The Study
Delayed myonuclear addition, myofiber hypertrophy, and increases in strength with high-frequency low-load blood flow restricted training to volitional failure.
This study watched 13 people do a special kind of exercise and noticed their muscles got a little bigger and stronger after a while — but we don’t know if the exercise actually caused it, because there was no group that didn’t do the exercise to compare with.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
People did light weight lifting with their legs squeezed tight, and their muscles didn't get bigger right away — they got bigger later, even after they stopped training.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 552 / 100
Quality score
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — muscles and repair cells kept growing even after stopping, which is unusual and might mean the body needs time to recover fully.
- 2Satellite cells went up 70%–147%, muscle size went down 6%–15% then up 6%–19%, strength went up 6% after 20 days of rest.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of applied physiology
Year
2019
Authors
T. Bjørnsen, M. Wernbom, A. Løvstad, G. Paulsen, R. D’Souza, D. Cameron-Smith, Alexander Flesche, J. Hisdal, S. Berntsen, T. Raastad
Related Content
Claims (10)
When resistance training is performed to muscle failure, low-load with many repetitions produces the same amount of muscle fiber growth as high-load with few repetitions.
When people lift weights until they can no longer complete another repetition, muscle growth is the same whether they use light, moderate, or heavy weights.
In young adults, performing high-frequency, low-load resistance exercise with restricted blood flow results in a 70%–80% increase in satellite cell numbers in type I and II muscle fibers after the first training session, and a further increase to 80%–147% after the second session.
High-frequency, low-load resistance exercise with restricted blood flow causes a temporary 6%–15% reduction in the size of both slow-twitch and fast-twitch muscle fibers during the first training phase, followed by a 6%–19% increase in size after the second training phase.
High-frequency, low-load resistance exercise with blood flow restriction is associated with a delayed increase in Pax7 and p21 messenger RNA during training and delayed alterations in myostatin, IGF1R, MyoD, myogenin, and cyclinD1/D2 messenger RNA levels 3 to 10 days after exercise.
In untrained individuals, a specific type of resistance exercise using restricted blood flow and low weights, done to exhaustion over two short training blocks with a 10-day break, results in a 19% larger type I muscle fibers and an 11% larger type II muscle fibers, with the largest increases observed 10 days after the training ends.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.