Does an Increase in Supraspinatus Tendon Thickness After Swimming Increase the Likelihood of Future Shoulder Pain?

BACKGROUND: Increase in supraspinatus tendon thickness (STT) resulting from swimming practice has been observed in those with a history of shoulder pain. The magnitude of change in STT after a swimming session and its rate of recovery may be an indicator of future shoulder pain incidence. HYPOTHESIS: The supraspinatus tendons that demonstrate a greater increase in thickness as a result of swimming practice will have an increased likelihood of future shoulder pain in a cohort of competitive swimmers over a period of 6 months. DESIGN: Descriptive epidemiology study. LEVEL OF EVIDENCE: Level 2b, individual cohort studies. METHODS: A cohort of 50 nationally qualified swimmers aged between 14 and 22 years, from 3 open National Swimming Programs in Victoria, Australia, were recruited for this study. Ultrasonographic measurements of swimmers' STT was obtained of both shoulders, before, immediately after, and 6 hours after a single swimming practice session. Data were recorded of any significant interfering shoulder pain at 3 and 6 months after the initial testing session. RESULTS: Stepwise logistic regression models indicated that significant predictors of the likelihood of experiencing significant interfering pain were sex [significant at 6 months; odds ratio (OR) 4.2] and the extent of change in STT immediately (OR 2.3 and 1.3 per mm at 3 and 6 months, respectively) and 6 hours postpractice (OR 1.9 and 1.5 per mm at 3 and 6 months, respectively). CONCLUSION: The current data suggest larger increases in tendon thickness after training are associated with an increased likelihood of future shoulder pain. CLINICAL RELEVANCE: These data may be valuable for monitoring training load and identifying athletes who may have an increased likelihood of shoulder pain.

The effect of swimming volume and intensity on changes in supraspinatus tendon thickness.

OBJECTIVES: To compare the change in supraspinatus tendon thickness (STT) following a high volume (HV) and high intensity (HI) swimming practice in shoulders of elite swimmers. DESIGN: Cohort Study. SETTING: Non-clinical, state swim team training facility. PARTICIPANTS: A convenience sample of eight non-injured state and national level swimmers from a regional swim team were recruited for this study. MAIN OUTCOME MEASURES: Ultrasound measures of STT were collected in response to the two swimming practice sessions. Measures were taken prior to each swim practice; immediately after practice; 6-hours post practice and 24-hours post practice. RESULTS: A significant increase in STT resulted from both the HI and HV (p < 0.05) practice immediately post practice. For the HI practice, the STT remained significantly thicker than pre-practice measures at the 6-hour post practice test (p < 0.05) however no longer significant 24-hours post practice. The difference in the change in STT between the HI and HV practice was significantly different immediately post practice and 6-hours post practice (p < 0.05) however no longer significant 24-hour post practice. CONCLUSION: Ultrasound measures of STT following different swimming volumes and intensities may provide information on shoulder tendon loads.

The effect of previous shoulder pain on supraspinatus tendon thickness changes following swimming practice.

OBJECTIVES: To assess if swimming practice results in changes in supraspinatus tendon thickness, acromiohumeral distance, and occupational ratio in shoulders of elite swimmers with and without a history of shoulder pain. DESIGN: Case-Control study. METHODS: A convenience sample of fifty elite swimmers (14-22 years) were recruited for this study. Groups were defined by the presence (history of pain, N = 37) or absence (pain free, N = 63) of significant interfering shoulder pain within the previous 6 months. The current study analyzed supraspinatus tendon thickness, acromiohumeral distance, and the occupational ratio, through the use of ultrasound. Measures were taken prior to swim practice; immediately after practice; and 6 hours post-practice. RESULTS: No statistically significant difference in supraspinatus tendon thickness, acromiohumeral distance or ratio between shoulders with and without a history of pain were found at rest. Following a swimming practice, both shoulders with and without a history of pain had a significant increase in tendon thickness (0.27 & 0.17 mm; P ≤ .001 & <.001). The increase in thickness was significantly greater in the history of pain shoulders compared to pain-free shoulders (P = .003). At 6-hour post-practice, the history of pain shoulders was still significantly thicker than their pre-practice (rested) levels (P = .007). Despite changes in tendon thickness, the occupational ratio remained non-significant between groups. CONCLUSION: Shoulders with a history of pain show an altered response to swimming practice. The results of the current study have implications for training load and injury management. It should prompt investigation into how the tendon reacts under varying load conditions.