench-press exercise. In conclusion, performing bench-press until completely fatigue for strengthening the upper extremity may be a risk of injury. Therefore, bench-press repetition should be carefully monitored before the stage of fatigue in athletic training or muscle strengthening of the upper extremity.

Original languageEnglish
Pages (from-to)515-521
Number of pages7
JournalJournal of the Chinese Society of Mechanical Engineers, Transactions of the Chinese Institute of Engineers, Series C/Chung-Kuo Chi Hsueh Kung Ch'eng Hsuebo Pao
Issue number6
Publication statusPublished - 2011 Dec 1

All Science Journal Classification (ASJC) codes

  • Mechanical Engineering


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