The physiotherapy professional has an array of tools at her disposal to work with these conditions. Exercise, aqua therapy, electrical stimulation, and more can be used. The third category is skeletal problems. Geriatric physiotherapy helps people who have these disorders, such as osteoporosis and osteoarthritis. One example of the many sports injuries is an anterior cruciate ligament (ACL) injury. This is an injury to the knee. It is one of the common sports injuries in people who play sports that challenge their knees, such as hockey, skating, skiing, basketball, and of course, football. It can limit the range of a player's motion in that leg, and make the leg weak. With these two skills in place, the patient will have a more advanced ability to do aerobic and other exercises. Aquatic exercise is also used. Patients with neurological conditions must live with many problems of lack of movement and function. Physiotherapy can help them to overcome some of these problems. Different physiotherapy credentialing agencies are relied upon in different states. Some require a score of 600 or more on the licensing exam. Some require on-the-job training or professional references from physiotherapists who observe them in training. Most states also require some ongoing education to keep physiotherapy credentials current. As always with physiotherapy, the first step is evaluation. A plan is formulated that will include therapies specific to the kind of spinal cord injury the patient has. Neck injuries can cause quadriplegia, which requires special treatments. An important issue in spinal cord injury is the level of the damage. This is because, as they have trouble breathing, they avoid walking or doing physical exercise of any sort. The goal of physiotherapy in this case is to strengthen the legs through treadmill-walking or stationary-cycling. This can only be done, however, if the patient is well enough to start out. Conditioning the arms of chronic airways disease patients is just as important.