David Drake

We have 2⃣ exciting new opportunities to join the team at our High Performance Centre 🆕 🧑‍🍳 Executive Chef 🏋️ Academy Athletic Performance Coach Find out more 👇

On "VO2max intervals" to improve VO2max... Medium duration intervals at a high intensity are often cited as a way to improve VO2max e.g. 5 x 5 min @ 90-100% MaxHR w/5 min recovery. And, indeed, when carried out over short periods of time (4-12 weeks) significant improvements in VO2max are often seen. However, most of these improvements that come from this "sharpening" training are in the *anaerobic*, not the *aerobic* system. Let me explain... Everyone has a limit in the O2 debt that they can accumulate from the anaerobic "bank" during a maximal effort. This can range anywhere from 10-20L, or 1-2L/min over a maximal 10 minute test. A greater credit score with the anaerobic bank will allow the athlete to go a little deeper into the red before going bust. However, the aerobic system has a much higher capacity to generate energy. For a fit athlete, over a 10 minute maximal test, they could power 50L or more from the aerobic system (5L/min)! Because, when a test starts, it is the anaerobic system that kicks in first, the longer that the athlete can "hang in there", the more of the aerobic system they can eek out. For very well trained athletes, with a very strong aerobic system, this ability to eek out the full extent of the aerobic system can be quite limited by their anaerobic capacity (as shown in the chart) for an athlete with a VO2max of 4.5L/min (well trained) It is common for very well trained athletes to have low lactate levels - much lower than sedentary, untrained, people - their aerobic system becomes so strong that it overpowers their anaerobic system. They simply don't have the anaerobic capacity to eek out the full extent of their aerobic capacity. For most of us, however, this isn't an issue - our anaerobic system is stronger, by default, than our aerobic system. When not well trained, say, a VO2max of less than 4L/min, the anaerobic system is rarely limiting (as shown in the chart, it only takes an anaerobic capacity of 1L/min over a 10 minute test - 10L to get there!) &, so VO2max intervals aren't as useful/indicated. In summary.... Our default state is anaerobic strong/aerobic weak It takes quite a lot of aerobic training before this balance starts to shift in the other direction When athletes see an improvement in VO2max after high intensity training, it is *anaerobic* improvement that allows them to fully exploit the work they have already put into their aerobic system, i.e. their aerobic *base* You can only sharpen the base you've built.