In our constant pursuit of athletic excellence, we have always been on the lookout for ways to optimize training and recovery. When it comes to performance, we have learned how to take a healthy athlete and make them even bigger, stronger and faster. We manipulate reps and sets across multiple training sessions like a Fields Medal mathematician, fine tune lifting technique like a mechanic working on a Formula 1 race car and spend hours upon hours devising the ‘best’ meal plan down to the microgram like a mad scientist concocting their latest experiment.
Just as performance training has evolved over the centuries, the world of rehab and recovery has pushed forward as well. We now know that most injuries that occur in the weight room are due to poor movement/technique or inappropriate loads when lifting. Over time poor movement and/or loading habits create tiny amounts of trauma that eventually cumulate and lead your body over the proverbial ‘tipping point’ into injury. This understanding allows us to therefore address the root cause of injury throughout the entire “kinetic chain” rather than focus on the site of symptoms.
This “movement based” approach allows us to be significantly more effective at recovering from intense training and with fixing injuries. Within this approach, there are tools that can help us achieve our performance or rehab goals a little faster. Once such tool is blood flow restriction training. Blood flow restriction (BFR) has steadily been gaining national recognition and popularity. As you’ll soon see, BFR can help optimize recovery to an even greater degree in the right circumstances when used apppriately.25
Also known as occlusion, hypoxic or KAATSU training, BFR is the process of restricting blood flow out of the working muscle by wrapping a tourniquet-like strap to the top of your arms or legs. The tight material allows blood to flow into your arms or legs through arteries but limits the amount of blood that can leave the limbs through your veins. This restriction creates numerous changes within the body during exercise that has been found to increase muscle strength/size, optimize recovery from injury and enhance aerobic capacity.
And here’s the kicker, it does this all with light weights and a higher rep scheme than one would normally use in a traditional strength protocol. As you will learn in this blog, BFR training can be a gamechanger for an athlete looking to maintain strength when they can’t lift heavy due to injury, enhance recovery from training and improve endurance without spending countless hours on a bike.
So How Does It Work?
Dr. Mario Novo (one of the foremost researchers on the topic) explains that BFR, “simply changes the environment your brain thinks you’re actually in.” Basically, you trick your body into thinking it’s performing very intense exercise (when you’re not) and it responds accordingly. Here’s how it is believed to work scientifically.
One of the first things you’ll experience when using BFR is an increase in your heart rate. The tightly fitting cuffs essentially trap blood within your arms or legs and create a low-oxygen (hypoxic) environment. Your body senses this drop in oxygen within the muscles and responds by increasing your heart rate in an effort to pump more blood (and therefore oxygen) to the working muscles.
As you continue to exercise, you’ll then start to feel an extreme muscle “pump” sensation. Imagine for a moment the most intense muscle pump you’ve experienced while lifting, and then multiply it by 10. It’s that intense if you’re performing BFR correctly. This is where the “magic” of BFR starts to happen. This pump sensation is the feeling of fluid shifting into the muscle cells (a process called cellular swelling).6 Human growth hormone levels begin to rise, lactic acid starts to buildup and a gene within your body called mTOR is stimulated (all essential factors in supporting muscle/bone growth and repair).7,8,33
On a cellular level, numerous tiny cells called satellite cells simultaneously converge to help repair damaged tissue and build new muscle or bone. The building fatigue in your arms or legs then tricks the brain into thinking you’re lifting heavy weight, which causes your body to start recruiting more and more high intensity “fast twitch” type 2 muscle fibers. Here’s why this is so interesting.
During a normal resistance training session, the amount of weight you lift and how fast you move the weight determines the amount and type of muscle fibers your body activates. For example, if you were to perform a set of 10 slow tempo squats with an unloaded barbell, your body would recruit predominantly low intensity type 1 or “slow twitch” muscle fibers. If you were to place 400 lbs. on the bar, your body would sense the large force pushing into your upper back and signals your brain to respond accordingly. A high amount of type 2 muscle fibers would be recruited to perform the heavy lift. As you attempt to lift more weight or move a weight faster, your body will respond accordingly by recruiting more type 2 “fast twitch” muscle fibers in order to safely complete the movement. Training with BFR flips this paradigm upside down and allows an athlete to recruit and activate high-load muscle fibers without the heavy weight.
When Would You Use It?
Over the past few decades there have been hundreds of published scientific articles detailing the many benefits and uses of BFR (from those on bed rest due to injury/illness to the elite athlete looking to maximize their performance). These benefits include (but are not limited to):
- Increasing Strength
- Increasing Muscle Size (Hypertrophy)
- Optimizing Rehabilitation from Injury
- Post Training Recovery
- Improving Aerobic Endurance/Capacity
With these qualities in mind, let’s now discuss some practical applications for the use of BFR and how it could be used by a strength athlete (weightlifter, powerlifter, CrossFitter, etc.).
