Skip to main content
SpringerLink
Log in

Influence of motor unit properties on the size of the simulated evoked surface EMG potential

  • Research Article
  • Published:
Experimental Brain Research Aims and scope Submit manuscript

Abstract

The purpose of the study was to quantify the influence of selected motor unit properties on the simulated amplitude and area of evoked muscle potentials detected at the skin surface. The study was restricted to a motor unit population simulating a hand muscle whose potentials were recorded on the skin over the muscle. Peak-to-peak amplitude and area of the evoked potential were calculated from the summed motor unit potentials and compared across conditions that simulated variation in different motor unit properties. The simulations involved varying the number of activated motor units, muscle fiber conduction velocities, axonal conduction velocities, neuronal activation times, the shape of the intracellular action potential, and recording configurations commonly used over hand muscles. The results obtained for the default condition simulated in this study indicated that ~7% of the motor unit potentials were responsible for 50% of the size of the evoked potential. Variation in the amplitude and area of the evoked muscle potential was directly related to the number of active motor units only when the stimulus activated motor units randomly, and not when activation was based on a parameter such as motor unit size. Independent adjustments in motor unit properties had variable effects on the size of the evoked muscle potential, including when the stimulus activated only a subpopulation of motor units. These results provide reference information that can be used to assist in the interpretation of experimentally observed changes in the size of evoked muscle potentials.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6

Similar content being viewed by others

Abbreviations

MEP:

motor evoked potentials

M-wave:

compound muscle action potential

au:

arbitrary unit

MU:

motor unit

References

  • Andersen B, Westlund B, Krarup C (2003) Failure of activation of spinal motoneurones after muscle fatigue in healthy subjects studied by transcranial magnetic stimulation. J Physiol 551:345–356

    Article  PubMed  CAS  Google Scholar 

  • Andreassen S, Arendt-Nielsen L (1987) Muscle fibre conduction velocity in motor units of the human anterior tibial muscle: a new size principle parameter. J Physiol 391:561–571

    PubMed  CAS  Google Scholar 

  • Arendt-Nielsen L, Zwarts M (1989) Measurement of muscle fiber conduction velocity in humans: techniques and applications. J Clin Neurophysiol 6:173–190

    PubMed  CAS  Google Scholar 

  • Armstrong JB, Rose PK, Vanner S, Bakker GJ, Richmond FJ (1988) Compartmentalization of motor units in the cat neck muscle, biventer cervicis. J Neurophysiol 60:30–45

    PubMed  CAS  Google Scholar 

  • Bellemare F, Garzaniti N (1988) Failure of neuromuscular propagation during human maximal voluntary contraction. J Appl Physiol 64:1084–1093

    PubMed  CAS  Google Scholar 

  • Bigland-Ritchie B, Kukulka CG, Lippold OC, Woods JJ (1982) The absence of neuromuscular transmission failure in sustained maximal voluntary contractions. J Physiol 330:265–278

    PubMed  CAS  Google Scholar 

  • Blok JH, Stegeman DF, van Oosterom A (2002) Three-layer volume conductor model and software package for applications in surface electromyography. Ann Biomed Engin 30:566–577

    Article  CAS  Google Scholar 

  • Bodine SC, Garfinkel A, Roy RR, Edgerton VR (1988) Spatial distribution of motor unit fibers in the cat soleus and tibialis anterior muscles: local interactions. J Neurosci 8:2142–2152

    PubMed  CAS  Google Scholar 

  • Bodine SC, Roy RR, Eldred E, Edgerton VR (1987) Maximal force as a function of anatomical features of motor units in the cat tibialis anterior. J Neurophysiol 57:1730–1745

    PubMed  CAS  Google Scholar 

  • Boniface SJ, Mills KR, Schubert M (1991) Responses of single spinal motoneurons to magnetic brain stimulation in healthy subjects and patients with multiple sclerosis. Brain 114(Pt 1B):643–662

    PubMed  Google Scholar 

  • Buchthal F, Erminio F, Rosenfalck P (1959) Motor unit territory in different human muscles. Acta Physiol Scand 45:72–87

    PubMed  CAS  Google Scholar 

  • Burke D, Kiernan MC, Bostock H (2001) Excitability of human axons. Clin Neurophysiol 112:1575–1585

    Article  PubMed  CAS  Google Scholar 

  • Butler JE, Taylor JL, Gandevia SC (2003) Responses of human motoneurons to corticospinal stimulation during maximal voluntary contractions and ischemia. J Neurosci 23:10224–10230

