Body posture is very important in prevention of backache. Choose a good chair for sitting; especially at the workplace. Do not use a chair that has no backrest or handrest. Do not sit in a stool for long time.
Use a chair with cushion rather than wooden or steel surface. Do not sit on the edge of the chair. Lean back fully and rest your back on the chair. You could also use a soft pillow to support the back or lower back.
Sir erect. Do not stoop, bend or slouch while sitting. Position your computer in such a way that you can sit straight. Do not sit in a crooked, twisted or awkward position. Do not be seated for hours at a stretch. Move around after an hour or so. Do a few stretching movements for your hands and leg muscles, and rotate your neck slightly so that it does not get stiff.
Exercise regularly. You can choose activities meant specifically to exercise the back region. For example, rotate your hip in clockwise and anti clock wise direction each 10 times. Stand straight, raise your hands to the ceiling, and try to touch your hands to the ground by bending your back. You can do this activity 10 or 20 times.
Similarly, you can sit on the ground, lock your hands slightly at the back and touch your head to the ground and come back to the straight sitting position. You can also keep your hands on the hips and turn 45 degrees to the right, come back to the original position and then turn 45 degrees to the left.
Avoid lifting very heavy objects or strenuous weight lifting exercises, unless you are being supervised by a trainer. Do not apply pressure on your back; rather use the muscles of the hands, thighs or stomach while exercising.
Eat energy giving food like proteins, cereals, whole grains, vegetables, green leafy vegetables, milk and milk products etc. Also, keep track of the calcium intake in the body for strong bones.