fitness. VO2 max, or maximal oxygen uptake, indicates the amount of oxygen consumed in millilitres per kilogram of body weight per minute. The higher the number, the more oxygen you get to the muscles, and the faster or longer you run. Tergat's oxygen
. The non-weight-bearing nature of most cross-training lets you go hard several days in a row.3 Go longerMost cross-training requires 1.5 to two times the duration to accomplish the same training effect as running. So if you normally run 30 minutes a day
