Final answer:
Exertion is not considered one of the elements of progression in exercise; elements like duration and strength are part of a systematic approach to increasing workout intensity over time. (option 2)
Step-by-step explanation:
The student is asking about the elements of progression in the context of exercise and fitness. To answer which of the following is not an element of progression: Duration, exertion, or strength—exertion is not typically categorized as an element of progression. Progression in exercise refers to the systematic increase of the intensity or workload over time to continually challenge the body and facilitate improvements.
Duration refers to the amount of time spent exercising, while strength refers to the amount of force a muscle can produce. Exertion is more of a subjective feeling of how hard one is working during physical activity and is not a specific element of progression. For a systematic approach to improving fitness, elements such as duration, intensity, frequency, and overload are carefully adjusted.
Hence, the answer is option 2