Jacquelyn Camille Herron (born December 25, 1981) is an American ultramarathon runner. She has achieved 12 world records in ultramarathon distances.
Herron was born in Norman, Oklahoma. She was born with impaired hearing, and experienced a near-drowning incident at the age of three. She was later diagnosed with central auditory processing disorder, and has stated that she did not speak much as a child.
She began running in seventh grade, the year after the release of Forrest Gump (1994). She has said she was able to relate to Forrest Gump, not only because of the running. Over the years her husband noticed autistic traits, and through talking to a friend in Oklahoma and taking online tests, she pursued testing for autism and attention deficit hyperactivity disorder. In 2024 she was officially diagnosed with both. Herron's unusual running gait and arm swing are attributed to an extra bone in her foot and twists in her arm and femur.
She attended Westmoore High School in Oklahoma City, where she was a three-time all-state recipient in cross country, a three-time state champion in track and field, and valedictorian.
When Herron was 19, she and her family lost their home and possessions during the 1999 Oklahoma tornado outbreak. She has cited that event as a turning point in her life, motivating her to run longer distances on Sundays "to celebrate life".
After receiving academic and athletic scholarships, Herron attended the University of Tulsa, where she was a Top 10 Senior and earned a bachelor's degree in Exercise and Sports Science in 2005. While at college, she began scientific research into the reasons behind the stress fractures she had experienced as a young runner.
Herron obtained a masters degree in Exercise and Sports Science from Oregon State University in 2007. Her research focused on identifying the optimal anabolic stimulus for musculoskeletal health, emphasizing the importance of frequent light mechanical stress interspersed with infrequent high-intensity stress.
Herron returned to competitive running as a road racer under the guidance of her husband, Conor Holt, a former elite runner and college coach. She attributes her success in ultrarunning to her scientific knowledge and training approach, which prioritizes short, frequent runs to accumulate high volume consistently.
Herron has worked as a research assistant in bone imaging and osteoimmunology at the University of Oklahoma Health Sciences Center, co-authoring several scientific papers.
Herron coaches athletes and offers coaching through an online coaching program.
Herron is a three-time Olympic Marathon Trials qualifier and a 21-time marathon winner.
She competed on the 2011 US Pan American Team in the marathon, finishing 9th.
Herron set the Guinness World Record for the fastest marathon by a woman in a superhero costume, completing it in 2 hours, 48 minutes, and 51 seconds, dressed as Spiderwoman.
In 2017, she became the third American to win the Comrades Marathon.
Herron is the only athlete to win all of the IAU Ultra Road World Championships (50 km, 100 km, and 24hrs).
Since 2015, she has set multiple Ultramarathon world and American records/bests between 50 miles and 6 days.
In February 2022, she won the Jackpot 100/US 100 Mile Championship outright in 12:41:10.