Showing posts with label muscle growth. Show all posts
Showing posts with label muscle growth. Show all posts
Sunday, February 14, 2010
Hypoxia for Muscle Growth: Get Huge or Die?
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A recently accepted paper shows that working in an oxygen deprived environment can gosh darn it, build muscle when doing resistance work. WHile jokes might start about the variety of ways that one could replicate a near-asphyxiated space - from smoking to putting a plastic bag (with some holes) over one's head - i'm thinking that in the case of resistance training (as opposed to altitude/endurance where there's a definite blood/muscle adaptation), based on the findings, we're maybe seeing predictably heightened threat response brought on by 02 deprivation. Here's a look at the study in detail:
What is it with Japanese research and oxygen deprivation? They bring us the most amazing results of occlusion training (b2d discussion here). Now, how about whole body oxygen occlusion?
Some may argue that this seems to be similar to training at altitude, where the benefits are known. Indeed, the authors use a system that's used to generate Everest-like conditions, funnily enough called an "everest generator" and for 5K you can have one, too (shown left).
Thing is, this technique is most often used for endurance athletes (and we've also seen in cycling for instance blood doping associated cases of EPO enriched/adapted blood), and apparently the usual oxygen depletion levels are 20.9% o2 - with associated increased risks of overtraining. Here, in this resistance training study, the researchers use 13ish% o2.
Another unique aspect of this hypoxia study is it's the first time (to my knowledge anyway) researchers have formally looked at effects on resistance training - anaerobic effort as opposed to aerobic effort.
The Rationale: it IS occlusion training. The authors do indeed say yup well, LOW INTENSITY resistance training and partial occlusion has great effect, so how about "systemic hypoxia" - It's the next logical step, isn't it?
Set Up. 10 reps of bench and squat at 70% of tested 1RM in either normal room air or 13% O2. I'm only able to guess that 13% is some standard definition of "acute hypoxia" conditions that are still safe.
The authors alas don't formally justify either why they were going for this percentage or why this definitely NOT low resistance level (like occlusion training uses) was used.
All sorts of Measures. The purpose of the trials were so the researchers will have
And what all the lads love to hear: serum GH - significantly higher in the hypoxia case (potentially triggered, the researchers suppose by increased catecholamine release) Likewise IGF and of course yes the big T, testosterone. But so does cortisol.
And for those trying to burn fat? Not surprisingly to folks who see the world through the nervous system threat/no threat lense, those wonderful fight or flight catecholamines are of course elevated, too. These are the things that help fat mobilisation (discussed here in this b2d piece on HIIT). So gosh, let's see - challenge trying to breath - i'd say that's going to be perceived as a threat to one's system?
So What's Different (than occlusion training)?
The authors suggest that while occlusion training has shown greater muscle growth, they haven't really known why. They put it down to the increased levels of GH noted in occlusion training at LOW REPS. Here they're saying
What they say their specific results also suggest is that IGF-1 may be indedpendent of GH levels. In other words, something else is going on to get a boost in IGF-1 than the presence of GH.
Likewise, they suggest that increases in serum testosterone may have more to do with intensity and muscle mass than "metabolic stress" - like hypoxia.
As for cortisol, another fight or flight hormone, that's also a known biproduct of resistance training. The researchers say they just don't know what the mechanism is such that these levels are particularly higher in this trial. Well heck, again, threat-related hormone; gonna asphixiate. Dunno. seems predictable when seen from that vantage?
Not Normal. The threat hormones did not return to normal levels within an hour after the trials either. Is that good? Not clear, but if overtraining is related to stressing they system, threatening it more than it can handle perhaps, then it's reasonable to see why this kind of training may need to be far more closely monitored for overtraining effects.
Openning New Doors. The biggest outcome it seems right now is the possible relationship of hypoxia to GH - at least in the authors' view:
hypoxic environment in anaerobic work like resistance training - hence the term anaerobic - so it's interesting to see therefore that the hypoxic effect seems to be perhaps on the recovery - where we usually pause between sets to catch our breath and re-oxygenate. Here, in this o2 deprived envrionment, that can't happen. Hence lactate it seems to me goes up. And GH switches in.
