Running is a simple sport, but it's not so simple that runners don't make lots of mistakes in their training. Ironically, many of these mistakes occur when runners are talked into making the training process too complicated.
Problems emerge when coaches and scientists substitute the true goal of training—better performance—with specific physiological objectives such as maximizing the muscles' ability to burn fat. These physiological proxies for performance are too often treated as the be-all and end-all of running fitness. They can be used to create training programs (and sometimes diet plans) designed to maximize this one dimension of the physiological recipe for running fitness without a care for how other dimensions are affected.
Invariably, these unbalanced practices stymie the progress of runners who are unfortunate enough to fall for the underlying doctrine.
The reality is that running fitness has numerous components, none of which is the be-all and end-all. It's best therefore to forget about physiology and focus on performance. The most effective way to maximize running performance is to follow a balanced training program that covers all of the physiological bases.
Let's take a look at three of the most commonly promoted performance proxies and see why placing too much emphasis on any of them leads to unbalanced, ineffective training.
The concept of VO2 max, an acronym for "maximum rate of oxygen consumption," was discovered by English exercise physiologist A. V. Hill almost a century ago. Hill observed that regular exercise training increased the maximum rate at which individuals were able to consume oxygen during workouts. He also noted that those individuals who were able to consume oxygen at the highest rates tended to perform best in fitness tests.
These observations led Hill and other exercise scientists of the time to conclude that VO2 max, also known as aerobic capacity, was the be-all and end-all of endurance performance.
Subsequent research revealed that high-intensity interval training was the most efficient way to boost VO2 max—efficient meaning that small amounts of training at high intensity increase aerobic capacity more than small amounts of slower training. This finding led to the development of training programs dominated by speed work.