There are no hard-and-fast rules on how rapidly one should progress to a higher level of activity. The individuat's subjective i
mpression of whether or not the body seems to be able to tolerate increased training serves as a good guide. In general it might be reasonable not to progress to higher levels of activity more often than every one or two weeks. How is the word subjective used in this excerpt?
The word subjective is used here as an abstract. It refers
to the theoretical ability of a person idiosyncratic to his body's capability
to increase level of activity in a constant frame of time. It supports the idea
that there is no one template for everyone to follow.
