The quest for a sub 3.45 hr marathon and my weird leg: Neural tension; chronic pain, or bad memories?

My left leg is officially weird….

It ran a sub 1.45 hr half marathon 3 weeks ago, grumbling a little after and jabbing me a few times during, but actually it has felt ‘mostly’ better since.

I say mostly because after my trip to Newquay and the irritating Flybe flight home, it grumbled on an easy 7 miler…..

But then I ran 11 miles of hilly offroad, rested for 30 hours and did mile repeats at 7.30 min mile, and it was FINE. Not a squeak out of it. Even though I haven’t done any running at below an 8 min mile for 8 months!

So, what’s going on?

I think the upshot is, no one knows.

But as a biology teacher nerd, I have my theories…..

Here they are….

Neural tension (now called neurodynamics)

There are lots of physiotherapy sites talking about this phenomenon as a cause of unexplained, persistent pain.

The second physio I saw thought that I had an element of so-called ‘neural tension’ going on after my ‘Hamstring pull’ refused to stop niggling for 6 months.

It makes sense for me…..

The theory goes that when you compress a nerve, you stop blood flow and cause nerve irritability.

Nerve compression can result through all sorts of things, but mine seems to have started with increasing cycling distance for triathlon too quickly, immediately after my last marathon and, oh yeah – doing burpees in Tae Kwon Do straight after a 17 mile hilly bike ride!

I am now 18 months older, wrinklier, and wiser!

I accept cannot do everything at once.

So marathons it is (for now) HOPEFULLY…

The problem with my hamstring issue is, it went away when I stopped cycling, then recurred when I spent 14 hours a day editing my first novel in a bad chair whilst increasing running speed and distance too quickly….(there’s a theme emerging here). Presumably this is because I compressed the nerve by sitting….numerous physio/chiropracters/osteopaths agree. It’s been an expensive injury. Who said running was free?

The theory goes, that compression of the nerve combined with the kind of inflammation you get from overtraining (guilty) can also cause your nerves to act up, causing pain even in the absence of damage.

Now, I already had damage, so probably scar tissue came into it too. Some of the theories also suggest that scar tissue can impede nerve movement, hence the tension…..

Conclusive studies though?

Very few.

I found one reference on an obscure physiotherapy site for a study that reported that of 14 rugby players with hamstring pain, most actually had neural tension rather than a hamstring injury.

That is a SMALL sample..

And you can’t see neural tension.

But as a theory it could explain why my hamstring ‘stiffness’ has been so recalcitrant.

It’s just that it’s all based on ANECDOTAL evidence, and as an ex-scientist who slogged their guts out collecting data, I don’t like that!

What about treating neural tension?

According to a review of the evidence that neurodynamic interventions like nerve glides and slides have any impact on recovery from persistent pain, there is no conclusive evidence that these things work!

The main reason, is that the studies all use small samples, different groups of people, and different therapies.

So, from my perspective, until research groups do the same thing to a large sample of middle-aged recreational runners (about 100,000 ideally) with hamstring injuries, we are not going to have significant evidence to support any of the suggested treatments. They made my symptoms worse, actually, so I stopped them.


The review is on ncbi here

Chronic pain: thanks for the memory

Openstax textbook image shared in Wikipedia commons.

I don’t know if I would go so far as to say that I have chronic pain, but the studies described in this review were just too intriguing not to put in here. And as a biology nerd it got me thinking about whether I have an element of this going on…..that makes sense too.

It seems that injury can sometimes lead to production of more ‘pain’ receptors than is usual in the dorsal root of your spine! I put ‘pain’ in inverted commas because actually the receptors are actually for neurotransmitters, but the neurotransmitters allow an impulse to be sent to the brain from the spine, telling it there is pain. More receptors mean more neurotransmitters bind to receptors, and more neurotransmitter binding means the brain is being told it’s in pain more often. It thinks its serious when actually it isn’t….

Apparently, it is normal to produce more ‘pain’ receptors immediately post-injury to help protect the area from further damage. At this point, pain sensors are more responsive to slight triggers. After all, if a slight tweak ‘hurts’ more than normal, you’re less likely to carry on doing something that really could do more damage because that would be excrutiating….

It seems, though, that people with chronic pain may have more ‘pain’ receptors in the dorsal root for longer than is normal. And that’s why they feel lasting pain. You can read the review here

It appears that this is really a very similar mechanism to memory storage, and so there is a theory now that pain has a memory. Memories seem to be reinforced when retrieved by the synthesis of more receptors. The more receptors you have by my limited understanding, the stronger the memory is.

The upshot? It’s possible that to some extent (and I don’t believe we have the full picture), chronic pain could be a memory.

Does that make it a good idea to ignore pain?

I doubt it.

Everybody is different, but after a full year out of doing any races, I think I will play it safe and listen to my body carefully this time. Memory or not, better to be safe than sorry.

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