Note: Single-source report; awaiting corroboration.
Professor Andy Jones, who has collaborated with athletes including Eliud Kipchoge and Paula Radcliffe, outlined the physiological demands of the endurance events at the World Athletics Ultimate Championship: the 800m, 1500m, and 5000m. He stated these races are predominantly aerobic, though the 800m features a near-equal mix of aerobic and anaerobic energy systems. The 800m and 1500m are more similar to each other than to the 5000m regarding energy contributions.
Jones noted that as race distance increases, athletes tend to be lighter, with reduced muscle mass and higher VO2 max values. This contrasts with the 800m, where athletes often have greater muscle mass to support the balance between aerobic and anaerobic demands.
Training regimens differ by distance, with longer events requiring greater weekly mileage. For instance, 5,000m runners may exceed 70 miles per week at peak. Training can also involve supplementary activities like cycling and swimming to boost speed and aerobic conditioning.
Race tactics change in championship settings compared to Diamond League events, where pacemakers are used. Without pacemakers, those seeking a fast pace must lead early and face greater air resistance, which benefits competitors who draft behind. Air resistance affects both longer and shorter events such as the 800m, where high speed increases drag, but leading can reduce the risk of tripping.
Jones' analysis of Sydney 2000 Olympic 800m and 5000m races showed that winners were not always the fastest on average speed but were those who ran the shortest effective distance, highlighting the importance of efficient positioning and minimizing extra distance covered.