One of the biggest reasons why people don't exercise effectively is because they simply don't know how to do it properly.

Whether due to misinformation, not enough information, or too much information, people are just confused about what exactly they are supposed to be doing!

The posts in this series will each highlight a specific exercise or exercise concept, and explain it in enough detail so that you can stick to what works, and skip the stuff that doesn't!

Bent Knee Leg Raises

There is some confusion about working your "upper" abdominal muscles vs. working your "lower" abdominal muscles. The confusion exists because there aren't 2 muscles there - it's all the same muscle - the Rectus Abdominis. 

The Rectus Abdominis is actually one long and wide muscle that runs from below your rib cage down well below your waistline. To say that you are working your "upper" or "lower" abs with any given exercise is a misnomer.

However, there are certain exercises where you will feel the fatigue of the movement in one area more than the other, which is likely how the whole "upper" ab "lower" ab confusion started to begin with. 

One of the exercises where the fatigue is really felt in the lower abdominal area is called Bent Knee Leg Raises, and it is a very effective abdominal exercise.

In order to correctly perform the movement, you start out by laying on your back with your hands flat on the floor down at your sides. Your legs are fully extended, with just a slight bend in your knees, and your head is also in contact with the floor.

The objective of the exercise is to contract your abdominal muscles - and only your abdominal muscles - and raise your legs up together until they are perpendicular to the floor, forming a roughly 90-degree angle.

You raise your legs up slowly, and control the entire motion with just your abdominal muscles, and then you lower your legs back down under that same control. Be sure to lower your legs under control, rather than just letting gravity pull them towards the floor.

Do not let your heels touch the floor! When your heels are approximately one inch from the floor, immediately raise your legs back up for the next repetition. 

There are several common mistakes that people make when doing this exercise, and they include:

• Not bending the knees. The reason for bending the knees slightly is to take the pressure off of your lower back. Failing to do so could cause a painful and long-term back injury.
• Letting the feet rest on the floor in between repetitions. The idea behind almost all resistance exercises is to keep constant tension on the muscles that are being worked. If you allow your feet to touch the floor in between repetitions, you will be allowing your abdominal muscles to rest, and you will not get nearly as much out of this exercise.
• Bending the knees too much. There are other abdominal exercises that require you to significantly bend your knees, such as the Reverse Crunch, but the Bent Knee Leg Raise only requires a very slight bend in the knees. The idea is to keep the resistance - your legs in this case - as far away from the working muscle as possible, which is the Rectus Abdominis. By bending your knees too much, you will just make the exercise easier to do, and you will not see as much benefit from the movement.
• Resting too much in between exercises. Abdominal exercises should be done back to back so that your abdominal muscles do not have a chance to recover between exercises. The abdominal muscles recover from a repetition almost instantly, so whatever exercises are part of your abdominal training routine should be done one right after another without resting in between exercises. 

For more information on how to properly do abdominal exercises, check out the Abs Like Stone site which is part of the Workout Pass Network.

Also, you can  search for information that can be downloaded, or just Ask the Experts!