Rehab & Injury Prevention in a Fatigued State
I stumbled across an interesting new study that showed that soccer players are most at risk for injury near the end of each half. With a little bit of thought, this makes complete sense. Injuries must be higher as the players get more fatigued. I began looking at more research and found this to be true in many different sports as well. Using this premise, I began looking into why this is the case.
Before we get to that, you may be asking, well what about the classic idea of someone not being warmed-up enough before activity and getting injured? There is certainly merit to this observation. Intense activity coming out of a resting state can be problematic because our mobility isn’t totally there, the neuromuscular patterns of firing aren’t working at full strength, and the normal resting body temperature isn’t optimal for musculotendinous structures to support a rapid increase in stretch or load.
For weekend warriors and regular exercisers this is certainly a concern, and I would guess that had the statistics been run on these groups of people, the injury rates would be highest immediately following the initiation of activity. With these groups, it certainly is important to educate them on some basic warm-up techniques to reduce injury.
Athletes, however, understand the importance of warming up very well (usually the higher the level at which they compete the more the more time/energy they devote to warm-up) and for the most part, they do a great job of getting their bodies into prime condition to begin training/competing. For this reason, the research doesn’t show that huge spike in injury at the beginning of activity as might be expected. So this leaves us with looking at why the spikes in injuries occur towards the end of halves, quarters, or periods, and how fatigue plays a role.
Fatigue: What is it and Why Does it Matter?
Science traditionally has looked at fatigue as the result of something that’s happening in the tissues (particularly muscle tissue) that’s causing them to stop functioning effectively. We’ve all heard about “big bad lactate”. For a long time we thought that this byproduct of fuel metabolism was poisoning our tissues and causing that burning feeling, but now it’s looking more and more like it’s our metabolic friend and not the enemy. Science has also hypothesized other changes in the muscle that result in fatigue, most notably leaky calcium channels, increased phosphate and hydrogen ion levels, decreased glycogen stores, and hypoxia. All of these fall under an umbrella that we call “peripheral fatigue”.
The more modern view of fatigue is that it’s not peripheral, but instead, is central in nature. The idea is that fatigue results from a change in brain function and motor patterning which makes sustaining muscular function difficult. The change in brain function is hypothesized to come from an overheating of the body, a decrease in blood oxygen levels, or a decrease in blood glucose levels, all of which are believed to trigger a shutdown, or slowing in activity, of certain areas of the brain including proprioception, motivation (arousal), and motor coordination.
So which theory is right? I personally tend to side with the more modern central theory of fatigue and the idea of “anticipatory regulation” of activity, but that being said, we really don’t have a definitive answer. (As an aside, while doing research for this post I came across a great series of articles on fatigue and the role that anticipatory regulation might play in pacing ourselves during activity. While outside of the scope of this post, it’s a good read and if you’re interested, click on the link at the bottom of this post.) Regardless of which theory you prefer, the end product of fatigue is the same- a decrease in muscle firing and patterning leading to a breakdown in biomechanics/kinematics, and ultimately, injury.
Training in a Fatigued State
For trainers and coaches this isn’t a new idea. They’ve known since sometime around the beginning of sport that when athletes are tired their form breaks down, often causing a decrease in performance, and sometimes leading to injury. Pretty much all elite athletes are routinely trained at the height of fatigue to be mentally and physically tough and to still be able to perform even while the body is slowing or shutting down. Why then don’t we routinely stress the importance of addressing biomechanics, rehab, and injury prevention in the fatigued state?
The Law of Training Specificity states that one will make the most gains in the areas which are specifically trained and under the specific conditions in which the training takes place. I suggest that we apply this to our rehab and biomechanics training. By having our athletes train to have the correct movement patterns and muscle firing during the stages in which there’s the highest level of breakdown, I imagine we’ll see a decrease in injury rate.
Now I know that many of you guys out there are already doing this, and to you I say well done. I also understand that for another big chunk of therapists, the time that you get with athletes isn’t during or immediately after training, and it’s hard to yank an athlete out of training at the height of their fatigue and have them work glute firing or proper movement mechanics.
My suggestion is to teach the athlete initially when they aren’t fatigued. It’s hard to maintain performance and mechanics in the fatigued state, it’s almost impossible to pattern new movements or skills. Once they have a good grasp on whatever exercise/movement pattern you’re working on, have them try it immediately following, or during a break in, a training session, sometime when they feel fatigued. Ideally, either you or a coach/trainer can watch and cue them for at least the first couple times they do it while fatigued. The goal is that once they start to pattern correctly in training, they won’t have to think about it at the heights of performance.
In my opinion, stressing the importance of proper mechanics when fatigued has to be something that we bring into the athletic consciousness. Injury prevention and biomechanics training should be a part of any workout in the same way that warming-up and cooling- (or warming-) down are. Train your athletes to focus on biomechanics when it’s most difficult to do so, the effect will be one of decreased injuries and increased performance.
As always, if you have any questions or comments don’t hesitate to contact me. Below is a link to some good in-depth reading on fatigue and anticipatory regulation:
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