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You can't win a triathlon race while swimming…,
but you can easily lose it…

Energy efficiency in triathlon

A webinar from January 28, 2014 with Mike Joyner, Bobby McGee, Terry Laughlin, Suzanne Atkinson, etc. organized by Triathlon Research

Swimming in triathlon presents other challenges than just a swimming race. Triathlon is in fact an energy management puzzle.

  • Swimming 2 miles/h (~3.2 km/h)

  • Running 8 miles/h (~13 km/h)

  • Cycling 20 miles/h (~32 km/h)

has about the same energy cost for athletes who are about as skilled.

Mike Joyner:

Increasing the oxygen cost for each branch by 10% costs approximately

  • Running + 10%

  • Cycling + 25-30%

  • Swimming + 60-80%

In a typical triathlon race, the gap between a top athlete and an average is calculated in oxygen cost to get there at the same speed

  • Cycling 15%

  • Running 20%

  • Swimming 200-300%

The conclusion you can draw is that the biggest improvement for cycling and running is to increase the amount of exercise. But in swimming, it is an efficiency improvement that significantly improves performance.

An easier way to measure efficiency

Mike Joyner:

While there is no practical way to measure oxygen consumption, the following insight can be practical: “What in most cases distinguishes an Olympic gold medalist in swimming from those who do not win in the same race is that the winner can keep the same number of arm strokes per length even when fatigue strikes ”.

Bobby McGee:

This is in contrast to running, where the opposite is true, namely that the elite shortens the stride length slightly and keeps or increases the pace when they get tired, while mediocre runners try to keep the stride length and slow down the pace when they get tired.

To take with you to triathlon swimming

  • Minimize the oxygen cost, ie end the swimming with a low heart rate

  • Start swimming with a long, relaxed arm stroke and finish in the same way, ie take control of the arm stroke tempo (where Tempo Trainer is an invaluable imprinting tool)

Michael J. Joyner , MD, is a physician-researcher and one of the world's leading experts on human performance and exercise physiology.


Bobby McGee is an internationally certified track and field coach whose athletes have produced world records, won world championships, and been consistently ranked amongst the best in their events. He coaches runners and triathletes, and has worked with USA Triathlon preparing athletes for ITU World Cup races and the Olympic games from 2004 to 2012.

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