Reporter Josh Pettitt prepares to run the Highgate Fun Run for the care of the elderly at the Whittington Hospital.

Preparation for a leisurely 5km charity run round Hampstead Heath should be a stroll in the park, or so I thought.

To check if I would last the distance, the Whittington Hospital saw fit to put me through my paces at the Virgin Active gym in Holloway Road in preparation for the Highgate Fun Run next Sunday (September 25).

Personal trainer Bruno De Freitas was there is watch me squirm under his forceful guidance, but it was all for a good cause.

Money raised from the run will help buy new equipment and furniture for the elderly Day Hospital at the Whittington, which is due to move from the inaccesible sixth floor and be reopened on the ground floor in early 2012.

The centre currently treats 1,500 older people who suffer dementia, Alzheimers, strokes, injuries from falls, osteoporosis, diabetes and many other conditions.

To prepare for the run I flung kettle bells over my head, hung from a bar with my legs in stirrups and sat on a plate which sent extreme vibrations through my body during three sessions – all for a 5km run.

Evidently running and training has become far more technical than slinging on a pair of inappropriately short shorts and pounding the streets until a park bench presents itself.

It was up on the treadmill and up on the incline – apparently running without an incline is plain cheating. My left knee poked out and felt awkward, but it was not enough for Bruno to reconsider increasing the pace, and three very long kilometres later the job was done.

Time to hit the pub? Apparently not.

Running, these days, is also about core stability and “running from the glutes”. This is particularly relevant to the modern day officer worker who spends 9am to 5pm glued to a screen with these all-important muscles melting into a chair.

So on to the TRX suspension trainer - and it is as intimidating as it sounds.

Navy Seals have started using this practical equipment, hanging off the side of tanks in the desert for resistance training. Needless to say, I didn’t fare well.

On the point of collapse and continuing the military theme Bruno marches me up and down the gym carrying kettle bells.

To finish, Bruno laid me out on a power plate and turned the vibrations to maximum, making me speak like a Dalek and giving me a juddering headache.

The movement pumps blood to the area under pressure and is supposed to relieve any stiffness.

Back in the gym a few days later, the technology has not quite worked its magic and I’m as stiff as a board. On Sunday I think I’ll resort to the tried and tested tiny shorts and inviting park benches.

For more information and to register for the Highgate Fun Run visit www.virginactive.co.uk/funrun

To donate to improve treatment for the elderly at the hospital go to www.justgiving.com/HamandHigh