I guess I was also interested in the guys who are still fast. Is it relative? Are you slow compared to when you were Elite or Expert? I'm still racing Sport here since it's open age wise because the 40-49 year olds appear to be ex Elite/Expert from their slightly down times. But are they freaks physiologically putting in tons of training and clean living?
Ok, so please forgive the rest, you don't have to read this or respond if it doesn't interest you. Sorry if you consider it self indulgent, but I guess this is a bit like when some others have shared about considering giving up mountain biking or riding altogether. I'll always ride trails I hope though.
Nothing scientific with the HR monitor, it's relatively recent and I last had one about 10 years ago, so I'm just comparing the max and average numbers. Old to new is roughly 190 v 180 max and 177 v 165, so amazingly by the ready reckoner numbers for a 30 and 40 year old. Races and rides seem to confirm these numbers repeatedly, and hitting the max early on trying to remain competitive forces me to reign the effort back in the middle of the race. Fairly consistent lap times seems to indicate I'm gauging my effort fairly well, but I'm placing anywhere in mid third of the pack between early teens and mid twenties.
Back when I was in my late 20s I was top 5 competitive in Sport for a couple of years. I could pick up my effort, maintain it, recover, and thus race strategically. It was my muscles and the lactate that imposed the performance barrier. Nothing special cat wise I realise of course, but now just turning a harder gear or standing up to climb seems to exact too high a price sending me straight into the red, so I spin which is also hard cardiovascularly. Meanwhile my head and muscles say come on we can do more.
The other variables of course are the weight and amount of riding. I used to be 72kg which still wasn't light for someone my height, but I used to be a sprinter and it seemed I had manage to train those fast twitch muscle fibres towards climbing. I smoked, even just before racing, and I commuted every weekday and raced once or twice a week mainly in XC or CX, but I rarely trained. Since then I've got as heavy as 92kg, and I've slowly got down to 86kg so far. I've had a couple of stints of not riding at all for a couple of years, and now I ride one 45km'ish trail ride per week and race maybe 4 times a year. At least I don't smoke anymore since I had a child though.
I'm not sure I could lose the weight really. I got down to 82kg last year eating cottage cheese all the time, but it's crept up again a bit since.