NGC investigates the science of muscle by taking us on a journey inside the bodies of two remarkable humans with startling genetic conditions. 31-year old Jason Dunn lives with Dystonia, a rare disorder that causes his brain to

send faulty messages to his muscular system. Every waking moment his muscles flex out of his control, twisting his body into unusual positions. Ami Ankileweitz has Spinal Muscle Atrophy, a condition that has caused his muscles to wither away.
Read more: http://channel.nationalgeographic.com/series/extraordinary-humans/4923/Overview#ixzz1IBm1P14e