Stiff person syndrome is a rare autoimmune neurological disorder that is more common in women. Celine Dion has been diagnosed with the condition.

That deep ache you feel a day or two after training isn’t random—it’s a powerful biological signal that your body is rebuilding stronger than before.

Stiffness often accompanies back pain. On hands and knees, slowly arch your back upward, then gently lower it into a comfortable hollow. Move in a controlled manner without forcing the range. Perform ...