Why, when the nervous system might be percieved to be under threat, would the nervous system/brain see this as a good time to, er, grow? (For a review of the systems that get shut down under stress, see this overview of Zebras and Baboons and Stress.)
Again, what these researchers don't seem to clue into is that growth hormone is apparently known to be triggered by stress (and here's a pdf from 76 about how kind of cool this is, where only 1/3 of the sample group was shown to have this particular stress/GH release response). It's role this work shows, is not just to grow the body, but the brain. Is that what's going on? I'm about to die; i suddenly need a bigger brain?
Ramdoc, over at the dragondoor forum (thank you), made the intriguing connexion that GH is related to insulin. Here's 2005 paper outlining the human GH/insulin homeostasis, and that bigger hits of GH lead to a hyperinsulinism - elevated levels of insulin in the bloodstream. That's gonna trigger a temporary blood glucose surge. So if increased GH relates to a rush of glucose to the bloodstream, that certainly would have a survival effect. More fast energy, that means more ATP, more muscle can be recruited, more speed, steve. Cool.
We're about to Die; Let's get Huge?
Well who'd have thought even to test the effects of cutting off c
irculation to see what would happen to our bodies?
I suppose it's an interesting idea - take a process like anaerobic metabolism and string it out to see if by seeing what happens in a less natural environment, we get some better view into a natural environment. And heck, some folks might turn that practice into a way to rehab and train folks.
The responses seen in this environment - a big fat rush of fight or flight related responses - seem pretty predictable. That there's a positive payoff FROM that stress after the event is interesting: survive and get faster, stronger. Recovery means anabolism: more muscle, continued performance improvement. And who knows? Maybe a bigger smarter brain?
But in terms of pushing this principle that's being expressed in the large in this oxygen deprived space? The biggie that those stress levels don't go back to normal in normal time is a reminder that hypoxia work may just be super stressful to our CNS even if we mayn't perceive that directly ourselve - and this study doesn't tell us if it collected any of the athletes' responses to the protocol.
In the meantime, for those who are curious, how would one try this at home without an Hypoxia Generator? The mind reels at the possibilities.
Related Posts
A recently accepted paper shows that working in an oxygen deprived environment can gosh darn it, build muscle when doing resistance work. WHile jokes might start about the variety of ways that one could replicate a near-asphyxiated space - from smoking to putting a plastic bag (with some holes) over one's head - i'm thinking that in the case of resistance training (as opposed to altitude/endurance where there's a definite blood/muscle adaptation), based on the findings, we're maybe seeing predictably heightened threat response brought on by 02 deprivation. Here's a look at the study in detail:
Med Sci Sports Exerc. 2009 Dec 14. [Epub ahead of print]
Effects of Acute Hypoxia on Metabolic and Hormonal Responses to Resistance Exercise.
Kon M, Ikeda T, Homma T, Akimoto T, Suzuki Y, Kawahara T.
1Department of Sports Sciences, Japan Institute of Sports Sciences, 3-15-1 Nishigaoka, Kita, Tokyo, 115-0056, Japan; 2Laboratory of Regenerative Medical Engineering, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan.
INTRODUCTION:: Several recent studies have shown that resistance exercise combined with vascular occlusion effectively causes increases in muscular size and strength. Researchers speculated that the vascular occlusion-induced local hypoxia may contribute to the adaptations via promoting anabolic hormone secretions stimulated by local accumulation of metabolic subproducts. Here we examined whether acute systemic hypoxia affects metabolic and hormonal responses to resistance exercise. METHODS:: Twelve male subjects participated in two experimental trials: 1) resistance exercise while breathing normoxic air [normoxic resistance exercise (NR)], 2) resistance exercise while breathing 13 % oxygen [hypoxic resistance exercise (HR)]. The resistance exercises (bench-press and leg-press) consisted of 10 repetitions for five sets at 70 % of maximum strength with 1-min rest between sets. Blood lactate, serum growth hormone (GH), epinephrine (E), norepinephrine (NE), insulin-like growth factor 1 (IGF-1), testosterone, and cortisol concentrations were measured before normoxia and hypoxia exposures, 15-min after the exposures, and at 0, 15, 30, 60 min after the exercises. RESULTS:: Lactate significantly increased after exercises in both trials (p < style="color: rgb(153, 51, 0);">These findings suggest that resistance exercise in hypoxic condition caused greater accumulation of metabolites, and strong anabolic hormone response.
