The 40th anniversary of the London Marathon takes place on Sunday, October 4 2020. Athletes will run on a closed-loop circuit round St James’s Park earlier than ending on The Mall. This yr’s lineup contains present champions Eliud Kipchoge and Brigid Kosgei. These athletes can run for greater than two hours at speeds a median individual might preserve for less than a matter of seconds. So what makes them so quick?
Years of coaching have caused bodily variations that allow elite endurance athletes to carry out on the prime of their recreation. Let’s first take a look at the all-important cardiovascular system, which is tailored to allow a daily provide of oxygenated blood to the working muscle tissues.
Robust coronary heart
Common coaching ends in a rise within the thickness of the muscle forming the guts wall, specifically, the left facet of the guts. That is the facet of the guts accountable for circulating oxygenated blood across the physique and to the muscle tissues throughout train.
Elevated thickness of the left ventricle wall (the decrease chamber of the guts), permits endurance athletes to pump extra blood out of their coronary heart every time it beats. We name this the “stroke quantity”.
A daily grownup, exercising at their most stage, can have a stroke quantity of 120ml. Nonetheless, due to the elevated thickness of the guts wall, endurance athletes have a stroke quantity throughout maximal train of round 200ml.
An endurance athlete’s coronary heart can beat 200 instances each minute throughout maximal train, leading to these athletes having the ability to flow into near 40 litres of blood across the physique each minute. The quantity of blood the guts pumps in a single minute known as cardiac output. In elite endurance runners, it may be practically twice that of a median grownup throughout maximal train.
It isn’t only a sturdy coronary heart that’s key to those athletes’ success. Getting sufficient oxygen to the working muscle tissues can be very important.
Actions lasting longer than a few minutes primarily depend on cardio metabolism (the method by which we use oxygen to show gas, similar to fat and sugars, into vitality), making a continuing provide of oxygen essential to success. Elite marathon runners can breathe round 200 litres of air per minute throughout maximal train. This mixed potential of the lungs and coronary heart to absorb and transport oxygen implies that elite athletes have a really excessive VO2 max – the utmost quantity of oxygen the physique can use in a minute. VO2 max is thought to be one of many key determinants of endurance efficiency success.
VO2 max values in a median grownup are round 30-45 millilitres of oxygen per kilogram of physique weight per minute. However in elite endurance athletes, VO2 max will increase to 65-80 ml/kg/min.
Operating financial system
It’s not solely the dimensions of an athlete’s engine (VO2 max) that’s necessary for fulfillment, similar to a automobile, the financial system of the engine additionally performs an necessary position. Most marathons are run at round 75-85% of VO2 max, which means the flexibility to work effectively at decrease train intensities can be key to success. In working, that is measured by “working financial system”.
Athletes with good working financial system want much less oxygen to run at a given velocity than their opponents, preserving very important vitality for later within the race. Elite endurance runners show extremely low working financial system values, displaying their potential to maneuver at quick speeds whereas utilizing a a lot decrease quantity of oxygen than the common individual.
At a given velocity, a median individual could usually want 220ml of oxygen per kilogram of physique weight to run one kilometre. Elite marathon runners are extra economical, maybe requiring as little as 180ml of oxygen per kilogram of physique weight to cowl the identical distance.
An necessary consider working a quick marathon race is the flexibility to run on the quickest attainable velocity with out turning into drained. This optimum velocity or “threshold” is expounded to a number of adjustments that occur in our physique as we train, together with the build-up of chemical compounds within the blood. Blood lactate is one such substance that accumulates within the blood throughout train.
Lactate threshold is a time period utilized in train physiology to explain particular adjustments (or breakpoints) to this substance throughout train.
Blood lactate is usually incorrectly considered a waste product and mistakenly considered accountable for muscle fatigue, however it’s now recognised as an necessary vitality supply. Nonetheless, train above the lactate threshold is related to extra fast fatigue and, as such, the velocity at lactate threshold is a robust predictor of endurance efficiency.
A better lactate threshold will allow the next working velocity to be sustained with out blood lactate accumulating, enabling the working velocity to be maintained for an prolonged interval. Elite female and male marathon runners have reported lactate threshold speeds of 18-21km/h
Because the runners lap St James’s Park on Sunday, all of the above components will contribute to their success – they would be the key determinants of the runners’ efficiency.