From weightlifting and martial arts to opening a particularly tight pickle jar, when people attempt full exertion, the “grunt” is soon to follow.  If you’re ever exercising in close proximity to a vigorous grunter you’ve probably wondered if this ritual is all together necessary.

The short answer is “yes”.  Well maybe.  They may just be obnoxious.  I used to warm-up next to a man who would growl and caterwaul through hip rotations like a grizzly bear going through back labor.  The grunt is not purely bluster though.  If that weight room grunter is involved in a movement requiring optimal spinal stability, then that grunt is a valuable tool to prolong peak respiratory muscle contraction and stiffening of the spine.

In 2008 Wang and McGill studied the relationship between the muscles involved in respiration and their impact on spinal erector muscle recruitment.  This study was published in Journal of Applied Biomechanics in 2008.  This study of eight asymptomatic males without back pain revealed several interesting trends in the relationship between ventilation and spinal stability.

• With full inhalation the spinal stability increases
• The stability reaches to a maximum when the abdominal wall tightens to force air out of the lungs.  The GRUNT occurs when you initiate the exhalation then quickly catch the breath and maintain peak spinal support of the respiratory muscles.  It’s a clever and intuitive trick.
• That spinal stability decreases as air continues to leave the lungs
• Some individuals lose enough stiffness during the exhalation phase to compromise stability and are most vulnerable to injury during this phase of the ventilation cycle

Here are a couple practical applications:

 

1)  If you or one of your athletes loses spinal stability during metcons, check if it is due to poor stabilizing motor patterns by placing the hands on the lateral abdomen above the iliac crests and checking for an ON/OFF pattern of the abdominal tone.

 

2)  Attempt a challenging lower back stability move such as a one arm pushup or strict barrel roll during the exhalation phase.  Try again while holding a deep inhalation and push into it.  Go ahead and make some noise.  If you notice a performance difference, use it when you need it.