What is Endurance?

Endurance can be defined as the ability to withstand stress over prolonged periods of time. An endurance sport is therefore any sport in which there is a prolonged physical stress.

Endurance Sport Requirements

The main requirement is the ability to sustain a fast pace over a prolonged period, without sustaining undue fatigue through the build up of lactic acid. Events of greater than 800 m are mainly aerobic, with an increasing aerobic demand as duration increases. The main aerobic source of energy is through the metabolism of carbohydrates (glycogen) and fats in the form of free fatty acids. Energy is also supplied from the anaerobic metabolism of glycogen to form lactate and an initial 4-6 seconds supply comes form the intra-muscular store of high-energy phosphates.

Aerobic and Anaerobic Energy Sources

In the 1500m, 5km, 10km and ½ Marathon events the contribution of aerobic and anaerobic energy sources are approximately; 80% and 20% in the 1500m, 95% and 5% in the 5km, 97% and 3% in the 10km, and 99% and 1 % in the half Marathon respectively (Maughan et al., 1997; Fallowfield and Wilkinson, 1999). Despite being small the anaerobic contribution may make a significant contribution to the relative exercise intensity sustained during the 1500m and 5km events (Fallowfield and Wilkinson, 1999) and even during longer races such as the ½ Marathon it may come into play when working hard up a hill, during mid race surges or during a sprint finish. However the majority of a middle/long distance athlete’s training time would be devoted to developing and maximising their aerobic capacity and efficiency.

An athletes level of ability, as an endurance athlete, will be determined by a number of key physiological components. These key components include:


Fallowfield, J.L. and Wilkinson, J.L. (1999). Improving sports performance in Middle and Long-Distance Running. Chichester: John Wiley and Sons, LTD.

Maughan R., Gleeson M., and Greenhaf P.L. (1997). Biochemistry of Exercise and Training. Oxford University Press, Oxford.