In sessions early in the month I could maintain an average speed of 20 mph for 1 hour at an average heart rate of 146 beats per minute. That translates to an estimated 250 Watts of continuous power. By itself this data is not particularly meaningful, but it does provide a baseline of effectiveness of my training efforts. With the exception of adding Yoga to my weekly regimen and an outdoor ride or two, I have not changed much.
This morning, my body was trying to tell me something as I spun. I was having trouble even maintaining 19.5 mph and my heart rate was about 144 on average at that speed. This is on the same bike, with the same gearing, on the same trainer in the same basement that I have been riding all winter, yet my power output was only 244.8 Watts on average. This obviously translated to a lower average speed for the session. I can't tell exactly what my body was saying, but it got my attention. This is why it is important to have some objective measure (like heart rate) to get a glimpse of what is happening in your body.
- Was it nutrition - sitting on the couch eating BBQ meatballs and Goldfish during the Super Bowl?
- Emotional - being subjected to the deplorable performance of the Black Eyed Peas during the half-time show?
- Over training - not likely.
- Result of a lot of climbing on ride Saturday?
It could have been any or all of the above - the important thing is to pay attention and look for trends. If it is an anomaly then you should see speed go back up again without a corresponding increase in heart rate. If it continues, then start looking at different factors to see if you can isolate variables. Take 2 or 3 days off and try the workout again - if it is better then you may not be devoting enough time to rest and recovery. This observation will help you train better, by finding the factors that either hinder or boost your performance.