Gavin Henson has been training at altitude. After a heavy Christmas schedule, he took advantage of a few free days to climb into the thin air of Chamonix. He went with Charlotte Church, a keen alpiniste in her own right.

Given that he is back at work today, playing for the Ospreys in the Heinekin Cup against Stade Francais, he might have been applauded for steeping himself in the sounds of France. A bit like Sir Clive Woodward playing 'Mae Hen Wlad Fy Nhadau' ad nauseam on the England team bus whenever it went to Cardiff.

Unfortunately for our Gav, any ripple of applause was, as ever, drowned by the clickety-click of the paps' cameras. So he found himself back in the pages of what the Welsh refer to as the London tabloids, caught in the early hours, snapped in a condition that suggested he was the worse for wear, not the better for the break.

There are two ways of looking at this. Either: here's a model pro, his body a sea-level temple, taking a little time to adjust to life in the mountains - sleep patterns disrupted, self-balancing sensors decalibrated by the paucity of the oxygen supply, bladder pinched by the cold. Or: he was pissed.

There is a problem with Gavin Henson, but it has nothing to do with his life as one half of a fast-living celeb couple. And no amount of advice to him - knuckle down, young Henson, and recognise the privilege of your position, your status as a role model, the order of your priorities - will help.

He is not playing very well. That's it. He's a rugby player out of form.

Two seasons ago he was about to make his big breakthrough. He picked up Mathew Tait and booted Wales to victory over England, the defining moments at the start of Wales's grand-slam season. In the last game of that Six Nations campaign he played outstandingly well against Brian O'Driscoll, drawing him into a personal dog-fight that completely undermined the strategic threat of the Ireland captain.

But then came the Lions tour in the summer of 2005, a horror show for everyone, and Henson in particular. The Lions tend to be a frantic exercise in assimilation and homogenisation. Henson will always be a loner.

Then, after the denting of his confidence came damage to his body, causing him to miss just about all of last season. This season he has been trying hard to re-establish himself.

Trying too hard. Some skills remain prodigious - his kicking, obviously, but also his gliding strength. Some tricks are sublime - little passes into holes without looking, delivery out of the tackle when none seems possible.

On the other hand, he has had kicks charged down. He has been caught in possession, run up a few blind alleys, popped passes into thin air. He will never be the quickest thing on two legs. And he has looked on more than one occasion as if he knows that other people know how to get to him.

For our part, on the side of the Henson-watchers, we all tend to make him the centre of attention. I've just done it again.

The Ospreys, collectively, have not kicked on as I thought they would when they became Celtic League champions at the end of 2005. At that time they were playing a brand of free-flowing rugby that set them apart. But now everyone is trying to play with less restraint and they know all about the patterns and stamina levels that go with high intensity. And everyone knows where the flaw-lines are in a game of risk.

The Ospreys, by way of response to their blocked upward path, have built a big squad, bringing in ex-All Blacks Justin Marshall and Filo Tiatia, and developing homegrown talent including James Hook.

Hook, though, is almost as enigmatic as Henson. He has gone from being the most promising youngster in the land to the midfield mystery. He has not put a finger wrong for Wales - bar a missed tackle against Canada - but rarely gets selected as a starter by his regional coach, Lyn Jones. It is as if the coach knows something that we don't. Head-on tackling? We look but see only the plus points in a player who seems to be as gifted and as cool as they come.

The Ospreys, without finding any consistent rhythm, are still in contention in the Magners League and, certainly, the Heineken Cup. Today they play Stade and Jones has decided to put Henson and Hook in tandem, the latter given the job at No 10; next week they travel to injury-ravaged Sale. Win both and they can qualify from a group that had 'stinker' written all over it from day one. Add that to the Llanelli Scarlets' double over Toulouse and suddenly the Welsh regions emerge as contenders in the big time.

Last season the Ospreys played in the same pool as Stade. They somehow even managed to win at home, although it defied belief how they held out. This season they have travelled to Paris and lost, 27-14. But actually played very well. Although Henson had a bad day.

Oh dear. It is very difficult working out the Ospreys, which of course used to be their strength. Now is the moment for them to be absolutely clear about themselves. They need Henson and Hook to take centre stage and run their show with absolute authority. Play with attitude, not mess around at altitude.