For the purposes of this column I have been rigorously assessed and passed as fit, so where do I go from here? Back to bed? Fitness coach Jamie Baird says I need to be "stronger and bigger"; realistic goals to which I might only add "able to leap over tall buildings". And impervious to pain, if possible. I look around the gym though, and I see the familiar purgatorial array of treadmills and televisions. If I'm going to carry on training, I am going to have to seek out new exercises, new equipment and new shoes.
The first stop on my journey to superheroism is a modest little gym called Sport Dimensions. Apparently professional athletes make pilgrimages here to endure Frappier Acceleration Sports Training (Fast), said to improve performance and speed recovery from injury. Signed, framed shirts decorate the walls of the tunnel-shaped room. "We've trained everyone," says coach Mike Freyer, "from someone who was crushed by a lorry, to a rugby player who was in a coma."
It's hard to describe Fast without traducing it horribly, but let's try: it's basically about running on a very fast, very steep treadmill. Backwards. With a harness on, in case you can't handle the 28mph pace and fall off. "Walking backwards is about three times harder than walking forwards," says Freyer, fetching a harness from the rack. It also relieves pressure on the joints, enabling injured athletes to stay fit. Even the lame can't rest anymore.
Walking backwards on a treadmill made me feel 15 again: ungainly, awkward and graceless, and this was before Freyer told me I had to let go of the railing. Though only for 18-second bursts, this proved more than sufficient to start every leg muscle burning. After a brief rest you do it again, and repeat until knackered. Should you get good at it, they have special rubber bands to attach to your knees. On the adjacent wall there hangs an inspirational quotation from Lance Armstrong: "Pain Only Lasts a Moment, Quitting Lasts a Lifetime." I think about that back in my car while I'm trying to summon the strength to depress the clutch pedal.
· Next week: Lucy Mangan goes for her first ever jog