It’s not easy switching careers, but Heather Jackson has made it look that way.

The former US triathlon star, who boasts multiple podium finishes in IRONMAN events, took on the challenge of Unbound XL – a gruelling 358-mile ride through Kansas – and absolutely smashed it.

Her finishing time of 20:57:57 smashed the previous women’s record of 22:25:15, set by Cynthia Frazier in 2022, and placed her eighth overall, ahead of most of the men in the field.

Heather takes in incredible achievement

In an emotional Instagram post, she said: “Honestly still processing. There were about 15miles to go and I literally wasn’t sure I could make it. I legitimately couldn’t hold my head up any longer and there were zero calories left in the tank.

“But we had crossed routes with the 50mile racers and their (your) cheers helped me keep pushing.🥹🤗 THANK YOU. Thank you to everyone who has sent notes of support- I’m reading them all❤️

“Thank you to my female competitors for pushing me all day- it was an honor to race with you. The biggest congrats to everyone who not just finished the XL, but who even dared to start it. That was truly next level.”

The 41-year-old Jackson, from New Hampshire, spent nearly 21 hours in the lead after storming to the front of the XL peloton, racing at more than 17 miles per hour.

And it’s certain that her time spent competing amongst the elite on the triathlon circuit helped her enormously after she decided to switch to gravel racing and ultra-endurance trail running in 2022.

Ruth Astle on Unbound experience

Three-time IRONMAN winner Ruth Astle, 35, also took part in Unbound, finishing in the top 50 elite women for the 200-mile race.

Ruth wrote afterwards on Instagram: “47th. The position really doesn’t tell the whole story though. . . Things I learnt from Unbound:

“- the spirit of gravel is alive and well – when I didn’t get my carbs at Feed 2 had 3 separate people offer me some spares which helped me survive that 120km
– the difference that locals embracing the event makes – the atmosphere in Emporia compared to Kona is miles apart and makes the whole event so much more enjoyable
– I have a lot to learn in terms of racing – how to move up at the right time to be in the right position, how to hold my space when others trying to move up
– Unbound is for sure the Kona of gravel – the heat, the wind, the long rolling gravel roads!

“Despite not being the race I hoped for, I had a great time managing to catch up with some sponsors, meeting new people, catching up with friends and riding proper American gravel

“Not sure when but Unbound I will for sure be back in hope for a bit of a smoother race to see what these legs can do!”