Changing the Lead & Saving Ground

Question
Two commonly used terms neither of which are clear to me are "Changing the lead" and "Saving ground."  Can you help?  Thanks!

Answer
hi bill -- well changing the lead means  when the horse is on his or her's right or left lead. when they break from the gate, the horse should be on it's right lead, when they make the turn for home.  they are on the left lead. saving ground  means that the horse will keep to the inside of the track during the race, thus  saving ground on the turns. hope this helps you thanks ED