"I like doing anything with adrenaline," he said. "I've always been very keen on sport but never particularly good."
What he does do well is mend knees and ankles.
And as orthopaedic surgeon to the stars, he has put millions of pounds worth of football talent back on the pitch.
Bollen's name may not rank alongside Gary McAllister or Niall Quinn but the Bradford-based doctor is feted just as highly in Premiership circles.
Pictures of McAllister and Quinn stare proudly from his office in the Yorkshire Clinic in Bingley, part of the wall of fame of players he has repaired.
He said: "When you look at the last England squad Eriksson produced, I've treated or operated on eight out of 30.
"Presumably that proves the results I get are quite reasonable! Because I operate on so many players from different clubs, when Match of the Day or Sky is on I sometimes sit there thinking: `I've fixed him, and him and him ...
"I suppose I live out my sporting ambitions vicariously by watching the players I've treated running around again."
McAllister did more than just run about last season - his renaissance in Liverpool colours was the driving force behind their treble triumph and included a man-of-the-match display in the UEFA Cup final.
Wes Brown, Lee Sharpe, Jordi Cruyff and Les Ferdinand are other success stories as well as rugby league's Nathan McAvoy and Martin Wood from Keighley Cougars.
There is no more certain adrenaline rush than treating the superstars on telephone wages.
He laughs: "I suppose you have to have the big match temperament and put into the back of your mind the fact that the leg you're holding may be worth £7.5 million.
"To a certain extent when you are treating professional sportsmen, you're only as good as your last operation.
"If you do have one that went wrong, you may not survive. But it has worked so far.
"I would stress I'm not a miracle worker and no operation, whoever does it, has a 100 per cent success rate."
Bradford City fan Bollen has looked after the club since 1992 but also works with nearly half the Premiership as well as all the local rugby clubs.
"I care very much about what I do whether I am operating on a Premiership player or an amateur footballer who came to me with a ruptured anti-cruciate on the national health," he said.
"The only thing that irritates me is when clubs send players across to America for treatment. There are surgeons in this country just as good.
"About a dozen of us around the country treat a significant number of sportsmen. I feel we do a good job and ought to fly the flag."