Saturday, October 17, 2009

The Pump: What is it, Does it Work and if so How and for What Kind of Muscle Growth?

ResearchBlogging.orgAhnold reportedly loved "the pump" but what is the "pump" really in terms of muscle building? While it's easy to explain both what happens in generating a pump, and how to create a pump - it's delightfully easy - it's hard to find any evidence behind the incredible claims about why this effect is said to be "essential" to achieving growth.

What is the Pump and How Get One?
Generally speaking the pump is the feeling one gets when pushing more blood into the muscle faster than it will flow out, so for a short time, until it does flow back out to a normal level, the muscle is all "pumped" up, and feels HUGE. This is also where a lot of folks get into nitric oxide products in an effort to extend the effects of the pump. Intriguingly, nitric oxide in studies has only been shown to preserver muscle not help it grow. But that's an aside.

Getting a pump is fun. It's something i've been playing with on my arms after a hard strength workout. I drop the weight to the 12RM weight and do a couple of fast sets (perfect form of course), and then, i'll go to a 20RM for one or two sets of different curls and may only do partials to really get the sweet spot. Bi's one way; tri's the other. What fun! And whip out that measuring tape. Goodness, isn't that remarkable! Strike the pose and take the picture, you bet.

Lack of Pump = Fatigue?
Now all the above does sound easy, but apparently there are times when the pump doesn't seem to be happening. Lonnie Lowery talks about this and suggests, beyond a few high rep 20 sets, making sure the potassium levels are good, and that you're warm not cold (easier vasodilation perhaps) is a good thing. Back off periods and basic carb availability are all good too. Carbs afterall help hold fluid. In fact Lowery has a whole diet here.

Interestingly, Lowery's not making any claims it seems about whether the pump actually helps muscle building or not; he's just saying it's a really nice motivating thing to have: to be able to get HUGE. What's more interesting is Lowery's correlation to lack of getting a pump as a sign of fatigue. Hence his mainly recovery and dietary advice to get that pump back. interesting.

So is this wonderful feeling contributing to muscle growth?

Muscle Hypertrophy 101: the types of muscle hypertrophy
So let's back up a bit. What is muscle growth? We know that there are usually two kinds discussed: sarcoplasmic - the tissue/fluids surrounding muscle fibers - and myofibral - the fibers of the muscles themselves getting bigger due to myofibral growth around the fibers.

It has been argued that power type training privileges myofibril hypertrophy and "hypertrophy" strength training privileges sarcoplasmic - what some folks see as fake hypertrophy because it is non-strength aiding growth of the sarcoplasm of the muscle. This assessment may be a bit cruel. It's actually very hard to get one kind of growth without the other occurring as well. All i'm saying is that different types of strength training may privilege one form over the other, but both will occur. And a good thing too. Myofibral growth demands some adaptation of the sarcomers to support them, too.

Ok, in either case, to the best of our knowledge (because there's a LOT we don't know about hypertrophy) what causes muscles to grow? Forcing them to respond to new demands. If there's no need to adapt do they adapt? well, no. And this is why if one does the same routine forever, the body doesn't change. Folks talk about plateaus. So, we usually use load or volume or a combination of both to create the conditions for adaptation.

Now interestingly, there is work on muscle growth (the strength kind) that has been shown to occur from something called occlusion training. This is where bloodflow is restricted around a limb, and far lighter weights are then used for reps. Intriguingly growth happens.

Ok, so now that we have some background on muscle growth, let's look at how The Pump has been described to help muscle growth

The Pump - per se.
Let's take a look at how the Pump is described to contribute to muscle growth first. An un-cited article on by "muscleTech" puts it this way:
The release of nitric oxide facilitates the relaxation of the endothelial cells — smooth muscles that line the blood vessels — thereby expanding the lumen of the blood vessel (the middle space of a blood vessel where blood flows through). As the lumen expands, blood flow is enhanced, resulting in peak vasodilation. Blood plasma is the primary channel through which nutrients, amino acids, testosterone, growth hormone (GH) and insulin-like growth factor 1 (IGF-1) are delivered to your starving muscles. Therefore, by feeding your system more blood, you transport elevated amounts of the various musclebuilding catalysts directly to your hard-working muscle cells.
Another example of how the pump powers growth is through the role of oxygen. Increasing the delivery of oxygen-rich red blood cells to your starving muscles accelerates the speed at which your system is able to cleanse itself of muscle toxins such as ammonia.

