Impaired Neuromuscular Function And Postural Control After A Fatiguing Exercise Performed With The Plantar Flexor Muscles

2015 ◽  
Vol 47 ◽  
pp. 327
Author(s):  
Nicolas Place ◽  
Nicolas Mamie ◽  
Francis Degache
Author(s):  
Z Rojhani-Shirazi ◽  
Z Amiri ◽  
S Ebrahimi

Background: The maintenance of postural control is a key component in dynamic physical activity, especially during muscle fatigue and against external forces. Despite many studies in this field, there is no consensus regarding the effects of plantar flexor muscles fatigue on postural control during different postural tasks.Objective: To evaluate the effects of plantar flexor muscles fatigue on postural control during quiet stance and external perturbation in healthy subjects.Methods: Twenty four healthy individuals (20-35 years) participated this interventional study. The foot center of pressure data was measured using a single force platform, and then the postural control parameters, including the center of pressure displacement and velocity in the anterior-posterior and medial-lateral direction and also path length calculated under two conditions; quiet and perturbed stance, before and after plantar flexor muscles fatigue.Results: The statistical analysis demonstrated that mean displacement and velocity of the center of pressure in the anterior-posterior direction and also path length increased after the fatigue protocol in the perturbed condition. However, fatigue had no significant effects on postural control parameters in the quiet standing condition.Conclusion: These results indicated that the effects of muscle fatigue on postural control depend on the difficulty of the task and the relevance of proprioceptive information. The postural control system appears to use distinct control strategies in different situations such as quiet and perturbed stance conditions, and these strategies may be differentially altered by fatigue. In conclusion, due to the potential risk of loss of balance, it is important to take the role of plantar flexor muscle fatigue into account during more difficult postural tasks.


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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