So, some of you may have noticed the acronym BFR appearing on some sessions, especially in Strava, for several athletes that you may know, including myself.
Why mention this is because there’s been a number of questions that I have received from both athletes that I coach as well as weekend warriors who are keen to understand what BFR actually is. It seems that as soon as you post anything on Strava, the stalkers start wondering if there some special sauce that they are missing out on.
In this instance THERE IS some special sauce.
But let me make it clear from the outset that this is NOT for everyone and more importantly needs to be done in a very controlled manner to not elicit any injury.
So, what is BFR?
BFR stands for blood flow restriction (otherwise known as occlusion training). For those of you that frequent the more popular gyms, may have seen some weightlifters walking around with what seems to be a tourniquet around either their arms or their legs. This is kind of where BFR has its roots. A number years ago it was shown that by occluding the muscle by the use of a tourniquet (only occluding venous blood flow!) you could obtain close to the same benefits by lifting only 20% of the maximum weight. So instead of beating yourself to a pulp in the gym by lifting heavy weights, you can achieve up to 90% of the same gains by only lifting 20% of the normal weight that you would lift.
That obviously led the exercise physiologists to consider whether a similar response would be seen in endurance training. Again, let me point out that the application of BFR in endurance training is very very new. I’ve been following it and testing it out over the last 12 months, but it is an emerging field.
To date there are a number of studies showing benefits to the endurance athlete, but again very specific responses and in very specific conditions, which I’ll touch on a little later.
So firstly, an overview of some of the research (I’ve just picked out two over a good number of research papers):
What exactly is happening in the body that causes this response – time to geek out!
During occlusion training, the Type 1 and 2a fibres are starved of oxygen decreasing their work capacity. This increases a neural stimulation to other fibres of the same type that may be inactive and increases motor recruitment. That is to say when we actively contract the muscle, we only ever activate a percentage of its contained fibres. The percentage activated will vary from person to person but will never reach 100% of the muscle.
By activating more fibres through occlusion training, we are better able to train more of the muscle to the demands of our sport than we would likely be able to through standardised training alone. Once the Type 1 and 2a fibres are depleted and fatigued, we recruit Type 2b fibres to continue the exercise in the absence of oxygen.
This lack of oxygen creates a hypoxic environment within the tissue causing the release of Vascular Endothelial Growth Factor (VEGF). This signaling protein chemical is responsible for the creation of new blood vessels and their supporting networks. Blood vessels once complete will increase the surface area ratio of diffusion within the tissue allowing more oxygen and key nutrients to the tissue in the future along with increased lactate threshold.
With occlusion training reducing levels of oxygen available to working muscles, a lactic acid/lactate build-up occurs dramatically quicker than expected. This chemical soup build-up is counteracted by the body converting it back to pyruvate. But with training, the body is better able to hold off and endure this acidic state for longer periods of time.
While more applicable for those completing High-Intensity Endurance Exercise (HIEE), the applications of occlusion training are useful for a variety of sports.
So that sounds all great, let’s go and purchase occlusion cuffs and start starving the muscle of oxygen!
Well not exactly!
This is where it becomes a lot more complex on how and when we should be using BFR to elicit adaptations. Again, let me just state that BFR tends to give close to the same level of improvement as normal training. But that’s the catch it’s not as good but rather only gets close to normal levels (although we can manipulate some responses that we wouldn’t get out of training, but this is athlete specific)
Some of the applications we would use it would be
If we know that you suffer from a venous occlusion (thanks to Moxy testing) then yes BFR may be a way to increase plasma volume and elicit additional adaptation over and above your normal training.
I’m not going to get into the detail around the training protocol and how to apply BFR. Pressures and application are extremely important and to a point specific to the person and session, hence rather reach out to me if you want to know if this is for you,.