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Blood flow restriction is a fairly new practice in rehab though it has been in the strength and conditioning world a bit longer, as far back as 1966 in Japan.
Blood flow restriction (BFR) is the use of bands or pneumatic devices to compress blood flow in a limb limiting venous return, not arterial flow. It is not occulsion training where you are trying to achieve full limb occulsion. That is just not safe. We want the blood flow to the area we just want to limit its return. Why?
By limiting the venous return, we get an accumulation metabolic byproduct such as lactate. This causes an imbalance in our system and because our system wants to return to homeostasis (balanced) it releases more anabolic hormones to help restore the system. Hormones such as growth hormone and IFG-1. Theses hormones control protein synthesis via m-TOR and m-TORc1... protein synthesis = muscle hypertrophy (growth) over time.
BFR also makes it more difficult to recruit Type I muscle fibers therefore your body's ability to recruit more Type II fibers.
Typical these same results of a anabolic hormone state and recruitment of Type II fibers happens when we work at high intensity and high volume strength training. Think lifting at 80-95% of your 1 rep max. This is hard to consistently do due to need for recovery, joint stresses, and impossible if you are injured. Therefore, blood flow restriction allows us to create the environment our body thrives in to build muscle and strength without needing heavy volume and intensity. We are essentially tricking our brain and metabolic system into thinking we are doing the work with a lot less work or stress.
How do we use BFR?
Pneumatic cuffs are used clinically to be able to safely and effective restrict blood flow without occulsion as well as monitor exact pressure and stay within accepted guidelines based on research.
In strength and conditioning, you may see athletes using bands to restrict blood flow based on a scale of 0-10. Not an exact science but still proven to be relatively safe when applied correctly.
Cuffs can be place over clothing or underneath, based on comfort of person using them.
The cuffs are placed in 2 locations ONLY regardless of the targeted muscle group:
Upper body- placed as close to armpit as possible across biceps
Lower body- placed as close to groin as possible at top of the quad
The cuffs are inflated to 80% of complete occulsion for the lower body and 50% in the upper body. That's were pneumatic cuffs are useful because complete limb occulsion can be found through finding the pulse and waiting for it to diminish; then you can pump back up to 50-80%. (For safety, limb occulsion is found with an ultrasound doppler clinically to ensure exact measurements)
Various sets of exercises with a focus on the muscle they are wanting to target. However, multiple muscles can be affected because we are creating an environment in the blood flow which is not specific to one muscle. The athlete can also perform cardio such as biking, walking, or swimming. Cuffs typically remain in place for 6-10 minutes but can be upwards of 20 minutes depending on intensity of activity and level of athlete's fitness.
All exercises will be performed at a significant reduction intensity, <35% of 1 rep max. In many cases, this means body weight exercises or even modified body weight exercises. For example, biceps curls at 5# can be a significant challenge with BFR and push-ups may need to be on a wall or counter to allow for the rep scheme we are looking to achieve.
30-15-15-15 is what research supports to be most effective with BFR. 30 second rest between sets is the ideal rest time. If you cannot achieve at least 50 reps total, you should go down in weight.
Benefits of BFR
muscle strength and hypertrophy
non-traditional recruitment patterns (Type II first)
Increase endocrine response (hormone rich environment)
Building of non-contractile tissue
Improvement in VO2Max
Common Questions and Safety
While BFR seems awesome and a game-changer (It is!), it is still not for everyone and there are factors we have to consider before throwing cuffs on everyone.
However when performed correctly with proper devices, proper pressure management and monitoring of symptoms with proper exercise dosage, BFR is extremely safe with the greatest side effects reported being DOMS, dizziness, numbness and bruising. Dizziness, numbness and bruising are most likely due to improper use. DOMS well that's a side effect of exercise anyway!
It is important to note, you only place the bands/cuffs in the 2 locations described above! There are nerves superficial (close to the surface) that can be damaged if the cuffs are placed anywhere other than where deemed appropriate.
More is not better! More pressure does not equal more gains. The research has be adequate and deemed 50% for upper limb and 80% for lower limb.
Contraindications (don't use it)
History of DVT
Stage III or greater hypertension
High class arrhythmias
Acute sickness or fever
Early post-op (5 days)
Pregnancy
Multiple co-morbidities
Practical Uses
Obviously, the most beneficial use of BFR is when an athlete is injured and cannot lift adequate weights to maintain or gain strength (remember we need high volume/intensity). Therefore, with BFR we can safely continue to train the athlete to maintain or gain strength while injured.
This would also apply to the athlete that is post-op and has restrictions on how much weight they are "allowed" to lift. Use of BFR allows for greater muscle strength and hypertrophy in that post-surgical phase.
Or an athlete that may be suffering with a fracture or severe sprain and is not allowed to put any weight on that extremity. We can maintain and even gain strength with the use of BFR.
Can we use BFR if we are not injured? Sure!
A few examples of when/where to apply BFR to non-injured athletes:
Crossfit athletes- crossfitters may have particular weakness they want to work on but you have to monitor volume/load which cannot typically be predicted. Therefore, BFR allows this athlete to focus on making strength gains until relatively light loads so that it does not interfere with other training days or increase their risk of injury due to over-training.
Deload weeks: in deload weeks where athlete is not doing their normal volume of running or lifting, BFR is a great tool to still continue to make gains. Especially in runners, where your body need the break but some studies show walking 2 days a week for 2 weeks increased VO2 Max by 11%!! (Note: study was done in basketball players)
Bodybuilders: BFR is great to build muscle and improve hypertrophy. That's the ultimate goal for body builders- physique! So BFR can be a great supplementation to their training to make those gains.