‘Endurance athletes need to embrace BFR’: Adam Daniel explains why

There’s a type of training system out there that you may not have considered, especially for endurance training, called Blood Flow Restriction Training. This may sound counterintuitive since your muscles need blood flow to do what they do best, right?

Not always! After delving into the research and applying Blood Flow Restriction in my own and my clients’ training, it’s proved to be an incredibly effective training strategy and one that endurance athletes need to embrace to perform faster for longer.

How does it work?

Simply put, Blood Flow Restriction Training, or BFR for short, is a type of training in which you heavily reduce the load and intensity of the exercise, while simultaneously trapping blood in the working muscles to accelerate muscle fatigue.

Layering a bit more of the science into the explanation, BFR creates a hypoxic environment by removing oxygen from the muscle. This occurs because oxygen is used up for energy production by the muscles, and the subsequent deoxygenated blood trapped by the restriction leads to blood pooling and swelling in the muscle cells. This stressful environment is the precursor for all BFR protocols (Strength, Endurance, Recovery, and Preparation BFR), artificially stressing the muscles before performing your chosen protocol to enhance the desired outcome.

What does trapping blood do to the working muscle?

The research shows that trapping blood in the working muscle creates a metabolic overload that is usually seen in muscles performing higher-intensity work, such as lifting very heavy weights or running at a very fast pace (1).

What does this have to do with Endurance Training?

Although much of the literature that exists on BFR revolves around Resistance Training, there is still plenty of evidence to show that it has benefits for endurance athletes as well.

One 2018 study illustrated that applying BFR to an 8-week cycling protocol enhanced quad strength and hypertrophy, as well as VO2 max more significantly compared to the group who performed the cycling protocol without the BFR (2). What makes this very surprising is that this was achieved while producing less total volume than the non-BFR group.

Another study from 2010 (3) compared BFR cycling for 15 minutes at 40% VO2 max to another group that biked at 40% VO2 max for 45 minutes. Both groups performed the exercise routine three times per week for eight weeks.

The group that used BFR saw the following effects (not seen in the control group):

– Increased quad and thigh muscle volume

– Increased knee extension strength

– VO2 max increased by 6.4%

– Increased exercise time to exhaustion

BFR Training has the potential to be a brilliant strategy for the time-poor weekend warrior or amateur athlete.

What are the benefits for the time-poor athlete?

BFR is a great opportunity and tool for endurance athletes to improve their training efficiency. The current evidence shows that it’s important to combine Endurance Training with a Strength Training programme to maximise your performance. However, the challenge when integrating Strength Training into the “miles” is the requirement for additional overall training time. It potentially takes away from other obligations you may have in your life – which can be quite inconvenient.

With BFR, you’re able to simultaneously receive a Strength Training stimulus whilst also completing your regular Endurance Training activities. In both the above studies, an increase in strength was seen. Whilst maybe not as notable as that of a focused Resistance Training programme, it provides the endurance athlete with a more efficient “best of both worlds” scenario.

Having said that, the study impressively showed an increase in muscle cross-sectional area when using BFR, similar to that of Resistance Training. The cross-sectional area is a measure used to quantify the size of the muscle and is most often used as a measure of hypertrophy. Though not the only factor associated with hypertrophy, the evidence demonstrates that Endurance Training with BFR will provide simultaneous strength and hypertrophy gains, in significantly less time than conventional training.

This isn’t just shown in a study in isolation either. A benchmark study in the BFR research world was conducted by Ozaki and colleagues in 2014, who illustrated how 20 minutes of BFR walking for 4 days a week over 10 weeks was able to significantly increase the cross-sectional area of the thighs when compared to walking without BFR (4).

What other benefits can BFR bring? 

One of the best aspects of BFR is the number of ways it allows you to vary up your training, while still providing you with the same amount and impact, if not possibly more, of the training adaptations that you’re after.

Another benefit that can be received from BFR during injury is the blood flow restriction aspect itself. One of the blood’s primary functions is to provide nutrients to organs and tissues throughout the body. By trapping blood in the injured muscle or joint structure for a period of time, we can drastically speed up the recovery time of the local and neighbouring tissues. BFR also has an analgesic effect, reducing the perception of pain for a 24hr period. This is particularly useful for older athletes who carry chronic pain through their training.

How do you integrate BFR into your Endurance Training?

For maximising endurance adaptations, strap into settings 3 or 4 on the Hytro BFR Recovery shorts (build up to setting 4) and perform either:

– Continuous slow cardiovascular exercise for 10-15 minutes remaining strapped in for the duration of exercise.

– Intermittent exercise performing 2-3 rounds of 5 minutes with 2 minutes rest unstrapping only for the rest period. This can be any low-cadence cardiovascular exercise you like e.g bike, rower, ski erg, or walking. Walking is particularly time efficient since you can perform this at any time of the day without equipment.

What is my final conclusion?

By adding BFR to your endurance work, you can create muscular adaptations that are usually only associated with longer more intense endurance sessions. The 2 key adaptations are:

When training aerobically with BFR applied, low oxygen availability limits the muscle’s ability to receive and produce energy making the exercise workload much harder. The body responds with incredible adaptations! It extends its capillary networks (blood vessels) within the working muscles, increasing the surface area of vessels that deliver oxygen and glucose to the muscle cells. This process is called capillarisation and will ultimately lead to increases in how effectively you can get your blood to your muscles when you’re exercising, thus improving performance.

There is also an increase in the number of mitochondria in the muscle cells (the battery of our muscle), improving the muscle’s ability to create energy from the oxygen delivered by the improved capillary network. Together, this makes the muscle much more efficient at producing and using energy, improving endurance and fitness capacity.

More and more research is being released each and every day regarding BFR, both in the realms of Resistance Training, Endurance Training, and Recovery. We’re beginning to see how truly beneficial this type of training can be and the potential it has in everything from aiding rehabilitation from injuries to helping older individuals who may have limited functionality to train.

Learn more about how BFR can improve athletic performance in our How Newcastle Falcons are using Hytro for performance journal or to speak our team about a Hytro demonstration via the button below.