Blood Flow Restriction: Rehab & Fitness Applications

Blood Flow Restriction:  Rehab & Fitness Applications
by Coach ROBERT HAVILAND MS,BS PT,CSCS,CES

Blood Flow Restriction (BFR) training is an exercise technique that manipulates the body’s circulatory system, and when combined with exercise, produces rapid gains in strength and fitness using light-weights in a very short period of time.

BFR training induces an anabolic response through various pathways perhaps the most important of which is by preferentially targeting the large fast twitch muscle fibers.  Fast twitch fibers are the biggest muscle fibers and have the most potential for growth.  These fibers are recruited last during contractions and are mostly anaerobic (don’t use oxygen) whereas the smaller slow twitch fibers are recruited first during contractions and are aerobic (use oxygen).  Slow twitch fibers have a much smaller potential for growth compared to fast twitch fibers.  BFR training restricts blood flow to muscles, pre-fatiguing the slow twitch fibers and forcing the anaerobic fast twitch fibers to handle the load even at low intensities (2).  Metabolically, your muscle is getting a similar effect to lifting heavy loads but using much lighter weights.  Not only does restriction training preferentially activate fast twitch muscle fibers, it has been shown to cause a fiber type shift from slow to fast, thus increasing the potential for muscular growth and size (3)

Metabolic by-product accumulation is the primary mechanism by which occlusion training produces hypertrophy.  These metabolic by-products would normally be ‘washed out’ by normal blood flow, but occlusion allows them to accumulate near the muscle.  Lactate accumulation in particular seems to have an effect, presumably by increasing growth hormone (GH) concentrations (4-5).  In fact, one study found that BFR training caused a GH increase 290 times above baseline (4)!    This is a twofold greater increase in GH than what is produced by normal heavy resistance training (6).

BFR training has also been shown to increase muscle protein synthesis, mTOR signaling, and the expression of NOS-1 which has been shown to increase muscle growth through increased satellite cell activation (7-9).  Perhaps even more impressive, BFR training has been demonstrated to reduce myostatin concentrations (9 ). Myostatin is a significant inhibitor of muscle growth and is thought to limit the muscle potential of muscle gain.  To summarize,  blood – flow restriction training may be able to increase the overall potential of muscle gain through slow to fast fiber shifts and reductions in myostatin.

BFR isn’t a replacement for heavy training, but   very useful for people who can’t train heavy due to injury or tapering. However, restriction   provides several long- term benefits that regular heavy training doesn’t including slow to fast fiber transitions and a greater hormonal response.

The primary mechanisms by which blood flow restriction training stimulates growth include: metabolic accumulation which stimulates a subsequent increase in anabolic growth factors, fast-twitch fiber recruitment (FT), and increased protein synthesis through the mammalian target of rapamycin (mTOR) pathway. Increases in heat shock proteins (HSP), Nitric oxide synthase-1 (NOS-1), and decreased expression of Myostatin have also been observed.

Blood flow restriction training research thus far is hopeful with respect to safety results and outcomes. Individuals respond similarly to blood flow restriction training as to regular exercise.

HOW IT WORKS

Inflatable bands are worn around the upper portion of the arms and/or legs to safely slow the blood in the limb. BFR training modifies the blood flow to the limb during exercise to make the brain think the muscle is working hard. This triggers a robust, anabolic, hormonal release into the blood stream. The bands are inflated to individualized pressures prescribed by the BFR SYSTEM. Simple, low-load exercise produces profound muscle “burn” comparable to intense anaerobic training. This strong fatigue triggers a natural, robust, hormonal cascade, which in turn produces hypertrophy and strength gains on par with heavy exercise or traditional weight lifting. The hormones circulating in the blood stream benefit all areas of the body that were working, not just the restricted limb(s) creating a “Systemic Response.” The systemic response affects all working and healing tissue. Increased growth hormone levels promote improved energy levels and anti-aging, increased performance, and helps to maintain bone density. In other words, your whole- body benefits by this type of training. Benefits can be felt quickly in only a few sessions. It is safe and effective with fast setup and full body workout in less than 30 minutes. It reduces overall   stress on joints without sacrificing training effectiveness.

It is also effective in rehabilitation.   Maintain strength through injury recovery to mitigate atrophy and maintain fitness because absolute workloads are low or easy with little additional damage from the exercise. This allows for rapid recovery and improvement in fitness.

BFR training is a fitness phenomenon. A favorite among elite athletes and fitness enthusiasts who count on BFR training to enhance their performance levels and reach their sports fitness goals with gains in muscle strength, stamina, speed and agility. By using lower loads there is less wear and tear on the body and therefore BFR training is the premiere strength training tool for the athletic population.

References:
1)  Loenneke JP and Pujol TJ.  The Use of Occlusion Training to Produce Muscle Hypertrophy.  Strength & Conditioning Journal. 31(3): 77-84, June 2009.

2)   Takarada Y, Takazawa H, Sato Y, Takebayashi S, Tanaka Y, and Ishii N.  Effects of resistance exercise combined with moderate vascular occlusion on muscle function in humans. J Appl Physiol 88: 2097–2106, 2000.

3)  Kawada S and Ishii N.  Changes in skeletal muscle size, fiber-type composition and capillary supply after chronic venous occlusion in rats. Acta Physiol 192: 541–549, 2008.

4)  Takarada Y, Nakamura Y, Aruga S, Onda T,Miyazaki S, and Ishii N.  Rapid increase in plasma growth hormone after low-intensity resistance exercise with vascular occlusion. J Appl Physiol 88: 61–65, 2000.

5)  Takano H, Morita T, Iida H, Asada K, Kato M, Uno K, Hirose K, Matsumoto A, Takenaka K, Hirata Y, Eto F, Nagai R, Sato Y, and Nakaajima T. Hemodynamic and hormonal responses to a short-term low-intensity resistance exercise with the reduction of muscle blood flow.  Eur J Appl Physiol 95: 65–73, 2005.

6)  Kraemer W, Marchitelli L, Gordon S, Harman E, Dziados J, Mello R, Frykman P, McCurry D, and Fleck S.  Hormonal and growth factor responses to heavy resistance exercise protocols. J Appl Physiol 69: 1442

7)  Fujita S, Abe T, Drummond M, Cadenas J, Dreyer H, Sato Y, Volpi E, and Rasmussen B.  Blood flow restriction during low-intensity resistance exercise increases S6K1 phosphorylation and muscle protein synthesis. J Appl Physiol 103: 903–910, 2007.

8)  Anderson J.  A role for nitric oxide in muscle repair: nitric oxide-mediated activation of muscle satellite cells. Mol Biol Cell 11: 1859–1874, 2000.

9)  Kawada S and Ishii N.  Skeletal muscle hypertrophy after chronic restriction of venous blood flow in rats. Med Sci Sports Exerc 37: 1144–1150, 2005.