That means we don't have too many myoglobin carrier proteins. And so these muscles will appear white. So these are known as the white muscles, but these two muscles are known as the red muscles because these have a fast contractile rate. That means these two are known as fast twitch muscles. But this, which has a low contraction speed, this is known as a slow twitch muscle. So once again, these are the muscles that are found predominantly in the back and the legs.