All About Joints

Today we will discuss another important topic when it comes to exercise...joints!

First, what are they? It is common knowledge to describe an area of the body that IS a joint (knee, hip, shoulder, etc.), but what are they, really?

  • Defined in the dictionary as the connection made between bones in the body which link the skeletal system into a functional whole; another common term is an articulation of the bones.

  • Within the body, there are 3 types of joints including fibrous (immovable), cartilaginous (partially movable), and synovial (freely moving) ← Main point of discussion today

  • The synovial joints can be broken down as well:

    • Ball and Socket (hip/shoulder), Hinge (elbow/knee), Pivot (forearm), Gliding (wrist), Saddle (thumb), and Planar (ankle)

So to simplify, they are where the bones come together; the center point. And this is important because that center point is where the axis lies; an axis being the center of rotation (think of a bike wheel spinning around the axel it’s attached to). And if we think about all the joints in our body, we are essentially a bunch of different axes moving in coordination with one another.  Pretty cool, right?

Alright, maybe not as cool to some as to others, but here’s why this relates to you and your exercise:  

  1. The biggest point I want you take away is that you only have ONE set of joints, unless you plan on having a ton of surgery later and replacing them all (not ideal)

  2. From a biomechanical standpoint, when we are strength training and using an external resistance (machine, free weight, band, cable, etc.) its relationship to our joint axis will have a HUGE influence on the amount of challenge we feel

  3. Building off of last week’s Newsletter, our muscles will play a big role in how our joints function

Let’s dive into it….

1.ONE set for life!

  • Try this: Think about one of your most prized possessions. Maybe it’s a book, cd, collector’s item, car, a metal sign from your college days, it could be anything really.  Now think of what makes that special? What are some characteristics? I would bet that a big factor is that there is only 1, and even if there’s more than one, there’s only THAT one that matters to you.

  • Now think about your the same things come to mind?  Are they as special as that prized possession? Probably not, but that’s ok, they won’t be mad.  But my point is this, if you only have one set for your whole lifespan, wouldn’t it make sense to protect and nurture them (probably just like you already do with your item of choice)?  To have them function optimally and to the best of their ability, even as we age?

  • But how do we make sure that’s happening?  One major influencer on how well your joints are functioning is exercise!  Joints thrive on movement, they need it to stay healthy. Now going back to week 1, this will vary between individuals, and making sure the exercise of choice is appropriate for you is critical at maintaining joint health (because you can just as easily harm or injure your joints if you’re haphazardly exercising and your body is unable to tolerate it), but it is critical nonetheless. 

    • Exercise also helps in maintaining the function of your muscles and their ability to contract, which we will discuss on why that is important in a bit.

  • So protect them as long as you can through thoughtful and well planned exercise, and they should be thriving well into your later years!

2. As I said initially, our joints are the centerpoint.  They are the axes of rotation. When breaking down this rotational movement, there are a few things to consider.  First, what is producing the rotation? And to answer that we will look at a force known as torque. Torque is a twisting force that produces rotation.

Without getting too deep into the world of physics, just know that in order for our muscles to feel a challenge, there has to be some type of external torque loading occuring at the joint. To figure out how much of a challenge or how much torque, we must determine the shortest distance from the axis to the resistance and the amount of that resistance. Take a look at the example below:

Biceps Curl - Elbow Joint and a Dumbbell

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The perpendicular line or distance from the axis to the resistance is what is known as a moment arm.  As you can see from the figure, it is smaller, bigger, smaller during the range. With the weight/dumbbell staying the same, the main influence on the torque changing will be that distance.  So for this exercise, it is easier at the start, harder in the middle, and easier at the end. Important stuff when we are trying to determine what exercises to do!!  Next week we will dive deeper into that concept.

3. Finally, our muscles dictate a lot when it comes to how our joints are functioning.  If certain muscles are not contracting well, our joints may feel the effects (aches, pain, tightness, etc.).  This is why it is imperative that you have a well rounded strength training program. This will ensure that your muscles are functioning optimally and to the best of their ability.  Happy muscles=happy joints.

So there you have it. Hopefully point #2 wasn’t too dense and if you skipped over it, I won’t be too hurt (well maybe a little, but I’ll live).  But as long as you get the gist, you should be fine. And as always, if you feel that this exercise stuff is more complex than you thought, maybe it’s time to get a professional to handle the heavy lifting ;)  And if you feel like you have it down, keep it going! Your joints and muscles will thank you!

Next week we will dive into a few specific strength training exercises and explain why they may not be doing what you think they are.  Stay tuned!