Which of the following tasks does not fall under the duties of a chief judge?

The correct choice indicates that coaching gymnasts during a routine is not a duty of the chief judge. The primary role of a chief judge is to oversee the judging panel and ensure that judging standards are upheld during the competition. This includes preparing judges for competition, ensuring that all apparatus used is compliant and safe, and averaging the scores given by judges to arrive at a final score for each performance.

Coaching, however, is a role typically taken on by designated coaches who work closely with the gymnasts to enhance their skills, develop routines, and provide guidance during performances. The separation of roles is essential in gymnastics competitions to maintain impartiality and fairness; judges must not have any influence on the gymnasts during their routines. Thus, the task of coaching falls outside the chief judge's responsibilities, making it the correct answer for this question.