Margin for error

Rather than the planned Fartlek, today saw me partake in a KM rep session. I decided on 5 reps beforehand, as my legs are still feeling the effects of Tuesday's steep descents at Mearley and a wise decision this proved to be.
Rather foolishly I had failed to check the battery on my Forerunner 205 and so I had a short panic attack. Fear not I thought as I rooted out my old Foreunner 301 which is a much larger unit as you can see on the picture, and also lacks the GPS quality of the 205. Still, it would measure my reps out, but how accuratley is debatable.
After my usual warm up of strides and bounds, by which time my 205 would have located its satellites, the 301 was still messing around deciding which part of the sky it was going to hook onto. I had had enough of waiting and so decided to set off with the Garmin showing a very weak connection.
I paid the price for this. As I look at my post session analysis graphs on Training Centre, the Forerunner had me down as doing over 5:30km/h for the first part of the rep. This is significant in the results:
1st KM: Feel nice and comfortable although my legs feel slightly jaded and there is a real headwind. The pace feels fast but sustainable. As the bleepers go, I am astounded to see 3:56 on the clock. With the benefit of hindsight, the weak connection at the start of the rep may have meant progress wasn't recorded properly and so the time was a lot slower than expected.
2nd KM: It's a Rep starting on a steep hill - not a nice sensation, particularly for the calves. Then down and flat, before an uphill finish which really tests my attributes, not to mention a brute of a headwind throughout. Not a bad effort though, 3:46.
3rd KM: I make a bold move to go onto the canal, and spend the first 10 seconds negotiating some steps which really slow me down. I hit the canal and really start to put the burners on, seeing a fellow runner coming the other way. PUSH PUSH PUSH! I continue to go for it and feel incredibly strong. What a Rep - 3:34 on an off road stretch, well strictly speaking anyway, although it is flat!
4th KM: Back onto the roads this time, with the cars of the A65 whistling past me. I focus on my own run and have little time to admire the River Aire. Soon I'm crossing the bridge and I'm back alongside it, running into a headwind and really starting to feel the burn now. I sprint as I hear the bleepers - 3:33!
5th KM: The final rep and it's all into a headwind. I desperatley keep checking the Garmin and before I know it I'm into the last 300. But then, what's this? A van pulls out and blocks my way through, so I have to wait for a couple of seconds for it. This spurs me on and I push for the imaginary line. There goes the watch, thank god - 3:40 including van stoppage time!
What a great session. I followed this off with a 2 miles warm down, taking the daily total to a pleasing 6 and the week to 17 so far. Tomorrow is the nice steady long run before a trip to the Galpharm for the first leg of the Playoff Semi Final. Come on Town!