Although there is no evidence that exercise can lessen the curve of a scoliotic spine, there is also no evidence that proves any contraindication between exercise and scoliosis. Most studies have found that scoliosis patients can participate in sports just as vigorously as unaffected peers, except for a brief period of recovery after surgery. Non-surgical patients are advised to exercise regularly and to exercise in their brace if they are using one. Your doctor can give you a more specific recommendation based on your specific condition, but there are a few things that people with scoliosis should avoid, or at least be wary of.
No matter what exercise you do, it is important to learn proper form. This allows you to keep an upright posture that supports your body properly instead of leaning to one side simply because that is the way your body naturally positions itself. Poor form can lead to unbalanced muscles, nerve damage, and can even increase your back pain. When you work out without a trainer, work in front of a mirror and strive to maintain level shoulders and hips. Keep your head in line with your neck, and always look straight ahead.
High impact exercise isn't good for anyone's joints, let alone someone with a spinal curve. The whole point of exercise is to make you feel better, not to damage your spine and increase your pain. Opt for low- or no-impact exercises like swimming or cycling instead of running or plyometrics. If you won't be happy unless you can run, go out of your way to practice good running form, run on shock absorbing surfaces like grass and sand, and wear well-cushioned running shoes.
If you think running might be hard on your spine, imagine getting pummeled by an entire defensive line. Collision sports like football, boxing and wrestling have the potential to cause damage to your spine whether you are on the giving or receiving end of the blow. Scoliosis means your spine is already curved -- severe impact from any angle can cause tremendous pressure on your vertebrae. It won't make the curve worse, but it can cause tiny fractures that can weaken the spine over time.
Torque sports involve spinal twisting. It's a tricky situation, because a gentle spinal rotation that stops within your pain threshold, like a yoga seated spinal stretch, can actually be a good way to relieve back pain. But sports like gymnastics and martial arts that require fast, high-powered spinal rotation can easily force you beyond your comfort zone and end up causing you more pain in the long run. It won't make your scoliosis worse, but there's very seldom an opportunity to stop when it hurts or favor a particular side -- the rotation is usually part of the mechanics of the stunt, and failing to rotate properly can cause an unsafe landing that definitely could damage your spine.