Grunting may be frowned upon at the gym or result in warnings or disqualifications in professional tennis, but according to research led by Bryant’s Jason Sawyer, Ph.D., the low, short guttural sound is an easy and cost-effective way to increase power output during explosive movements. Recently published in the Scientific Journal of Sport and Performance, Sawyer and outside researchers sought to determine the effects of grunting on muscular power output, including striking and jumping, in martial arts.
“I am an avid martial artist, participating in Krav Maga and Brazilian Jiu-Jitsu, so this topic was personal to me,” says Sawyer, Bryant’s Exercise and Movement Science program coordinator and professor who works out of the School of Health and Behavioral Sciences.
Sawyer explains that muscular power is critical for athletic competitions, and, as levels of competition increase, the disparity between winning and subsequent positions decreases. This result, therefore, prompts athletes and coaches to make small performance tweaks — some of those popular choices being nutritional supplementation, varying exercise programs, footwear, and equipment modification — to give them an advantage over their opponents.
For this study, researchers recruited 24 subjects from a local martial arts academy. Each study participant, ranging from ages 19 to 52, was required to have a minimum of two years of martial arts experience and must have attended martial arts classes at least twice per week. Performance measures included five maximal cross punches and roundhouse kicks to determine peak power output as well as three countermovement vertical jumps and seated landmine throws. Study participants performed these tests under three breathing conditions: held breath, audible exhale, and grunting.
RELATED ARTICLE: Looking to reduce depressive symptoms? Resistance training could be the answer
Findings showed a statistical difference between grunting and both the held breath and audible exhale conditions. Grunting increased power output for the cross punches and roundhouse kicks but had no effect on power output during the vertical jumps and seated landmine throws. He notes that, given the results, it’s possible that grunting increases corticospinal excitability, which leads to greater force production during certain exercises. Additionally, grunting seemed to be more effective at increasing power output during activities that required kinetic linking between upper and lower extremities.
“The most interesting findings were the magnitude of the effect that grunting had on performance. We expected a small increase in performance when grunting; however, the large increase in power output was surprising,” Sawyer says.
For future studies, researchers recommend investigating the effects of grunting on electromyography (EMG) activity of the abdominal musculature while striking. Additionally, ground reaction forces could be measured while grunting during striking, and studies could also look at determining if grunting increases corticospinal excitability more than a forceful exhale.
