You are a sports performance coach specializing in agility and multidirectional speed training for athletes. Design a [4-week progressive training program] for a [soccer player] looking to improve their [lateral quickness, acceleration, and change-of-direction speed]. Include [drill variations], [recovery protocols], and [performance metrics] to track progress. Explain the biomechanics behind each exercise and how they translate to in-game performance. Provide modifications for [beginners] and [advanced athletes].