While traditionally VO2max has been considered the determining factor in endurance running performance, recent studies have suggested that running economy is in fact the most important variable. Run Ireland notes that many top athletes win competitions with only an average VO2max but a high running economy. An example of the leverage given to running economy is illustrated in a study conducted on highly trained athletes during a 10k race. As the athletes had very similar VO2max scores, the 65.4 percent variation in performance could be attributed to running economy.
Running economy is a measure of efficiency and is calculated by the volume of oxygen relative to body weight that the body needs to run at any given speed. Someone with a high running economy has a lower energy demand and therefore requires less oxygen to maintain a faster speed.
The importance of running economy increases with the distance of a race, as athletes with more efficient running economies are able to run faster without intensifying energy expenditure. In this way, running economy has the biggest impact on long-distance endurance events.
Improving Your Running Economy
There are certain identifying factors that influence running economy which can be used to help develop a training plan. According to Intelligent Triathlon Training, a number of internal and external factors exist. Internal factors include fitness level, mental state, fatigue, strength, running style and tendon stiffness. External determinants may be excess weight and shoe cushioning, weather, altitude and surface type.
Although the best way to improve economy is disputed, several methods are generally agreed to be beneficial by scientists and endurance sports coaches alike. As highest economy is found in experienced athletes who have accumulated many miles throughout their training, running long distances was originally the recommended practice; however, this can put inexperienced athletes at the risk of injury. Studies conducted by Daniels and Bransford et al respectively support the claims that the largest improvements are gained by strength training, altitude exposure, and training in warm or hot climates.
Strength training is the easiest variable to work on for most runners around the world, as it does not involve seeking out places of high terrain or environments of higher temperatures in order to train. Although many endurance athletes are deterred from resistance training due to the belief that it leads to negative effects such as weight gain and a decrease of aerobic fitness levels, studies have shown that neither VO2max nor lactate threshold (anaerobic threshold) are compromised when used in conjunction with endurance training.
Explosive strength training is generally considered the best technique to improve running economy. Among others, a study conducted by Paavolainen et al, showed an 8.1% improvement in economy after nine weeks training. This translated to an average of 3.1% percent improvement to 5k run times, while no effects were seen on lactate threshold or VO2max.
Given all the evidence, it seems clear that running economy has a profound effect on endurance performance. As such, athletes trying to improve endurance performance may want to focus on improving running economy by incorporating strength training exercises into their workout regimen.