China
Africa
Explore chapters and articles related to this topic
Centre of percussion
Published in Paul Grimshaw, Michael Cole, Adrian Burden, Neil Fowler, Instant Notes in Sport and Exercise Biomechanics, 2019
The centre of percussion is an important point in the design and testing of a tennis racket and also other striking implements, such as cricket and baseball bats. The point has important applications for hitting effective shots and also hitting shots that minimise the vibrations that are transferred to the wrists, hands, elbows and/or shoulders, which can cause injury (especially through overuse). A common tennis injury that can result from excessive vibrations at the elbow is termed lateral epicondylitis (“tennis elbow”) and minimising the vibrations experienced at this joint while playing can be an advantage to the prevention of this injury. Many tennis racket companies are now seen incorporating anti-vibration devices on the strings and on the racket frame that aim to reduce these unwanted vibrations. However, it is clear that further research is needed to determine the exact relationship between the centre of percussion and the so-called “sweet spot”, as it is so often called in sporting terminology.
Epicondylitis
Published in Richard Graveling, Ergonomics and Musculoskeletal Disorders (MSDs) in the Workplace, 2018
Since that review, further relevant epidemiological research has been published. For example, Shiri et al. (2006) carried out a cross-sectional population study to identify the prevalence and determinants of lateral epicondylitis. The population was 4,698 individuals who were clinically examined. The prevalence of lateral epicondylitis was 2.8% within the sample group. Diagnosis was a mixture of self-report (pain at the elbow) and clinical examination, with tenderness over the lateral epicondyle on direct pressure (possible) and pain on restricted extension (definite) as the diagnostic criteria adopted. Physical load factors were self-reported at interview. A complex multivariate analysis was used to analyse for all cases (possible + definite) or just definite case status.
Biomechanical aspects of the tennis racket
Published in Youlian Hong, Roger Bartlett, Routledge Handbook of Biomechanics and Human Movement Science, 2008
Since most middle-aged tennis players will experience elbow pain sometime in their lifetime (Kamien, 1990; Maffulli et al., 2003), many rackets are marketed with claims about material or design properties to relieve symptoms of 'tennis elbow'. Tennis elbow is the common term for any overuse injury of the common wrist flexor or extensor attachments of the elbow. There is very little research on many of the materials or engineering elements in these rackets, and there are virtually no blinded, prospective studies that would be necessary to examine these claims. This section will summarize the biomechanical studies and logic of recent tennis racket designs purported to decrease the risk or pain from tennis elbow.
A wearable lightweight exoskeleton with full degrees of freedom for upper-limb power assistance
Published in Advanced Robotics, 2021
Chang Liu, Hongbo Liang, Yoshitaka Murata, Peirang Li, Naoya Ueda, Ryuichi Matsuzawa, Chi Zhu
The human elbow joint connects the upper arm to the forearm. It is considered as a hinge-type joint and has one degree of freedom to perform the flexion/extension movement. Hence, the elbow joint of the exoskeleton is designed to be an active joint that is driven by an electrical motor, as shown by Joint 6 in Figures 1 and 2. To make Joint 6 be compact, a flat Brushless DC motor (EC45flat-70W, Maxon motor Co.) and a harmonic gear (CSF-17-100-2A-GR, Harmonic drive systems Inc.) are used. Furthermore, considering the necessary torque of the exoskeleton as well as the rotation speed of the motor, a pulley-timing belt mechanism is adopted for further speed reduction. In such a combination of the harmonic gear and pulley-timing belt, 300:1 reduction ratio of the driving mechanism is achieved. The driving torque of the motor is firstly transmitted to the pulley-timing belt, then to the harmonic gear, and finally to the output part, i.e. the forearm support, as shown in Figure 2(b). The motor, pulley-timing belt and harmonic gear are aligned in parallel in order to reduce the thickness of the joint and the exoskeleton. Figure 2 presents the configuration of the active elbow joint.
The ulnar collateral ligament loading paradox between in-vitro and in-vivo studies on baseball pitching (narrative review)
Published in International Biomechanics, 2021
Bart Van Trigt, Liset (W) Vliegen, Ton (Ajr) Leenen, DirkJan (Hej) Veeger
Strength training is also an important aspect in pitching. Strength training might influence injury risk, since weight lifting during the season was found to increase the risk of elbow and shoulder pain in 8–12 years old pitchers (Lyman et al. 2001). However, this weight lifting was self-reported, which makes it unclear how the training was performed and whether it was conducted under supervision. In contrast, Sakata et al. 2017 found that medial elbow injuries in youth baseball pitchers were significantly lower in their intervention group. This intervention was more sports specific, with nine strength and stretch exercises, compared to the study of Lyman et al.(2001). It seems that strength training programs should focus on motor control to prevent elbow injuries. The effect of strength training in adults has not been investigated.
Immediate effects of counterforce brace with and without vibration on pain, muscle strength and range of motion in participants with lateral epicondylitis. A pilot study
Published in Assistive Technology, 2022
Forough Dehghani, Hassan Saeedi, Alireza Khaghani, Masumeh Bagherzadeh Cham
Lateral epicondylitis (tennis elbow) is a common soft tissue lesion caused by damage to the extensor muscles of the wrist upon overuse (Chumbley et al., 2000). This disorder is characterized by pain and tenderness at the lateral epicondyle of the elbow. The extensor tendons of the wrist, especially the extensor carpi radialis brevis tendon, contract at the site of attachment to the humerus due to a series of specific sports activities such as tennis or repetitive occupations which cause stretching and as a result, pain, and inflammation (Kraushaar & Nirschl, 1999; Shiri & Viikari-Juntura, 2011).