Skip to main content
Log in

Impedance is modulated to meet accuracy demands during goal-directed arm movements

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

Abstract

The neuromuscular system is inherently noisy and joint impedance may serve to filter this noise. In the present experiment, we investigated whether individuals modulate joint impedance to meet spatial accuracy demands. Twelve subjects were instructed to make rapid, time constrained, elbow extensions to three differently sized targets. Some trials (20 out of 140 for each target, randomly assigned) were perturbed mechanically at 75% of movement amplitude. Inertia, damping and stiffness were estimated from the torque and angle deviation signal using a forward simulation and optimization routine. Increases in endpoint accuracy were not always reflected in a decrease in trajectory variability. Only in the final quarter of the trajectory the variability decreased as target width decreased. Stiffness estimates increased significantly with accuracy constraints. Damping estimates only increased for perturbations that were initially directed against the movement direction. We concluded that joint impedance modulation is one of the strategies used by the neuromuscular system to generate accurate movements, at least during the final part of the movement.

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

Access this article

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
Fig. 7

Similar content being viewed by others

Notes

  1. Throughout this paper impedance refers to the combined effect of stiffness and damping. Otherwise stiffness \( (dM/d\varphi ) \) or damping \( (dM/d\ifmmode\expandafter\dot\else\expandafter\.\fi{\varphi }) \) are mentioned explicitly.

References

  • Bennett DJ (1993) Torques generated at the human elbow joint in response to constant position errors imposed during voluntary movements. Exp Brain Res 95:488–498

    PubMed  CAS  Google Scholar 

  • Bennett DJ (1994) Stretch reflex responses in the human elbow joint during a voluntary movement. J Physiol 474:339–351

    PubMed  CAS  Google Scholar 

  • Bennett DJ, Hollerbach JM, Xu Y, Hunter IW (1992) Time-varying stiffness of human elbow joint during cyclic voluntary movement. Exp Brain Res 88:433–442

    Article  PubMed  CAS  Google Scholar 

  • Burdet E, Osu R, Franklin DW, Milner TE, Kawato M (2001) The central nervous system stabilizes unstable dynamics by learning optimal impedance. Nature 414:446–449

    Article  PubMed  CAS  Google Scholar 

  • Burdet E, Osu R, Franklin DW, Yoshioka T, Milner TE, Kawato M (2000) A method for measuring endpoint stiffness during multi-joint arm movements. J Biomech 33:1705–1709

    Article  PubMed  CAS  Google Scholar 

  • Christou EA, Grossman M, Carlton LG (2002) Modeling variability of force during isometric contractions of the quadriceps femoris. J Mot Behav 34:67–81

    Article  PubMed  Google Scholar 

  • Elliott D, Helsen WF, Chua R (2001) A century later: Woodworth’s (1899) two-component model of goal-directed aiming. Psychol Bull 127:342–357

    Article  PubMed  CAS  Google Scholar 

  • Fitts PM (1954) The information capacity of the human motor system in controlling the amplitude of movement. J Exp Psychol 47:381–391

    Article  PubMed  CAS  Google Scholar 

  • Franklin DW, Osu R, Burdet E, Kawato M, Milner TE (2003) Adaptation to stable and unstable dynamics achieved by combined impedance control and inverse dynamics model. J Neurophysiol 90:3270–3282

    Article  PubMed  Google Scholar 

  • Goffe W, Ferrier G, Rogers J (1994) Global optimization of statistical functions with simulated annealing. J Econom 60:65–99

    Article  Google Scholar 

  • Gribble PL, Mullin LI, Cothros N, Mattar A (2003) Role of cocontraction in arm movement accuracy. J Neurophysiol 89:2396–2405

    Article  PubMed  Google Scholar 

  • Hajian AZ, Howe RD (1997) Identification of the mechanical impedance at the human finger tip. J Biomech Eng 119:109–114

    Article  PubMed  CAS  Google Scholar 

  • Harris CM, Wolpert DM (1998) Signal-dependent noise determines motor planning. Nature 394:780–784

    Article  PubMed  CAS  Google Scholar 

  • Jones KE, De AF, Hamilton C, Wolpert DM (2002) Sources of signal-dependent noise during isometric force production. J Neurophysiol 88:1533–1544

    Article  PubMed  Google Scholar 

  • Kalveram KT, Schinauer T, Beirle S, Richter S, Jansen-Osmann P (2005) Threading neural feedforward into a mechanical spring: how biology exploits physics in limb control. Biol Cybern 92:229–240

    Article  PubMed  Google Scholar 

  • Kang N, Shinohara M, Zatsiorsky VM, Latash ML (2004) Learning multi-finger synergies: an uncontrolled manifold analysis. Exp Brain Res 157:336–350

    Article  PubMed  Google Scholar 

  • Kearney RE, Stein RB, Parameswaran L (1997) Identification of intrinsic and reflex contributions to human ankle stiffness dynamics. IEEE Trans Biomed Eng 44:493–504

    Article  PubMed  CAS  Google Scholar 

  • Laursen B, Jensen BR, Sjogaard G (1998) Effect of speed and precision demands on human shoulder muscle electromyography during a repetitive task. Eur J Appl Physiol Occup Physiol 78:544–548

