Annals of Biomedical Engineering

, Volume 29, Issue 12, pp 1122–1134 | Cite as

Effect of Muscle Biomechanics on the Quantification of Spasticity

  • D. G. Kamper
  • B. D. Schmit
  • W. Z. Rymer


The impact of muscle biomechanics on spasticity was assessed by comparison of the reflex responses of the elbow and metacarpophalangeal (MCP) flexor muscles in individuals with chronic spastic hemiplegia following stroke. Specifically, methods were developed to quantify reflex responses and to normalize these responses for comparison across different muscle groups. Stretch reflexes were elicited in the muscles of interest by constant velocity ramp-and-hold stretches at the corresponding joint. The muscles were initially passive, with the joint placed in a midrange position. Estimates of biomechanical parameters were used to convert measured reflex joint torque and joint angle into composite flexor muscle stress and stretch. We found that the stretch reflex response for the MCP muscle group had a 74% greater mean stiffness modulus than that for the elbow muscle group, and that the reflex threshold was initiated at an 80% shorter mean muscle stretch. However, we determined that initial normalized fiber length was significantly greater for the experiments involving the MCP muscles than for those involving the elbow muscles. Increasing the initial composite fiber length of the elbow flexors produced significant reduction of the reflex threshold (p < 0.001), while decreasing the initial length of the MCP flexors significantly reduced their measured reflex stiffness (p < 0.001). Thus, biomechanical parameters of muscle do appear to have an important effect on the stretch reflex in individuals with impairment following stroke, and this effect should be accounted for when attempting to quantify spasticity. © 2001 Biomedical Engineering Society.