The Injured or “Load Compromised” Athlete
It is universally recognized that in order to substantially increase strength and muscle size, lifts should be performed with at least 70%-80% of an athlete’s ones 1-repetition maximum lift (1RM).1 However, there are situations that arise in which heavy lifting is not possible (for example, an athlete recovering from an ACL surgery or an athlete dealing with a stress fracture in the low back). BFR can be used during this time in conjunction with a ‘movement based’ rehab program to maintain strength and muscle size without having to lift heavy.13-18,51 Let me explain.
When an athlete is injured, this will affect his/her ability to lift without pain. The main goal of any rehab program is to decrease pain and facilitate healing without causing additional harm/damage to the body. If you exercise too intensely during this time, you place excessive load on the damaged tissue and risk making things worse (an athlete recovering from injury is therefore considered to be “load compromised”). This is why we shouldn’t perform heavy squats 4 weeks after ACL reconstruction surgery or do a heavy bench press workout 2 weeks after a partial pec tear.
A common recommendation from many medical professionals for an acute injury is to rest, ice and immobilize the injured area. However complete rest can be a recipe for a delayed and even failed recovery. Complete rest typically leads to loss in strength and muscle atrophy. In fact, you can see a significant decline in both of these areas in as little as two weeks of complete rest!
BFR training provides athletes a unique opportunity to promote muscle growth and ward off unwanted loss in muscle size (called ‘disuse’ atrophy) when you can’t lift heavy due to pain/injury. In fact, a “load compromised” individual can increase their muscle size and regain their prior strength with as little as 20-30% of their 1-rep max when using using BFR training.10,11,15,16,26,27
Injured athletes are therefore able to optimize the rehabilitation process and find benefits normally associated with heavy lifting without subjecting their body to loads that would otherwise amplify their current symptoms and risk further injury.25,28 BFR essentially becomes a bridge between the established rehab practices and the strength & conditioning world.
For example, during the first few weeks following any knee surgery (such as an ACL reconstruction or meniscus scope/repair) an athlete will often perform exercises such as straight leg raises, mini squats with bodyweight alone and leg press with very low-load.30 Using BFR with these exercises allows the athlete to optimize training by maximizing the strength and hypertrophy stimulus to the body. All of a sudden, your body responds to a leg press with 50 pounds as if it is performing the exercise with 300 lbs. (thus “tricking the body” into receiving some of the benefits of heavy training until the time you can return to traditional strength training again).
Research has also shown that BFR can even help decrease pain (called a hypoalgesia effect) for up to 45 minutes!35 This could open a window of opportunity for an athlete to complete exercises in a pain-free environment that would normally have elicited mild-moderate pain.
BFR could also allow a “load compromised” athlete the ability to optimize training of uninjured areas of their body. Take for example, an athlete with a low back injury is currently unable to back squat or deadlift without pain. This athlete could maintain strength and muscle size in his legs by using BFR with accessory exercises like the leg press, knee extensions or belt squats. Once their spine has healed and pain has resolved, this athlete can resume the back squat and deadlift exercises. This is a method elite powerlifter Blaine Sumner is currently using to maintain strength as much as possible in his journey to returning to his prior 1000+ lb. squat as he rehabs a back injury.
The “Load Managed” Athlete
As mentioned early in this article, injuries in the weight room can be the result of problems with technique or excessive loads when lifting. This means an athlete could develop an achy knee or a sore elbow simply because they cannot recover from the amount of weight (intensity and/or volume) they are lifting throughout the week. In this case, it’s not necessarily a technique issue but a load accumulation problem. In these cases, a complete stop from training is usually not the best course of action. Rather we just need to adjust the amount of load that is accumulated on the body during the course of the week or month. This is where BFR enters the conversation.
Research has shown BFR with light weights does not lead to muscle damage or excessive stress on connective tissues when compared to lifting with heavy weights.31 BFR training provides a unique opportunity for load compromised athletes to still train in order to maintain strength/hypertrophy.
In fact, there have even been studies performed that looked into low-load BFR resistance training combined with traditional heavy weight training. One such study in 2011 divided its participants into three training groups and had them all perform the bench press exercise.9 One group performed a customary high-load resistance training protocol three days a week. Another performed only low-load BFR with 30% of their 1RM. The last group performed the high-load training once a week and the low-load BFR work the other two days.
At the study’s conclusion, the researchers found the high-load resistance training group and the combined training group were able to make significant improvements in 1-rep max strength. The results of the study show that it is possible to modify how often an athlete lifts heavy and still find progress. Having the ability to lift heavy once a week vs three times per week could be a great option for an athlete dealing with load-related injuries.
The Healthy Athlete (Recovery Training)
In terms of recovery, BFR has shown to have significant impact on:
- Immediate Recovery Between Training Sessions
- Intermittent Recovery After Training Blocks
The strategies we use to recover between training sessions can make the difference between failure and success in many situations. Nowadays most coaches and athletes understand that optimal recovery is much more than relaxing on your couch watching Netflix for 8 hours on your “off day.” However, the question then becomes, “What should I do for recovery?”
