The shoulder is the most commonly injured joint in swimming. Uncertainty, this injury risk correlates with swimming volume and the more volume, the higher stress at a joint. This makes it imperative to decrease the joint stress with every stroke, for a long, healthy career.
One common stroke flaw is a wide swimming catch during freestyle. It is uncertain how this biomechanical flaw being in a swimmer, but as you'll see a wide swimming catch increases anterior shoulder instability (by stressing the joint capsule and dynamic tissues) and stress at the labrum.
The joint capsule has the role of stabilizing the joint and preventing excessive motion. The capsule is a sheet of ligamentous tissue that connects the shoulder socket of the scapula to the humerus (upper arm), with several regions identified by variations in capsule thickness. Little is known about the capsule and pathologies, but that it is responsible for the common injury adhesive capsulitis (“frozen shoulder”).
Of all the shoulder joints, the glenohumeral joint capsule is most commonly discussed due to its large size. It provides passive stability around the joint, preventing subluxations when active structures are inefficient. A subluxation occurs when the active and passive structures cannot hold the head of the humerus in the correct position. As a result, the humerus migrates out of the glenoid. The majority of subluxations occur anteriorly.
Inside the shoulder joint, there is a layer of cartilage which helps protect rubbing on the head of the humerus with the shoulder blade. This layer can be pinched or rubbed, which causes injuries. Tight muscles, specifically the biceps brachii, can directly pull on the labrum due to their direct attachment.
Around every major joint are multiple bursae, which act as cushioning pads.
These pads help reduce friction in the shoulder to allow movement. During musculoskeletal injuries these bursae commonly become inflamed. This inflammation is known as bursitis which is caused by either excessive rubbing or irritation that can be caused by a variety of structures (for example the rotator cuff tendons).
Theoretically, the hand shoulder travels relatively straight from the shoulder-width apart entry, until the exit next to the body (debate exists on this subject, but no parties suggest the catch should occur outside of the body). This is the safest position for the shoulder and having the hand outside of the body, pushes the head of the humerus forward (increasing anterior laxity) and decreases the contact area of the humerus on the labrum, increasing the stress at the smaller contact area.
This increase in shoulder stress undoubtedly increases the risk of a shoulder injury on the labrum over the duration of a swimming career.
Instead, it is more sustainable to swim with the hand underneath the body during the catch, which will decrease the stress on the labrum.
Practical Implication: Freestyle swimmers (as well as water polo players and surfers) should seek a catch underneath their body with proper body rotation to decrease stress on the labrum of the shoulder. In sprint swimming, less rotation is utilized, so an individualized biomechanical approach is necessary to weigh the risk/benefit of different stroking patterns.
For more information about swimmer's shoulder, consider the swimmer's shoulder system.
Dr. GJohn Mullen
DOCTOR OF PHYSICAL THERAPY
PERSONAL TRAINING WITH NATIONAL STRENGTH AND CONDITIONING ASSOCIATION
Dr. GJohn Mullen, DPT, CSCS is a World renowned expert and speaker in sports training and rehabilitation. He received his Doctorate in Physical Therapy at USC, as well as the Josette Antonelli Division Service Scholarship, Order of the Golden Cane, and the Order of Areté. At USC, he also performed research on swimming biomechanics and lung adaptations in swimming training. Dr. GJohn has worked with multiple professional and Olympic athletes, helping them earn Olympic medals. He is also a sports performance consultant, working with the Chinese and Philippine National Teams.
His dedication to research and individualization spurred him to open COR in 2011. Since 2011, Dr. GJohn has been featured in Gizmodo, Motherboard, Stack Magazine, Swimming World Magazine, Swimmer Magazine, USA Swimming, USA Triathlon, Swimming Science, and much more.
He has worked with the numerous colleges and teams regarding rehab and performance. Before his Doctoral program, Dr. GJohn swam on an athletic scholarship at Purdue University.
At Purdue, Dr. GJohn was an Academic Honorable Mention All-American and was awarded the Red Mackey Award and R. O. Papenguh Award. He also won the Purdue Undergraduate business plan and elevator pitch competition, as well as 1st prize with the Indiana Soy Bean Alliance.
Dr. GJohn was born in Centerville, Ohio and was a 24-time high school All-American Swimmer. Dr. GJohn is still a swimmer and holds a Masters Swimming World and Pacific Swimming Record.