Biceps brachii elastography in well-trained men post eccentric exercise-induced muscle damage

Area of Science:

• Biomechanics
• Exercise Physiology
• Musculoskeletal Imaging

Background:

• Muscle stiffness can be non-invasively assessed using elastography techniques like supersonic shearwave elastography (SWE).
• Limited research exists on the acute effects of eccentric exercise-induced muscle damage (EIMD) in well-trained individuals.

Purpose of the Study:

• To investigate the immediate and short-term effects of eccentric training on biceps brachialis stiffness using supersonic shearwave imaging (SSI).
• To assess changes in muscle soreness and maximal voluntary isometric contraction (MVIC) following eccentric exercise in well-trained men.

Main Methods:

• Thirteen well-trained males underwent baseline measurements of elastography, elbow flexor MVIC, and muscle soreness.
• Participants performed an eccentric exercise protocol (4 sets x 10 repetitions).
• Measurements were repeated immediately post-exercise, at 10 minutes, 48 hours, and 96 hours.

Main Results:

• Significant reductions in biceps brachialis stiffness (shear modulus) were observed immediately and 10 minutes post-exercise.
• Maximal voluntary isometric contraction (MVIC) significantly decreased immediately post-exercise, at 10 minutes, and 48 hours.
• Muscle soreness peaked at 48 hours and persisted through 96 hours.

Conclusions:

• Immediate reductions in biceps brachialis stiffness and MVIC post-eccentric exercise suggest mechanical stress and potential sarcomere rupture in trained individuals.
• Trained individuals may respond differently to EIMD compared to untrained individuals.
• Elastography is applicable for monitoring acute biomechanical changes after high-intensity exercise.