> In fact, when I model the average response to training across the entire group that I have VO2 and long-term training data for, I see an average shift from 54

> In fact, when I model the average response to training across the entire group that I have VO2 and long-term training data for, I see an average shift from 54 to 67 ml/kg/min (a change of 24%) when a long-term, high-volume training plan is undertaken. > > Conversely, when a short-term, high-intensity training plan is undertaken, the model shows a maximal increase (in 4-6 weeks) to only 63 ml/kg/min (16%). > > So, while a 40% increase in VO2 max may not be considered “typical,” after my experience testing and observing athletes over the past 10+ years, I would have to consider a ~25% increase in VO2 max to be very typical given the right training over a sufficient period of time (the two items missing from those initial studies that suggested high genetic limitations). Bait and switch. He starts out talking about averages over ordinary people suggesting 10-15% average improveability, and then presents a 25% estimate... from an extremely selected group of athletes after lots of attrition from those getting worse results (just what percent of the population even has VO2max numbers from a "long-term high-volume training plan"?). I would suggest that his end result strongly reinforces the original claim, rather than debunking it.