Part 7 – Review
Through the first 6 parts of this series we have discussed in some detail the current state of the art of running and endurance physiology. In this final part we will review the major points covered and advance an alternate theory for the reader’s consideration.
The theory currently dominating the exercise physiology world, at least from the perspective of training recommended by leading authors, trainers, the popular press, and coaches, is that of VO2max. The concept of VO2max holds that the limiting factor in endurance performance is the body’s ability to absorb, transport and utilize oxygen. Put succinctly, the reason you can’t run faster is that you can’t get enough oxygen to your running muscles. When you increase the amount of oxygen available to your muscles, you will then be able to run faster.
Due to some significant challenges to the theory of VO2max, two additional factors have been proposed by exercise physiologists for explaining endurance performance limitations. These two factors are lactate threshold and running economy.
A runner produces lactate in greater and greater quantities as running speed increases. This is believed to happen because of the body’s inability to provide sufficient oxygen to meet the increasing energy needs of the muscles. It is widely believed that lactate is a prime cause of fatigue and hence limits performance. It is further believed that lactate does not increase linearly, instead it increases in a threshold manner, such that at some running speed the amount of lactate being produced by the body increases significantly. The theory holds that if a runner can increase the pace at which he can run before crossing this “lactate threshold” running performance will be significantly improved.
Running economy is a measure of the amount of oxygen a runners uses at any running speed. It has been observed that even though a group of runners may have the same VO2max, the amount of oxygen they use at any running speed can be very different. This difference or “running economy” is used to explain why it is possible for a runner with a lower VO2max to beat a runner with a higher VO2max.
Since VO2max, lactate threshold, and running economy are the dominate beliefs, most (all?) running and endurance training programs are designed around these beliefs and are crafted to improve one or more of the above variables. Workouts such as tempo runs, aerobic runs, anaerobic runs, lactate threshold runs, and VO2max runs have been promoted as methods to improve one or more of the above factors. Additionally, basing workouts on some percentage of heart rate and using a heart rate monitor to stay in the appropriate range has been an easy method to employ the workouts mentioned above without the necessity of expensive laboratory equipment or trained technicians.
Do They Really Exist?
Significant challenges to the concepts of VO2max, lactate threshold and running economy exist. The counter arguments are based on research, empirical evidence, and logic. The most significant of these challenges concerns the assumption that VO2max limits performance; it has always been assumed that VO2max limits performance but has never been proven. Research has been done that really calls into question whether VO2max, lactate threshold, or running economy limit endurance performance in any way.
Alternatively, I have advanced the idea that the true limiting factor in running performance is the muscular system, not the body’s ability to utilize oxygen.
I contend that basing a training program on a flawed theory (VO2max) could very well mean that the training program is equally flawed. In the least the training program would not be designed to optimally improve the factors that limit performance and hence training results would be sub-optimal.
I suggest that muscles are the true limiting factor in running performance and that training programs must be focused on improving muscular power. Numerous studies have shown that high force production training is the best method for accomplishing this. Additionally, research also shows that much less frequency is required than most running programs advocate. I generally recommend 3 – 4 quality workouts per week, based on an individual’s personal rate of recovery. Also, there is no evidence that easy runs promote faster recovery. Instead, as training volume increases so does the number of running injuries.
I hope that this review of the current state of the art in running physiology has proven useful to you and I welcome questions or comments.