Ever thought that your body is just not capable of running a marathon? Science may be here to back you up. We spoke to Dr Ryan Harvey to find out more.
A study conducted by experts from Exercise Physiology Laboratory has analysed the influence of genetics on muscles ability to run marathons. They determined that some athletes genes make their muscles more prepared to run marathons than others.
What marathon running does to your body?
Running a marathon, as some of you may know, involves a great deal of physiological commitment.
“Running a marathon requires the respiratory, cardiovascular and musculoskeletal systems to work overtime,” says Dr Ryan Harvey, a home doctor with House Call Doctor.
Getting across that finish line is no easy feat and can cause lasting muscle damage. For some that burn is affirmation that their goal is in reach. For others it signals time to slow it down and take a rest.
“Your body goes through a tremendous amount of stress during a marathon race,” says Dr Harvey.
“Some typical symptoms of athletes may included exercise-induced rhinitis, weight loss of up to 2 – 5kgs of fluid, damage to blood vessels in the feet, muscle soreness and microscopic muscle tears.”
Researchers from this study commented that a marathon requires 30,000 strides, with runners legs absorbing between 1.5 and 3 times their body weight with each step.
“The constant contractions of leg muscles during a marathon leads to progressive deterioration in muscle fibres,” says Dr Harvey.
However, not every athlete crosses the finish line with the same level of muscle inflammation or damage. Some have low levels of muscle deterioration while others have profound levels of muscle pain.
Why do some experience more muscle soreness than others?
These differences can be seen even when athletes have had the same level of intensive training leading up to the race.
Researchers in this study aimed to answer why some cross the finish line with less muscle damage than others, regardless of preparation.
The repetitive movement of leg muscles has two consequences:
- The damage caused to muscles results in the lack of ability to produce strength. This is seen when runners collapse at the finish line or faint mid race.
- The proteins of injured muscles are released into the blood stream. This allows us to measure the damage through analysing the creatine kinase or myoglobin levels of a blood sample.
“Creatine Kinase and Myoglobin are proteins which are required for proper muscle functioning,” says Dr Harvey.
“A higher level of these proteins in a blood sample means there is greater damage caused to the muscle fibres.”
This study focused on 7 genes that relate to muscle function, scored from 0 no muscular advantage to 2, positive advantage. They determined that athletes with a higher genetic score of these 7 genes had less damage to their muscles post run.
The future of marathon running
While this news may be both reassuring and disheartening for some it is not to suggest that those who have lower scores should not run marathons.
Genetic profiling for marathon runners
Instead it opens the doors for the future of genetic profiling in marathon training. In the future these tests may be utilised to assist with training plans. Having a less favourable genetic profile does not mean some should not complete, but instead they may need to do specific training to prepare their muscles.
“Performing genetic profile testing on athletes may assist in the direction of their future training,” says Dr Harvey.
“Those with less favourable genetics will need to adapt their training regime to allow for this extra stress their muscles will be under.”

Amy Darcy


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