What is it with Japanese research and oxygen deprivation? They bring us the most amazing results of occlusion training (b2d discussion here). Now, how about whole body oxygen occlusion?
Some may argue that this seems to be similar to training at altitude, where the benefits are known. Indeed, the authors use a system that's used to generate Everest-like conditions, funnily enough called an "everest generator" and for 5K you can have one, too (shown left).Thing is, this technique is most often used for endurance athletes (and we've also seen in cycling for instance blood doping associated cases of EPO enriched/adapted blood), and apparently the usual oxygen depletion levels are 20.9% o2 - with associated increased risks of overtraining. Here, in this resistance training study, the researchers use 13ish% o2.
Another unique aspect of this hypoxia study is it's the first time (to my knowledge anyway) researchers have formally looked at effects on resistance training - anaerobic effort as opposed to aerobic effort.
The Rationale: it IS occlusion training. The authors do indeed say yup well, LOW INTENSITY resistance training and partial occlusion has great effect, so how about "systemic hypoxia" - It's the next logical step, isn't it?
Set Up. 10 reps of bench and squat at 70% of tested 1RM in either normal room air or 13% O2. I'm only able to guess that 13% is some standard definition of "acute hypoxia" conditions that are still safe.
The authors alas don't formally justify either why they were going for this percentage or why this definitely NOT low resistance level (like occlusion training uses) was used.
All sorts of Measures. The purpose of the trials were so the researchers will have
examined the effects of resistance exercise on metabolic and hormonal responses under acute systemic hypoxia. We hypothesized that the resistance exercise in hypoxic condition would cause greater accumulation of metabolic subproducts, and greater responses of anabolic hormones.To this end, a lot of measures were taken of muscle oxidation, hormones, fuel produced (like lactate). As the abstract says, blood lactate levels were significantly higher in the hypoxia trial than in the normal air trial. This isn't much of a surprise, given that lactate tends to kick in as it gets harder for the body to oxidize fuel in the mitochondria. A goal of Vo2max training (like viking warrior conditioning, reviewed here) is to increase the lactate threshold - the level of effort and time before which bi products of lactate production (H+ ions) can no longer be buffered out of the blood.
And what all the lads love to hear: serum GH - significantly higher in the hypoxia case (potentially triggered, the researchers suppose by increased catecholamine release) Likewise IGF and of course yes the big T, testosterone. But so does cortisol.
And for those trying to burn fat? Not surprisingly to folks who see the world through the nervous system threat/no threat lense, those wonderful fight or flight catecholamines are of course elevated, too. These are the things that help fat mobilisation (discussed here in this b2d piece on HIIT). So gosh, let's see - challenge trying to breath - i'd say that's going to be perceived as a threat to one's system?
So What's Different (than occlusion training)?
The authors suggest that while occlusion training has shown greater muscle growth, they haven't really known why. They put it down to the increased levels of GH noted in occlusion training at LOW REPS. Here they're saying
In the present study, we revealed that systemic hypoxia was actually associated with greater GH response to resistance exercise for the first time. The hypoxia may play a key role in the low intensity resistance training with vascularInteresting that systemic hypoxia is being used to understand the mechanisms of a more local phenomena like Kaatsu cuffing.
occlusion-induced muscular hypertrophy
What they say their specific results also suggest is that IGF-1 may be indedpendent of GH levels. In other words, something else is going on to get a boost in IGF-1 than the presence of GH.
