Physical therapy is a healthcare profession that enables therapists to evaluate and treat people with musculoskeletal disorders, neurological dysfunctions, and other types of disease, injury, or illness. Although physical therapy is relatively new, it initially began during World War I (one) and has grown dramatically in recent years. Physical therapists can now specialize in pediatrics, sports medicine, home health, orthopedics, aquatic therapy, and many other areas. Manual therapy and joint mobilization are only two of the special skills used by therapists to help lessen disability and pain. When treating patients, some therapists may use special equipment called 'modalities' (moh-DAHL-ih-ties) that help aid in the healing and recovery of an injury, such as electrical stimulation, hot and cold packs, infrared (in-FRUH-red), and ultrasound. During the treatment process, a therapist may stretch and strengthen muscles, challenge balance, test coordination abilities, teach home exercise programs, and enhance basic mobility skills, such as getting out of bed.