Achieving maximum vasodilation also allows your body to quickly deliver metabolized amino acids and nutrients that are derived from your pre- and post-workout nutrition, and shuttle them directly to your hypertrophying muscles — allowing for enhanced muscle recovery and growth
Wow. There's a lot going on in there. What it really seems to say is that more is better. Open a Bigger Pipe to let More Stuff through. Push through more blood with more protein, growth factor, testosterone all pushed into to muscles. That must be good right? Really? And even more fresh blood to push out "muscle toxins" would be great too, right? Hmm.

Alas, no sources in the article to support these assertions.

Another theory of the pump expressed by Jeff Anderson is that the pump actually privileges slow twitch muscle fibers. That makes sense for two reasons: lots of low weight reps is moving into endurance world, which means oxidative capacity, aerobic energy rather than anaerobic capacity/ernergy. So Mr. Anderson says that by constantly pushing blood into these fibers, the fibers themseleves adapt to hold more blood. That means more capillaries in the fibers to help shunt the blood more effectively, and they're going to be rather densely packed as their numbers go up.

So you get the sense from this explanation that size noticed to hold more blood more of the time is going to make the muscle appear larger. Sarcoplasmic kind of growth?

Here's why i go more for Mr. Anderson's than MuscleTech's explanation. Our tissues are always adapting. If you squish more into them, they'll start to enlarge. So that's kinda funny - it's adding fluid (blood etc) into the muscle, but not increasing the number of myofibrils. So that doesn't sound like a strength gain; sounds more sarcoplasmic.

The Pump: can we get some science in here? Not easily.
The pump seems to work with two sides of something called hyperemia - active and reactive. The active one is caused by muscle contraction - do that a lot in exercise, eh? - which causes blood to congest in an area. Then there's reactive hyperemia - where blood that's supposed to get out is blocked - like there's a tourniquet causing yup, occlusion.

So, if there's occlusion, that means that blood is kinda stuck somewhere. That doesn't sound like blood is getting forced through to clear out "muscle toxins" or to induce the other popular concept of "muscle flushing" - sounds like it's getting stuck and stale.

If we look at "hyperemia" & "resistance training" in the science literature, we don't find stuff about muscle building. The kind of literature that's there is about the degree to which different kinds of training enhance the flow of blood or the dilation of the arteries. In other words, we generally apparently want to reduce reactive hyperemia.

Now while i've seen claims that moderate rep schemes are "are optimal to build muscle mass " because in part they "Enhances cellular hydration — greater muscle pump (called "reactive hyperemia") drives plasma and water to muscle which stimulates protein synthesis and inhibits proteolysis (protein breakdown)." i can't find any sources that explain that plasma and water driven to a muscle stimulates protein synthesis. We do know is that protein stimulates muscle synthesis. And we know that insulin stimulates protein synthesis and glucose stimulates protein synthesis. So maybe if there's all that stuff in plasma, yes we have protein synthesis stimulation. But that seems to happen whether we have high or low rep training. But again, is more more?

An Idea: the Pump Works Like Occlusion?
Mr. Anderson above proposes that the pump mainly effects slow twitch oxidative fibers because of capilarization (no strength; just mass). Dr. Lowery suggests that not being able to get a pump is a sign of fatigue - this i think is important. BUT if we look at occlusion training (which reactive hyperemia seems to be a type), then the pump should also be affecting both fast and slow twitch fibers' myofibral growth. Occlulusion, it seems, may indeed get fast twitch fibers involved more directly than without occlusion - that's a theory. Since we also see in low load occlusion training effects on strength: it goes up. SO is this kind of self-occlusion with self-selected low resistance weights to induce the effect having the same effect as a cuff? Could be - as per this review.

