Perform each exercise for 20 reps each with little to no rest

Straight Leg Sit-Up
Tip: Keep the arms reaching for the ceiling the whole time

Regression: No weight; traditional situp; classic crunch

Double Crunch
Tip: Bring the elbows to the knees. Extended position is a hollow body hold.

Regression: No weight

Leg Lowers
Tip: Try to keep legs as straight as possible with lower back pressed into the mat.

Regression: No weight