Friday, July 24, 2009

Occlusion training: Sparking Muscle Growth when Injured or Just Sick of Heavy Loads

ResearchBlogging.orgWhen 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.
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.
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.

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:

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

2 comments:

Mike T Nelson said...

What are your thoughts about some data showing altered EGM activation during occlusion? I wonder if we may be increasing the muscle size, but making it dumber?

Thoughts on occlusion, lift, then release the cuff vs leaving the cuff on for the duration of all sets?

Rock on!
Mike T Nelson
Extreme Human Performance

mc said...

super duper questions, mike.

i wonder though if in especially coming back from an injury the benefits outweigh the dumbness to get to a place where you can more rapidly get strong enough to do mobility?

here's where it would be nice to do a comparison with z, say, mobilizing other joints, looking at healing effect in comparison with this kind of muscle based recovery, you know?

mc

ShareThis

Related Posts with Thumbnails