Joel Harper from Runners World TV is going to show you how an ab workout properly named the "karate kid". For this ab exercise you are going to need a small medicine ball preferably one with sand inside and you are going to want to place it between your two feet while standing. Now, you want to squeeze the ball with your feet and then jump and try and toss the ball as far as you can into the air. Depending on the health of your knees you can work on flexibility also by after throwing it into the air try and land on one foot or both if you have knee problems. Now for an extra challenge you can place your hands behind your head and then attempt to complete the jumps but you want to do 10 jumps switching which leg you land on.