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Simulating Motor Units for Fatigue Arm Muscles in Digital Humans
Technical Paper
2006-01-2348
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
This paper attempts to simulate fatigue in human arm muscles by modeling their basic building blocks - the motor units. Human muscles can be considered to consist of 3 types of motor units: slow-twitch, fatigue-resistant (S); fast-twitch, fatigue-resistant (FR); and fast-twitch, fatigable (FF) motor units. The S units typically generate the smallest forces that can be maintained almost indefinitely. FR units are capable of generating higher forces more rapidly, but can still maintain force for some time and hence, are generally considered as fatigue-resistant. The FF units are able to generate the highest force, but can only sustain it for a short period of time, making them fatigue-susceptible. Whole muscle force and force fatigue has been modeled by a system of coupled differential equations first proposed by Wexler, et al in 1998, and have been refined by Ding and colleagues since then. These equations are theorized to represent the interaction of the calcium kinetics in the sarcoplasmic reticulum with a mechanical force generator and a coefficient-relaxor in order to capture the decline in the muscle force over time. The decline in the force generation with continued activation (e.g. fatigue) may be due to a complex combination of factors, including a decrease in the sensitivity of the troponin complex to calcium ions. This paper extends the basic whole muscle fatigue model proposed by Ding and colleagues to individual motor units, enabling separate decay coefficients for each motor unit. This approach may make generalizing the muscle model to a variety of muscles possible, versus the current methodology of parameterizing the model to each individual. The model represents activation of the 3 motor units, grouped in bundles of varying proportions that constitute a particular muscle in the human body, to produce a net force for each muscle. This analysis involves the determination of force-time histories of the three elbow flexor muscles, biceps brachii, brachialis and brachioradialis, during tasks involving torque generation. Qualitative comparisons to human torque generation demonstrate that overall elbow flexion torque predictions decay appropriately using this new modeling methodology.
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Citation
Yang, Q., Han, R., and Law, L., "Simulating Motor Units for Fatigue Arm Muscles in Digital Humans," SAE Technical Paper 2006-01-2348, 2006, https://doi.org/10.4271/2006-01-2348.Also In
References
- Amis A. A. Dowson D. Wright. a. V., 1979 Muscle strengths and musculo-skeletal geometry of the upper limb. Engineering in Medicine 8 1 41 48
- Wexler Anthony S. Ding Jun Binder-Macleod. S.A. 1997 A Mathematical Model that Predicts Skeletal Muscle Force. IEEE Transactions on Biomedical Engineering 44 5 337 348
- Hamilton Antonia F. de C. Jones Kelvin E. Wolpert. D.M. 2004 The scaling of motor noise with muscle strength and motor unit number in humans. Experimental Brain Research 157 417 430
- Bhatti M.A. Han. R.P.S. Vignes. R. Muscle Forces and Fatigue in a Digital Human Environment 2005 Digital Human Modeling for Design and Engineering Conference University of Iowa IA 52242, USA 2005
- Klein Cliff S. Marsh Greg D. Petrella Robert J. Rice. C.L. 2003 Muscle Fiber Number in the Biceps Brachii Muscle of Young and Old Men. Muscle Nerve 28 62 68
- Enoka. R.M. Neuromechanical basis of kinesiology 2 Braun-Brumfield 1994
- Hill A.V. 1938 The heat of shortening and the dynamic constants of muscle. Proceeding of the Royal Society of London B. 126 136 195
- Huxley A.F. Muscle Structure and theories of contraction Biophysics and Biophysical Chemistry 7 1957 255 318
- Ding Jun Binder-Macleod Stuart A. Wexler. A.S. 1998 Two-step, predictive, isometric force model tested on data from human and rat muscles. Journal of Applied. Physiology 85 6 2176 2189
- Ding Jun Wexler Anthony S. Binder-Macleod. S.A. (2000.-a) A predictive model of fatigue in human skeletal muscles. Journal of Applied. Physiology 89 1322 1332
- Ding Jun Wexler Anthony S. Binder-Macleod. S.A. 2000 Development of a mathematical model that predicts optimal muscle activation patterns by using brief trains. Journal of Applied Physiology 88 917 925
- Clarkson Priscilla M. Kroll Walter Melchionda. A.M. 1982 Isokinetic Strength, Endurance, and Fiber Type Composition in Elite American Paddlers. European Journal of Applied Physiology 48 67 76
- Edgerton V.R. Apor P. Roy. R.R. 1990 Specific tension of human elbow flexor muscles. Acta Physiologica Hungarica 75 3 205 216
- Murray Wendy M. Buchanan Thomas S. Delp S. L. 2000 The isometric functional capacity of muscles that cross the elbow. Journal of Biomechanics 33 943 952
- Zahalak G.I. Ma S.P. 1990 Muscle activation and contraction: Constitutive relations based directly on cross-bridge kinetics. Journal of Biomechanical Engineering 112 52 62
- Zajac F.E. Topp E.L. Stevenson P.J. A dimensionless musculotendon model. American Conference of IEEE in Engineering Medical Biology Society. Dallas-Ft Worth, TX 1986 601 604