So I’ve been looking at efficiency factor recently since it got baked into intervals.icu (for the uninitiated it’s normalized power divided by HR). Like aerobic decoupling it appears to be a measure of aerobic fitness, if you see higher EF during a ride then you’re aerobically adapted. I’ve been looking at my pettit workouts the past 5 weeks and they’ve all been 1.4, while my sweet spot intervals tend to be around 1.6-1.7. Now if I’m understanding correctly, EF doesn’t necessarily give insight into potential changes in FTP, but just base fitness? If so, then it makes sense why my EF is so steady since I’ve maintained aerobic fitness, even if not top end stuff, all year.
Anyhow, based on search results, this isn’t something that’s been discussed around here, so maybe we can get a good chat going and others can dig into this for their own riding and their aerobic fitness assessments.