Let’s have a little lesson about human anatomy when it comes to mobility and stability. Which joint in the human body do you think can operate and move in the most directions using the most range of motion possible? If you guessed the hip, then you are on the right track, but not quite there. As you will find out from Mississauga personal training, the shoulder joint, also known as the glenohumeral joint offers the body the most mobility. Think about how many things you can do with your shoulder and how disabling it would be to lose range in any direction. We use our shoulders for countless things including picking things up from tall platforms, reaching behind our backs to address an annoying itch, or brushing our hair in the morning. However, like anything in life there is a fundamental trade-off in the human body when it comes to mobility. The more mobility a joint has, the less stable it inherently becomes as a result. To give you a better idea of what I mean, think about the next joint further down (distal) from the shoulder. The elbow is considered a more stable joint than the shoulder, and a main reason why is because of how it limits range of motion in certain directions.
Things you can try during Mississauga personal training:
Now let’s try a little experiment to compare mobility and stability. Don’t go cranking your elbows or shoulders when you try this out, but take your elbow all the way into full extension by straightening it out. You will experience what physiotherapists call a “boney block” which is basically two boney surfaces that come into close approximation to each other, thereby preventing any further range of motion. Now take your shoulder into full extension by moving your entire straight arm behind you as if to reach a wall. A “capsular end feel” is what occurs in the shoulder when you take it into as much range as possible in any direction, This is essentially an elastic, leathery feel that has a certain give to it. The next thing you will try is moving each joint into as many directions (planes) as possible while every other part of the body is kept still (stabilized). The shoulder operates in three different directions (planes) of motion, known as flexion/extension, abduction/adduction, and internal rotation/external rotation. Depending on how you view the elbow joint, some may argue it operates in one plane of motion (i.e. flexion/extension) while others will say it operates in two planes of motion (i.e. pronation/supination in addition to flexion/extension). Regardless, the shoulder operates in more planes of motion than the elbow.
To put it all together, we just tested both the stability and the mobility of the elbow joint and the shoulder joint. When we brought both joints to their extremes of range of motion, we were assessing stability by determining what would block end of the joint’s range. In the elbow joint, there is an abrupt and solid block to movement which offers more stability, while in the shoulder there is an elastic/leathery block that is less stable. When we moved each joint into as many directions as possible, we were assessing mobility by determining the number of directions each joint could move in. The elbow could more in one or two different directions (depending on which personal trainer you ask) which is less mobile than the shoulder that could move in three different directions. For real life evidence of this phenomenon, just think about how many more shoulder dislocations occur than elbow dislocations which is mainly due to shoulder’s inherent instability in holding the arm (humerus) into the shoulder blade (scapula).
The concept of mobility and stability can be applied to any joint of the human body. It is a great way to determine the limitations to the joint as well as how to address pain or stiffness (i.e. a loss of range of motion), and how to train functional movements that maximize the capacity of that joint. Good personal training will address these concepts, using science to guide movement patterns. Also consider looking at a previous post about whiplash injuries to learn more about stability in the cervical spine.