Aug 13, 2026 · 1 hr 22 min · 17 segments
Physiologist Mac Cassin and the team at Wahoo are developing ways for athletes to better understand their strengths, weaknesses, and biggest areas for improvement with their Dimensional Training Load…
Mac CassinGuest
Trevor ConnorHost
Ian BoswellGuest
Chris CaseHostAlia ShafeeGuest
So we're talking about your 4DP and your DTL, which we will define, but you are trying to do something at Wahoo where you are moving beyond what cyclists are used to of everything is FTP based, that's your one key number, and really trying to give a more robust view of the cyclist as an athlete.
And I'm just gonna say, while it sounds all really cool and sophisticated, when this first came out, I did your 4DP test, and it's really painful.
That said, I think I did it for the first time in, like, 2010, and I'm still doing the test 'cause it is a valuable test that you get some really good numbers out of it.
It, it helps you kinda contextualize all the different areas of your fitness and how they're changing over a season, how they're changing year to year.
And if we're being honest, it's just a good workout, and most people who wanna get fitter are okay doing a hard workout.
So as long as you view it as just go out and give it your best, there's no right or wrong way to do it.
Something I find, so I'm talking as a coach right now, really interesting about the test.
So we've talked about it before on the show, and do wanna give a, a quick call-out to Neal Henderson because he really designed this, and I know he was part of the origins of, of 4DP.
He sent us out a long time ago to, to give this a try, and it's within an hour, you do several five-second sprints.
Then you do a five-minute effort, then a 20-minute effort, then a one-minute effort, all within 60 minutes.
And what I find fascinating about this as I give it to athletes is you can learn a lot about what type of rider they are by which of those four efforts they say is the most miserable.
So we're talking about your 4DP and your DTL, which we will define, but you are trying to do something at Wahoo where you are moving beyond what cyclists are used to of everything is FTP based, that's your one key number, and really trying to give a more robust view of the cyclist as an athlete.
And I'm just gonna say, while it sounds all really cool and sophisticated, when this first came out, I did your 4DP test, and it's really painful.
That said, I think I did it for the first time in, like, 2010, and I'm still doing the test 'cause it is a valuable test that you get some really good numbers out of it.
It, it helps you kinda contextualize all the different areas of your fitness and how they're changing over a season, how they're changing year to year.
And if we're being honest, it's just a good workout, and most people who wanna get fitter are okay doing a hard workout.
So as long as you view it as just go out and give it your best, there's no right or wrong way to do it.
Something I find, so I'm talking as a coach right now, really interesting about the test.
So we've talked about it before on the show, and do wanna give a, a quick call-out to Neal Henderson because he really designed this, and I know he was part of the origins of, of 4DP.
He sent us out a long time ago to, to give this a try, and it's within an hour, you do several five-second sprints.
Then you do a five-minute effort, then a 20-minute effort, then a one-minute effort, all within 60 minutes.
And what I find fascinating about this as I give it to athletes is you can learn a lot about what type of rider they are by which of those four efforts they say is the most miserable.
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