Lambert Edgin utilizes his fast twitch muscle fibers to race past his opponents on May 13, 2023, at the University of Virginia, in Charlottesville, Va. Photo used with permission from Marry Ann Magnant.

Hundreds of muscle fibers and different muscle groups work together to perform long-lasting, explosive strides. However, not everyone has the same explosive experience when running. Good health, physical fitness and sufficient running techniques all contribute to a fast runner, but one of the main sources of speed points back to genetics. 

“Usain Bolt is the fastest runner in the world due to the fast twitch muscles in his genetic makeup,” said anatomy and biology teacher David Bostic. “[Fast twitch muscle fibers] are built for short, powerful bursts of energy, whereas, the slow twitch muscle fibers provide high endurance and a slow contraction speed.”

Short distance runners have an abundance of fast twitch muscle fibers that lead to success in short distance events, such as the 100m, 200m and 400m. Long distance runners, on the other hand, are generally made up of slow twitch muscle fibers that benefit them in long distance events like the 5k. 

“If an individual is genetically made up of short muscle fibers, they are still able to train select fast twitch muscles to excel at fast distance events. [However], they will likely still be at a disadvantage,” said Bostic. 

Optimal performance in running depends on a variety of factors. Training intensity, nutrition, flexibility and motivation are all factors that a runner can control; however, other factors like an individual’s maximum oxygen intake, muscle fiber type, strength of bones and tendons, metabolism and overall endurance potential are all significant in the success of a runner. 

“Genetics determine how fast [a runner] can improve, but in most cases, the person who puts in substantially more work will be more successful,” said senior XC and track runner Lambert Egdin. “It’s a mix of both hard work and genetics at the same time.”

According to Lambert, hard work and dedication is the most important aspect of running, but genetics still provide a heavy advantage. 

“Genetics definitely play a major role in running. Ideal genetics can allow an individual to progress much faster and overcome them with significantly less practice or effort than a runner who frequently trains but doesn’t have ideal genetics,” said junior Evan Garbarczyk. 

Ethiopian and Kenyan runners make up 98 of the top 100 marathon performances of all time, according to toolboxgenomics.com. This suggests that environmental and cultural factors along with optimal genetics lead to success in runners. 

“I think someone with poor running genetics can still make it pretty far, but they definitely can’t be world class,” said Evan.