SHE won her first Scottish athletics titles before Sir Chris Hoy got his first BMX bike and before either Liz McColgan or Paula Radcliffe had won a championship medal, but Hayley Haining is still living the marathon dream.

She has outrun these three, and many more.

The qualifying time for next year's Commonwealth Games (2hr 40min) will be in her sights when she contests the Virgin London Marathon tomorrow. Kilbarchan coach Derek Parker believes she can manage 2:36. Haining laughs, and says "Derek should shoosh, and be a wee bit more conservative."

Haining will be 42 come Glasgow 2014, and would be the oldest runner to represent Scotland at the Commonwealth Games. Lorna Irving was 39 when sixth in 1986.

Her London debut at the distance, in 2005, booked a world championship place in Helsinki, and a Commonwealth berth for Melbourne. In Finland, Haining, Radcliffe, and Mara Yamauchi (also now retired) took World Cup bronze. In Melbourne, still recovering from a virus, Haining was ninth, but ran 2:31 when second in Dublin later that year. It would have won bronze in Melbourne, but she says conditions in Ireland were far more benign.

A clinical pathologist in veterinary medicine, Dr Haining now savours a final Games chance and the opportunity of giving her son a unique memory.

Her second London appearance (2:29.18, in 2008) saw her named Olympic reserve to Radcliffe, who ill-advisedly ran in Beijing, and the Scot was left in limbo.

Haining was a prodigious talent at Nith Valley in the 1980s. She won her first cross-country race, an open event in Edinburgh, aged 11, then took both the Scottish junior girl and Scottish schools 800m titles in 1985.

Haining's son, Elliott, is approaching three, "but looks four," she says. A budding javelin-thrower, says dad. Less than two inches short of two feet at birth, he was delivered by emergency section.

Marathon history is replete with tales of iron-woman endurance: Ingrid Kristiansen winning here 31 years ago, oblivious to being four months pregnant; McColgan training 12 days after giving birth. "It wasn't like that for me," confides Haining. "I'd a very difficult pregnancy. I was very sensitive to the hormones, so my ligaments started to loosen up very quickly. I'd grandiose ideas of running through it, like you read in magazines. I was about one week pregnant, and I was ill. I had delusions of adequacy.

"I had a migraine every day for five months, and if it was not a migraine, it was downgraded to a very sore headache. I look down a microscope most of the day, so that was difficult. And I'd nausea for nine months. I also had insomnia. But the minute Elliott popped out, him and I have been best friends. You can't imagine that when you really feel so bad. I felt age had caught up with me. I was so hunched over, could not stand straight, and was tilting to the right. My posture was shocking. I've done lots of exercises to get my shoulders set back again, standing straight, getting my tummy and gluteal muscles to work again. Having had my tummy muscles cut, I was lifting this big boy, and became very hunched and round-shouldered.

"My back was so sore that I had to get it sorted out, even to be able go to work. As I did that, my running got better." The Edinburgh marathon last May was her first in almost three years. "By halfway, I knew I was drying out. The last six miles I was falling apart. All that kept me trotting along was that my parents were with Elliott at the finish, and that was my lift back to the car. If I'd pulled out, they weren't going to get me for hours. I finished in 2:45, burned to a cinder with sunstroke.

"I'd done not too badly, considering the state I was in. It was a big landmark. It let me know I still loved the big-marathon day, the atmosphere. It did its job. I'd had a wee boy, but it was still all there.

"I decided to go for 2014 as soon as I was pregnant. I worked out that Elliott would be about four, and able to remember everything. I was 14 when the 1986 Commonwealths were in Edinburgh. I remember sitting with sprinter Kath Lithgow – my first time in that cauldron atmosphere. We shouted ourselves hoarse, and Yvonne Murray [future Commonwealth and European champion] was third. I think every hair on my body was standing on end. I'd met Yvonne at a Scottish schools' training day and we went on a run. I felt I knew her. So to see that in Edinburgh – the impact was huge.

"And I thought it would be amazing having my own wee one in the crowd, seeing me do that."

She is in the club race tomorrow, not the elite field. "I need to go out with conviction from the start. My recent half marathons suggest between 2:36 and 2.40. The feeling of goodwill spills on to the road. If you harness it, that can carry you home.

"If it doesn't happen, I'll try again in the autumn. I won't do another spring marathon. I don't mind the rain – it's when the snow comes down, the ice. You have to organise the wee one, and what dad is doing, as well."

So is dad left holding the baby when mum trains? "Yes and no. Willie also works at the vet college, but he's away a lot. I use a ski machine when Elliott is in bed. When Willie is at home, I'm often out as soon as it's light, and home before anyone is awake. Some nights we pick Elliott up at the nursery. Willie drops me off, and I run the last five miles home. He will be just getting the dinner on as I get in the door. So I'm not giving him all that much credit."