Effects of Blood Flow Restriction Training on Muscle Strength and Architecture

Effects of blood flow restriction training on physical fitness among athletes: a systematic review and meta-analysis

Blood flow restriction training (BFRT) is an effective, scientific and safe training method, but its effect on the overall quality of athletes remains unclear. The aim of this systematic review with meta-analysis was to clarify the effects of BFRT on the physical fitness among athletes. Based on the PRISMA guidelines, searches were performed in PubMed, Web of Science, SPORTDiscus, and SCOUPS, the Cochrane bias risk assessment tool was used to assess methodological quality, and RevMan 5.4 and STATA 15.0 software were used to analyze the data. A meta-analysis of 28 studies with a total sample size of 542 athletes aged 14-26 years and assessed as low risk for quality was performed. Our results revealed that the BFRT intervention had small to large improvements in the athletes' strength (ES = 0.74-1.03), power (ES = 0.46), speed (ES = 0.54), endurance (ES = 1.39-1.40), body composition (ES = 0.28-1.23), while there was no significant effect on body mass (p > 0.05). Subgroup analyses revealed that moderator variables (training duration, frequency, load, cuff pressure, and pressurization time) also had varying degrees of effect on athletes' physical fitness parameters. In conclusion, BFRT had a positive effect on the physical fitness parameters of the athletes, with significantly improved strength, power, speed, endurance and body composition, but not body mass parameters. When the training frequency ≥ 3 times/week, cuff pressure ≥ 160 mmHg, and pressurization time ≥ 10 min, the BFRT group was more favorable for the improvement of physical fitness parameters.

Potential Moderators of the Effects of Blood Flow Restriction Training on Muscle Strength and Hypertrophy: A Meta-analysis Based on a Comparison with High-Load Resistance Training

BACKGROUND

While it has been examined whether there are similar magnitudes of muscle strength and hypertrophy adaptations between low-load resistance training combined with blood-flow restriction training (BFR-RT) and high-load resistance training (HL-RT), some important potential moderators (e.g., age, sex, upper and lower limbs, frequency and duration etc.) have yet to be analyzed further. Furthermore, training status, specificity of muscle strength tests (dynamic versus isometric or isokinetic) and specificity of muscle mass assessments (locations of muscle hypertrophy assessments) seem to exhibit different effects on the results of the analysis. The role of these influencing factors, therefore, remains to be elucidated.

OBJECTIVES

The aim of this meta-analysis was to compare the effects of BFR- versus HL-RT on muscle adaptations, when considering the influence of population characteristics (training status, sex and age), protocol characteristics (upper or lower limbs, duration and frequency) and test specificity.

METHODS

Studies were identified through database searches based on the following inclusion criteria: (1) pre- and post-training assessment of muscular strength; (2) pre- and post-training assessment of muscular hypertrophy; (3) comparison of BFR-RT vs. HL-RT; (4) score ≥ 4 on PEDro scale; (5) means and standard deviations (or standard errors) are reported or allow estimation from graphs. In cases where the fifth criterion was not met, the data were requested directly from the authors.

RESULTS

The main finding of the present study was that training status was an important influencing factor in the effects of BFR-RT. The trained individuals may gain greater muscle strength and hypertrophy with BFR-RT as compared to HL-RT. However, the results showed that the untrained individuals experienced similar muscle mass gains and superior muscle strength gains in with HL-RT compared to BFR-RT.

CONCLUSION

Compared to HL-RT, training status is an important factor influencing the effects of the BFR-RT, in which trained can obtain greater muscle strength and hypertrophy gains in BFR-RT, while untrained individuals can obtain greater strength gains and similar hypertrophy in HL-RT.

Effects of Minimal-Equipment Resistance Training and Blood Flow Restriction on Military-Relevant Performance Outcomes

ABSTRACT

Cintineo, HP, Chandler, AJ, Mastrofini, GF, Lints, BS, McFadden, BA, and Arent, SM. Effects of minimal-equipment resistance training and blood flow restriction on military-relevant performance outcomes. J Strength Cond Res 38(1): 55-65, 2024-This study compared minimal-equipment resistance training (RT) with and without blood flow restriction (BFR) to traditional-equipment RT on performance and body composition changes over 6 weeks. Reserve officers' training corps cadets and midshipmen (N = 54, 40.7% female) were randomized into traditional-equipment RT (TRAD), minimal-equipment RT (MIN), or minimal-equipment RT with BFR (MIN + BFR). Performance and body composition were assessed pretraining and post-training, and measures of intensity and workload were evaluated throughout. Performance assessments included the army combat fitness test (ACFT), countermovement vertical jump, 3RM bench press, and V̇O2max; body composition measures included body fat percentage, fat-free mass, and muscle and tendon thickness. All groups trained 4 days per week after a full-body routine. Data were analyzed by mixed-effects models (α = 0.05). Group-by-time interactions for 3RM deadlift and 3RM bench press (p < 0.004) showed larger improvements for TRAD compared with MIN and MIN + BFR. Time main effects for all other performance variables, body fat percentage, fat-free mass, and muscle thickness (p ≤ 0.035) indicated improvements in all groups. A group-by-time interaction for blood lactate (p < 0.001) and group main effects for heart rate (p < 0.001) and workload variables (p < 0.008) indicated higher intensity and workload for MIN and MIN + BFR compared with TRAD. A sex-by-time interaction for 3RM deadlift (p = 0.008) and sex-by-group-by-time interaction for 3RM bench press (p = 0.018) were also found. Minimal-equipment RT improved performance and body composition, although strength improvements were greater with traditional equipment. Minimal-equipment RT and minimal-equipment RT with BFR exhibited higher exertion levels than TRAD, although adaptations were similar. Overall, individuals can improve performance and body composition using portable, field-expedient RT equipment.

