Final answer:
In pickleball, an underhand serve with one foot behind the back line is called a diagonal cross-court serve. The ball must clear the non-volley area, and hitting it diagonally increases the chances of success.
Step-by-step explanation:
In the game of pickleball, an underhand serve is performed with one foot behind the back line. This type of serve is known as a diagonal cross-court serve, where the ball is hit at an angle across the court.
When making the serve, the ball must clear the non-volley area, which is a designated area near the net where players are not allowed to hit the ball on the fly. By hitting the ball diagonally, it increases the chances of clearing the non-volley area and landing the serve in the desired location.
By executing an underhand serve with one foot behind the back line and hitting it diagonally cross-court, players can strategically place their serve and gain an advantage in the game.