Took the Sufferfest 4DP Test - Comparing Results and Impressions

With the current Sufferfest offer (6 weeks for free), I decided to give it a try. The first step is taking the 4DP test, which has been discussed on this forum before.

The test yields five numbers and “categorizes” you as a rider. The five numbers are: 1) Neuromuscular Power (based on 5 second power); 2) Anaerobic Capacity (based on 1 minute power); 3) Maximum Aerobic Power (based on 5 minute power); 4) FTP (based on 20 minute power); and 5) Lactate Threshold (unclear what it is based on). The category it assigns you seems to be based on which of these numbers are higher and/or lower than the Sufferfest algorithm would predict based on FTP (that is just my guess). It labelled me a “Pursuiter,” as my 5 minute power seemed to be higher than expected. To me, what that really means is I have weaknesses at the others, and I should be looking to strengthen those. But I guess it’s all a matter of perspective.

I’m not near as versed in cycling numbers as others on here. But I have taken the TR ramp test and I have also gone into a lab to get VO2 Max and Lactate Threshold numbers.

My FTP numbers between the Sufferfest and TR differ by 1 watt. That’s it.

My Lactate Threshold numbers between the Sufferfest and the lab differ by 12 bpms (the Sufferfest did not give a corresponding wattage). That seems significant.

For those of you considering taking the test, I will say that it was quite difficult / exhausting, and that is even with getting off the bike for short periods twice during the test (as recommended). It is a 1 hour test. The 5 minute and 20 minute efforts left me feeling like I couldn’t go any more and had my HR at its “max.” As a less experienced rider, I did have some trouble pacing the 20 minute test. I had never tried to hold a max 20 minute effort before. The shorter efforts were peak efforts but did not completely exhaust me.

The test was also the first time I used “slope” or “level” mode on my trainer. With TR, I’ve always just ridden in Erg mode. For me, it was an interesting difference. It required a lot more engagement.

Finally, with TR, I generally have a TV show on while riding. The Sufferfest provides a video and music while you ride, as well as the traditional TR power view of the ride. It was a different experience. I can’t say whether it was better or worse, yet. But for those struggling to decide what music to listen to or what to watch, the Sufferfest solves that problem.

I’d be interested to hear other people’s results compared to TR and/or other tests. Also, I hope this “review” may help people thinking about checking out the Sufferfest.



Love the 4DP. It’s a great way to make sure that you’re getting a good variety of short duration tests in your testing protocols. I just redid mine after having done it first back in February. Went from Attacker to Climber (guess dropping four pounds made a difference). Same strengths and weaknesses: MAP is the weakness, 1 min is the strength.

I don’t use that many different suferfest workouts–just a couple that i like–but i use 4DP as my benchmark test and i think i’ll probably continue to do so.

You mention above that Sufferfest didn’t give you a corresponding wattage for your LTHR, but it does, no? Isn’t it the 20 min power result, i.e. your FTP? Or am i misunderstanding your point.

Did the 4DP couple of years ago.
Got my FTP pretty accurate (as accurate as FTP can be) vs FTP derived from TT race.

They got everything else dead wrong, from ‘rider type’ to ‘weakness’.

Glad I’ve never actually paid for their product.

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I used SF for a year before switching to TR, and used 4DP right after it came out. Outcome of that test for me was high anaerobic contribution, with high ability to repeat big efforts, but low corresponding FTP. For me that was spot on, and I still think that basing training targets off that test is a superior way to train. With TR, I always have to turn down threshold and below efforts, because I overtest on a ramp test (it’s repeatable, so it’s no big deal though), but targets in SF were always correct. That 4DP test is really daunting, and I’m not upset I never have to take it again.

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Haven’t used Sufferfest but I have WKO5 and do one or two max efforts every 2-4 weeks to “clean up” points on the curve.