[CFS]: Abnormally fast muscle fiber conduction in the membranes of motor units at a low-level static force load, Klaver-Krol et al, 2021

Absolutely. I've had the post-vaccination energy boost today, with the usual consequences for my leg muscles.

Normally the contractions seem weak and shaky, and the muscles feel unreliable; today, there's a smooth, strong contraction and a spring in my step. I can snap straight up to a standing position from the sofa, instead of shuffling my backside to the edge of the seat to make the most of momentum from rocking, and using my arms to help push myself up. My GP has described my general movement as resembling pseudo-parkinsonism, but it's vanished today.

Suspect it'll be back by tomorrow.

 

Exactly this.

Once out of PEM or infection or whatever my movement is smooth, coordinated and easily controlled. There's an advert for a pain relief product called Volterol that captures it perfectly - "the joy of movement". That describes it - easy & pain free.

However, the more I use those muscles and move into PEM, the more stiff, jerky, uncoordinated and painful my movement becomes.

After a week of bedrest or however long I need, as long as it's enough, I can stand up straight and move freely.

It's the opposite way 'round to conventional wisdom about deconditioning.

 

The interesting bit is why the early immune response to a vaccination or a head cold can do this so effectively, with no resting required (and, when I was still working, in spite of being perpetually in PEM).

 

Ah, now there we are opposites. My early response to a head cold will be a couple of bouts of sneezing, maybe the sniffles for a day and then I crash. It's the length of the crash related to what's gone on before that allows me distinguish between a minor bug & a crash after the event.

Once my body feels rested enough, could be a week or a month or even two, I'll be up and moving about with minimal pain and stiffness. Despite having lain in bed for all that time.

 

This is the bit before that; before I have any inkling that I've picked up a cold.

When I worked in an office and there was a bug going around, an unexpected improvement was usually the point at which knew I was in for it too! The sniffles and crash would follow on afterwards.

 

Ah ok.

So you get an improvement, then mild symptoms and so on.

I don't get the improvement. Just very mild brief symptoms and the crash.

 

Yep! Not always, but very often.

 

@Sean said, "My muscles are not weak, they are not usable." I like how concise this description is!

For twenty years my muscles continued to be firm and strong but I was actually pretty weak--unable to make use of that strength. But in recent years my increasing problems from old age as well as orthostatic hypotension, with a serious lack of oxygen and circulation--contribute significantly to a weak, deconditioned state.

Throughout my years with ME, I've had low to very low, stamina, but for a long time, like a lot of you (probably) younger people, I could still seem normally strong when sufficiently rested. Then I could walk as far as two miles, on a rare occasion, if the ground was mostly flat. Now however, I can only walk the distance of a city block, maybe two, though on better days ¼ mile. This winter I was inspired to walk a slow half mile exploring a frozen lake in the woods. I love seeing the beautiful patterns of animal tracks in the snow and the beauty of the light over such a landscape. But of course, the rest of the week I was in an empty altered state while my body restored itself. It was worth it to me as I am a passionate nature lover.

 

Cort has done a blog on this study but that's still the closest I've come to the actual paper, beyond the abstract. Has anyone been able to access the full paper yet?

https://www.healthrising.org/blog/2021/03/30/muscle-fibromyalgia-chronic-fatigue-syndrome/

 

Could try requesting it from the authors?
https://www.researchgate.net/public..._motor_units_at_a_low-level_static_force_load

 

Here are some correlates of increased conduction velocity:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1192232/?page=8
(decreased rise time, relaxation time and increased twitch torque)

I still don't have access to the aforementioned ME/CFS study...

 

Haven't read this one thoroughly yet, but attached a copy. Fascinating that the sEMG results in the CFS cohort were the opposite to those expected with disuse (sharp increase in conduction velocity with increasing force indicative of hyperactivated membrane function), and that there was a distinction to be drawn between the CFS and FM cohorts (low-threshold units in FM vs higher threshold units in CFS).

Fukuda criteria, though.

 

In general, conduction velocity is supposed to increase with higher activation threshold/higher force output and thus is associated with greater membrane excitability. However the difference isn't always appreciable at the force outputs used in the study (20% MVC). The FM patients were suitable controls in comparison to the CFS controls, since they had similar overall strength levels.

I previously mentioned the possibility of temperature affecting the results, but skin temperature was more or less the same between CFS patients and healthy controls.

The researchers did not utilise interpolated twitches, and we cannot assume that the spinal or motor cortex drive was the same between patients and controls, hence the effect can be due to central factors leading to altered motor unit recruitment. This can be caused by increased muscle afferent feedback! The researchers did not measure perceived effort (Borg scale), nor test at higher force outputs, which I suspect would have revealed a force vs effort slope relationship in patients compared to controls, as seen in other studies.

The other striking conclusion:

 

We are strange animals in that we are only as fit as we have to be. If we do exercise beyond the amount we are used to so that we go into using anaerobic respiration as the primary energy source the byproducts of that make mitochondria die off which is a signal to the cell to make more.

People who are sedentary are living well within their aerobic system's capability even if that capability is low but people with ME are actually forced to rely more on the emergency anaerobic system as our aerobic biochemistry is compromised.

In effect, we are the opposite of unfit. I seem to remember some research which showed we actually had more mitochondria rather than less.

Our muscles are desperately struggling to get us fit all the time. Workwell have found that is is almost impossible for us to increase our aerobic fitness.

 

It does looks interesting. If there's no explanation for it that's already understood, it needs replicating and then studying further with a carefully defined group of patients. If it's real, and unusual, it could be important.