Never punish or scold a child for lack of ability. All you can expect them to do is their best (e.g., Don't make those who lose a game or come in last run laps, or do jumps, or sit out while others play). Tell everyone, including the unathletic players, that you are proud of them if they are trying hard. You will have some athletic players and some unathletic players. Measure each player's performance by their personal improvement & effort, and not by comparing them to someone else. Try to motivate in a positive way that builds self-esteem. See "Incentives" below for ideas about rewarding practice and game attendance, hustle and effort.