bicycle crunches

How bicycle crunches hurt core rehabilitation

If you’ve ever set foot in a gym, you’ve probably witnessed the bicycle crunches. Also referred to as the cross-over crunch, this popular exercise involves drawing the elbow to the opposite knee while crunching the abs and rounding the spine. You might have even performed these yourself! I know I did… that was before I learned that bicycle crunches both cause and worsen diastasis recti, the medical term for abdominal separation.

What’s wrong with bicycle crunches?

Bicycle crunches are essentially a double-whammy for your abs – and I don’t mean that in a positive sense.  Although they do strengthen some of your abdominal muscles, bicycle crunches are a total disaster for your abdominal wall and actually weaken the middle of your abs. They place excessive strain on the linea alba, the connective tissue that runs along your midline. Over time, this repetitive stress can separate your abdominal muscles, widen your waistline and create a pooch (for men as well as women).  Yes, even men may be affected by diastasis recti!

Whammy #1

The crunch element of a bicycle crunch bulges the abdominal wall forcefully forward, weakening the very center of your abdominal muscles and compromising the connective tissue that runs up and down the center of your rectus abdominis, your 6-pack muscles (whether or not it’s visible, we all have a 6-pack under there somewhere). When performed repeatedly, this forward bulging pressure forces the muscles to spread apart, causing diastasis recti.

Whammy #2

The cross-over element of a bicycle crunch further separates the abs directly at the belly button, the most vulnerable point in the abdominal wall. This is caused by a shearing action of the obliques that occurs when you combine twisting with forward flexion of the spine.

So bicycle crunches not only bulge the abs forward, weakening the center of your rectus abdominis and stretching the connective tissue sideways, but they also splay your abs apart diagonally at the umbilicus (the belly button). Given the obvious drawbacks and potential for diastasis recti, it makes sense to replace the bicycle crunch with an exercise that safely achieves all of your training objectives without inflicting collateral damage.

The healthy alternative: waist cincher with twist* (pictured above)

To strengthen and tone all layers of abdominal muscles both safely and effectively, I recommend waist cincher with twist as an alternative to bicycle crunches in your personal workout regimen. This exercise safely strengthens the obliques to narrow your waist as it effectively engages both the rectus abdominis (your 6-pack muscles) and the transverse abdominis (your natural corset) to flatten and firm your abs.

Begin by lying on your back with your knees bent (remember to get down sexy!) Then drop both knees to one side while keeping your shoulders square to the ceiling. This positions you in a spinal twist. Place one hand on your abs, directly over the belly button. Tuck the other hand under your head to support the neck. Prepare by taking a small breath. Then exhale and draw your belly button flat to the spine as you nod your head “yes.” Be sure to draw the chin gently toward the chest as you nod – it’s a tiny movement. The shoulders stay in contact with the mat throughout the entire range of motion. Inhale as you return your head to the starting position and soften the abs.

Perform slow, controlled repetitions for 2 minutes. Then switch your knees to the opposite side and perform a second set for 2 minutes. With each pulsing repetition, flatten your abs toward the spine as you exhale and nod “yes.”

Say “yes” to training smart for firm, flat abs and a sexy waistline. Use science, not just sweat. For video instruction on this exercise, please see disc 5 “Toned Arms & Tiny Waist” in the postnatal 10 Minutes Flat series.

*Note: Waist cincher with twist is appropriate for general fitness and postnatal recovery. Please do not perform this exercise during pregnancy.

By Leah Keller, Creator of The Dia Method. Learn more about Leah at