Blood Flow Restriction during Low-Intensity Resistance Exercise Increases S6K1 Phosphorylation and Muscle Protein Synthesis.

[Fahsy]

http://jap.physiology.org/cgi/reprint/00195.2007v1

J Appl Physiol. 2007 Jun 14

Blood Flow Restriction during Low-Intensity Resistance Exercise Increases S6K1 Phosphorylation and Muscle Protein Synthesis.

Fujita S, Abe T, Drummond MJ, Cadenas JG, Dreyer HC, Sato Y, Volpi E, Rasmussen BB.

Internal Medicine, University of Texas Medical Branch, Galveston, Texas, United States; Human and Engineered Environment, Graduate School of Frontier Sciences, University of Tokyo, Tokyo, Texas, Japan.

Low-intensity resistance exercise training combined with blood flow restriction (REFR) increases muscle size and strength as much as conventional resistance exercise with high-loads. However, the cellular mechanism(s) underlying the hypertrophy and strength gains induced by REFR are unknown. We have recently shown that the mTOR signaling pathway is involved in the increase in muscle protein synthesis after an acute bout of high-intensity resistance exercise in humans. Therefore, we hypothesized that an acute bout of REFR would enhance mTOR signaling and stimulate muscle protein synthesis (MPS). We measured MPS and phosphorylation status of mTOR-associated signaling proteins in 6 young male subjects. Subjects were studied once during blood flow restriction (REFR, bilateral leg extension exercise at 20% of 1-RM while a pressure cuff was placed on the proximal end of both thighs and inflated at 200mmHg) and a second time using the same exercise protocol but without the pressure cuff (CTRL). MPS in the vastus lateralis muscle was measured by using stable isotope techniques and the phosphorylation status of signaling proteins were determined by immunoblotting. Blood lactate, cortisol, and growth hormone were higher following REFR as compared to CTRL (P<0.05). S6K1 phosphorylation, a downstream target of mTOR, increased concurrently with a decreased eEF2 phosphorylation and a 46% increase in MPS following REFR (P<0.05). MPS and S6K1 phosphorylation were unchanged in the CTRL group post-exercise. We conclude that the activation of the mTOR signaling pathway appears to be an important cellular mechanism which may help explain the enhanced muscle protein synthesis during REFR. Key words: mTOR , ischemia, hypertrophy, protein metabolism, post-exercise recovery.


This is another interesting paper showing the mechanism behind why occlusion can stimulate hypertrophy. A stronger paper compared to the other paper I posted from EJAP.

[Venom]

Whats really interesting to me, is that a lot of studies on protein synthesis attribute the increase in protein synthesis to enhanced blood flow (and particularly extracellular amino acid delivery). And off course, bodybuilders have always been huge on training to the "pump."

So would this support static contraction techniques as well?

[Fahsy]

That's a great point. It is possible that the reactive hyperemia that occurs after occulsion allows for greater neutrient delivery. It would be intersting to perform a study involving a glucose challenge test and occulusion to see if the occulusion improves glucose uptake.

Not sure about the static contraction technique- would you say blood flow is restricted during a staic contraction?

[Venom]

Yup, I would definitely say it is.

[Fahsy]

Ok. I don't do statics very often but when I did them I never really felt like they caused occulusion.

[Streetman]

Sooo...how can we put this into real world practice? The way I read this article, as silly as this sounds, if I tie off my biceps like a introvenious drug user, and then do curls, I'm going to induce hytropophy to a greater extent. Is this correct?

I'm going look like a moron in the weight room. Oh well.

[Fahsy]

Yeah, that's basically how it would be applied. And who cares what people think, you're at the gym to get big.

[airborneninja]

And to fight the myth that the squat rack is for pushups.

[MartinofSweden]

I tried this traing method a while back, and even though the rubber bands I used around my upper arms didn´t remotely cause a complete occlusion, the pain I experienced both during the sets and in between really made working out a challenge. I´m not sure you can get a similar experience if you train isometrically, even though muscle contraction causes an occlusion, but by working dynamically without losing tension at the end and/or beginning of the motion you´ll probably get close. The most challenging part about training with external occlusion would still be the time between sets. The pump you get is almost unbearable, because blood is forced into the body part that´s being trained, but it can´t escape back, even after you finished a set. I hope I don´t scare anyone off from trying this, just want you to be prepared for pain. I personally haven´t abandoned this method yet though, even though I´ll need to convince myself pretty hard that it´s going to be benefitial before I pursue it again. I´m still trying to figure out what to use instead of the thin rubber bands I used. I used like 12-15 small ones on each arm but it felt like the partial pressure to my skin was a bit to high - almost like it was going to break my skin. So I dont think I wanna do that again. If any of you guys has any ideas just let me know.