One study in 2020 compared BFR, a neuromuscular electrical stimulation or NMES device (such as the Marc Pro, PowerDot or Compex) and 10 minutes of “active recovery” cycling on a bike on subsequent power output performance.49 A group of endurance athlete performed two cycling time trials separated by 45 minutes of recovery. The BFR group rested with inflated cuffs on their legs for three sets of five minutes (each set separated by five minutes). The NMES group applied their treatment to their calf muscles (with enough stimulation to make their muscles contract) for 30 minutes. The active recovery group remained seated on their bikes and performed a low-intensity cycle for another 10 minutes before resting for another 2- minutes prior to the next time trial.
The researchers found that BFR was just as effective as the active recovery and the NMES to enhance clearing of the metabolic waste produced by exercise and enhance maximal performance.50 I’m not suggesting that BFR is the new gold standard in recovery. However, we can confidently say that BFR is a helpful tool in aiding recovery (we’ll talk more about the specific protocols for this purpose later in this article).
While the topic of recovery between training sessions is topic many coaches are well versed on, the idea of how to recover after intense training blocks is not. This is because strength athletes love lifting heavy. Unfortunately, their drive for excellence comes at the fault of not always knowing when to take a step back and allow the body to recover. From an early age, athletes are told “more is better”. This mindset has created a cycle where athletes continue to lift and push until they literally break. It is not until something usually goes wrong and an injury sets in and affects performance that athletes finally look to change up their training program.
In order to stop this viscous cycle of lift-lift-lift, break, we can optimize our training with planned recovery periods. For example, this may look like 2-3 weeks (or longer for certain athletes based on individual needs) of low-load training following a competition or after ending a training block cycle and before starting another.
It then becomes a question of how to optimally train during these periods of planned de-load. You see, our body does an amazing job of adapting to the stresses applied to it. The cells that make up our muscles, tendons and bones will either respond positively or negatively to the amount of stress or type of stress. For example, our tendons become stronger in response to heavy training by increasing their stiffness levels.26 By routinely subjecting their tendons to high levels of load through proper training programs, athletes have the ability to raise the “load tolerance” level of their tendons.
However, if an athlete who is able to tolerate a ton of load day in and day out took a long break from training (two or more weeks for example to lay on the beach) and all of a sudden jumped right back into a relatively normal training program (“normal” being relative to what they were used to), they could potentially overload their tendons. This is because their tendons would become somewhat deconditioned over the extended break, adapting their tissues to a lower “load capacity” level. The amount of de-load time for the tendon to lower in capacity will be dependent on the athlete’s age, training history, ability to recovery and quality of nutrition/hydration. For instance, older athletes with a history of tendon/joint injuries will need to slowly ramp up to prevent aggravation of their pain/symptoms. Certainly, genetic makeup plays a factor in higher tendon resiliency in certain athletes vs others.
BFR can therefore be used as a way to safeguard against a complete de-load during times away from the gym (such as a vacation) for a healthy athlete. An athlete can use the BFR strength protocols (something we’ll go over soon) with bodyweight or very light weights as a way to maintain their strength and size while allowing the body to heal and recover from rigors of the prior training cycle before jumping into another.
The Healthy Athlete (Enhancing Performance Training)
A very important side note that I need to mention is that BFR is not a replacement for your usual heavy lifting if you’re a healthy athlete. With that being said, BFR can be useful in getting athletes ready for their usual workload.
As we discussed prior, BFR allows you to regain or maintain strength by effectively tricking your body into thinking it’s performing very intense exercise. Using BFR with 20%-30% of your 1RM on a leg press is going to recruit more type 2 muscle fibers in your quads than without BFR (and your body will have a physiological response that is similar to what you would see if you were to be performing the movement with 80% of your 1RM).
However, picking up a heavy barbell is much more than activating a lot of type 2 muscle fibers. Lifting heavy requires coordination and stability of the entire body working together. Every muscle from your feet on up must fire at the right time, right intensity and in the right sequence in order to complete the lift correctly. BFR should be viewed as a supplement and not as a replacement to heavy lifting. For example, in one study the group that only performed the low-load bench press with BFR training did not see any significant improvements when retesting their 1RM. So, if you are in the sport of powerlifting, Olympic Weightlifting or CrossFit, you NEED to move heavy weight in order to break new PRs!9
That being said, there is still a place for BFR in the training of healthy athletes:
- Warm Up
- Improving Cardiovascular Endurance
Research has shown that BFR training can neurologically increase muscle activation and coordination without over fatiguing the body.33,36 Some experts in BFR believe that BFR training can be a valuable part of dynamic warmups to enhance training outcomes.23 In fact, elite powerlifter Chris Duffin used BFR as a part of his warm-up in his quest to squatting 1000 lbs. for 3 reps!24
One of the proposed ways BFR can enhance performance through a warmup is through a concept called post-activation potentiation (PAP). This phenonium has been widely studied in sport science over the past decades.
