Power analysis: LeadBoat Challenge

We dive into the power numbers of Keegan Swenson, Peter Stetina, and Ian Boswell from the 2021 Leadville - SBT GRVL double.

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The inaugural LeadBoat Challenge — the Leadville 100 and Steamboat Gravel (SBT GRVL) — took place this past weekend, and the two-day, 400km combined distance race crowned its first men’s and women’s winners. Keegan Swenson dominated the Leadville 100 on Saturday, beating Lachlan Morton by nearly eight minutes. But on Sunday, the (former) road stage racers got their revenge as Alex Howes took the win versus Ian Boswell and Peter Stetina in a three-up sprint.

In this column, we’ll look at power numbers from both races, and see how each race was decided due to a combination of high altitude, quick decision-making, and pure strength.

I don’t write mountain bike articles very often – this might be my first-ever mountain bike power analysis – but the Leadville 100 is worthy of a close examination. If you watched any of the Olympic mountain bike races, you might be expecting a 1-2 hours race, with some steep climbs and rocky descents. But the Leadville 100 is a completely different beast.

The 2021 Leadville 100 was 105mi (169km) long with 11,800ft (3,600m) of climbing. If the route profile weren’t hard enough, the altitude that truly made one hurt. Starting at nearly 10,000ft (3,000m) elevation, the Leadville course climbed all the way up to 12,500ft (3,810m) at the top of Columbine, which came about halfway through the race. The 73km lead-in to Columbine was anything but easy – even with the front group still all together, Swenson held over 4w/kg normalized power for two and a half hours.

Keegan Swenson's power before Columbine
Keegan Swenson’s power data from before the Columbine ascent.

On each climb, Swenson was pushing 300-400w (4.5-6.1w/kg), and then coasting down the descents. But when it came to technical skills, mountain biking demands a lot more than road racing. Riders were traversing dirt and gravel trails that were covered in rocks, ruts, and roots. Their suspension absorbs some of the impact, but their upper body does a whole lot more work that Pogačar’s does while coasting down Mont Ventoux.

Almost halfway through the race, Swenson and the front group hit the Columbine climb that was 10.3km at an average of 8.9 percent. There were long, steep ramps of over 13 percent, and the road wasn’t paved. Near the top, there was a straight section of 13 percent where Swenson was pushing over 5w/kg and not even going 6mph (9.7kph).

Keegan Swenson's power data from the Columbine ascent.
Keegan Swenson’s power data from the Columbine ascent.

Swenson – Columbine:
Time: 49:22
Average Power: 308w (4.7w/kg)
First 1.8km (avg 8.3 percent): 331w (5w/kg) for 7:45
Last 1.8km (avg 11.8 percent): 290w (4.4w/kg) for 12:07

Don’t let these numbers fool you – Keegan Swenson is just as strong as — if not stronger than — professional road riders. The insane altitude (over 10,000ft) took a huge toll on athletes’ performance, especially multi-hour endurance events. Most people had to walk at the top of Columbine, but Swenson was still able to keep the pedals turning at over 4w/kg.

The lead group – Swenson, Morton, and Olympian Howard Grotts – came down Columbine together and continued on towards the final crux of the course, Powerline. Lasting 6km at an average of 7.6 percent, Powerline wasn’t as hard as Columbine, right? Well, the climb has a handful of downhill portions, and has multiple sections over 20 percent.

Swenson made his winning move on Powerline, and pushed nearly 6w/kg up the trail which climbs from 9500ft to 11,000ft.

Swenson – Powerline:
Time: 26:39
Average Power: 314w (4.8w/kg)
Normalized Power: 324w (5w/kg)
First Kilometer (avg 14.2 percent): 347w (5.3w/kg) for 6:25

After descending Powerline, Swenson was in TT-mode, pedaling like a metronome, and ripped down the descents as fast as he could. On the road and trails to the finish, he was still able to push 320-350w (4.9-5.3w/kg) on the bike, and put minutes into his chasers.

By the top of Powerline, Swenson was already five hours into the race, had burned more than 4,500kJs, and earned 300 TSS. Most of us have never done a ride that hard and that long; but Swenson was hardly slowing down.

Keegan Swenson's power data from Powerline to the finish
Keegan Swenson’s power data from Powerline to the finish.

Swenson – Powerline to finish:
Time: 1:02:27
Average Power: 249w (3.8w/kg)
Normalized Power: 282w (4.3w/kg)
Turquoise Lake Climb (avg 4 percent): 322w (4.9w/kg) for 12:03

Swenson’s steady state power dropped by 10-20w in the final 20km; but then again, he had an eight-minute lead. In the end, Keegan Swenson absolutely dominated the Leadville 100 with a power file that looks straight out of the WorldTour.

Keegan Swenson's power data Leadville 100 mountain bike race
Keegan Swenson’s power data Leadville 100 mountain bike race.

Swenson – Leadville 100:
Kilometers: 169.4
Time: 6:11:54
Average Power: 250w (3.8w/kg)
Normalized Power: 285w (4.3w/kg)
Energy Burned: 5587kJs
Elevation Gain: 3,654m (11,988ft.)

