Personal FTP decay

Trying to come back into some kind of fitness after having our second child and I did a block of riding and training for a few months from the start of the year, complete with breakthroughs etc to determine my performance profile. Had a forced month off due to hectic work schedule, kids etc and have just started training again. After a 3hour ride at the weekend achieved a breakthrough which boosted my FTP from where it had decayed to, to its correct value by 15 watts (and actually to where I’d estimated it should have been anyway).

My question is, if the algorithm had decayed my values by 5-10% more than was actually true should I be on a slower decay? Is the ability for the decay to become personal per athlete looking at historic power profile gains and losses something that you guys are working on?

Hi Jack, You nailed it with your last comment. The fitness modeling when using Optimal Decay or No Decay track increases in TP/HIE/PP by monitoring your Low/High/Peak Training Loads. When time isn’t available to ride, the training loads drop (depending on their time constants - low training load decays slower than high/peak), and XERT then attempts to predict where your fitness signature should be, based on your historical data. Therefore, your breakthrough this weekend will help XERT learn how your individual fitness is affected by time off the bike more accurately moving forward. Hope that helps!

Thanks Scott. So over time and with more sessions I’d expect to see the decay more accurately reflect where I’d be after a short or longer break? Even though I’ve imported data going back 4 or more years?

Exactly. And it’s not necessarily the quantity of data that helps XERT, but the quality of the data. i.e. having breakthroughs fairly often and after long breaks off the bike helps fine-tune the fitness modeling/predictions. Cheers!