The question is: are ripping off sit-ups worth it? Will it make you faster or are they for show? Sure, you might be the envy of your friends and you’ll always have the ‘washboard’ jokes you can let fly, but are they truly making you faster? As always, we’re looking to dissect human movement. Doing so gives us a better understanding of what muscles are firing and in what capacity. The abdominals are a perfect example.
Media sells a six pack as the Holy Grail of fitness. It has become synonymous with speed, health, and overall sexyness. I would like to cordially disagree (at least with the speed and health portion). Exploring anatomy and function we’ll see that the abdominals can function in two ways: top-down or bottom-up. It’s worth noting that they’re multiple muscles that comprise your abdominals, but when we mention it below I’ll be referring to your rectus abdominis.
The majority of people view the abdominals as a crunch machine designed to peel the shoulders from the ground. Does the sit-up motion even look like running? (Please answer no) Research has already proved that sit-ups are damaging to your low back, which should be reason enough to stop, but let’s relate it back to running. As always, we’re looking to train a muscle the way it functions—again the sit-up motion doesn’t mimic a running motion. The only scenario where you fire your abdominals in a top-down fashion is to get into/out of the bed every day. The true function of the abdominals is to control rotation and extension through the spine. We’ll see this in running, too.
Here is the meat and potatoes. The lower fibers of our rectus abdominis control the low back. As we walk, run, and twist, our lower abdominals fire to stabilize the pelvis, indirectly controlling the low back. Remember our articles on core strength? We’ll this is a direct application and expansion on that article. As our foot advances underneath us and progresses to push off, the hip extends and our muscles fire into the ground. The movement applies a force to the pelvis that will attempt to drag it forward. Guess what controls this motion? Yep. Your lower abdominals.
The lower abdominals pull up, checking and controlling forces at push off. Without having great lower abdominal strength you’ll lose stability at push off. You’ll literally be leaking energy with every step. Injuries will range from the low back to the foot and ankle.
Remember, the force is applied to the lower half of your abdominals, not the upper. You’re always looking to match your strength training with the sport. Nailing off sit ups might seem a like a great idea, but you’re not in grade school PE anymore. Actually, you may be accelerating degenerative changes in your spine. Work your lower abdominal strength with dynamic planking and lower-ab specific exercises. Stop the crunches. Stop the madness.