    PubMed  CAS  Google Scholar 

  • Carroll TJ, Riek S, Carson RG (2002) The sites of neural adaptation induced by resistance training in humans. J Physiol 544:641–652

    Article  PubMed  CAS  Google Scholar 

  • Chisari C, Simonella C, Rossi B (2001) A surface EMG analysis of sarcolemma excitability alteration and myofibre degeneration in Steinert disease. Clin Neurophysiol 112:1925–1930

    Article  PubMed  CAS  Google Scholar 

  • Crone C, Johnsen LL, Hultborn H, Ørsnes GB (1999) Amplitude of the maximum motor response (Mmax) in human muscles typically decreases during the course of an experiment. Exp Brain Res 124:265–270

    Article  PubMed  CAS  Google Scholar 

  • Cupido CM, Galea V, McComas AJ (1996) Potentiation and depression of the M wave in human biceps brachii. J Physiol 491(Pt 2):541–550

    PubMed  CAS  Google Scholar 

  • Dalpozzo F, Gerard P, De Pasqua V, Wang F, Maertens de Noordhout A (2002) Single motor axon conduction velocities of human upper and lower limb motor units. A study with transcranial electrical stimulation. Clin Neurophysiol 113:284–291

    Article  PubMed  Google Scholar 

  • Datta AK, Harrison LM, Stephens JA (1989) Task-dependent changes in the size of response to magnetic brain stimulation in human first dorsal interosseous muscle. J Physiol 418:13–23

    PubMed  CAS  Google Scholar 

  • Day BL, Dressler D, Maertens de Noordhout A, Marsden CD, Nakashima K, Rothwell JC, Thompson PD (1989) Electric and magnetic stimulation of human motor cortex: surface EMG and single motor unit responses. J Physiol 412:449–473

    PubMed  CAS  Google Scholar 

  • Day BL, Rothwell JC, Thompson PD, Dick JP, Cowan JM, Berardelli A, Marsden CD (1987) Motor cortex stimulation in intact man. 2. Multiple descending volleys. Brain 110(Pt 5):1191–1209

    Google Scholar 

  • Dengler R, Stein RB, Thomas CK (1988) Axonal conduction velocity and force of single human motor units. Muscle Nerve 11:136–145

    Article  PubMed  CAS  Google Scholar 

  • Dennett X, Fry HJ (1988) Overuse syndrome: a muscle biopsy study. Lancet 331:905–908

    Article  Google Scholar 

  • Di Lazzaro V, Oliviero A, Pilato F, Saturno E, Dileone M, Mazzone P, Insola A, Tonali PA, Rothwell JC (2004) The physiological basis of transcranial motor cortex stimulation in conscious humans. Clin Neurophysiol 115:255–266

    Article  PubMed  CAS  Google Scholar 

  • Dimitrova N, Dimitrov G (2002) Amplitude-related characteristics of motor unit and M-wave potentials during fatigue. A simulation study using literature data on intracellular potential changes found in vitro. J Electromyogr Kinesiol 12:339–349

    Article  PubMed  CAS  Google Scholar 

  • Duchateau J, Hainaut K (1985) Electrical and mechanical failures during sustained and intermittent contractions in humans. J Appl Physiol 58:942–947

    PubMed  CAS  Google Scholar 

  • Elek JM, Kossev A, Dengler R, Schubert M, Wohlfahrt K, Wolf W (1992) Parameters of human motor unit twitches obtained by intramuscular microstimulation. Neuromuscul Disord 2:261–267

    PubMed  CAS  Google Scholar 

  • Enoka RM (2002) Activation order of motor axons in electrically evoked contractions. Muscle Nerve 25:763–764

    Article  PubMed  Google Scholar 

  • Enoka RM, Fuglevand AJ (2001) Motor unit physiology: some unresolved issues. Muscle Nerve 24:4–17

    Article  PubMed  CAS  Google Scholar 

  • Enoka RM, Trayanova N, Laouris Y, Bevan L, Reinking RM, Stuart DG (1992) Fatigue-related changes in motor unit action potentials of adult cats. Muscle Nerve 15:138–150

    Article  PubMed  CAS  Google Scholar 

  • Farina D, Arendt-Nielsen L, Merletti R, Graven-Nielsen T (2002) Assessment of single motor unit conduction velocity during sustained contractions of the tibialis anterior muscle with advanced spike triggered averaging. J Neurosci Methods 115:1–12