Likewise, they suggest that increases in serum testosterone may have more to do with intensity and muscle mass than "metabolic stress" - like hypoxia.
As for cortisol, another fight or flight hormone, that's also a known biproduct of resistance training. The researchers say they just don't know what the mechanism is such that these levels are particularly higher in this trial. Well heck, again, threat-related hormone; gonna asphixiate. Dunno. seems predictable when seen from that vantage?
Not Normal. The threat hormones did not return to normal levels within an hour after the trials either. Is that good? Not clear, but if overtraining is related to stressing they system, threatening it more than it can handle perhaps, then it's reasonable to see why this kind of training may need to be far more closely monitored for overtraining effects.
Openning New Doors. The biggest outcome it seems right now is the possible relationship of hypoxia to GH - at least in the authors' view:
... it is necessary to investigate whether hypoxic exposure plays an important role for the expressions of genes involving muscular hypertrophy in the future...Our data suggest that hypoxia is a potent factor for the enhancements of anabolic hormone (GH) response to resistanceWhy when fleeing the Tiger does GH turn on? Intriguingly, we already induce a kind of
hypoxic environment in anaerobic work like resistance training - hence the term anaerobic - so it's interesting to see therefore that the hypoxic effect seems to be perhaps on the recovery - where we usually pause between sets to catch our breath and re-oxygenate. Here, in this o2 deprived envrionment, that can't happen. Hence lactate it seems to me goes up. And GH switches in.Why, when the nervous system might be percieved to be under threat, would the nervous system/brain see this as a good time to, er, grow? (For a review of the systems that get shut down under stress, see this overview of Zebras and Baboons and Stress.)
Again, what these researchers don't seem to clue into is that growth hormone is apparently known to be triggered by stress (and here's a pdf from 76 about how kind of cool this is, where only 1/3 of the sample group was shown to have this particular stress/GH release response). It's role this work shows, is not just to grow the body, but the brain. Is that what's going on? I'm about to die; i suddenly need a bigger brain?
Ramdoc, over at the dragondoor forum (thank you), made the intriguing connexion that GH is related to insulin. Here's 2005 paper outlining the human GH/insulin homeostasis, and that bigger hits of GH lead to a hyperinsulinism - elevated levels of insulin in the bloodstream. That's gonna trigger a temporary blood glucose surge. So if increased GH relates to a rush of glucose to the bloodstream, that certainly would have a survival effect. More fast energy, that means more ATP, more muscle can be recruited, more speed, steve. Cool.
We're about to Die; Let's get Huge?
Well who'd have thought even to test the effects of cutting off c
irculation to see what would happen to our bodies?I suppose it's an interesting idea - take a process like anaerobic metabolism and string it out to see if by seeing what happens in a less natural environment, we get some better view into a natural environment. And heck, some folks might turn that practice into a way to rehab and train folks.
The responses seen in this environment - a big fat rush of fight or flight related responses - seem pretty predictable. That there's a positive payoff FROM that stress after the event is interesting: survive and get faster, stronger. Recovery means anabolism: more muscle, continued performance improvement. And who knows? Maybe a bigger smarter brain?
But in terms of pushing this principle that's being expressed in the large in this oxygen deprived space? The biggie that those stress levels don't go back to normal in normal time is a reminder that hypoxia work may just be super stressful to our CNS even if we mayn't perceive that directly ourselve - and this study doesn't tell us if it collected any of the athletes' responses to the protocol.
In the meantime, for those who are curious, how would one try this at home without an Hypoxia Generator? The mind reels at the possibilities.
Related Posts
- Threat response - movement
- Catecholamines release in HIIT
PDF
Friday, July 24, 2009
Occlusion training: Sparking Muscle Growth when Injured or Just Sick of Heavy Loads
Follow @mcphoo
Tweet
When we hear the words "muscle hypertrophy" most of us think of body building and super duper muscle mass.
