Running Research: A Multi-Year Study of World-Class Training Logs

Cutting to the chase:

A 2019 study published in the Journal of Strength and Conditioning Research by Casado, Hanley, Santos-Concejero, and Ruiz (2019) studied the training logs of world and national class runners and determined that the amount of total mileage, easy runs, and tempos were the best predictors of athletes’ race performances during the first seven years of their careers.

Why the study was done:

One of the main purposes of the study was to test the hypothesis that designated practice (DP) exercises are the most beneficial to improvement in performance for a given field. Casado et. al (2019) define designated practice as, “a theory of practice that is conducted with the specific goal of improving performance, and in sports, requires considerable effort, concentration, and enjoyment, and should be considered by athletes as very relevant in improving” (p. 1). In basic terms, DP is any practice that is designed to improve performance and requires a high amount of concentration or effort either physically or mentally. Casado et al. designated tempo runs, long intervals, short intervals, and competitions or time trials as DP activities. Conversely, easy running was not considered DP because the level of concentration and effort reported by the study’s participants was not high enough to fulfill the requirements of DP. The study of designated practice originated with musicians and has spread to other fields, like long-distance running.

The other goal of the study, which is most pertinent to distance runners, was to determine which aspect of training correlated the most with strong race performances.

What athletes participated:

It is worth noting that the first author of this study, Arturo Casado, is a retired Spanish middle-distance runner who had an extremely successful athletic career. He holds personal bests of 1:44 in the 800m, 3:32 in the 1500m, and 3:52 in the mile. Additionally, he earned a bronze medal in the 1500m at the 2007 European Indoor Championships and won gold at the 2010 European Outdoor Championships in the same event. Casado’s athletic career is important because he has a unique perspective on the demands and intricacies of world-class training that is not normally found in most exercise scientists.

What makes this study unique is the quality of runners that participated. Few studies include world-class runners. However, all of the participants in this paper were either national or world-class. Their participation was easier for Casado et al. to obtain because the researchers did not run an active experiment on the runners but instead gathered and analyzed their training from the past. This, in turn, made the willingness and participation of high-level runners increase because it did not require any alteration to their current training. Casado et al. (2019) studied world record holders, Olympians, and global medalists:

“Eighty-five male elite- and international-standard long-distance runners took part. The age range was between 18 and 43 years, with a mean age of 28 years. All subjects were specialists in the 5,000, 10,000 m, half-marathon (21.195 km), or marathon (42.195 km) events … The subjects’ performances ranged from world-class to competitive national standard. Among the best athletes, there were medalists from the IAAF World Cross Country Championships, IAAF World Championships (marathon), Olympic Games, Commonwealth Games, African Championships, European Cross Country Championships, and European Championships (track). These runners’ best times ranged from 2:03:23 (a former World Record holder) to 2:36:15 in the marathon, and from 58:54 to 1:08:48 in the half-marathon; the current World Record holder for the 10-km road race (26:44).” (p. 2)

Though not explicitly stated, it is easy to deduce that the 2:03 marathoner was Wilson Kipsang and the 26:44 road 10k runner was Leonard Komon.


Casado et al. focused on the first seven years of their participant’s careers once they started organized training. In order to standardize performances, they assigned each race a point value based on the IAAF scoring tables. They utilized questionnaires to gather information on the runners’ training and almost all of the runners used a training log to complete it. To complete the study, “Simple linear regressions and associated equations were calculated to analyze the relationships between running performance scores after 3, 5, and 7 years of systematic training (dependent variable)” (Casado et al., 2019, p. 3). Here is a table of how the researchers defined each type of training:

Type Distance/Time % of Max Heart Rate
Easy runs 8km – 40.5km 62% – 82%
Short Intervals 200m – 1000m 95% – 100%
Long Intervals 1000m – 2000m 92% – 95%
Tempo Runs 45 min – 70 min or 1000m – 5000m 82% – 92%
Races or Time Trials 5000m – Marathon 82% – 95%


The total volume of running, or total mileage, had the strongest correlation to performance. Beyond that, easy runs were more predictive of performance than any other activity. The third type of training most correlated to performance is tempo runs. In fact, according to Casado et al. (2019), “the only variables that can be considered predictors of performance were easy runs and tempo runs in all stages and models.” (p. 4). Short-interval training had some predictive capabilities while long-intervals were the most ineffective and time trials and races had no correlation at all.

Why should we care?

The study’s findings point athletes towards emphasizing their mileage over a long period of time. This study analyzed the training of world-class athletes over years of training. As such, it is not a problem to miss a day or have a down week as long as an athlete is generally focused on keeping their volume of easy runs high over the course of an entire training block. Furthermore, tempo runs should be included on a regular basis as they are proven to be one of the most important aspects of training. According to this study, easy runs and tempos should be prioritized over VO2 max intervals for anyone training for races 10k and up.


Casado Alda, Arturo & Hanley, Brian & Santos-Concejero, Jordan & Ruiz, Luis. (2019). World-Class Long-Distance Running Performances Are Best Predicted by Volume of Easy Runs and Deliberate Practice of Short-Interval and Tempo Runs. Journal of Strength and Conditioning Research. 1. 10.1519/JSC.0000000000003176.