Need ‼️ marathon runners?
a: can run only one or too marathons a year
b: tend to have more slow-twitch muscle fibers
c: only eat carbohydrates
d: are always very thin

People who utilizes the progression principle will ensure their exercise program increases in frequency, intensity, time, and type. the changes need to happen gradually in order to ensure they make gains in their fitness program. a person who doesn't utilize the progression principle can still gain health benefits from exercising, but will not continue to improve in cardiovascular fitness.