So what is changing in your body as you get fitter that allows you to accomplish rides with greater kj expenditure? I know that as your FTP goes up your TSS stays relative to it but your kj from rides will increase.
As my FTP has increased over the year, I have maintained my weight about the same and my body fat is likely similar but what has changed that allows me to accomplish higher kj expenditures than earlier in the year? Without increasing muscle mass has the glycogen capacity of my muscles increased or is it all increased mitochondria?
As its winter base season, I am interested in achieving new highs in kj expenditure on the trainer. My current biggest trainer rides have been Dombai (1389kj) and Sandy Bay (1247kj). Looking at rides that really wore me down in the past they generally ranged from 1800kj to 3060kj (as estimated by Strava rather than power meter). Ranging from 3 hour group rides that were too hard for me and I got dropped to big 5 to 6 hour solo rides where I did my own pace but was spent by the time I got home.
My last road race of the year, I finished mid-pack with ~1650kj expended (Strava est) and felt good even though I didn’t have the repeatability to make the 2nd split that determined the front group. Where I found I was more overwhelmed were these higher kj efforts.
So wondering what is actually changing and then how best to focus on those changes in my training over the winter? I have been choosing longer but lower IF alternates for my workouts that have greater caloric expenditures, unsure if thats a wise decision or not. Have a goal to complete some >1500kj workouts on the trainer this winter like Chowchilla, Paatuut, etc.
I know the importance of nutrition and proper fuelling and while I’m probably not perfect, I am using high carb drink mixes and generally taking in carbs every 20-30 mins on these long or hard rides, workouts or races.
I mainly want to understand my physiological changes around caloric expenditure in a ride and how best to increase that capacity whether its to accomplish the 900kj an hour 2 hour rides or the 3000 kj 5 hour rides.
Assuming the answer is both but wondering if for example instead of Walker (6.3 level endurance 2h15m, 122 TSS, 0.74 IF, 1287kj) I have scheduled for this week, I should instead be doing Chowchilla (3h, 134 TSS, 0.67 IF, 1533kj).
I know that as my FTP increases so does my power targets and therefore my kj expenditure on rides so am uncertain if choosing longer workouts, with lower intensity but higher kj expenditure will negatively effect my AI FTP estimation. I feel that my stamina and my FTP are limiters (if I had a higher FTP I would not get dropped on the intense 3 hour group rides as they wouldn’t be too intense for me), if I had more stamina I could maintain an intensity for longer whether its on the 3 hour group rides or the 5 to 6 hour solo rides.