PAC01: 8719Rr

Stretch reflex Fiber length Stroke 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Al-Falahe, N. A., M. Nagaoka, and A. B. Vallbo. Response profiles of human muscle afferents during active finger movements. Brain 113:325–346, 1990.Google Scholar
  2. 2.
    Amis, A. A., D. Dowson, and V. Wright. Muscle strengths and musculoskeletal geometry of the upper limb. Eng. Med. 8:41–48, 1979.Google Scholar
  3. 3.
    An, K. N., E. Y. Chao, W. P. Cooney, and R. L. Linscheid. Normative model of human hand for biomechanical analysis. J. Biomech. 12:775–788, 1979.Google Scholar
  4. 4.
    An, K. N., E. Y. Chao, W. P. Cooney, and R. L. Linscheid. Forces in the normal and abnormal hand. J. Orthop. Res. 3:202–211, 1985.Google Scholar
  5. 5.
    An, K. N., Y. Ueba, E. Y. Chao, W. P. Cooney, and R. L. Linscheid. Tendon excursion and moment arm of index finger muscles. J. Biomech. 16:419–425, 1983.Google Scholar
  6. 6.
    Ashworth, B. Preliminary trial of carisoprodol in multiple sclerosis. Practitioner 192:540–542, 1964.PubMedGoogle Scholar
  7. 7.
    Cameron, T., K. McDonald, L. Anderson, and A. Prochazka. The effect of wrist angle on electrically evoked hand opening in patients with spastic hemiplegia. IEEE Trans. Rehabil. Eng. 7:109–111, 1999.Google Scholar
  8. 8.
    Cholewicki, J., S. M. McGill, and R. W. Norman. Comparison of muscle forces and joint load from an optimization and EMG assisted lumbar spine model: Towards development of a hybrid approach. J. Biomech. 28:321–331, 1995.Google Scholar
  9. 9.
    Delp, S. L., and F. E. Zajac. Force-and moment-generating capacity of lower-extremity muscles before and after tendon lengthening. Clin. Orthop. Relat. Res. 284:247–259, 1992.Google Scholar
  10. 10.
    Esteki, A., and J. M. Mansour. A dynamic model of the hand with application in functional neuromuscular stimulation. Ann. Biomed. Eng. 25:440–451, 1997.Google Scholar
  11. 11.
    Given, J. D., J. P. A. Dewald, and W. Z. Rymer. Joint dependent passive stiffness in paretic and contralateral limbs of spastic patients with hemiparetic stroke. J. Neurol. Neurosurg. Psychiatry 59:271–279, 1995.Google Scholar
  12. 12.
    He, J.. Stretch reflex sensitivity: Effects of postural and muscle length changes. IEEE Trans. Rehabil. Eng. 6:182–189, 1998.Google Scholar
  13. 13.
    Herbert, R. D., and R. J. Balnave. The effect of position of immobilization on resting length, resting stiffness, and weight of the soleus muscle of the rabbit. J. Orthop. Res. 11:358–366, 1993.Google Scholar
  14. 14.
    Houk, J. C., W. Z. Rymer, and P. E. Crago. Dependence of dynamic response of spindle receptors on muscle length and velocity. J. Neurophysiol. 46:143–166, 1981.Google Scholar
  15. 15.
    Hoy, M. G., F. E. Zajaz, and M. E. Gordon. A musculoskeletal model of the human lower extremity: The effect of muscle, tendon, and moment arm on the momentangle relationship of musculotendon actuators at the hip, knee, and ankle. J. Biomech. 23:157–169, 1990.Google Scholar
  16. 16.
    Hulliger, M., E. Nordh, and A. B. Vallbo. The absence of position response in spindle afferent units from human finger muscles during accurate position holding. J. Physiol. (London) 322:167–179, 1982.Google Scholar
  17. 17.
    Illert, M., and H. Kummel. Reflex pathways from large muscle spindle afferents and recurrent axon collaterals to motoneurones of wrist and digit muscles: A comparison in cats, monkeys, and humans. Exp. Brain Res. 128:13–19, 1999.Google Scholar
  18. 18.
    Johansson, R. S., and A. B. Vallbo. Tactile sensory coding in the glabrous skin of the human hand. Trends Neurosci<nt></nt>. 6:27–32, 1983.Google Scholar
  19. 19.
    Kamper, D. G., and W. Z. Rymer. Quantitative features of the stretch response of extrinsic finger muscles in hemiparetic stroke. Muscle Nerve 23:954–961, 2000.Google Scholar
  20. 20.
    Knuttson, E., and A. Martensson. Dynamic motor capacity in spastic paresis and its relation to prime mover dysfunction, spastic reflexes, and antagonist coactivation. Scand. J. Rehabil. Med. 12:93–106, 1980.Google Scholar
  21. 21.
    Lance, J. W. The control of muscle tone, reflexes, and movement: Robert Wartenberg Lecture. Neurology 30:1303–1313, 1980.Google Scholar
  22. 22.
    Lieber, R. L., M. D. Jacobson, B. M. Fazeli, R. A. Abrams, and M. J. Botte. Architecture of selected muscles of the arm and forearm: Anatomy and implications for tendon transfer. J. Hand Surg. [Am] 17A:787–798, 1992.Google Scholar
  23. 23.
    Matthews, P. B. C. The response of de-efferented muscle spindle receptors to stretching at different velocities. J. Physiol. (London) 168:660–678, 1963.Google Scholar
