Blood Flow Restriction Training
The problem
It is generally accepted that in order to make improvements in muscle strength and size, we need to be working at relatively high demands.
If you’ve ever taken a hiatus from the gym, you know that the reverse happens as well – as our demands go down, so do things like muscle strength and size (damn you, biology!)
We can think of this very simply as:
As demands go up, our capacity goes up in response.
As demands go down, our capacity goes down in response.
If, however, demands exceed our capacity, we may be more likely to end up with an injury.
So what does the process of injury recovery typically look like?
If you’ve ever been injured or had a surgery before, you’ll recognize this continuum.
Rest (disuse)
Passive modalities (ice, heat, massage, medications, etc)
Low intensity exercises (walking, no weights, light weights, bands, etc)
Gradual increase in intensity
Make sense, right? So what’s the issue?
Well, depending on the extent of the injury (or surgery), steps 1-3 above may take several weeks, which can be problematic considering that we can see atrophy (muscle loss) in just 10 days of detraining![1]
Given that we typically need training intensities of 65-90% of our 1RM (1 rep maximum = the maximum amount of weight that you can lift for 1 repetition on a given exercise), and it may be weeks before somebody can tolerate lifting these higher loads, it is almost inevitable that the initial phases post-injury/surgery will be 2 steps back before we ever get a chance to take a step forward.
Enter Blood Flow Restriction Training.
What is Blood Flow Restriction Training?
Blood Flow Restriction (BFR) Training, also known as “occlusion training,” is the brief and intermittent occlusion of arterial and venous blood flow using an inflatable tourniquet (similar to a blood pressure cuff) while at rest or exercising. Using this technique, you can exercise using significantly less load/weight/intensity and still achieve significant gains in muscle strength and size.[2,3]
When we exercise, we are stressing our muscles (duh). The two types of stress are mechanical and metabolic.
For simplicity’s sake, imagine that you are lifting a weight. Now imagine how different your muscles feel when you lift a heavier weight—that’s an example of mechanical tension. Now imagine that you lift that weight several times, until your muscle is fatigued and burning—you’re now experiencing metabolic stress.
In BFR Training, the cuffs are placed at the proximal end of the limb – close to the shoulder for the arm or close to the hip/groin for the leg. By decreasing the amount of arterial blood flow (blood flow into the muscle), the muscle will become hypoxic (lack oxygen). Additionally, by occluding venous return, the cuffs prevent blood from leaving the muscle which results in swelling within the limb.[4] This allows us to take advantage of both metabolic and mechanical stress, but with the use of much lighter loads.
[4,5] Although the exact mechanisms for how BFR works are not entirely understood at this time, research has suggested that the benefits of BFR are likely a result of many combined mechanisms, including:
increased fast-twitch fiber recruitment
mechanotransduction
muscle damage
systemic and localized hormone production
cell swelling
hypoxia (lack of oxygen)
production of reactive oxygen species, including nitric oxide and heat shock proteins.
Benefits of BFR Training
BFR Training can actually be used right away following injury or surgery, even if you can’t load your limb. For example, say that you just had surgery on your leg and you aren’t allowed to bear weight for 6 weeks. Instead of 6 weeks of muscle wasting, we can maintain muscle mass (and promote healing) by adding BFR…even if you aren’t doing exercises!
Then, once light exercises can be introduced, we can keep utilizing BFR to promote strength and muscle gains, similar to adaptations that would happen with higher intensity exercise.
This could potentially allow you to make a faster recovery and get back to your sport or activities more quickly.
Is BFR Training Safe?
Short answer, yes!
Now for the more nuanced response…
Because BFR training is restricting your blood flow, you want to perform BFR training with proper supervision, instructions, and equipment.
Supervision: The individual administering the BFR training should be trained to do so.
Instructions: There are specific protocols to be used in specific situations in order to safely and effectively utilize BFR training.
Equipment: While occluding blood flow is not difficult, measuring and adjusting this occlusion takes training and proper equipment. Nylon straps, elastic straps, and surgical tubing have been used by individuals in a gym setting to achieve these results, however, this may leave individuals at risk for nerve/tissue damage or cardiovascular complications.
*Contraindications for BFR training include history of blood clots (deep vein thrombosis or pulmonary embolism), heart disease, vascular disease, hypertension, poor blood flow, and pregnancy.
What does BFR NOT do?
BFR does not replace training with high loads and at high intensities. While low intensity training + BFR has been shown to result in increased muscle mass, it does not result in strength gains that are comparable to high intensity training.
BFR Training is an excellent tool that can help you through an injury and can supplement your training, but the foundation of your training plan needs to be high intensity training in order to maximize your performance.
To learn more about Blood Flow Restriction Training at ROC Physical Therapy, Click Here or Contact Us.
References:
[1] Jespersen JG, Nedergaard A, Andersen LL, Schjerling P, Andersen JL. Myostatin expression during human muscle hypertrophy and subsequent atrophy: increased myostatin with detraining. Scand J Med Sci Sports. 2011 Apr;21(2):215-23. doi: 10.1111/j.1600-0838.2009.01044.x. PMID: 19903317.
[2] Loenneke JP, Wilson JM, Marín PJ, Zourdos MC, Bemben MG. Low intensity blood flow restriction training: a meta-analysis. Eur J Appl Physiol. 2012 May;112(5):1849-59. doi: 10.1007/s00421-011-2167-x. Epub 2011 Sep 16. PMID: 21922259.
[3] Takarada Y, Tsuruta T, Ishii N. Cooperative effects of exercise and occlusive stimuli on muscular function in low-intensity resistance exercise with moderate vascular occlusion. Jpn J Physiol. 2004 Dec;54(6):585-92. doi: 10.2170/jjphysiol.54.585. PMID: 15760491.
[4] What is BFR?. Smart Tools. (2021, November 30). https://www.smarttoolsplus.com/resources/what-is-bfr/
[5] Pearson SJ, Hussain SR. A review on the mechanisms of blood-flow restriction resistance training-induced muscle hypertrophy. Sports Med. 2015 Feb;45(2):187-200. doi: 10.1007/s40279-014-0264-9. PMID: 25249278.
