The 10 Best Ab Exercises to Strengthen Your Core

Criss-cross is one of Joseph Pilates' (founder of Pilates) original mat exercises. Like the traditional bicycle crunch
, it similarly targets the obliques. However, the main difference is the emphasis on keeping elbows wide to increase rotation. "Rotation is an important function in our everyday lives," Brandenburg says and this exercise offers a practical and effective way to target rotational strength.

1. Start in a Pilates curl; hands behind head, elbows wide and legs in tabletop.
2. Extend your left leg to 45° and rotate your left elbow towards your right thigh.
3. Rotate to the opposite elbow and thigh.
   Continue this pattern with your elbows wide, maintaining a curl in the upper body.
4. Repeat for 10 reps (right to left) 3 times.