Study on the Differential Effects of Blood Flow Restriction Training on Strength Gains and Precise Force Control

Research Background

Blood Flow Restriction (BFR) training, an emerging method for enhancing muscle strength, has garnered attention from researchers and clinical medicine in recent years. BFR training with low-load resistance exercise enhances muscle strength and endurance by restricting arterial blood flow and venous return near the limbs. Compared to traditional resistance training, BFR training enhances mechanical tension through cellular swelling and metabolic stress (including the production of lactate and reactive oxygen species), which facilitates muscle hypertrophy and promotes protein synthesis. However, the specific characteristics of BFR training using high-load versus low-load protocols are not yet clear. This study aims to explore the behavioral and neurophysiological mechanisms of BFR training with different loads and provide explanations for the differential effects on strength gains and precise force control.

Research Information

This study was conducted by Yen-Ting Lin, Chun-Man Wong, Yi-Ching Chen, Yueh Chen, and Ing-Shiou Hwang, and the results were published in the 2024 Journal of Neuroengineering and Rehabilitation. The article DOI link is: https://doi.org/10.1186/s12984-024-01419-5.

Research Methods

The study recruited 28 healthy adults, randomly assigned to high-load blood flow restriction (BFR-HL, n = 14) and low-load blood flow restriction (BFR-LL, n = 14) groups. Both groups underwent a 3-week BFR training program targeting static wrist extension, with training intensities of 25% and 75% of maximal voluntary contraction (MVC) respectively, and matched training volume. Pre- and post-training MVC and trapezoidal force tracking tests were conducted, and multi-channel surface electromyography (EMG) was used to obtain EMG signals from the extensor digitorum muscle.

Research Results

The BFR-HL group showed superior strength gains post-training compared to the BFR-LL group (BFR-HL: increase of 26.96 ± 16.33%; BFR-LL: increase of 11.16 ± 15.34%). However, only the BFR-LL group showed improvement in precise force control, with normalized force fluctuation changes being smaller than in the BFR-HL group. Data analysis revealed significant differences between the two groups in motor unit (MU) recruitment thresholds, discharge intervals, and their variability post-training, with the BFR-LL group tending to activate MUs with lower recruitment thresholds and higher discharge rates. Both groups consistently reduced MU discharge variability and common drive index (CDI).

Research Conclusion

This study provides new insights into BFR training. With matched training volume, BFR-HL training can lead to greater strength gains, while BFR-LL training shows better improvement in precise force control. The results highlight the unique effects of the two training protocols on force control and their potential mechanisms: adaptive changes in motor unit activation strategies induced by different training loads.

Research Highlights

The focus of this study is on comprehensively exploring the differential effects of BFR training under high-load and low-load conditions on force control and muscle activation, particularly in improving precise control. This has practical implications for the choice of rehabilitation and specialized strength training strategies. The uniqueness of the study lies in directly comparing high-load and low-load BFR training under volume-matched conditions, and incorporating neurophysiological parameters for in-depth analysis, providing a reliable foundation for future research on this training method.