THERE are few things worse than a young player copping a serious knee injury in the pre-season, just when they are on the verge of senior selection.

But Sydney Swan Kristin Thornton knows just what it's like.

The 20-year-old West Australian, the Swans' fourth draft pick and No. 54 overall in the 2005 draft, was in exciting form in a game against Port Adelaide in late February when his left knee refused to move.

"It was similar to what happened to Nick Malceski in that I went to change direction and the knee collapsed," Thornton said.

"At the time, the knee popped out and then back in. I heard a mixture of grinding and popping noises and quickly went off to see the team doctor who told me within five minutes that I had torn my anterior cruciate ligament.

"My first thought was, ‘What am I going to tell my mum?’"

Thornton’s parents flew over the next day to be with their son as he prepared for his operation and initial recovery, with the Swans taking the traditional course.

And after 18 weeks, Thornton reached a new level when he ran for the first time on Monday.

"I actually did two five-minute runs on the treadmill and I pulled up fine today with no soreness or swelling," a relieved Thornton said.

"I was both nervous and excited about running for the first time and reassured to get through it unscathed."

Naturally, Thornton has been busy receiving physiotherapy throughout his recovery.

"I have had to do a lot of rehabilitation because initially the quadriceps muscle wouldn’t even turn on," he said. "It is amazing how quickly the muscle wastes away.

"I then did a lot of pool work and weights and have finally started to kick with my left leg so it is all heading in the right direction."

Sydney Swans strength and rehabilitation coach Bryce Cavanagh said Thornton had been an inspiration to the other players who had suffered injuries throughout the season.

"Obviously, his injury was the worst because it was season-ending but he has been really positive throughout and helped lift the spirits of the other injured players," he said.

"Next week is important in his recovery as he starts running outside and this is the period where everything is stepped up a notch in terms of functional training.

"Kristin will continue to do a lot of strength work in order to negate the imbalance in muscle weakness caused by the injury."

Thornton has not been idle in his injury, undertaking a personal training course and working diligently with the Team Swans community program – visiting junior clubs and schools, while also attending match day functions.

One community visit took him to Wollongong to help establish a Swans supporter network.

"About 80 to 100 people turned up which was excellent considering the State of Origin game was on the same night," Thornton said.

"I am sure there would have been more supporters if that match wasn’t being played but everyone was enthusiastic and positive."

Just like Thornton, who is hoping to gain full strength and mobility back in his left knee, complete a full pre-season and push for senior selection again in 2009.