# 4dp v ftp

I’m taking the occassional workout on calendar outdoors when feasible… on the map 6×2 I noticed in the outdoors instructions are 150% FTP for 2 minutes. Why wouldn’t we use a %age of our MAP value instead as the whole concept behind 4DP is to relegate ftp-specific training to the bin, no?

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Excellent question! Following.

I reckon they’ve done it because people might be using the likes of Training Peaks to create a workout file for their head unit and that’s just easier to do using percentage of FTP as there is no option to input directly as a MAP percentage.

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True, but then you should still be able to enter the specific percentage of FTP that relates to your unique MAP so if not 150% then 175% or whatever the case may be based on your 4DP

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Yes, I would think they would at least do an either/or. Either x%MAP or y%FTP.

But that would require a little bit more work in converting from MAP % to FTP % on an individual basis so you could input it into your head unit. I think they just wanted to keep it super simple for outdoors.

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The problem is that the y value would be different for everyone. So they could give you just the x value for % MAP and let you work out your own y value (I’ve done that when porting SUF no-vid workouts into Zwift) and it would be more accurate. But it’s definitely more complicated for the more mathematically challenged.

The outdoor plans used to use MAP for targets i.e. saying 90% of MAP. You just need to work out what that was and use a % of FTP that got close to it when inputting on Training Peaks.

@Peteski and Sir @emacdoug while granted, it would be a little more complicated, one of the future goals of SYSTM is to be able to export these workouts to head units directly. Given that the plans are all based on our individual 4DP, I think the outdoor rides in those plans should take those numbers into consideration.

So, either a unique multiplier for FTP based on the 4DP or a range of watts that represents that.

Tbh, I’m not at all invested in this as I can’t bring myself to actually do formal training outdoors. I realize that there are loads of people that do though and I think if exporting to a head unit is in the cards for SYSTM it just makes sense that the 4DP calculations are used in those workouts.

I’m personally more interested in seeing the reverse. Ie bringing our outdoor rides into SYSTM (and maybe making adjustments to our workouts going forward as a result of that aka Adaptive Training).

I still really wanna hear what the wahoo scientists have to say on the OP.

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Most head units can’t cope with 4DP profiles. They can only deal in FTP %. Which could be a clue as to why these are now expressed in terms of FTP

So, basically, it could still be expressed as a percent of FTP, but for each user, it would need to look at each user’s 4DP to compare their MAP and FTP values to create a custom FTP% for each workout that would then get displayed and exported. It definitely sounds doable. Just would need more work than putting in a blanket 150% value.

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That’s right. Given that it’s an outdoor session without ERG, it probably isn’t worth the extra hassle of customising it. In reality you are going pretty much flat out on those intervals with RPE of 9

I’d be almost willing to bet that the wahoo scientists are working on making sure the outdoor workouts are based on folks 4DP. Actually, I’d be surprised if they’re not.

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I think the issue for the scientists and the Devs is what to focus on first.

Do they spend time on interim developments to fulfill a hallway house solution, or focus on an end goal of exportable workouts, that ideally are also trailered to an individual’s FTP/4dp.

A wider question for the scientists, in the fluid world of the great outdoors, how much control/focus does the evidence say can delivered around AC, NM and to a lesser extent MAP type segments where the rider is trying to achieve those specific numbers at specific times in a workout, whilst coping with all the additional confounders of traffic, junctions, lights etc.

According to DC Rainmaker 4DP is coming to head-units but probably only Wahoo devices.
As @emacdoug said this should be possible with a individual %FTP value based on the 4DP MAP, NM and AC value relative to the FTP. So it should be possible for other head-units too.

Note that all of these workouts are designed to be done indoors at this time. Wahoo says that they’re hoping to have outdoor variants by the end of the year, but will not likely have the actual connectivity to head units until next spring. Though, they did say that connectivity won’t be limited to just Wahoo head units, but they aim to have it device agnostic. However, they noted that likely only Wahoo head units will support 4DP power profiles, which may limit exactly how those workouts enumerate on other hardware platforms.
Hands-On With Wahoo’s New SYSTM Training Platform | DC Rainmaker

Everything is possible, but that doesn’t mean it will happen. It makes sense that Wahoo head units will likely support 4DP profiles, but others probably won’t. I think DCR’s comment sums it up well and for me explains why the above outdoor workout is quoted in terms of FTP. Even if Wahoo head units can support 4DP, it’s pretty unlikely they actually will from the very start. My guess is that initially all the outdoor sessions will be exported in %FTP and Wahoo head units might later get a full 4DP variant. Will it matter? I don’t really think so, as all those higher MAP and NM power targets will be effectively maximal efforts over their respective intervals. It’s not like you are riding on a trainer with ERG mode. Power will not be super consistent outdoors. For this reason most head units specify a range of power rather than a fixed target for outdoor training.

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