Triathlon discipline
Middle Distance (70.3)
Middle distance triathlon, widely known as 70.3, covers a 1.9 km swim, 90 km bike, and a 21.1 km half-marathon run.
Overview
Middle distance triathlon typically comprises a 1.9-kilometre swim, a 90-kilometre bike leg, and a 21.1-kilometre run, the last of which is a half-marathon.
It is popularly known as '70.3' after the combined legs totalling roughly 70.3 miles, a name associated with the Ironman 70.3 series.
It sits between the shorter Olympic distance and the full long distance, emphasising sustained endurance over several hours.
What defines it
- Approximate distances are 1.9 km swim, 90 km bike, and 21.1 km run (a half-marathon).
- The '70.3' name refers to the roughly 70.3 total miles of the combined legs.
- Steady pacing and a nutrition strategy matter across a race that usually lasts several hours.
- It is often approached as a stepping stone between Olympic distance and full long-distance racing.
Getting started
- 1Develop consistent endurance in swimming, cycling, and running before combining them over longer sessions.
- 2Many athletes complete shorter formats such as sprint and Olympic distance first.
- 3Review the specific event's course profile and cut-off details, since these vary between races.
Other Triathlon disciplines
The forms of Triathlon sit alongside each other — explore the rest.
Explore across the knowledge base
Follow the threads that connect Middle Distance (70.3) to the rest of SocialSportHub.
Sports
- TriathlonA multi-sport endurance event that links swimming, cycling and running into one continuous race.
- Ultimate FrisbeeA fast, non-contact team sport played with a flying disc, known for constant running and self-refereeing.
- TaekwondoA striking martial art known for its dynamic kicking techniques, agility and structured progression.
- Indoor CyclingAn energetic, low-impact studio workout on a stationary bike, guided by an instructor and music.
- Mountain BikingAn off-road cycling sport ridden on rugged trails, mixing endurance, bike handling and outdoor adventure.
Rules
Techniques
- Freestyle StrokeThe fastest swimming stroke, using alternating overhead arm pulls, a flutter kick and rhythmic side breathing.
- Cycling CadenceThe technique of pedalling at a smooth, steady rhythm and choosing a gear that keeps the legs turning efficiently.
- Running FormThe efficient posture and stride mechanics of distance running, keeping the body relaxed and the cadence smooth.
- Inside-of-the-Foot PassThe most reliable short pass in football, played with the inside surface of the foot for accuracy over a short to medium distance.
- BreaststrokeA swimming stroke with a simultaneous arm sweep, a whip-like frog kick and a glide, performed on the front.
Playing surfaces
- WaterThe medium for aquatic sport — pool or open water that supports the body with buoyancy and resists movement with drag rather than giving footing.
- Road (Tarmac / Asphalt)Paved tarmac or asphalt: a firm, smooth, predictable surface that rewards steady pace and rhythm — the ground for road running, cycling and race-walking.
- GravelLoose crushed stone over a firm base — an unpaved middle ground between smooth road and rough trail, ridden and run for variable grip and steady pace.
- Synthetic trackAn all-weather rubberised athletics running surface — firm, springy and high-grip — giving sprinters and distance runners fast, consistent, predictable footing.
Scoring systems
- How running races are timed and placedRunning races are decided by finishing order and by elapsed time, measured precisely and settled by the moment a runner's torso crosses the line.
- How swimming races are timed and placedSwimming races are decided by elapsed time and finishing order, with electronic touchpads recording when each swimmer completes the distance.
- How fitness progress is trackedGeneral fitness has no formal scoring, so progress is tracked through measurable markers such as repetitions, load, time, distance and personal bests.
How this page is maintained
- Content type
- Discipline
- Provenance
- Tier A — evergreen educational
- Verified external sources
- 0
- Content updated
- 2026-07-09
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Triathlon