This weeks #TrainingTips post is all about blood flow restricted training.
Ok let me explain, blood flow restricted training or BFR is a training method that can be used to improve performance through the restriction of blood flow the a working muscle. This is usually achieved by the application of a cuff to the limb which reduces arterial inflow and venous return. The restriction increases the working muscles oxygen demand and increases motor unit recruitment, which accelerates the time it takes to reach fatigue. This forces the muscles to work harder to generate contractions with the use of very light weights.
How does it work?
When you start performing muscle contractions on a limb that has a blood flow restriction the muscle fibres fatigue faster. This fatigue is caused by the build up of byproducts such as lactate, hydrogen ions and inorganic phosphate, due to the breakdown of creatine phosphate from the increased motor unit recruitment and decreased fibre contraction velocity, which increases the mechanical loading on active muscle fibres. That’s a mouth full I know and sounds extremely complicated and to a point it is, but put simply your causing your muscles to run out of fuel.
One of the great advantages of BFR is that you only train with light weights, 20-30% of 1RM is a great guide to go by. Not only that but BFR training has been shown to produce similar levels of hypertrophy and high threshold motor unit recruitment that comes from heavy mechanical loading on muscle fibres (when exerted effort is high). For this reason BFR can be a great tool for injury rehabilitation, where we can mitigate muscle loss caused by detraining, by still stimulating the muscle fibres despite the very light loads.
Now please don’t go out tying up all your limbs, this sort of training needs to be done correctly. The general advice is to wear specifically designed cuffs and to work with a tightness of an estimated 7 out of 10. However research shows that this perceived level of tightness will vary for everyone, for this reason in order to reduce the fluctuations in day-to-day pressure for BFR it is advised to use either automatic devices or if you’re using manual cuffs to start with a looser tightness until you become accustomed to the training method.
Is it dangerous?
If used incorrectly or over used then yes just like anything you need to train smart. There is also quite a lot of worry around this training method and the cause of blood clots, however evidence suggests that the restricted training increases the fibrinolytic potential therefore the release of anti-clotting agents. This means that using BFR can actually reduce the likelihood of blood clot formation contrary to most peoples belief. In fact during the period following a BFR exercise bout the rush of blood goes back to the arteries and endothelial cells, which activates the tissue plasminogen antigens responsible for the breakdown of clots.
All that being said anyone that does have hypertension, or suffers from haemophilia or an thrombotic/pulmonary embolism or DVT should avoid this training method
Have a great weekend guys.
Stay strong and live, love and laugh!