What is Functional Capacity and Why is it Important?

By Andrew Serrano

What is functional capacity and why does it matter?

Functional Capacity is the point at which an athlete is no longer able to maintain ideal locomotor strategies due to the magnitude of the ‘strain’ of a movement. When this strain exceeds the athletes capacities they will revert to a more primitive stabilizing strategy. I was first introduced to this concept by Richard Ulm D.C. in a DNS Weightlifting course. In layman’s terms a person’s functional capacity is the point at which they no longer can maintain ‘good form’ on a given exercise, but can still complete the task.

Even if you’ve never stepped foot inside a gym, you’re likely familiar with the concept of ‘good form.’ Now, while what exactly constitutes good form is a hot topic for debate (hence the quotations), I think most would agree that it exists and there are both more and less ideal ways to complete a particular movement.  When ‘good form’ is in place, the loads on the body are distributed most evenly highly decreasing the likelihood that passive structures (discs, labrums, meniscus etc.) will take on undue stress, therefore reducing chances of injury. Rarely in the gym are injuries produced with one acute action, but are the result of poor movement mechanics over time.

For the purposes of this article, good form refers to the ability to maintain a brace and a neutral spine during an exercise. So, if you haven’t read my article on breathing and bracing you can start with that HERE.  When the athlete is no longer able to maintain good form, they will most commonly revert to an ‘extension/compression stabilizing strategy,’ or ECSS for short. The ECSS is characterized by hyperactive spinal erectors, low abdominal wall activation, and an elevated ribcage (open scissor).

Left – Neutral/ Braced; Right – ECSS/ Scissored 

Why is this bad?

An extension/compression stabilizing strategy contributes to basically every common fault encountered during the major lifts and the chronic discomforts they result in. Butt wink, poor thoracic spine mobility, knee valgus, chronically tight back, poor hip mobility, stress to spinal discs, poor hip activation, and stress to the SI joint. All of these over time will contribute to many of the injuries commonly associated with lifting weights. This is why not only learning how to brace, but really practicing it in all the positions you encounter during training is essential. I truly believe detail in bracing is one of the most overlooked facets of lifting and it will also correct the most issues more so than any one thing you can focus on.

The ECSS can be tempting for lifters to use even unknowingly because it does in fact provide short term success. You will be able to lift more weight faster by using this initially. The problem is not only is your potential ceiling lower and your chance of injury higher, but the stronger you get, the harder it becomes to rewire your form. For me personally, I was able to squat 529 in a meet without even bracing properly, but I also constantly had joint and back pain. Then once I figured this out I had to rework everything from scratch, which is a huge time burden and something most lifters would struggle with mentally. So, get this right from the start – you’ll progress slower, but it will be sustainable.

So how do we avoid it (ECSS)?

When choosing loading parameters for a given exercise we must do so with an intent to stay inside of the athletes functional threshold which can be separated into three categories – load/intensity, speed, and fatigue/duration. If an athlete chooses too heavy of a weight, moves too quickly, or does too many reps/time for what they are capable of they will start to compensate. The main goal in training should be to close the gap between the functional threshold (good form) and absolute fatigue (the point at which the athlete can no longer complete the task even with compensation) in all three categories. Each of these can be trained on separate days, or even the same session, but we will not be going into programming details in this article.

In the first column, we can see that the athlete can only maintain good movement strategies at 50% of their total capacity, and after a training block, or blocks, they can now maintain proper movement much closer to their absolute fatigue threshold, this is the goal.

Threshold training – What does it actually look like?

When I look at my program on a given day, if not already assigned, I try to figure out which of these thresholds am I trying to challenge with a given exercise and I operate as close to that as I can. You must get near the threshold to increase it – if you sandbag your training you will not adapt as quickly.

If the exercise calls for straight weight, let’s say 5x5sets on squats at RPE 8, my main focus is how heavy can I go without losing my brace. If its 24 singles of deadlifts with chains at 70%, since load is predetermined lower, I am going to try to move the weight as quickly as possible. We can add the fatigue threshold to that as well by decreasing rest time which is a favourite of Paul Oneid. Obviously, in powerlifting you don’t want to rest so little that the weights start to decrease too much, so what this actually looks like will vary from sport to sport. For a sprinter, we may do some type of loaded jump with a lot of rest since fatigue is less of a factor where a field, or endurance athlete may do the same drill with less load and less rest.

I find accessory work the perfect time to really challenge singular components of ‘good form.’ Since the movements tend to be less complex, we can really overload certain parameters to challenge particular compensations with a far smaller chance of falling apart.  For me personally, I tend to revert to an open scissor quite frequently on squats and after working on it for two years, it’s gotten much better, but is still improving (yes two years, this stuff takes time). So, one of the ways I’ve been working on this is with hack squats.

I really like the hack squat for correcting the ECSS in the squat because the tracks allow you to squat very deep much more easily and the back pad gives you tactile feedback as to the orientation of your spine and hips. Additionally the shoulder pads give you something to brace against. So, what I do is choose a load and a rest period (usually 60sec) where I can feel myself overextending if I’m not careful, but I use my abs to crunch against the shoulder pads while feeling my back stay neutral on the pad. As I’ve been able to increase the weight and the speed of the reps here, my bracing on my competition squat has been getting better steadily. Here’s a video for clarity.

Another issue I have is overusing my hamstrings and adductors to move my deadlift and not using my glutes enough.  This I’ve found is one of the roots of my SI joint pain (in addition to crappy bracing). I’ve used GHR’s with slow eccentrics keeping the glutes squeezed throughout and performing reps until I can start to feel my glutes give out and my back take over. As I’ve increased reps here, my deadlift mechanics have improved.

The applications are endless. As long as you train near, but within your functional threshold and you apply this concept mindfully to your assistance work (too many people disregard assistance work in terms of the detail they approach it with) you will get stronger with a much smaller chance of injury and ultimately having to rework everything down the line. You can build a house on stilts, but to build a sky scraper you need a solid foundation. If you consistently train beyond your functional threshold, you are building a house on stilts.


To read more from Andrew and to follow his training, click HERE.  While you’re on the site, be sure to watch for the boxing week sales coming up in the store.  Some have started early, like this book bundle from Dr. McGill’s Back Mechanic and Gift of Injury, which he co-wrote with Brian Carroll.

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Andrew Serrano

Andrew Serrano is a full time trainer, holds a B.S. in exercise science and has worked in almost every facet of the training industry. He is currently competing as a 198lb raw lifter, his meet PRs are 589/391/601. His training is guided by the 10/20/Life philosophy with a focus on sustainable injury free progression.
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