Physical therapy attempts to address the illnesses, or injuries that limit a person's abilities to move and perform functional activities in their daily lives. PTs use an individual's history and physical examination to arrive at a diagnosis and establish a management plan and, when necessary, incorporate the results of laboratory and imaging studies like X-rays, CT-scan, or MRI findings. Electrodiagnostic testing (e. g. , electromyograms and nerve conduction velocity testing) may also be used. PT management commonly includes prescription of or assistance with specific exercises, manual therapy and manipulation, mechanical devices such as traction, education, physical agents which includes heat, cold, electricity, sound waves, radiation, assistive devices, prostheses, orthoses and other interventions. In addition, PTs work with individuals to prevent the loss of mobility before it occurs by developing fitness and wellness-oriented programs for healthier and more active lifestyles, providing services to individuals and populations to develop, maintain and restore maximum movement and functional ability throughout the lifespan. This includes providing therapeutic treatment in circumstances where movement and function are threatened by aging, injury, disease or environmental factors. Functional movement is central to what it means to be healthy.