High-Rep Core

Try this core workout to really help tone the abdominals. It incorporates high reps with just bodyweight for the exercises. The most important part of this workout is the pace at which it is performed. The "rest" periods are the sets of planks in between the other exercises. By keeping your heart rate up, you'll burn more calories and tone the core while improving your overall endurance.

1. Crunches - 30 reps
   1. Start on your back with your feet on the ground, knees bent at 45 degrees, and hand behind your neck. DON'T pull on your neck with your hands.
2. Bicycle Crunches - 30 reps (15 each leg)
   1. fter the 30th rep of the regular crunches, bring one knee towards the opposite elbow (keeping your hands behind your head). Release the leg back down to the ground and allow your core to relax while your back returns to the ground. Repeat with the opposite knee to the opposite elbow. Your legs will make a "bicycle-like" movement, hence the name.
3. lank - 30 seconds
   1. eep your core and upper back tight while remaining in a straight line from toes to head.
4. traight-leg Sit-ups - 30 reps
   1. tart laying flat on your back, legs extended out together with your hands to your sides. Keeping your legs touching the ground, sit straight up such that you end sitting up (legs still stretched out in front of you). Release your back slowly to the ground. 
      1. Note: it may be hard to keep your legs touching the ground at first (especially without some weight on your toes), but the goal is to keep them touching as much as possible. As your core strengthens you'll get better at this.
5. Oblique Crunches - 60 reps (30 reps each side)
   1. Start on your back with your feet on the ground, knees bent at 45 degrees, and hand behind your neck. DON'T pull on your neck with your hands. Drop both legs (keeping the knees bent) to one side, while keeping your torso square on the ground. Perform a standard crunch - keeping your legs turned to one side. After 30 reps, rotate your bent legs over to the other side of your body and perform the other 30 reps.
6. Plank - 1 minute
7. Leg Lifts - 30 reps
   1. Lay on your back, legs extended out together, with your heels one inch off the ground. Slowly lift your legs eight inches to a foot off the ground, keep them straight and together. Release the legs back down to one inch above the ground. 
8. Side Plank - 1 minute (30 seconds each side)
   1. This is a plank...rotated 90 degrees. So, you'll use one forearm to brace the body with your feet stacked on top of each other. The goal is to keep your body aligned, which means clenching your abdominals and using your obliques to keep your hips up off the ground.
9. Bicycle Crunches - To Failure
   1. Perform these through the burn for as many as you can mentally endure.