One of the ways PAP is believed to work is by “turning on” fast twitch muscle fibers with a “conditioning” exercise that temporarily opens a window for enhanced power production.42 For example, if someone performs a max or near max exercise (such as a heavy back squat of >80% of their 1 RM) and then immediately performs a jump or sprint, research shows the fatigue of the first exercise actually enhances power production on the second. 38,39
Because BFR exercises with lighter loads (such as bodyweight) can also induce an earlier onset of high-threshold motor units, it has the potential to elicit more sustained power improvements after performing.40,41 For example, one study performed in 2019 compared two groups of athletes during a vertical jump test.37 Both groups warmed up with a few sets of bodyweight lunges (one with BFR and one without) before testing their vertical jump height, flight time and power production. They found that all performance measures were significantly improved in the group that used BFR even 15 minutes after the warmup! The non-BFR group did not find any improvements. The results of this study show that BFR can be used during a warmup routine as a practical and effective tool for improving power development.
Another way in which we can use BFR for a healthy athlete is to improve their endurance.46,47 I know many powerlifters and weightlifters could care less about endurance and will want to skip this part of the article. Hold your horses! I promise you’ll find the next part interesting.
If a strength athlete improves their cardiovascular endurance capacity, they increase their potential to recover faster between sets and training days! When most strength athletes hear the phrase “cardiovascular endurance,” they envision a skinny long-distance runner spending countless hours on a treadmill. This picture quickly evokes fear of losing the strength and muscle you worked so hard to build. Although science has proven that marathon running will negatively impact a powerlifter’s squat/deadlift numbers, we shouldn’t entirely neglect the benefits of endurance training. Quite the opposite. By using BFR with short 10 to 15 minutes walks or bike rides we can bring out similar cardio improvements while eliminating the harmful effects of long duration endurance training on the strength building process. In addition to improving heart capacity/efficiency BFR will only improve peripheral muscle endurance.
For example, in 2010 a research study was performed that looked into the effects of low-intensity aerobic exercise with and without BFR.5 One group of participants cycled with BFR at 40% of their VO2max three times a week for 15 minutes, while another cycled without BFR at the same intensity but for a much longer duration (45 minutes). After 8 weeks they compared the groups and found significant differences! The BFR group (who cycled for 66% less overall time) saw a 6.4% increase in their VO2max, a 15.4% improvement in their time to fatigue, an increase in muscle hypertrophy as well as increased knee isometric strength! The control group saw no changes.
The benefits from BFR training extend from amateurs to even the most elite athletes. One study in 2020 compared 31 elite rowers training with and without BFR during their training (two sets of 10 minutes rowing at a low intensity, three times a week for 5 weeks).45 After 15 sessions the BFR group showed a remarkably higher VO2 max showing that BFR with low-intensity exercise can lead to significantly improved aerobic endurance even in highly trained healthy athletes.
How to Perform
Finding Your LOP
In order for BFR to be effective, a strap or band must be secured firmly around the top of your thigh or arm. There are a few different methods and devices available to perform BFR and you need to understand the differences.
The simplest method is to fasten a strap around the arm or leg and pull it to a 7 out of 10 level of tightness (aka “practical” BFR). This method is very easy to perform and also cost effective. However, there are some big downsides as you’ll soon see.
The largest drawback to using a knee wrap to perform BFR is that you could potentially restrict blood flow in both your arteries and veins (arteries bring blood to the working muscles while veins are what take it away). Remember, to allow the “magic” of BFR to work effectively we need to create a swelling response in the limbs by allowing blood to get to the working muscles but limit the veins from returning blood to the heart.
Also, the difficult part of saying “wrap your leg or arm to a 7 out of 10 level of tightness” is that it’s extremely subjective. In the same way that many of my patients mysteriously all have a “high pain tolerance,” it’s common to see many athletes underestimate their wrapping intensity and over apply “practical” BFR.
Simply put, this method of BFR is not very reliable .48 Using a simple knee wrap doesn’t allow for optimal restriction of blood flow or consistency between your training sessions (as wrapping just a little more or less tight than the day before could have drastic effects to your training outcomes).
One step better would be to use an inflatable BFR cuff that allows you to increase the pressure to a certain set-point with a hand pump (just as someone would do when manually taking your blood pressure). These cuffs allow you to safely and reliably place the same amount of desired pressure on your body each training session.
This method will allow you to be consistent with the pressure from session to session. The downside is that you won’t know the percentage of limb occlusion. Here’s what I mean.
Let’s say you and your friend are going to do some light-weight squats with the BFR cuffs around your thighs. If you both set the pressure of the cuffs at 150 mmHg of pressure, you may have completely different experience during the exercise than your friend. This is because thigh circumference will have a direct effect on cuff pressure. Basically, those with bigger legs need more pressure than in order to reach the same level of blood flow restriction as someone with smaller legs. Therefore, using an arbitrary cuff pressure (such as 150 mmHg) may be beneficial for some but not for others.25
Therefore, in order to get the best results from BFR training you need to inflate your cuff pressure to a personalized set pressure point based off your individual limb occlusion pressure (LOP). This ensures we safely “shut off” the exact amount of blood flow in and out of the arms or legs that we want for the desired training effects. For example, it is recommended that most use only 30-50% of their LOP with upper body exercise while you may need 50-80% to optimize the results in lower body training. Knowing your individual LOP allows you and your friend to both get the exact same benefits of BFR training by setting the pressure of the cuffs to a personalized percentage of your LOP.
