Want a stronger core? Skip the sit-ups

Sit-ups once ruled as the way to tighter abs and a slimmer waistline. Now plank exercises, in which you assume a position and hold it, are the gold standard for working your core, while classic sit-ups and crunches have fallen out of favor.

Why planks over sit-ups?

One reason is that sit-ups are hard on your back. They push your curved spine against the floor and work your hip flexors, the muscles that run from the thighs to the lumbar vertebrae in the lower back. When the hip flexors are too strong or too tight, they tug on the lower spine, which can create lower back discomfort.

In addition, plank exercises recruit a better balance of muscles on the front, sides, and back of the body than sit-ups, which target just a few muscles.

Finally, activities of daily living such as bathing, getting out of bed, or walking, as well as sports and recreational activities, call on your muscles to work together, not in isolation, while sit-ups or crunches strengthen just a few muscle groups. Through dynamic patterns of movement, a good core workout like plank exercises helps strengthen the entire set of core muscles you use every day, leaving you with a stronger and more balanced body.

For more strategies on how to build up your core strength, read Core Exercises, a Special Health Report from Harvard Medical School.

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