Training

 

Resistance Training for Runners - Bonus Section

 

Bonus Section: For those who want to explore a bit further, this section delves into the reason why resistance training improves endurance performance.

The current paradigm in endurance training is that performance is controlled and limited by factors in the aerobic energy system.  Typically researchers, coaches, and athletes refer to factors such as VO2max, lactate threshold, and running economy to explain and predict performance in endurance events.

However, this paradigm is severely challenged by research showing an improvement in endurance performance due to resistance training.  The physiological changes occurring as a result of resistance training are quite different from those changes that occur due to endurance training.  Resistance training typically causes increased muscle fiber size, decreased mitochondrial density, no improvement in capillary density, and other changes that are NOT associated with improved endurance performance.  This brings up the question of exactly how resistance training causes improvements in endurance performance since it either doesn’t improve or actually causes an opposite response in those physiological factors associated with endurance performance.  There doesn’t seem to be an adequate explanation that fits with the cardiovascular/anaerobic model of endurance performance.

If we set aside the belief that endurance performance is controlled by aerobic factors then there is a logical explanation for improvements in endurance performance due to resistance training.  The explanation is muscle power.  As I wrote in the “muscle contractility” series posted elsewhere on this web site, all endurance performance is primarily influenced by three muscle factors - strength, max contraction speed, and resistance to fatigue.  These three factors are more important in performance than any other factors, including VO2max, lactate threshold, and running economy.  It doesn’t matter if you are running 50 meters or 50 miles; these three factors are the most important in performance.  If you improve any of these three factors performance will improve.

Note though that the relative influence of these three muscle factors is not equal at all running distances.  Depending on the distance you are running, they exert different levels of influence on performance.  Muscle fiber contraction speed is the most important factor in sprint performance.  Resistance to fatigue is the most important factor in long distance running.  Resistance to fatigue plays a much less prominent role in the 100 meter sprint than it does in an ultra-marathon.  Conversely, muscle fiber contraction speed is very important in the sprint, but becomes less important as the racing distance increases.  Strength is important at all distances, but exerts its highest level of influence at short to middle distances, say 400m to 5km.  All three factors taken together exert the most influence on performance, but all three factors do not exert the same amount of influence at all distances.  So, all three are important, but not equally important for every running distance.

This brings us to resistance training.  We know that resistance training increases muscular strength.  An increase in muscular strength causes an improvement in endurance performance, especially at racing distances where strength exerts the most influence.  Strength training is important to sprinters and middle distance runners (that’s why sprinters weight train – it improves their performance) and increases in strength will cause an improvement in performance. 

Combining all these facts explains why resistance training improves endurance performance.  Endurance performance is most influenced by the three muscle factors.  At short and medium distances, strength plays a greater role in performance.  Since resistance training increases strength levels, we are rewarded with an improvement in performance in short to medium distances, just as the research shows.  At longer distances strength is less influential on performance and increases in strength cause smaller improvements in performance, again as research indicates.  This is not to say that strength becomes unimportant at long distances, only that it is less influential on long distance performance than it is on shorter running distances

Summary

The muscle power model of performance logically explains why resistance training improves endurance performance.  Endurance performance is primarily influenced by three muscle factors – strength, max contraction speed, and resistance to fatigue.  An increase in any of these factors results in an improvement in performance.  Resistance training increases muscular strength and therefore improves endurance performance.  All three muscle factors do not exert the same level of influence at all running distances, with strength exerting its highest level of influence at short to middle distances.  This explains the observation that strength training affects short and middle distance performance more than it does long distance performance.