Such is the nature of athletics that almost every one of these intent souls carried with them a history of injury. And there in the midst of them, warming down after her 800 metres race in the huge edifice alongside, was a runner with a more interesting history than most.
Twice in the last three years, Kelly Holmes has been ranked as the world No 1 at 1500 metres, only to fall prey to injury as the big championships came around.
She ran the 1996 Olympic final with a stress fracture, finishing an agonising 11th. The following year, a strong favourite for gold in the World Championships in Athens, she stepped off the track midway through her opening heat with an Achilles tendon injury so serious it jeopardised her career.
She returned at the tail end of last season to defend her Commonwealth 1500m title, salvaging a silver medal. Since then she has raced sparsely in an effort to arrive at next month's World Championships in Seville in shape to do herself justice. To that end, she has trained intensively in Madrid for the summer, partly to acclimatise herself to the 100F temperature in which the championships will take place.
Wednesday night's run in the Paris Golden League meeting was her first against a truly world class field for nearly two years. She finished sixth, behind the likes of the former world champion Maria Mutola and double Olympic champion Svetlana Masterkova. But the most important thing for her was the sense that she was moving in the right direction once again after what was only her third race of the season.
As she looked around the warm-up area, she appeared happy just to be a real part of things again. "This is what it's all about," she said. "It's not just running against a good field again. It's all the things that go on before the race, and after. You do forget. I'm so pleased that I'm back."
If gold medals were given out for determination - or, indeed, injuries - then Holmes, now 29, would have more than she knew what to do with. Years ago, as Corporal Holmes, PTI instructor in the Adjutant General's Corps at Aldershot - she regularly demonstrated her fortitude knocking Paras into shape on assault courses. She had qualified for that role by coming through a gruelling selection process which included hauling chained logs across rough terrain in a six-man team while wearing full combat gear. Only 13 of the 35 taking part went through. Only one was a woman.
"Kelly is the most single-minded athlete I've ever met in my life," said Joe Dunbar, the physiologist who has taken over direction of her training in the last nine months from the man who coached her since her childhood, Dave Arnold.
That is some compliment, because Dunbar - a former British international miler - has worked with Olympic or world champions in seven sports. His clients include the British rowing squad, the Aston Villa and Charlton teams, Manchester United goalkeeper Mark Bosnich and heavyweight boxer Lennox Lewis.
As he watched Holmes's lightweight, but strong figure, set off on another easy warm-down lap, Dunbar tried diplomatically to indicate the new direction in which he has been attempting to steer her.
The common perception of Holmes among many athletics observers is that of an athlete with unrivalled willpower and courage who has constantly pushed her body too far in her fierce desire to prove herself. Fair?
"Let's put it this way," said Dunbar with a faint grin. "In boxing, or rowing, or football, or any sport, the important thing is to peak for the really big occasions. Manchester United do exactly that in the course of a season - they step up their physical conditioning to fit in with the Champions' League. It seems such a basic, obvious thing to do - but it isn't always done. The whole aim with Kelly this year is for her to be ready in Seville in five weeks' time."
Holmes has assembled a team of people who are helping her towards that end - apart from Dunbar, she relies on massage from Wes Duncan and is a regular visitor to Ireland to see Gerard Hartmann, the physical therapist who has rehabilitated a host of leading athletes after serious injury, most notably Liz McColgan.
This weekend Holmes hopes to come even closer towards punching her full weight when she competes in the CGU World Trials and AAAs Championships in Birmingham, where two years ago she looked ready to become a world- beater.
"I've changed as an athlete," Holmes said. "I look at things more carefully now. I just don't want to get injured again. Joe holds me back in training now. Too much sometimes! No, that's just a joke..."
The old, self-destructive urge still lurks somewhere inside her, you sense. But she is fighting, fighting, fighting it.
"I don't think about the past," she said, with a strangely shy grin. "What's happened has happened. I can only hope that things go right for me now. Athletics is a funny sport - you never know what's round the corner. But I've still got dreams and goals..."