@themagicspanner it’s prudent to take those power duration curves with a grain of salt. The other adjunct is that your power duration curve may suggest that you can keep 90% of your ftp for two hours and you may be able to do so, but that is definitely not the case for everyone. The curve is sigmoidal and will be impacted by a lot of variables. Simply having a higher 5 second power can decrease the curve on the far end and vice versa. It also depends on what ones training has consisted of and what their own physiology is like. Similar to the same reasons that someone may not be able to hold their ftp for an hour.