    Article  PubMed  CAS  Google Scholar 

  • Milner TE, Cloutier C (1998) Damping of the wrist joint during voluntary movement. Exp Brain Res 122:309–317

    Article  PubMed  CAS  Google Scholar 

  • Müller H, Sternad D (2004) Decomposition of variability in the execution of goal-oriented tasks: three components of skill improvement. J Exp Psychol Hum Percept Perform 30:212–233

    Article  PubMed  Google Scholar 

  • Osu R, Franklin DW, Kato H, Gomi H, Domen K, Yoshioka T, Kawato M (2002) Short- and long-term changes in joint co-contraction associated with motor learning as revealed from surface EMG. J Neurophysiol 88:991–1004

    PubMed  Google Scholar 

  • Osu R, Kamimura N, Iwasaki H, Nakano E, Harris CM, Wada Y, Kawato M (2004) Optimal impedance control for task achievement in the presence of signal-dependent noise. J Neurophysiol 92:1199–1215

    Article  PubMed  Google Scholar 

  • Plamondon R, Alimi AM (1997) Speed/accuracy trade-offs in target-directed movements. Behav Brain Sci 20:279–303; Discussion 303–249

    Google Scholar 

  • Popescu F, Hidler JM, Rymer WZ (2003) Elbow impedance during goal-directed movements. Exp Brain Res 152:17–28

    Article  PubMed  Google Scholar 

  • Sandfeld J, Jensen BR (2005) Effect of computer mouse gain and visual demand on mouse clicking performance and muscle activation in a young and elderly group of experienced computer users. Appl Ergon 36:547–555

    Article  PubMed  CAS  Google Scholar 

  • Schmidt RA, Zelaznik H, Hawkins B, Frank JS, Quinn JT Jr (1979) Motor-output variability: a theory for the accuracy of rapid motor acts. Psychol Rev 47:415–451

    Article  PubMed  CAS  Google Scholar 

  • Scholz JP, Schöner G (1999) The uncontrolled manifold concept: identifying control variables for a functional task. Exp Brain Res 126:289–306

    Article  PubMed  CAS  Google Scholar 

  • Selen LPJ, Beek PJ, Van Dieën JH (2005) Can co-activation reduce kinematic variability? A simulation study. Biol Cybern 93:373–381

    Article  PubMed  Google Scholar 

  • Shiller DM, Laboissiere R, Ostry DJ (2002) Relationship between jaw stiffness and kinematic variability in speech. J Neurophysiol 88:2329–2340

    Article  PubMed  Google Scholar 

  • Todorov E, Jordan MI (2002) Optimal feedback control as a theory of motor coordination. Nat Neurosci 5:1226–1235

    Article  PubMed  CAS  Google Scholar 

  • Van der Helm FC, Schouten AC, De Vlugt E, Brouwn GG (2002) Identification of intrinsic and reflexive components of human arm dynamics during postural control. J Neurosci Methods 119:1–14

    Article  PubMed  Google Scholar 

  • Van Galen GP, de Jong WP (1995) Fitts’ law as the outcome of a dynamic noise filtering model of motor control. Hum Mov Sci 12:539–571

    Google Scholar 

  • Van Galen GP, Van Huygevoort M (2000) Error, stress and the role of neuromotor noise in space oriented behaviour. Biol Psychol 51:151–171

    Article  PubMed  Google Scholar 

  • Van Gemmert AW, Van Galen GP (1997) Stress, neuromotor noise, and human performance: a theoretical perspective. J Exp Psychol Hum Percept Perform 23:1299–1313

    Article  PubMed  Google Scholar 

  • Van Roon D, Steenbergen B, Meulenbroek RG (2005) Trunk use and co-contraction in cerebral palsy as regulatory mechanisms for accuracy control. Neuropsychologia 43:497–508

    Article  PubMed  Google Scholar 

  • Visser B, De Looze M, De Graaff M, Van Dieën JH (2004) Effects of precision demands and mental pressure on muscle activation and hand forces in computer mouse tasks. Ergonomics 47:202–217

    Article  PubMed  Google Scholar 

  • Woodworth D (1899) The accuracy of voluntary movement. Psychol Rev 3:1–119

    Google Scholar 

  • Yang JF, Scholz JP (2005) Learning a throwing task is associated with differential changes in the use of motor abundance. Exp Brain Res 163:137–158

    Article  PubMed  Google Scholar 

  • Zhang LQ, Rymer WZ (1997) Simultaneous and nonlinear identification of mechanical and reflex properties of human elbow joint muscles. IEEE Trans Biomed Eng 44:1192–1209

    Article  PubMed  CAS  Google Scholar 

  • Zhang LQ, Rymer WZ (2001) Reflex and intrinsic changes induced by fatigue of human elbow extensor muscles. J Neurophysiol 86:1086–1094

    PubMed  CAS  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Jaap H. van Dieën.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Selen, L.P.J., Beek, P.J. & van Dieën, J.H. Impedance is modulated to meet accuracy demands during goal-directed arm movements. Exp Brain Res 172, 129–138 (2006). https://doi.org/10.1007/s00221-005-0320-7

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00221-005-0320-7

Keywords

Navigation