|dc.description.abstract||Shoulder injuries, which account for 8% to 20% of volleyball injuries, are usually rotator cuff and / or biceps tendinosis caused by overuse (Briner et al.1999); in addition 38-75% of competitive swimmers have had a history of shoulder pain, while 9 - 35% of these swimmers were currently experiencing pain (McMaster and Troup, 1993). Rotator cuff tendinosis is also found in laborers involved in repeated overhead activities (i.e. among shipyard welders and steel plate workers), with a prevalence of 18, 3% and 16, 2% respectively (Herberts et al. 1984).
Fricker and Hoy (1995), suggest that the principal cause of tendinosis of the rotator cuff muscles is repetitive microtrauma, due to overfatigued muscles and / or weakening of the rotator cuff and scapulothoracic muscles.
The etiology of impingement syndrome is therefore multifactorial and is commonly associated with other clinical entities such as weak or dysfunctional scapular musculature, posterior glenohumeral capsule tightness, inflammation of tendons (viz. supraspinatus and long head of biceps), bursal inflammation and glenohumeral instability (Michener et al., 2003). Shoulder syndromes are often related to the development and perpetuation of myofascial trigger points (TrPs) as found by Hains (2002), who suggested that these TrPs become activated during mechanical stress and overload of the involved shoulder musculature.
Hammer (1991), suggests that the most valuable modality to treat chronic overuse soft tissue syndromes (irrespective of muscular or tendinous in origin) is friction massage to both regions. Cyriax (1984) and Prentice (1994) state the effect of frictions to include the breakdown of adhesions (scar tissue), as well as preventing the formation of further adhesions.||en_US