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There are many ingredients in the recipe of running fitness.
Scientists at Georgia State University tried to determine the relative contributions of several key attributes to running performance. The results suggest that running performance is a puzzle of many pieces, and that no two runners attain any given level of performance with precisely the same physiological recipe.
Thirteen female collegiate cross-country runners were subjected to a test of anaerobic capacity, as well as tests of running economy (how much energy is required to sustain a given running speed), maximum speed in a 50-meter sprint, ventilatory threshold (the running speed at which a sudden spike in the rate of oxygen consumption occurs), and aerobic capacity (or VO2max—the maximum rate of oxygen consumption). The thirteen runners also ran 5 km time trials on a 400-meter track. The researchers then compared the data from each of the measured attributes against the 5 km times to determine which attributes had the greatest impact on performance.
Not surprisingly, aerobic capacity was found to have the strongest correlation to 5K running performance. The strength of that correlation was 0.80. A correlation of 1.00 would have meant that VO2max alone accounted for all of the variation in race times. The second greatest contributor was velocity at maximum anaerobic capacity. A test of anaerobic capacity is a short, very high-intensity run in which runners are required to burn energy at a faster rate than their aerobic capacity alone can support. The extra energy comes from anaerobic metabolism. The researchers found that the speed that the runners reached in the anaerobic capacity test had a 0.69 correlation with 5 km run times.
The third-strongest determinant of 5K performance was ventilatory threshold, or the speed at which the runners started sucking wind. Together, VO2max, velocity at anaerobic capacity, and ventilatory threshold accounted for 81 percent of the differences in 5K times among the thirteen women in the study. While that’s a pretty big influence, it still leaves 19 percent of performance to be accounted for by other factors.
What are these other factors? Two of them were also included in this study: maximum sprint speed and running economy. Although these two factors had the weakest correlations with 5 km running performance in this particular study, there was an influence, and other research has shown that both raw speed and efficiency are important ingredients in the running performance recipe.
There are still more attributes that contribute to running performance. Body composition is one that is often overlooked. Everyone knows that the best runners are skinny and light, but research suggests that even very small differences in body fat levels among very lean and fast runners account for differences in race performance is fully as differences in VO2max do.
Even factors as arcane as leg stiffness have been shown to discriminate between better and lesser runners. Although it sounds colloquial, “stiffness” in this context is a scientific term that refers to how much the joints of the lower extremities give when a foot makes contact with the ground during running. Less give translates into a bouncier, more efficient stride. Strength training has been shown to increase leg stiffness and running economy, which a high degree of flexibility in the hamstrings is associated with less stiffness and lower running economy.
The list goes on. Heat dissipation capacity, pain tolerance, and a variety of stride characteristics such as ground contact time are among many more attributes that cannot be excluded from the running performance equation. The very exercise of trying to create an exhaustive list of factors influencing running performance threatens to become overwhelming. How can a runner possibly work on all of them?
Fortunately, most of the factors that influence running performance are most effectively strengthened through two measures: running slowly and running fast. Running slowly increases VO2max, reduces body fat, enhances running economy, and raises the ventilatory threshold. Fast running further increases VO2max and running economy while also boosting anaerobic capacity and pain tolerance and preserving raw speed. The right balance of slow and fast running will do almost everything that can be done to make you a better runner. A little strength training completes the puzzle of running performance.
There is some fine print, however. What’s comforting about research like the Georgia State study I’ve just described is that it shows there are many paths to better performance. You’re not automatically sunk as a runner just because you lack raw speed or have poor running economy. But what is also suggested by such research is that each runner has at least one relative weakness—at least one performance-relevant attribute that is not as strong as it is in most runners of equal ability. The surest opportunity for improvement as a runner, then, is to make an effort to identify one’s relative weaknesses and work on them.
While it’s generally true that effective training for all runners is nothing more than a balance of fast and slow running, the right balance is different for runners with different weaknesses. Also, there are specific types of fast and slow workouts that are best for addressing particular weaknesses. For example, if muscular strength is your weakness, you may need to do more hill repetition workouts than a runner who is naturally stronger. If raw endurance is your weakness, you may need to put more emphasis on long runs than other runners of equal ability.
I doubt we will ever completely solve the puzzle of running performance. But the never-ending journey of trying to solve one’s individual puzzle is half the fun of being a runner.
About The Author:
Matt Fitzgerald is the author of numerous books, including Iron War: Dave Scott, Mark Allen & The Greatest Race Ever Run (VeloPress, 2011). He is also a Training Intelligence Specialist for PEAR Sports. To learn more about Matt visit www.mattfitzgerald.org.