To find your LOP, start by placing the inflatable cuff around your leg or arm in the desired position (as close to the joint as possible while still being comfortable). For the leg, find the pulse of the posterior tibial artery that runs just behind your medial ankle bone (malleolus). For the arm, find the radial pulse on the front side of your wrist (on your thumb side). Many BFR units will come with a handheld doppler that will allow you to hear the pulse of the posterior tibial artery or radial artery in your arm.
Start inflating the cuffs slowly until the pulse vanishes. Make a note of this pressure level (in mmHg) as this the LOP for your arm or leg. You will then set your cuff pressure at a percentage of this level during your chosen exercises.
There are also new units just now coming to market that can allow an individual to personalize their BFR settings without the use of a doppler unit! One such example is the SmartCuffs by SmartTools (the exact unit I use in clinic with my patients).
We have to follow the right protocol to achieve adaptations in strength, cardiovascular endurance and hypertrophy.43 Here are four of the most common BFR training plans that can be implemented by athletes and coaches:
- Strength/Hypertrophy Training
- Cardiovascular Endurance Capacity
- Post-workout Recovery (or Passive Maintenance)
To use BFR as a warmup, simply perform a few sets of “low-load” movements before loading up the barbell. This should not be an extremely fatiguing protocol. Here’s an example:
Squat Warm Up:
- Dynamic Warm Up: A five minute walk followed by mobility work for the hips and ankles and the McGill Big 3 for priming core stability.
- BFR Warm Up: 3-5 sets of 15 bodyweight “air squats” with 60% LOP with 30 seconds rest between each set.
- Squat Workout: start with the open barbell and then add load.
The standard routine to improve strength or hypertrophy with BFR is a simple 4 set protocol. The first set is 30 reps and the next three sets are 15 reps, each with 30 seconds rest in between. During your first time performing this protocol, start with 60% LOP for the legs or 40% for the arms and lift 20-30 of your 1RM for the chosen exercise. Be advised, this is very difficult and takes a lot of mental fortitude to push through. As you become more accustomed to using BFR, you can start to increase the amount of weight lifted to 40% of your 1RM but no more than 50%. As you get acclimated to BFR training and build your tolerance, you can gradually increase the LOP in the upper body to 50% and lower body to 80%.
If you’re performing the exercise protocol at the right intensity and occlusion pressure, the very last set should be extremely difficult and cause you to almost fail before completing the full 15 repetitions. However, if you find yourself not being able to complete the earlier sets of the protocol because it is too intense you need to drop weight and/or occlusion pressure.
When deciphering how to program BFR for an injured athlete start with compound movements and then move to more isolated assistant movements. You can also think about progressing from closed-chain exercises (arms/legs in contact with the ground such as a squat) to open-chain exercises (where your arms/legs are not fixed to the ground such as a straight leg raise). Here are some example training recipes:
Example 1: Athlete with Knee Injury Who Cannot Squat Deep
Exercise 1: Box squat using 20-40% of 1-rep max.
Exercise 2: Touchdown single leg squats off small box or single-leg leg press.
Exercise 3: Straight leg raise or bridge
Example 2: Master athlete who trains heavy but supplements their heavy lifting with BFR training.
Exercise 1: Bench or Overhead Press with 20-40% of 1-rep max.
Exercise 2: Suspension Trainer Rows
Exercise 3: Triceps pull downs with 30% of 1-rep max.
Make sure to use the 30/15/15/15 protocol for every exercise. Your tempo of movement should be a one to two second raise and lower without any pauses (often written as a 1-0-1 or 2-0-2). Make sure you get through all four sets before deflating the cuffs. Rest for one minute before going to the next exercise.
As we discussed before, the great thing about using BFR to build aerobic capacity is that you don’t need to spend countless hours doing low-intensity training. Here’s how you can program this at home. You can ride a stationary bike, rowing machine or walk for 10-20 minutes a few times a week with the BFR cuffs on. The cuffs should be set between 60-80% LOP. The pace doesn’t have to be very intense. You should strive for a pace that is slightly above a conversational pace which would provide massive results. Be advised, the BFR cuffs will give you an intense burning muscle pump during the ride/walk!
Workout Recovery (or Passive Maintenance)
Here’s how you can enhance your recovery with BFR. While sitting in a relaxed position (or lying flat) increase the BFR cuffs anywhere between 80% LOP and full occlusion for 5 minutes. During this time, you can place NMES pads on your legs or just perform 10 isometric contractions of your quad muscles for 5 second holds every minute. After 5 minutes, deflate the cuffs for 1 minute before reapplying for another 2 rounds.
This exact same protocol can be used as “passive maintenance” for those directly after a surgery. Let’s say you’ve just had a big surgery (such as a meniscus or ACL repair) and you’ve been told not to put weight through your leg for a few weeks. When weight bearing exercises are not yet possible due to pain or surgical restrictions, you can still use BFR. This protocol of high-level cuff occlusion for 5 minutes at a time can slow down the muscle atrophy that natural occurs when the leg is non-weightbearing for a while.
