strength

Blood Flow Restriction (BFR) Training

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Occlusion-Training

What is it?

Blood flow restriction (BFR) is a training strategy involving the use of wraps or cuffs placed proximally around a limb; with the aim of maintaining arterial flow while occluding venous return during exercise (Scott et al. 2015). In layman’s terms this means that blood is flowing into the muscle; but none, or very little is getting out.

How is it performed?

A popular method is to use elasticated knee wraps and wrap them around the upper thighs or upper arms. A perceived wrap tightness of 7/10 will result in complete venous, but not arterial occlusion and has been used in a study by Lowery et al. (2014).

One must ensure the wraps are not too tight nor too lose. Loenneke et al. (2014) found that pressure appeared to increase muscle activation from 40-50% arterial occlusion but did not result in further increases at higher pressure. In other words, if they’re too tight
you will not elicit any benefits and you’ll increase risk of injury, if they are not tight enough blood easily leaves the muscle, eliminating the purpose of the wraps. Many strategies have been reported, however relatively light load resistant training using 20-30% 1RM is most common. Performing 4-6 sets to failure of exercises such as leg extensions, hamstring curls, squats, lunges, biceps curls, and triceps extensions.

Why use this technique?

Takarada et al (2002) did a study on a group of 17 male athletes and divided them into 3 groups – low intensity with occlusion (LIO); low intensity without occlusion (LI), and normal training.

The LIO group had both sides of their upper thighs trained with the proximal portions being compressed by a specially designed elastic belt. The subjects performed bilateral knee extensions for 4 sets at approximately 50% of their predetermined 1RM to failure, with 30 second rest intervals. Sessions lasted no longer than 10 minutes. The LI group then had to match the number of reps performed by the occlusion group. This was completed twice a week for 8 weeks, totalling 16 sessions.

This study aimed to measure several things including changes in muscle strength through measurement of isokinetic strength at preset angular velocities, and measurement of isometric torque at a knee angle of 80 degrees. They estimated changes in muscle endurance by having the subjects perform 50 repeated contractions of leg extensions and comparing the average value of peak torque during the last ten contractions compared to the initial ten contractions.

In addition, an MRI was used to retrieve cross-sectional images of the thigh in order to determine if an increase in strength was due to muscle hypertrophy or neuromotor adaptation. EMG signals were recorded from the vastus lateralis muscle as an indicator of muscle fibre recruitment during isometric torque exertion. Tests and image results were recorded prior to and after the 16 sessions.

The results of this study are undeniable as dramatic increases occurred within the LIO group in comparison to the LI and untrained control group. Percentage increases in strength after training were 14.3 (2.0)%, and 3.2 (2.3)% for the LIO and LI groups, respectively. Significant improvements in muscle endurance was seen in the LIO group only, which was believed to be caused by metabolic adaptations in the muscle fibres instead of an increased resistance to fatigue in the nervous system.

Both pre and post training MRI images were taken of the LIO group only. After the 8 weeks of vascular occlusion there was an approximate 15% increase of the cross-sectional area of the knee extensors. These results suggest that the increase in strength after occlusion training is due primarily to muscle hypertrophy.

Since hormones basically control everything, I want to quickly refer to a separate study previously conducted by Takarada et. al (2000). This study looked at growth hormone after low-intensity exercise with occlusion. The protocol was very similar to the one mentioned above, but used just 20% of the subjects 1RM.

The results of this study indicated that exercise with occlusion can provoke strong endocrine responses even at low intensities, as growth hormone increased 290 times as high as that before exercise. This is a significantly greater increase than that reported by Kraemer et al. (1990) for high-intensity resistant exercise with a short rest period (typical bodybuilding routine).

Conclusion

Blood flow restriction is a training strategy that can elicit major increases in muscle size and strength, as well as improvements in muscle endurance using just 20-50% 1RM. Major increases in growth hormone, peaking 15 minutes after the completion of low intensity resistance exercise with occlusion have been reported. This increase is even greater than that found after high-intensity resistance exercise without occlusion.

How I Use BFR

I recently employed this technique in my own training. Thus far I have completed 4 barbell back squat sessions using 35% of my 1RM, and 2 barbell front squat sessions using 30% 1RM. I performed 15-20 reps for 4-5 sets and keep my rest period under 1 minute. Since I do not have access to the special cuffs I have been using elasticated wraps and follow the suggested perceived wrap tightness of 7/10. Since the studies I have read kept the total occluded time within 10 minutes, I do as well; only removing the wraps after I have completed the exercise session.

It is difficult for me to measure if increases in muscular strength, size, and/or endurance is solely attributed to BFR as I train in weightlifting 3-4 times/ week and recently got back on my rollerblades since the weather has gotten more tolerable up in the North. However, I do plan on re-testing my 1RM back squat after a few more sessions, as prior to utilizing BFR my numbers were plateauing. Simply from the way my legs look and feel after these 6 sessions, coupled with the results of these studies, I am confident this will be the catalyst to any increases in my performance.

 

 

 

References

Scott, B. R., Loenneke, J. P., Slattery, K. M. & Dascombe, B. J. (2015). Blood flow restricted exercise for athletes: a review of the evidence. Journal of Science and Medicine in Sport.

Lowery, R. P., Joy, J. M., Loenneke, J. P., de Souza, E. O., Machado, M., Dudeck, J. E. & Wilson, J. M. (2014). Practical blood flow restriction training increases muscle hypertrophy during a periodized resistance training programme. Clinical Physiology and Functional Imaging, 34(4), 317-21.