But hypertrophy itself is a natural and indeed necessary part of strength development. And it can be hard to induce hypertrophy when coming back from an injury or just when pooped of dealing with heavy weig Occlusion training (restricting venus return for very short periods) has intriguingly been associated with muscle hypertrophy. This recent review shows that its combined use with low loads can be great for rehab of ACL injuries as well as general athletic prep.
Great scott. Do you see capitol letters as shouting? this authors must be really excited about the research.
The part that is exciting is that if you can give a population a way to train their muscles and build their muscles at loads that are much lighter that what would be needed otherwise, you can imagine that the opportunities to get repair happening or growth happening could be, er, huge. Hypertrophy huge.
So let's take a quick peek at what hypertrophy is understood to be, and then at how occlusion training is generally applied.
Hypertrophy. Well, we know that if bodybuilders talk about hypertrophy they're talking about building muscle mass. But as said, anyone developing strength will get some hypertrophy happening. Why? How do we get stronger? That's complicated, but a simplified model would be: in the first instance, we are learning simply how to fire the muscles we have to do some new task, like lifting something heavy. So for someone who's never lifted, when starting a lifting program, say, they make big leaps in their strength in the first 8-12 weeks. A lot of that is neurological.
The other part of muscle building is laying down new muscle fibers to deal with trauma. When we train, we break down muscle tissue often deliberately in order to create an adaptation/growth. SO muscle literally gets pulled apart from time to time. Ironically, that is not what causes delayed onset muscle soreness (or DOMS). DOMS hits 24 - 48 hours after working out muscles (hence the delay part) and some theories are that it's the result of new muscle fibers butting up against each other and settling in - so it's the repair process rather than the damage process that is painful. Neat.
Which brings us to hypertrophy, in particular myofibrillated hypertrophy, which is the laying down of new actual muscle fibers or myofibrils. These are tiny fibers and not where the body builders' bulk comes from. That's generally sarcoplasmic - also important to protect the myofibrils and usually goes hand in hand with myofibrillated hypertrophy. We'll come back to that another time. Suffice it to say, what kind of growth is where sets, reps and REOCVERY come into play in terms of this balance and which kind of hypertrophy a program is privileging.
So let's say we're looking at getting the muscles around a knee injury built back up. The person is at a place where they can body squat, maybe do some light weight work, but (a) it may not be desireable for the person to do TONS of reps, but unless they do tons of reps with a light weight, desired hypertrophy - new muscle tissue growth - is not going to happen. Enter this really cool aspect of hypertrophy training, Occlusion training.
Likewise, OT *may* be useful to give athletes a break from high load work. Note, this does not mean do OT during a back off weak: the whole point of a back off weak is to let the body recover, not push it to adapt further.
Occlusion Training. Occlusion is a beautiful sounding word, isn't it? It's usually seen in visual contexts - to occlude something is to block it from view. If you put your mother's picture in front of that ugly stone someone gave you from their holiday in Crete, you have occluded the view of the offensive object that your loved ones won't let you chuck.
In occlusion training, we're talking about another kind of block. In this case, blocking the flow of blood - a bit, and for intervals. So what? How can that be good?
Well, an idea is, restricting blood flow causes fast twitch fibers to get involved in the process sooner than they otherwise would. Likewise a biggie in the effect is the production of blood by-products, and ones that trigger significant increases in GH. (i have visions now of Mike Mahler tying up his quads while doing lightweight kettlebell swings).
Caveats of Application. SO when we talk about restricting blood flow, what are we really talking about? IF we cut it off, don't our limbs drop off? Well, yes. So here, we're talking about restriction as opposed to total constriction, and also for particular intervals. And for light loads.
