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Blood Flow Restriction Basics

You’ve probably heard of dry needling, but have you heard of blood flow restriction? Most have not as it is relatively new and only being utilized by a small number of physical therapists. However, at Resilience RX, we’re all about being on the cutting edge of research to give you the best outcomes. Because of that, we’ve done a deep dive into blood flow restriction and are excited to use it to help our clients get from where they are to where they want to be. Without any further adieu, let’s dive into what exactly blood flow restriction is and who can benefit from it.

What exactly is Blood Flow Restriction?

Blood flow restriction, or BFR for short, is a method of strengthening and improving endurance by restricting blood flow to muscles while doing light physical activity. BFR gets the same strength and endurance results as lifting heavy weights or doing prolonged aerobic exercise like running or biking.

BFR can induce these changes with light activity because restricting blood flow creates an environment where oxygen does not exist. The lack of oxygen in BFR forces the body to utilize different methods to produce energy that are normally reserved for the end-stages of exercise when exhaustion is reached. Exercise that is done near exhaustion is exercise that is the most effective on improving strength and endurance. Thus, because BFR can bring a muscle close to exhaustion, it can improve strength and endurance to the same extent that heavy lifting and aerobic exercise can.

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The Nerdy Details

If you’re not interested in how blood flow restriction works, but simply want to know what it works for, skip down to the bolded sentence at the bottom of this section to get a two second overview. If you enjoy nerding out or want all the info, keep reading.

Energy Sources for Exercise

Exercise utilizes three main energy systems – aerobic metabolism, anaerobic glycolysis, and creatine phosphate. Aerobic metabolism utilizes oxygen as an energy source. This is the energy system we utilize the large majority of the time.

However, when exercise starts to become more intense, our body starts to utilize the anaerobic glycolysis system. This produces lactate and hydrogen ions, which creates an acidic environment. The acidic environment is the “burn” feeling you get when you’re exercising and things start to get uncomfortable.

Creatine phosphate is when creatine and ATP combine to produce ADP. This is the system that gets boosted with creatine supplementation. It’s used for 45 seconds at most and is used in quick, powerful activities like a high jump or Olympic lift.

How Blood Flow Restriction Manipulates Energy Sources

With BFR, oxygen is occluded. Because of this, the body is forced to utilize anaerobic glycolysis. During anaerobic glycolysis, lactate accumulates. The accumulation of lactate causes an increased growth hormone release. Growth hormone is then responsible for activating muscle stem cells (myogenic stem cells). These partially differentiated stem cells are ultimately responsible for muscle growth via muscle protein synthesis.

Other Hormonal Changes

However, growth hormone isn’t the only hormone that is released with BFR. IGF-1 (insulin-like growth factor-1) and VEGF (vascular endothelial growth factor) are both released in large quantities. Myostatin, which plays a role in limiting muscle growth, is also suppressed with BFR. The magnitude of these changes with BFR is the same as with lifting heavy objects, making BFR a viable option for when heavy lifting cannot be performed. Essentially, BFR is a fast-track to utilizing energy systems that create a large hormonal response, thus creating muscle changes with lower loads than normal exercise.

What Blood Flow Restriction is Used For

Now that we’ve established that BFR is grounded in science, let’s get to the practical part – what it works for. BFR can be used for injuries and performance. We’ll be writing blog posts that explain this in more detail (and plan on linking them here later on), but for now, here’s a quick overview of what research says it is good for.

Recovery From These Surgeries

  • ACL reconstruction
  • Meniscus repair
  • Muscle repair (Achilles, rotator cuff, quadriceps, hamstring, etc.)
  • Joint replacement
  • Cartilage surgeries

Recovery From These Injuries

  • Tendinitis, tendinosis, tendinopathy
  • Arthritis
  • Decreasing Pain

Improving Performance

  • Increasing time to exhaustion during athletic performance
  • Preserving strength when training volume/load needs to be decreased
  • Volume/workload management before competitions
  • Decreasing muscle soreness
  • Speeding up recovery after a strenuous athletic event

What to Expect with Blood Flow Restriction

We believe it is important clients know what to expect before treatment occurs to reduce uncertainty associated with experiencing something new. So, when receiving BFR, here’s what to expect.

