Fiber-Type-Specific Hypertrophy with the Use of Low-Load Blood Flow Restriction Resistance Training: A Systematic Review

• Published in: Journal of functional morphology and kinesiology Vol. 8; no. 2; p. 51
• Main Authors: Schoenfeld, Brad J, Ogborn, Dan, Piñero, Alec, Burke, Ryan, Coleman, Max, Rolnick, Nicholas
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 27.04.2023; MDPI
• Subjects: Blood flow; Bodybuilders; cross-sectional area; Exercise; fiber type; Hemodynamics; Hypertrophy; Ischemia; katsu; muscle growth; Muscle strength; occlusion; Review; Standard deviation; Strength training; Training; Weight training; cross-sectional area; fiber type; katsu; occlusion; muscle growth
• ISSN: 2411-5142; 2411-5142
• DOI: 10.3390/jfmk8020051

Emerging evidence indicates that the use of low-load resistance training in combination with blood flow restriction (LL-BFR) can be an effective method to elicit increases in muscle size, with most research showing similar whole muscle development of the extremities compared to high-load (HL) training. It is conceivable that properties unique to LL-BFR such as greater ischemia, reperfusion, and metabolite accumulation may enhance the stress on type I fibers during training compared to the use of LLs without occlusion. Accordingly, the purpose of this paper was to systematically review the relevant literature on the fiber-type-specific response to LL-BFR and provide insights into future directions for research. A total of 11 studies met inclusion criteria. Results of the review suggest that the magnitude of type I fiber hypertrophy is at least as great, and sometimes greater, than type II hypertrophy when performing LL-BFR. This finding is in contrast to HL training, where the magnitude of type II fiber hypertrophy tends to be substantially greater than that of type I myofibers. However, limited data directly compare training with LL-BFR to nonoccluded LL or HL conditions, thus precluding the ability to draw strong inferences as to whether the absolute magnitude of type I hypertrophy is indeed greater in LL-BFR vs. traditional HL training. Moreover, it remains unclear as to whether combining LL-BFR with traditional HL training may enhance whole muscle hypertrophy via greater increases in type I myofiber cross-sectional area.