Powerfile analysis of Bas Diederen IM Maastricht 2015

Race: Ironman Maastricht 2nd August 2015

Athlete: Bas Diederen, pro-triathlete (Team4Talent)

Powermeter: Quarq Elsa

Bike: Canyon Speedmax

  • Bas Diederen is one of the top pro-triathletes in the world. In 2011 he was the top amateur triathlete at the Ironman World Championships after finishing 26th overall in a time of 8:48:44. Recently he won Ironman Maastricht and we were fortunate to get his power file from the race for analysis.

When we take a look at Bas’s power file we see that he averaged 282 watts during the race. His normalized power was 317 watts with an intensity factor of .81. Simply put this means that Bas’s effort felt like he was riding at 81% of his Functional Threshold Power (FTP). This is because intensity factor is the ratio between normalized power and a persons’ FTP. With a total of about 1000 meters of climbing and an average speed of 39 km/h, Bas did 4773 kJ of work, which resulted in a TSS of 310.

Bas1 totaal




Bas had a great swim; finishing in 46min and 22sec. Coming out of the water Bas was in the lead group of 5 athletes. Once on the bike there was no time to relax as he pushed a normalized power of 332 watts for the first hour of the race. This high pace helped to further separated the lead group of 5 riders from the chase group.

Bas2 1e uur


50km into the bike Bas lost the ability to shift his electronic gears and was forced to continue racing in a 55×13. Heading up the climb of the Cauberg, Bas was really struggling to not overextend him self with such a low cadence and high effort. However, with some smart pacing he was able to stay with the other riders in the lead group.

Bas5 Cauberg 1 Bas6 Cauberg 2



Heading into the second lap Bas attacked to create a lead before climbing the Cauberg a 2nd time. After 134 km he pushed his best 10min peak power of 390 watt NP to gain a 5 min lead over the chase group, which he was able to sustain all the way to T2.

Bas3 aanval Bas4 aanval lokatie


With a marathon time of 2 hours, 51 minutes and 59 seconds Bas demonstrated that he had done a great job pacing himself throughout the race. It was this great pacing strategy which propelled Bas to his first professional Ironman race win, in a time of 8:27:18.



Guido Vroemen

Sportsmedicine and exercise physiologist, trainer, powermeter expert