This is an interview with Physical Therapist and Ph.D. (c) Tanya Anne Mackenzie regarding her team's research study: Sorting swimmers shoulders: An observational study on swimmers that presented to a shoulder surgeon. For more regarding her research, see her complete list of research.

1. Please introduce yourself to the readers (how you started in the profession, education, credentials, Shoulderexperience, etc.).

HI Dr John and readers. Thanks for the privilege of featuring on your website and for the platform to share this information with you. So, I am a physiotherapist. I started in the profession because my grandmother was diagnosed with a frozen shoulder when I was in my teens and required physiotherapy. The professional title ‘physiotherapist’ sounded impressive, so I thought I’d like to be able to call myself that one day. It was as silly as that. However, after investigating what a physio did I realized it would be a great profession for me and I have been one for 28 years now. A passion for knowledge has resulted in me pursuing a Masters in Trauma and Orthopedic Management and just this week I handed in my PhD thesis titled ‘Factors that influence the acromio-humeral distance in elite athletes’. It explores the area of shoulder impingement syndromes in athletes. I now await my viva. My physio career has spanned a variety of its disciplines, but for the past 4 years I have focused on specializing in treatment of the shoulder and elbow. I now work at Manchester Shoulder Clinic were we specialize in the assessment, diagnosis and rehabilitation of complex shoulder and elbow problems. We are affiliated with a team of shoulder consultants at the Manchester Arm clinic. The patient base is made up of a broad spectrum of patients and includes professional and amateur sportsman. Recently I have had several publications in peer-reviewed scientific journals and presented at several international conferences on the sporting shoulder. So that gives you a bit of a background as to why I was involved in research in the swimmers shoulder.

2. There is varying statistics on the shoulder injury rate. What does your team feel is the injury rate in competitive swimmers?

Reports in the literature on the incidence of shoulder injury in swimmers show a range of between 23-38% per year. Our team only treats injured swimmers, so we cannot comment on the incidence in the population of swimmers beyond what is already reported in the literature. 

3. What did your study look at?

Our study was a retrospective review of competitive swimmers presenting to the shoulder clinic practice over a 6 year period. Swimmers were included if they were competitive at club level or above and had had a period of failed non-operative management of more than 6 months prior to referral. Retrospective information was collected on age, gender, level of swimming, preferred stroke, investigations, diagnosis, subsequent management, and time taken to return to swimming. From this data, relevant observations and analyses were made regarding the mechanism of injury, diagnoses, management, and return to swimming time. But the main motivation behind the study was to look for evidence to support best management of the injured swimmer’s shoulder.

4. Your study reported scapular control and flexibility. How did you choose these and is there anything else you'd like to test?

This is an excellent question, because quantifying scapular control in clinic is difficult to do without the use of motion analysis equipment and the like. Scapular ControlUltimately, the clinician has to do a subjective evaluation. However, having said this, the clinicians’ observations can be divided according to objective guidelines into distinct categories, thus making the observation more objective, repeatable, and reliable. We combined all patients who would meet any of Dr. Ben Kibler’s categorization of dyskinesia of the scapula and characterized them as patients with “scapula dyskinesia”. This is to say the three types of scapular dyskinesia which include prominence of the inferior angle (type 1), prominence of the medial border (type 2), and prominence of the superior angle of the scapula (type 3) were combined into one group referring to it collectively as “scapular dyskinesia”. In some literature, these are also referred to as winging and pseudo-winging. In our study we used the following categories: 
  • ‘Good scapular control’ – meaning that even if there was a poor resting scapular position there was no dyskinesia on motion; 
  • ‘Excellent scapular control’ – used to describe the group that had both good scapular resting position as well as no scapular dyskinesia on motion;  
  • “Scapular dysrhythmia” – this group consisted of those who had scapular dysrthymia of any type. Classifying these patients into a single group allowed us to sort according to a simple “yes/no” criterion: does the patient present with scapular dysrthymia on motion?
When I clinically test a swimmer’s scapular position, I would be interesting in evaluating whether the scapula was upwardly or downwardly rotated in the coronal plane. This is easily assessed by looking at the position of the root of the spine of the scapula and the inferior angle of the scapula in relation to each other in the vertical plane. In addition, assessing where the inferior angle of the scapula migrates to during elevation gives clues as to how efficiently the scapular upward rotator muscles are working in order to effect and control scapular upward rotation. During the swimming stroke, upward scapular rotation is necessary to elevate the acromion (and thus prevent impingement syndromes) while allowing humeral elevation. Full controlled range (and flexibility) of scapular upward rotation is necessary to enable the forward reach in freestyle (front crawl) stroke.   

5. What were the results of your study?Shoulder-20impingement-201-20copy

There were a number of interesting findings from this study:
1. There was no correlation between swimming stroke and type of injury, although the majority of our patients were freestyle swimmers.
2. Despite the belief that hyperlaxity is associated with shoulder pathology, only 38% of our swimmers had a high score (>6). This is similar to the study by Bak et al., who found a hyperlaxity incidence of 22% in the shoulders of swimmers complaining of pain. 
3. The majority of swimmers had good scapular rhythm, with no visible dyskinesis, even in those with chronic impingement.
4. None of the six who underwent arthroscopy had impingement as the leading indication
5. No swimmers with impingement underwent swimmers shoulder surgery. Their mean period for return to swimming was 1.6 months.  
6. All labral tears required swimmers shoulder surgery and failed non-operative management. 
7. The mean time to return to swimming after arthroscopic labral repair was 2.9 months.
This study showed that the appropriate use of clinical tests and the balance between conservative and surgical treatments lead to good outcomes for swimmers suffering from shoulder injuries. The appropriate choice of treatment along with the advances in imaging and shoulder rehabilitation meant that no swimmers with impingement underwent surgery.  

