According to the author of ‘The Sports Gene’, David Epstein, if you were to measure every runner’s ankles at the start of a long distance race, you could statistically predict the likely winner. Winners of any major long distance race tend to possess particular body features. Let’s run through some of these physical attributes that are distinctive in top East African runners and appear to give them the edge.

Long tendon, short muscle combination
Sano et al. (2012) investigated the lower leg morphology and behavior of 10 world class Kenyan distance runners and found that the group of athletes possessed a musculo-tendon morphology that is “optimized to favour efficient storage and recoil of elastic energy”. This is facilitated by a significantly long achilles tendon and a short  gastrocnemius calf muscle. As a result, there is a high shortening to stretch ratio of the achilles/gastrocnemius. Meaning that a high degree of kinetic energy is stored upon lengthening, minimal ground contact time reduces dissipated energy, and then a high degree of contraction to created ground force.

Stretch shortening cycle

Thin ankles and calves leg muscle mass distribution
Thin ankle girth and small calf muscles so that the region requiring the greatest torque to move mass has a light load. Heavier mass which contributes greatest to force production is located closer to the pivot point or point of rotation, the hip joint. This distributes mass optimally for running. Would you rather carry 1kg weight around your hip or around your ankle? The upper body follows a similar pattern. 








Long legs, relatively short torso
For stride lengths & efficient mass distribution where rotational points close together.

Narrow pelvis
Less torque required to return feet close to the center line where center of mass can be best displaced during linear movement.

Large surface area relative to body volume
Highly exposed skin surface area relative to the content which produces and retains heat. Results in heat dissipation. For Eskimos this would be a disadvantage and energetically unfavorable.

surface area to volume ratio

Low body fat percentage
As a reference point, a healthy elite marathoner with 3% body fat is estimated to have more than sufficient stored potential energy to last +4 marathons. That is if the body was able to run solely rely on fat and the implications of exercise weren’t physiology overwhelming. Low body fat allows little unnecessary mass to be carried.

Low total body mass
Less carried mass requires less force to displace body, a basic formula which supports fast velocity running. A combination of mass that creates power output, and lack of mass the minimizes the cost of running. Also, l
ighter mass places less loading forces on tendons, ligaments, and bone during training, likely assisting training longevity. 

As the event distance increases from 800m through to marathon, median height decreases. Height however has the greatest quantitative morphological range across parameters, and non-mean values can have offsetting benefits or no ‘disadvantage’. However, typically African elite marathon runners are below the average human height.

While we’re pondering over elite runner’s physical makings, take a look at these interesting pictures which were circulating on twitter recently. They reveal horizontal striation along the rectus femoris muscle, even though muscle striations (fiber alignment) runs vertically. Full explanations to what’s going are yet to be confirmed.

marathoner runners



  • Hi,


    I’m a Biomedical Scientist and I have never seen striations of the Rectus Femoris muscle that are perpendicular to the direction of force (i.e., Eliud Kipchoge’s RF in the swing phase). Could you please indicate whether these striations are muscle fibres or fascia.

    Thank you for your help and kind regards,

    Michael Sinclair

  • Because of political / economic disparities, other high altitude marathon runners are not competing. Such as Andean peoples and peoples in the mountains of Mexico. I wonder what their contributions to sport and physiology would be if they were included

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