Ok what does that mean in practice? There are a variety of approaches described in the article that involve walking and the effects on strength. Pretty cool stuff. The authors, however, offer a sample protocol for strength:
from the article: note binding for knee work is at the top of the thigh - the proximal end of the vastus
The above is not encouragement to go try tying off your friend's legs and asking them to jump around :) As the authors state about future work:
Loenneke, J., & Pujol, T. (2009). The Use of Occlusion Training to Produce Muscle Hypertrophy Strength and Conditioning Journal, 31 (3), 77-84 DOI: 10.1519/SSC.0b013e3181a5a352 Tweet Follow @begin2dig
When we hear the words "muscle hypertrophy" most of us think of body building and super duper muscle mass.But hypertrophy itself is a natural and indeed necessary part of strength development. And it can be hard to induce hypertrophy when coming back from an injury or just when pooped of dealing with heavy weig Occlusion training (restricting venus return for very short periods) has intriguingly been associated with muscle hypertrophy. This recent review shows that its combined use with low loads can be great for rehab of ACL injuries as well as general athletic prep.
The Use of Occlusion Training to Produce Muscle Hypertrophy
Loenneke, Jeremy Paul BS; Pujol, Thomas Joseph EdD, CSCS
Strength and Conditioning Journal:
June 2009 - Volume 31 - Issue 3 - pp 77-84
doi: 10.1519/SSC.0b013e3181a5a352
Articles
LOW-INTENSITY OCCLUSION (50-100 MM HG) TRAINING PROVIDES A UNIQUE BENEFICIAL TRAINING MODE FOR PROMOTING MUSCLE HYPERTROPHY. TRAINING AT INTENSITIES AS LOW AS 20% 1 REPETITION MAXIMUM WITH MODERATE VASCULAR OCCLUSION RESULTS IN MUSCLE HYPERTROPHY IN AS LITTLE AS 3 WEEKS. A TYPICAL EXERCISE PRESCRIPTION CALLS FOR 3 TO 5 SETS TO VOLITIONAL FATIGUE WITH SHORT REST PERIODS. THE METABOLIC BUILDUP CAUSES POSITIVE PHYSIOLOGIC REACTIONS, SPECIFICALLY A RISE IN GROWTH HORMONE THAT IS HIGHER THAN LEVELS FOUND WITH HIGHER INTENSITIES. OCCLUSION TRAINING IS APPLICABLE FOR THOSE WHO ARE UNABLE TO SUSTAIN HIGH LOADS DUE TO JOINT PAIN, POSTOPERATIVE PATIENTS, CARDIAC REHABILITATION, ATHLETES WHO ARE UNLOADING, AND ASTRONAUTS.
Great scott. Do you see capitol letters as shouting? this authors must be really excited about the research.
The part that is exciting is that if you can give a population a way to train their muscles and build their muscles at loads that are much lighter that what would be needed otherwise, you can imagine that the opportunities to get repair happening or growth happening could be, er, huge. Hypertrophy huge.
So let's take a quick peek at what hypertrophy is understood to be, and then at how occlusion training is generally applied.
Hypertrophy. Well, we know that if bodybuilders talk about hypertrophy they're talking about building muscle mass. But as said, anyone developing strength will get some hypertrophy happening. Why? How do we get stronger? That's complicated, but a simplified model would be: in the first instance, we are learning simply how to fire the muscles we have to do some new task, like lifting something heavy. So for someone who's never lifted, when starting a lifting program, say, they make big leaps in their strength in the first 8-12 weeks. A lot of that is neurological.
The other part of muscle building is laying down new muscle fibers to deal with trauma. When we train, we break down muscle tissue often deliberately in order to create an adaptation/growth. SO muscle literally gets pulled apart from time to time. Ironically, that is not what causes delayed onset muscle soreness (or DOMS). DOMS hits 24 - 48 hours after working out muscles (hence the delay part) and some theories are that it's the result of new muscle fibers butting up against each other and settling in - so it's the repair process rather than the damage process that is painful. Neat.
Which brings us to hypertrophy, in particular myofibrillated hypertrophy, which is the laying down of new actual muscle fibers or myofibrils. These are tiny fibers and not where the body builders' bulk comes from. That's generally sarcoplasmic - also important to protect the myofibrils and usually goes hand in hand with myofibrillated hypertrophy. We'll come back to that another time. Suffice it to say, what kind of growth is where sets, reps and REOCVERY come into play in terms of this balance and which kind of hypertrophy a program is privileging.So let's say we're looking at getting the muscles around a knee injury built back up. The person is at a place where they can body squat, maybe do some light weight work, but (a) it may not be desireable for the person to do TONS of reps, but unless they do tons of reps with a light weight, desired hypertrophy - new muscle tissue growth - is not going to happen. Enter this really cool aspect of hypertrophy training, Occlusion training.
