Too much focus on numbers can be counterproductive. “Very few people take into account the psychological ramifications of all this science-y data,” says Steve Magness, the running coach and coauthor of Peak Performance. “The more you measure, the more you create athletes who are fragile. I’ve seen it at the largest stage with world-class athletes. They become dependent. If the fancy HRV or omega wave tells them they aren’t ready, then they believe they are not ready.”
