What must an umpire check for before a netball match begins?

Before a netball match begins, it is essential for the umpire to check that players are not wearing any jewelry and that their nails are kept short. This guideline is crucial for ensuring the safety of all participants on the court. Jewelry can pose a risk of injury not only to the player wearing it but also to other players during the game. Additionally, long nails can lead to unintentional scratches or injuries during play, which can also compromise the safety of the athletes involved. Ensuring that players adhere to these requirements helps maintain a fair and safe playing environment, which is a fundamental responsibility of the umpire.

While the other options might touch upon important elements of game preparation, they do not address immediate safety concerns in the same way. Matching uniforms ensure team cohesion, medical clearance speaks to player health, and electronic shoe checks involve equipment regulation, but none of these directly relate to the immediate physical safety risks presented by jewelry and long nails.