Take The Fall Out Of Exercise
Sydney Morning Herald
Thursday August 19, 2004
Feel clumsy post workout? It's all in the head, writes Emma Young.
If you find yourself staggering as you head home after a strenuous run or gym session, the problem isn't in your weary muscles - it's in your brain.It's long been known that exercise can lead to clumsiness. "It becomes harder to perform skilled movements," says Professor Uwe Proske, of the department of physiology at Monash University in Melbourne. "For example, after a lot of hard work in the garden, if you then tried to thread a needle, you would have considerable difficulty." Scientists had thought damage to minute sense organs in fatigued muscles was to blame. But Proske's team found this was not the case. "We did some experiments and showed pretty conclusively that after the sort of exercise that damages muscle fibres, these muscle sense organs were perfectly normal." To investigate further, Proske blindfolded volunteers and asked them to stretch out their arms, holding them both at identical angles to their body. This was easy. But then they exercised just one arm by lifting a two-kilogram weight until their muscles felt exhausted, and were asked to repeat the task."And then they made big errors," Proske says. Even though the volunteers insisted their arms were aligned, they were not. The conclusion from all this is that the brain works out where the limbs are in space partly by using information it collects on how much effort against gravity it takes to move an arm or a leg into a particular position. If your limb muscles are tired, that limb is harder to move - and this confuses the brain. The confusion, and resulting clumsiness, vanishes as your muscle fibres are repaired. In the Melbourne study, the volunteers showed detectable problems for a week after the weight-lifting exercise. For people who rely on perfect physical co-ordination, this might cause problems. It's possible that limited exercise, such as a bit of gardening, might worsen the performance of an Olympic shooter, or hurdler, Proske suggests. "This is pure speculation, but it could perhaps make them more likely to stumble," he says.
© 2004 Sydney Morning Herald