Less than 18 hours after finishing the Leadville 100, a field of fewer than 100 LeadBoaters lined up for SBT GRVL, one of the premier gravel races in the world which covers 141mi (227km) and 9,840ft (3,000m) of climbing. Among them were Peter Stetina, Alex Howes, Freddy Ovett, Ted Kind, Colin Strickland, Adam Roberge, and Unbound Gravel champion Ian Boswell.

Unlike the Leadville 100, SBT GRVL doesn’t have a major climb. Instead, the course consists of an endless amount of rollers, short climbs, and gnarly gravel sectors. The field of 1,500 was whittled down over the course of the day, and eventually, there were fewer than 10 riders remaining. One of them was Stetina, who had finished fifth in Leadville the day before. One look at his power file from SBT GRVL, and we see a graph that is eerily familiar.

Swenson – first 70km:
Time: 2:05:54
Average Power: 228w (3.6w/kg)
Normalized Power: 269w (4.3w/kg)
Climb at Kilometer 46 (avg 6.6 percent): 321w (5.1w/kg) for 8:50

For the first two hours of the race, Stetina’s average power was within a tenth of a watt-per-kilo of Swenson’s in a completely different race the day before. Both courses had similar opening terrain to start, and pack dynamics were at play while the group was still 100 riders strong.

The only major challenge of the first few hours was a steep climb at kilometer 57, which Stetina went up at just over 5w/kg. On the final section of the climb, he was pushing more than 350w (5.5w/kg) to help whittle down the front group. While these numbers aren’t hugely impressive, remember that we’re at 8,000ft (2,400m) elevation.

For the next two hours, the race was relatively calm. Stetina averaged just over 200w (3.1w/kg) and spent a lot of time coasting. Of course, the gravel roads around Steamboat Springs were not the most leisurely passes, but compared to what they’re capable of, these (ex-) WorldTour pros were taking it very easy. It wasn’t until kilometer 140 that the race heated up, as the road climbed ever so slowly towards Pinnacle Peak. Stetina – feeling the effects of the day before – admitted that he wasn’t at his best, and sucked wheels as best he could to survive. Even so, Stetina’s data showed that he was one of the stronger riders on the day.

Petre Stetina's power data from kilometers 140-167
Petre Stetina’s power data from kilometers 140-167.

Stetina – kilometer 140 to 167:
Time: 59:06
Average Power: 243w (3.9w/kg)
Normalized Power: 262w (4.2w/kg)
Final 1.9km (avg 5.7 percent): 331w (5.3w/kg) for 5:09

After five hours in the saddle, on the second consecutive day of racing, the race was won on the final few climbs of SBT GRVL. Coming out of Oak Creek, the lead group hit the first pitch. Stetina stayed in front, while others began dropping back.

Petre Stetina's power data from the Oak Creek
Petre Stetina’s power data from the Oak Creek.

Stetina – Oak Creek climb:
Time: 6:44
Average Power: 312w (5w/kg)
Normalized Power: 327w (5.2w/kg)

The next climb came at Kilometer 201, and broke the legs of nearly every rider in the group. When you consider the altitude and level of fatigue that riders are carrying into this point of the race, anything over 300w was incredible. The ability of Stetina to hold nearly 6w/kg for five minutes is what made him world-class.

Petre Stetina's power data from a climb at kilometer 201
Petre Stetina’s power data from a climb at kilometer 201.

Stetina – steep climb at kilometer 201:
Time: 4:38
Average Power: 351w (5.6w/kg)

The last climb of SBT GRVL came just a few kilometers later, and though it wasn’t as steep as the previous, it hurt just as bad. Stetina was still able to push nearly 5.5w/kg on the climb and even had the energy to sprint over the top at 13w/kg.

Stetina – final climb at kilometer 206:
Time: 5:46
Average Power: 314w (5w/kg)
Normalized Power: 325w (5.2w/kg)
Max Power: 813w (13.1w/kg)

Just because the final 13km was flat doesn’t mean it was easy. In fact, these final 17 minutes – which came over six hours into his ride – were some of Stetina’s strongest of the entire day. Pulling at over 300w and kicking over the climbs at 400w, Stetina was putting the pressure on Howes and Boswell, who were the only ones able to stay with him.

Into the final sprint, the trio was all together. Marking himself as one of the strongest on the day, Stetina got stuck on the front, and led out the sprint from a few hundred meters to go. Boswell came around him, and so did Howes, with the former American road race champion taking the victory at SBT GRVL. Stetina finished third in the sprint, and did more than enough to earn the inaugural LeadBoat title – all with a time, average and normalized power that look awfully similar to what Swenson did at the Leadville 100 the day before.

Petre Stetina's power data from the final 17km of SBT GRVL
Petre Stetina’s power data from the final 17km of SBT GRVL.

Stetina – Final 13km:
Time: 17:32
Average Power: 268w (4.3w/kg)
Normalized Power: 291w (4.7w/kg)
Final sprint: 648w (10.4w/kg) for 14 seconds
Max Power: 960w (14.5w/kg)

Peter Stetina won the LeadBoat Challenge Photo: Brad Kaminski | VeloNews.com

Stetina – SBT GRVL:
Kilometers: 225.7
Time: 6:16:45
Average Power: 230w (3.7w/kg)
Normalized Power: 262w (4.2w/kg)
Energy Burned: 5,184kJs
Elevation Gain: 2,894m (9,495ft.)

Power Analysis data courtesy of Strava and Strava sauce extension 

Keegan Swenson

Peter Stetina

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