Tuesday, March 1, 2011

Does Shaking Out while Climbing Really Work: The Science Says No

Another recent article in the Journal of Strength and Conditioning Research, titled "Active recovery strategies and handgrip performance in trained vs. untrained climbers" had the aim of better understanding active recovery strategies as well as to determine if there are differences in isometric handgrip strength between trained and un-trained climbers.

The intro to the article talks about the usual background info about the nature of the sport and the type of intermittent isometric activity that takes place while climbing.  Much of this information has already been covered in my other reviews, Time Motion Analysis of Bouldering Comps and Injuries in Bouldering.

Compared to untrained climbers, elite level climbers have increased blood flow to the forearms and  take twice as long to fatigue during intermittent isometric contractions.  Surprisingly, there are no differences between trained and un-trained climbers when continuous isometric contractions are used with initial strength controlled for.  In non-scientific terms, elite climbers and untrained climbers show similar decreases in forearm strength if asked to hold a grip for 30 seconds.  However if they are asked to hold the grip for 6 seconds then release for 3 seconds in an intermittent fashion, elite level climbers show much less fatigue.  The authors thus hypothesize that the greater endurance elite climbers have over untrained climbers is related to the amount of blood flow between contractions.

In an effort to recover during a climb, many climbers "shake out" when at a rest stance.  Ask any sport climber and they will tell you that it speeds recovery and increases blood flow, but what does the science say.  The subjects in the study were asked to complete 5 to 11 sets of 6 reps (Reps = 3 second contractions with 1 second rest) and each set was separated by 9 seconds in which the participant would shake out in an effort to recover.  The force required to close the grip device was adjusted based on the initial strength measured on each climber so that the climbers could be compared to each other.  Also the number of sets used varied for the participants based on the level of fatigue the researchers wanted to induce.  Another interesting part of the study is that during certain trials of the experiment participants were required to were a blood pressure cuff during the shake out period in an effort to alter the amount of blood flow to the forearm.

The primary finding of the study was that shaking out did NOT significantly improve intermittent isometric handgrip exercise compared with the control, plain rest.  However the initial advantage elite level climbers had over untrained climbers when intermittent isometric strength was measured seemingly disappeared when the blood pressure cuff was used during recovery.  The authors infer from these results that elite climbers superior performance is more dependent on recovery blood flow in between contractions.  

Ok, so we know that trained climbers have better intermittent isometric contraction endurance and have much higher grip strength than untrained climbers.  Kind of a no brainer if you ask me, but now we have some science behind why that is; better recovery blood flow between contractions.  

I am not convinced with the findings that just plain resting your arm is as beneficial as resting it and shaking it out.  More research needs to be done, specifically research that measures blood flow to the forearm and utilizes various climbing grips.  Squeezing a typical handgrip dynanometer, like the one used in this study does not replicate the demands of the holds encountered in rock climbing.  Also there may be something said about the effect gravity has on the blood in the arm, shaking your arm from high to low may aid in the movement and delivery of blood to the forearm.

Green, J.G. & Stannard, S.R.  Active recovery strategies and handgrip performance in trained vs. untrained climbers. Journal of Strength and Conditioning Research, 24(2) 494-501.



TJ&J said...

Cool write-up. A couple of notes and questions.

1. How do you train for capillary development or increased bloodflow to your forearms? Cardio?

2. I believe a lot of recovery through shaking comes after i>learning<i how to rest and recover. A lot of it is in the mind. Any chump can hang on holds an do the exact same physical motion as an advanced climber, but he does not have the state of mind or the familiarity with recovery to properly focus on his breathing, shake appropriately, and de-weight his hand. I feel as though effective recovery is a learned process.

3. Also, what if shaking is a placebo and the mind learns to relate the motion of shaking with the need to recover and it allows the body to do so? It can be a learned subconscious process...

maybe none of what I just said makes since. I shake, and and somehow it works.

JRucci said...

Thanks for your comments!
1. Endurance training (i.e. sport climbing, repeats on routes, etc) will help build cappillirization in the forearms. The adaptation is similar to what takes place in other area of the bodies that are aerobically stressed.
2. I completely agree, the authors of the article touched on this point. They commented that time would be better spent finding the best rest stance than focusing on shaking out. So you are completely right, the more technique you have, the better the rest stance you are going to use.
3. The placebo effect could have lot to do with it, but placebo effects however loose their efficacy over time. But I do agree that if you condition your body to shake, breathe, relax, and maintain composure, it will become habitual.

Roland said...

This study is beyond flawed. It is astonishing that they conclude that compared with untrained subjects, the performance of trained climbers is more dependent on blood flow (i.e. blood flow correlates highly with performance among climbers), but they do not even consider how the positioning of the arm correlates with blood flow. And yet, they conclude that "shaking out" has no effect on climbing performance, and that there is no need for climbers to find good positions for doing this while on a route. In the study, the subjects performed gripping while hanging their arms vertically down; a position climbers never use in real climbing. The reason you get pumped while climbing is because you hold your arms above your head a long time and use oxygen in your arms while doing so. The reason why "shaking out" works (you don't need a scientific study to show this, it is enough just trying it yourself - the performance difference is huge and very much significant) is that lowering your arm will increase the blood flow temporarily in your arm. One experiment you can try yourself if you do not believe this is to hold your arms above your head for five minutes or so. After a while you will notice that you have exactly the same feeling of pump as you normally have on the climbing wall - without even holding a single hold.
Holding your hands up in the air prevents blood flow not too differently from how using a blood pressure cuff does (as was done in the study to show that blood flow affects performance), i.e. the experiments in the study support the exact opposite conclusion than the one the authors made.