It's time for another workout challenge, and this one is all about the abs. Perfect for those new to strength training, it's short and sweet — all it takes is a few minutes each day for the next two weeks and you're sure to notice stronger and more defined abs. Instead of doing basic crunches, this challenge involves five crunch variations to target different areas of your midsection.
Here are instructions for the five different variations followed by a 14-day plan to get you all the way to 100. It's not advised to skip right to day 14 (if you want to be able to laugh the next day without rolling over in pain), so follow the plan and adjust it as needed according to your schedule and ability level. Here's printable version  to help keep you on track.
Related: Try Our 30-Day Squat Challenge 
- Lie on your back, and lift your legs and arms up so they are extended toward the ceiling. Lift your upper back off the floor, reaching your hands toward your feet.
- Lower your legs toward the floor while reaching your arms overhead, keeping your shoulders off the mat and lower back pressed into the mat.
- Repeat the crunch motion to complete one rep.
- Start on your back with your elbows resting on the floor at a 90-degree angle.
- With your core engaged, roll up to almost sitting while bringing your right knee up to meet your left elbow. It should feel a little like running.
- With control, straighten your leg as your slowly peel your back down, vertebra by vertebra, until your shoulders touch the mat last.
- Alternate with your other leg to complete one rep.
- Lying on your back, lift your legs in the air with your knees bent. Place your hands on the floor beside you.
- Without momentum, use your lower abs to slowly curl the hips off the floor and into your chest. Slowly lower them back to the starting position.
- This counts as one rep.
- Lie on your back and open your legs into a diamond shape (aka butterfly legs), with the soles of your feet pressed together and knees out wide. Extend the arms overhead.
- Inhale to curl the torso up, and tap the floor in front of your feet to stretch your glutes a bit.
- Slowly lower back to the starting position.
- This counts as one rep.
Technically considered a sit-up, this effective move works the abs through a larger range of motion and adds some functional fitness training to the challenge.
- Lie flat on the floor with your lower back pressed to the ground.
- With your hands behind your head, bring your knees toward your chest and lift your upper back until your shoulder blades off the mat. Be sure not to pull on your neck.
- Straighten your right leg out to about a 45-degree angle to the ground while turning your upper body to the left, bringing your right elbow toward the left knee. Make sure your rib cage is moving and not just your elbows.
- Switch sides, and do the same motion on the other side to complete one rep.
End by doing Sphinx pose  to stretch out the abs.