I’m an amateur MTB racer, and I have been training seriously for more than 10 years, the last 5 years with a trainer with Power Meter and the last year with Power Meter pedals in my MTB and in the Hybrid I use for training. (I don’t do road).
intervals.icu is great for training with the trainer and to check my long rides with the hybrid bike, but is very frustrating to see how low is the load of a MTB ride vs road or trainer. I believe this is due to the spikes in power that although it is tough it results on a much lower normalized power.
On my 2-3 hour races where I ride as hard as I can and here in Florida where there are no downhills we pedal much most of the time, I get loads very low if I compare with the effort. I wonder if a bit different algorithm could be use to calculate MTB rides. Maybe using HR… I know is not as reliable than power and it changes with many factors, but if I ride 2 hours at my top Threshold HR, elevating it by 3 that should count a lot and I feel it does not.
Intervals.icu can already estimate load based on HR. Go to Settings>HR settings for more info.
The low load compared to RPE is the huge limitation of TSS calculation. Actually the more and more I think about TSS as a metric the more useless it sounds. All based around FTP, which tells you nothing other than the power you can sustain for an hour. Even at that the tests don’t even have you ride for an hour. Terrible load calculation once you go above Threshold. Gives no indication at all above how strong or weak ones aerobic base is. And all for what… To chase a CTL, a number, that has absolutely no correlation to what performance might be.
Anyway, rant over. I think TSS, CTL, FTP should go the way of the dinosaurs. No real place for them anymore imo. Maybe at a stretch it might allow you track progress during base training but that’s about it really
Hmm … spikes in power would normally result in higher TSS and hence load. If you click the load number it will tell you what the load would have been using HR. You can just enter that value manually if you think it better reflects your effort.
When you say spikes do you mean the normal power variations in MTB or is intervals telling you it has detected and trimmed spikes? If the latter, you may need to adjust your ftp / increase allowed power percentage over modelled power.
Unfortunately, even after that I don’t think any of the current ways of automatically calculating load will properly show the effort in, say an XC race. Normalised power uses a 30 second average, so if you go all out up a 20 second climb and then descend at 0 watts it looks like a slightly punchy effort rather than all out. Heart rate is capped at max heart rate so doesn’t show the full cost of anaerobic efforts.
RPE might be a more helpful metric, it depends what you want to use load for.
