Don't let them see you sweat: Why Murdoch and other powerful men shouldn’t exercise in public

This week, 80-year-old Rupert Murdoch faced up to the greatest crisis of a career that began as a 22-year-old heir to the Adelaide News.

After spending the death days of the News of the World wandering around the Allen & Company media conference in Idaho, he flew into London on Sunday morning to grasp the wriggling body of News International by the scruff and try to control the scandal.

But, rather than adopting a no-sleep-till-Brooks-goes approach to dealing with it, the News Corporation chairman has been keen to stick to the daily fitness routine said to be encouraged by his wife Wendi Deng. Murdoch emerged from his London flat on Monday and Tuesday mornings with his personal trainer to be put through his paces in the glare of Kensington Gardens.

Inevitably, pictures of the media baron stretching and jogging made it into the press, but an offshoot of these workouts is that perhaps the photograph that will pass into legend from this whole grubby Grub Street affair was the Press Association's shot of a beshorted Rupert's inner thigh as he drove home in a Range Rover. At this point the emperor was almost literally wearing no clothes.

As underlings scrambled to decide whether to sell News International, scrap the BSkyB bid or buy Rebekah an Acme hat-and-moustache disguise, Rupert was doing stretches with his trainer and pointing at the Serpentine. It wasn't convincing: he looked finished, doing little to destroy the many recent comparisons with Ozymandias. Look on my glutes, ye mighty! And despair...

Personal trainers are the one member of staff who has the power to say no to a Murdoch or a Blair or a Cameron and not face the wrath of their employer. CEOs and politicians are constantly criticised for surrounding themselves with "yes men". The hiring of a personal trainer is the one occasion when they deliberately hire a "no man" (or woman). It must be quite an odd thrill for a man who was used to (note past tense) Prime Ministers asking for measuring devices when he asked them to jump.

Personal trainers play a curiously paradoxical rule in modern political celebrity life – for actresses needing to stay dinky slim, lest the Daily Mail's website get them, they're a vital accessory. Ditto for skinny actors needing to beef up. To become the Prince of Persia, Jake Gyllenhaal employed British strength-and-conditioning coach Simon Waterson to turn him into the Iranian beefcake.

Waterson's website is an interesting (i.e. terrifying) site to visit. I quote: "THIS IS NOT FOR THE FAINT HEARTED BUT IF YOU NEED TO TURN ROUND YOUR HEALTH & FITNESS THEN SIGN UP IF YOU DARE, THIS IS ONLY FOR PEOPLE WHO NEED EXTREME DISCIPLINE BUT A GREAT WAY TO GET RID OF THE PAST & FOCUS ON THE FUTURE."

Less total detox and more Total Recall, but it's obvious that Hollywood stars and (especially) Westminster politicians naturally must possess an element of sadomasochism in their personalities to put themselves through fame/Prime Minister's Questions.

It doesn't take an ex-PR man politician to recognise the value in being seen being flogged by a tight-buttocked trainer. It says discipline, self-improvement and vitality. David Cameron opted for Matt Roberts, a personal trainer based in Mayfair famed for his work with girl group The Saturdays and comedian Michael McIntyre. I'm sure many would have liked to have seen Cameron put through his paces with Simon "EXTREME DISCIPLINE" Waterson rather than the man who keeps Frankie Sandford in a sub-10 dress size, but our Prime Minister did, at least, look at home in his gym gear.

Rupert Murdoch made a point of keeping his appointment with his personal trainer to spell out the fact that he was, indeed, In Control Of Things. The pictures had the opposite effect; one of Toto pulling back the curtain and an amplified voice from the heavens shouting: "Pay no attention to those liver spots behind the tinted windows!"

This was the first image of Murdoch in decades that showed him as a mortal. For so long he's been a living personification of The Man. Now, you almost felt sorry for him. Almost.

This is the point that Cameron, Blair, Clinton, Sarkozy et al fail to grasp when they bounce testosterone on to the pavements of their various capital cities. To run is to be human. It's as natural as sex or sleep and the carefully maintained façade of the politician cannot survive it. The face of a man or woman pushing themselves to run reveals a humanity that can't be hidden as it is in ministerial photoshoots. Don't believe me? Go and stand at mile 24 of a marathon route. The looks in the eyes of the runners are less a window in their souls than conservatories.

Parading around Hyde Park with a celebrity fitness trainer may be good PR, but it gives photographers the chance to see you completely unguarded (apart from the actual bodyguards, that is). In the state of nature conjured by the fierce exercise routine of a personal trainer, politicians unwillingly reveal more about themselves emotionally than their tiny shorts do physically.

Unsurprisingly, British politicians' vogue for running can be traced back across the Atlantic. Jimmy Carter was keen to test the potentially lethal combination of the world's most stressful job with a penchant for vigorous exercise. You can see him in the picture in the gallery above jogging with his trainer in Guadeloupe in 1979. That same year, Carter collapsed in the middle of a 6.2-mile race in Maryland. Running Times noted at the time that for the American public, the embattled Carter had "failed again". Ouch.

Other presidents followed: both Bushes were keen on a jog and Bill Clinton – a man with the fizz-bang combo of a bad heart and an Arkansan taste for fast food, no less – even had the south lawn of the White House paved with a track for running. This was after trips into Washington DC had caused traffic chaos. A man unworried by that is the current incumbent who, in 2009, jogged to a basketball game down New York's East 50th Street in Midtown Manhattan.

Away from politics, the hubris of the public run is personified by hotel magnate Rocco Forte – who invited journalists to watch him run during Granada's hostile takeover of his hotel chain. They caught him looking tired and exhausted at the end of his jog and it took his reputation years to recover. Presumably this is why one never saw Thatcher or Reagan chasing pavements around St James's Park.

Having a superfit personal trainer may allow some of their high-lung-capacity gloss to rub off on your macho image, but as powerful men from Rupert to Gordon will attest, it's just as likely to let the public see your human side. And that, after all, at least for us, might not be such a bad thing.