The mechanics behind your shoulder joint
Do you have difficulty reaching your arm out to the side or overhead with ease and control?
Whether you are Roger Federer competing in a major tennis tournament or Joe Soap cleaning shelves in your home, the correct positioning or alignment of your shoulder joint is critical for optimum performance.
Anatomy: Did you know? The shoulder is the most mobile joint in your body with a huge range of potential movement!
- The shoulder joint is a ball and socket joint. This means that the end of the upper arm bone (humerus) is like a ball that fits inside the socket of the shoulder blade (scapula). The socket of the shoulder joint is quite shallow allowing the joint to have a tremendous range of motion making it the most mobile joint in the body.
- BUT this range comes with a price, the shoulder is less stable and generally more prone to injury and dislocation than other joints.
Optimum mechanics of this ball and socket joint when raising your arm – what’s involved?
- One of the key challenges for good, controlled shoulder movement is keeping the ball of the joint centered in the socket. You may have heard of the rotator cuff. This is a group of muscles that facilitate movement by stabilizing the ball in the socket. Injuries to the rotator cuff are common from general wear and tear as one gets older or participates in repetitive movement activities like raising your arm over your head.
- However, the underlying culprit can often lie not within the rotator cuff but within the “mechanics of the shoulder blade”. When you raise your arm the shoulder blade is supposed to upwardly rotate. This allows the rotator cuff muscles to sustain their force and control through a larger portion of the range of motion. The shoulder blade performs this upward rotation through coordinated muscle action. The key muscles are the upper and lower trapezius and the serratus anterior. Frequently there are problems in the strength and coordination of these muscles. Limited upward rotation of the scapula can cause shoulder impingement syndrome which is when the top outer edge of your shoulder blade rubs against your rotator cuff beneath.
- Another mechanical factor that impacts controlled shoulder movement can be a lack of extension in the upper spine due to hours of poor postures in flexed positions. A stiff upper spine may affect the capacity of the shoulder blade muscles as they attach to the spine.
In summary, the importance of good mechanics and alignment is critical when it comes to controlled shoulder movement for optimal performance and injury prevention.
If you have discomfort or lack of power in your shoulder with overhead activity getting a thorough assessment from one of our qualified Ace Certified practitioners will help determine if poor alignment and faulty mechanics may be contributing to your shoulder problems.
Speak to the team at Ace Sports Clinic today to see how we can help you reach your shelves and your goals more easily, through assessment and individual evidence-based treatments and exercise programs to target what may be holding you back.
Written by Michelle Begg
Physiotherapist, Exercise and Manual Practitioner at Ace Sports Clinic, Toronto