Which of the following is NOT a key principle for optimizing practice conditions according to the course content?

The correct answer reflects the idea that "irrelevant feedback" does not improve practice conditions. In fact, positive and relevant feedback is crucial for effective learning and skill enhancement. It helps golfers understand their strengths and weaknesses, allowing them to make necessary adjustments during their practice sessions.

On the other hand, practice timing, motivated practice sessions, and the right amount of practice are all essential principles that foster better skill development. Proper practice timing ensures that golfers are focused and engaged, while motivated practice sessions encourage sustained effort and improvement. The right amount of practice is also important, as too little or too much can hinder performance. Thus, focusing on relevant and constructive feedback is vital for optimizing practice conditions, making "irrelevant feedback" the correct choice for this question.