Monday, July 16, 2012

Impingement No More: Study Outlines 6 Week Protocol That Reduces, in 15% of the Cases Even Resolves Shoulder Pain

Image 1: A 1990 study by Lo et al. reports that 43.8% of athletes who are competing in sports with upper arm involvement complain about shoulder problems, 29% with constant pain (Lo. 1990)!
If you are thinking about sex, lies, ex-presidents and obese interns at the White House, when you hear the word "impingement" your language proficiency is not the best and / or you are one of those guys (or girls) who prefers his gossip weekly over the latest issue of a fitness, let alone a bodybuilding magazine (unlikely for SuppVersity students, but who knows?). If you don't belong to this group and / or have just begun to massage your aching shoulder, however, the results of a recently published study on the effectiveness of a 6-week scapular muscle rehabiliation exercise regimen that was specifically designed to alleviate the pain and improve the limited flexibility of athletes with mild to moderate shoulder impingement could be of great interest to you.

The scientifically proven 6-week anti-impingement protocol

For their trial, K. De May and his colleagues from the Department of Rehabilitation Sciences and Physiotherapy of the Faculty of Medicine and Health Sciences at the University Hospital in Ghent, Belgium, recruited 47 athletes (25 men and 22 women; mean 24.6 years); BMI 22.70kg/m²) who had been spending 6+ hours a week playing competitive overhead sports [volleyball (17), tennis (10), canoe polo (2), baseball (2), swimming (11), and badminton (5)] and had been suffering from recurrent or constant shoulder impingement symptoms for at least 3 months. After an initial screening in the course of which the impingement was diagnosed by experienced practitioners, the subjects were assigned to a pretty simple, daily exercise program that consisted of four exercises
  • Image 2 (De May. 2012): Images of the exercises in the same order as in the description to the left: Prone extensions, forward flexion, external rotation, horizontal abduction + external  rotation from 90° position of flexion
    Prone extension (view) - The subject is prone with the shoulders resting in 90° of forward flexion. From this position, the subject performs bilateral extension to a neutral position with the shoulder in neutral rotation. 
  • Forward flexion in side lying (similar, but lying on the side)- The subject is in a side-lying position, with the shoulder in neutral. The subject performs 90° of unilateral forward flexion in a sagittal plane.
  • External rotation in side lying (view) - The subject is side lying with the shoulder in neutral position and the elbow flexed 90°. From this position, the subject performs 90° of external rotation of the shoulder with a towel between the elbow and trunk to avoid compensatory movements.
  • Prone horizontal abduction with external rotation (like this, but with arms in position shown in image 2) - The subject is prone with the shoulders resting in 90° of forward flexion. From this position, the subject performs bilateral horizontal abduction to a horizontal position, with an additional external rotation of the shoulder at the end of the movement.
à 3 sets of 10 repetitions each, with 1 minute rest between sets and a weekly randomized exercise order (to ensure you train all muscle parts equally and don't just replace one imbalance with another one). Before and after the 6-week intervention period, the participants had to answer a standardized questionnaire (the Aside from a questionnaire, the so-called "Shoulder Pain and Disability Index" (SPADI; cf. Brechenridge. 2011) and were hooked up to an EMG apparatus to measure their specific muscular activation patterns.
Figure 1: Pre- and post maximum voluntary isometric contraction (MVIC) in manual muscle test positions specific to each muscle of interest (value expressed relative to mean EMG activity for all 4 muscles; left) and absolute changes in EMG activity during arm elevation (right) from pre- to post intervention (De Mey. 2012)
The MVC data in figure 1 (left) was obtained in manual muscle test positions specific to each muscle of interest and in 5-sec MVIC intervals with 5 seconds breaks in between the activation. And yielded the following insights (De Mey. 2012):
  • all 3 trapezius muscle parts exhibited increased maximum voluntary isometric contraction (MVIC) values after the exercise program (figure 1, left)
  • all 3 trapezius muscle did contract less forcefully during arm elevation, while no change was seen for the serratus anterior (figure 1, right)
  • the upper trapezius to serratus anterior (UT/SA) ratio significantly decreased after the training program, whereas the UT/ MT and UT/LT ratios did not change (data not shown).
Image 3: Illustration of the anatomy of the subacromial space
The significantly improved Shoulder Pain and Disability Index (SPADI) score (29.86 to 11.70 after 6 weeks; .60% reduction on average; 7 patients were basically pain-free after 6 weeks!) has therefore to be considered a result of a combined reduction of trapezius activation (not strength!) during the scapular plane elevation and the concomittant increase in the UT / SA ratio, which probably left more space for the impinged tendons to pass through the narrow subacromial space (see image 3).

Judged based on the results of other studies and what is generally described as a significant improvement in SPADI scores (8-13.2pts) in the literature, the researchers point out that
...[i]n our study, this was the case in 23 athletes. In 7 players, full recovery was attained based on a SPADI score of 0 during postmeasurements. The results of this study are very promising since limiting shoulder symptoms in active overhead athletes suffering from persistent mild symptoms might serve as a secondary injury prevention measure, limiting continued low-grade shoulder pain, fear avoidance, and ultimately surgical management requirement. (De Mey. 2012)
If the prospect of surgery-free total pain relief is not enough to invest a couple of minutes into rehab everyday, you are either the laziest slacker, I know, or don't know how f*** bad that hurts and how debilitating a chronic injury like this can be!

Implications: So, regardless of whether your shoulder does already hurt or you are smart and willing enough to spend a couple of extra minutes on "prehab" exercises I highly suggest that you
  • don't be stupid and take 2-3 weeks off from all your regular upper body exercises and focus on working on the muscular imbalances which are the underlying reason of existing shoulder pain in 90% of the cases to then gradually resume your regular training with light weights and low(er) volume on all those pushing movement the average gymbro loves to do
  • be smart and incorporate 2 of the exercises into every other workout to make sure that you can preserve your presently pain-free state and don't end up ruining your progress, just because your ego told you that it would look better to do another 5 sets of bench presses than a couple of prone extensions and external rotations
And don't forget to revise your complete training regimen - are you doing the same number of sets for your upper chest and front delts as you do for your whole back? If so, it's about time for a more balanced regimen, one that will not only help you prevent muscular imbalances in the first place, but also facilitate constant progress towards a symmetrical and aesthetic physique.

You Want to Learn About the 'Best' Exercises for Shoulders & Co? Look No Further!

The SuppVersity EMG Series can help you in deciding which exercises should be part of your next workout routine.


  • Breckenridge JD, McAuley JH. Shoulder Pain and Disability Index (SPADI). J Physiother. 2011;57(3):197.
  • De Mey K, Danneels L, Cagnie B, Cools AM. Scapular Muscle Rehabilitation Exercises in Overhead Athletes With Impingement Symptoms: Effect of a 6-Week Training Program on Muscle Recruitment and Functional Outcome. Am J Sports Med. 2012 Jul 11.
  • Lo YP, Hsu YC, Chan KM. Epidemiology of shoulder impingement in upper arm sports events. Br J Sports Med. 1990 Sep;24(3):173-7.