The impact of Torque on fatigue and the use of TSS

Interested to hear thoughts on quantifying the additional recovery load required when considering training stimulus such as over geared work or seated hard start accelerations and the wider impact in general of using a lower cadence and more torque on the overall muscular stress of a workout.

I’ve not seen much discussion on this but feel it’s often overlooked when considering stress, work and recovery and perhaps has a much greater impact than other factors.

An example - commuter cyclist riding a single speed bike 20 miles a day 3 times a week using 48 x 16 gearing switches to 48 x 17 or 48 x 18 maintaining the same power but at a higher cadence. Muscular stress is greatly reduced and their capacity for other work increases however TSS clearly won’t reflect this.

Athletes with more fast twitch muscle fiber require more time to recover from endurance training. Slow cadence recruits larger motor units in the working muscles and then more fast twitch fibers get involved. Longer recovery would be logical.
Using high cadence during VO2max workouts could reduce recovery time with that logic.

https://journals.physiology.org/doi/full/10.1152/japplphysiol.00636.2019

Sorry, but that’s a myth. Regardless of whether you rely on EMG, MMG, or classical PAS staining, there is no evidence that motor unit recruitment varies significantly with cadence at a fixed power.

Have you actually tried this sort of thing?

I have, as it used to be standard practice for winter training. I never really noticed any difference when stepping through 42 x 18 to 42 x 17 to 42 x 16 over a 3 month period.

In any case, I would think the fact that TSS doesn’t account for the much greater muscular stress of, e.g., weight training would be a much bigger deal. By comparison, even standing starts don’t put as much stress on your legs.

No need to apologise:)
Was it studied among cyclist with varying ST/FT ratios?
I have heard, that ST/FT ratio might be contributing to each cyclists optimal cadence and more FT dominant cyclists benefiting high rpm and so avoiding using those oxygen hungry FT fibers while ST dominant cyclists being more flexible with cadence.
For me grinding with 75rpm is way harder than riding same watts in 95-100rpm. Is there some physiological explanation for this?

Didn’t have proper time to read thoroughly this paper, but cadence vs EMG activation was affected with 60rpm vs 90rpm.

https://www.researchgate.net/publication/38026032_The_efficiency_of_pedaling_and_the_muscular_recruitment_are_improved_with_increase_of_the_cadence_in_cyclists_and_non-cyclists

Yes - 48 x 16 vs 48 x 17 has a noticeable impact on my overall “freshness” and ability to cope with additional training volume and intensity. The feeling is very similar to when adding weight training into the mix. Grinding vs spinning is talked about fairly often in regard to single workouts/rides but I think the cumulative impact can be large.

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Sorry, missed this previously.

Greater total EMG activity does not necessarily mean greater MU recruitment. It could result from an increase in rate coding. The only way to differentiate the two is to quantify the distribution of firing frequencies via spectral analysis, and see if it changes with cadence. Studies that have done this have found no effect.

Interesting discussion. I swing a bit the other way. If I start a VO2 max effort at say 100 rpm, I can only sustain that cadence for maybe 2 mins before my lungs are exploding, but I can then back off the cadence right down to 75-80 rpm and continue grinding out the same power for at least as long again. Then I may find my legs are burning but my breathing has recovered just enough to revert back to a high cadence again for my last effort before finally dying!

With longer sustained FTP efforts I find that my optimum cadence is around 80 rpm or even slightly under. If I go above 85 rpm I may start having breathing issues at that power level after about 10 mins as my HR creeps up, but dropping back into the 75-80 range brings my HR and breathing back under control. I certainly can’t hold FTP efforts for very long above 90 rpm. But I do like spinning at 90-95 rpm at low power levels and sprint at around 105-110 rpm.

I have no clue what effect all this has on TSS though! Although I usually feel more subjectively tired after a high cadence workout than a grind-fest of similar TSS.

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For VO2max work I have used same strategy, but heard, that for training adaptations it would be more beneficial to keep cadence high. Lower cadence would shift strain to anaerobic energy production. N=1 observation; lower cadence results reduction in hr and breathing rate.
For me best TTE it is a balancing act between burn in legs and burn in lungs with varying cadence

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I suspect you are right about the high cadence adaptation. I just hold a high cadence until I can’t! It’s something of a weakness for me, yet my VO2 max is fairly high for my age group.

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