40km Cycle Time Trial

Saturday 25th July 2009

40km Time Trial - Squad Session

Power File Attached :-)

Today was a 40km cycle time trial and my key test set for the week. The time trial was part of a squad training session and set up on indoor cycle trainers. The indoor cycle trainer time trials are pretty brutal. The trainer effectively removes the effects of outdoor elements and is a test of pure strength, speed and power. You have no idea how fast anyone else is going so the focus is solely on you and the speedo.

I decided to time trial on my race bike so I needed to change my back wheel over so that I had power data available to me. The powermeter on my training wheel provides information on speed, power, cadence and heart rate so that I recieve constant feedback on effort and cycling efficiency. I had a clear idea in my own mind what I wanted to achieve today in terms of speed, time and power output. I was a little unsettled by a sore throat and cold that I had picked up midweek but I woke up feeling considerably better than I had in days.

After a 10 minute warm up we got the signal from Tony to start and a room full of cycle trainers whirred into action. During the warm up my legs felt sluggish but I put this down to my over sensitivity to the task ahead. However, as I attempted to gradually build my speed up to a target average of 42-44km/hr I couldn't get past 35-36km/hr. My power output and heart rate were off the scale and my legs didn't seem able to rise to the challenge.

I played around with my gearing for a few more kms attempting to find a gear that felt more comfortable but no gear seemed to relieve the load on my legs. I began to run through all the possible reasons for my poor performance wondering if I had under estimated the effect of my cold on my body or if the early drop in my body fat to race weight proportions so far out from Kona had resulted in a large loss of strength. I found it hard to believe that either of these factors could effect my performance so significantly but as the kms ticked by at a much slower than anticipated rate I became more and more engrossed in the reasons for my shortfall which must of course in my mind lay with myself. At the 13km mark I signalled to Tony that I was in trouble, my heart rate was not settling and my power output was far too high for the relatively low speed that I was pushing out.

Tony came across glanced at my speed and asked if I had actually started! He then noticed that my power output was off the scale and immediately moved to the rear of my bike. In one swift motion my speed leapt up to 44km/hr, my legs were spinning easily and my power settled within target range. Tony reappeared at the front of my bike and told me that it helped if my rear bake wasn't locked on the wheel......effectively for 13km of the time trial I had been cycling with my back brake on full lock. He then said 'that would mess with your head' and walked away! I immediately realised that when I had changed my rear wheel over I hadn't adjusted the brake to compensate for the deeper wheel rim.

The rest of the time trial progressed as planned with an average speed of 42km/hr. I was none too impressed with my own stupidity and although I came in at a respectable and solid 1hr flat I knew that I could have done much better and come in well under this. I felt that I made a good recovery given the energy sapping start but learnt a valuable lesson to look both outwards and inwards!

I've attached the power file for the time trial, the blue line represents my speed. After a little warm up (2 squares) you can see the time trial begin and the release of my brake in square 7 when the blue line jumps noticeably!!