The “Core” is not just a dumb stiff box—like a Turtle’s shell—between your arms and legs. Evolutionary Biology and evidenced-based Science reveal that the Core is comprised of the most intelligent and powerful group of obliquely arranged rotational muscles in your body. That’s why we call it the Core Engine! It’s nearly half of your total muscle mass that you can’t live, or move, without.
Practicing “core-stability” exercises literally kills your core by teaching it to be stiff and rigor mortised. While planks and poses are great preparation for being in a casket, we believe Life-time should be spent working on dynamic mobility and 3-Dimensional strength. This is why we train—at different speeds and loads– the Core Engine in every rep of every exercise.
Core Engine rotation is why humans can throw, strike, and swim (freestyle is ~8% faster than butterfly) more powerfully WITH ONE ARM, than both arms same-time.
As you can see in the images below, the vast majority of our mid-section muscle fibers are arranged obliquely— not “vertically”—because the Core Engine is specifically designed to produce, transfer, and manage rotational power; THE CORE IS NOT DESIGNED TO BE STIFF &”STABLE” LIKE A TURTLE’S SHELL!!!
The World’s foremost expert on Spine Biomechanics, Dr. Stuart McGill has gone on the record saying “planks for more than 10 seconds are a waste of time…And probably detrimental to other aspects of human performance..” Need one more reason to not waste time practicing being stable/stiff? NASA abandoned isometric exercises for astronauts because they didn’t prevent muscle wasting.
Like all things physical, the Core Engine is use it, or lose it.