Frequency and Progression
In order to get the maximum benefit from BFR training you need to perform it frequently (at least 2-3 days a week).28Completing BFR training once a week is simply not enough to get significant results.
Just as with programming a strength and conditioning program for a healthy athlete, there is no “golden rule” for how progression must look. That being said, research does give us some insight. For example, in one study researchers divided participants into different groups.52 The standard BFR strength protocol was performed with either 20% or 40% of their 1RM and at either 40% or 80% LOP.
The study showed that if exercising at very low intensity (20% of 1RM), it’s best to up your BFR pressure to 80% LOP. If you’re using a heavier weight (40% of 1RM), you likely won’t see any more benefit by maxing out the LOP as well. This was confirmed by another study that found increasing the cuff occlusion pressure from 40-90% did not promote more muscle mass growth when lifting 30% of their 1RM.53 If you’re lifting extremely light weights, keep the pressure high and as you increase the weight you can keep your cuff pressure at a moderate level (erring on the side of caution) and still get amazing results.
Remember that the ultimate goal of BFR training is to use lighter weights to trick the brain in to thinking that it is exercising more rigorously than it actually is. While increasing load over time can be helpful, don’t get carried away. Going over the recommended 20-40% of your 1-rep max will be extremely uncomfortable and limit any potential benefits of BFR training.
How Safe Is BFR?
The initial thought of placing tourniquet-like cuffs around your limbs and tightening them to the point of restricting blood flow raises concerns for some. There are skeptics who believe BFR could damage the underlying blood vessels or nerves, or even worse increase risk of harmful blood clots! However, research has demonstrated that when BFR is applied correctly it is actually very safe for most people.43,44
In 2006 a study was released that looked into the relative safety of BFR training. Of the 105 facilities that took place in the study (including over 30,000 BFR sessions) the only significant cause for concern was of light bruising at the site of the tourniquet cuff for a few individuals.19
In 2018, another group of researchers compared low-load BFR training to traditional high-load weight training over 4 weeks.20 At the study’s conclusion, they found both groups were able to see significant strength improvements without any negative physical side effects. They also found the BFR training did not harm blood vessels, nerves, or lead increase risk of blood clots.20
In fact, traditional resistance training already results in occlusion of your blood vessels!21 BFR is only mimicking this natural reaction and doing it at a much lower intensity. In respects to placing stress on the heart, BFR training with low load may be a safer option than training with heavy resistance.
When you lift over 80% of your 1-rep max, your blood pressure more than doubles!21 In fact, one research study found the average blood pressure in a group of experienced bodybuilders performing heavy leg press rose to 350/250 mmHg (resting “normal” for a healthy adult is 120/80mmHg). These extreme elevations in blood pressure are believed to be due to the mechanical compression of the blood vessels when your muscles contract.
Conversely, research has shown that BFR with light weight only slightly increases blood pressure (on average never rising over 182/105 during exercise).22 This is clear evidence that lifting heavy results in a significantly greater rise in blood pressure compared to low-load BFR.
Now, it should be pointed out that every one of these prior studies were performed on relatively healthy individuals. It is recommended that you first consult with a medical physician before trying BFR if you have any of the following safety concerns:
- History of heart issues (atrial fibrillation, heart failure, arrhythmias or coronary ischemia, etc.)
- History of DVT (deep vein thrombosis)
- Elevated blood pressure or hypertension
- Impaired Circulation
- Open wounds
- Poor clotting abilities
If you want to increase strength, grow larger muscles or build your endurance, you need to stress your body. Without stress, there can be no progress. The question then becomes, “How do you optimally stress the body in order to meet your physical goals?”
The goal with BFR training is not to try and re-invent the wheel. Lifting heavy is always going to be the most effective method to gain strength. You can’t rely solely on BFR training with light weights and expect to break your PR on the back squat. When used appropriately, BFR training does allow us to maintain muscle strength/hypertrophy during periods of injury and also boost recovery for healthy athletes.
I hope you now have a better understanding of how BFR training works and how/when to apply it.
Until next time,
- ACSM. American College of Sports Medicine position stand: progression models in resistance training for healthy adults. Med Sci Sports Exerc 2009; 41(3):687-708
- Takarada Y, Takazawa H, Sato Y et al. Effects of resistance exercise combined with moderate vascular occlusion on muscular function in humans. J Appl Physiol 2000;88(6):2097-2106
- Laurentino Gc, Ugrinowitsch C, Roschel H et al. Strength training with blood flow restriction diminishes myostatin gene expression. Med Sci Sports Exerc. 2012;44(3):406-412
- Kubo K, Komuro T, Ishiguro N et al. Effects of low-load resistance training with vascular occlusion on the mechanical properties of muscle and tendon. J Appl Biomech. 2006;22(2):112-119
- Abe T, Fujita S, Nakajima T, Sakamaki M, Ozaki H, et al. Effects of low-intensity cycle training with restricted leg blood flow on thigh muscle volume and VO2max in young men. J Sports Sci Med. 2010; 9(3):452-458
- Loenneke JP, Fahs CA, Rossow LM, Abe T, Bemben MG. The anabolic benefits of venous blood flow restriction training may be induced by muscle cell swelling. Med Hypotheses. 2012;78(1):151-154.
