scholarly journals Shear elastic modulus is a reproducible index reflecting the passive mechanical properties of medial gastrocnemius muscle belly

2016 ◽  
Vol 5 (4) ◽  
pp. 205846011560400 ◽  
Author(s):  
Masatoshi Nakamura ◽  
Tome Ikezoe ◽  
Hiroki Umegaki ◽  
Takuya Kobayashi ◽  
Satoru Nishisita ◽  
...  
Healthcare ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 80
Author(s):  
Masatoshi Nakamura ◽  
Ryosuke Kiyono ◽  
Shigeru Sato ◽  
Kaoru Yahata ◽  
Taizan Fukaya ◽  
...  

Background: Previous studies suggest that the capacity for rapid force production of ankle plantar flexors is essential for the prevention of falls in the elderly. In healthy young adults, there were significant associations between rate of force development and muscle stiffness measured by shear wave elastography. However, there has been no study investigating the association of rate of force development with shear elastic modulus in older adults. Methods: The muscle strength and shear elastic modulus of the medial gastrocnemius muscle in both legs were measured in 17 elderly men and 10 elderly women (mean ± SD; 70.7 ± 4.1 years; 160.6 ± 8.0 cm; 58.7 ± 9.5 kg). We investigated the rate of force development of plantar flexors and shear elastic modulus of medial gastrocnemius muscle using by shear wave elastography. Results: Our results showed that there were no significant associations between normalized rate of force development and shear elastic modulus of medial gastrocnemius muscle. Conclusion: This suggests that the capacity of rapid force production could be related not to muscle stiffness of the medial gastrocnemius muscle, but to neuromuscular function in older individuals.


2020 ◽  
Vol 6 (1) ◽  
pp. 62-64
Author(s):  
Charles Nichols ◽  
Elizabeth Liu ◽  
Howe Liu

Sarcopenia and infiltration of intermuscular adipose tissue are often seen in older adults due to aging process, but a muscle is completely replaced by adipose tissue is rarely reported. In this cadaveric case, we describe an observation of bilateral symmetric adipose replacement of the medial gastrocnemius muscles (GM) on both left and right leg in an 82-year old Caucasian female, whose cause of death was advanced dementia. The white adipose tissue replaced the entire medial GM muscle belly with pennate-like arrangement, indicating adipose tissue infiltration very likely into the original muscle cells. Where and how these adipose tissues come from are discussed.


2001 ◽  
Vol 536 (3) ◽  
pp. 893-903 ◽  
Author(s):  
N. P. Whitehead ◽  
J. E. Gregory ◽  
D. L. Morgan ◽  
U. Proske

1993 ◽  
Vol 342 (1302) ◽  
pp. 321-333 ◽  

Several of the models proposed in the literature of unipennate muscles, which have two tendinous sheets and in-line tendons, cannot meet the criterion of mechanical stability. Based on the theory of Van Leeuwen & Spoor ( Phil. Trans. R. Soc. Lond. B 336, 275-292 (1992)), we discuss how mechanically stable solutions for (planar) unipennate architectures could be obtained. A mathematical model is proposed in which the muscle architecture is generated numerically using the principles of mechanical stability and assuming that all muscle fibres shorten by the same relative amount. The tendinous sheets are attached tangentially to their respective tendons, as predicted from their low bending stiffness. The curvature, however, is discontinuous at the junction because of the sudden absence of muscle fibres from aponeurosis to tendon. In two of the muscle shapes generated, the sheets adjacent to the tendon show a region of negative curvature connected to a region of positive curvature. A sheet with a concave outer side is defined to have a negative curvature. In another example, two negative curvature regions are present with a positive region in-between. We show also a generated shape with a negative curvature of the sheets over their whole length. A good resemblance was found between the unipennate medial gastrocnemius muscle of the cat and a simulated architecture. The pressure distribution has also been calculated. With all muscle fibres exerting the same tensile stress of 200 kPa, a high pressure region is present in the centre of the muscle belly, half-way along its length. The highest pressures are predicted for muscles with long tendinous sheets, large attachment angles, and strongly curved fibres. Maximum pressures (2.40, 9.54, 10.47, and 7.57 kPa for the four discussed examples, and 15.05 kPa for the simulated gastrocnemius muscle) were at the lower side of the range as predicted previously for bipennate muscles and the unipennate medial gastrocnemius muscle of man (Van Leeuwen & Spoor 1992).


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