Low-load strength resistance training with blood flow restriction compared with high-load strength resistance training on performance of professional soccer players: a randomized controlled trial

BACKGROUND

The aim of this study is to evaluate the effectiveness of low-load blood flow restriction strength resistance training (LL-BFR) compared to high load strength resistance training (HL) on performance of professional soccer players.

METHODS

Eighteen male players from National Soccer Professional League were randomly allocated into two groups: LL-BFR, who performed a 6-weeks strength training program with low load (20-35% of one-repetition maximum-[1RM]), or HL, who performed a 6-week resistance training program with high load (70-85% 1RM). Before and after, thigh girth, vertical jump, lower limb strength, vertical force-velocity profile (F-v), and 30-m sprint were evaluated.

RESULTS

After the training program, both LL-BFR and HL induced significant increases compared to baseline in thigh girth (+3.3% for LL-BFR and +3.1% for HL) and maximal velocity during sprinting (+6.0 and +6.2%, respectively), without between-group differences. In reference to FV, only HL players improved imbalance (-54.4%), maximal theoretical force production (+10.4%) and decreased extension velocity (-20.5%) compared to baseline, without between-group differences. Only LL-BFR induced increases in maximum voluntary contraction of left hamstring compared to baseline (+13.8%), without between-group differences. No differences were shown for the rest of variables (P>0.05).

CONCLUSIONS

Although LL-BFR may increase muscle circumference and sprint ability, these results are similar to those induced with HL in male professional soccer. In terms of F-v, only HL induced improvements, but these changes were not greater than those observed after LL-BFR.

Endogenous and Exogenous Antioxidants in Skeletal Muscle Fatigue Development during Exercise

Muscle fatigue is defined as a decrease in maximal force or power generated in response to contractile activity, and it is a risk factor for the development of musculoskeletal injuries. One of the many stressors imposed on skeletal muscle through exercise is the increased production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), which intensifies as a function of exercise intensity and duration. Exposure to ROS/RNS can affect Na⁺/K⁺-ATPase activity, intramyofibrillar calcium turnover and sensitivity, and actin-myosin kinetics to reduce muscle force production. On the other hand, low ROS/RNS concentrations can likely upregulate an array of cellular adaptative responses related to mitochondrial biogenesis, glucose transport and muscle hypertrophy. Consequently, growing evidence suggests that exogenous antioxidant supplementation might hamper exercise-engendering upregulation in the signaling pathways of mitogen-activated protein kinases (MAPKs), peroxisome-proliferator activated co-activator 1α (PGC-1α), or mammalian target of rapamycin (mTOR). Ultimately, both high (exercise-induced) and low (antioxidant intervention) ROS concentrations can trigger beneficial responses as long as they do not override the threshold range for redox balance. The mechanisms underlying the two faces of ROS/RNS in exercise, as well as the role of antioxidants in muscle fatigue, are presented in detail in this review.

Effects of blood flow restriction training on anthropometric and blood lipids in overweight/obese adults: Meta-analysis

Abstract: Purpose: To systematically evaluate the effects of blood flow restriction training (BFRT) on anthropometric indicators and blood lipids in overweight/obese adults.

Methods: A literature search was conducted on PubMed, Web of Science, Embase, Scopus, SPORTDiscus and Cochrane Library databases to determine the final literature based on inclusion and exclusion criteria. Review Manager 5.4.1 was used to evaluate the quality of the literature based on the Cochrane bias risk assessment tool, and Stata 17.0 software was used for Meta-analysis.

Results: A total of 3,985 articles were screened, and five of the studies were included in the Meta-analysis, with a total 66 participants. In each study, subjects were measured before and after BFRT. Meta-results showed that BFRT significantly reduced BMI, lowered body weight, body fat % and waist circumference, significantly reduced total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) level, lowered triglycerides, and increased high-density lipoprotein cholesterol (HDL-C) level in overweight/obese adults.

Conclusion: BFRT can be used as a safe and effective exercise prescription for personalized weight/fat loss. BFRT significantly reduces BMI by reducing body weight, body fat %, and waist circumference and has the effect of improving body composition. It also significantly reduced TC and LDL-C and tends to decrease TG and increase HDL-C in overweight/obese adults, potentially reducing the incidence of cardiovascular disease.