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Trends in Training: Blood Flow Restriction Training for Strength and Hypertrophy

Resistance training for strength and size is a long-established cornerstone of the fitness industry, harkening back centuries. Physical culture and bodybuilding laid the foundation for fitness as we know it today, and many of the same principles apply. However, science trumps tradition where sports and fitness are concerned, and major advances over the past few decades in our knowledge about human physiology have enabled athletes and fitness enthusiasts to grow bigger, faster, stronger and less prone to injury.

 

Training Smarter, Not Harder

Until recently, the formula for enhancing strength and hypertrophy has been calculated at about 65 percent of one-rep-max. For competitive bodybuilders, that can mean hours at the gym each day, cranking out multiple sets with long recovery breaks between. 

That is all well and good if you are already fit and have plenty of time on your hands. But for athletes recovering from injury, that approach is just not feasible. During rehabilitation, an injured athlete’s ultimate goal is to return to play. Yet an injured appendage cannot (and should not) be subjected to high training volumes during the healing process. 

Enter blood flow restriction, or BRF training, a promising new approach to increasing muscle strength and size at much lower training volumes.

A Quick Review of Basics

Overload is the underlying principle of all fitness training. When you challenge your body to perform at new levels, adaptations occur to help you meet future challenges. By manipulating muscle fiber recruitment, BFR training provides a way to increase muscle size and strength at much lower training volumes — as low as 20 to 30 percent of one-rep-max, as opposed to the traditional 65 percent. 

As an example, if you can press 500 pounds with your legs only one time, the traditional calculated training volume for hypertrophy would be 65 percent of 500, or about 325 pounds. With blood flow restriction training, you can achieve similar adaptations in muscle size and strength with about 100 to150 pounds.

As you will recall:

  • Your muscles are made up of two types of muscle fiber — Type I slow twitch and Type II fast twitch.
  • Type I muscle fibers rely heavily on oxygen to repeatedly contract, generate relatively low levels of force and are smaller than Type II fibers, but they can contract repeatedly without fatigue, as long as training intensity is low and oxygen is in ample supply.
  • Type II muscle fibers are larger and produce high amounts of force, but fatigue quickly, To contract, type II fibers rely on phosphocreatine (PCr) stored within the muscle cell, which the body produces in limited supply.

The idea behind blood flow restriction training is that by limiting available oxygen during weight training, Type I muscle fibers are deactivated, forcing Type II fibers to do the heavy lifting. 

But there’s more to it than that. Lactate, a precursor to growth hormone,  is a byproduct of Typpe II contraction that promotes muscle protein synthesis. After a BFR training session, growth hormone secretion can be as much as 170 percent higher than after a traditional training session.

Because BFR uses significantly less weight, damage to muscle fibers is limited, while protein synthesis is enhanced. By deactivating Type I fibers, gains in muscle strength and size can be achieved with much lower training loads.

How BFR Works

During BFR training, tight cuffs or bands are applied to your upper arm or upper leg, limiting blood flow during your exercise set. It is important to note that only those two sites are considered safe for applying blood flow restriction bands.  Applying them elsewhere can potentially damage nerves and other soft tissue.

BFR training can be used with almost any type of exercise.

  • A typical BFR training protocol is one set of 30 repetitions, followed by three sets of 15 repetitions, or 30/15/15/15, for a total of 75 reps. 
  • Perform reps slowly, with a 2 second count each for concentric and eccentric phases. 
  • Allow 30 seconds’ rest between sets.

BFR training bands can be purchased online. Some allow you to measure occlusion pressure precisely. Recommended occlusion for the lower body is 80 percent, and 50% for the upper body. For BFR straps that do not measure pressure, use a rating of discomfort scale of 6-8 out of 10 for the lower body, and 4-5 out of 10 for the upper body.

Stay Up to Speed with W.I.T.S.

Innovative advances in physiology and exercise science are being made every day, with no sign of slowing down any time soon. As a fitness professional, you cannot afford to stay out of the loop. Enhance your knowledge, keep up with the trends, and gain  valuable CECs with W.I.T.S. continuing education. Boost your credentials with an additional certification, like Youth Fitness or Older Adult. Get the CECs you need to renew your certs with our Health and Fitness series, and our monthly webinars. Stay current with all the latest trends in fitness by subscribing to the W.I.T.S. blog, and leave your competition in the dust.

Source: Nitzsche, N., et al. “Comparison of an Acute Resistance Training on the Lactate Concentration with and without Blood Flow Restriction at Different Loads.” (2018).

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