THE FITTEST 50
Every sport makes different demands, but success at each often hinges on conditioning. Which athletes were best prepared in 2018? SI picked—and ranked—them
MEN
1 SAQUON BARKLEY
Giants Pro Bowl running back
IF THERE was a rookie milestone to clear in 2018, you could count on Barkley to hurdle it. With breakout speed, punishing power and acrobatic moves—and those muscular quads—the 21-year-old workhorse became only the third first-year back to eclipse 2,000 yards from scrimmage.
2 CRISTIANO RONALDO
Five-time Ballon d'Or winner
3 GIANNIS ANTETOKOUNMPO
Two-time NBA All-Star
4 NOVAK DJOKOVIC
Winner of 14 tennis majors
5 KEVIN MAYER
Decathlon world-record holder
6 MAT FRASER
Three-time CrossFit Games champion
7 LEBRON JAMES
Four-time NBA MVP
8 JORDAN BURROUGHS
Wrestling gold medalist
9 CONOR MCGREGOR
UFC fighter, featherweight and lightweight; boxer
10 CANELO ÁLVAREZ
Multiweight boxing champion
11 AARON DONALD
2017 NFL Defensive Player of the Year
12 LUKA MODRIĆ
2018 Ballon d'Or winner
13 RUSSELL WESTBROOK
2017 NBA MVP
14 PATRICK LANGE
2018 Ironman world champion
15 TOMMY CALDWELL
Free-solo rock climber
16 KJELD NUIS
Two-time speed skating gold medalist
17 GIANCARLO STANTON
Yankees All-Star outfielder
18 PATRICK MAHOMES
Chiefs Pro Bowl quarterback
19 HAMISH BOND
World champion rower, cyclist
20 CONNOR MCDAVID
Oilers All-Star center
21 ELIUD KIPCHOGE
Marathon world-record holder
22 CAELEB DRESSEL
Two-time swimming gold medalist
23 JIM WALMSLEY
U.S. ultrarunner
24 GERAINT THOMAS
2018 Tour de France winner
25 BROOKS KOEPKA
World No. 1 golfer
WOMEN
1 SIMONE BILES
Four-time Olympic gold medal gymnast
SHE MAY only stand at 4'9" but the world's most decorated gymnast towers over the competition. After time away in 2017, the 21-year-old Biles returned to rule the sport again with an unmatched mix of muscle and mettle. At the world championships in Doha, Qatar, in November, she set the record for career world titles among men and women, with 14, including four more gold medals—all while suffering from a painful kidney stone. An all-around champion, indeed.
2 CATERINE IBARGUEN
Colombian triple jumper
3 TIA-CLAIR TOOMEY
Two-time CrossFit Games champion
4 DINA ASHER-SMITH
British world champion sprinter
5 GWEN JORGENSEN
2016 Olympic champion triathlete, marathoner
6 KATIE LEDECKY
U.S. gold medal swimmer
7 AMANDA NUNES
UFC bantamweight, featherweight champ
8 DANIELA RYF
Four-time Ironman world champion
9 EMMA COBURN
2017 steeplechase world champion
10 SERENA WILLIAMS
23-time major tennis titlist
11 BREANNA STEWART
2018 WNBA MVP
12 COURTNEY DAUWALTER
American ultrarunner
13 CASTER SEMENYA
Two-time 800-meter gold medalist
14 MARY KEITANY
Kenyan marathoner
15 EMILY REGAN
Four-time rowing world champ
16 HILARY KNIGHT
U.S. ice hockey Olympic champion
17 KAILLIE HUMPHRIES
Two-time bobsled gold medalist
18 MIKAELA SHIFFRIN
Reigning World Cup ski champion
19 SASHA DIGIULIAN
U.S. rock-climbing champ
20 LINDSEY VONN
Four-time World Cup ski champion
21 MAGGIE STEFFENS
U.S. Olympic water polo champ
22 CAROLINE WOZNIACKI
2018 Australian Open winner
23 JESSIE DIGGINS
Cross-country skiing gold medalist
24 JULIE ERTZ
U.S. soccer World Cup champ
25 CLARESSA SHIELDS
Two-time Olympic boxing gold medalist
THE EXPERTS
MICHAEL JOYNER
Human performance expert, Mayo Clinic
SUE FALSONE
Physical therapist, athletic trainer and author
CHRISTOPHER LUNDSTROM
Exercise physiologist, coach of elite distance runners
DAVID HESSE
Vice president for performance, IMG Academy
ROY HOLMES
EXOS performance manager, CSCS
THE CRITERIA
With the help of a panel of experts (opposite page), athletes were ranked based on their performances over the last 12 months, the demands and risks of their sport, durability, training regimens, and physical benchmarks including power, speed, strength, agility, endurance and flexibility.
FOR MORE ON THESE INCREDIBLE ATHLETES, GO TO SI.COM/FITTEST50