Fatigue is the enemy in training. It destroys skill work. It eliminates explosiveness. It cuts endurance. Fatigue is our enemy. This is why such an emphasis on training and recovery needs to occur in the preparation of any athlete.

Until now, our way of measuring fatigue has been rate of perceived exertion- basically asking from 1-10 how tired are you? If one were a smarter coach, they would also ask 1-10, how recovered are you from our last session –forcing the athlete to consider the overall training arc.

Michael, et al. 2012 has gone far beyond this. Using 9 recreationally trained cyclists they simulated 10h of activity. Upper body exercise, lower body exercise and cycle ergometery were all performed. Each hour of the study, saliva swabs were taken and analyzed for two peptides. The ratio of these peptides appears to accurately reflect the level of fatigue the athletes were reporting P<.05

The same lab performed another experiment in 2011. Kalns, et al. 2011 completed a survey of participants entering the elite US Air Force tactical air combat controller training pipeline. The training is approx. 20 months long with a failure rate of 80%. The goal of the study was to monitor various physiological and psychological variables to see what could be used to determine successful completion of the course in future classes.

126 candidates had 55 variables collected divided into 5 broad categories; 1- demographic, 2- psychological compositions, 3- physical performance, 4- physical activity questionnaire and 5- salivary biomarkers for fatigue (as the above study did for the cyclists).

Of these 55 variables, 4 variables were found to predict successful completion of the course. Total runtime for a 1.5 mile course, average weekly miles run for the last year, height and the fatigue biomarker index. In fact, the ideal candidate with the greatest chance of passing the program could run 1.5 miles in under 10.4 minutes, ran >8.5 miles/week for at least 1 year, had a biomarker rate of less than 3.5 (or greater than 103 depending on units) and was at least 71 inches tall- they would very likely complete the program.

This particular program was only during the initial indoctrination portion of the training cycle or 13.5 weeks. During that time period 48.3% of applicants failed. If these 4 criteria had been applied to the group beforehand, it was determined that failure rate would have been 23%. Thus this combination can predict half of the failures in the indoctrination part of the program! Given that height is fixed in adulthood, 1.5 mile run time is easily obtainable (particularly in the military), previously run weekly distance is easily checked in training logs and saliva swab analysis is not out of reach of most people- tests of this nature can predict physical and mental resilience and be easily implemented. For those interested, Hyperion Biotechnology is the company who owns the lab where the saliva analysis is done. Should you wish to determine if you are fatigued and what you need to do to recover properly, I’m sure these guys can help.