Using TSS or hrTSS depending on the ride type

Not really sure where this belongs, but here’s my question:

I have a power meter and HR monitor when I ride (stating the somewhat obvious :slight_smile: ). In TrainingPeaks it will use my power data and thus, TSS when I upload a ride (again obvious). My question is should hrTSS be used for endurance rides?

(Before you jump on me, I do know that TSS, CTL, etc are just metrics. I learned that the hard way)

If I do an interval workout where I have power targets, obviously TSS is the best metric to use. However if I do an endurance ride - think Z1 in the polarized model - does it make more sense to us hrTSS?

My thought process is that since those rides are focused on HR, that metric may be more applicable. However, I’ve also always thought that power was the true measure of what you’re doing on the bike. And since it’s not apples to apples, should I just always use TSS. Part of it may be ego as well since in those Z1 rides, my hrTSS is usually higher than the regular TSS.

I’m curious the hear your thoughts? I know this probably more of an opinion than one based on real science.

Others may have some opinions here but I believe that hrTSS is only calculated when there is NOT enough data to calculate TSS (say NO powermeter or a file missing a lot of power).

So if you are riding with a powermeter, I think it will always calculate using TSS.

If you use a bike without a powermeter, it would calculate the hrTSS.

I would always run the powermeter and do workouts by power when you see fit, heart rate when you see fit, and look at the trends over time of power to heart rate ratio to see the power improving at the same heartrate, or heart rate dropping at the same power.

From a quick google on TrainingPeaks.

hrTSS is used as the default in TrainingPeaks when there is not enough data to calculate TSS, rTSS (Run Training Stress Score) or sTSS (Swim Training Stress Score). It can be accurate, depending on the effort, but doesn’t do as good of a job at incorporating intensity and duration into the equation.

Agree with @steveneal completely. So I use power on my road bike and singlespeed MTB, and HR only on my geared MTB. I don’t change anything - when it’s a ride on the geared MTB, hrTSS is used. On the other two bikes, TSS is the metric. Unless you’re following CTL religiously rather than looking at how you’re building your overload, it’s not going to make a difference in my experience. Ego and CTL definitely go together, so I can understand where you’re coming from there. You can have great performance at relatively low CTL values, so I all but ignore that metric, other than looking at it in terms of how that load is achieved.

1 Like

Thanks @steveneal and @ryan - those answers make total sense.

I have come a long way from TSS and CTL are the most important thing ever :man_facepalming: However, I think this was the last little trick my mind could come up with to see higher numbers.

I like the idea of focusing on the purpose of the ride/session and not always attaching a number to it. It’s still a transition for me, but it really does make the most sense.


I don’t have a PM on any of my MTBs, and I prefer to set a goal for the ride that would be similar to doing it on the road bike or IDT. So I might tell the group, that I’m riding with, that I want to do 3x 8-min efforts on the ride. I know what it feels like, so will ride at that effort as and when I get to the specific waypoints on the route. It could be full gas effort on a flat district road (untarred), or an 8-min climb. If know the route I can plan accordingly; most times it’s the same route with a few deviations.

The hrTSS might not line up with the equivalent TSS if I had power, but my body doesn’t know if I’ve logged the activity or not, but it does know when I’ve done the workout.


Oh…the Singlespeed data isn’t it amazing and quite often the opposite of what most people think it would be.