Asap to work on muscular strength, you should use - heavier weights and decrease repetitions - heavier weights and increase repetitions - lighter weights and decrease repetitions - lighter weights and increase repetitions

The answer would be age 18.

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.