To take on an audacious, difficult physical challenge is considered a gutsy pursuit. It might be a marathon or a triathlon, a long ocean swim or an all-day adventure race, but thousands of Sunshine Coasters take on such challenges each year, rising to the contest and reaching beyond their known comfort zone as humans have done for millennia.

And while these warriors may come in all shapes, sizes and ages, what is consistent is that the road is long and the training is tough. In recent times, these athletes’ petrol tanks are more and more likely to be fuelled with Infinit Nutrition, a liquid sustenance that has been formulated through an avalanche of research and testing.

The company was founded in the United States, but the Australian franchise is in the Coolum industrial area on the Sunshine Coast, with Jason and Rachael Cheshire at the helm. The couple’s own athletic accomplishments are inspiring, but it is one thing to do and another to help others. Their passion for their products and their people is plain.

“It is pretty cool to have helped do something that directly helps someone achieve a personal goal, that makes them a better athlete by mixing our products with water and drinking it,” Jason says. “We do really love that.”

The couple makes a fierce team. They have ridden some big waves together over the past decade or so – Jason has had a series of major injuries and health challenges, and working and living together is not for everyone.

But their humour, strong work ethic and camaraderie, combined with a love of their fur kids Murphy Brown and Augustus Albert, have carried them through.

Rachael, 46, a former police officer, has been running the social media and marketing arms of the business for the past eight years. But she is also in charge of sponsorship, picking and packing and dispatch. Jason says she does the work of five people.

Jason, 49, bought the franchise for Australia in 2010. He had owned a bakery in Emerald, then a motel in Hervey Bay and was introduced to Infinit by acclaimed triathlon coach Nick Croft in Noosa, as he pursued his own triathlon, mountain biking and adventure racing performance goals.

“Back in 2008 and 2009, liquid nutrition was just not a thing,” Jason says. “The standard perception was that is just wouldn’t work. People were using bars and things, but I was taking it for probably two years and never told anyone in Hervey Bay because I just did not want the negative chitchat.”

What sets Infinit apart from other nutrition solutions is that it is most often custom-made and available off the shelf.

Liquid nutrition has to provide energy, plus all the essentials such as salts and vitamins to keep a person going who is moving, sweating and stretching themselves for many hours.

“It was major for me – a game changer,” Jason says. “I didn’t have to think about taking muesli bars or gels or anything: I didn’t have to think about my nutrition plan and could just go out and train. That is massive for an athlete.”

The pair knows a lot about pushing the limits of endurance. Jason was twice selected to compete in triathlon’s blue riband event, the Ironman World Championships in Hawaii. The race is widely regarded as the pinnacle human endurance event – a 3.9-kilometre swim, 180.2-kilometre cycle and 42.2-kilometre run back-to-back – in tough, tropical conditions.

With 15 Ironman completions under his belt, as well as numerous two-day adventure races, ultramarathon and marathon events, Jason knows a lot about enduring and fuelling the body to not just cope but to finish well. Rachael, who was always into sport and fitness, was introduced to triathlons when she fell in love with Jason. She has completed numerous half Ironman distance triathlons, road marathons and half marathons, as well as ocean swims.

When Jason bought the franchise, it was a small business, turning over just $10,000 a year. The business has been growing consistently at 20 per cent a year – a rate most firms would dream of.

For the uninitiated, liquid nutrition may sound all hocus pocus. Sure, so-called sports drinks have been around and used by everyday exercisers for years, but nutrition solutions as a fuel source while on the move still seem like space-age stuff to many.

But the science is in. Studies in reputed sports journals have found performance gains because liquid empties out of the gut faster than solids, leading to quicker utilisation and avoiding the nausea that can be a huge problem for those out on a long ride or run.

Jason has networked with the nation’s premier sports dietitians, who are also former elite athletes, including Steph Cronin – former champion surf lifesaver – and former ultramarathon champion Steph Gaskell. Dieticians can assess what the athlete needs and the Infinit powder makers apply that recipe to the letter. In addition, the company has its own nutrition consultants who offer advice for free. Given no two sports are alike and no two athletes are alike, this is a boon, particularly for those who are everyday people.

“It is nothing for a customer to place 15-20 orders with us,” Rachael says. “That is a lot of money to spend and a lot of product to use, and we have to get it right when they are depending on us for their performance.”

Each year, the Cheshires select 120 sportspeople to sponsor, with most being regular age groupers just giving something physically challenging a good go. But they also have an impressive list of elites on their sponsorship books, including newly crowned Coolangatta Gold winner, Sunshine Coast-grown surf sport queen Lana Rogers. Mountain bikers, road cyclists, triathletes, surf lifesavers and trail runners all have places in their sought-after stable.

“It is just great for us,” Jason says. “We get to help build a community. We get to help sportspeople with our products. It’s a pretty good job to have.”