NAFC Trainer Practice Exam 2025 – The All-in-One Guide to Master Your Certification!

For endurance training, the focus is on performing a higher number of repetitions with lighter weight to improve muscular endurance and cardiovascular performance. The range of 10 to 20 repetitions is optimal because it allows the muscles to work over a sustained period, which is essential for building endurance.

This repetition range promotes adaptations that enhance the muscles' ability to resist fatigue and increases the efficiency of the cardiovascular system. It also helps in improving metabolic pathways that are vital for prolonged activities. Options that suggest fewer repetitions, such as 1 to 5 or 6 to 9, are more aligned with strength and power training, where the emphasis is on maximal force output rather than endurance. The option of 20 to 30 reps might be too high for most resistance training contexts, though it may be beneficial for certain types of endurance exercises. Therefore, 10 to 20 repetitions strikes a balance that effectively develops endurance while still allowing for adequate load and muscle engagement.