Final answer:
Swimmers and athletes must assume the correct preload position before the start of each match to optimize their body position for a quick and powerful start.
Step-by-step explanation:
Before the start of each match, swimmers and athletes must place themselves in the correct posture, known as the preload position.
In swimming, this involves crouching down on the starting blocks with one foot forward and hands gripping the edge of the block.
In athletics, such as sprinting, the preload position is a crouched stance with hands on the ground and one foot forward.
The purpose of the preload position is to optimize the athlete's body position for a quick and powerful start, as it allows for maximum balance, stability, and explosiveness.