Power Analysis: The incredible numbers set by the leading men at Unbound Gravel

Diving into the data numbers from Keegan Swenson, Peter Stetina, and Laurens ten Dam.

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In this column, we look at the power numbers of Keegan Swenson, Peter Stetina, Laurens ten Dam, and others at Unbound Gravel.

Raindrops fell from the sky in the days preceding Unbound Gravel, turning hundreds of miles of Kansas gravel into a mixture of mud, rocks, roots, and packed dirt. The conditions were vastly different from previous years which took place under the beating sun, where heat and humidity had been the downfall of riders’ past, along with countless crashes and mechanicals, as well as epic bonks.

This year’s Unbound Gravel was faster than ever – now a part of the Lifetime Grand Prix – as professional riders flocked from around the globe to test the gravel roads around Emporia, Kansas. There were Dutch men and women, Italians, Canadians, Australians, New Zealanders – and of course, your favorite American riders such as Alexey Vermeulen, Ian Boswell, Peter Stetina, and Payson McElveen.

A story on the women’s power data is in the works.

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The rain wasn’t constant, but it did fall in the lead up to the race, which meant the packed gravel roads would be slick and fast. But when the heavens opened up in the middle of Unbound Gravel, the conditions changed, the wind shifted, and dirt became mud, leading to crashes and a changing of the guard. Mountain bikers then had a distinct advantage, one that had been enjoyed by the roadies during the fast start.

But that didn’t stop professional mountain biker Keegan Swenson from making it into an early breakaway including current and former pro road riders Logan Owen, Freddy Ovett, Thomas Dekker, and Alexey Vermeulen.

Swenson – Early attacks from Mile 9 to 63
Time: 2:40:08
Average Power: 277w (4.2w/kg)
Normalized Power: 316w (4.8w/kg)

Inside the first 100 miles, the attacks kept coming, even with over half the race remaining. Former WorldTour pro, Laurens ten Dam, put on a show at Unbound Gravel, attacking with over 200km to go and building up a multi-minute lead. The Dutchman was arguably the strongest rider of the day, but he would pay for his early efforts.

Ten Dam – Long attack from Mile 78 to 135
Time: 2:32:33
Average Power: 328w (4.8w/kg)
Normalized Power: 342w (5w/kg)

Ten Dam was on a three-minute yo-yo with the Unbound peloton, first going up the road with a three-minute lead, but then getting caught, dropped, and left three minutes behind the lead group. Somehow (i.e. with a lot of power), Ten Dam made it back, even throwing in some late attacks amongst the lead group.

Two-thirds of the way through the 200-mile race, that front peloton was composed of defending Unbound Ian Boswell, Peter Stetina, Ivar Slik, Alexey Vermeulen, and Keegan Swenson. The leading five powered past ten Dam in the hills, but the Dutchman fought back with a valiant effort.

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I’ve included a full breakdown of Keegan Swenson’s Unbound Gravel, hour-by-hour, at the end of this article. This middle section was the hardest of the race, with Swenson routinely pushing 400-500w on the uphills, and holding 250-350w on the flats. Hour 5 and Hour 7 were the hardest, with Swenson’s normalized power being well over 300w.

Looking at ten Dam’s ride, it was closer to a nine-hour time trial than a 200-mile gravel race. We can see from his power file that there were very few spikes, and a normalized power within 10-20w of the average power. There were even long, 30-minute sections of ten Dam doing 330-350w without coasting – an impossible feat for anyone caught in the scrum of the Unbound peloton.

Ten Dam – Chasing back onto the front group
Time: 2:30:41
Average Power: 287w (4.2w/kg)
Normalized Power: 307w (4.5w/kg)
Final push to catch back on: 332w (4.8w/kg) for 36 minutes

Peter Stetina was part of the lead group until roughly Mile 164, where Slik, Swenson, and Boswell broke off the front of the lead group. Vermeulen and ten Dam would eventually make it back, whereas Stetina would not – after the race, he would say that he completely cooked by Mile 164, and that he wasn’t recognizing people at the final aid station.

Stetina – What it looks like when you bonk at Unbound Gravel
Time: 4:58:15
Average Power: 236w (3.8w/kg)
Normalized Power: 257w (4.1w/kg)
Normalized Power before bonking at Mile 164: 273w for three hours
Normalized Power after bonking at Mile 164: 221w for two hours

The leading group of five worked together on the hard-packed roads to Emporia, and with a few miles to go, it looked like it would be coming down to a sprint. But that didn’t stop multiple attacks in the final kilometers, as we can see from the sharp spikes in Swenson’s power file. After over nine hours of racing, Swenson broke 1,000w four times in the final 1,500m, but that wasn’t enough to overhaul Ivar Slik, who sprinted to the win at Unbound Gravel.

Swenson – Final 1.5km
Time: 2:59
Average Power: 402w (6.1w/kg)
Final Sprint: 868w (13.2w/kg) for 20 seconds
Peak 5-second Power: 990w (15.1w/kg)
Max Power: 1163w (17.6w/kg)

There once was a time when Unbound Gravel was more of an ultra-endurance test than a 200-mile gravel race. In the past, the lead group would slowly dwindle as riders bonked, flatted, crashed, or baked to completion in the Kansas sun. But now, the level is so high that these riders are full-on racing for 200 miles. Their power hardly drops from hour 1 to hour 9, and the attacks are arguably sharper at the end.

The lead group has gotten bigger each and every year, as two or three or even five riders refuse to be dropped. When it all comes down to a final sprint, after nine and a half hours at nearly 300w, the finishing kicks are faster than ever.

In this year’s edition, this is what it took for Keegan Swenson to make the front group at Unbound Gravel, and sprint to second place behind Ivan Slik.

Hour 1: Average Power: 264w (4w/kg) Normalized Power: 299w
Hour 2: Average Power: 262w (4w/kg) Normalized Power: 299w
Hour 3: Average Power: 287w (4.4w/kg) Normalized Power: 331w
Hour 4: Average Power: 263w (4w/kg) Normalized Power: 290w
Hour 5: Average Power: 301w (4.6w/kg) Normalized Power: 326w
Hour 6: Average Power: 280w (4.3w/kg) Normalized Power: 294w
Hour 7: Average Power: 291w (4.4w/kg) Normalized Power: 318w
Hour 8: Average Power: 268w (4.1w/kg) Normalized Power: 288w
Hour 9 (and 24 minutes): Average Power: 248w (3.8w/kg) Normalized Power: 281w


Swenson – “Unbound 200. What a day…. 2nd in the 5 up sprint.”
Kilometers: 321
Time: 9:21:26
Average Power: 272w (4.1w/kg)
Normalized Power: 303w (4.6w/kg)
Max Power: 1163w (17.6w/kg)
Energy Burned: 9179kJs
Elevation Gain: 2408m (7900ft.)


Power Analysis data courtesy of Strava

Strava sauce extension


Ian Boswell
Laurens Ten Dam
Peter Stetina
Keegan Swenson

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