Yesterday, I reviewed a research article that analysed the state of play regarding the rehabilitation of the overhead athlete from shoulder problems back in the mid-1990′s. Here’s an update from the early 2000′s.
Shot put launched (photo by Dirk Hansen)
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What’s the article?
It’s called Current concepts in the rehabilitation of the overhead throwing athlete, by Wilk, Meister and Andrews, American Journal of Sports Medicine, 2002.
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So what’s new?
Well, we’ll come to that. First of all, it’s important to note what’s not new.
Importantly, the authors of this study maintain with Hackney (yesterday’s author) that most injuries to a thrower’s shoulder can be treated with a non-operative rehabilitation programme.
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What’s normal for the throwing athlete?
While Hackney mentions that overhead throwing athletes will likely have greater shoulder laxity, he does not describe athletic norms in detail.
However, Wilk et al. provide an interesting analysis of what factors may need to be addressed in assessing what is normal for the athletic population of a particular throwing sport. They consider the following factors to be important:
Range of Motion – Wilk et al. note that most throwers exhibit an obvious disparity whereby external rotation is excessive and internal rotation is limited at 90 degrees of abduction for the throwing arm. In addition, they note that the total motion (external rotation and internal rotation added together) in the throwing shoulder is equal to the non-throwing shoulder. Finally, they note that throwers typically have greater total motion than non-throwers.
Laxity – Wilk et al. note that most throwers exhibit significant laxity of the glenohumeral joint. This laxity permits the excessive range of motion.
External / internal rotation strength – Wilk et al. note that the external rotation strength of throwers’ throwing shoulders is typically significantly weaker than in the non-throwing shoulder. Conversely, internal rotation strength of the throwing shoulder is normally significantly stronger than the non-throwing shoulder. In addition, they note that adduction strength of the throwing shoulder is also usually significantly stronger than in the non-throwing shoulder.
External / internal rotation balance – Wilk et al. believe that the antagonist/agonist muscle strength ratio is important for good shoulder health. They suggest that the external rotator muscles should be at least 65% the strength of the internal rotator muscles.
Scapular strength – Wilk et al. note that the scapular muscles play a vital role during the overhead throwing motion and therefore that proper scapular movement and stability are important for shoulder function. They note that throwing athletes tend to have significantly stronger depressor muscles of the scapula on the throwing side compared with the non-throwing side.
Scapular balance - in addition, Wilk et al. note that good agonist/antagonist muscle ratios in the scapula are also required for good scapular function but they do not provide a percentage ratio.
Proprioception – Wilk et al. note that throwers rely on proprioception to influence the neuromuscular system to stabilise the glenohumeral joint in the presence of the laxity and large range of motion that throwers tend to have. However, they also note that throwing shoulders tend to have diminished proprioception compared with the nondominant shoulder.
So that’s the background. Now how does that inform the revised approach to rehabilitation?
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Rehabilitation of the throwing athlete
Wilk et al. explain in detail the industry approach to rehabilitating the throwing athlete. They sumarise this with ten key points:
- Never overstress healing tissue
- Prevent negative effects of immobilisation
- Emphasise external rotation muscular strength
- Establish muscular balance (between external and internal rotators and various muscles of scapula)
- Emphasise scapular muscle strength
- Improve posterior shoulder flexibility
- Enhance proprioception and neuromuscular control
- Establish biomechanically efficient throwing
- Gradually return to throwing activities
- Use established criteria to progress
So how does that compare to the approach used in the 1990′s, as described by Hackney yesterday?
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Change from posterior shoulder capsule to posterior shoulder muscles
If you recall, in the article yesterday from the mid-1990′s, Hackney had three interventions, as follows:
- Stretch posterior shoulder capsule
- Strengthen external rotators
- Strengthen scapula stabilisers
Obviously, strengthening the external rotators and the scapular stabilisers are in the list provided by Wilk et al. (see points 3 and 5).
However, what is going on with stretching the posterior shoulder capsule? If you recall, Hackney noted that it was common to see throwers with tightness of the posterior capsule. He explained that this facilitates anterior glide of the humeral head, which pushes the athlete towards anterior instability of the shoulder joint.
