FIONA MATHESON reacts warily when the concept of this column is explained to her.

"I don't want to sound big-headed," she says, apparently appalled by the notion that her achievements might be portrayed as something special. "I just run because I enjoy it and if that encourages other people to do it then that would mean everything to me."

Yet for all her protestations, aspiring runners could hardly hope for a more inspirational figure than the 50-year-old from Falkirk. Currently the holder of two world records in her age category – outdoor 10k and 3k indoor – and a competitor in last weekend's BUPA Great Edinburgh Cross-Country, the mother-of-five developed from being a recreational runner taking part in her first 10k to completing a sub 1hr 30min half-marathon in just a year. That's right, 12 months.

As recently as nine years ago, though, her running was restricted to chasing children, but then a combination of serendipity and her own curiosity changed her life irrevocably. Nursing a coffee at Grangemouth Stadium as Hayley and Anna, her two youngest children, took part in an athletics session, Matheson noticed a group wearing T-shirts with jogscotland emblazoned on the front and resolved to find out more about the recreational running programme which has welcomed 20,000 people since its launch in 2002.

"I remember my first night," she says, smiling at the memory. "They asked which of us thought we could run a mile and I thought 'no way' so they put me into an easier group, but after a while you get to that mile and it kind of clicks into place. Next thing you know you are at two miles, three miles, four miles and suddenly you've got an incentive."

Within weeks, she was on the starting line of her first 10k and reassuring herself that she could haul herself around the course. Doing so without slowing to a jog would be a small victory, and breaching the hour barrier a huge success. "When I came over the line and saw it was 59 minutes, my hands shot up into the air," she says. "I might not have won the race but I felt like I had because I'd achieved my goal."

It was at that point that things began to get a little silly. Flush with her achievement, Matheson sat down with a little notebook and pen and began to scribble down ideas for what she could do next. Another 10k? Perhaps she could try to shave a minute off her time? Or maybe even five minutes if she picked the right course and trained hard?

"I wondered if I could do a 10k in under 40 minutes," she says, pausing to listen to the startled reaction. "I know that was a big jump, and my husband tried to talk me out of it, but I was determined to try it and six months later I did the Stirling 10k in 39 minutes."

So she slashed 20 minutes from her personal best in just six months? "Yeah. I just believed I could do it and trained maybe four or five days a week. I'm a big believer that you get out what you put in and if I hadn't succeeded then at least I'd tried it."

At that stage, Matheson was not even affiliated to an athletics club – "I just thought it was for people who had been running for years" – but was immediately inducted into Falkirk Victoria Harriers and first represented the club six months later in the Alloa half-marathon, completing the course in a startling 1hr 28min. "When you're in these races it's not about positions – although it's nice to finish in a good place – it's about your time and beating the target you set yourself, and I was aiming for 90 minutes," she explains. "Even now, I don't stand on a start line and think 'I'm 50, I'll have to be less ambitious' because I think that makes me try that little bit harder."

It is all a far cry from the girl who hated running at school. "No wonder I didn't like it," she exclaims. "You put on plimsolls and it was absolutely freezing wearing these little shorts and T-shirts in the snow. I just wanted to be inside in the warmth, which is why I was more into swimming. I was in the school team but I couldn't perfect the racing dive, maybe because I had a fear of belly flopping or something, but I think if I'd persevered I'd have got there."

Beyond that, her sporting background did not extend beyond brief flirtations with various keep fit and aerobic disciplines. "I wasn't sitting on the couch the whole time, but I have five kids so I just struggled to find time. What I've since realised, though, is that you make time if it is something you really want to do for yourself, and I'm really quite proud that I've had the determination to do all this. Even I sometimes I wonder 'has this really all happened?'"

It has, even if Matheson is too modest to say so herself.