The fundamental tenets of training haven’t changed much in decades.
When planning your workouts, keep these general principles in mind:
If intensity is high, volume is low.
Volume never increases more than 10 percent per week or more than three weeks in a row.
Weekly intensity is measured by the number of hard workouts, from none to three.
Follow hard days with easy days, not rest.
At least one day per week, and one week per five-week cycle, is devoted to recovery.
—“To Each His Zone,” May 1993 Outside Magazine