An equilateral triathlon is a

triathlon A triathlon is an endurance multisport race consisting of swimming, cycling, and running over various distances. Triathletes compete for fastest overall completion time, racing each segment sequentially with the time transitioning between the d ...

in which each leg would take an approximately equal time. These triathlons were proposed by Wainer and De Veaux (1994) to redress the bias in favour of

cycling Cycling, also, when on a two-wheeled bicycle, called bicycling or biking, is the use of cycles for transport, recreation, exercise or sport. People engaged in cycling are referred to as "cyclists", "bicyclists", or "bikers". Apart from tw ...

over

running Running is a method of terrestrial locomotion allowing humans and other animals to move rapidly on foot. Running is a type of gait characterized by an aerial phase in which all feet are above the ground (though there are exceptions). This is ...

and particularly over

swimming Swimming is the self-propulsion of a person through water, or other liquid, usually for recreation, sport, exercise, or survival. Locomotion is achieved through coordinated movement of the limbs and the body to achieve hydrodynamic thrust that r ...

in standard triathlons. Cycling occupies about 78% of the typical race distances, running 19%, and swimming 3%. Based on world-record times for similar distances, cycling would take 54% of race time, running 31%, and swimming 15%. In Wainer and De Veaux's equilateral triathlons, cycling should take approximately 33% of race time, running 33%, and swimming 33% for a ratio of roughly 1:8:3.5 for distances of swimming / cycling / running. Examples would be: Wainer and De Veaux's proposal appears to have had little influence on triathlon race distances
Isoman Triathlon
is a triathlon race with distances roughly equal to the stated portion.

References

*{{cite journal, last1=Wainer, first1=Howard , authorlink1=Howard Wainer, last2=De Veaux , first2=Richard D., year=1994, title=Resizing triathlons for fairness, journal=Chance, volume=7, pages=20–25, doi=10.1080/09332480.1994.10542407 /dx.doi.org/10.1002/j.2333-8504.1994.tb01588.x Preprint(

Educational Testing Service Educational Testing Service (ETS), founded in 1947, is the world's largest private nonprofit educational testing and assessment organization. It is headquartered in Lawrence Township, New Jersey, but has a Princeton address. ETS develops v ...

Research Report RR-94-15) Triathlon