[Venom]

[ QUOTE ]
Whats really interesting to me, is that a lot of studies on protein synthesis attribute the increase in protein synthesis to enhanced blood flow (and particularly extracellular amino acid delivery). And off course, bodybuilders have always been huge on training to the "pump."

[/ QUOTE ]

After doing this a few times, like martin stated, I noticed the pump is larger. It appears that blood just gets trapped their and can't escape. So its more like a continual pump, actually supporting the bodybuilding notion of inducing big pumps for growth.

Martin

Layne Norton said he wrapped two size "small" weight belts around his legs for thighs. I used an LP support wrap. I also used a rope from my robe. I can't imagine using rubber bands. That would kill the skin!

[MartinofSweden]

Yeah I know, it does kill the skin, but I didn´t imagine something non-elastic would work well. From the studies I´ve seen they apply complete occlusion (legs somewhere around 140 mm/hg). Wouldn´t applying that kind of pressure with a rope, a weight belt or similar cause severe pain to working structures (tendons, muscles)? I´m not sure I could take that additional pain, the ishemia alone is almost more than I can take. And if it´s on too loosely maybe it doesn´t cause the desired effekt (too low pressure) when muscles are relaxed and not working. Maybe it´s not necessary to complete occlude either, but the response should be bigger if you do, right? Well, maybe it´s just me being a cry baby. Perhaps I should develop a special gadget for this purpose /forum/images/graemlins/cool.gif

[Venom]

The LP support / compression wrap is very comfortable, and does not hurt the skin at all. I wrapped it as tight as I could. I had to loosen it a bit after a couple sets, because my calves were expanding due to the pump. I did it for calves yesterday, and it killed. I basically tie it as tight as you can without feeling uncomfortable pain.

[MartinofSweden]

Sounds good, I´ll give it a try. I´ll look for one to use around my upper arm thats not too wide, although it might become difficult to find one long enough to reach around my freaky biceps. /forum/images/graemlins/grin.gif Gabe, you write you use this method when training calves, which made me thinking, perhaps one could instead (or also) use vascular occlusion during morning walks (or any cardio). Think of all the people with claudicatio intermittens due to arterial insufficiency in the lower legs. They sometimes have calves that would impress even the most dedicated bodybuilder. There is a study i read a little while back on young men which found walking with v.o. to be stimuli enough to induce muscule hypertrophy. Check it out if you like, here is the abstract:

J Appl Physiol. 2006 May;100(5):1460-6. Epub 2005 Dec 8.

Previous studies have shown that low-intensity resistance training with restricted muscular venous blood flow (Kaatsu) causes muscle hypertrophy and strength gain. To investigate the effects of daily physical activity combined with Kaatsu, we examined the acute and chronic effects of walk training with and without Kaatsu on MRI-measured muscle size and maximum dynamic (one repetition maximum) and isometric strength, along with blood hormonal parameters. Nine men performed Kaatsu-walk training, and nine men performed walk training alone (control-walk). Training was conducted two times a day, 6 days/wk, for 3 wk using five sets of 2-min bouts (treadmill speed at 50 m/min), with a 1-min rest between bouts. Mean oxygen uptake during Kaatsu-walk and control-walk exercise was 19.5 (SD 3.6) and 17.2 % (SD 3.1) of treadmill-determined maximum oxygen uptake, respectively. Serum growth hormone was elevated (P < 0.01) after acute Kaatsu-walk exercise but not in control-walk exercise. MRI-measured thigh muscle cross-sectional area and muscle volume increased by 4-7%, and one repetition maximum and maximum isometric strength increased by 8-10% in the Kaatsu-walk group. There was no change in muscle size and dynamic and isometric strength in the control-walk group. Indicators of muscle damage (creatine kinase and myoglobin) and resting anabolic hormones did not change in both groups. The results suggest that the combination of leg muscle blood flow restriction with slow-walk training induces muscle hypertrophy and strength gain, despite the minimal level of exercise intensity. Kaatsu-walk training may be a potentially useful method for promoting muscle hypertrophy, covering a wide range of the population, including the frail and elderly.

