To train the muscles of the back, you need to regularly exercise to strengthen lower back. One of them looks like this: starting position - on all fours, his knees and elbows into the floor. Actually exercise is a simultaneous lifting of the right hand and left foot. They definitely need to straighten parallel to the floor. Hold body in this position is at least 2 seconds repeat the exercise 10 to 20 times. And don't forget to alternate arms and legs.
Use another no less effective exercise. Lie on the floor on your stomach, hands along the torso, slightly lift the legs and head so that a small deflection in the center of the waist. Try to keep the position of the body for a few seconds. Then slowly return to starting position. When you can repeat the exercise 20 times, put himself under the breast cushion to increase the load.
Do some stretching. Nothing helps strengthen the lumbar muscles as stretching. Sit on the floor or training Mat, bend your knees. Now you need to hug them so that you could omit to the chest chin. Then arch your back so that it widened, and then slightly lean backward. Take your time and slowly return to the starting position.
Another exercise is: lying on your stomach and begin to tear the legs off the floor one by one, and then put them back on the floor. After warming up, take the leg back (be careful that it was straight and the pelvis was not off the floor) and hold it so 3 to 5 seconds. Change the leg. Now lift first one leg, then the second, then to lower both slowly and smoothly.
A great way to strengthen the muscles of the lower back - legs. Lying on stomach, raise both legs, then slowly and carefully spread them apart, then join together and push. Can also try Wraith the lumbar spine as follows: lying on stomach, raise both legs and hold in this position for some time (as I can), then carefully lower.
Be very careful when performing any strength exercises, you need to choose the manner of execution of training where you feel no pain. Any, even the slightest discomfort is a signal to stop the workout. After all, you risk breaking the back and the treatment will take a lot of effort, time and money.