Scenario: With 1 out and a runner on third-base, the batter hits a sacrificial fly ball to right field, enabling the runner to head for home.
Traditionally, the runner sits on third until the fly is caught, then begins his run home, starting from a dead-stop.
It appears the runner would be faster if he took a few steps down the third base line, away from Home, and begins his run at a full sprint, moments before the fly-ball is caught. He'd tag up on third just after the catch, and already be moving at full speed towards home. That is far faster than starting at third from a dead stop.
I cannot find anything in the MLB Rules prohibiting this, but I don't see it done.
Is this idea legal? Is it faster? Or am I missing something?