Andersson et al. "Risk factors for overuse shoulder injuries". BJSM 2018

Other Discussions Pain Science & Rehab Discussion
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Welcome everyone! I discussed the (large) batch of September articles that he selected to get things started, and we’ve picked a few of the most important/interesting ones to discuss. Future months will have smaller sets of articles, but he wanted to start things off with a bang (and enough to keep everyone busy for the whole month).

One paper in this batch we’d like to get started with was by Andersson et al., titled: “Risk factors for overuse shoulder injuries in a mixed-sex cohort of 329 elite handball players: previous findings could not be confirmed”

Link: https://bjsm.bmj.com/content/52/18/1191

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Please correct me if I’m wrong but these are the takeaways I’ve identified, mixed with some questions of my own.

  1. Scapula dyskinesis isn’t worth measuring during the objective examination as its correlation with pain is unclear.

  2. If point 1 is correct then exercises to improve “scapula control” at best aren’t necessary, and at worse are a nocebo.

  3. Changes in internal and external rotation in comparison to the non-dominant arm or general population are adaptations to the imposed demands of the sport and not precursors of injury. However would IR and ER ROM still be worth measuring in a patient? See point 4

  4. The study reports finding increased IR ROM as a risk factor to injury. They did not find reduced ER ROM as a risk factor for injury, despite previous claims. Does this mean clinicians should now try reduce “excessive” IR in athletes with shoulder injuries? I’d guess not because BBM has previously talked about how the narrative of “tight” or hypermobile structures causing pain is unsubstantiated, as it’s built on the false premise that the tissue is the pain generator.

  5. Would the same logic as above in regards to differences with IR and ER range of motion not being a risk factor to injury also applies to different ratios in IR:ER strength?

  6. The authors are hesitant to embrace their findings. They state “IR stretching should therefore not be abandoned as a prevention strategy” in contrast to there findings. They also say “it appears reasonable to suggest that exercises to strengthen ER should be included in injury prevention programmes” despite finding “no association between ER strength and overuse shoulder injury”. Would this be because they are looking for structural causes of pain/injury instead of psycho-social factors or acute-on-chronic workload?

  7. The study found no association between exposure to high training volume despite “growing evidence supporting a rapid increase in training load as a risk factor for overall injury.” Since the study doesn’t mention how quickly training was load increased, could the athletes simply have adapted to the high training volume over time due to increase in workload being gradual enough to not cause overuse injuries?

Again please feel free to correct me or add something I may have missed

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  1. Yes, most of the time (65%) a finding of scapular dyskinesis reportedly does not go on to develop shoulder pain complaints.
  2. Yes.
  3. The difference in IR & ER ROM was found to be an adaptation to the sport demands and this may phenotypically be reflected in more muscle bulk, although this was not described in the paper.
  4. I don’t think it is the clinician’s responsibility to alter technique biomechanics in the athlete. That would be the sport coach’s job. From the clinician’s perspective, ensuring normal function (not necessarily symmetrical ROM or strength) would be the primary objective.
  5. Muscle imbalances between agonist and antagonist muscle groups are often attributed to an increased risk of injury. This is a logical way for one to predict the onset of injury, but biology refutes logic, often. The idea that muscle imbalance increases the risk of injury has been shown to be inaccurate Psoas and quadratus lumborum muscle asymmetry among elite Australian Football League players - PubMed. The adaptation to the sport demands over time resulting in muscle asymmetry, strength, tendon stiffness, and motor unit firing frequency produce a more rapid rate of torque development, which would likely not be realized when IR ROM is increased as this would potentially dissipate throwing performance and efficiency, thus compromising throwing mechanics and increasing the risk of injury.
  6. It is difficult to predict the likelihood of injury and it would be naïve of the authors to categorically conclude that doing “A” will prevent the occurrence of “B”.
  7. Yes. The average experience of the athletes was 14 years, so they are trained and adapted for the most part. Although there is a wide range in experience described in the paper.