Context:
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.
Objective:
To investigate the effects of fatigue on the kinetics and myodynamic performance of the elbow joint in bench-press training.
Design:
Controlled laboratory study.
Setting:
Motion research laboratory.
Patients or Other Participants:
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.
Intervention(s):
Participants performed bench-press training until fatigued.
Main Outcome Measure(s):
Maximal possible number of repetitions, cycle time, myodynamic decline rate, elbow-joint force, and elbow-joint moment.
Results:
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.
Conclusions:
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.