Y ou would need a lot of power in your shoulders to shrug off the kind of adversity Samantha Kinghorn had to deal with when she lost the use of her legs almost three years ago, but far more still to perform the kind of feats she has lately been achieving at the elite level of wheelchair racing.

The Borders teenager was just 14 when she was struck by snow falling from a roof near her home. Almost immediately, she realised her back was broken, but the testimonies of those who shared time with her over the six months she spent in the renowned Spinal Injuries Unit at Glasgow's Southern General Hospital suggest that she accepted the hand life had dealt her just as quickly and showed a stirring determination not to waste her days on self-pity.

Nor was she ever likely to bottle up the energy she had previously channelled towards gymnastics, ballet and even, briefly, rugby. "I did loads of sport," she says. "Living on a farm I just ran around all the time. I'd try my hand at anything. I just enjoyed being outside all the time; I'm not an inside kid at all."

Kinghorn, now 17, is sitting at the kitchen table of her home near the Berwickshire village of Gordon. Bright-eyed and with a mischievous wit, it is not her disability that is striking, but her competitive fire. Yes, she has been through a life-changing event. But it is the life she focuses on, not the change.

After a physiotherapist at the Southern General took her to Stoke Mandeville, the national centre for disability sports, where she was able to try a range of activities, wheelchair racing became her new passion.

Hence the punishing regime of early-morning training sessions that see her flying along the Borders roads in her racing chair six days a week. She says she is lucky to live in such a quiet corner of the world, although her father Neil might question his good fortune as he pedals along beside her on his bike. A gifted engineer, he has made up a set of rollers for her to train on during the winter. It is not clear whether this was an expression of paternal love or simply a desire to get an extra hour in bed.

Next weekend, Kinghorn will be racing in the 100m, 200m, 400m and 800m in the Swiss Junior Championships at Nottwil, just north of Lucerne. As a purpose-built wheelchair track - which has a harder surface than a standard running track - the competition attracts some of the world's best parasport athletes, so she will be able to gauge her progress against the competition she will have to face at next year's Commonwealth Games in Glasgow and, in all probability, in Rio in 2016.

"What Sammi has done in the past 16 months is phenomenal," says Ian Mirfin, her coach at the famous Red Star disability sports club in Glasgow. "She's knocking on the door of the world's top 10 and she's currently No 2 in Europe. She's working hard and is attracting a lot of interest at British level."

Kinghorn faces a busy autumn of road racing, which she says she prefers, but next year's Commonwealth Games loom large on her personal horizon. Her specific target is the 1500m final on July 31, although she knows she will be at a disadvantage as the event is in the T54 category, for athletes who have full abdominal muscles, while she is categorised T53 due to the position of her spinal injury.

"Obviously, it's not the best, but I got the qualifying time so I'm going," she smiled. "It will be hard for me to compete against the stronger athletes because I don't have that extra power going down through the chair, but if I get to the final I will be really pleased. I just really want to compete in my own Games.

"I went to the London Games last year. I remember when David Weir came into the stadium and how the place just went wild. I was only watching, but I had goosebumps just being there. I just immediately thought, yes, this is what I want to do. I want to have this.

"I suppose Rio is what I'm really targeting, because I can race in my own T53 category there. But I'm still excited by the Commonwealths because I'll get that home crowd thing as well. If I can handle that then I'll know I can handle anything."

As she can already handle 6am starts and the experience of hurtling down hills at close to 50mph, then a little bit of pressure from the crowd should not be too much of a problem. Her immediate concern this week is Catherine Debrunner, the Swiss racer who is the only woman ahead of her in the European standings at the moment.

"She's the one I need to beat," says Kinghorn. "She kind of sets the standard. But it's really all about getting experience for me. I want to get my times lower and lower over the next year and I need to get used to race tactics as well.

"Above 800m, you move out of lane. Then, it's all about drafting [slip-streaming] when you all go in a long line because of air resistance. Sometimes, people try to box the best racers in and I have to know how to deal with things like that. These are things I'm still learning because I'm relatively new to it all."

Having just left school, Kinghorn will spend the next year as a full-time athlete. She will come under the wing of the East of Scotland Institute of Sport, while financial support comes from a handful of small, and mostly Borders-based, sponsors. However, with a full racing kit of chair frame, wheels and tyres costing around £12,000, the money goes quickly.

Which is, of course, an inconvenience. But, all things considered, a rather minor one.