Crunches are another enduring bodyweight exercise ... or the other or lifting your feet into the air as you slowly bicycle kick to perform an exercise known as bicycle crunches.

Mix and match for 30-second holds, and feel the full-core power kick in. Bicycle crunches give your abs and obliques a ...

No matter which variations you follow, crunches have the advantage over sit-ups of being able to better target abdominal muscles. "Because the movement is smaller, you can control momentum more," ...