    PubMed  Google Scholar 

  • Farina D, Blanchietti A, Pozzo M, Merletti R (2004a) M-wave properties during progressive motor unit activation by transcutaneous stimulation. J Appl Physiol 97:545–555

    Article  PubMed  Google Scholar 

  • Farina D, Fortunato E, Merletti R (2000) Noninvasive estimation of motor unit conduction velocity distribution using linear electrode arrays. IEEE Trans Biomed Eng 47:380–388

    Article  PubMed  CAS  Google Scholar 

  • Farina D, Merletti R (2001) A novel approach for precise simulation of the EMG signal detected by surface electrodes. IEEE Trans Biomed Engin 48:637–646

    Article  CAS  Google Scholar 

  • Farina D, Merletti R, Enoka RM (2004b) The extraction of neural strategies from the surface EMG. J Appl Physiol 96:1486–1495

    Article  PubMed  Google Scholar 

  • Flament D, Goldsmith P, Buckley CJ, Lemon RN (1993) Task dependence of responses in first dorsal interosseous muscle to magnetic brain stimulation in man. J Physiol 464:361–378

    PubMed  CAS  Google Scholar 

  • Fuglevand AJ (1995) The role of the sarcolemma action potential in fatigue. In: Gandevia SC, Enoka RM, McComas AJ, Stuart DG, Thomas CK (eds) Fatigue: neural and muscular mechanisms, vol 384. Plenum Press, New York, pp 101–108

    Google Scholar 

  • Fuglevand AJ, Winter DA, Patla AE (1993a) Models of recruitment and rate coding organization in motor-unit pools. J Neurophysiol 70:2470–2488

    PubMed  CAS  Google Scholar 

  • Fuglevand AJ, Winter DA, Patla AE, Stashuk D (1992) Detection of motor unit action potentials with surface electrodes: influence of electrode size and spacing. Biol Cybern 67:143–153

    Article  PubMed  CAS  Google Scholar 

  • Fuglevand AJ, Zackowski KM, Huey KA, Enoka RM (1993b) Impairment of neuromuscular propagation during human fatiguing contractions at submaximal forces. J Physiol 460:549–572

    PubMed  CAS  Google Scholar 

  • Gandevia SC (2001) Spinal and supraspinal factors in human muscle fatigue. Physiol Rev 81:1725–1789

    PubMed  CAS  Google Scholar 

  • Gardiner PF, Olha AE (1987) Contractile and electromyographic characteristics of rat plantaris motor unit types during fatigue in situ. J Physiol 385:13–34

    PubMed  CAS  Google Scholar 

  • Gatev P, Dimitrov GV, Gydikov A, Gerilovsky L (1981) Effect of ischaemia on the potentials of human single muscle fibres. Acta Physiol Pharmacol Bulg 7:3–12

    PubMed  CAS  Google Scholar 

  • Gydikov A, Kosarov D, Dimitrov GV (1979) Length of the summated depolarized area and duration of the depolarizing and repolarizing processes in the motor unit under different conditions. Electromyogr Clin Neurophysiol 19:229–248

    PubMed  CAS  Google Scholar 

  • Harrison AP, Flatman JA (1999) Measurement of force and both surface and deep M wave properties in isolated rat soleus muscles. J Physiol 277:R1646–1653

    CAS  Google Scholar 

  • Henneman E (1957) Relation between size of neurons and their susceptibility to discharge. Science 126:1345–1347

    PubMed  CAS  Google Scholar 

  • Hess CW, Mills KR, Murray NM (1987) Responses in small hand muscles from magnetic stimulation of the human brain. J Physiol 388:397–419

    PubMed  CAS  Google Scholar 

  • Hoppeler H, Luthi P, Claassen H, Weibel ER, Howald H (1973) The ultrastructure of the normal human skeletal muscle. A morphometric analysis on untrained men, women and well-trained orienteers. Pflugers Arch 344:217–232

    Article  PubMed  CAS  Google Scholar 

  • Johnson MA, Polgar J, Weightman D, Appleton D (1973) Data on the distribution of fibre types in thirty-six human muscles. An autopsy study. J Neurol Sci 18:111–129

    Article  PubMed  CAS  Google Scholar 

  • Kalmar JM, Cafarelli E (2004) Central fatigue and transcranial magnetic stimulation: effect of caffeine and the confound of peripheral transmission failure. J Neurosci Methods 138:15–26

