Improving your 40km PB is not only about fitness, but also your efficiency of movement says expert Garth Fox.

Anyone watching Bradley Wiggins storming to victory on the streets of south west London in the 2012 Olympic time trial can’t fail to have been impressed by the smoothness of his pedalling action. When you consider that he was applying more force to the pedals for 50 minutes (approximately 490 watts) than most amateur cyclists can manage for one minute, you get an idea of just how accomplished a cyclist he is.

That and the fact he did it with very little superfluous body movement, even at very high power outputs. Less unnecessary movement means that more of his energy is being converted into mechanical work. This all contributes to Wiggins’s high level of gross mechanical efficiency, or the relationship between the energy he puts in and the power he’s able to get out. Greater gross mechanical efficiency means greater bike speed, which is why leading sports scientists advocate training geared towards improving it. In other words, getting the most bang-for-buck from every pedal stroke is the aim of the game.

There are many variables that contribute to cycling performance but the three most important ones for a sports scientist evaluating a cyclist’s physiology are maximal aerobic capacity, lactate threshold and gross mechanical efficiency.

Maximal aerobic capacity is a measure of an athlete’s maximal ability to take in, transport and use oxygen within the muscles. This sets your upper limit for cardiovascular fitness. Lactate threshold describes the exercise intensity at which the release of lactate into the blood exceeds its rate of removal. This level of intensity also happens to coincide with muscle fatigue. Gross mechanical efficiency refers the relationship between power output and the energy required to produce it.

Of these three variables, gross mechanical efficiency may provide you with the most room for improvement. As for the other two variables, maximal aerobic capacity can take up to five years of consistent training to develop, while lactate threshold is very responsive to training among novices but eventually plateaus in highly trained athletes.

Gross mechanical efficiency relates to the precision with which an athlete in any sport is able to move their limbs, and while improvements may be limitless, they also require many dedicated hours of perfect practice. The more efficient your movement patterns are, the less energy is required for the activity – a prime consideration in endurance sports.

However, while it’s easy to see how improvements can be made in an athlete’s swimming or running technique, it’s not so easy when it comes to cycling. After all, once your feet are clipped into the pedals, their movement pattern is largely prescribed by the machinery. And yet researchers from the University of Kent have recently shown that just two high-intensity interval training sessions per week can boost cycling efficiency by 1.6 per cent.

Time savings

Efficiency simply explains how much power (work) an athlete can generate for a given level of oxygen consumption (energy). The range of efficiency in endurance-trained cyclists has been shown to be between 18 per cent and 23 per cent. To highlight just how important efficiency is to your performance, let’s compare two imaginary cyclists. Cyclist A and cyclist B are identical in every aspect other than their efficiency. Over a flat, windless 40km time trial, we know that cyclist A (who has an 18 per cent efficiency rating) produces an average power output of 230w, which translates into an average speed of 38.8km/h. His finishing time is 1:01:46. Cyclist B has an efficiency rating of 23 per cent and, under exactly the same conditions, is able to produce an average power output of 293w for the 40km time trial. This equates to an average speed of 42.6km/h and a finishing time of 56:15. This means approximately 12w are gained for every one per cent increase in efficiency in this example.

This example uses two extremes of cycling efficiency, but the reality is that almost all cyclists fall within a much tighter range. In a famous study conducted by the University of Texas on Lance Armstrong over the period from 1992 to 1999, researchers found that the seven-time Tour de France winner improved his efficiency by 1.9 per cent. The researchers suggested that this might have come about as a consequence of the sheer volume of cycling Armstrong undertook during that period. It should be noted though that efficiency gains are much harder to come by in a highly trained elite athlete, while the potential benefits may be considerably greater for amateur athletes.

How to improve

So how do you go about becoming more efficient on a bike? In a study published by the Simon Fraser University in British Columbia, researchers concluded that cycling in the relatively low intensity range of 55-60 per cent of VO2 max (approx 70-75 per cent of max heart rate) is an effective way to improve leg-muscle coordination patterns and thus cycling efficiency. It isn’t that surprising that professional cyclists clock up over 30,000km per year, the bulk of which is conducted at this relatively low intensity. However, long, slow rides are not the only way to improve efficiency. Dr James Hopker and his team at the University of Kent have recently shown that a six-week phase of specific training sessions involving a combination of maximal aerobic and sprint intervals was sufficient to improve efficiency in a group of moderately trained cyclists, by 1.6 per cent. Having already established just how sensitive performance is to relatively small changes in efficiency, this is an improvement that we should all be striving for.

Pedal technique

It is worth pointing out at this stage that artificially altering your pedalling technique (by trying to pedal in circles, pulling up with your toe down and pushing with your heel down) is more likely to reduce your efficiency than improve it.

Exactly what is going on in the body when we become more efficient is still mostly unknown. Current thinking is that a combination of adaptations occurs in the powerhouses of the muscles (mitochondria), in oxygen delivery and extraction, in aerobic enzyme concentrations and even in changes to the respiratory muscles that result in a lower energy cost for breathing.

The exact mechanism for the improvement in efficiency that can be derived from specific training still has the scientists scratching their heads. But don’t let that stop you. Commit
to six weeks of quality cycling workouts and your next 40km bike leg is also likely to be your next PB.


Improve your cycling efficiency in six weeks with this scientifically proven training advice

Week 1 and 2

  • Session 1 – 2-5hrs at 70-75% of max heart rate
  • Session 2 – 6x10sec maximal sprint intervals with 4min recoveries
  • Session 3 – 3x4mins at evenly paced maximal effort with 4min recoveries

Week 3 and 4

  • Session 1 – 2-5hrs at 70-75% of max heart rate
  • Session 2 – 8x10sec maximal sprint intervals with 4min recoveries
  • Session 3 – 4x4mins at evenly paced maximal effort with 4min recoveries

Week 5 and 6

  • Session 1 – 2-5hrs at 70-75% of max heart rate
  • Session 2 – 10x10sec maximal sprint intervals with 4min recoveries
  • Session 3 – 5x4mins at evenly paced maximal effort with 4min recoveries

This article was originally published in Triathlon Plus magazine. Save time and money by having every issue delivered to your door or digital device by subscribing to the print edition or buying digitally through Zinio or Apple Newsstand.

You’ll find loads more triathlon training advice in’s Training Advice section.

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