Metamorphosis

These days, I am never quite sure who I will meet when I run.

I don't mean the passers-by: late commuters turning into their driveways, shoppers alighting at bus-stops; dog-walkers and ramblers; allotment gardeners and parents in the swing-park.

No, I mean versions of me.

Often, when I set off, I have butterflies, a nervous tightening in my stomach and a prickle in the palms of my hands. As I close the garden gate and set my watch to record my time and distance, I wonder: which one of me is doing this run? Will I run it with ease and set a new time? Or will I have to talk myself through every mile? Does triumph await? Or misery?

Almost without fail, the first three miles of any run are hard work. While my mind is wiping itself clean of the day's tension and filing notable events away, my body is fighting me. Ugh, here we go again, it tells me. Are you kidding? After the day you've had? Why aren't you on the sofa? As I push on through those first minutes I am wholly and entirely engaged in psychological games with myself. "You can do this bit," I say, as the first hill arrives. "Hills, pfft, this is nothing. Remember the one on the heath last week. You've done this one hundreds of times now. "

But having done it before is no longer a measure of reassurance. It's become a challenge. There is so much at stake now. There is so much riding on this. The half-marathon is two weeks away. I have raised around £1,000 - a sum that makes me blink with wonder. People are expecting this of me. Grace expects this of me. Failure, as the Hollywood-style voiceover intones in my head every time I run, is not an option. To stop would be disaster. To slow down, a defeat. I am often nauseous with fear and the panicky thrill of second-guessing my abilities.

Last week, after I had finally finished the round of homework, dinner, bath and bed with my daughters, I opened the front door to run and realised it was entirely black outside. It perfectly encapsulated my mood. What I am engaged in now is not the stuff of balmy evenings and soft summer mornings. It has become something darker and more complex. There are struggles here. Something is being forged here. Even my appearance is changing. I'm not a middle-aged mum in tee-shirt and shorts: I'm a serious runner and now I have to dress as one in long tights, warm long-sleeved athletic tops and reflective jacket. I rarely run less than six miles and regularly run more than ten. I am starting to understand why the language of the running community has such an intense ring: we are warriors, athletes, philosophers. Long-distance running is both a mental and physical challenge and only the fittest survive. I am proud of what I am achieving here, and also scared by it. Each time I run further and faster I wonder at my achievement and frighten myself at the thought that I may not be able to better it.

On Saturday morning I had to run 12 miles: the furthest distance I have ever had to run. I set my alarm but awoke before it went off, feeling fretful and uneasy. I ate to fuel my body, gaining no pleasure from the cereal and banana that I struggled to swallow. I set off and for as long as I could manage, I avoided looking at my watch. I barely glanced at my surroundings or the path that I was following. I was entirely lost in a multilayered, schizophrenic, mental debate, telling myself I could do this while feigning a light-heartedness -- take it easy, stop worrying -- that made other me's shrug with annoyance even as others still tried to calm my jitters. At eight and a half miles I encountered a hill so steep I could almost have leaned forward to kiss the road before me. I willed myself to keep going, to somehow get one leg in front of the other again and again, to straighten up and relax my shoulders and suck in big lungfuls of air. A third of the way up it, blind panic set in. With nearly four miles still to do I simply couldn't see how I would complete this run. It was like turning over an exam paper to discover that none of the questions corresponded to those I had prepared for: I felt like simultaneously bursting into tears and being sick. Resorting to tiny, staggering granny-steps I shambled somehow to the crest and back onto the flat.

The next two and a bit miles were manageable, but I had started to feel pain in my right knee -- where I fell by accident a couple of weeks ago -- that gradually got worse and worse. By 11 miles I had shooting pains the entire length of my right leg, from groin to instep. Every step made me grit my teeth and close my eyes.

I have no idea how I completed that last mile. Putting the key into my front door was like coming round after a period of unconsciousness. I was shaking. Climbing the stairs to the bathroom took me ten minutes. I ran a bath and sat on the floor watching the bubbles form, aware of every tendon and joint in my body. I was still on the edge of tears as I struggled to undress. Somehow I hauled myself into the bath and sank below the lavender foam, feeling it pop in my ears and float through my hair as the blessed heat of the water soothed my muscles.

When I came up for air, I was grinning.