Cerebral palsy is an injury to the brain, but what we find is that it has a lot of effects on how you use your muscles.
For people with a physical disability, activity is a lifestyle. It's something that can start in physical therapy, but it really is something that has to be carried over into their everyday lives. What has happened over the years is we're understanding the importance of mobility.
To give you an idea about genetic variation between each of us, there are about three million differences in our genetic code. They go to influence the color of our hair and the color of our eyes, the way we walk.