    Article  PubMed  CAS  Google Scholar 

  • Kanda K, Hashizume K (1992) Factors causing difference in force output among motor units in the rat medial gastrocnemius muscle. J Physiol 448:677–695

    PubMed  CAS  Google Scholar 

  • Keen DA, Yue GH, Enoka RM (1994) Training-related enhancement in the control of motor output in elderly humans. J Appl Physiol 77:2648–2658

    PubMed  CAS  Google Scholar 

  • Keenan KG, Farina D, Maluf KS, Merletti R, Enoka RM (2005) Influence of amplitude cancellation on the simulated electromyogram. J Appl Physiol 98:120–131

    Article  PubMed  Google Scholar 

  • Keenan KG, Farina D, Merletti R, Enoka RM (2004) M-wave size is influenced by the range of conduction velocities and the timing of motor unit action potentials. In: Roy SH, Bonato P, Meyer J (eds) Proceedings of the 15th ISEK Congress, Boston, p 174

  • Kernell D (1992) Organized variability in the neuromuscular system: a survey of task-related adaptations. Arch Ital Biol 130:19–66

    PubMed  CAS  Google Scholar 

  • Kernell D, Eerbeek O, Verhey BA (1983) Motor unit categorization on basis of contractile properties: an experimental analysis of the composition of the cat’s m. peroneus longus. Exp Brain Res 50:211–219

    CAS  Google Scholar 

  • Kiernan MC, Lin CS, Burke D (2004) Differences in activity-dependent hyperpolarization in human sensory and motor axons. J Physiol 558:341–349

    Article  PubMed  CAS  Google Scholar 

  • Klass M, Guissard N, Duchateau J (2004) Limiting mechanisms of force production after repetitive dynamic contractions in human triceps surae. J Appl Physiol 96:1516–1521

    Article  PubMed  CAS  Google Scholar 

  • Lange F, Van Weerden TW, Van Der Hoeven JH (2002) A new surface electromyography analysis method to determine spread of muscle fiber conduction velocities. J Appl Physiol 93:759–764

    PubMed  Google Scholar 

  • Lee RG, Ashby P, White DG, Aguayo AJ (1975) Analysis of motor conduction velocity in the human median nerve by computer simulation of compound muscle action potentials. Electroencephalogr Clin Neurophysiol 39:225–237

    Article  PubMed  CAS  Google Scholar 

  • Lindstrom L, Magnusson R (1977) Interpretation of myoelectric power spectra: a model and its application. Proc IEEE 65:653–662

    Article  Google Scholar 

  • Magistris MR, Rösler KM, Truffert A, Myers JP (1998) Transcranial stimulation excites virtually all motor neurons supplying the target muscle. A demonstration and a method improving the study of motor evoked potentials. Brain 121(Pt 3):437–450

    Article  PubMed  Google Scholar 

  • McGill KC, Lateva ZC (1999) The contribution of the interosseous muscles to the hypothenar compound muscle action potential. Muscle Nerve 22:6–15

    Article  PubMed  CAS  Google Scholar 

  • Metzger JM, Fitts RH (1986) Fatigue from high- and low-frequency muscle stimulation: role of sarcolemma action potentials. Exp Neurol 93:320–333

    Article  PubMed  CAS  Google Scholar 

  • Millet GY, Lepers R (2004) Alterations of neuromuscular function after prolonged running, cycling and skiing exercises. Sports Med 34:105–116

    Article  PubMed  Google Scholar 

  • Milner-Brown HS, Stein RB (1975) The relation between the surface electromyogram and muscular force. J Physiol 246:549–569

    PubMed  CAS  Google Scholar 

  • Milner-Brown HS, Stein RB, Yemm R (1973) The orderly recruitment of human motor units during voluntary isometric contractions. J Physiol 230:359–370

    PubMed  CAS  Google Scholar 

  • Nordlund MM, Thorstensson A, Cresswell AG (2004) Central and peripheral contributions to fatigue in relation to level of activation during repeated maximal voluntary isometric plantar flexions. J Appl Physiol 96:218–225

    Article  PubMed  Google Scholar 

  • Olivier E, Bawa P, Lemon RN (1995) Excitability of human upper limb motoneurones during rhythmic discharge tested with transcranial magnetic stimulation. J Physiol 485(Pt 1):257–269

    PubMed  CAS  Google Scholar 

  • Pierrot-Deseilligny E, Mazevet D (2000) The monosynaptic reflex: a tool to investigate motor control in humans. Interest and limits. Neurophysiol Clin 30:67–80

