Volleyball is a game that requires speed and focus, i.e., no distraction. When the Volleyball sport was created, it was discovered that longer shorts moved too much. Most players had issues jumping, landing, or moving around on the court because of them. It was uncomfortable; therefore, spandex shorts were introduced. With these shorts, there is enough room to land, jump, and do several things undisturbed. This is why shorts are recommended for the sport, and not otherwise.