Serve speed refers to the velocity at which a player delivers the ball during a serve in sports like tennis or volleyball. It is a crucial factor that can influence the effectiveness of the serve, making it more challenging for opponents to return the ball. Higher serve speeds often lead to aces or weak returns, giving the server a strategic advantage. In tennis, serve speed is typically measured in miles per hour (mph) or kilometers per hour (km/h). Professional players can achieve serve speeds exceeding 120 mph (193 km/h), while recreational players usually serve at lower speeds. Understanding serve speed can help players improve their game and develop effective serving techniques.