# Let's talk about W' **URL:** \ **Category:** Training\ **Created:** [April 27, 2021, 10:11am UTC](https://wahoox.forum.wahoofitness.com/t/lets-talk-about-w/10005 "2021-04-27T10:11:26Z")\ **Posts on this page:** 1\ **Showing post:** 33
**Author:** ![Sir\_Brian\_M](https://sea2.discourse-cdn.com/flex020/user_avatar/wahoox.forum.wahoofitness.com/sir_brian_m/32/268_2.png) [@Sir\_Brian\_M](https://wahoox.forum.wahoofitness.com/u/Sir_Brian_M)\ **Post date:** [May 3, 2021, 12:16pm UTC](https://wahoox.forum.wahoofitness.com/t/lets-talk-about-w/10005/33 "2021-05-03T12:16:28Z")
I’m thinking W’ based off of 4DP values would be a tad lower than W’ based off of CP, assuming of course that you are doing maximal efforts at each duration within the last 90 days. NM and MAP should be close, but a fatigued 20 minute 4DP would not match CP20, and likely would not match CP60 (although it might be close). And the same could be said for AC != CP1min. I do think there are too many assumptions being made in many of these models for them to accurately determine future performance. There was a discussion on the forum about WKO which Sir Neal Henderson chimed in on, where he elaborated on the limitations of power duration modeling for this purpose. Bearing in mind that his job often entails this very need, predicting an athlete’s performance on an hour record attempt for example. > [@Full Frontal vs WKO5](https://wahoox.forum.wahoofitness.com/t/full-frontal-vs-wko5/7492): > > Let me preface this by saying that I think Full Frontal is the best FTP calculation method currently available outside of a formal testing laboratory, and I’ve read through the Xert thread on here as well, but I use WKO5 to track my performance and have found in the past that Full Frontal typically overestimates my FTP, whilst if I regularly test my Mean Maximal Power (MMP) curve in WKO5 on a 28 day cycle and aim for getting my Time To Exhaustion (TTE) above 40-45 mins, then the modelled FTP (mF… --- _[View the full topic](https://wahoox.forum.wahoofitness.com/t/lets-talk-about-w/10005)._