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," ...

Lifting your head and shoulders to one side or the other or engaging in bicycle crunches by involving your legs will, too. These and other variations like ones involving free weights or resistance ...

Just 10 minutes of training left my abs aching for days, and if you want an effective workout to target the whole core, this ...

On some exercises I was comfortable that I could do a full 45 seconds of work, like mountain climbers, but I found hitting that mark a bit trickier with moves like the bicycle crunch, so I dropped ...

You'll need to be comfortable with roll-overs, scissors and jack-knives before attempting this variation ... Similar to a classic bicycle crunch, but slower and more controlled.

Try variations like side planks ... then switch sides in a pedaling motion. Why it works: Bicycle crunches engage both the upper and lower abs while also working the obliques. How to do it: Kneel on ...

Plank variations are also amazing for working out multiple core muscles at the same time. Begin with a simple plank by ...