Outdoor Rides - Mountain Biking

[htims05]

I do interval training indoors on a spin bike, I do it for cardio fitness primarily. I’ve been mountain biking since I was a kid - more serious than a recreational rider, but less so now that I’m later in my adult life. That said training with a power meter has opened up a new world for me especially since I’ve coupled that with intervals.icu.

My question is - I’ve contemplated putting some power pedals on my mountain bike. Seems the internet is all over the place on if this is useful or not. From - it’s no good due to all the spikes and the coasting you do when mountain biking, to it’s only worth it if you’re trying to win races - none of which I’m doing. I’m doing XC biking, not downhill. On the east coast of the US so mostly flat, rooty single track - elevation change in a ride is probably 500 ft…maybe 1000’ depending on where I ride.

I’ve used Coach Jack plans and have substituted a “long ride” in the plan for a mountain bike trail ride - 10 miles, about an hour. Intervals.icu reports this always and over exceeding compliance to plan metric (which I believe is based on training load).

What’s the consensus here for someone who’s a recreational/sport mountain biker with a power meter in relation to interval training? Would I gain anything?

[Alex]

Cool another spin bike user. I use my spin bike more than smart trainer:)

I have to give my 2-cents. We are a power based platform so I should tell you need it and I think they are fun and you can spend lots of time looking at the data but I also feel they can disrupt that pure joy of cycling.

I mostly ride BMX and MTB right now and rarely track anything and I love it. Strava says I am not doing anything and I am ok with that (learned to accept it).

Unlike many others, I and my pro coach partner Andrea don’t feel you need to push yourself to the limits other than in races or when you feel like it. So he/I do not feel a power meter makes that much difference in performance unless it gets you to ride more or possibly ride with less intensity more often which is typically even harder on MTB.

So I would say it’s more about what is fun. I would actually like a PM on my MTB and can afford one right now but don’t want to spend the money there and really appreciate the purity of just riding. No tracking at all. FYI I mostly ride with my kids if it was more alone I might be more tempted to buy one.

Another reason might be increased accuracy of TSS estimates, if you are riding enough or hard enough to dig yourself in a hole stress wise and use a PMC chart to manage this stress now.

[htims05]

Right on. The data nerd in me wants to get one just for that fact. I do mostly ride on my own and find myself racing against myself but I don’t have a bar mounted computer or anything. I just compare based on the recording (using my watch).

I also use a PMC chart to manage my fatigue as I’ll get caught up in the numbers and trying to improve them only to not let myself recover…

[Alex]

In general I ride my CX bike on trails mostly and when it comes to technical/steep hills I can’t make it to the top I am pretty sure the power meter helped me dial in my power so I had reserves to get through the steepest parts but I am not sure on that

My guess is you would be so addicted to seeing and understanding your power you would be forced to buy a bike computer too. So this might be another reason not to get one

The numbers are surprising. Going over FTP on your MTB (any bike on hills) is incredibly easy so knowing your are depleting your reserves can help you back off.

[htims05]

So to day I put my assioma’s on my mountain bike and went and did a route that I take regularly. You get so much more info having power than you do if you just go ride. That said the load for the ride with the power pedals is almost half that of what it estimates without it. Now I don’t know if that’s because the last ride I was well fatigued compared to the ride with power - first ride after a week of vacation so maybe that plays into it as well - but my HR was pretty much the same.

Without Power:

With Power:

[MedTechCD]

The HR zones and Power zones are rarely matching. With some user specific config for HR zones, you can get something similar but given the fact that HR is always lagging, you will never get an exact match. What is unusual however in your case, is that HR load is way higher then Power load. MTB is by definition way more variable then road riding, and will in most cases give you a higher load when using power.
That is the reason why you should avoid using loads coming from different sources. Both HR based and Power based Load work quite well for the PMC chart on the condition you don’t mix them. It’s all relative and the trends will be very similar. The absolute values will differ.
The TRIMP loads seem to be a better match (~10%), so if you can’t use power based loads for all your activities, it might be better to use TRIMP or HR for all.
Intervals is giving you the choice what source you want to prioritize to calculate the load in the settings for the discipline.

[MedTechCD]

I forgot another nifty function in Intervals:
Have you tried using HRSS (normalized TRIMP) for HR load?
If you have enough workouts with both Power and HR data, Intervals builds an algorithm in the background that will be used to calculate a HR load that is way better matching the Power load.