Last week, Sports Illustrated unveiled its list of the 50 fittest athletes in the world. Using a panel of authorities from exercise physiologists to trainers, athletes and performance experts, the top 25 men and women, respectively, were selected based on their overall performances in 2018.

To fully evaluate each athlete, SI analyzed their durability, training regimens, the demands and risks of their sports and other physical criteria. We couldn’t help but notice that of the 50 named, eight were running superstars (not including triathletes). And, not for nothing, but six of those were females (hell yeah!).

Here’s a look at which pavement pounders made the list and what makes them so remarkable, starting with the Coconino Cowboys’ own Jim Walmsley:

Jim Walmsley – No. 23

Ultrarunning

It’s hard not to be in awe of Jim Walmsley’s laundry list of accomplishments and what seems to be his innate ability to crush it whenever he’s in a pair of running shoes. The 28-year-old ran more than 4,000 miles last year—that’s not only typical for him but means, on average, he’s running around 333 miles a month. Yes, chew on that for a minute. On top of that, he set a course record at the Western States 100-Mile Endurance Run, finishing in 14 hours and 30 minutes. He also placed first at the Lake Sonoma 50 in 5:51:16, beating his 2016 title by 9:36.

Eliud Kipchoge – No. 21

Marathon

Two hours, one minute and 39 seconds—that’s what it’ll take to beat the fastest marathoner ever in the world. Thanks to Eliud Kipchoge’s record-breaking race in Berlin last year, distance running has been forever changed, and calling him “fit” is an understatement. The 5’6” runner has an above-average exercise capacity thanks to his high lactate threshold and an impressive VO2 max. He’s a beast in a 115-pound frame. With the 2019 Virgin Money London Marathon already in the books, the 34-year-old Kenyan doesn’t look like he’s slowing down any time soon (literally). Could 2019 be the year we finally see a sub-2:00 marathon?

Mary Keitany – No. 14

Marathon

Mary Keitany makes running look easy—that is, if you consider running the second half of a marathon in 66:58 easy. Last year she outkicked second-place finisher Vivian Cheruiyot during the 2018 TCS New York City Marathon by 3:14, breaking the tape in 2:22.48. This was her fourth win at the event and her time was the second-fastest in the race’s history. Keitany also became the women’s-only record holder at the 2017 London Marathon with a time of 2:17.01.

Caster Semanya – No. 13

Track and Field

When it comes to the 800 meters, Caster Semenya is a force to be reckoned with. Last year, the two-time Olympic gold medalist had a 9-0 record and ran the fourth-, sixth- and eighth-fastest times in history. However, with her success has come controversy. Semenya has a condition called hyperandrogenism which produces an excessive level of testosterone in females. Last April, the International Association of Athletics Federations announced new regulations that could prevent female athletes with the condition from competing in specific events unless they reduce their T levels or compete against men if they choose not to alter their body’s chemistry.

Courtney Dauwalter – No. 12

Ultrarunning

Courtney Dauwalter was most likely the girl on the playground who was challenging the boys to competitions and beating them with ease. The badass ultrarunner is not only known for her stamina and strength but for outperforming some of the best runners in the world—male or female. Last year alone, she participated in 12 ultras including the Ultra Trail Mount Fuji 100-miler, Western States 100-miler and the Tahoe 200 Endurance Run. But it was her 2017 race at the Moab 240 that made us sit up and take notice as she finished 10 hours before her closest competitor (male or female) with a time of 58 hours.

Emma Coburn – No. 9

Track and Field, Steeplechase

Easily on our shortlist of the most talented athletes in running, Emma Coburn is pretty much track and field royalty. The American steeplechaser and two-time Olympian and medalist has been stacking up national titles since 2011—seven, to be exact. Although losing her American 300m steeplechase record to Courtney Frerichs last year, we have a feeling this year will be even bigger for the elite and we’ll be seeing her in Tokyo come 2020.

Gwen Jorgensen – No. 5

Marathon

Triathlon’s darling, Gwen Jorgensen, left the sport in 2018 to pursue a new challenge: the marathon. As a triathlete, Jorgensen became the first American to win a gold medal in the event at the 2016 Olympics. Now, her Olympic dreams look a little different as she pursues a gold for 26.2 miles. Even after a disappointing 11th-place finish at last year’s Bank of America Chicago Marathon in 2:36.23, the 32-year-old is ready to hit the ground running alongside coaches Jerry Schumacher and Olympian Shalane Flanagan.

Dina Asher-Smith – No. 4

Track and Field

Britain’s Dina Asher-Smith is a world leader in the 100-, 200- and 4×100-meters, securing wins in each event during the European Championships last fall. In 2017, Asher-Smith suffered a broken foot, ending her attempts at a title during the IAAF World Championships in London. Coming back strong in 2018, the now-23-year-old is back to the track with renewed strength and speed. Although she faces strong competition in her events (including fellow track superstars Elaine Thompson, Shaunae Miller-Uibo, Shericka Jackson), we bet she has a few more tricks up her sleeve for 2019.