- Fry CS, Glynn EL, Drummond MJ, Timmerman KL, et al. Blood flow restriction exercise stimulates mTORC1 signaling and muscle protein synthesis in older men. Journal of Applied Physiology. 2010; 108(5):1199-1209.
- Takano H, Morita T, Iida H, Asada KI, Kato M, et al. Hemodynamic and hormonal responses to short-term low-intensity resistance exercise with the reduction of muscle blood flow. European Journal of Applied Physiology. 2005;95(1):65-73.
- Yasuda T, Ogasawara R, Sakamaki M, Ozaki H, et all. Combined effects of low-intensity blood flow restriction training and high-intensity resistance training on muscle strength and size. Eur J Appl Physiol. 2011;111(10):2525-2533
- Sudo M, Ando S, Kano Y. Repeated blood flow restriction induces muscle fiber hypertrophy. Muscle Nerve. 2017;55(2):274-276
- Slysz J, Stultz J, Burr JF. The efficacy of blood flow restricted exercise: A systematic review & meta-analysis. J Sci Med Sport. 2016; 19(8):669-675
- Yasuda T, Fujita S, Ogasawara R, Sato Y, Abe T. Effects of low intensity bench press training with restricted arm muscle blood flow on chest muscle hypertrophy: a pilot study. Clin Physiol Funct Imaging. 2010;30(5):338-343
- Shinohara M, Kouzaki M, Yoshihisa T, Fukunaga T. Efficacy of tourniquet ischemia for strength training with low resistance. Eur J Appl Physiol Occup Physiol 1998: 77: 189–191.
- Nicholas SJ, Tyler TF, McHugh MP, Gleim GW. The effect on leg strength of tourniquet use during anterior cruciate ligament reconstruction: a prospective randomized study. Arthroscopy 2001: 17: 603–607
- 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: 54: 585–592.
- Takarada Y, Sato Y, Ishii N. Effects of resistance exercise combined with vascular occlusion on muscle function in athletes. Eur J Appl Physiol 2002: 86: 308–314.
- Madarame H, Neya M, Ochi E, Nakazato K, Sato Y, Ishii N. Cross-transfer effects of resistance training with blood flow restriction. Med Sci Sports Exerc 2008: 40: 258–263.
- Clark BC, Manini TM. Blood flow restricted exercise and skeletal muscle health. Exerc Sport Sci Rev 2009: 37: 78–85.
- Nakajima T, Kurano M, Iida H, Takano H, Oonuma H, Morita T, Meguro K, Sato Y, Nagata T. Use and safety of KAATSU training: results of a national survey. Int J KAATSU Training Res 2006: 2: 5– 13
- Clark BC, Manini TM, Hoffman RL, Williams PS, et aal. Relative safety of 4 weeks of blood flow-restricted resistance exercise in young, healthy adults. Scand J Med Sci Sports. 2011;21(5):653-662
- MacDougall JD, Tuxen D, Sale DG, Moroz JR, Sutton JR. Arterial blood pressure response to heavy resistance exercise. J Appl Physiol. 1985;58(3):785-790
- Takano H, Morita T, Iida H, et al. Hemodynamic and hormonal responses to short-term low-intensity resistance exercise with the reduction of muscle blood flow. Eur J Appl Physiol. 2005;95(1):65-73
- M. Novo, email to author, May 20, 2020.
- C. Duffin, email to author, January 21, 2020.
- Hughes L, Paton B, Rosenblatt B, Gissane C, Patterson SD. Blood flow restriction training in clinical musculoskeletal rehabilitation: A systematic review and meta-analysis. Br J Sports Med. 2017;51:1003-1011
- Burgomaster KA, Moore DR, Schofield SM, et al. Resistance training with vascular occlusion: metabolic adaptations in human muscle. Med Sci Sports Exerc. 2003;35:1203-8
- Loenneke JP, Kim D, Fahs CA, et al. Effects of exercise with and without different degrees of blood flow restriction on torque and muscle activation. Muscle Nerve. 2015;51:713-21
- Loenneke JP, Wilson JM, Marin PJ, et al. Low intensity blood flow restriction training: a meta-analysis. Eur J Appl Physiol. 2012a;112:1849-59
- McEwen JA, Owens JG, Jeyasurya J. Why is it crucial to use personalized occlusion pressures in blood flow restriction (BFR) rehabilitation? J Med Biol Eng. 2018:1-5
- Hughes L, Rosenblatt B, Paton B, Patterson SD. Blood flow restriction training in rehabilitation following anterior cruciate ligament reconstructive surgery: A review. Techniques in Orthopaedics; 2018,33(2):106-113
- Loenneke JP, Thiebaud RS, Abe T. Does blood flow restriction result in skeletal muscle damage? A critical review of available evidence. Scan J Med Sci Sports. 2014;24(6):e415-422
- Scott BR, Loenneke JP, Blood flow restricted exercise for athletes: a review of available evidence. J Sci med Sport. 2016;19(5):360-7.
