Which advantage do parents who wait to have children enjoy? more energy
derer goals
stronger mariages
higher intelligence

It settles nerves, reduces the tension.

The person who utilize the progression principle will keep adding the difficulty of the exercise that he's doing, while the person who does not, will only stay stagnant.  the person that utilize progression principle, will get a stronger endurance because now his body is conditioned to do harsher routines.{the answer was already on verified)