Asia is not a region that would be traditionally synonymous with Rugby Union… until now. On the 20th September 2019, Japan will host the 9th Rugby World Cup and will see the greatest rugby nations on Earth collide… literally! The impacts reported in professional rugby have been likened to car crashes (1) and it is a sport that year on year becomes more physically advanced (2). With an increased physicality comes increased injury rates (3) and there is no larger mechanism for injury than tackling (4) with a reported 142-166 tackles per hour (1).
“Concussion” and “the lower limb” account for the main injuries that we see from tackling (3) and undoubtably it will be the management of the former that presents some major talking points this Autumn. Whilst those two injuries make up the majority of time loss in the professional game, an 8-year study of the under-20 program recorded a different prevalence of injury (5,6) with shoulders accounting for the highest injury incidence. This firstly suggests that younger players cope with the demands of rugby differently, but might also suggest that the majority of players travelling to this World Cup have suffered a shoulder injury in their earlier career. So what impact does previous shoulder injury have on rugby players and how can it be addressed?
Shoulder injuries: not a complicated equation.
We are all told about how unstable the shoulder is, but when you consider 60-70% of the total glenohumeral joint (GHJ) stability is reliant on active stability from musculature (7) and you add in those high impacts, multiplied by the volume of tackles, you can see why shoulders pose a risk to both availability and health.
Now, lets consider some other variables for that equation.
One thing we understand is that rugby players in particular with existing shoulder pathologies have altered joint position sense (JPS) compared to uninjured peers with the outer range being significantly reduced when fatigued (8). On top of altered JPS, a lack of appropriate muscle recruitment in the stabilising muscles of the GHJ following injury can lead to decreased lateral rotation and protraction, contributing to anterior translation of the humeral head (9). Remember, the shoulder girdle is only attached to the axial skeleton via the clavicle, so our basis of support for the shoulder is a mobile scapular.
So, we have a multi-planar joint that is heavily reliant on active structures for stability, yet post injury we lose the awareness of that joint in space and then, decreased stability potentially changes the position of the humerus (think proprioceptive feedback from the joint capsule). It becomes a vicious circle.
Key principles to rehabilitation:
Maintaining stability in sporting tasks is going to help increase participation and performance. This stability, going into a big tackle, will require co-ordinated co-activation underpinned by both conscious (“I’m going in for a big hit, I best tense up”) and reactive muscle efficiency (“ooosh he was going quicker than I thought, where’s my arm gone?”) (10). This is something the Athletic Shoulder Test (11) allows us to measure and monitor. Looking at three potentially vulnerable positions for the shoulder, we can assess not only the peak force of a conscious contraction, but also the rate of force; how quickly they can reach their peak. A quicker rate is going to help stabilise with that unconscious reactive contraction.
The video below helps briefly (<2mins) describe some principles of rehab that look at:
- Control. Working on that joint position sense in both a loaded and unloaded manner.
- Strengthening. Especially in those outer ranges that can be easily fatigued (here’s where the ASH test adds value).
- Dissociation. This is basically complex proprioception, distracting the brain with an opposing task, pretty much like patting your head and rubbing your tummy. Can one limb stabilise whilst the other mobilises? Can the trunk move about a fixed shoulder?
Japan to Junior rugby
Shoulder injuries might not be the most prevalent injury we see at this World Cup, but chances are most of the players in Japan will have experienced one at some time. And, if that’s the cream of the crop with the best medical and performance input, what about the hundreds of thousands of players around the world playing below that level? What about those young players watching and dreaming of getting to the World Cup themselves one day? Hopefully this thought process can help with the rehab and maintenance of shoulder injuries all the way down to grass roots and academies.
Paula is a physiotherapist with London Irish Rugby Club in the English Premiership. Twitter @paulat_physio
- Usman, J., McIntosh, A.S. and Fréchède, B., 2011. An analysis of impact forces in an active shoulder tackle in rugby. British Journal of Sports Medicine, 45(4), pp.328-329.
- Pasin, F., Caroli, B., Spigoni, V., Dei Cas, A., Volpi, R., Galli, C. and Passeri, G., 2017. Performance and anthropometric characteristics of Elite Rugby Players. Acta bio-medica: Atenei Parmensis, 88(2), p.172.
- Fuller, C., 2016, November. 11 Epidemiology of rugby injuries. In Science and Football VIII: The Proceedings of the Eighth World Congress on Science and Football (p. 107). Taylor & Francis.
- Fuller, C.W. and Molloy, M.G., 2011. Epidemiological study of injuries in men’s international under-20 rugby union tournaments. Clinical journal of sport medicine, 21(4), pp.356-358.
- Hislop, M., 2017. Injury Risk Factors and Preventive Strategies in Schoolboy Rugby Union (Doctoral dissertation, University of Bath).
- Funk, L., 2016. Treatment of glenohumeral instability in rugby players. Knee Surgery, Sports Traumatology, Arthroscopy, 24(2), pp.430-439.
- Herrington, L., Horsley, I., Whitaker, L. and Rolf, C., 2008. Does a tackling task effect shoulder joint position sense in rugby players?. Physical Therapy in Sport, 9(2), pp.67-71.
- Herrington, L. and Horsley, I., 2009. Electromyographic analysis of selected shoulder muscles during a rugby football tackle. BMC sports science, medicine and rehabilitation, 1(1), p.10.
- Joyce, D. and Lewindon, D., 2015. The athletic shoulder (Ian Horsley and Ben Ashworth). In Sports Injury Prevention and Rehabilitation (pp. 271-285). Routledge.
- Ashworth, B., Hogben, P., Singh, N., Tulloch, L. and Cohen, D.D., 2018. The Athletic Shoulder (ASH) test: reliability of a novel upper body isometric strength test in elite rugby players. BMJ open sport & exercise medicine, 4(1), p.e000365.