Brainy muscles

A recent story in The New York Times by Gina Kolata, one of my favorite science writers, highlights one reason why I think neuroanthropology has to be broader than ‘cognitive anthropology’ was in the 1980s and 1990s (and why ‘cognitive science’ itself has really expanded with the more recent wave of thinking about embodied cognition). In an article on whether or not weight training is really good for athletes, titled Does Weight Lifting Make a Better Athlete?, I think Kolata does a much better job presenting the case for the efficacy of weight training than the arguments against it. Even several of the physiologists and trainers who Kolata suggests are less than rapt with weight training make comments that are more specifically about weight training done badly than against the practice as a whole; they criticize poor form, badly designed programs, and even not working hard enough, hardly criticisms of the overall efficacy of weight training.

Most of the athletes and other experts seem to me to be pretty strongly in favor of weight training, and I have no doubt that there’s good reason. Most athletic training has been radically transformed with the advent of weight training, and approaches that have come out of weight training (such as targeting specific muscle groups and working different parts of the body to failure) are also applied even in non-weight training exercises, such as selective sprinting, whole body exercises, and the like. Some of my research on capoeira, no-holds-barred fighting (or MMA), and other forms of wresting training suggest that actually training with ‘weights’ — barbells, dumbbells, and the like — can be less than ideal, but most of the modifications that this research suggests are consistent with the theory and practice of weight training, even if they expand the activities involved (body weight exercises, whole body dynamic lifting, jumping, etc.).

But one of the few critics says something that I found extremely interesting, and it resonated with some of the stuff I’ve been writing in my sports-related manuscript (hopefully a book soon) about how neural plasticity affects athletic performance. Specifically, Dr. Patrick O’Connor, a University of Georgia exercise scientist, says that ‘a sport like rowing, swimming or running requires specific muscles and nerve-firing patterns that may best be developed by actually doing the sport.’ A sport like ‘rowing, swimming or running’ that ‘requires specific muscles and nerve-firing patterns…’ hmmmm? So that would be like, what, every sport?


The point is that, as research on strength training and visualization has shown, the nervous system contributes an enormous amount to the strength of the body. It’s not just our muscles getting bigger that produces strength when we train; rather, it’s also the nervous system’s ability to orchestrate our muscles, to coordinate their action, and to recruit as much force as possible that is also a limiting factor.

A number of laboratory experiments demonstrate that the effects of neural coordination on increasing strength are so profound that simply ‘imagining’ doing an exercise with the same diligence and concentration as actually doing the exercise (no mean feat, I think) can have marked effects on increasing muscular strength. Although different research teams have found the gains in strength to be variable, from nearly as much as physically doing the exercise to significantly less. For example, Ranganathan and colleagues (2004) found strength gains of 35% in a test group that imagined doing little finger abduction and 13.5% strength gains in a group imaging elbow flexion. In contrast, a group that actually performed physical training at finger abduction gained 53% strength.

A classic study (well, classic to me, at least) by Yue and Cole in 1992 found that imagined finger abduction regimens increased the subjects’ strength by an average of 22%; actually doing the same regimen physically that the other test group was doing in their imaginations increased strength by an average of 30%. Enoka (1997) outlines some of the long-term neural consequences of repetitive action patterns, including effects at a wide range of levels (cellular to systemic) and locations (such as in the motor cortex, in the muscles themselves, and in related muscles).

Some of the effects of weight training might be accessible through other techniques. It’s hard to concentrate on your imaginary finger flexes for as long, or as completely, as on finger flexes that you’re actually doing. So weight training might actually be achieving positive benefits, in part, by acting to focus the neural system on the activity and thus create a more efficient control system; but the same effect might be achievable with sufficient concentration without the weight training. In addition, one of the greatest limits on physical strength is the inability to recruit muscles due to pain; weight training might be a way of mitigating perceived pain in the muscles and training the athlete to work in spite of pain. Of course, the danger is that an athlete will actually hurt him- or herself while weight training and have the athletic ability undermined. Simply looking at how athletes perform with weight training and without doesn’t necessarily tell us what the weight training activity accomplishes; it tells us what happens to a whole person put through the activity accomplishes, including significant neural, psychological, perceptual, and other effects that may not be intrinsic to weight training or achievable only through weight training.

The point for me is not to throw out weight training and convince all Olympic-bound athletes to sit around imagining their events. In fact, there are obvious limits; not all strength gain is coming from better neural orchestration of muscles. But neural orchestration, I would argue, is part of all muscular exertion, and overall increases in physical ability are going to require both stronger muscles (including several ways that muscle fibers can become more efficient and powerful) and better neural control over these systems. When you actually see a world-class athlete perform up close — I’m thinking of watching the fast finishers at a marathon a couple of years ago — they don’t move like normal people. There is a breath-taking mechanical and ergonomic efficiency and power in their movements that comes, not only from having bigger and better muscles,and a more resilient cardiovascular system, but also from having a nervous system that is finely adapted to athletic activities.

I bring this up in a post on Neuroanthropology because I think previous incarnations of a person-focused approach in anthropology have been too focused on cognition, emotion, and even similar processes, not focused enough on motor control, perception, and other functions that the nervous system also underwrites. In fact, we know from comparative perspectives that brains aren’t for sittin’ and thinkin’ if you look across species; there’s plenty of animals with brains that don’t do much cogitating, philosophizing, day-dreaming, or even remembering. However, I know of no organism with a nervous system that does not, in some way or another, move.

To put it bluntly, brains are mostly for perceiving and moving, at least if we open our perspective out to the whole range of animals that have them. Yes, humans can do some pretty unusual stuff with our wacky brains, but they do not shed this basic fact because we can do long division, write poetry, or dream up abstractions. Our brains are grown and shaped profoundly by very basic functions; keeping our internal organs functioning together, moving us around, and avoiding, as best our brains can, significant dangers in our environments. So just as the folks talking to Gina Kolata don’t want to give up weight lifting, I don’t think that anthropologists should lose track of the motor, autonomic, and perceptual constituencies in the brain (even though I’m not really talking about perceptual or autonomic in this one).

References

Enoka, R. M. 1997. Neural adaptations with chronic physical activity. Journal of Biomechanics 30(5):447-55.

Ranganathan, Vinoth K., Vlodek Siemionowa, Jing Z. Liu, Vinod Sahgal, Guang H. Yue. 2004. From mental power to muscle power: gaining strength by using the mind. Neuropsychologia 42(7):944-56.

Yue G., and K. J. Cole. 1992. Strength increases from the motor program: comparison of training with maximal voluntary and imagined muscle contractions. Journal of Neurophysiology 67(5): 1114-23.

P.s. Sorry I’m not putting on the Blogging about Refereed Research icons, but I’m traveling in the US for a wedding at the moment and don’t have the code on me.

One thought on “Brainy muscles

  1. Pingback: Months of the Year: Neuroanthropology 2008 « Neuroanthropology

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