Mark Colby
ID 82883
Born : 1968 Cat. M55 Ultrarunner since 2002 USA
50
DUV-index ?Largest integer N such that the runner has at least N credited races of at least N km.
53
DUV-index+ ?Largest integer N such that the race distances provide at least N complete segments of N km in total. A single long race may therefore contribute several segments. See the DUV-Index tab for the detailed calculation. calculation details
1
Countries visited ?USAUnited States
28,3%
Rank quotient ?This runner's calculation uses 56 eligible race(s): Σ(rank − 1) = 1 535; Σ finishers = 5 420. 1 535 / 5 420 × 100 = 28.32%. A win adds 0 to the numerator. Lower is better.

Totals

Ultras completed56
Km — ultra races4 874 km
> 100 km14
> 160 km14
Longest race160,9 km
44th Wasatch Front 100 Mile — 8/9/2023

Km per year (ultra races)

211
3 races
2022
261
3 races
2023
50
1 race
2024
130
2 races
2025
50
1 race
2026

Race types (share of distance)

Trail100,0%

Wins & podiums (ultra)

🏆 Win4
🏆 Win M5
🏅 Top 310
🏅 Top 3 M12
Longest winning streak2
Current streak0

Records

50 km4h00'1950 mi8h44'12100 mi24h39'2212 h78,46 km

HISTORY

56 race(s)
DateRacePerf.Rk
2026
28.02 50km USA8th Grandmaster Ultras 50 km Run 6:08:00 h2 🥈
2025
14.06 50mi USA29th Snow Peaks 50 Mile Trail Run 15:47:02 h130
01.03 50km USA7th Grandmaster Ultras 50 km Run 5:56:00 h1 🏆
2024
17.02 50km USA6th Grandmaster Ultras 50 km Run 6:08:00 h1 🏆
2023
08.09 100mi USA44th Wasatch Front 100 Mile 34:50:58 h155
10.06 50km USA8th Sinks Canyon Rough & Tumble Trail Runs 9:19:54 h68
10.02 50km USA5th Grandmaster Ultras 50 km Run 6:39:23 h1 🏆
2022
11.06 50km USA7th Sinks Canyon Rough & Tumble Trail Runs 7:04:39 h19
06.05 50mi USA12th Salt Flats 50 Mile 11:13:54 h17
11.02 50mi USA4th Grandmaster Ultras 50 Mile Run 10:06:08 h2 🥈
2021
18.09 50km USA5th Crimson Canyon 50 km Ultramarathon 6:20:18 h8
2020
26.09 50km USA4th Crimson Canyon 50 km Ultramarathon 6:21:21 h5
2019
28.09 50mi USA3rd Crimson Canyon 50 Mile Ultramarathon 11:43:21 h4
22.06 50km USA4th Sinks Canyon Rough & Tumble Trail Runs 6:19:19 h17
13.04 50km USA16th Desert Rats Trail Running Festival 50 km 5:37:50 h38
2018
29.09 50mi USA2nd Crimson Canyon Ultramarathon 10:44:46 h3 🥉
07.09 100mi USA39th Wasatch Front 100 Mile 31:40:25 h84
11.08 55km USA4th Skyline Mountain Marathon 55K 7:06:51 h9
23.06 50km USA3rd Sinks Canyon Rough & Tumble Trail Runs 6:07:53 h9
04.05 50mi USA8th Salt Flats 50 Mile 9:07:04 h4
2017
14.10 47mi USA1st Crimson Canyon Ultramarathon 11:07:56 h2 🥈
19.08 55km USA3rd Skyline Mountain Marathon 55K 7:23:12 h16
24.06 12h USA5th Dizzy GOAT 12 Hour Trail Run 78.455 km18
2016
20.08 50km USA2nd Skyline Mountain Marathon 50K 6:37:52 h19
04.06 50mi USA20th Snow Peaks 50 Mile Trail Run 11:39:39 h56
29.04 50mi USA6th Salt Flats 50 Mile 8:44:12 h4
2015
15.08 50km USA1st Skyline Mountain Marathon 50K 6:16:52 h6
25.04 50mi USA5th Salt Flats 50 Mile 9:31:52 h10
07.03 50km USA6th Red Mountain 50K 6:09:26 h13
2014
14.06 100mi USA2nd Bryce 100 Mile Trail Run 29:14:53 h27
26.04 50mi USA4th Salt Flats 50 Mile 9:38:34 h1 🏆
2013
06.09 100mi USA34th Wasatch Front 100 Mile 32:03:46 h106
2012
07.09 100mi USA33rd Wasatch Front 100 Mile 29:06:58 h72
11.08 50km USA6th El Vaquero Loco 50K Mountain Race 6:54:00 h13
11.05 100mi USA1st The Zion 100 Mile Run 24:39:22 h15
2011
09.09 100mi USA32nd Wasatch Front 100 Mile 28:00:47 h40
30.07 50km USA4th Speedgoat 50k 7:26:33 h33
04.06 50mi USA15th Snow Peaks 50 Mile Trail Run 10:43:26 h23
23.04 50km USA3rd Red Mountain 50K 5:17:59 h17
2010
23.10 50km USA5th Goblin Valley Ultra 50k 4:00:19 h13
10.09 100mi USA31st Wasatch Front 100 Mile 28:35:56 h50
05.06 50mi USA14th Snow Peaks 50 Mile Trail Run 13:47:16 h118
29.05 50km USA2nd Sapper Joe Trail Race 5:07:52 h3 🥉
2009
12.09 100mi USA30th Wasatch Front 100 Mile 29:36:58 h59
18.07 50km USA2nd Speedgoat 50k 7:33:00 h15
21.03 50km USA1st Sapper Joe Trail Race 5:30:16 h8
2007
08.09 100mi USA28th Wasatch Front 100 Mile 28:32:25 h30
24.03 50km USA2nd Antelope Island Buffalo Run 50 km 4:57:59 h3 🥉
2005
29.10 50km USA1st Goblin Valley Ultra 50k 4:15:10 h5
10.09 100mi USA26th Wasatch Front 100 Mile 27:38:05 h33
04.06 50mi USA9th Snow Peaks 50 Mile Trail Run 10:53:00 h19
2004
11.09 100mi USA25th Wasatch Front 100 Mile 30:15:00 h36
05.06 50mi USA8th Snow Peaks 50 Mile Trail Run 10:04:28 h25
2003
06.09 100mi USA24th Wasatch Front 100 Mile 27:44:38 h24
07.06 50mi USA7th Snow Peaks 50 Mile Trail Run 10:08:46 h24
2002
07.09 100mi USA23rd Wasatch Front 100 Mile 31:41:04 h58