Friday, 19 October 2012

Injury, Weight Loss and Pure Speculation


Nearly every female runner I know who has tried to maintain a low body weight has ended up with overuse injuries—myself included.

I have a very strong body. My bone mineral density is high for a woman of my age despite the fact that I have been on inhaled corticosteroids for my asthma (but not so high as to make my bones brittle).  On minimal training, I can go out and run incredibly long distances. My body doesn't fall apart; I don't take time off due to injury. I've only had one major injury in the last five years, and that was when I came off my 50 cc scooter at over 50 km/h and skidded across the road with my foot trapped under the bike. I fractured my fifth metatarsal. It healed up perfectly and hasn't been a problem since.

But I wasn't always so strong. When I was competing in triathlon, training 22 hours per week, I used to supplement my diet by drinking a meal replacement shake between breakfast and lunch, and another between lunch and dinner… and sometimes a third one before bed. I couldn't eat enough to keep the weight on, and if my weight fell below 60 kg I got injured, every time. Knee inflammation. Muscle tears. Overuse injuries. Shin splints, even when my form seemed excellent. If I had drawn a chart plotting my days spent injured against my weight, you would've seen the most amazing thing happening around 60 kg: on one side, many days injured, on the other, very few.

My case is not the only one, and it's not a scenario that's exclusive to ultra running. It's well documented—look up Female Athlete Triad (with the unfortunate acronym FAT). Yet despite the many studies conclusively showing that there is such a thing as being too light, the unhealthy myth of 'lighter is faster' persists in our sport. It's a myth that is perpetuated at races where relatively chubby runners like me rarely place highly. (Note: I said relatively. I don't think I'm chubby, but I am much larger than most of the podium finishers.) Perhaps lighter is faster, but I'm almost certain that longevity carries a little more weight. Have a look at runners that keep performing moderately well for a very long time in the sport. We're not skinny, but we're still here.

Does low weight cause injury? I'm not sure. Low body weight generally means you're burning a lot more energy than you're ingesting. So it's also plausible that you're going through more essential nutrients than you're consuming. This may directly upset your body's functioning, such as low iron reducing the oxygen carrying capacity of your blood. It may also have a less direct effect. For example, if there's not enough calcium in the muscles to sustain contraction, it starts leaching out of your bones. Hello, stress fractures. But it's also possible that low body weight or low body fat are not the cause of an increased risk of injury but rather that they are both effects of some other underlying cause. A diagnosable example of this could be coeliac disease; who knows what other diseases are yet to be discovered?

Influenza and a few long races had left me alarmingly thin by the time I fronted up to Caboolture in July. My appearance drew comments: I was described as looking great, really fit, no fat on me, stronger and faster than ever, and so on. To me, I was way too skinny. I felt I was putting myself at great risk by racing when my weight was below 61 kg and dangerously close to that 60 kg mark. I held together, though, and afterwards I was at great pains to put the weight back on before I raced again.

I'm not going to try to convince everyone that we need to get heavier, that light women won't run faster and win more races. We can only do what we think is right for ourselves. But I urge you to be really honest with yourself. Ask yourself why you have to be a certain weight to run fast. Where did you get the number from… was it a Facebook quiz? Did you model yourself off someone else? And finally: do you track your weight and your injuries? Do you notice a correlation?