Only those who have actually experienced periodic back spasms or chronic back pain understand how debilitating it can be; it makes even the simplest acts like getting in and out of a chair, or bending to tie a shoe intolerably painful. Most of the time, rest seems to be the only answer for a painful back, but there may be instances when some limited movement is advisable.
As soon as you begin experiencing sever back pain call your doctor. Find out how long you should remain immobile with bed rest; there are times when being on bed rest for more than two days can be counter-productive, and may actually slow your recovery
While you back may not be capable of much movement, the rest of you limbs are functional and need to stay active. Having weak legs when your back feels good enough for some exercise is not going to be helpful, and will simply extend the time it takes you to get back to normal. For more info see http://www.backpainreliefhelp.com/Back_Pain_Exercise/ on Back Pain Exercise.
Keep Your Legs Moving
At the very least, make an attempt to stand up each day. There is a danger that, if your legs are idle for long periods of time, the may develop blood clots. Getting back on your feet even briefly will help maintain normal blood circulation in your legs.
One Lower Back Exercise
If you are able to get from your bed onto the floor, then lie stomach-down on the floor and support yourself with you elbows. Push up with your elbows so that your stomach and chest are raised while your hips remain in contact with the floor. Get your stomach and chest raised as far as you can without forcing them, and when you can not longer hold the position, roll over on your back and place a rolled towel or pillow beneath your lower back.
This exercise is designed for people whose problems originate in their lower backs; it is most effective for those whose pain radiates from the center of the back outwards.. If your back pain seems to radiate not from the center but from one side, lie on you stomach as explained above, and place your weight on the hip opposite the painful area of your back. Then continue with pushing you chest and stomach off the floor.
There are things that go without saying when you are incapacitated with back pain: no sudden movements, no lifting, no sitting without good back support--and no driving if you can possibly avoid it. Move as much as you can, and when you can stand up, stand as straight as possible.