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Musculoskeletal system
Published in A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha, Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha
Elbow ultrasound is used in the investigation of: Lateral pain that increases with active extension of the wrist.Posterior pain, particularly in the presence of olecranon bursitis (or student’s elbow) and triceps tendinosis or tear.Medial pain, in the suspicion of medial epicondylitis, worsened by resisted forearm pronation and wrist flexion, or in the assessment of entrapment or subluxation of the ulnar nerve.Anterior pain related to biceps tendinosis or tear.
Torque and moments
Published in Paul Grimshaw, Michael Cole, Adrian Burden, Neil Fowler, Instant Notes in Sport and Exercise Biomechanics, 2019
Similarly, within gym exercises (see Figure C3.5), using the action of “arm curling” with weights requires the consideration of torque. The arm curl is where the elbow is flexed and extended while the athlete holds a weight in the hands. This action requires the biceps brachii muscle in the upper arm to create a torque (or turning moment) in order to resist the turning effect (or torque) created by holding the weight at a distance from the elbow (i.e. in the hand). In order to perform the action, the athlete must exert a force in this muscle that creates a turning moment (or torque) that overcomes the turning effect (the torque) created by the weight at the hands (due to its position in the hand from the axis of rotation (i.e. the elbow joint)). Figure C3.5 and Figure C3.6 help to illustrate this in more detail.
Tissue Structure and Function
Published in Joseph W. Freeman, Debabrata Banerjee, Building Tissues, 2018
Joseph W. Freeman, Debabrata Banerjee
A single skeletal muscle, such as the triceps muscle, is attached at the origin to a large area of bone via a tendon (Figure 4.32). At its other end, the insertion, it tapers into a tendon, which is attached to another bone. Some skeletal muscles are organized into two groups, extensors and flexors (Figure 4.32). These muscles work together they make an antagonistic pair of muscles. This pairing is necessary for skeletal movement because skeletal muscle exerts force only when it contracts. Therefore, you need antagonistic groups that will pull the limb in opposite directions to gain back and forth motion. An example of an antagonistic pair is the grouping of the triceps and biceps muscles. When the triceps contracts, the insertion is pulled toward the origin and the arm is straightened or extended at the elbow; the triceps is an extensor. The biceps muscle is the flexor of the lower arm; it flexes or bends the joint.
Softball pitching mechanics and shoulder injuries: a narrative review
Published in Sports Biomechanics, 2023
Paul D. Minetos, Jeffrey D. Trojan, Symone M. Brown, Mary K. Mulcahey
Uniquely important to the windmill pitch is the activation of the biceps brachii muscle throughout the pitch, maximally from the 9 o’clock position to ball release (Rojas et al., 2009). The biceps both resists glenohumeral distraction and produces elbow flexion torque. The 9 o’clock-to-release phase corresponds to the highest reduction in elbow angular velocity, during which the biceps experiences maximum eccentric contraction. This coincides with a similar finding by Oliver et al., who found that maximal biceps activity occurs from the 12 o’clock position to ball release (Oliver et al., 2011). Of note, Rojas et al. discovered two times greater maximal biceps activity during the windmill pitch compared to the overhand baseball pitch (38% vs. 19% of maximal muscle activity, respectively) (Rojas et al., 2009).
Effects of deceleration-focused exercise strategies on shoulder range of motion and throwing velocity in baseball and softball athletes
Published in Sports Biomechanics, 2021
Sara Garner, Jason Wicke, Samantha Legreaux, Ben Chianchiano
Internal and external rotation occurring at the shoulder during an overhead throw is recognised as one of the most dynamic movements of the human body (Dillman, Fleisig, & Andrews, 1993). Following ball release, the arm experiences a high magnitude of force that can cause joint distraction at the shoulder (Fleisig, Barrentine, Escamilla, & Andrews, 1996). Deceleration of the arm at the shoulder joint is generated by eccentric contractions of the posterior rotator cuff muscles. These muscles act concurrently with the activation of the biceps musculature initiating elbow flexion torque to stop the elbow from reaching full extension (Fleisig et al., 1996). Without sufficient activation of the musculature, both joints become susceptible to injury throughout the motion. To prevent injury it is crucial for the upper extremity musculature to maintain stability and to produce proper mechanics throughout the motion.
A design tool to estimate maximum acceptable manual arm forces for above-shoulder work
Published in Ergonomics, 2022
Shoulder pain is a common and increasing problem among workers, affecting 18–26% during their working life (Linaker and Walker-Bone 2015). Shoulder fatigue, pain and injuries can limit the ability to perform hand intensive work and can lead to high levels of disability, health care costs, and lost worktime and reduced work quality (Jakobsen et al. 2018; Sirén et al. 2019). Common occupational shoulder injuries include supraspinatus tendon tears, subacromial impingement, biceps tendonitis, and shoulder bursitis.