Tissue Strength and running tolerance: do we need to change and expand our thinking

Why this blog: This is a bit of thought experiment. Bear with me.

I hate running

Not sure why I do it. I do prefer talking about though

ASSUMPTIONS ABOUT PAIN, INJURY AND RUN TRAINING

  1. Tissue injury/failure is considered to be a cause of running related injuries and pain. It is assumed that building tissue strength will decrease our injury risk. Hence, we say things like injuries occur when Load exceeds Capacity. Yes, there are issues with the term Capacity but that’s another blog

  2. Some research suggests that Bone and Connective Tissue (tendons, fascia, ligaments, cartilage) do respond positively (e.g get stronger and more resilient) to mechanical loading BUT after a brief period of mechanical loading (10 minutes) the tissue becomes “deaf” to the stress. Meaning, more load does not lead to greater structural adaptation and tissue strength (bone paper here). But after a brief period of time (4-6 hours) the tissue is ready to respond again.

  3. Specific joint exercises which load a bone, tendon or joint are recommended to “build up” that tissue. It’s assumed that this will cause the tissue to become structurally stronger and will be less likely to get injured.

  4. It is a foundation of good running programming to slowly build up your running volume and intensity to avoid injury. It is assumed that slowly building up will cause tissues to get stronger and we will be less likely to have an injury. (i.e tissue failure)


THE PROBLEM AND THOUGHT EXPERIMENT

Considering that tissues fail to respond after short periods of loading do you think that…

…An individual who has run for 3 years at 5x/week for 20 minutes each run will have the same tissue resiliency strength as the individual who slowly built to running (over 3 years) 5x/week for 60-90 minutes per run?

If we consider assumption #2 then in terms of tissue resiliency and strength these individuals would have comparable tissue strength. Because, if the assumption is correct, that extra “time on the feet” in the person running a lot would not have catalyzed any ADDITIONAL positive tissue/structural adaptations. Yes, I know there are other adaptations in the other systems of the body. But, structure wise, there should not be a difference.

Related, if the 2nd assumption is true it means someone who has been running regularly (5x/week at 20 minutes) could just double or triple their running volume over the course of a week and maintain that. They would have the structural resiliency of the person running 5x/week for 60-90 minutes. There would be no need to slowly increase their tolerance to running because a slow build where volume is increased would not lead to any increases in structural adaptations. Again, I know what you are thinking. Maybe structure isn’t the most important thing here. Keep thinking like that.

IMPLICATIONS - OR ANOTHER WAY TO VIEW THIS

1. LETS STAY IN THE STRUCTURE WORLD

If structural failure/damage/strength is an important variable in running related injuries we all probably have a genetic limit that can’t be greatly influenced. You might be able to run 60 km/week and that might be your limit and you could probably reach it quite quickly in your training life. It could increase, but it would increase with just the 15-20 minutes of mechanical load that our body will listen to. Meaning, you can’t force it. It would take years to change your pre-determined threshold.

2. INJURIES AND ADAPTABILITY ARE ABOUT WAY MORE THAN TISSUE RESILIENCY

This shouldn’t need to be said but here we go. This means that many of the running related “injuries” we get aren’t really about injuries. They could be about our neuroimmune reaction to physical stress. Nociception is influenced by chemical processes and nociception on its way to pain is influenced by so many things. A small amount of training does seem to change our tissue but training would also influence all the other systems in our body. A slow progression of training volume (when you listen to your body) might be training a multitude of systems that are far more important than tissue resilience. And it could certainly be these systems that are most important in safe adaptability and running.

3. CROSS “TRAINING” IMPLICATIONS

I don’t think its fair to discount tissue injury when it comes to running related to pain. It still might be relevant. Strength training and plyometrics could all potentially stimulate tissue adaptations that could make the tissue stronger. But, if assumption #2 holds we could suggest that these workouts be done 4-6 hours from a run and might only need involve 10-15 minutes. Or maybe our cross training needs to develop some other physical attribute that a runner needs (e.g hypertrophy) to run safely. Conversely, we could also argue for the value of running 2x/day, spaced 4-6 hours apart. Which many runners have done for centuries.

Last, if we take a more holistic approach and recognize that many running pain problems are not about just tissue “injuries” then we need to get better at identifying and implementing interventions that improve other systems. I still consider running itself to be the best way to PREPARE someone to run.

Greg Lehman