Effects of targeted training regimens on rotator cuff and deltoid muscle for enhancement of speed and accuracy in cricket fast bowlers

Cricket is a major international sport with millions of dollars being spent and earned on the international and domestic scenes. It is a unique sport as it has three different formats that are played at the highest level. Multi-day cricket can be played over two four days (domestic level) or five days at international level with both teams normally involved in two innings of batting and bowling/fielding. One day formats include the ODI’s and T20 or 20/20 cricket. ODIs are played at all levels and involve one innings of batting and bowling/fielding for each team and can last for 40-50 overs (6 deliveries) and around 6 hours. Finally, T20 or 20/20 cricket which is the shortest format involves one innings for each side of 20 overs and lasts around 3 hours. In all three formats players bat, bowl and field, therefore there are many different skills that are required for the game [1].

Cricket is the most popular sport in India and is gaining in importance in all south East Asian countries. Its expansion over the past decades has placed greater demand on cricketers due to increased playing hours and increased performance expectations. Cricket is a dynamic sport that involves many abstract skills and movements. To enhance these skills and movements, many players ensure that their bodies are kept fit and strong. Musculoskeletal pain can occur in various ways while playing cricket: a player being struck by a ball or bat, rapid rotational movements, sliding and diving, collisions with other players and overuse injuries [2].

In anatomy, the rotator cuff is a group of muscles and their tendons that act to stabilize the shoulder and allow for its extensive range of motion. Of the seven scapulohumeral muscles, four make up the rotator cuff. The four muscles are the supraspinatus muscle, the infraspinatus muscle, teres minor muscle, and the subscapularis muscle. The supraspinatus muscle spreads out in a horizontal band to insert on the superior facet of the greater tubercle of the humerus. The greater tubercle projects as the most lateral structure of the humeral head. Medial to this, in turn, is the lesser tubercle of the humeral head. The subscapularis muscle origin is divided from the remainder of the rotator cuff origins as it is deep to the scapula.

 The four tendons of these muscles converge to form the rotator cuff tendon. These tendinous insertions along with the articular capsule, the coracohumeral ligament, and the glenohumeral ligament complex, blend into a confluent sheet before insertion into the humeral tuberosities (i.e. greater and lesser tubercle).[3] The infraspinatus and teres minor fuse near their musculotendinous junctions, while the supraspinatus and subscapularis tendons join as a sheath that surrounds the biceps tendon at the entrance of the bicipital groove.[3] The supraspinatus is most commonly involved in a rotator cuff tear.

The rotator cuff muscles are important in shoulder movements and in maintaining glenohumeral joint (shoulder joint) stability.[4] These muscles arise from the scapula and connect to the head of the humerus, forming a cuff at the shoulder joint. They hold the head of the humerus in the small and shallow glenoid fossa of the scapula. The glenohumeral joint has been analogously described as a golf ball (head of the humerus) sitting on a golf tee (glenoid fossa).[5]

During abduction of the arm, moving it outward and away from the trunk (torso), the rotator cuff compresses the glenohumeral joint, an action known as concavity compression, in order to allow the large deltoid muscle to further elevate the arm. In other words, without the rotator cuff, the humeral head would ride up partially out of the glenoid fossa, lessening the efficiency of the deltoid muscle. The anterior and posterior directions of the glenoid fossa are more susceptible to shear force perturbations as the glenoid fossa is not as deep relative to the superior and inferior directions. The rotator cuff’s contributions to concavity compression and stability vary according to their stiffness and the direction of the force they apply upon the joint.

In addition to stabilizing the glenohumeral joint and controlling humeral head translation, the rotator cuff muscles also perform multiple functions, including abduction, internal rotation, and external rotation of the shoulder. The infraspinatus and subscapularis have significant roles in scapular plane shoulder abduction (scaption), generating forces that are two to three times greater than the force produced by the supraspinatus muscle.[6] However, the supraspinatus is more effective for general shoulder abduction because of its moment arm.[7] The anterior portion of the supraspinatus tendon is submitted to a significantly greater load and stress, and performs its main functional role.[8]