    PubMed  CAS  Google Scholar 

  • Radicheva N, Gerilovsky L, Gydikov A (1986) Changes in the muscle fibre extracellular action potentials in long-lasting (fatiguing) activity. Eur J Appl Physiol Occup Physiol 55:545–552

    PubMed  CAS  Google Scholar 

  • Rhee EK, England JD, Sumner AJ (1990) A computer simulation of conduction block: effects produced by actual block versus interphase cancellation. Ann Neurol 28:146–156

    Article  PubMed  CAS  Google Scholar 

  • Roeleveld K, Blok JH, Stegeman DF, van Oosterom A (1997a) Volume conduction models for surface EMG; confrontation with measurements. J Electromyogr Kinesiol 7:221–232

    Article  PubMed  Google Scholar 

  • Roeleveld K, Stegeman DF, Vingerhoets HM, Van Oosterom A (1997b) Motor unit potential contribution to surface electromyography. Acta Physiol Scand 160:175–183

    Article  PubMed  CAS  Google Scholar 

  • Rosenfalck P (1969) Intra- and extracellular potential fields of active nerve and muscle fibers. Acta Physiol Scand Suppl 47:239–246

    Google Scholar 

  • Rothwell JC (1997) Techniques and mechanisms of action of transcranial stimulation of the human motor cortex. J Neurosci Methods 74:113–122

    Article  PubMed  CAS  Google Scholar 

  • Rothwell JC, Thompson PD, Day BL, Dick JP, Kachi T, Cowan JM, Marsden CD (1987) Motor cortex stimulation in intact man 1 General characteristics of EMG responses in different muscles. Brain 110(Pt 5):1173–1190

    PubMed  Google Scholar 

  • Saitou K, Masuda T, Michikami D, Kojima R, Okada M (2000) Innervation zones of the upper and lower limb muscles estimated by using multichannel surface EMG. J Hum Ergol (Tokyo) 29:35–52

    CAS  Google Scholar 

  • Scaglioni G, Narici MV, Maffiuletti NA, Pensini M, Martin A (2003) Effect of ageing on the electrical and mechanical properties of human soleus motor units activated by the H reflex and M wave. J Physiol 548:649–661

    Article  PubMed  CAS  Google Scholar 

  • Schieppati M (1987) The Hoffmann reflex: a means of assessing spinal reflex excitability and its descending control in man. Prog Neurobiol 28:345–376

    Article  PubMed  CAS  Google Scholar 

  • Schieppati M, Trompetto C, Abbruzzese G (1996) Selective facilitation of responses to cortical stimulation of proximal and distal arm muscles by precision tasks in man. J Physiol 491(Pt 2):551–562

    PubMed  CAS  Google Scholar 

  • Semmler JG, Türker KS (1994) Compound group I excitatory input is differentially distributed to motoneurons of the human tibialis anterior. Neurosci Lett 178:206–210

    Article  PubMed  CAS  Google Scholar 

  • Sieck GC, Prakash YS (1995) Fatigue at the neuromuscular junction. In: Gandevia SC, Enoka RM, McComas AJ, Stuart DG, Thomas CK (eds) Fatigue: neural and muscular mechanisms, vol 384. Plenum Press, New York, pp 101–108

    Google Scholar 

  • Stålberg E (1966) Propagation velocity in human muscle fibers in situ. Acta Physiol Scand Suppl 287:1–112

    PubMed  Google Scholar 

  • Stålberg E, Antoni L (1980) Electrophysiological cross section of the motor unit. J Neurol Neurosurg Psychiatry 43:469–474

    PubMed  Google Scholar 

  • Stålberg E, Karlsson L (2001) The motor nerve simulator. Clin Neurophysiol 112:2118–2132

    Article  PubMed  Google Scholar 

  • Stein RB, Yang JF (1990) Methods for estimating the number of motor units in human muscles. Ann Neurol 28:487–495

    Article  PubMed  CAS  Google Scholar 

  • Taborikova H (1968) Changes in motoneurone excitability produced by sudden ankle movement. Electroencephalogr Clin Neurophysiol 25:408

    PubMed  CAS  Google Scholar 

  • Taylor JL, Butler JE, Allen GM, Gandevia SC (1996) Changes in motor cortical excitability during human muscle fatigue. J Physiol 490(Pt 2):519–528

    PubMed  CAS  Google Scholar 

  • Taylor JL, Gandevia SC (2001) Transcranial magnetic stimulation and human muscle fatigue. Muscle Nerve 24:18–29

