Differential activation of the plantar flexor muscles in balance control across different feet orientations on the ground

Author(s):  
Júlia Ávila de Oliveira ◽  
Nametala Maia Azzi ◽  
Daniel Boari Coelho ◽  
Luis Augusto Teixeira
2019 ◽  
Vol 9 (1) ◽  
Author(s):  
E. F. Hodson-Tole ◽  
A. K. M. Lai

Abstract Skeletal muscle thickness is a valuable indicator of several aspects of a muscle’s functional capabilities. We used computational analysis of ultrasound images, recorded from 10 humans walking and running at a range of speeds (0.7–5.0 m s−1), to quantify interactions in thickness change between three ankle plantar flexor muscles (soleus, medial and lateral gastrocnemius) and quantify thickness changes at multiple muscle sites within each image. Statistical analysis of thickness change as a function of stride cycle (1d statistical parametric mapping) revealed significant differences between soleus and both gastrocnemii across the whole stride cycle as they bulged within the shared anatomical space. Within each muscle, changes in thickness differed between measurement sites but not locomotor condition. For some of the stride, thickness measures taken from the distal-mid image region represented the mean muscle thickness, which may therefore be a reliable region for these measures. Assumptions that muscle thickness is constant during a task, often made in musculoskeletal models, do not hold for the muscles and locomotor conditions studied here and researchers should not assume that a single thickness measure, from one point of the stride cycle or a static image, represents muscle thickness during dynamic movements.


2019 ◽  
Vol 119 (5) ◽  
pp. 1127-1136 ◽  
Author(s):  
Rasmus Feld Frisk ◽  
Jakob Lorentzen ◽  
Lee Barber ◽  
Jens Bo Nielsen

2020 ◽  
Vol 129 (5) ◽  
pp. 1011-1023 ◽  
Author(s):  
Ricardo J. Andrade ◽  
Sandro R. Freitas ◽  
François Hug ◽  
Guillaume Le Sant ◽  
Lilian Lacourpaille ◽  
...  

This study demonstrates that the mechanical properties of plantar flexor muscles and sciatic nerve can adapt mechanically to long-term stretching programs. Although interventions targeting muscular or nonmuscular structures are both effective at increasing maximal range of motion, the changes in tissue mechanical properties (stiffness) are specific to the structure being preferentially stretched by each program. We provide the first in vivo evidence that stiffness of peripheral nerves adapts to long-term loading stimuli using appropriate nerve-directed stretching.


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