I've been riding a lot with a cycle specific heart rate monitor that gives an estimation of your energy usage while exercising. I've been using it for this year and a different one the year before. I've noticed that when I ride regularly the energy used for trips seems to drop even though the effort I'm putting in 'feels' the same, whilst the average speed increases. I guess this is due to your muscles becoming more efficient as you get fitter.
When I look around the internet there seems to be many estimated kcal/hr that will be burned during riding, and most of these seem lower than what I use. I assume this is because they are for more leisurely riders, rather than my style which is close to as fast as I can do any ride I take, keeping a little back just in case.
The figure that the heart rate monitor displays is the amount of energy burnt during exercise, when divided by time this gives a power usage. The output power to the road is going to be less. The percentage of the power used that is output to the road would be the riders efficiency. On my hunts on the internet the commonly sited figure is 25% efficiency. Is this figure for a very fit person, some one who can commute 100 miles / week without too much trouble, a leisure cyclist getting out only on the weekends, or average Joe?
I just did an hour session on my turbo trainer and the monitor said I burnt 6212kJ, which works through as 1.6kW power usage and 408W average power output. This seems a little high to me, are there any ways to gauge the efficiency more accurately without having to shell out £200+ on a power meter setup?
The monitor has my age, weight, and max heart rate set for me. I found my max heart rate by holding a good speed up a steep hill for as long as I could before I felt like I had to stop.