When it comes to choosing the best rep range for muscle growth and definition, many people still hold outdated misconceptions. High reps, typically involving sets with more than twelve reps, are often believed to lead to more defined muscles, but this is not true. Muscle definition is primarily influenced by muscle size and body fat percentage. Both high and low rep training can be effective for muscle growth, with high reps promoting metabolic stress and low reps recruiting fast twitch muscle fibers. It is recommended to combine both high and low reps for optimal results.