Final answer:
The energy cost of exercise is most commonly quantified using METs, which are multiples of a person's resting energy expenditure, whereas calories represent the energy from food. Watts measure power output and are not typically used for energy cost of exercise, while repetitions are simply a count of how many times an exercise is performed.
Step-by-step explanation:
Energy Cost Units in Exercise:
The energy cost of exercise can be presented using metabolic equivalent tasks (METs). METs provide a convenient way to quantify the energy expenditure of various activities as multiples of a person’s resting metabolic rate. Essentially, 1 MET is the energy consumed while at rest, and activities are scaled based on how many times more energy they require compared to resting. For example, if an activity is 5 METs, it requires five times the energy expenditure compared to resting.
Similarly, the calorie is a familiar unit of energy particularly referenced in nutrition and exercise. It is defined as the amount of heat needed to raise the temperature of one gram of water by one degree Celsius. The kilocalorie or Calorie (with a capital ‘C’), equivalent to 1000 small calories, is often used to quantify the energy values in foods.
Watts are units of power rather than energy and represent the rate of energy usage per unit time. They are not normally used to describe the energy cost of exercise. Instead, Watts are more fitting for measuring continuous power output, as seen in cycling or rowing performance. Repetitions, on the other hand, denote the number of times an exercise is performed and are unrelated to direct energy cost measurements.