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Effects of Environmental Conditions on Competitive Swimming Performance
Published in Youlian Hong, Routledge Handbook of Ergonomics in Sport and Exercise, 2013
Joshua Guggenheimer, Kasey Young, Dennis Caine
The most frequently diagnosed shoulder injury is known as ‘swimmer’s shoulder’, which is an impingement syndrome that occurs when either the supraspinatus muscle tendon, biceps brachii tendon or both become compressed by the acromion of the scapula, making shoulder motion extremely painful and making swimming almost impossible (Johnson et al., 1987). In one study, 91 percent (73/80) of elite swimmers aged 13–25 years reported shoulder pain, and 69 percent of those examined with MRI (36/52) had supraspinatus tendinopathy (Sein et al., 2010). Bak and Fauno (1997) performed complete physician examinations on 36 swimmers with a history of shoulder injuries and found that 12 swimmers were classified as having a primary impingement and 25 swimmers were classified as having a secondary impingement. In a recent study of 236 female swimmers, ages 8–77 years, 48 (20.3 percent) swimmers had shoulder pain and disability. Other shoulder injuries that can affect a swimmer include directional instability, glenohumerallabral injuries, brachial plexus injuries, acromioclavicular joint pain, arthritis and rotator cuff injuries (McMaster, 1999).
Shoulder problems
Published in Richard Graveling, Ergonomics and Musculoskeletal Disorders (MSDs) in the Workplace, 2018
The supraspinatus muscle runs from the supraspinatus fossa of the scapula (shoulder blade), across the shoulder joint, and attaches to the greater tubercle of the humerus (the bone of the upper arm). It passes over the head of the humerus and underneath the acromial arch of the scapula, a route that makes it particularly susceptible to impingement between these bones. It contributes to abduction of the humerus (moving it sideways, away from the body) and stabilisation of the shoulder joint.
A design tool to estimate maximum acceptable manual arm forces for above-shoulder work
Published in Ergonomics, 2022
Supraspinatus tendon compression, shear, and tension can also increase when the deltoid muscle, which is the primary muscle for abducting and flexing the shoulder, becomes fatigued. The supraspinatus muscle stabilises the shoulder and assists in abduction when the deltoid is fatigued. For above-shoulder work, once the deltoid fatigues, and the force it can generate is reduced, workers will shift to a shrug posture to reduce loads on the shoulder muscles (Fuller et al. 2009). With deltoid muscle fatigue, the humerus is translated in the superior direction and this increases supraspinatus compression (Dickerson, McDonald, and Chopp-Hurley 2020). Shoulder fatigue may also lead to less scapular rotation during upper arm rotation, and this may further increase impingement (McQuade, Dawson, and Smidt 1998, McQuade, Wei, and Smidt 1995). Muscle fatigue is related to the level of muscle load relative to strength (e.g. Maximum Voluntary Contraction, MVC%) and the duration of muscle load (e.g. duty cycle). Fatigue can be controlled by following recommendations from the Maximum Acceptable Effort (MAE) equation (Potvin 2012) or the ACGIH Upper Limb Localized Fatigue Threshold Limit Value (ACGIH 2016). Repetitive, hand intensive work should be designed so that these guidelines are not exceeded.
Comparison of 3 supraspinatus tendon repair techniques – a 3D computational finite element analysis
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
C. Quental, J. Reis, J. Folgado, J. Monteiro, M. Sarmento
Rotator cuff tears are among the most common shoulder disorders. According to Yamaguchi et al. (2006), there is a 50% chance of a person developing a bilateral rotator cuff tear after the age of 66. Of the four muscles comprising the rotator cuff, the tendon of the supraspinatus muscle is the most torn, impacting shoulder elevation and stability (Abrams and Bell 2008; Quental et al. 2016). Depending on the development stage of a tear, conservative treatment is considered the best primary treatment option (Oh et al. 2018). Surgical intervention is usually recommended when the tear is repairable, and the patient responded poorly to conservative treatment. Over the past decades, classical open procedures have been replaced by all-arthroscopy procedures, which produce similar results but with better aesthetics and a smaller risk of infection (Imhoff et al. 2018). The general steps of a surgical intervention include opening holes on the humerus, either by drilling or taping, pulling the tendon back to its place, passing sutures through the tendon and anchoring the sutures to ensure that the tendon insertion remains at its original footprint. Tendon repair can be achieved through different anchor suture techniques, which can be broadly classified into single-row, double-row, and suture-bridge repairs (Cole et al. 2007; Imhoff et al. 2018). Single-row repairs consider anchors placed in a linear fashion, usually 1 to 2 anchors placed laterally, whereas double-row repairs consider a medial row of anchors usually placed at the articular cartilage margin of the anatomic neck and a second, more laterally placed, row of anchors, positioned along the lateral edge of the rotator cuff footprint. Suture-bridge, also known as transosseous equivalent (TOE), repairs are modified double-row techniques in which the medial row is bridged to the lateral row, i.e., sutures from the medial row cross the tendon over to the lateral row (Cole et al. 2007; Lee et al. 2018). Considering that the objective of rotator cuff repair is to restore the normal anatomy and function of the rotator cuff, the ideal repair should have high initial fixation strength, allow minimal gap formation, and maintain mechanical stability until healing is achieved (Smith et al. 2006; Vaishnav and Millet 2010). Double-row and suture-bridge techniques have been reported to provide better biomechanical properties than single-row techniques in cadaveric models (Smith et al. 2006; Abrams and Bell 2008; Dépres-Tremblay et al. 2016). However, and despite the continuous evolution of rotator cuff repair techniques, failure rates remain high, ranging from 20% to 95% of patients (Dépres-Tremblay et al. 2016; Lee et al. 2018).