Mixed
Low-intensity concentric resistance training combined with blood flow restriction (BFR) produces significant muscle hypertrophy and strength gains, whereas the same protocol using eccentric contractions fails to produce significant hypertrophy or strength gains.
If you use Blood Flow Restriction (BFR) training, you must perform the concentric (lifting) phase of the movement. Using the eccentric (lowering) phase with BFR at low loads will not build muscle or strength. Stick to concentric-focused movements with BFR to get the hypertrophy benefits.
These results suggest that CON-BFR training leads to pronounced acute changes in muscle size... Increases in muscle CSA and volume were lower in ECC-BFR... and only muscle CSA at 10-cm position increased significantly... Maximal voluntary isometric strength of elbow flexors was increased (p,0.05) in CON-BFR (8.6%), but not in ECC (3.8%).
Why this rating
Randomized controlled trial with within-subject design (contralateral arms), MRI-verified outcomes, and statistical significance, though sample size is small (n=10).
Source
Effects of Blood Flow Restricted Low-Intensity Concentric or Eccentric Training on Muscle Size and Strength
Tomohiro Yasuda et al. · PLoS ONE · 2012
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