Substitution requests are allowed under which of the following conditions?

Substitution requests are allowed prior to the start of the set because this is a time when teams can make necessary adjustments to their lineup in preparation for the match. It allows the coach to strategically decide which players will participate and ensure that they are putting forth their best lineup right from the beginning.

In volleyball, this provision is crucial for setting up the game according to each team's strengths and tactical approaches. Substitutions at this point are not restricted by game dynamics or the need for specific situations, making it a standard practice to finalize the roster before play begins.

Understanding the timing of substitutions is important for officiating, as it impacts player rotations and compliance with the substitution rules throughout the match.