Why is strength training beneficial to endurance athletes? Part 1


I want to open this post by reminding you of the competing cell signalling pathways between enhancing endurance performance versus enhancing strength and power development.  This was covered briefly in my previous post.  Endurance athletes need to enhance what we call their running economy, whilst attempting to improve their VO2 max steadily over time. 


The likely adaptive mechanisms for improvement in endurance from doing strength training with endurance training are an increase in type IIA muscle fibres.  These are less fatigable then other fast twitch muscle fibres and can produce a higher force output.  Additionally with strength training we see a substantial increase in maximal muscle strength (MVC) and rate of force development (RFD).


Importantly, due to the nature of endurance training, which will dominate their training, strength gains are seen without an increase in muscle size (hypertrophy) for these athletes.  So, it’s beneficial because elevated muscle mass is thought to be detrimental for optimal endurance capacity as the extra mass makes it more difficult for the athletes to move from point A to B as efficiently. Think of a marathon runner’s body shape… they’re sleek and toned, without any bulk.


The lack of muscle size also maintains the diffusion distance between the exterior and interior of the muscle cells, thereby not reducing the capacity for glucose and free fatty acids to move from the capillary beds into the working muscle cell. In a nutshell: it’s more efficient. Maintenance of muscle cell size also enables more effective removal of heat, which is a by-product of energy metabolism in the working muscle cell, further enhancing endurance performance.  Interestingly some studies have shown that strength training may actually enhance the formation of new blood vessels (angiogenesis) even in high level athletes, further aiding the supply of oxygen rich blood to the working muscles. 


Most importantly the addition of strength training will not lead to an increase in muscular size, especially if your endurance training volume is moderate to high, while strength gains are still clearly seen.  In subsequent posts on this topic I will discuss how strength training can lead to an increase in rate of force development.  I will also cover what sort of strength training is beneficial to the endurance athlete.


Key take-home points:


1)    Strength training is beneficial to endurance athletes

2)    Strength training can lead to strength gains without a gain in muscle size in endurance athletes

3)    Strength training can enhance Type IIA muscle fibre development in endurance athletes.

4)    Strength training can lead to extra blood vessel development around the muscle in addition to endurance training.


Cheers to movement, strength and wellbeing.




Ross Kinsella