Researchers quantify cycling’s mind-body debate
Yogi Berra, who claimed he never said most of the things he said, supposedly assumed that baseball was 90% mental and the other half physical. This is the kind of math you get into when you start trying to apportion credit for sports wins and blame for losses. It is an unanswered question.
But we still like to ask, as I discovered after writing a book claiming that endurance, a seemingly simple physical parameter, is influenced by the brain. Almost every interview I did after it was posted included some version of this question: OK, so the brain matters… but how much, exactly? I have become an expert at dodging the question and covering my answers. (“Well, that really depends on the context…which reminds me of a great but unrelated anecdote.”)
But not anymore. Thanks to a new study in the European Journal of Sports Science, from a research team from the Swiss Federal Institute of Sport led by Phillip Röthlin, I can finally provide some numbers. The study involved 25 members (17 boys, 8 girls) of the Swiss national under-17 cycling team. They did a series of physiological and psychological tests, then ran a time trial up a mountain. Paste the results into a statistics program and you’ll have an answer as to the relative importance of various traits and parameters in sports performance.
The physiological side was represented by a VO2 max test, which is the gold standard measure of aerobic fitness and quantifies how quickly your heart and lungs can deliver oxygen for your muscles to use. As befits elite teenage cyclists, the values were impressive, with an average of 63ml/kg/min for women and 71ml/kg/min for men – not quite “world class”, but certainly “highly trained” and perhaps in some cases “elite.”
Previous studies have shown that VO2 max is a good predictor of performance: a 2010 study, for example, found that it explained 81.3% of the variation in ten-mile running times among well-trained runners. . There are, however, two caveats.
The first is that this number depends on who the population is. Catch random volunteers on the street and you’ll find that VO2 max is an amazing predictor of running performance. On the other hand, sample the runners-up in an Olympic race and you’ll find that it’s not very good at predicting the order of finish. Everyone in the Olympic realm needed to have a stratospheric VO2 max just to get to the start line, so other factors play a bigger role in differentiating them.
The other caveat is that it depends on the parameters you include in your template. The 2010 study compared VO2 max to other physiological parameters like running economy and lactate threshold, and surpassed them. (An even better predictor was found to be runners’ speed at the end of the VO2 max test, which is a hybrid measure of VO2 max and running economy.) But no psychological parameters were included , so the claim that VO2 max explains 81.3% of running performance is based on the assumption that the brain doesn’t matter at all.
The main objective of the Swiss study was to conduct this type of study including both mental and physical characteristics. They measured five different psychological factors in athletes:
- Mental Techniques: the use of self-talk, imagery, goal setting, activation (i.e. excitement) and relaxation
- Self-compassion: manage personal mistakes and weaknesses without harsh self-criticism
- Strong minded: perseverance, bouncing back from failure, performing well even in difficult conditions
- Motivation for success: a need for success and the search for excellence
- Action and state orientation: whether you refocus quickly after mistakes or failures (action orientation), or tend to dwell on them (state orientation)
Each of these parameters was assessed using psychological questionnaires and quantified on scales of one to five or one to seven.
The time trial was a relatively short climb of 1,320 meters (just over three-quarters of a mile), rising to 1,800 feet. The uphill stroke was chosen to eliminate the effects of air resistance and drafting. Distance is another important caveat to keep in mind, as the relative contributions of mind and muscle likely differ over time. My best guess is that the mental factors become more and more important as the distance gets longer, but I have no supporting data!
The results are expressed in terms of “standardized regression coefficients”, which essentially tell you the relative size of the effect. The biggest predictor, unsurprisingly, was VO2 max, which had a coefficient of 0.48. In mathematical terms, if you improve your VO2 max by one standard deviation, you would expect your race time to improve by 0.48 standard deviations.
This may sound a bit abstract, but it’s a bit clearer when you compare different factors. The strongest psychological predictor was persistence, a characteristic that relates to achievement motivation. For example, people who agree with the statement “I find it difficult to sustain my efforts in sport over a long period of time” would be considered to have low persistence. Persistence had a coefficient of 0.11, which means that its influence was about a quarter (i.e. 0.11/0.48) as strong as VO2 max, which is still a highly significant result. .
On the other hand, people who reported using mental relaxation techniques actually realized worse in the time trial. The effect was very small, with a coefficient of 0.03 indicating that VO2 max was 16 times better at predicting performance. And more specifically, this is where the drawbacks of looking at correlation rather than causation (which would require a trial in which participants were randomly assigned to use mental relaxation techniques or not) become apparent. It seems likely that this result was a statistical fluke or that the weaker or more anxious athletes were the ones telling themselves to calm down before the start.
And that’s all. Other than gender (men were, on average, faster than women), none of the other predictors were statistically significant. So the final tally is that the physiological factor, VO2 max, has 3.4 times more explanatory power than the two psychological factors, which could mean that short uphill cycling races in near-elite adolescents are at 77% physical and 23% mental.
I hope you don’t take it at face value, of course. Not only is it completely context specific, but it also depends on which variables you include or exclude. Maybe there are other physical parameters, like leg strength or cycling economy, that matter a lot in uphill short-cycle racing. And I can also guarantee that we don’t yet know how to properly quantify the various mental parameters that could affect the results. But take this as proof of principle: if you want to know who’s going to win a race, a simple paper-and-pencil psychological test will give you information you can’t get in the lab – just like Yogi said, more or less less.
For more sweat science, join me on Twitter and Facebook, sign up for the email newsletter and check out my book Enduring: Mind, Body, and the Curiously Elastic Limits of Human Performance.