[Venom]

I think that's a good idea. Layne told me that an experiment had elderly people induced occlusion during their regular everyday lives (forget the bodypart) and protein synthesis was improved!

[MartinofSweden]

This topic has been off for a while so I thought I´d give it an update. Three very interesting studies have been published recently. One of them shows that it´s not necessary to achieve complete occlusion to get positive effects. That´s good news for wimps like me. Another study shows that the weight needs to be low and reps high to achieve desired effect. Heavy resistance training without occlusion is more effective than it is with occlusion. And the third and most interesting shows that there is a cross transfer training effect with vascular occlusion, but the non-occluded body part needs to be stimulated with strength training in order to claim the benefit of the subsequent workout of another bodypart with occlution. That sounded really confusing, I know, but check out these abstracts and read for yourselves:

1.Effects of Strength Training and Vascular Occlusion.
Laurentino G, Ugrinowitsch C, Aihara AY, Fernandes AR, Parcell AC, Ricard M, Tricoli V.
Department of Physical Education, Paulista University, Sao Paulo, Brazil.

The purpose of our study was to determine if vascular occlusion produced an additive effect on muscle hypertrophy and strength performance with high strength training loads. Sixteen physically active men were divided into two groups: high-intensity (HI = 6 RM) and moderate-intensity training (MI = 12 RM). An occlusion cuff was attached to the proximal end of the right thigh, so that blood flow was reduced during the exercise. The left leg served as a control, thus was trained without vascular occlusion. Knee extension 1 RM and quadriceps cross-sectional area (MRI) were evaluated pre- and post-8 weeks of training. We only found a main time effect for both strength gains and quadriceps hypertrophy (p < 0.001). Therefore, we conclude that vascular occlusion in combination with high-intensity strength training does not augment muscle strength or hypertrophy when compared to high-intensity strength training alone.

2.Effect of resistance exercise training combined with relatively low vascular occlusion.
Sumide T, Sakuraba K, Sawaki K, Ohmura H, Tamura Y.
Department of Sports Medicine, School of Health and Sports Science, Juntendo University, Japan.

Previous studies have demonstrated that a low-intensity resistance exercise, combined with vascular occlusion, results in a marked increase in muscular size and strength. We investigated the optimal pressure for reduction of muscle blood flow with resistance exercise to increase the muscular strength and endurance. Twenty-one subjects were randomly divided into four groups by the different application of vascular occlusion pressure at the proximal of thigh: without any pressure (0-pressure group), with a pressure of 50mmHg (50-pressure group), with a pressure of 150mmHg (150-pressure group), and with a pressure of 250mmHg (250-pressure group). The isokinetic muscle strength at angular velocities of 60 and 180 degrees /s, total muscle work, and the cross-sectional knee extensor muscle area were assessed before and after exercise. Exercise was performed three times a week over an 8-week period at an intensity of approximately 20% of one-repetition maximum for straight leg raising and hip joint adduction and maximum force for abduction training. A significant increase in strength at 180 degrees /s was noted after exercise in all subjects who exercised under vascular occlusion. Total muscle work increased significantly in the 50- and 150-pressure groups (P<0.05, P<0.01, respectively). There was no significant increase in cross-sectional knee extensor muscle area in any groups. In conclusion, resistance exercise with relatively low vascular occlusion pressure is potentially useful to increase muscle strength and endurance without discomfort.

3.Cross-Transfer Effects of Resistance Training with Blood Flow Restriction.

BASIC SCIENCES

Medicine & Science in Sports & Exercise. 40(2):258-263, February 2008.
MADARAME, HARUHIKO 1; NEYA, MITSUO 1; OCHI, EISUKE 2; NAKAZATO, KOICHI 2; SATO, YOSHIAKI 3; ISHII, NAOKATA 1
Abstract:
Purpose: This study investigated whether muscle hypertrophy-promoting effects are cross-transferred in resistance training with blood flow restriction, which has been shown to evoke strong endocrine activation.

