A custodian was working from a portable scaffold system approximately 15 feet above the floor of the gym to repair lights in the scoreboard. Two additional employees were holding onto the scaffold at floor level. The employees tried to move the scaffold while the custodian was still on the platform. The scaffold tipped over and fell to the floor. The custodian and one of the employees on the floor suffered injuries. The custodian was hospitalized with a fractured knee cap and heel. The employee on the ground was treated at a hospital and released.