Pushing the limits of your athletic potential requires, as the author John L. Parker, Jr., once put it, “a certain amount of time spent precisely on the Red Line, where you can lean over the manicured putting green at the edge of the precipice and see exactly nothing.” Balancing on that edge is tricky, and it’s why top athletes get injured pretty frequently, having pushed just a little too far. Of course, some athletes get injured more than others. Is that just a matter of luck and biomechanics—or is there some degree of skill in managing the delicate balance between enough and too much?
That’s the question at the heart of a new study from researchers at the University Medical Centre Groningen in the Netherlands, published in the Scandinavian Journal of Medicine and Science in Sports. A group of 73 tennis players in the country’s national high performance program, all between the ages of 11 and 14, completed a series of psychological tests at the beginning of the season, and were then tracked weekly for the rest of the year to see who got injured and how severely.
The researchers hypothesized that self-regulatory skills would help distinguish who got injured and who stayed healthy. In particular, they focused on four “meta-cognitive”—which means thinking about thinking, basically—elements of self-regulation: planning (“I determine how to solve a problem before I begin”); self-monitoring (“I keep track of my progress”); evaluation (“I go back and check my work”); and reflection (“I often reappraise my experiences so I can learn from them”). In essence, the idea is that knowing which pains you can train through and which require some time off is a skill that requires careful and honest self-appraisal, and that you can get better at if you’re sufficiently reflective.
The results were pretty stark. During the season, the 73 players suffered a total of 88 overuse injuries, not including acute injuries and illnesses. For the most part, they were pretty good at self-regulation: 28 of them score highly on planning, 36 on self-monitoring, 48 on evaluation, and 43 on reflection. But the players with moderate or low overall self-monitoring scores were 4.6 times more likely to suffer an overuse injury that required missing training or competition compared to those with high self-monitoring skills. That’s a huge difference.
There was an additional wrinkle when they broke the results down by gender. Among the 45 boys in the study, self-regulatory skills didn’t actually have a significant relationship to injury risk. Among the 38 girls, on the other hand, those with moderate or low self-regulation were a whopping 10.8 times more likely to lose time to overuse injuries. It’s worth looking a little more closely at that finding.
As it happens, the new study is actually a follow-up to a 2017 paper in the same journal, where the authors analyzed the same dataset looking for links between risk-taking behavior and injuries. In that case, the results were the mirror image of the self-regulation data. Risk-taking, as assessed by a card-based betting game called the Iowa Gambling Task, was associated with increased risk of losing time to overuse injuries in the boys, but not the girls.
It’s tempting to combine these results into some sort of pseudo-evolutionary narrative about how the psychological traits that made males good hunters long ago now make them prone to tennis elbow, and how women evolved to ignore discomfort because of childbirth or whatever. Let’s resist that temptation. In a small study like this, it’s hard to know whether the gender-based differences they observe are generalizable differences, or simply reflect the particular characteristics of the 45 boys and 38 girls in the study. For example, the average international ranking for the boys was 436, compared to 281 for the girls—so maybe competitive level, or some other factor, is the real source of these differences.
Still, the overall data suggests that psychological traits do affect how likely you are to get injured, joining previous studies like the one I wrote about last year that found runners with perfectionist tendencies were 17 times more likely to miss training time with injuries. While this area of research is still in its infancy, it’s hard not to wonder what you can actually do about it. There’s plenty of research about how to improve self-regulation in the context of eating habits, and even about teaching pre-schoolers better self-regulation through mindfulness-based training. I don’t know how much of this we can apply to sports injuries, but I’m sure there are people working on it.
The authors of the study suggest that coaches and trainers should be on the lookout for athletes with weak self-monitoring skills, and try to help hold them back when necessary. This seems reasonable. But maybe the bigger point is simply that overuse injuries are not acts of god. They flow, at least in part, from the choices we make. For an athlete who is training hard, those choices are difficult. You’re always gambling, trying to guess which aches you can safely ignore and how much fitness you can afford to lose. And you’ll inevitably guess wrong some of the time. But if you don’t gradually get better at that guessing game, perhaps you’re simply not paying close enough attention.
My new book, Endure: Mind, Body, and the Curiously Elastic Limits of Human Performance, with a foreword by Malcolm Gladwell, is now available. For more, join me on Twitter and Facebook, and sign up for the Sweat Science email newsletter.