High intensity training is an essential part of the endurance athlete’s tool kit. If only just going out and hammering would enable us to achieve our goals, but it’s not that simple. Yann LeMeur shared a comprehensive infographic on the variables to consider when programming interval training. One caveat: the amount of VO2 max work for endurance athletes may need to be adjusted. Depending on the athlete’s age and goals 10 minutes of hard work is too little.