Reply: A strain is an injury to a muscle resulting in partial or total tearing of the muscle. There are three levels: mild or first degree, moderate or second degree, and severe or third degree. They are caused by sudden movement, overuse, forceful stretching, violent contraction or unaccustomed repeated minor trauma. Sprains are an injury of the joint, in which the bones momentarily come out of alignment such that joint structures i.e. ligaments, joint capsules and possibly tendons, will be torn. There are also three degrees of sprains. Sprains can be caused by a violent, sudden bend or twist beyond the normal range of motion of the joint