And we were both disappointed.
When I reviewed the two graphs from the study by Reynolds and Taylor, that comment from the movie Spirit of the Wind came to mind. George Attla and his trapping partner Moses traded dogs sight unseen. One dog turned out to be blind and the other had only three legs.
What is the take away from the study? VO2 max does not mean much and has very little predictive value for practical running endurance or performance when applied to individuals or groups. VO2 max is a well-defined quantity that can be measured relatively accurately and easily. Unfortunately as the results of this show, it does not correlate to endurance or running performance over distance. No one should expect that the Labrador retrievers on the high fat diet can run a 20 km race competitive with the better trained sled dogs, even though the VO2 max values are similar in both groups.
What were the diet variables? Was the protein content the same for all diets? What would the Labradors’ V02 values be if they also trained the same as the sled dogs? That would make the study more interesting. My understanding was that the study resulted from Richard Taylor’s challenge to Reynolds based on Taylor’s understanding of comparative physiology for many different species and his observations that between species the aerobic capacity was linked to endurance performance and fat metabolism and adaptation… echoing David Kronfeld’s earlier work with dogs.
Jack Daniels’ Vdot recognizes the limitations of VO2 max. Vdot is derived from measured running times over shorter distances that the athlete has trained for, and predicts the best performance that could be expected if the same athlete trained for longer distances properly-as illustrated and defined in Jack Daniel’s book, Running Formula.
Performance is determined by three variables or factors, and training can improve all three, but most practical training methods use a series or cycle of workouts and schedules that target the three separately. The three are: speed (which is somewhat reflected by VO2 max,) endurance, and recovery/recuperation. When you focus on speed you typically reduce the endurance; when your training focuses on endurance you typically reduce the speed; so the balance of training determines the overall results.