Power, precision and the art of time trialling

By Dr Ryan Worn

On paper, the road cycling time trial is a simple event to win. It requires the combination of high sustained power, an aerodynamic position and the ability to tolerate pain. It is a specialised event that favours those athletes with the right mix of abilities. So what are those abilities and how do they enhance performance?

There is no guaranteed template for TT success. There have been powerhouses like Fabian Cancellara and Bradley Wiggins who can hold close to 500 watts of power for 30 minutes. Then there are the aerodynamically privileged like David Zabriskie and David Millar who are able to hold low positions that minimise wind resistance for long periods.

Yet it is not enough to be just powerful or just aerodynamic. The best TT cyclists are often some of the best General Classification riders and brilliant climbers. So what is it that makes them elite?

Physiologically speaking, the best climbers and best TT riders aren’t that different. According to research by Alejandro Lucia, a professor in sport and physical activity at the University of Madrid, both types of riders have very high absolute VO2 max scores (a measure of one’s ability to use oxygen) of around five litres per minute and both are able to hold high relative power outputs at their threshold of around six watts per kilogram.

“Perhaps what is most critical for success in TT cycling is the speed and power which cyclists can sustain for 45-60 minutes,” suggests Dr Bradley Clark, a specialist in exercise physiology from the University of Canberra.

“Physiologically, the ability to hold that pace is largely determined by an athlete's lactate threshold and their VO2 Max.”

According to the research by Professor Lucia, what separates TT cyclists from climbers is that TT specialists are able to produce greater total power outputs (irrespective of body weight) and tend to pedal with improved technique. These differences may also explain what makes GC riders so special – they are able to produce high powers, both absolute and relative to their body weight and also have excellent pedalling technique.

The pedalling technique element is an interesting one and is a growing area of cycling research. What the research tells us is that during events like the TT, as cyclists become fatigued, they tend to have a reduction in pedalling technique and produce counterproductive force during the pedalling upstroke.

The worse performing TT cyclists tend to have poorer pedalling technique, lower aerobic capacities and rely on their dominant limb for power production more than their high-performing counterparts.

When cyclists become fatigued, in order to maintain power they often increase the activation of their quadriceps muscles and try to extend further through their hips as a way of increasing downstroke force.  However, this strategy is costly and may contribute to an increased need for oxygen to fuel the working muscles and might lead to early fatigue.

That is, better TT cyclists seem to be able to maintain pedalling technique for longer (perhaps through improved pacing) and seem to be better at slowing fatigue in the upstroke (hip, knee and ankle flexor) muscles.

While pedalling technique and an athlete's physiology are key factors, what is most important is the aerodynamic profile of the athlete, according to Dr Rodrigo Bini, a cycling biomechanist and Lecturer at La Trobe University.

“Time trial cyclists have to sustain the largest possible power to cover a predetermined distance. Given drag is the largest opposing force affecting cyclists riding solo, it is critical that time trial cyclists minimise drag in order to reduce power output and energy cost at high speeds,” Dr Bini said.

“Reducing frontal projected area and improving ‘aerodynamic shape’ seems to be the most effective way to reduce drag. However, aggressive aerodynamic positions may impact cyclists in terms of comfort and muscle force contributions to power output. At this stage though, there is no published research determining the trade-off between reductions in drag and increases in energy cost when opting for increased upper body forward flexion.”

Perfecting the time trial is difficult and requires practice to minimise fatigue and maximise speed.  A large part of the strategy to improve racing performance comes from monitoring an athlete’s power. Gone are the days of a TT cyclist riding by feel. For the best riders, it is now all metred, dosed and modelled. Dr Ryan Worn

Most of the best time trial riders are following an intensity set by their power meter and that optimal power is determined through testing and training. Typically, better riders are holding power outputs around 75-80 per cent of their maximum obtained during an incremental test. This power typically occurs slightly above the athlete's lactate threshold and cannot be sustained for long periods.

Recent research indicates that this power fluctuates according to terrain and cadence, but the best athletes seem to maintain relatively consistent pacing strategies that involve a harder start, followed by consistent pacing before an all-out effort closer to the finish.

It is important to remember that although the TT can be planned meticulously, it often goes wrong. Think Bjarne Riis throwing his bike in the 1997 Tour De France or Michael Rasmussen’s two crashes and four bike changes during the 2007 tour.

Crashes and mechanical faults aside, it is common to see athletes not perform to expectation, such as Laurent Fignon losing 58 seconds to Greg Lemond during the 1989 Tour De France TT and famously losing the overall victory by 8 seconds, or Cadel Evans failing to make up time on Carlos Sastre, a known weak TT rider who went on to win the 2008 Tour De France.

If these events demonstrate anything, it is that perhaps for an event so precise, there is more room for things to go wrong. If perfection is the ultimate aim, then perhaps it is relatively easier to fall short. In light of this, it makes sense that if a rider wants to perform well at the TT, they need to test meticulously and practice on their race equipment under a variety of conditions over and over.

As Bob Larsen, the famous American running coach said: “plan the race and race the plan.”

This article was first published in November 2019.

Dr Ryan Worn is a Lecturer in Exercise and Sport Science in the Institute of Health and Wellbeing and a former elite cyclist. The 2023 Federation University Road National Championships will be held in Ballarat and Buninyong from January 6-10 2023.