Loenneke, J. P., Kim, D., Fahs, C. A., Thiebaud, R. S., Abe, T., Larson, R. D., Bemben, D. A. & Bemben, M. G. (2014a). Effects of exercise with and without different degrees of blood flow restriction on torque and muscle activation. Muscle and Nerve.

Takarada, Y., Sato, Y., Ishii, N., (2002). Effects of resistance exercise combined with vascular occlusion on muscle function in athletes. European Journal of Applied Physiology.

Takarada, Y., Nakamura, Y., Aruga, S., Onda, T., Miyazaki, S., Ishii, N. (2000). Rapid increase in plasma growth hormone after low-intensity resistance exercise with vascular occlusion. Journal of Applied Physiology.

Kraemer, W. J., L. Marchitelli, S. E. Gordon, E. Harman, J. E. Dziados, R. Mello, P. Frykman, D. McCurry, S. J. Fleck. (1990). Hormonal and growth factor response to heavy resistance exercise protocols. Journal of Applied Physiology.

Weightlifting

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September 1st, 2015 I made the move from Brampton to North Bay, Ontario. I came in light of new experiences and the opportunity to learn how to Olympic style weight lift from one of the best coaches, Larry Sheppard.

My desire to get in shape started when I was 16 years old, and now at 28; I have learned so much through education, personal successes, and failures. However, just when I thought I had a good grasp on everything; my style of training has been completely flipped in pursuit of becoming an athlete.

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For as long as I can remember I worked out to look good. Vanity and lack of self esteem pushed me towards the commercial facilities where mirrors line every wall, and platforms are non existent. I’ve worked out in gyms that don’t allow chalk, and have had employees tell me I can’t drop the weights as I was performing heavy deadlifts.

I dipped my toes in the physique competitions – but in all honestly they were super amateur. It’s something I am proud of in the sense it took hard work and courage; but at the same time I roll my eyes because it just wasn’t me.

I wish I had known someone in the powerlifting or weightlifting community 10 years ago; but would-a-should-a-could-a; this is where I am at now and thats what matters. I began learning the snatch and clean & jerk in early September 2015.

What is the Snatch?

Snatch+Phases+Trajectory-lowres

The Snatch is the first of the two Olympic lifts to be contested, followed by the clean & jerk. The aim is the lift a loaded bar from the floor to overhead, in one smooth, continuous motion.

The athlete begins by setting themselves up so that the bar is directly over their metatarsals with their feet hip width apart; toes turned out slightly. A wide “hook grip” is used on the bar (fingers on top of thumbs), and the arms straight with the shoulders directly over the bar, or slightly in front of it. The thighs should be almost parallel to the floor (depending on femur length), and the back remains straight and tight with extension in the thoracic vertebrae. The chest should be open and head titled back.

“Lift off” begins the moment the bar is separated from the floor as the athlete then moves into the “first pull.” During this phase the lifter begins to extend their knees and moves their hips upward while keeping a constant back angle relative to the floor. Centre of gravity shifts towards the heels as the lifter pulls the bar close to their body. The bar begins to accelerate at the end of this phase as they “transition” to position themselves appropriately for the second pull. During this transition is where you’ll often see the “double-knee” bend.

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$50,000 Eleiko platform from the Pan Am games

The “second pull” is an explosive movement that is executed through the extension of the hips, knees, and ankles (triple extension); followed by a strong elevation of the shoulders (shrug). This is where the bar will “brush” the hips and feet leave the ground to quickly move into the squat position. The “turnover” phase occurs as the lifter begins to pull themselves under the bar, and the “catch phase” occurs the moment the lifters feet have landed on the platform, catching the bar overhead with arms locked out. It is finished only when the lifter shows control of the bar by standing up and bringing the feet together.

What is the clean & jerk?

The clean & jerk is the second lift to be contested and is comprised of two stages which also has the athlete lift the bar from the floor to an overhead position.

They begin by setting their feet under their hips and by grabbing the bar just outside their legs using a “hook grip.” The bar is lifted to the top of the knees where the athlete then performs the “triple extension” through explosive extension of the hips, knees, and ankles; followed by a big shrug. The aim here is to get the bar as high as possible before dropping into the squat and receiving the bar in the “racked” position (bar sits in front of the neck resting on the anterior deltoids). The lifter then stands back up and readjusts their grip width in preparation for the jerk.

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The jerk begins where the clean finishes; with the bar across the shoulders and the back vertical. The lifter dips just a few inches by flexing the knees; then through explosive extension of the knees the barbell is propelled upwards off the shoulders. The athlete pushes the bar with their arms and quickly drops under by splitting their feet in a lunge type fashion (one forward and one back). The bar is received overhead with the arms straight, and once stable; the lifter recovers from the split position by bringing their feet back together.

Ofcouse these explanations may be missing some aspects, but you get a good idea of what I have been up to over the past 8 months. I have competed in 3 competitions thus far and took 3rd place in my weight class in my last competiton on April 9, 2015. I still have a long ways to go before I am even close to competing on a more serious level (these girls are strong!!!), but I am just happy to have found something new and exciting. It feels great to be more concerned over how I perform rather than how I look.

Most importantly, I have been working hard to learn how to coach these lifts. I have engulfed myself in everything weightlifting and succeeded passing my level one weightlifting certification with the NCCP. I will have a second diploma in strength and sports condidtioning in a couple weeks time and I hope to find work in the health promotion and coaching fields.