It is well known our ability to do physical activity for long periods of time is thanks to efficient energy production in the mitochondria, and that regular endurance training increases numbers in our muscles, and our endurance capacity.
However scientists have discovered that muscle endurance is not only determined by the number of mitochondria, but also their structure.
“We’ve found that mitochondria in endurance athletes are constructed in such a way that they generate more energy than mitochondria in non-athletes. In fact, our measurements have shown us that these mitochondria can generate around 25% more energy. This gives a major advantage in endurance sports such as marathon running and cross-country skiing, but also in ball games like soccer,” says Joachim Nielsen, assistant professor of muscle physiology at University of Southern Denmark.
The scientists examined 15 elite athletes and compared them with 29 people who either did not exercise or were moderately active. All study subjects underwent a muscle biopsy, which was later viewed under an advanced microscope that can detect even the minutest changes in muscle structure.
The scientists say it is still too early to say whether the improved mitochondria in athletes is genetic or whether they are a result of long-term exercise, however they are now working on the hypothesis that training over longer periods of time can induce these kinds of changes in the structure of mitochondria.
“We took detailed measurements of each muscle fibre and saw that those muscle fibres that are typically most active during extended periods of physical activity are also those with the most significant changes in mitochondrial structure. We see this as a clear indication that the athletes have produced these changes themselves through their training,” explains Joachim Nielsen