I love my back. I love the way it arches out, and then in, and then out again; I love its female narrowness; I even love the slight kink in my spine, like a treble clef. Sometimes, I confess, I stand close against a full-length mirror and twist my neck to try and see - and admire - the string of large round beads that make up my bare spine. If I were ever to be painted, I'd want a portrait from behind, naked from the waist up.
Perhaps part of my back's attraction is that it is the one bit of my body that isn't always being pestered to get into different, better shape. Dieting has no psychological sway in this area; no woman cuts down on calories to have slimmer shoulder blades. Orthopaedic surgery for cosmetic purposes would, of course, be crazy. A back is free from the double burden that breasts and bellies suffer under, all asked to take part in the reproductive process while looking as if they haven't so much as set eyes upon an infant.
Although sexy, a back has no obvious sexual function. It is also almost impossible to turn a back into an object of pornographic desire; it can only be wonderfully erotic. We're not even particularly interested in superstars' rear views. While we dissect every other area of their well-honed bodies, we never mention Madonna's, Kylie's or J-Lo's back. Although probably the most revealed bit of the female form, especially in summertime, the back is by far the least discussed. So backs are just allowed to be backs, liberated from the pressures put on nearly every other female part.
I also adore my back because it can be easily separated from those areas that are less than lovable. I picture my body rather like a jigsaw puzzle, each bit discrete, with some that are the perfect match to their neighbours and others that just don't seem to fit. I think most women tend to see themselves like this, in a series of segments. "I have a big bum but great breasts," would be a typical comment.
So when I'm told that our bodies just don't work like that, and that my very favourite bit is intimately twinned with my least likeable, it's distressing. According to personal trainer Kathryn Freeland of Absolute Fitness, you cannot work on a single part of your body without also working on its opposite. And the opposite of my back is my belly, which I do not adore. I have a very ambivalent attitude towards it; although it has dutifully carried three children, I struggle to consider it attractive and sexy.
Kathryn has given me a daily exercise to work my lovely back in order to redeem my recalcitrant tummy. It's called Superman, and I have to lie flat on the floor on my bad belly, lift up one arm and one leg, and stretch them out as straight as possible, holding that position. This strengthens my lower back, and so helps reduce my stomach. If I only worked on holding in my tummy muscles, then my beautiful back would suffer. For every muscle, there is a counter muscle that must be equally exercised.
But apart from this need to balance my belly, I thought my back was near perfect. So I was shocked when Holly Griffiths, the masseuse who works alongside Kathryn, told me it was in need of remedial treatment. She had me stand, naked from the waist up, with my back to her - just how I like to be. "It's incredible!" she cried. "Gosh - you're very different on one side to the other."
On the right, my shoulder was all built up; my left shoulder sloped down pathetically. It was the result, diagnosed Holly, of carrying a baby on my right hip, making me lopsided. She gave me a deep tissue massage; over time, this can, she said, together with paying attention to your posture, restore an irregular back. At her instruction I now have a yellow sticky label permanently attached to my computer screen - "Posture!"
Every time I glance up from my desk, this demand reminds me that a good back is not only about physical prowess, but moral purpose. ("Spineless!" would be a terrible insult.) A strong, straight spine gives poise, uprightness, dignity and bearing. By telling me I had a weak, lopsided back, Holly seemed to be casting aspersions, not only on the one bit of my body with which I was, until that moment, entirely happy, but on my moral integrity.
I know this wasn't intended. But Kathryn's and Holly's insistence on recognising opposites has shown that I can't pick and choose which part I want to love. However much I may wish it, my body is not a collection of different, disparate bits, but all of me.
· For further information visit www.absolutefitness.co.uk