The Myth of the Bike Leg

There’s a commonly held belief that, as a triathlete, you should focus your training on the bike if you want to achieve the fastest possible time. At the end of the day, the bike does form the longest leg of any triathlon, so surely the notion of ‘bike first’ makes sense. Of course, not every piece of conventional wisdom is true, take the Earth being flat or that eggs are bad for you. This week, we lift the lid on the issue and get to grips with where you should focus your training efforts.

To help us explore this issue, we’ve analysed the results of the 2018 Ellesmere Standard Distance Triathlon, a super popular event, which previously had been one of the ITU Age Group qualifying events. In 2018, there were 272 finishers with a winning time of 01:51:48 and a lantern rouge of 03:45:21, which gives a time difference of 01:53:33 meaning that the last place finisher completed the course in approximately double the time of the overall winner, a pretty normal outcome in triathlon.

When we delve a little deeper, the splits provide some interesting insights:

LegFastestSlowest
Swim 00:17:09 00:45:39
T100:00:3800:05:27
Bike00:57:0701:33:00
T200:00:1400:03:08
Run00:35:0001:46:07
Overall 01:51:4803:45:21

The first thing that jumps out is that the slowest bike leg is roughly fifty per cent slower than the fastest. Yet, the slowest swim and run are almost three times as slow as the fastest. On the face of it, this suggests that the bike is the most levelling of all the legs, which, in turn, leads us to think that gains on the bike will result in the lowest relative gains overall. 

The second point of interest comes about when we look at the fastest and slowest finishers and see if they featured in the fastest or slowest splits. What we find is that the overall winner was a minute and a half behind the pace in the water, but posted the fastest splits for T1, the bike, and the run. At the other end of the field, the slowest finisher posted mid-field bike and T2 splits, a slow swim (270th of 272) and the slowest run. 

Comparing the slowest and fastest competitors doesn’t really shed any light on the importance of the bike, in fact, it doesn’t provide any answers with regard to any of the disciplines, other than fast people are fast and slow people are, generally, slow.

To make our exploration more informative, we’ll ignore the top ten per cent and bottom ten per cent of finishers. This will give us a more realistic view of competitors’ times. It makes sense to disregard the slowest ten per cent because this contains plenty of people struggling with an injury, taking part in their first event with little training, and those that have hit the wall for whatever reason. Likewise, the top competitors can skew our findings because an event may attract exceptional talent or a larger number of elite athletes because of its geographic location or position in the triathlon calendar relative to key races, such as ITU qualifiers or GB Championship events.

There are another couple of things that are useful when we ignore the extremes of finishers. In many cases, placing close to the top ten per cent will give you age-group points or qualification. Also, you can see exactly what you need to achieve to move from bringing up the rear of the field through to possibly gaining a top ten place in your age group. So, here are the splits:

Leg1st Decile9th DecileDifference
Swim00:20:5700:30:4300:09:46
T100:00:5500:02:3000:01:35
Bike01:03:1001:22:2700:19:17
T200:00:3900:01:2500:01:46
Run00:40:1100:58:5000:18:39
Overall02:08:0302:52:4900:44:46

Now, we get a very different picture and one that’s a lot more useful to us. We’ve all heard it before, but the evidence highlights, transitions, the fourth discipline, are worth practising. There are a whopping 3 minutes and 21 seconds to be gained, and most of that is through practice and good technique. Think of it is as time for nothing. 

The swim difference of 9 minutes and 46 seconds represents a fifth of the overall time difference, making it the smallest gain of the three main disciplines. The irony here is that many people invest a lot of their time in swim practice as if it’s some kind of holy grail of triathlon when in reality hard earned seconds gained in the pool could be replaced with simple transition practice and preparation.

The biggest time differences and potential savings are offered by the bike and run legs, with the bike narrowly pipping the run to the post, although, I suspect, an analysis of other events may prove that they are even more closely matched. So, what does this mean? Certainly, it blows the lid off the idea that our greatest time savings are to be made solely on the bike - the run is equally important. Also, if we consider that aero equipment and bike positioning will have influenced bike times and that training for the bike is the biggest drain on our precious time, perhaps we should focus our attention on the run to maximise our time gains. 

Surprisingly, the actual results of real triathletes in a real event demonstrate that focusing on the bike to maximise time savings is a myth, nebulous at best. Considering the data, if you want to achieve a PB in your next event, you should:

  • Train for all disciplines so that you don’t end up in that bottom ten per cent, and you gain the aerobic benefits of swim training

  • Don’t make swimming the ‘be all and end all’ - it offers hard-earned marginal gains

  • Practice and perfect transitions - they’re time for nothing

  • Invest in a bike fit and spend ludicrously on the best gear - time saved with no training required

  • Balance out your run and bike training, perhaps getting a coach to improve your run speed

I hope you enjoyed this week’s post, and it’s given you something to mull over. Remember, whatever you choose to do, enjoy it - that’s what it’s all about. So, until the next time, happy training.

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