Wedged between the glorious power of Michael Johnson and the magical mystery of Roger Bannister's anachronistic, yet groundbreaking moment, is perhaps the grittiest and most cruel of all track and field events: the 800 meters. All apologies to 400-intermediate hurdlers. A foot to the grind, if you will.

What is the 800 meters? For one, it's 874.89 yards. Two laps. One turn stagger-which means runners break for the pole from their assigned lanes after the first turn and beeline it for lanes one and two on the backstretch. But what is it in a physiological sense? Many exercise physiologists consider it to be a hybrid event.

An undertaking possessed of a split personality, with aerobic and anaerobic sources downloaded equally.

Generally speaking, there are three types of energy systems: aerobic, lactic anaerobic, and alactic or ATP-CP. “The 800 is a near sprint for two laps which is high intensity and very physically demanding requiring both speed and endurance,” said Dana Mecke, a Texas-based runner who recently competed in the women's 800-meter final at the USA Track and Field Championships. “I come to the 800 from the distance side so to me the 800 feels a lot easier than the 1500. I have only run the 400 a handful of times on relays, but to me the 800 is more intense than the 400.” Bob Westman, the sprints and hurdles coach at the University of Toronto, might concur with the aforementioned exercise physiologists, though he insists that any information he provides is based on his philosophy and beliefs.

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“I’ve heard many different 'opinions' on the energy systems in play in an 800. I’ve seen as low as 30 percent aerobic and as high 60 percent aerobic. I’ve always preferred instead to think of it as a symbiotic relationship between speed and speed reserve. The faster you are, the more leeway you have to run at a lower percentage of your max velocity. And conversely, the greater your speed reserve, the longer and closer you run near your top speed. Maximizing both of those characteristics will allow the 800 runner to see their fastest times.”

Marina Arzamasova, the Belarusian runner who won the women's 800-meter final at the 2015 International Association of Athletic Federations (IAAF) World Track and Field Championships in a time of 1:58.03-well behind Jarmila Kratockvilova's suspect 1983 world record of 1:53.43-ran what are called negative splits (when the first lap is slower than the second), in 59.15 and 58.88. Would she be classified as a runner with ample speed reserve? Most likely.

However, in the men's 800 meters at the 2015 IAAF World Championships, the unrivaled Kenyan, David Rudisha, breezed to glory in a sun dial time of 1:45.84-well off of his super human world record of 140.91-with negative splits of 54.17 and 51.67. The discrepancy in his splits indicated that his ability and training allowed him the luxury of running well under his maximum velocity until the deal had to be closed. Then he shifted gears.

What is it about the training in this event that separates the 800 from other track and field specialties? The anaerobic factor. This portion of an 800-meter runner's training is the most grueling and onerous. “This is where the 400/800 meter programming will differentiate from a short sprinter,” stated Westman. “There are an infinite amount of different workout combinations, and they’re all nasty! The intervals are meant to challenge the runner with incomplete rest while working at a pace where fatigue accumulates faster than recovery.” Mecke echoes the sentiment. “I would say the training is pretty tough. A typical week would consist of three hard interval practices, one tempo run day, one long run day, and easy mileage runs where I average about 55 miles per week.”