Power Analysis: Zirbel, Kreuziger perfect the time test

Hunter Allen analyzes the power data from Tom Zirbel and Roman Kreuziger in the final-stage time trial at the USA Pro Challenge

Editor’s Note: Hunter Allen, one of the sport’s foremost experts in training with power, is the author of ”Training and Racing with a Power Meter”, the co-founder of TrainingPeaks WKO+ software and the founder of Peaks Coaching Group. Allen will join us throughout the USA Pro Challenge to look at the power numbers the sport’s top riders are laying down in Colorado.

Stage 7 Denver Individual Time Trial (9.5 miles)

View this stage in the full TrainingPeaks activity viewer for Tom Zirbel and Roman Kreuziger.

Stage Results
1 Taylor Phinney, BMC Racing in 0:17:25
2 Christian Vande Velde, Garmin-Sharp at 0:00:13
3 Tejay van Garderen, BMC Racing at 0:00:19
6 Tom Zirbel, Optum-Kelly Benefit Strategies at 0:00:31
47 Roman Kreuziger, Astana at 0:01:32

Tom Zirbel (Optum-Kelly Benefit Strategies) gave the big guns a run for their money in the final stage of the USA Pro Challenge, the individual time trial in Denver. An incredible time trialist, Zirbel has for years been one of the best in the U.S. and didn’t disappoint on Sunday. He finished in sixth place, really giving his all for a top placing, averaging 448W and 31.7 mph.

Have a look at the screenshot from Zirbel’s ride today. He paced this time trial perfectly. He nailed the start by holding himself back in the first three minutes and then he settled into his pace, right at 450-465W. Zirbel held this all the way to the end of the time trial and pushed himself in the last three minutes at 471W. Now, Zirbel is admittedly a big boy at 175 pounds (79.5kg), and thus may be expected to put out bigger wattage numbers. But a 448W average divided by 79.5 kg is still 5.63 w/kg — a seriously big number at elevation.

The power files from professional time trials, when done right, are pretty boring. Zirbel’s shows us how he rode right on the edge of his functional threshold power of 450W for the entire effort and absolutely made this a boring file, in a great way. Nothing to critique — he couldn’t have gone any faster in one section or another. He rode a perfect time trial. Congratulations Tom!

Roman Kreuziger (Astana) finished 1:32 behind winner Taylor Phinney (BMC Racing), and rode a very respectable time trial. Contrasted with Zirbel, Kreuziger is much smaller at 147 pounds (67kg), so his power output of 326W may initially seem like a massive difference from Zirbel’s 448W. However, the watts-per-kilogram ratios are much closer; Kreuziger’s was 4.9 w/kg — a level below Zirbel’s ability to time trial, but still highly respectable. Kreuziger is a long-time professional and knows how to pace himself. He didn’t start too hard, he held to his threshold power for the entire time trial, and he pushed his pace in the final three minutes just like Zirbel, showing that he could finish strong.

Both riders rode at their maximum, and both are consummate professionals. The only difference in their placing and times? Their functional threshold power. Zirbel’s FTP was higher than Kreuziger’s, and that’s the difference.

These guys are just incredible — it’s hard to put in words and unless you analyze the data, it can sometimes escape you. There is no other sport that I know where each of us on a daily basis has the opportunity to compare ourselves against the world’s best, using a power meter. How would you have done in the time trial? Would you have been able to finish in the top 100? The top 50? And remember, these guys have been riding hard for a week now.

The ability to crack out those watts and push yourself to the limit is something that each of us strives to do; it’s part of why we race and why we ride. Ultimately, there is nothing like the time trial — the test of truth — to find out what we’re made of.

Editor’s Note: For more USA Pro Challenge race files and analysis visit