Целесообразно ли выполнять упражнения при наличии Синдром мышечной скованности? Какие упражнения Вы бы порекомендовали и насколько они должны быть интенсивными?

I believe it is always best to keep moving. If all you can do is wiggle your toes then wiggle your toes and try to bend your foot.
Exercise will depend on the individual. Short walks daily if possible. Even if wheel chair or bed bound it is important to try to move and stretch all parts of your body (slowly and gently) to prevent some stiffness. Being honest I think that exercise is most beneficial to those with low mobility. With the help of a gentle physical therapist who understands SPS brought me from bed bound to walking through my house without assistance.