Grunting

Breaking news, scientists discover grunting.

Well, something like that anyway. For many years (at least as far back as Jimmy Connors) there has been debate in the tennis world about players who grunt and those who are distracted by it and want to forbid it.

It was shown recently that grunting does in fact have a positive effect on performance. link

To summarize, various study participants had a 1% - 5% performance boost if they grunted during weighlifting. And some rather colorful speculation as to why this works (or doesn't):
1. "Grunting quiets inhibitory nerves cells in the spinal cord. Those cells would normally impede the ability of muscles to contract and generate force."
2. "It's a psychological thing. But psychology is very important in sports in general -- if you think you can, it raises the possibility that you can."
3. "Some people grunt to give others the impression that [the grunters] are doing a lot of work. It's just like flexing and strutting, trying to attract attention."
4. "They're not breathing properly. In order to grunt, they have to hold their breath and exhale forcefully."

I have a confession. I used to not be a grunter, but I found one day that I had become one. I play soccer with college students half my age, and when I
need a burst of acceleration, I grunt loudly and instinctively. Once I realized I was doing that, the reason became clear, at least to me. I needed to force blood/oxygen into my leg muscles. The grunt does this by increasing blood pressure.

Now if only I can figure out why I yawn...