Study aim: To analyse the distribution of effort in the 800 m event at the IAAF World Athletics Championships in London 2017 (outdoor, 44 men, 45 women) and in Birmingham 2018 (indoor, 9 men, 14 women). Material and methods: A total of 187 individual performances during heats, semi-finals, and finals were analysed. The official split times of each athlete every 100 m were taken as reference for the analysis of: times; percentages of times in regard to the final time; speed; changes in position during the races; percentage deviations in terms of the average time per race per section of 100, 200 and 400 m. Results: There are different strategies used in the elite 800m race that are related to sex differences, the management of energy consumption and the differences and similarities between indoor and outdoor races. Conclusions: Although diverse pacing strategies exist, more balanced strategies, after a fast start, have better results.