In CrossFit terminology, intensity is defined as what?

• A. The independent variable most commonly associated with maximizing the rate of return of favorable adaptation to exercise
• B. The total duration of a workout
• C. The number of exercises performed in a session
• D. The time under tension of a single muscle

Answer: (D)

Intensity is how hard the body is working during an exercise. That effort is most clearly captured by the time a muscle stays under load in a rep—its time under tension. When you lift heavier, move faster, or shorten rest, you increase this muscular demand and raise the workout’s intensity. Total workout duration or simply counting how many different exercises you do describe volume or duration, not the immediate intensity of the effort. So, time under tension of a single muscle best reflects how intense the effort is on a given movement.