The acromioclavicular joint (where the acromion, the tip of the shoulder blade (scapula) articulates with the collarbone) is a common area of pain in the sporting population. The AC joint consists of 3 ligaments; the inferior and superior acromioclavicular (AC) ligaments, and the coracoacromial (CC) ligament (which consists of the conoid and trapezoid ligaments). The joint essentially acts as a pivot point to aid in scapular and shoulder motion. 

Whilst acute injuries to this area are typically associated with direct trauma (falls onto the shoulder, collisions in contact field sports), AC joint pain in combat sport athletes, particularly striking athletes, often presents as a gradual onset injury. The susceptibility to pain in this area is increased if an athlete has had an acute AC joint injury in the past. These athletes may often present with the step deformity between the two bones. The attached photo is of my shoulders, and you will notice a difference in the appearance between sides! 

Common causes of AC joint injury are changes in technique and rapid changes in training load, and excessive volume of pressing exercises. Poor scapular control, as well as limitations in thoracic spine (upper back) and hip mobility may place excessive strain on the joint during punching. Changes in training equipment (using a heavier pad/changing from paddles to training mitts) may expose the shoulder to increased compressive load. 

Holding mitts/pads also places compressive load on the AC joint, and this may be particularly relevant for coaches, or athletes also doing coaching, as well as those in a class environment where both parties are taking turns holding pads. 

In part 2 we will discuss pain management.

#thescienceofstriking #boxing #kickboxing #shoulderpain #shoulderinjury #acjoint #rehabiliation #physiotherapy

About the author

Sam Gilbert

Sam Gilbert is a registered physiotherapist with the Australian Physiotherapy Association (APA) and certified strength and conditioning specialist (CSCS) with the National Strength and Conditioning Association (NSCA). He holds a bachelor’s degree in Physiotherapy from Latrobe university (Melbourne, Australia) and a master’s degree in Exercise Science (Strength and Conditioning) from Edith Cowan University (Perth, Australia).

A 3rd Dan black belt in Shinkyokushinkai Karate under the World Karate Organisation (WKO), Sam participated for over 20 years in full contact competition, winning multiple state and national titles, and culminating in a 4th place in the heavyweight division of the Shinkyokushinkai World Cup in 2009.

As the co-founder and clinical director of Club 360, the premier multi-disciplinary health and fitness center in Tokyo, Japan, Sam has combined his practical experience with an in-depth study of sports performance in relation to combat sports, and strives to help other combat athletes reach their full competitive potential, whilst at the same time decreasing injury risk and increasing competition and training potential.

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By Sam Gilbert