    Article  PubMed  CAS  Google Scholar 

  • Thomas CK, Nelson G, Than L, Zijdewind I (2002) Motor unit activation order during electrically evoked contractions of paralyzed or partially paralyzed muscles. Muscle Nerve 25:797–804

    Article  PubMed  Google Scholar 

  • Thomas CK, Ross BH, Stein RB (1986) Motor-unit recruitment in human first dorsal interosseous muscle for static contractions in three different directions. J Neurophysiol 55:1017–1029

    PubMed  CAS  Google Scholar 

  • Thomas CK, Woods JJ, Bigland-Ritchie B (1989) Impulse propagation and muscle activation in long maximal voluntary contractions. J Appl Physiol 67:1835–1842

    PubMed  CAS  Google Scholar 

  • Van Cutsem M, Feiereisen P, Duchateau J, Hainaut K (1997) Mechanical properties and behaviour of motor units in the tibialis anterior during voluntary contractions. Can J Appl Physiol 22:585–597

    PubMed  Google Scholar 

  • van Dijk JG, Tjon-a-Tsien A, van der Kamp W (1995) CMAP variability as a function of electrode site and size. Muscle Nerve 18:68–73

    Article  PubMed  Google Scholar 

  • Yao W, Fuglevand AJ, Enoka RM (2000) Motor-unit synchronization increases EMG amplitude and decreases force steadiness of simulated contractions. J Neurophysiol 83:441–452

    PubMed  CAS  Google Scholar 

  • Zehr PE (2002) Considerations for use of the Hoffmann reflex in exercise studies. Eur J Appl Physiol 86:455–468

    Article  PubMed  Google Scholar 

  • Zijdewind I, de Groot MC, Kernell D (1998) Task-related variations in motoneuronal drive to a human intrinsic hand muscle. Neurosci Lett 242:139–142

    Article  PubMed  CAS  Google Scholar 

  • Zijdewind I, Kernell D (1994) Index finger position and force of the human first dorsal interosseus and its ulnar nerve antagonist. J Appl Physiol 77:987–997

    PubMed  CAS  Google Scholar 

  • Zijdewind I, Zwarts MJ, Kernell D (1999) Fatigue-associated changes in the electromyogram of the human first dorsal interosseous muscle. Muscle Nerve 22:1432–1436

    Article  PubMed  CAS  Google Scholar 

  • Zijdewind I, Zwarts MJ, Kernell D (2000) Potentiating and fatiguing cortical reactions in a voluntary fatigue test of a human hand muscle. Exp Brain Res 130:529–532

    Article  PubMed  CAS  Google Scholar 

  • Zwarts MJ, Arendt-Nielsen L (1988) The influence of force and circulation on average muscle fibre conduction velocity during local muscle fatigue. Eur J Appl Physiol Occup Physiol 58:278–283

    Article  PubMed  CAS  Google Scholar 

  • Zwarts MJ, Stegeman DF (2003) Multichannel surface EMG: basic aspects and clinical utility. Muscle Nerve 28:1–17

    Article  PubMed  Google Scholar 

Download references

Acknowledgements

The authors thank Dr Jacques Duchateau for comments on an earlier version of the manuscript and Dr Nonna Dimitrova for assistance with the analytical descriptions of the intracellular action potentials. The research was supported by the awards from NINDS (NS42734) and NIA (AG09000) to RME.

Author information

Authors and Affiliations

  1. Department of Integrative Physiology, University of Colorado at Boulder , Boulder, CO, 80309, USA

    Kevin G. Keenan & Roger M. Enoka

  2. Department of Health Science and Technology, Center for Sensory-Motor Interaction (SMI), Aalborg University, Aalborg, Denmark

    Dario Farina

  3. Dipartimento di Elettronica Laboratorio di Ingegneria del Sistema Neuromuscolare (LISiN), Politecnico di Torino, Torino, Italy

    Roberto Merletti

Authors
  1. Kevin G. Keenan
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Dario Farina
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Roberto Merletti
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Roger M. Enoka
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Roger M. Enoka.

Additional information

Wilson

Rights and permissions

Reprints and permissions

About this article

Cite this article

Keenan, K.G., Farina, D., Merletti, R. et al. Influence of motor unit properties on the size of the simulated evoked surface EMG potential. Exp Brain Res 169, 37–49 (2006). https://doi.org/10.1007/s00221-005-0126-7

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00221-005-0126-7

Keywords

Search

Navigation