Likewise, OT *may* be useful to give athletes a break from high load work. Note, this does not mean do OT during a back off weak: the whole point of a back off weak is to let the body recover, not push it to adapt further.
Occlusion Training. Occlusion is a beautiful sounding word, isn't it? It's usually seen in visual contexts - to occlude something is to block it from view. If you put your mother's picture in front of that ugly stone someone gave you from their holiday in Crete, you have occluded the view of the offensive object that your loved ones won't let you chuck.
In occlusion training, we're talking about another kind of block. In this case, blocking the flow of blood - a bit, and for intervals. So what? How can that be good?
Well, an idea is, restricting blood flow causes fast twitch fibers to get involved in the process sooner than they otherwise would. Likewise a biggie in the effect is the production of blood by-products, and ones that trigger significant increases in GH. (i have visions now of Mike Mahler tying up his quads while doing lightweight kettlebell swings).
Caveats of Application. SO when we talk about restricting blood flow, what are we really talking about? IF we cut it off, don't our limbs drop off? Well, yes. So here, we're talking about restriction as opposed to total constriction, and also for particular intervals. And for light loads.
Ok what does that mean in practice? There are a variety of approaches described in the article that involve walking and the effects on strength. Pretty cool stuff. The authors, however, offer a sample protocol for strength:
A typical low-intensity prescription would involve an intensity of 20-50% of 1RM with a 2-second cadence for both the concentric and eccentric actions. The 1RM is calculated from the maximum amount of weight you can lift once under normal blood flow conditions. Three to five sets of each exercise are completed to volitional fatigue. This is done to ensure that there is a high metabolic buildup. The rest periods are 30 seconds to 1 minute in length and occur between every set, with the occlusion still being applied (5,6,27,35,36,39). At the conclusion of the last set, blood flow is restored to the muscle.Again, the important take away here is LIGHT loads for a few sets. Likewise the PROXIMAL end of the targetted muscle is what gets bound, as shown in the image below.
Cook et al. (6) compared different protocols of occlusion using percent maximal voluntary contraction (%MVC) and found that 20% MVC with continuous partial occlusion was the only protocol that elicited significantly more fatigue than the higher intensity protocol.
from the article: note binding for knee work is at the top of the thigh - the proximal end of the vastusThe above is not encouragement to go try tying off your friend's legs and asking them to jump around :) As the authors state about future work:
Future research on occlusion training should focus on studying the health risks associated with long-term use and determine populations in which this type of training may be contraindicated (6). Although the research has yet to define populations in which occlusion training is dangerous, we postulate that those with endothelial dysfunction should not use occlusion training because of the reduction in blood flow. Research should also further study the microdamage to blood vessels and subtle changes in blood flow, both of which may stimulate thrombosis (38). Also, one should seek to evaluate the gene expression at later stages of postexercise recovery after occlusion and in response to occlusion training (7). Finally, studies should begin to focus on the local regulators of muscular growth, such as growth factors and reactive oxygen species, to elucidate the mechanism for the present cooperative effects of exercise and occlusive stimuli (39).Take away: if you're looking to build up strength especially after an injury, short term use of occlusion training may be a good way to get back in the game. Likewise, if you're getting fatigued by heavy lifting or jus the thought of having to pick up a really heavy bar to make a difference is getting you down, doing some short term occulsion sets because of their effective LOW reps and LIGHT weight, may be just the thing to keep you training and provide the mental break necessary to get back at it.
Loenneke, J., & Pujol, T. (2009). The Use of Occlusion Training to Produce Muscle Hypertrophy Strength and Conditioning Journal, 31 (3), 77-84 DOI: 10.1519/SSC.0b013e3181a5a352 Tweet Follow @begin2dig
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