Instead of stretching the posterior shoulder capsule, Wilk et al. emphasise posterior shoulder flexibility. They do not believe that loss of internal rotation is due to posterior capsular tightness. They ascertain that most throwers exhibit posterior laxity when evaluated. They believe that the posterior shoulder muscles become tight because of the muscle contraction during the deceleration phase of throwing.
So what else is new?
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A focus on muscular balance, posture and proprioception
Well, in short, the new developments are a focus on muscular balance, the effect that posture can have on scapular position and therefore shoulder function, and the role that proprioceptive exercises can have in rehabilitation. Let’s have a look at those points in a bit more detail:
Balance between external and internal rotators – in all honesty, this isn’t really a new point, as the balance is almost never in favour of the internal rotators. Achieving balance between the external and internal rotators is all about strengthening the external rotators. They like two exercise in particular:
- The side-lying version of the standard external rotation exercise, and
- The prone row plus external rotation (think of a row plus the W out of the YTWL).
Balance between scapula muscles - Wilk et al. note that is is important to assess the resting position and mobility of the scapula. They note that throwers often have a poor posture with rounded shoulders and a forward head. They note that this posture may lead to various problems, including:
Weakness of scapular retractors - muscle weakness of the scapular retractor muscles (rhomboids and middle trapezius) can occur due to their prolonged elongation.
Anterior scapular tilt - in addition, Wilk et al. note that the scapula may often appear protracted and anteriorly tilted in throwers. Anterior tilt of the scapula can cause:
Subacromial (external) impingement – we’ve talked about this before, so I won’t go over it here.
Pectoralis minor muscle tightness - Wilk et al. note that tightness of the pectoralis minor muscle can lead to various problems including arm fatigue, pain and tenderness.
Lower trapezius muscle weakness – Wilk et al. note that the lower trapezius muscle is an important muscle in arm deceleration and that weakness of the lower trapezius muscle may result in improper mechanics or shoulder symptoms.
Key interventions – based on the above analyses, the key interventions are: strengthening the scapular retractors (rhomboids, middle trapezius), stretching the pec minor and strengthening the lower trapezius. Wilk et al. note that where the athlete is particularly sore, isometric movements can be employed, which tend to be much less difficult to employ pain-free.
Enhance proprioception – Wilk et al. suggest that specific drills that should be included in the rehabilitation programme that restore neuromuscular control. Such drills include rhythmic stabilisation and reciprocal isometric muscle contractions for the internal and external rotator muscles.
Why do proprioceptive exercises? Wilk et al. explain that the purpose of these drills is to facilitate agonist/antagonist muscle co-contractions, which help to restore the balance in the force couples of the shoulder joint. Examples of such drills include push-ups on physioballs or medicine balls, to decrease the stability of the point of contact, while still maintaining a close-chain exercise.
How are they progressed? Wilk et al. explain that as the athlete progresses further, plyometric exercises can be introduced into the proprioceptive programme to enhance stability under dynamic conditions and increase the functional workload.
Establish biomechanically efficient throwing – Wilk et al. note that throwing with improper mechanics can lead to shoulder pain or injury, or both, because of the abnormal stresses that are applied across various tissues. They note that determining whether the throw is using improper mechanics will probably require the input of the sports coach.
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New developments: summarised
Essentially, the new developments between the mid-1990′s and the early 2000′s are as follows:
- Stretching the posterior shoulder muscles rather than the capsule
- Concentrating on muscular balance of external and internal rotator strength rather than the strength of the external rotators
- Focus on how posture affects the shoulder girdle and scapular mechanics
- Focus on stretching the pec minor
- Focus on strengthening the lower trapezius
- Use of proprioceptive exercises for the upper body
- Care to resume throwing in a biomechanically efficient way
None of these points will be ground-breakingly new to you but it is very interesting to see how the thought developed so much in the space of five or six years. If anyone has access to a more up-to-date review and doesn’t mind sharing it, I would be delighted to receive a copy.
