Back and stomach muscles are antagonist muscles. This means that if one is contracting the other is stretching. A three-leveled approach with gradual progression from one level to the next makes it possible to build strong and well shaped stomach/back muscles, safely.

For each level of experience, swing your right leg slowly 8 times backwards, and then repeat it to the left side. Finish by walking around and shaking your legs and arms for a minute. Repeat the full process once or twice. The following two examples show the importance of proper technique.

		Each exercise should start with proper warm-up. In this'‘plie” position, fingers are grabbing (and protecting) the knee joints while lightly bouncing in harmony with the music.
		For back / stomach muscles, start in this position, with straight or a bit rounded back.
		The following example shows the three different levels of an exercise.For beginners, leg lifts should stay close to the floor (especially if you have a history of lower back problems).
		After one or two weeks of exercising at the beginner level, you can move up to the intermediate level. At this stage, lift your legs to the horizontal position. This is a very safe lower back strengthening move.
		At the advanced level, leg lifts are upwards. It takes some time and flexibility to get to this spectacular move. Even well-trained and fit users will be challenged.