The doctor explains to Stephen Hawking that Motor Neuron Disease is affecting his ability to use any muscle activity, such as speaking, walking, breathing, and swallowing. The signals that tell the muscles to move are disrupted, and the result is gradual muscle decay.
Jeffrey provides an overview of muscles and explains how they help our bodies move. He then describes how muscles grow in size and mentions that muscles need more than activity to grow: they also need proper nutrition and rest.
Neuroscience can help an athlete perform better at the Olympics, instead of relying solely on phsycial conditioning. It can active muscle memory, so the athletes' body can go into auto pilot and perform its best.