If you haven’t read our part one in our series, check it out here.
In part one we discussed how capacity is a measure of quantity of the tissue’s capacity to produce/resist power/strength/endurance. Skill is a measure of movement quality. In part 2, we’d like to delve further into movement quality and skill acquisition. Movement quality is difficult to measure, while there are agreed upon general ideas such as “bad posture”, “hunching forward”, “poor knee alignment”, quantifying “how bad” they are is not straightforward as they are more qualitative rather than quantitative.
We use the Functional Movement Screen (FMS) here in our clinic to classify various movements into 0 (painful), 1 (poor), 2 (average), 3(optimal), but we are aware that others may use a different system to rank movement quality, so we will try to avoid using that ranking system so this may be more understandable to more people.
As clinicians we mostly deal with movement quality in relation to pain and health impairments with a health goal in mind. For example, with the goal to be able to squat pain-free, poor hip-knee alignment control during a squat resulting in the knee caving in may result in pain. However, what we also see is how movement quality can improve performance. Usually this relates to efficiency; efficiency is how much energy is consumed compared to how much of that energy is useful. This can be lifting a box off the ground, throwing a ball, or even running.
Let’s take running as an example. Running is basically an activity where you push the ground backwards and downwards to propel you forwards. The backwards push on the ground results in an equal and opposite reaction force which pushes you forwards (Newton’s Third Law) and the downward force results in an equal and opposite reaction force which pushes you upwards (also Newton’s Third Law). The forward force is fairly obvious; face the direction you want, and the forward force pushes you to that direction.
The upward force is only required to counteract gravity, that is pulling you down. This means any amount more than gravity of upward force, is wasted energy, because gravity will pull you down anyway; this often result in the “bobbing up and down” running. That energy can be used to propel you forward instead - wasted energy =inefficiency. By the same notion, any horizontal force that is not pushing you forward (e.g. overstriding pushes you backwards) or sideways force is also inefficient because you either have to fight it (backwards force) or correct it(sideways force need an opposite sideways force to keep you going forward).There are exceptions to this rule, especially if you are running on a track on a curve or intentionally making a turn. However, backwards force and sideways force also cause inefficiencies. Inefficiencies = wasted energy that could have been used for better performance. If you want to have a look at how these inefficiencies may affect you on a treadmill, check out our previous post here:
http://www.focusphysio.co.nz/blog/2019/11/19/motorised-treadmills-a-cautionary-note
So basically, to maximise performance, apart from getting better tissue capacity, we need to minimise inefficiency, usually this means a skillful technique, be it throwing a ball, or running - which normally equates to good movement quality.
So what do we need to acquire good skill or movement quality? Well, movement quality does not take into consideration how fast or powerful your movement is, just the actual movement. Generally this requires two things: enough mobility and enough motor control - the keyword here is enough.
If we go back to the running example, to be able to produce force in the backward direction (resulting in the ground pushing you forward), you need to be able to have some hip extension (how much is up for debate) while maintaining a forward facing foot. If your foot tends to turn in/out as you push backwards, you will create sideways force instead of a pure backwards force. If you don’t have hip extension mobility in the first place, you will not be able to do this and you will be inefficient. This is why mobility is vital, if you don’t have the required mobility to perform an efficient movement, you will not have an efficient movement. Usually the counter-argument for this is, “I have enough mobility if I push past the stiffness”. While yes that is true, but that would mean, some energy would be used to “push past the stiffness” - just another form of inefficiency from insufficient mobility which may affect performance. Different mobility requirements apply to different activities, such as trunk mobility for throwing or ankle mobility in squatting.
What about motor control?
This generally implies being able to use various muscles together, to perform a movement. For a technical skill, this can be a quite precise movement, such as bowling for cricket. It requires the person to have good control over the mobility he has and turns it into a usefulmovement. Generally, you can break down complex movements into simple ones. For example, back to the running, the runner must be able to bring their leg forward and backwards without turning in/out; this can be tested outside of the actual running motion and starting with easier positions, such as lifting their leg straight up while lying down without turning in/out (Active Straight Leg Raise). If they cannot do the simpler motion, it stands to reason it will be harder when they have to do it multiple times during running, with body weight and speed. The more technical the skill is, the better motor control you will need.
A cricket bowler for example needs to be able to produce force effectively with their lower body, but also be able to transfer that force into their upper body and ultimately into the ball they are throwing. Any loss of motor control in that process (foot, ankle, hip movement, torso, shoulder)would result in an inefficient bowl and a less than optimal performance. Complex movements such as these are still usually composed of multiple simpler movements, if they can’t do the simpler movements, it would likely affect the quality of the complex movements, resulting in inefficiencies and loss of performance.
How do you improve mobility and motor control?
Mobility is usually obtained either with mobility-type drills (stretches/banded mobilisations) or therapist-administered intervention (e.g. manipulation). Motor control requires first: to have enough mobility for the movement, and second: to have some kind of feedback to tell you about the quality of the movement you are doing. This feedback can be done in many ways, be it another person (coach/therapist)commenting on your movement quality, a mirror, a recording of yourself, pulling a band at your knees, your own “feeling” and perception, any of these can be used as feedback. The point of the feedback is to give some kind of indication of movement quality. So that you can improve it to be better in the next set/rep/session. Unlike tissue capacity training, which requires an appropriate exercise and repeat it the same way for an x amount of sets/reps/time; motor control training should result in a different movement with each feedback, hopefully getting better quality each time.
Going back to our first post, we talked about how performance is dependent on 2 factors: tissue capacity and skill. Tissue capacity is generally developed by exercise over a number of weeks and months and is measurable/quantifiable. Skill is about movement quality and is difficult to measure. Movement quality requires enough mobility and enough motor control to produce an efficient movement which results in performance. Developing tissue capacity involves finding the correct exercise and repeating the same exercise many times, while developing movement quality requires changing and improving upon the movement. These are some of the guidelines we would think about when performance is the goal. Usually therapists, coaches, even yourself may have a role in improving performance, and combining them to address every part of performance may allow you to improve efficiently and effectively.