6. What were the practical implications for coaches and swimmers from your study?

I would say that due to the repetitive nature of the swimming stroke and the volume of training put in by competitive swimmers, fatigue of scapular musculature is a factor in injury. To put this in context, competitive athletes may swim 10,000 to 14,000m (6 to 8 miles) a day, 6 or 7 days a week. This equates to 16,000 shoulder revolutions per week (2500 revolutions per day).This predisposes to fatigue in the muscles of the scapula and shoulder. In swimmers it is often fatigue, not weakness or shortness in a muscle group, which results in short term suboptimal biomechanics in the shoulder, predisposing it to injury. Synchrony between the agonist and antagonist muscle groups is lost when one muscle group is fatigued. It is likely that the serratus anterior and the subscapularis are susceptible to fatigue. Monitoring of swimmers is important during training. Coaches observing a change in stroke pattern, for example the elbow not lifting out of the water in middle recovery phase of the stroke, or the arm entering the water too early, or the swimmer experiencing pain, may need to not only consider stroke technique but, in the competent swimmer, consider whether fatigue is setting in.  Simple pause exercise could be interspersed into the training session drills in the water which counteract this and at the same time provide respite for the fatiguing group of muscles.

7. How do biomechanics and training volume influence shoulder pain and as surgeons, what recommendations do you make on training?

Biomechanics in swimming are important. Faulty biomechanics will result in microtrauma to tissues. Poor scapular position will result in poor glenoid orientation and poor elevation of the acromion, both having consequences for the soft tissues around the shoulder. As shown in our study, 38% of swimmers were hyperlax, indicated by a higher Beightons score. These swimmers will therefore have greater humeral head translations. This necessitates good glenoid orientation to ensure the humeral head is centered correctly in the glenoid. It also necessitates that the musculature controlling the scapula and shoulder is well synchronized to avoid excessive humeral head translations. The training volume can result in fatigue in the muscles which correctly orientate the scapula and control excessive humeral head translations.  Excessive humeral head translations will result in repetitive attenuation of the shoulder capsule and ligaments. 

8. What is the current standard of care for recommending swimmers shoulder surgery?

As our study indicates, if there is labral pathology present, swimmers shoulder surgery results in better results. However, if impingement syndrome is diagnosed, it is better for the swimmer to undergo a period of rehabilitation to improve biomechanics and restore dynamic control of the scapula and of the shoulder musculature. Shoulder-Injury

9. When should a swimmer see a shoulder surgeon for shoulder discomfort?

The earlier that a swimmer reports shoulder pain, the more specific the diagnosis can be. If the swimmer waits to report pain, inflammation has set in, and the pain is more global, masking the inciting symptoms. Global pain has led clinicians to make global diagnoses, such as swimmer's shoulder. Likewise, the treatment is then nonspecific with limited success.

10. Who is doing the most interesting research currently in your field? What are they doing?

McCresh et al., (2015), have been doing research looking into the influence of load on the supraspinatus tendon and how this influences the acromio-humeral distance. Thomson at al., (2011) report that the acromio-humeral distance decreased by up to 11% with sort term loading. This research is interesting because it highlights the need to regulate load in the athletes shoulder.

11. What makes your research different from others?

Our study did not differ from other studies which identified the incidence of impingement syndrome and labral pathologies in swimmers shoulders. However, where it differed was that it was able to illustrate that correct diagnosis and appropriate intervention resulted in a better outcomes.

12. What research or projects are you currently working on or should we look from you in the future?

We have a series of articles that attempt to profile the shoulder in professional golfers and in addition to this have done research to examine the factors with influence the acromio-humeral distance in elite sportsman and hope to have this out for publication soon. In our resent publication in Clinical Biomechanics we published ‘An evidence- based review of current perceptions with regard to the subacromial space in shoulder impingement syndromes: is it important and what influences it?’ which may be of interest to your readers. We have also listed some articles that may be of further interest below. 
Tanya Mackenzie, Dan Bulter, Lee Herrington and Lennard Funk. 
  1. Andrews, J. R., Wilk, K. E., & Rienold, M. M. (2008). The Athlete’s Shoulder, 2e (2nd ed.). Churchill Livingstone.
  2. Mackenzie, T. A., Herrington, L. C., Horsley, I., & Cools, A. (2015). An evidence- based review of current perceptions with regard to the subacromial space in shoulder impingement syndromes: is it important and what influences it? Clinical Biomechanics.
  3. Pink, M. M., & Tibone, J. E. (2000). THE PAINFUL SHOULDER IN THE SWIMMING ATHLETE. Orthopedic Clinics of North America, 31(2), 247–261.
  4. Searching for: swimmer | ShoulderDoc. (n.d.). Retrieved September 12, 2015, from
  5. Smith, M., Sparkes, V., & Enright, S. (2006, October). Scapular rotator muscle imbalance in swimmers with subacromial impingement symptoms. Conference presented at the British Association of Sports and Exercise Medicine (BASEM) Congress, Oxford, UK. Retrieved from