Sprint analysis from Herald Sun Tour Stage 3 – the importance of timing
24 February 2016
When it comes to sprinting the talk is always about how many watts the rider produces at max or the riders peak 10 second average. While being able to produce a high peak power over a short explosive effort is incredibly important, the art of sprinting has so many more factors. In this short analysis from stage 4 of the recent Herald Sun Tour we will look to break down in detail the final 16 seconds of the stage from 3 riders who finished inside the top 10 and show how timing, aerodynamics and positioning are such crucial components of standing on the podium at the end of a race.
By using the Ride graph in Today’s Plan we are able to isolate the 3 sprinters last 16 seconds of the race and delve into the peak power (watts), cadence (RPM) and speed (km/h) and see exactly what it takes to finish in the top 10 of the Herald Sun Tour and also what intricate details occur in sprint finishes that are not just about pure horse power.
In this first graph we are looking at the 3 riders power output in watts, this is shown in 1 second intervals with no smoothing applied. The annotations on the graph tell the story of the power and what and how it was applied for each rider.
The next graph looks at how cadence was applied by the 3 riders. You can see that the trace and cadence of the lead out rider (rider 2) and the highest placed finisher (rider 1) are very similar. Rider 3 changes gear twice in the final dash for the line and does so just before the biggest power spike in the data. This unfortunately coincides with the lead out rider making the last little effort and increasing speed. This meant that the sprinter went to come round the lead out man just as he did a final acceleration and along with the gear change he hit the wind with little momentum and effectively stopped accelerating.
In the next graph we look into the 3 riders speed over the finish of the race. when compared to the power above it is clear to see that simply producing more watts does not correlate to going faster. Positioning and being on the correct wheel, maintaining a draft and popping out late for the final charge can be vitally important to increasing speed and finishing position.
In the next series of graphs we have now shown the 3 riders power, speed and cadence data individually to understand how it all related to each other for the individual athlete.
The first combined graph looks at rider 1 the highest placed finisher on the stage. It is very interesting to note that the power for rider 1 was quite consistent, but, not even close to his PB numbers. Speed continually rises, this alludes to great aerodynamics and positioning meaning he didn’t need massive power because he followed the right wheels and was always in disturbed air.
In the next graph we look at the combined data from rider 2 the lead out man. It is clear that the lead out guy has done his job here and positioned his sprinter right near the front of the bike race in the difficult finishing sprint. His small acceleration with 250-300 metres to go may just have occured at the wrong time for his sprinter who stepped out to start his sprint into the wind and basically stopped accelerating. Rider 2 basically stopped with 200 metres to go, but, actually rolled across the line before his sprinter. This was due to being in disturbed air as others came around him and carrying his momentum and speed to the finish.
The final graph we look at rider 3 the sprinter and his combined data from the sprint. There are so many variables that need to come together to win a bunch sprint and on this day the stars didn’t align. There are some interesting data points in this graph that could explain a few things and also help for future sprint planning. You can see that early on in the sprint as rider 3 came around the final right hander that he accelerated by spinning up the gear to 126 RPM. This would have been to get right onto the wheel of his lead out man. As he accelerated and then changed gear (this can be see by the noticeable drop in (cadence) he would have come up onto the back wheel of rider 2. If he had been able to carry this momentum on and come around the lead out man at that point he may have continued to accelerate faster towards the finish, however, at this moment the lead out man also did his final acceleration and this may have occurred at just the wrong time meaning he stepped out to sprint and into the wind a little early.
In the final chart we look at rider 1 and his decay in power over the length of the sprint and compare it to previous data on record. This can be used to understand the nature of the type of sprinter and also to determine lead out position. The guys with the most power decay, but the biggest power would be the final sprinter. Those riders with the least power decay and ability to sustain high power over a longer period might be the final lead out men who take it on with 1 km to go or for the final 500 m of the race to deliver the sprinter right to the final 250 metres.
The intricacies of getting the sprint finish of a race exactly right is an art form. Trying to understand it in the data and fine tuning the process in the future is what enables us to get better and better at the process. With sprint finishes being won at 70+ km/h there is not a lot of time to actually think about these processes, so learning them, repeating them in training is what is needed to get it right come race day.