  24. 24.
    Meinders, M., R. Price, J. F. Lehmann, and K. A. Questad. The stretch reflex response in the normal and spastic ankle: Effect of ankle position. Arch. Phys. Med. Rehabil. 77:487–492, 1996.Google Scholar
  25. 25.
    Mirbagheri, M. M., H. Barbeau, and R. E. Kearney. Intrinsic and reflex contributions to human ankle stiffness: Variation with activation level and position. Exp. Brain Res. 135:424–436, 2000.Google Scholar
  26. 26.
    Murray, W. M. The functional capacity of the elbow muscles: Anatomical measurements, computer modeling, and anthropometric scaling. PhD Dissertation, Northwestern University, Evanston, IL, 1997.Google Scholar
  27. 27.
    Murray, W. M., T. S. Buchanan, and S. L. Delp. The isometric functional capacity of muscles that cross the elbow. J. Biomech. 33:943–952, 2000.Google Scholar
  28. 28.
    Nielsen, J. F., and T. Sinkjaer. A comparison of clinical and laboratory measures of spasticity. Mult. Scler. 1:296–301, 1996.Google Scholar
  29. 29.
    Palmer, E., and P. Ashby. Corticospinal projections to upper limb motoneurones in humans. J. Physiol. (Paris) 448:397–412, 1992.Google Scholar
  30. 30.
    Porter, R., and R. N. Lemon. Corticospinal Function and Voluntary Movement. Oxford: Clarendon, 1993.Google Scholar
  31. 31.
    Powers, R. K., J. Marder-Meyer, and W. Z. Rymer. Quantitative relations between hypertonia and stretch reflex threshold in spastic hemiparesis. Ann. Neurol. 23:115–124, 1988.Google Scholar
  32. 32.
    Rebersek, S., A. Stefanovska, L. Vodovnik, and N. Gros. Some properties of spastic ankle joint muscles in hemiplegia. Med. Biol. Eng. Comput. 24:19–26, 1986.Google Scholar
  33. 33.
    Rymer, W. Z., and R. T. Katz. Mechanical quantification of spastic hypertonia. Physical Med. Rehabil.: State Art Rev. 8:455–463, 1994.Google Scholar
  34. 34.
    Schmit, B. D., Y. Dhaher, J. P. A. Dewald, and W. Z. Rymer. Reflex torque response to movement of the spastic elbow: Theoretical analyses and implication for quantification of spasticity. Ann. Biomed. Eng. 27:815–829, 1999.Google Scholar
  35. 35.
    Schmit, B. D., J. P. A. Dewald, and W. Z. Rymer. Stretch reflex adaptation in elbow flexors during repeated passive movements in unilateral brain-injured patients. Arch. Phys. Med. Rehabil. 81:269–278, 2000.Google Scholar
  36. 36.
    Sinkjaer, T., T. Egon, S. Andreassen, and B. C. Hornemann. Muscle stiffness in human ankle dorsiflexors: Intrinsic and reflex components. J. Neurophysiol. 60:1110–1121, 1988.Google Scholar
  37. 37.
    Sparto, P. J., and M. Parnianpour. An electromyography-assisted model to estimate trunk muscle forces during fatiguing repetitive trunk exertions. J. Spinal Disorders 12:509–518, 1999.Google Scholar
  38. 38.
    Thilmann, A. F., S. J. Fellows, and H. F. Ross. Biomechanical changes at the ankle joint after stroke. J. Neurol. Neurosurg. Psychiatry 54:134–139, 1991.Google Scholar
  39. 39.
    Valero-Cuevas, F. J., F. E. Zajac, and C. G. Burgar. Large index-fingertip forces are produced by subject-independent patterns of muscle excitation. J. Biomech. 31:693–703, 1998.Google Scholar
  40. 40.
    Weiss, P. L., R. E. Kearney, and I. W. Hunter. Position dependence of stretch reflex dynamics at the human ankle. Exp. Brain Res. 63:49–59, 1986.Google Scholar
  41. 41.
    Williams, P. E., and G. Goldspink. Connective tissue changes in immobilized muscle. J. Anat. 138:343–350, 1984.Google Scholar
  42. 42.
    Wolf, S. L., R. L. Segal, P. A. Catlin, J. Tschorn, T. Raleigh, H. Kontos, and P. Pate. Determining consistency of elbow joint threshold angle in elbow flexor muscles with spastic hypertonia. Phys. Ther. 76:586–600, 1996.Google Scholar
  43. 43.
    Zajac, F. E.. How musculotendon architecture and joint geometry affect the capacity of muscles to move and exert force on objects: A review with application to arm and forearm tendon transfer design. J. Hand Surg. 17A:799–804, 1992.Google Scholar
  44. 44.
    Zajac, F. E. Muscle and tendon: Properties, models, scaling, and application to biomechanics and motor control. Crit. Rev. Biomed. Eng. 17:359–411, 1989.Google Scholar

Copyright information

© Biomedical Engineering Society 2001

Authors and Affiliations

  • D. G. Kamper
    • 1
  • B. D. Schmit
    • 2
  • W. Z. Rymer
    • 1
  1. 1.Sensory Motor Performance Program, Rehabilitation Institute of Chicago Department of Physical Medicine and RehabilitationNorthwestern UniversityChicago
  2. 2.Biomedical Engineering DepartmentMarquette UniversityMilwaukee

Personalised recommendations