Elbow joint fatigue and bench-press training

• Published in: Journal of athletic training Vol. 49; no. 3; pp. 317 - 321
• Main Authors: Huang, Yen-Po, Chou, You-Li, Chen, Feng-Chun, Wang, Rong-Tyai, Huang, Ming-Jer, Chou, Paul Pei-Hsi
• Format: Journal Article
• Language: English
• Published: United States National Athletic Trainers Association 01.05.2014
• Subjects: Adult; Athletic Performance - physiology; Biomechanical Phenomena; Bodybuilding; Elbow; Elbow - physiology; Exercise - physiology; Humans; Injuries; Kinematics; Kinetics; Male; Models, Biological; Motion; Muscle Fatigue - physiology; Muscle Strength - physiology; Muscle, Skeletal - physiology; Muscular Strength; Original Research; Outcome Measures; Physical Fitness; Reference Values; Repetition; Sports training; Studies; Upper Extremity - physiology; Weightlifting; Young Adult; muscle strength; kinetics; myodynamic decline rate
• ISSN: 1062-6050; 1938-162X
• DOI: 10.4085/1062-6050-49.1.05

Bench-press exercises are among the most common form of training exercise for the upper extremity because they yield a notable improvement in both muscle strength and muscle endurance. The literature contains various investigations into the effects of different bench-press positions on the degree of muscle activation. However, the effects of fatigue on the muscular performance and kinetics of the elbow joint are not understood fully. To investigate the effects of fatigue on the kinetics and myodynamic performance of the elbow joint in bench-press training. Controlled laboratory study. Motion research laboratory. A total of 18 physically healthy male students (age = 19.6 ± 0.8 years, height = 168.7 ± 5.5 cm, mass = 69.6 ± 8.6 kg) participated in the investigation. All participants were right-hand dominant, and none had a history of upper extremity injuries or disorders. Participants performed bench-press training until fatigued. Maximal possible number of repetitions, cycle time, myodynamic decline rate, elbow-joint force, and elbow-joint moment. We observed a difference in cycle time in the initial (2.1 ± 0.42 seconds) and fatigue (2.58 ± 0.46 seconds) stages of the bench-press exercise (P = .04). As the participants fatigued, we observed an increase in the medial-lateral force (P = .03) and internal-external moment (P ≤ .04) acting on the elbow joint. Moreover, a reduction in the elbow muscle strength was observed in the elbow extension-flexion (P ≤ .003) and forearm supination-pronation (P ≤ .001) conditions. The results suggest that performing bench-press exercises to the point of fatigue increases elbow-joint loading and may further increase the risk of injury. Therefore, when clinicians design bench-press exercise regimens for general athletic training, muscle strengthening, or physical rehabilitation, they should control carefully the maximal number of repetitions.