Injury Rate and the Functional Continuum

The functional continuum

The Functional Continuum model provides a 'go to' set of criteria for loading clients safely in the gym with minimal risk of injury and maximal genuine progress towards their goals.

So in this article we’re going to take a look at:

• Why the injury rate in gyms is so high
• How we’re contributing to ‘false gains’ and latent problems (injuries waiting to happen) in our clients
• A set of criteria for moving your clients along the ‘functional continuum’ safely and effectively towards their goals

But first, let's have a quick recap from the last article:

• Tempo failure has occurred when your client is unable to maintain the prescribed speed or timing of an exercise – they start to accelerate the ‘easy’ part in order to create momentum to get through the hard part.
• Technique failure is when your client starts to rearrange their posture and position to recruit other muscles because the working muscles are fatiguing and/or the nervous system is inhibiting further contraction
• Technique failure shouldn’t be allowed with your clients as the risk of injury increases (big time!) and the benefit to the working muscles decreases (crazy to push through technique failure right?!)
• Start spotting when you see tempo failure and cue technique
• When maintaining technique becomes a challenge encourage your client to get the last couple of reps out (while spotting)
• You’ll usually only get one or two more good reps out of a client after tempo failure has occurred and one or two more after technique failure.

Research has shown you don’t need to train someone to failure to stimulate growth or change. You simply need to introduce enough overload to cause some change and then keep that going over time.

Ok, let’s move on to why the injury rate in gyms is so high and then one of my favourite ‘penny drop’ concepts – The Functional Continuum. Enjoy!

Why is the injury rate quite high in gyms?

As mentioned there are a lot of little errors that can be masked if the brain has time to deal with them. Two things shorten the time the brain has to deal with an error

1. Load – because the rate at which a muscle produces force is dictated by the resistance it is under, higher loads mean higher rates of firing. Load also creates momentum which means the reflexes and connective tissues of the body are more challenged.
2. Speed – because the rate at which a muscle produces force is also dictated by the intended speed of the movement, higher speed movements mean higher rates of firing. Speed also creates momentum which means the reflexes and connective tissues within the body are more challenged.

New members turn up to the gym to get results and are willing to push themselves along a bit initially. However, their systems may be in the worst condition at this time and their movements may be ‘rusty’ to say the least.

This is one reason why the injury rate in gyms is actually quite high. Because in our profession you do push people along, loading them up, having them extend themselves, they do get injured and part of the reason for that is that currently we’re not as thorough as we should be in the area of movement analysis, and prescribing exercises that will not harm or put our clients at risk. We also don’t always seek perfect movement but accept ‘good enough’ and concentrate more on load. Our supervision, teaching and monitoring of exercise technique needs work.

Being ineffective in this area leads to two things. Firstly we create a lot of ‘false gains’ with clients. Secondly we stimulate a lot of latent problems to become ‘active injuries’.

‘False gains’ is a term we use to describe progress that is essentially unsustainable or cannot be built on. An example would be a personal best lift completed by an athlete with poor technique. They won’t be able to progress the load much more without eventually being injured and, they will unlikely be able to use the load lifted as a personal best to prescribe their training from as lifting at or around those loads consistently will lead to injury.

Latent problems are simply movement errors (software) or musculoskeletal restrictions (hardware) that are not attended to and become aggravated by excessive overload. It can be as simple as prescribing the wrong shoulder press exercise to someone who is at risk of shoulder impingement because of their posture, job, warm up practices, sequencing of exercises, the plane of movement of the exercise and their willingness to push hard despite all of this.

In order to progress our clients we must first protect them. The only way to protect something is to understand the state of it, and the risks involved in what you are about to do. To this end fitness professionals must improve their ability to understand how movement is created, what errors look like, identify the likely causes, and either refer out or if the issue can be fixed by regressing and coaching the client, deliver on that need.

Creating and controlling movement

What elements are involved in creating movement?

Whenever we move there are a number of elements involved. They include;

1. The joint and bones
2. The connective tissue (fascia) mechanical properties
3. The muscular tissue contractile properties
4. The nervous system

For ease of understanding we tend to refer to the joint, connective tissues and muscular tissues as ‘the hardware’ of the system much like the computer hardware you have. The nervous system we refer to as the ‘software’, again, just like the software that runs the computer hardware.

When a movement is created and controlled:

• The software calls up the pattern
• The software refines the pattern based on the target of the movement
• The software refines the movement as it occurs based on proprioception
• The hardware is stretched and contracted
• The hardware is moved about an axis
• The properties of the hardware are displayed as forces are transferred along the kinetic chains

There is an intricate relationship across the body’s systems when movement occurs and our role is to assess both the risks and benefits of movement to the client. We do this by completing a movement appraisal and by observing our clients at all times.

To better understand movement we can break it down using a model which relates the importance of each element within the movement process. Here’s a diagram representing the model. Click here for full size diagram

Above the line you have the type of performance you are attempting. Below the line you have the behaviour the nervous system is trying to implement.

When you lie someone on their back and manually try to put the joint through a range you are looking at how the joint articulates, whether the nervous system is happy isolating that joint (remember, if the joint is injured the nervous system won’t let you move it as it will lock muscles and connective tissue around it to protect it), and what range of motion you can create.

If you manage to do that and the joint moves well, there’s no pain, and the range is satisfactory for your intended movement then the person has a reasonable chance of getting the software (nervous system) to:

1. Integrate a group of muscles and create joint stability and overall balance
2. Gradate a set of contractions to overcome a resistance – ie display strength
3. Summate to contract a lot of musculature, quickly, to create power

Here’s a summary of what criteria must be met as you move along the continuum

This model is very useful in practice because it allows you to drill down to the issues and understand why a performance may be under done.

As an example, let’s say we get a person who claims they can’t squat. What are the potential reasons for this?

1. They don’t have a good movement pattern built up
2. They don’t have the ability to put all of the joints through the required range
3. They can’t assume the posture demanded to get the load in to the correct start position or to control the forces at various points of the exercise
4. They don’t have the muscle capacity to produce the force required

If we were to use this model to approach this issue we would;

• Test each joint through the range it would be required to go through for the squat, including getting into the correct initial position
• Have them move unloaded to see what the patterning was like and if, with the correct cueing, the pattern could be improved (ie you can tell the nervous system to do things differently and it can tell the hardware and the hardware responds)
• Start with a low load and progress them as they begin to develop the necessary ‘force control’ capacity for the lift. Force control is one element of strength. The other is force generation. In order to do any lift you must be able to control and then overcome the load at each point of the lift. There is a high neural component to this which is why much of the initial strength gain is through neural improvements and not muscular changes. Clients must have time to ‘learn the lift’.

Usually there are some range of motion issues, some force control and some patterning challenges. Given the model, we must first address the range of motion issues as that will then allow stability, strength and power to develop. We need to investigate joint range of motion more closely.

Ok, quick summary:

• Increases in load and speed during exercise amplifies any present movement errors and increases the risk of injury exponentially
• The default setting for most PT’s is to push their clients in the gym and new clients are generally willing to push themselves. However, their systems are likely to be in the worst condition at this stage and their movements ‘rusty’ to say the least.
• Putting up the weights when clients have movement limitations brings ‘false gains’ and stimulates latent problems (injuries in waiting) to become current injuries
• Properly assessing a client’s movement before prescribing exercise allows you to prescribe for any limitations properly, progress your client safely with minimal risk of injury and maximum benefit to your client – all while their confidence (in themselves and you!) increases by the day.