Methods: Fifteen untrained men were randomly assigned into the occlusive training group (OCC, N = 8) and the normal training group (NOR, N = 7). Both groups performed the same unilateral arm exercise (arm curl) at 50% of one-repetition maximum (1RM) without occlusion (three sets, 10 repetitions). Either the dominant or nondominant arm was randomly chosen to be trained (OCC-T, NOR-T) or to serve as a control (OCC-C, NOR-C). After the arm exercise, OCC performed leg exercise with blood flow restriction (30% of 1RM, three sets, 15-30 repetitions), whereas NOR performed the same leg exercise without occlusion. The training session was performed twice a week for 10 wk. In a separate set of experiments, acute changes in blood hormone concentrations were measured after the same leg exercises with (N = 5) and without (N = 5) occlusion.

Results: Cross-sectional area (CSA) and isometric torque of elbow flexor muscles increased significantly in OCC-T, whereas no significant changes were observed in OCC-C, NOR-T, and NOR-C. CSA and isometric torque of thigh muscles increased significantly in OCC, whereas no significant changes were observed in NOR. Noradrenaline concentration showed a significantly larger increase after leg exercise with occlusion than after exercises without occlusion, though growth hormone and testosterone concentrations did not show significant differences between these two types of exercises.

Conclusion: The results indicate that low-intensity resistance training increases muscular size and strength when combined with resistance exercise with blood flow restriction for other muscle groups. It was suggested that any circulating factor(s) was involved in this remote effect of exercise on muscular size.

[RawIron]

This isn't dangerous?

[MartinofSweden]

It shouldn´t be. Of course it raises blood pressure during the exercise bout. But so does regular strength traning. Unless you´re suffering from heart disease you should be absolutely fine. If on the other hand you have a heart problem, you should avoid this type of training. In such case traditional, dynamic strength training might be more beneficial/less harmful.

[klosey]

interesting old post lets bring it back to life!`

[klosey]

Just noticed this, Jeremy you may of been beaten to the punch with occlusion :p

[Achillesreborn]

Just out of curiosity, I thought that the "pump" had nothing to do with size and strength gains... isn't it just glycogen stores? Don't get me wrong, I love the pump, I was just under the impression it had nothing to do with progression in weight training and bodybuilding.

[klosey]

Just out of curiosity, I thought that the "pump" had nothing to do with size and strength gains... isn't it just glycogen stores? Don't get me wrong, I love the pump, I was just under the impression it had nothing to do with progression in weight training and bodybuilding.

the pump in general doesnt but affter occlussion the pump is due to full blood flow being restored and nutrients being pulled into the muscle at a faster rate, It technically allows you to build muscle without destroying it first

[Achillesreborn]

the pump in general doesnt but affter occlussion the pump is due to full blood flow being restored and nutrients being pulled into the muscle at a faster rate, It technically allows you to build muscle without destroying it first


Very interesting, I may have to try this out some time!

[klosey]

Very interesting, I may have to try this out some time!

i was 7 days in to a 30 occlusion experiment i decided to do but had to stop due to being put on meds but i'll be good to go next month

[MslAdct83]

One thing to remember is that when a muscle is fully contracted blood flow is restricted. You can achieve close to the same effect by using extended static contractions. It works wonders. Use an isolation exercise and do a static contraction with a weight that will cause failure at more than 30s. Longer is preferred as it will create a better effect. The resulting pump afterward is VERY intense!

[Venom]

Yeah, I do statics for chest for the occlusion effect...since it is impossible to use wraps for that muscle. But you have to do heavy statics - above 65% 1 RM.

[MslAdct83]

yeah that sounds about right. Usually a weight that I can handle for about 10-12 reps is one I can do a 50-60s static contraction with.

[will-work4andro]

Yeah, I do statics for chest for the occlusion effect...since it is impossible to use wraps for that muscle. But you have to do heavy statics - above 65% 1 RM.

i saw an abstract at ACSM last year where they occluded the arms to hypertrophy the chest. the idea was...the triceps would fatigue very quickly calling on a recruitment of more chest

[Venom]

AWESOME idea. What were the results?

[will-work4andro]

AWESOME idea. What were the results?

it was on the bench press and it did in fact induce hypertrophy...specifics i don't remember