More equals better in BFR Training?
July 21, 2022
📄A Meta-Analysis have recently explored the effect of relative pressure and relative load on strength gains.
Introduction:
Important parameters for BFR are % of Limb Occlusion Pressure (LOP) and % of 1RM.
Background:
Individualizing pressure (% of LOP) produces uniform physical-stress VS fixed pressures.
High-Load Resistance Training (HLRT) seems superior for strength VS Moderate/Low-Load resistance training.
🔎Aims:
Determine a minimal and optimal %LOP for BFR + minimum % of 1RM, volume load, and total reps required for significant strength gains.
Method:
PRISMA guidelines. 775 identified articles, 21 included in the meta-analysis.
📊Results:
BFR at 1RM ≤20% or ≥80% inferior VS no-BFR HLRT.
≤50% and ≥ 80% of LOP did not produce significant strength gains VS controls.
BFR at ≥30 %1RM matching no-BFR HLRT (70–80% 1RM).
40–60% 1RM BFR may produce results exceeding no-BFR HLRT!?
⚠️Limitations:
Hypertrophy may be achieved at different %LOP and/or %1RM.
💡Conclusion:
% of 1RM appears to be more important VS % of LOP.
50–80% LOP seems to be the sweet spot.
💬Discussion:
Future studies should compare gender, age, and training experience discrepancies.
Thus, mentioned in the Introduction, no analysis of the optimal volume load, and/or total repetitions were included!?
Also worth noting is the lack of analysis and/or comparison as the proposed Pressure-Load Continuum!?
Looking at previous meta-analysis when utilizing 30% of 1RM, there is no additional effect at ≥50% LOP!?
Mechanistically, it seems using loads >40% 1RM intramuscular occlusion occurs naturally for most muscle groups relative to inter-individual variance in muscle size..
Page 5 – “Interestingly 40% 1RM with BFR produces significantly greater strength improvements when moderate pressure was applied (70% LOP), but significantly lower strength improvements at low-moderate pressure (40% LOP).”
This statement seems rather bold as only 2 of the included original papers explored 40% of 1RM and the high pressure study combined No-HLRT + BFR training sessions..
Primary Source:
Das & Paton (2022) Is There a Minimum Effective Dose for Vascular Occlusion During Blood Flow Restriction Training?
Secondary source:
Queiros et al. (2021) Myoelectric Activity and Fatigue in Low-Load Resistance Exercise With Different Pressure of Blood Flow Restriction- A Systematic Review and Meta-Analysis
Loenekke et a. (2014) Blood flow restriction pressure recommendations: the hormesis hypothesis
Ilett et al. (2019) The Effects of Restriction Pressures on the Acute Responses to Blood Flow Restriction Exercise
Cerqueira et al. (2021) Repetition Failure Occurs Earlier During Low-Load Resistance Exercise With High But Not Low Blood Flow Restriction Pressures: A Systematic Review and Meta-analysis
Pignanelli et al. (2019) Low-load resistance training to task failure with and without blood flow restriction- Muscular functional and structural adaptations
Loenneke et al. (2015) Effects of exercise with and without different degrees of blood flow restriction on torque and muscle activation
Dankel et al. (2017) Are Higher Blood Flow Restriction Pressures More Beneficial When Lower Loads Are Used
Counts et al. (2016) Influence of relative blood flow restriction pressure on muscle activation and muscle adaptation
