Dynamic modeling of SEMG–force relation in the presence of muscle fatigue during isometric contractions

2016 ◽  
Vol 28 ◽  
pp. 41-49 ◽  
Author(s):  
Moein Asefi ◽  
Sahar Moghimi ◽  
Hadi Kalani ◽  
Ali Moghimi
Keyword(s):  
Muscle Fatigue ◽  
Dynamic Modeling ◽  
Isometric Contractions ◽  
Force Relation

sEMG feature analysis on forearm muscle fatigue during isometric contractions

2014 ◽  
Vol 20 (2) ◽  
pp. 139-143 ◽  
Author(s):  
Dong Ming ◽  
Xin Wang ◽  
Rui Xu ◽  
Shuang Qiu ◽  
Xin Zhao ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Feature Analysis ◽  
Isometric Contractions ◽  
Forearm Muscle

scholarly journals Contraction frequency modulates muscle fatigue and the rate of myoglobin desaturation during incremental contractions in humans

2008 ◽  
Vol 33 (5) ◽  
pp. 915-921 ◽  
Author(s):  
Danielle M. Wigmore ◽  
Douglas E. Befroy ◽  
Ian R. Lanza ◽  
Jane A. Kent-Braun
Keyword(s):  
Muscle Fatigue ◽  
Muscle Force ◽  
Force Production ◽  
Metabolic Cost ◽  
Resonance Spectroscopy ◽  
Isometric Contractions ◽  
Metabolic Demand ◽  
Contraction Frequency ◽  
Duty Cycles ◽  
Force Time

The metabolic cost of force production, and therefore the demand for oxygen, increases with intensity and frequency of contraction. This study investigated the interaction between fatigue and oxygenation, as reflected by deoxymyoglobin (dMb), during slow and rapid rhythmic isometric contractions having the same duty cycles and relative force–time integrals (FTIs). We used 1H magnetic resonance spectroscopy and measures of dorsiflexor muscle force to compare dMb and fatigue (fall of maximal voluntary force, MVC) in 11 healthy adults (29 ± 7 y) during 16 min of slow (4 s contraction, 6 s relaxation) and rapid (1.2 s, 1.8 s) incremental (10%–80% MVC) contractions. We tested the hypotheses that (i) the rate of Mb desaturation would be faster in rapid than in slow contractions and (ii) fatigue, Mb desaturation, and the fall in FTI would be greater, and PO2 (oxygen tension) lower, at the end of rapid contractions than at the end of slow contractions. Although dMb increased more quickly during rapid contractions (p = 0.05), it reached a plateau at a similar level in both protocols (~42% max, p = 0.49), likely due to an inability to further increase force production and thus metabolic demand. Despite the similar dMb at the end of both protocols, fatigue was greater in rapid (56.6% ± 2.7% baseline) than in slow (69.5% ± 4.0%, p = 0.01) contractions. These results indicate that human skeletal muscle fatigue during incremental isometric contractions is in part a function of contraction frequency, possibly due to metabolic inhibition of the contractile process.

Length Range, Morphology and Mechanical Behaviour of Rat Gastrocnemius Muscle During Isometric Contraction At the Level of the Muscle and Muscle Tendon Complex

1984 ◽  
Vol 35 (3) ◽  
pp. 505-516 ◽  
Author(s):  
R.D. Woittiez ◽  
P.A. Huijing
Keyword(s):  
Isometric Contraction ◽  
Fibre Length ◽  
Muscle Length ◽  
Muscle Fibres ◽  
Isometric Contractions ◽  
Force Relation ◽  
Length Range ◽  
Equilibrium Length ◽  
Fibre Angle

Fibre length, fibre angle and muscle length were quantified for rat m. gastrocnemius medialis with the muscle passive as well as fully activated during isometric contraction. This was done with the muscle in situ still attached with intact origin and insertion as well as with the calcaneus cut for simultaneous force measurements. Comparison of muscle lengths in maximal plantar and dorsal flexion with the physiological length range of the muscle, as defined by the limits of the length force relation, indicated that approximately the lower 75% of this range may be used between the extreme ankle angles, while the knee is kept at 90° of flexion. It is likely that simultaneous knee extentension would take the muscle through the remainder of its physiological length range. During isometric contractions at the level of the muscle, fibres shorten and fibre angles increase (with values exceeding 12 % and 45 % respectively at short muscle lengths). At short lengths fibre angle may reach values exceeding 40°, thereby creating sizable differences between force exerted by the muscle and that of its fibres. Changes of fibre length and fibre angle increase with decreasing muscle length and are ascribed to compliance effects of the aponeuroses above muscle equilibrium length while below muscle equilibrium length a taking up of slack present in these structures occurs prior to these compliance effects. During isometric contractions at the level of the muscle-tendon complex work will be performed by the muscle on the achilles tendon. This work was estimated from tendon length-force characteristics. Its peak value does not exceed 1.35 mJ for any of the muscles at anv length, which is small ( < 2 % ) relative to estimated total energv expenditure of the isometric contractions.

Nonlinear Control of NMES: Incorporating Fatigue and Calcium Dynamics

2009 ◽  
Author(s):  
N. Sharma ◽  
P. M. Patre ◽  
C. M. Gregory ◽  
W. E. Dixon
Keyword(s):  
Muscle Fatigue ◽  
Neuromuscular Electrical Stimulation ◽  
Isometric Contractions ◽  
Calcium Dynamics ◽  
Nonlinear Controller ◽  
Promising Technique ◽  
Current Effort ◽  
Model Mismatch ◽  
Fatigue Model ◽  
Femoris Muscle

Neuromuscular electrical stimulation (NMES) is a promising technique that has the potential to restore functional tasks in persons with movement disorders. Clinical and commercial NMES products exist for this purpose, but a pervasive problem with current technology is that overstimulation of the muscle (among other factors) leads to muscle fatigue. The objective of the current effort is to develop a NMES controller that incorporates the effects of muscle fatigue through an uncertain function of the calcium dynamics. A neural network-based estimate of the fatigue model mismatch is incorporated in a nonlinear controller through a backstepping based method to control the human quadriceps femoris muscle undergoing non-isometric contractions. The developed controller is proven to yield uniformly ultimately bounded stability for an uncertain nonlinear muscle model in the presence of bounded nonlinear disturbances (e.g., spasticity, delays, changing load dynamics).

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