Reverse crunches target the lower abs and tone the lower belly pooch by working the rectus abdominis, transverse abdominis and obliques without neck or back pain.

“In a crunch, you give the abdominal muscles ... while still working on multiple muscles. For example, a plank with a knee lift toward the opposite side of the chest increases ab activation ...

The trainer suggests starting with easier versions like partial crunches (lifting the shoulders a little off the ground) or bent-knee crunches ... core exercises, like planks or pelvic tilts ...

The Bottom Line: Ditch the sit-ups. These bodyweight exercises are smarter, tougher, and deliver more bang for your buck.

"From a side plank, lift your top leg and arm into a starfish position. Hold or pulse," Willis suggests. "In a forearm plank, slide a mini band across the floor underneath you, from hand to hand. Keep ...

Examples include the plank and knee-to-chest stretches. Stretching the back muscles after completing a back-strengthening routine can help prevent muscle soreness and injury. It may also provide ...

Our volunteers did this 4 times per week – alternating days. Following a single plank set to warm up, held for 20-30 seconds, the group completed 3 sets of each of the 6 main exercises.