The Set-Up

We start by placing a cuff on your leg or arm. This cuff is pushed all the way up to your armpit or inner thigh and then inflated while you are lying still on your back. The inflated cuff feels very similar to when your blood pressure is being taken. The purpose of this step is to measure an individualized limb occlusion pressure, or the amount of pressure needed to fully block blood flow.

The cuff is then deflated and reinflated to where a percentage of blood flow is blocked. This percentage is chosen based on many factors including whether it’s your arm or leg, the task at hand, injury status, and more.

BFR In Action

While the cuff is reinflated, you’ll be asked to complete one exercise. Current best evidence shows that a protocol of 30 reps, 30” rest, 15 reps, 30” rest, 15 reps, 30” rest, 15 reps is best. The cuff remains inflated during this entire time and this entire process takes about 6-8 minutes.

Towards the end of the first set of 30 repetitions, most individuals start to feel a muscle burn similar to exercise. In the subsequent sets of 15 repetitions, despite using a light weight, the weight becomes very hard to move. It feels like you’re lifting heavy weights, but you’re not. You’re lifting a weight that is anywhere between 20-30% of the maximum amount of weight you can lift for that particular movement.

The Aftermath

After all reps are completed, the cuff is deflated and removed. The above sequence may be repeated for other muscles or only one muscle may be treated. It depends upon what is best for the individual at hand. Afterwards, most experience a fatigued feeling like they just worked out. Some individuals have muscle soreness the day after, some do not.

Safety of Blood Flow Restriction

We would be remiss if we wrapped this article up and didn’t discuss safety. In general, blood flow restriction is an incredibly safe option for recovering from an injury or maintaining wellness. Here’s a little breakdown of different concerns that individuals tend to have about BFR.

Risk for Clotting

With blood flow restriction, there is no increased risk from clotting. Risks from clotting come from genetics, history, and lack of movement. The most important factor of those three contributors is a lack of movement. The overwhelming majority of clots come after an individual has a period of time where they don’t get up and move around.

Furthermore, extensive research has been done into this topic. All BFR research shows no increase in markers that indicate clotting (D-dimer, CRP, fibrinogen) and it actually shows an increase in tPA. tPA is a protein that decreases clotting risk. Additional research has also shown that acute bouts of restricting blood flow actually protect against clotting in the long term.

Stress on the Heart

Blood flow restriction significantly alters blood pressure and heart rate, which is something those that have vascular problems should be aware of. However, the changes in blood pressure and heart rate are significantly greater with exercise than they are with BFR. This is because BFR is done at low loads compared to exercise. It is more stressful on the local muscle area than it is on the vascular system as a whole. A good way to summarize this is that if you can tolerate exercise, you can tolerate blood flow restriction.

Muscle Damage

Anytime there is pressure on any specific area of the body, a risk for damage occurs. This risk is minimized in blood flow restriction by using a wider cuff, which limits the amount of pressure needed on a specific area. There is also risk for muscle damage due to a lack of oxygen. However, the cuff only stays inflated for 6-8 minutes at a time, which is much less than the amount of time needed to cause muscle damage.

Interestingly, the risk for muscle damage is higher for those participating in research studies due to the higher frequency of performing BFR than it is for those receiving treatment in a clinic. Muscle damage has only been documented in three cases and all those cases had other significant contributing factors. Essentially, if you’re applying BFR correctly, there is no risk for muscle damage.

Wrapping Things Up

Blood flow restriction is effective at increasing strength and endurance because oxygen restriction bypasses the normal energy systems and sends you straight to muscle exhaustion. Because of this, it often feels like you just did a workout when you’re done with BFR.

Blood flow restriction is safe and incredibly effective at accelerating post-surgical recovery, rehabilitating injuries, and improving performance. We believe it’s going to become a treatment option that grows in popularity over the next decade due to its effectiveness. If you have questions as to whether or not you could benefit from BFR, reach out. We’d love to answer them!

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