Cyclists: sit back to get ahead

As I sit here writing this, the riders in this year’s 2018 Tour de France will be literally battling through the hardest stage of the whole race. With over 5,000m (16,500ft) of altitude gain facing them, it’s going to be absolutely savage. The Col de la Madeleine takes no less than two hours to climb. It goes up forever, then there’s a flat bit in the middle, after which it just seems to go on forever again. And that’s just the first climb. After a brief high-speed descent, there are a further two Alpine climbs to contend with, finishing at the summit of Alpe D’Huez.

How do they do that?

For many amateur riders, even completing this stage would be a real challenge. To race it however requires not only extraordinary ability, but preparation and attention to detail too. Unsurprisingly, this means that factors such as the riders’ nutrition, training and bike technology are constantly placed under the microscope. And with no stone left unturned by the Tour teams, you can bet that among these factors is rider position.

As any cyclist knows, setting up the bike correctly is vital for efficient (and pain-free) riding. Among the things to consider are the saddle height, saddle tilt, saddle fore/aft position, the stem/handlebar height and stem length. And of course assumes that the size geometry of your frame is reasonably matched to your body dimensions in the first place. Of all these aspects, saddle height is the simplest and least troublesome adjustment to make – just flick the quick release lever, adjust and retighten. But a recent study has suggested that optimising saddle ‘setback’ (how far forwards/backwards the saddle sits on the seatpost – see figure 1) can also have a much greater impact on pedalling efficiency than was hitherto thought [Sports Biomech. 2016 Nov;15(4):462-72].

Figure 1: Saddle setback

In this study, scientists set out to investigate the influence of saddle setback on pedalling effectiveness by looking at how efficiently the cyclists were able to generate force through the pedals, and how efficient they were at sustaining a constant workload. Eleven cyclists were assessed in six saddle setback positions while pedalling at a steady power output of 200 watts at a cadence of 90 rpm. A force sensor was integrated within the seat post to compute the centre of pressure on the saddle, and pedals with force sensors were used to calculate how efficiently the force applied to the pedal was converted into crank force (ie the force needed to drive the bike forwards). By analysing motion and force throughout the pedalling motion, the researchers were also able to calculate which position resulted in the most efficient steady-state cycling.

In comparison with a more forward setback position, sitting backward significantly decreased (by 5%) the cumulative total work performed by the cyclists. This fits with previous research showing that sitting further forward favours maximal power output – useful for sprint cyclists, and almost certainly the kind of position that cyclists on the track are using. However, in terms of force and steady-state pedalling efficiency, sitting further back resulted in gains of around 2% – ie less muscular energy was required from the cyclists to maintain a 200 watt output.

Implications for amateur cyclists

What does this research mean in plain English? Well firstly, it shows that the amount of setback has a significant influence on your pedalling efficiency so it’s worth paying attention to. Secondly, while a more forward position might allow for higher force generation, it’s not so efficient for maximising pedalling efficiency at lower, sustained workloads. A 2% gain in efficiency with more saddle setback might not sound a lot, but over the course of a long ride such as a sportive or long time trial, it could make a noticeable difference, and result in less fatigue.

Rider position on the bike not only affects efficiency and power generation, it also has a big impact on aerodynamics. These are topics we have covered in depth in Peak Performance, and all the evidence suggests that attention to detail really does help – not just Olympic champions, but amateurs and recreational cyclists alike. To read more and understand how you can boost your cycling performance, just click on the links below. After all, what cyclist doesn’t want to go further or faster for less effort?!

Andrew Hamilton, Peak Performance editor

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