What is blood flow restriction training? In fact, this training method is exactly what it sounds like: restricting blood flow to the muscles during exercise. This is usually done with special equipment such as blood flow restriction (BFR) cuffs.
What has caught people’s attention is its claimed benefits, with claims that BFR can stimulate impressive muscle growth and strength gains through lower-impact resistance training.
It has also been suggested that BFR can be used during low-intensity aerobic exercise, such as one of the best treadmills for walking. (will open in a new tab) – to prevent atrophy or loss of muscle mass in debilitated people such as the elderly and people with injuries.
To separate fact from fiction, we spoke with Jeremy Lönnecke, an associate professor of exercise at the University of Mississippi and an authority on blood flow restriction training.
Jeremy Lönnecke is the director of the Kevser Ermin Applied Physiology Laboratory at the University of Mississippi, and his research team focuses on skeletal muscle adaptation to exercise with and without blood flow restriction. He is a Fellow of the American College of Sports Medicine and a Fellow of the American Physiological Society.
What is blood flow restriction training?
As stated above, BFR involves restricting blood flow to the muscle that is currently working. Loenneke offers this summary. “Blood restriction training involves applying a cuff or bandage to the limb being treated (such as the upper leg or upper arm) to partially restrict blood flow to that limb.
“This restriction is combined with low-impact resistance exercise or low-intensity aerobic exercise. (will open in a new tab) to get benefits similar to those of high-impact or higher-intensity exercise.”
For example, BFR can be used with bicep curls. In this exercise, you place and tighten the cuff around the proximal arm (closest to the body) to restrict blood flow to the working muscle (biceps). Because of this, Lönnecke says, you can lift lighter weights while experiencing the same hypertrophy. (will open in a new tab) and the strength benefits of training with heavier loads.
How blood flow restriction training works
How blood flow restriction increases muscle size isn’t entirely known, Lönnecke says, but it’s likely similar to traditional weight training.
“In other words, when a muscle contracts, that contraction initiates a signal that turns on growth-promoting pathways (like mTORC1) in activated muscle fibers. As the exercises become more difficult, more fibers are activated.
“The application of blood flow restriction causes the muscles to work harder than normal, resulting in a higher level of muscle activation. This means that more and more fibers are being signaled to grow, even if the weight being lifted is very light (20-30g). % of maximum strength).
What equipment is needed?
A cuff or bandage is required for training with blood flow restriction. And, with the popularity of the practice growing, many of these products are available commercially—in stores and online. These cuffs are available in two basic styles: inflatable like B Strong cuffs. (will open in a new tab) below and practical.
“There are a number of commercial options for those interested in applying blood flow restriction,” says Lönnecke. “The main components include a cuff and a cuff inflation device.
“Many commercial devices available today also allow you to set individual limb pressure, i.e. pressure that takes into account the cuff being used and the size of the limb to which that cuff is applied (e.g. cuffing at 40% of the pressure needed to completely cut off blood flow).
“Another method is to practically restrict blood flow with an elastic bandage or cuff. This method is called “practical” because elastic bandages are easy to find and inexpensive. The disadvantage of this method is that it does not have a device to regulate the pressure, so it is impossible to know how much the restriction is being applied.”
What are the benefits
At first glance, the benefits of blood flow restriction may seem too good to be true: namely, they promote hypertrophy and increased strength when lifting light weights, which reduces the risk of injury for the lifter and allows people with compromised health to train more efficiently. However, there is literature supporting these claims.
“Most of the work [studying BFR] focused on changing muscle size and strength,” Lönnecke says. “Blood restriction combined with low-impact resistance training increases muscle size and strength.
“The change in muscle size is similar to the change in weight when doing high-impact exercise (70% of the maximum weight a person can lift). However, the change in maximum strength is often less—strength still increases, but not to the same extent.”
In a 2010 study published in the journal Clinical Physiology and Functional Imaging, 10 young men were asked to perform four sets of bench presses for a total of 75 reps with 30% of the maximum weight they could lift in one rep. They did this twice a day, six days a week, for two weeks, with one group using elastic cuffs placed proximally on both arms for BFR, and the rest of the subjects doing the exercise without cuffs.
After two weeks, the BFR group demonstrated a 6% increase in maximum bench press, an 8% increase in tricep muscle thickness, and a 16% increase in pectoralis major (the largest pectoral muscle) in thickness.
In contrast, in the control group, the 1-rep maximum in the bench press fell by 2%, while the thickness of the triceps and pectoralis major muscles remained almost unchanged (-1% and 2%, respectively).
In part, this may be due to the ability of BFR to act on the endocrine system. A 2016 study published in the European Journal of Applied Physiology. (will open in a new tab) found that four weeks of low-intensity resistance training with blood flow restriction resulted in a significant increase in growth hormone levels.
Being able to get similar results from resistance training and other forms of exercise while using lower loads and, as a result, less stress on the body can be beneficial for individuals or groups who cannot participate in more intense activities, Lönnecke says.
“There are certain groups of people who can improve muscle size and strength with slow walking or cycling with blood flow restriction, but the biggest changes occur when blood flow restriction is combined with resistance exercise.
“Some work suggests that the application of blood flow restriction alone may slow the loss of muscle size and strength during bed rest. However, the data for this is very limited.”
Who should do it
It may not be a common practice among regular athletes, but Lönnecke says blood flow restriction is something that can be used by regular gym goers looking to increase their strength and muscle mass. However, he advises including it in your training program, rather than adding it to the end of an already full training schedule.
“[Gym-goers] may use it as part of their regular training program, or they may use it when they get injured or want to add variety to their workouts,” Lönnecke says. “Some people like to turn it on towards the end of a workout, after they’ve completed some of their more traditional workouts.
“It can be effective, but it’s important to understand that muscles can only respond to a specific workout. If you’ve already done multiple sets of multiple exercises for a particular muscle group, it’s unlikely that adding another blood flow restriction exercise will add anything extra.”
Is blood flow restriction training dangerous?
While all exercise comes with risks, Lönnecke says many of the concerns about BFR are unfounded. However, more research is needed.
“Two common concerns are the risk of muscle damage and blood clots. The available literature suggests that adding blood flow restriction to exercise does not appear to increase the risk of either. This, of course, assumes that the stimulus is being used appropriately.”
The existing literature supports this. A 2021 systematic review of research on this subject published in the International Journal of Sports Physiotherapy. (will open in a new tab), states: “The biggest benefit of BFR appears to be its ability to safely increase exercise intensity in healthy individuals and those with underlying medical conditions. However, more research is needed before fully determining the long-term systemic effects of BFR.”