I love this abdominal workout. My clients always give me an audible response after a set of these! If you have a hard time bringing the lower abdominals into contraction, this is the move for you.
With the 90-degree ab crunch, you are using two different weights to pull, as opposed to one weight to pull with a standard abdominal crunch. With the standard crunch, your upper body supplies the weight that your abdominals has to pull up. With the 90-degree ab crunch, you will also have the legs in position to act as a weight resistance or leverage disadvantage. This movement is so complete that it will even bring the obliques into the movement.
When performing this movement, it is important to keep the abdominals tight the entire time you are completing repetition. If you release the contraction, you may experience back fatigue. This is true with all ab movements, but especially this one.
Consult a Physician before starting this or any exercise program.
90-Degree Abdominal Crunch/Leg position
You can see the position my legs are in. One leg is at a 90-degree angle and the other foot goes to the inner knee. This may seem a little awkward at first. Remember, keeping your abs tight will enable you to maintain this position. Think of your legs as one unit glued together. The leg unit is the second weight your abs will be pulling against.
90-Degree Abdominal Crunch/Exercise
Do two to four sets of 8 to 25 repetitions at each leg position. Switch leg positions for balance and repeat repetition.
Here it is. Exhale as you pull both the lower and upper body components together. Relax the neck into the palm of the hands. Remember, it is your abs that pulls the upper and lower body together and not your arms and legs contracting to achieve this motion. Be careful not to release the upper and lower body units too far to the ground, as it may encourage too much extension in the lower back. Once you've completed the repetition, switch legs bringing the other foot to the inner thigh of the 90-degree leg.
If you have not trained your abs before, you should start with some basic abs. (See anatomical ab techniques in previous articles.) Once you have some ab strength and muscle awareness, you'll be ready for the 90-degree challenge.