Just before moving to our new home here on Scienceblogs, I asked our readers for ideas on what types of content they would like to see here on Obesity Panacea. One topic that came up several times was the issue of injuries. I’m not sure why we haven’t discussed injuries in the past (aside from the fact that it’s not the focus of our research), but it was a great idea, and I’ve come across a study on the topic that I think will be of real interest.
The study is titled “The influence of exercise and BMI on injuries and illnesses in overweight and obese individuals: a randomized control trial” and was performed by Carol Janney and John Jakicic at the University of Pittsburgh. Participants in the study included overweight and obese individuals taking part in one of two exercise studies – one focused weight loss and the other on weight maintenance. The exercise component of the two studies were similar, with participants walking at a brisk pace 5 days/week (the major difference between the two studies is that one included caloric restriction to induce weight loss, while the other simply emphasized healthy eating patterns). Every 6 months, participants reported any injuries or illnesses that impacted their ability to exercise.
During the 18-month interventions, 32% of all participants reported having an injury which impacted their exercise regime. Not surprisingly, the most common injuries were in the lower body (suffered by 21% of participants) and the lower back (suffered by 10% of participants). Of the lower body injuries, the most common issues were knee injuries, sprains, tendinitis, hip injuries, and “general muscle muscular injuries”. What I find particularly interesting is that of those who experienced an injury, 59% said that it had nothing to do with their exercise participation. In other words, these individuals felt that those injuries would have happened whether or not they were exercising. In contrast, just 7% of injured individuals felt that their injuries were due entirely to their exercise program. And most interesting of all? The rate of injury did not differ between the experimental and control groups! So individuals involved in the exercise programs were at no greater risk of injury than their sedentary peers. What’s more, injuries lasted for a significantly greater duration in control participants, in comparison to individuals in the exercise groups. Training volume appeared to have little to no impact on injury risk, while BMI had a strong influence on the risk of injury or illness – the greater an individual’s BMI, the greater their risk. In fact, the risk of injury increased by roughly 8% for each 1-unit increase in BMI whether the individual was performing exercise or not.
What’s the take-home message?
This study suggests that in overweight and obese individuals, exercise (in the form of walking) has little or no association with injury or illness. In fact, it suggests that excess body weight poses a far greater injury-risk than exercise itself. That is extremely important, as I have met many individuals who do not exercise specifically because they are worried about injuring themselves, especially an injury to their lower body. Now it should be noted that the exercise employed in this study was brisk walking – we’re not talking about intense Biggest Loser style bootcamps. But brisk walking is exactly the type of exercise that it advocated for this population, so I think that the results are quite promising. It also underscores the important impact that body weight can have on the musculoskeletal system (one of the only instances where BMI is as good as advertised!), and suggests that anyone working with overweight or obese individuals should pay especially close attention to injuries, especially in the lower body.
I should mention that the paper I’ve discussed today is free to anyone with an internet connection via the nice folks at Pubmed Central. It’s a very well written and readable study, so I’d strongly recommend you check it out for yourselves.
Injury prevention is an important topic, and one that I plan to revisit in the future. Issues having to deal with flexibility and over-use injuries like shin splints and plantar fasciitis affect people of all shapes and sizes, and I’m looking forward to discussing them in detail. In the meantime, just remember that for obese individuals, being sedentary poses as much risk of injury as being physically active – one more reason to start moving!
Janney, C., & Jakicic, J. (2010). The influence of exercise and BMI on injuries and illnesses in overweight and obese adults: a randomized control trial International Journal of Behavioral Nutrition and Physical Activity, 7 (1) DOI: 10.1186/1479-5868-7-1