So, what about that pump?
Proposal 1: more is more: As far as i can tell, the suggestions are that it's supposed to help circulate good stuff in by vasodilateion, and then get the stale stuff out. Now for me - based on what i know - this seems the weakest case since we're not talking about steady blood flow in and out with the pump, but "reactive hyperemia" which means that blood is pumped in, and it can't get out again for a good half hour. There's no "flushing" if that's the case is there? Dave Barr talks about the "anabolic pump" - but again, i can't find this in the literature.

Proposal 2: bulking up with fluid. The other proposal that anderson suggests - and i'm not sure where he gets it from, but seems to make sense, is that pushing a lot of blood into the veins - especially of slow twitch fibers - is going to cause the fibers that hold the blood to adapt - get thicker, more and denser capillaries (the little gates that open for blood to flow in but not back out). SO that's just bulking up - what most folks talk about as sarcoplasmic type hypertrophy - but this seems even more particular as it's strictly related to blood volume taking up more room.
Proposal 3: occlusion causing real muscle fiber change - or not. What makes more sense to me is a combo of this adaptation of capillaries AND actual fiber change potentially caused by self-occlusion. BUT folks like Chad Waterbury, respected strength coach, are very skeptical of the pump and any correlation to muscle gain.
No, look, lots of things give you a pump but don't make your muscles bigger. One of the best exercises I know for making your calves bigger is the jump squat, which doesn't cause a pump. But if you do a set of 50 calf raises, you'll get one hell of a pump, but it won't make your calves bigger.
SO perhaps 50 calf raises aren't causing occlusion but then how could they cause a pump? I don't understand. Perhaps those calf raises do add muscle fiber but not mass? perhaps calves like abs are different? dunno. Interesting though.

Maybe, Maybe Not, It depends
As said, there's a lot that remains unknown about the whys and hows of hypertrophy. The role of the pump seems to be just as really clearly ambiguous as to whether or not it aids hypertrophy or not.

I like the correlation Lowery seems to make implicitly between achieving the pump and fatigue. That seems useful.

For myself, right now, it's fun to play with a pump well after i've completed the hard work of the strength workouts i'm doing. Whether it's doing anything functional or not, i dunno, but since there seems *some* sense to it, i'm willing to give it a bit of a go - for now.

And so... The above is not meant as an exhaustive overview of all things to do with the pump - it's just what i could find by a couple day's digging. IF there are studies that you know of that support or study the pump with respect to muscle hypertrophy, please add a comment. Will be keen to hear.

I wonder too if a study that took the same kind of athletes and one did a regular routine and the other finished with pump sets and the other didn't if that would be conclusive or that one would just say - well they other group did a bit more volume. I suppose one could vary the loads or reps. But it would be interesting to see some kind of work.

Also, i do know that just because it hasn't been researched doesn't mean there's not an effect, but as per that first "explanation" of why the pump works - supposedly - for hypertrophy - if one is going to provide physiological rationales for an effect, please just point to the mechanisms that have been shown to result in these effects - it has to be sourced somewhere. And if not, well, the best we can say is that, in some cases, there seems to be a strong correlation between pumping and hypertrophy - either sarcoplasmic or myofibral - what that mechanism is - pretty much unknown at the moment.

Again - this is just the best i can do right now to make sense of this concept. If you have more information/sources, please share.


Related Posts:

Wernbom M, Augustsson J, & Raastad T (2008). Ischemic strength training: a low-load alternative to heavy resistance exercise? Scandinavian journal of medicine & science in sports, 18 (4), 401-16 PMID: 18466185

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


Roland Fisher said...

Great review mc. I too have never seen anything convincing regarding the pump. I do notice that folks who train, and either coincidently or purposefully, achieve a pump in training, seem to get better results.

So I guess I too am looking forward to any posts that shed some more light.

Roland Fisher said...

I should have added to my previous post, great info from Lowery. He's my favorite nutrition guy for a lot of reasons, but that advice about fatigue is a very useful, actionable idea.

Thanks for that.


Related Posts with Thumbnails