Screening your movement is one of the biggest things you need to consider when starting with a programme or a coach. Even before you partake in any activity, an assessment of your background is critical to ensure that there is sufficient information provided about any underlying conditions you may have medically or physically. From a legal perspective, this is to ensure that nothing is done out of the scope of your capabilities.
Whenever I work with someone new, there are 4 main reasons why I want to assess them and I highlight these four reasons heavily to them so that they understand my intentions for them and what they should be looking out for when it comes down to their general movements as well as their weightlifting movements.
1. What You Can Do
It falls under the category of your capabilities. What is your body capable of. Answering questions like how mobile you are, how stable you are, how strong you are etc. Even to the point of saying how well you adopt your positions, how well you move, how well your body awareness is. This basically tell me and you what you can achieve with the current state you are at. This could be as simple as being able to touch your toes.
Understanding this portion of your movement will allow you to empower yourself with the knowledge that at least you are doing something right and not everything needs to be worked on. This empowerment then reminds you that you are still able to achieve progress by making these strengths stronger.
2. What You Can't Do
This is also pretty straightforward like the first point. It is as simple as what the statement is: things that you cant do. For example, you cant feel your shoulders rotate into internal rotation or out into external rotation. You can't sit past parallel in your squat. You can't lock your arms out overhead in a narrow grip. You can't keep your leg straight when raising it up while lying on your back on the floor.
These tell me what your restrictions are and where they lie. Where you struggle to attain a good position. Or where your body awareness starts failing you and you can't get a grasp of what you are doing. Losing that mind-muscle connection the moment you are required to add some velocity to the movement.
3. What You Should Be Doing but Are Not Doing
Now this category of movement is slightly different from what you can't do. The example I give would be your squat. If I break it down, movements like hip flexion or dorsi flexion would be things you probably cant do. So assessing for these can't-dos would be your regular manual testing protocols or range of motion testing. While testing you in your squat pattern would then dive deeper into looking out for where these can't-dos surface from. Going back to the squat, you may not be bracing the abdominals which then limits your hip flexion while dropping into the bottom position.
So this category of movements focuses more on joint coordination, muscle synergies, activation patterns etc. On top of that, there is also the under-rated and bastardised concept of biomechanics. Understanding the structures and the relationship of the structures within the body to better facilitate the movement of the body. The comprehending of lever lengths and how it affects joint coordination. The application of moment arm to facilitate the appropriate activation patterns for movement. This is basically giving meaning to the causes for your restrictions.
4. What You Shouldn't be Doing But Are Doing
Now this is the important one and probably the reason why you would be desperate for help. The mistakes you are making in your positions and movements which are probably causing problems for your body in motion but also affecting two big issues within your training: the inability to improve (aka plateaus) and the breakdown of the body (aka injury).
This is probably the main problem you are experiencing but you just can't figure out why. And even if you know why, you don't know how to fix it. But my answer is always to provide why you don't know how to fix it. Take a hypermobile back for example. The common problem associated with positioning in such a situation is the excessive engagement of the lumbar spine which results in hyperextension. You think you are doing somewhat the right thing because you are bracing the back to support a deadlift or squat. But in fact, you are not keeping the spine in a neutral position which then throws the pelvis out of position which then throws your squat or deadlift out of position because the wrong muscles are firing up to support the position. You think it's the right thing to do because someone or somewhere said you should be arching the back. But what you don't realise is that in such a case, maybe you shouldn't be overextending the back.
Having that background knowledge of what a good position or movement looks like and facilitating the ability to compare your current positions and movements to the ideal would be what will help you progress from here. This is where the correction work comes in. But before the need to understand what a picture of "good" looks like (thanks to biomechanics) compared to what you are current doing (which is "not so good").
So by providing these four reasons for a movement screen, you then get a better idea of your current state, your ideal state and the link between how you can get from your current state to your ideal state. In simple terms, you basically get to understand what your body can do (the strengths), what it can't do (the weaknesses), what it should be doing but ain't (the ideal biomechanics of your body), and what it shouldn't be doing but is doing (the current mistakes you are making).
Then you know the link I mentioned about getting from current to ideal? That's where the fun starts and the work begins.