Why We Grunt At The Gym

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Mid-grunt.

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Grunting, the loud, sometimes obnoxious, noise typically produced when we exercise, has been an ongoing source of debate among psychologists. 

From a purely scientific standpoint, the grunting noise is made as we "exhale against a closed, or partially, vocal fold," said Dennis O'Connell, a professor of physical therapy at Holland School of Sciences & Mathematics in Texas.

The vocal folds, or vocal chords, refer to two bands of muscle tissue that open into the windpipe. The vocal folds are open and relaxed when we breath in, sometimes producing a rushing noise. But when the vocal folds close, as we exhale, "you are going to hear some turbulence," said O'Connell.

The reason we grunt is slightly more complicated — some experts say it improves performance, others say it's just blowing smoke.  

Belisa Vranich, a psychologist at willspace, a boutique training studio in New York City, is of the camp that believes grunting is a natural — and necessary— physical response to exerting effort.

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"Think about tennis — when you hit the ball it's hard to be explosive and not grunt," she said. And if you're not grunting, you should be because it gives the gives the gruntee more power: "It helps you push more weight, hit harder, and throw farther."
When we do something like squats or power lifting, we take air in and hold our breath for a moment. By doing that, we squish the middle of our body together and create a pressure ball in our belly that makes our body rigid in order to stabilize and protect our spine from injury, says Vranich.
All that pressure built up inside our gut means that when we finally do exhale, "it's almost impossible to let that energy out without making a grunt," said Vranich.
Scientists don't know exactly why a sharp yell or grunt gives individuals that extra "oomph" when they pump iron or swat at a tennis ball, for example, but it's probably related to a communication signal from the part of the part of the brain that controls breathing to the part that controls muscle function, says O'Connell.
When we forcefully push air out, the brain sends information down to the muscles, which either excites muscle groups, decreases inhibition, or does both. The result is enhanced performance.
This beneficial effect of grunting was demonstrated in a study of college tennis players, where O'Connell's students found that grunting increased serve and forehand velocity by an average 4.5 mph. It didn't mater if the players were regular grunters, if they were male or female, or how they felt about grunting.
Although grunting seems like like natural thing to do, Vranich admits that unnecessary or excessive grunting is annoying. That kind of testosterone-pumped, animalistic sound designed to psych the individual up and get adrenaline going, or even intimidate a competitor, is rooted more in psychology than physiology.

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The controversy over whether grunting should be allowed or discouraged is growing, particularly at the gym or on the tennis court where it can be distracting during competition.

In 2006, a bodybuilder and correction officer was kicked out of a Planet Fitness for grunting, which violated the club's strict "no-grunting policy." Shortly after that incident, a man was attacked at an Equinox gym in New York City for being too noisy in spin class. 

O'Connell recognizes that grunting maximizes force production. He also believes that all the hooting and hollering can be controlled, and that there are more silent breathing techniques for achieving comparable muscle activity and peak force. 

A recent study from O'Connell's department found that in a simulated forehand stroke, athletes got the same power boost from grunting as they did just by forcefully expelling air. 

"Forced exhalation without the annoying sound is just as good at increasing force production as exhaling with the annoying sound," said O'Connell. 

The professor relayed an anecdote from his daughter's softball games, when he would overhear dads telling their kids to grunt. If you can be coached to grunt, then you could certainly be coached to exhale without grunting.