Rugby-The mechanics of tackling
Mechanics of rugby tackling
The game of rugby has a fantastic history behind it and is the second most popular sport in the United Kingdom. However, with rugby being an explosive high contact sport it comes with its injury risks. In particular, as a result of tackling, the shoulder joint suffers a high proportion of injury. This article will discuss the mechanics of tackling and how this affects the shoulder and more importantly, what can be done to reduce shoulder injuries in the future.
There is not one joint called “the shoulder”. But rather the shoulder consists of several joints articulating with one another. Often considered as the main two joints are the glenohumeral joint and the acromioclavicular (AC) joint. Broadly speaking though the sternoclavicular (SC) joint and scapula-thoracic articulation could also be considered as the shoulder joint due to the closely related mechanics. The glenohumeral joint is the ball and socket joint and can be inherently an unstable joint and therefore cause most injury risk. The large head of the humerus is generally x4 times bigger than the shallow glenoid cavity it sits in. This is due to the evolutionary history of how our shoulders developed requiring a high demand on mobility. As a result stability has thus been compromised and injury risk is high.
Mechanisms of injury
There are three common mechanisms in rugby which cause injury to the shoulder:
- Forced abduction and external rotation (ABER)
- Direct Impact
Forced abduction and external rotation occurs either when tackling or scoring a try. As the picture below shows, tackling involves the tackler’s arm out to the side in an abducted position. As the player with the ball is running at high speed, the tackler’s arm is then forced into extension which causes further abduction and external rotation of the shoulder. This can often lead to soft tissue damage of the surrounding muscles. Soft tissue bruising is common to the trapezius, deltoid and pectoral muscles due to the direct impact of the tackle. Rotator cuff muscle strains may also occur, especially when the arm is in this ABER position which puts most stress on these muscles.
When the shoulder is in an ABER position the passive structures of the shoulder joint are also put under excessive stress and strain. This may result to injuries to the labrum and ligaments as the humeral head is forced posteriorly, causing it to impact the labrum and sprain the anterior glenohumeral ligaments.
Falling is another common mechanism of injury to the shoulder from rugby. This often occurs when a player is scoring a try or falls to the ground on an extended arm. The forces generated cause excessive stress and strain on the shoulder joints, in particular to the AC joint. This could lead to a sprain of the AC joint and laxity to the ligaments, causing pain and restriction of movements overhead and across the body. As a knock-on effect of injury to the AC joint, the mechanics associated can cause excess stress on the SC joint.
A high impact sports such as rugby can also lead to a high amount of forceful collisions. These types of injuries often cause soft tissue bruising. click here for an overview of the most commonly affected areas such as, the trapezius, deltoid and pectoralis major muscles are affected. However, these types of injuries – even though very sore! – Often do not possess long-term concerns.
As a result of the high injury risk rugby can pose, injury prevention techniques and exercises are important to reduce problems such as shoulder injuries occurring in the first place. Here at Response Physiotherapy we utilise specific manual therapy techniques which identify and treat tight structures around the shoulder joint to ensure there is adequate mobility and flexibility. Strengthening exercises are extremely important and we focus on improving the strength and endurance of the rotator cuff muscles in particular which play a vital role in shoulder stability.