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Are Sit Ups Bad for You? The U.S. Military Seems to Think So…

I read an article recently in the Daily Mail about how the U.S. Army is phasing out sit-ups from the Army Physical Fitness Test as well as in their regular training programs. The Marines and Navy may soon be following suit.

So that got me wondering, what’s the deal? Why are these military institutions giving up on one of the long time staples of their physical fitness routines?

The Army is changing its fitness guidelines because it believes sit-ups can be harmful and that there are better ways to condition and strengthen the core.

The Sit-Up vs. The Crunch

The sit-up has had a long reign as the gold standard in assessing and improving abdominal strength, not to mention in achieving a slimmer waistline and the elusive “six pack.”

Then, we had the crunch, which began to unseat the sit-up as the best abdominal move. We learned that the crunch gives more focused contraction potential to the rectus abdominis muscles, while the sit-up puts too much emphasis on the hip flexor muscles.

The transition from sit-up to crunch was positive, but was it enough? Why move at all when working out the core? Next came the static plank.

The Plank

The plank is the latest in improving not just abdominal, but total core strength. A plank is what we call an isometric exercise which means the muscle contracts without any actual movement of the body or lengthening of the muscle.

An isometric plank is used to strengthen and improve endurance and stability in the abdominal muscles, while also including the obliques, gluteus muscles, and the hamstrings. To some extent you even work the shoulders and arms.

There are some variations on the plank, but the most basic form is in a prone position with hands, forearms, and elbows on the floor, toes on the floor, and hips up and in a neutral position with the rest of the upper body. In other words, your body is straight like a plank.

Planks are typically held for a designated time period, such as 30 or 60 seconds at a time, or in shorter time periods with only a few seconds of rest in between, such as 20 second holds with 5 second rest periods.

Why Are Planks So Great?

The U.S. military is making a switch to planks because they have discovered what a lot of trainers already knew:

Planks beat sit-ups every time, in every way.

Planks have been proven both in the gym as well as in the research laboratory to be the most effective way to:

  • incorporate and activate the abdominal and trunk muscles