Sensei Sandeep Desai on the 70 % threshold in Taoism...
At the heart of Tao philosophy is the 70% rule. It states that you should do a T’ai Chi movement to only 70% of your potential.
Staying within 70% of your capacity produces optimum physical accomplishment, simultaneously reducing psychological stress.
I found this interesting because medical science have also stated of a link between moderate exercise and longevity.
I know of a couple of athletes who died of a heart attack while going through rigorous physical regimens.
Similarly working at 70 percent capacity can also bring conditions of creativity, enjoyment of work and performing work mindfully.