- Takarada Y, Nakamura Y, Aruga S, Onda T, Miyazaki S. Rapid increase in plasma growth hormone after low-intensity resistance exercise with vascular occlusion. J Appl Physiol. 2000;88(1):61-5.
- Yasuda T, Brechue W, Fujita T, Shirakawa J, Sato Y, Abe T. Muscle activation during low-intensity muscle contractions with restricted blow flow. J Sports Sci. 2009
- Korakakis V, Whiteley R, Epameinontidis K. Blood flow restriction induces hypoalgesia in recreationally active adult male anterior knee pain patients allowing therapeutic exercise loading. Phys Ther Sport. 2018;32:235-342
- Wilson JM< Lowery RP, Joy JM, Loenneke JP, Naimo MA. Practical blood flow restriction training increases acute determinants of hypertrophy without increasing indices of muscle damage. J Strength Cond Res. 2013;27(11):3068-3075
- Doma K, Leicht AS, Boullosa D, Woods CT. Lunge exercises with blood-flow restriction induces post-activation potentiation and improves vertical jump performance. Eur J Appl Physiol. 2020;120(3):687-695
- Wilson JM, Duncan NM, Marin PJ, Brown LE, Loenneke JP, Wilson SM, Jo E, Lowery RP, Uginowitsch C. Meta-analysis of postactivation potentiation and power: effects of conditioning activity, volume, gender, rest periods, and training status. J Strength Cond Res. 2013;27(3):854-859.
- Seitz LB, Haff GG. Factors modulating post-activation potentiation of jump, sprint, throw, and upper-body ballistic performances: a systematic review with meta-analysis. Sports Med. 2016;46(2):231-240
- Moritani T, Sherman WM, Shibata M, Matsumoto T, Shinohara M. Oxygen availability and motor unit activity in humans. Eur J Appl Physio Occup Physiol. 1992;64(6):552-556.
- Fatela P, Mendonca GV, Veloso AP, Avela J, Mil-Homens P. Blood flow restriction alters motor unit behavior during resistance exercise. Int J Sports Med. 2019:40(9):555-562.
- Sale DG. Postactivation potentiation: role in human performance. Exerc Sport Sci Rev. 2002;30(3):138-43.
- Patterson SC, Hughes L, Warmington S, Burr J, et al. Blood flow restriction exercise position stand: considerations of methodology, application, and safety. Front Physiol. 2019;10(533):1-15
- Minniti MC, Statkevich AP, Kelly R, Rigsby VP, et al. The safety of blood flow restriction training as a therapeutic intervention for patients with musculoskeletal disorders. Am J Sports Med. 2020;48(7):1773-1785.
- Held S, Behringer M, Donath L. Low intensity rowing with blood flow restriction over 5 weeks increases VO2 max in elite rowers: a randomized controlled trial. J Sci Med Sport. 2020;23(3):304-308.
- Formiga MF, Fay R, Hutchinson S, Locandro N, et al. Effect of aerobic exercise training with and without blood flow restriction on aerobic capacity in healthy young adults: a systematic review with meta-analysis. Int J Sports Phys Ther. 2020;15(2):175-187
- Bennett H, Slattery F. Effects of blow flow restriction training on aerobic capacity and performance: a systematic review. J Strength Cond Res. 2019;33(2):572-583.
- Bell ZW, Dankel SJ, Spitz RW, et al. The perceived tightness scale does not provide reliable estimates of blood flow restriction pressure. J Sport Rehabil. 2019;29(4):516-518.
- Paradis-Deschênes P, Lapointe J, Joanisse DR, Billaut F. Similar recovery of maximal cycling performance after ischemic preconditioning, neuromuscular electrical stimulation or active recovery in endurance athlete. J Sports Sci Med. 2020;19(4):761-771.
- Page W, Swan R, Patterson SD. The effect of intermittent lower limb occlusion on recovery following exercise-induced muscle damage: A randomized controlled trial. J Sci Med Sport. 2017;20:729-733.
- Grønfeldt BM, Nielsen JL, Mieritz RM, Lund H, Aagaard P. Effect of blood-flow restricted vs heavy-load strength training on muscle strength: systematic review and meta-analysis. Scand J Med Sci Sports. 2020;30(5):837-848.
- Lixandrão ME, Ugrinowitsch C, Laurentino G, Libardi CA, Aihara AY, et al. Effets of exercise intensity and occlusion pressure after 12 weeks of training with blood-flow restriction. Eur J Appl Physiol. 2015;115(12):2471-80.
- Counts BR, Dankel SJ, Barnett BE, Kim D, Mouser JG, Allen KM, et al. The influence of relative blood flow restriction pressure on muscle activation and muscle adaptation. Muscle Nerve. 2016;53(3):438-45.