We have now covered the intrinsic factors that contribute to the incredibly high incidence of swimmer's shoulder in competitive swimmers of any age. These anatomical and physiological adaptations occur as a response to the stimulus from training. Improper mechanics paired with muscular imbalances over the course of a season lead to non-traumatic tendinopathies and connective tissue break down over time. Understanding these four training shortfalls can help avoid these problems.
1. Overuse
2. Misuse
3. Disuse
4. Abuse
1. Overuse
Overuse in swimming is performing a task with a frequency that does not allow the tissues and muscles adequate time to recover. When these structures are not fully recovered from the microtearing that training induces, the muscles develop abnormal contractile properties. As a result, the muscles will have decreased strength and stability, putting increased pressure on the connective structures of the body. Apply this to a chronic cycle of a swimmer throughout a season and it's no wonder we see such a high prevalence of imbalances and pain associated with this decreased strength and structural integrity of the musculoskeletal system.
An example of overuse would be a swimmer increasing her yardage in a swim workout from 5000 yards to 10,000 yards per day. At this rate of increase, your body is not able to keep up with the sudden increase in demand resulting in increased time to full recovery. As the muscles become fatigued to the point that they can't hold proper positions, stroke technique and form fall apart further increasing your risk of injury. As coaches, keep this in mind during your season planning. The rule of thumb is do not increase more than 10% of the yardage from week to week. This allows the swimmer's body to slowly build up strength and endurance, without the risk of injury.
2. Misuse
Misuse is using improper form during training, without correction, which puts abnormal stress on the tissues and structures of the swimmer. As coaches, it is our responsibility to address these stroke mechanics as we see them and do not let them become a habit. Once it is a habit, it is that much harder to break and retrain the neuromuscular systems.
One common error is inadequate or excessive body roll during freestyle. A swimmer with excessive body roll may cross the midline of the body during the pull through phase and this increased horizontal adduction can lead to impingement. Whenever the shoulder crosses the midline during any stroke, the arm is in a position of increased humeral internal rotation that causes the the head of the humerus to be compressed in the glenoid fossa. With repetition, this wears away at the connective tissue and tendons that pass through this space. The wear and tear contribute to non-traumatic tendinopathies and break down of other tissues leading to pain!
3. Disuse
Disuse occurs when a swimmer has taken a period of time off without training resulting in atrophy or altered neuromuscular control of the stabilizing shoulder girdle musculature. In all of these cases, the tissues cannot accommodate the repetitiveness, force, or stress that is encountered with a specific activity. When the smaller stabilizing muscles, such as your rotator cuff and periscapular muscles, do not contribute to the dynamic movements of the shoulder joint required for swimming, the larger muscles, such as the deltoids, pecs, and lats take control. Without the foundational strength and neuromuscular control, the body will find the path of least resistance, further perpetuating the faulty mechanics of swimming stroke.
4. Abuse
Abuse is having excessive force going through your shoulder musculature. A swimmer's shoulder is already being put in a vulnerable and extreme position in order to complete full revolutions of any stroke. If a swimmer suddenly adds large hand paddles for extended training periods on top of this, the shoulder girdle will not support this increase in strain.
The below is a diagram adapted from Craig et al. (1985) that identifies the change in velocity and stroke rate with large and small hand paddles over the course of a 100m swim. As you can see, using the large hand paddles resulted in increased velocity with decreased stroke rate. In order to adapt for these changes, the body must exert significant increase in force through the shoulder girdle to propel a larger surface through the water. Over time, studies have linked the excessive use of large hand paddles to the increased incidence in swimmer's shoulder.
Velocity (m/s), stroke rate (Hz) and stroke length (m/cycle) relationship in each 50 m length during three different conditions: without paddles (WP), with small paddles (SP) and with large paddles (LP). Adapted from Craig et al. (1985).
Healthy Shoulder Training Tips
Avoid excessively large hand paddles
Freestyle to backstroke ratio of 2:1
Minimize use of kickboard to maintain body position
Avoid single sided breathing
Avoid anterior capsule stretching
Avoid aggressive wall and partner stretching
Gradually increase yardage
High Elbows during all catch phases
Grandeur Movement Science strives to be your expert in this category and provide the swimming community with the knowledge and tools necessary to prevent these types of injuries.Thanks for reading! Stay tuned for more.
Sam LaRiviere & Dan Fay
Grandeur Movement Science