Highly competitive riders will chisel down their weight in an attempt to improve w/kg, and this is certainly helpful. But it can also lead to miss-information, which has recently played a factor in some of my workouts. I just completed 2 rounds of VO2Max workouts, which are highly strenuous efforts in an attempt to maximally stress the aerobic systems, and stimulate adaptations to improve performance. During these workouts I was performing at about 4% less power than last year.. which was quite de-motivating to say the least. Backwards performance gains are not what I'm working for!
After digging, and reviewing last years data I discovered that my weight was about 6lbs more, so if I calculate power against weight, I am actually inside of a 1% difference. Whew, that's a relief! In addition, my LT intervals are improved by about 4% not factoring weight, meaning w/kg at LT has improved a whopping 8% (year over year, same time of year).. I like it!
But, what is better, raw power or w/kg when we are talking a 6lb body weight difference? Tough to say, but I feel faster at a lower weight, especially uphill. On the other hand I feel as though I don't quite have the "punch" and maybe even the "tempo power" that the raw power seemed to help with last year.. and this is important in MTB racing for accelerating, cresting short rises, stepping on the gas to pass, and grinding out long efforts.
In the end, you can't have it all. Its always a matter of compromise, and looking back seems to be the best way to determine which compromise seemed to work out best. For example, a few extra kg's may have helped me with this sprint.. but that extra weight may have made it more difficult to be there at the finish! (vs Ben Thompson, who recently placed 3rd at Cyclocross Nationals 30-34 age group, Dec 2009) :
