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The Anatomy of Human Motion
Published in Emeric Arus, Biomechanics of Human Motion, 2017
We can find similar examples in a Judo contest. During Judo contests using off-balancing (Kuzushi), opponents push or pull each other, but most of the time they pull each other than push each other. So, during the pulling actions, in addition to the biceps and the brachialis muscle acting as a flexor, there are stabilizer muscles of the shoulder girdle that prevent the dislocation of the shoulder joint. There are four muscles that are the major stabilizer of the shoulder girdle, supraspinatus, infraspinatus, teres minor, and subscapularis. They are called the “rotator cuff.” Each of them has the origin on the scapula and the insertion on the humerus head (see the individual muscles described under Section 3.3).
Dressing Autonomy for Frozen Shoulder Users
Published in Marcelo M. Soares, Francisco Rebelo, Ergonomics in Design Methods & Techniques, 2016
Letícia Schiehll, Fernando Moreira da Silva, Inês Simões
Formed by the articulation of the head of the humerus with the glenoid cavity of the scapula, the shoulder joint is a ball and socket synovial joint—or spheroidal joint—that allows a wide range of movement (ROM), such as extension, flexion, abduction, adduction, medial rotation, and lateral rotation. The shoulder girdle, which consists primarily of the scapula bone and the clavicle bone which move together as a unit, allows the following ROM: elevation, depression, retraction, and protraction (adduction and abduction). Organized in pairs of opposite motions, the referred movements consist ofScapular elevation is the raising movement of the scapula; the opposite motion is scapular depression, which is when the scapula is lowered from elevation.Scapular retraction is when the scapula is moved posteriorly and medially along the back, moving the arm and shoulder joint posteriorly; the opposite motion is scapular protraction, in which the scapula is moved anteriorly and laterally along the back, moving the arm and shoulder joint anteriorly.Arm extension is the backwards movement of the arm; the opposite motion is arm flexion, which is the forward movement of the arm (in sagittal plane).Arm abduction is the movement away from midline; the opposite motion is arm adduction, which is the movement toward midline (in coronal plane).Medial rotation of the arm is the rotation toward the midline, so that the thumb is pointing medially. Lateral rotation of the arm is the rotation away from the midline, so that the thumb is pointing laterally.
Comparative upper-quarter posture analysis of female adolescent freestyle swimmers and non-swimmers
Published in European Journal of Sport Science, 2023
Carolin-Mari Botha, Francè Rossouw, Pieter Willem Adriaan Meyer, Tanya Chantelle de Sousa Camacho
From a sport science practitioner perspective, the repetitive monotonous upper-quarter movement patterns associated with freestyle swimming render young competitive female adolescent swimmers vulnerable to exacerbated functional upper-quarter postural deviations. Early detection of postural deviations with ranges that could predispose adolescent swimmers to fixed postural abnormality and associate movement dysfunction, is suggested. Where possible, and when feasible, the swim training load incurred should be varied/modified before short-term changes in upper-quarter postural alignment progress to longer lasting and fixed adulthood malalignment. Pre-rehabilitative, corrective exercises focused on the strengthening of the muscles of the shoulder girdle, cervical and thoracic spine should be considered for inclusion in the training programme. However, the total training load imposed on the afflicted area should always be kept in mind. In this regard soft tissue manipulation, myofascial release and stretching may be helpful during periods of high training load. A pre-session warm-up that potentiates the intended muscle groups toward desirable movement patterns should be a priority, as is the monitoring of fatigue during training sessions to preserve the desired freestyle technique. Furthermore, sport scientists and coaches – especially those working in secondary school or club settings – should be sensitive to the notion that competitive female adolescent swimmers are vulnerable to functional postural deviations and may possibly consider including posture education and whole body conditioning in their periodization plans.
Forward dynamic optimization of handle path and muscle activity for handle based isokinetic wheelchair propulsion: A simulation study
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
Nithin Babu Rajendra Kurup, Markus Puchinger, Margit Gföhler
The dynamic musculoskeletal model was developed in the OpenSim (Delp et al. 2007) platform, involving the anthropometry and muscle force-generating properties of a 50th percentile adult male based on the work by Saul et al. (2015). The rigid segments of the model included the fixed thorax segment (no spine movement), the right upper arm, the right forearm defined by individual components of ulna and radius, and the hand segment. The model was not bilaterally symmetric and only included the right shoulder and hand segments. The shoulder was modelled as a 3 DOF (Degree of freedom) joint comprising of the elevation plane, the shoulder elevation angle (thoracohumeral angle) and the shoulder rotation angle. The elbow joint is defined by 1 DOF with 0° (extension) to 130° (flexion). The wrist joint is modelled with 2 DOF, wrist flexion and wrist deviation (Holzbaur et al. 2005). The hand supination had to be constrained to restrict the motion of the hand in the plane during the path optimization. The collective motion of the shoulder girdle (humerus, clavicle and scapula) determines the motion of the shoulder joint. Humerus and scapula are articulated by a ball and socket joint, while regressive equations determine the motion of the shoulder girdle, which moves only with the elevation angle. The model included 15 musculotendon actuators, spanning the shoulder, elbow and the wrist joints as shown in Figure 1. A Hill type muscle model, defined by Thelen (2003) was used in this study, including both active and passive muscle force generation characteristics based on the muscle force–velocity and force–length relationships. The lumped muscle model included the 4 parameters (optimal fibre length, maximum isometric force, tendon slack length and pennation angle) used to represent the generic properties of musculotendon units (Arnold and Delp 2011). Elastic and damping joint torques were applied to the model to enforce the joint limits (Rankin et al. 2010). The novel handle based propulsion (HBP) mechanism is located in the parasagittal plane that contains the shoulder joint, with the crank centre coordinate CXY fixed in the global frame (global frame origin at the sternum of the upper extremity model). Cx is the mid-point between the seat reference point (SRP) of the wheelchair and knee joint position of the model, considering the model is in a seated position on the wheelchair. CY is the vertical height from the SRP to the forearm of the model with elbow joint being flexed at 90°.