Delayed-onset muscle soreness induced by low-load blood flow-restricted exercise

Area of Science:

• Exercise Physiology
• Sports Science
• Muscle Physiology

Background:

• Delayed-onset muscle soreness (DOMS) is a common response to strenuous exercise.
• Blood flow restriction (BFR) exercise is increasingly used for training and rehabilitation.
• The specific contribution of concentric versus eccentric actions to DOMS in BFR exercise is not fully understood.

Purpose of the Study:

• To quantify the magnitude of DOMS following knee extension BFR exercise.
• To compare DOMS induced by BFR exercise versus non-BFR exercise.
• To determine the differential contribution of concentric (CON) and eccentric (ECC) actions during BFR exercise to DOMS.

Main Methods:

• Experiment 1: Participants performed unilateral knee extensions with and without BFR at 35% maximal voluntary contraction (MVC) to failure.
• Experiment 2: Participants performed unilateral knee extensions with BFR, focusing solely on concentric or eccentric actions.
• Measurements included resting soreness, pain-pressure threshold (PPT), MVC, and vastus lateralis cross-sectional area (CSA) at various time points post-exercise.

Main Results:

• BFR exercise induced significantly greater DOMS, reduced PPT, and decreased MVC compared to non-BFR exercise at 24 hours post-exercise.
• Concentric BFR exercise resulted in higher resting soreness and greater MVC reduction than eccentric BFR exercise at 24 hours.
• BFR exercise at 35% MVC with low-tension concentric contractions elicited muscle damage and mild DOMS.

Conclusions:

• Knee extension BFR exercise can induce mild DOMS and muscle damage.
• Concentric actions during BFR exercise contribute more significantly to DOMS than eccentric actions.
• BFR exercise can elicit muscle damage even under conditions involving low-tension concentric contractions.