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Cited by 84Muscle activation and electromyography studiesMotor Control and AdaptationPain Mechanisms and Treatments

Mechanism of monosynaptic reflex reinforcement during Jendrassik manoeuvre in man.

Open access
Bussel, B, Morin, C, Pierrot-Deseilligny, E·1978·Journal of Neurology, Neurosurgery & Psychiatry
DOI 10.1136/jnnp.41.1.40PMC PMC492960
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Abstract

The facilitating effect of the Jendrassik manoeuvre on monosynaptic reflexes in man has been studied by comparing H and T reflexes of the soleus and by blocking the effects of spindle activation by ischaemia of the leg. The Jendrassik manoeuvre equally enhances H and T reflexes provided that the test reflexes are small. The H reflex remains facilitated when the spindle activation cannot affect the soleus alpha-motoneurones--that is, when the Ia afferent nerve fibres from the soleus are blocked by ischaemia. It is concluded that the facilitating effect of the Jendrassik manoeuvre on the alpha-motoneurones is not predominantly routed via the gamma-loop.

AI snapshot

Written from the paper’s full text.

TL;DR

The Jendrassik manoeuvre facilitated both soleus H and T reflexes to a similar degree when the test reflexes were small, and H-reflex facilitation persisted after ischaemic block of Ia afferents abolished the tendon reflex. The authors conclude that the reinforcement is not mainly mediated through the gamma-loop but instead reflects direct facilitation of alpha motoneurones.

Key findings

  • In one representative subject, a brisk strong handgrip increased both H and T reflexes by about 50%; across subjects, facilitated H reflexes ranged from 122% to 185% of control and T reflexes from 140% to 196% of control.
  • Sustained handgrip produced weaker facilitation than brisk handgrip. In one subject, mean H-reflex facilitation at 25%, 50%, and 100% maximal force was 131%, 152%, and 150% of control, while T-reflex facilitation was 135%, 140%, and 180%.
  • During leg ischaemia, the Achilles tendon reflex began to diminish 20–27 minutes after cuff inflation and was abolished around 30 minutes, while H and M responses remained unchanged. Under this Ia block, both reinforcement manoeuvres still facilitated the H reflex, with values ranging from 135% to 197% across subjects, whereas the T reflex was absent.
  • The authors conclude that the Jendrassik effect does not act predominantly by facilitating gamma-motoneurones.

Methods

  • Five healthy adult volunteers aged 26–41 were seated with hip and knee flexed; soleus H reflexes were evoked by posterior tibial nerve stimulation with 1 ms rectangular pulses, and T reflexes by an electromagnetic hammer producing a 5 ms, 8 mm stretch.
  • Control T-reflex amplitude was set to half maximum, and H-reflex stimulation was adjusted so H and T amplitudes were approximately equal. Jendrassik manoeuvres were either a brisk 1-second bilateral handgrip every 3 seconds with the test reflex 400 ms after onset, or a sustained handgrip at maximal, half-maximal, and quarter-maximal force using a dynamometer.
  • Surface EMG from soleus was taped and computer-analysed; mean H and T amplitudes over 30-second periods were expressed as percentages of the maximum direct M response. Ischaemia was produced by a thigh cuff inflated to 300 mm Hg below the H-reflex stimulation site.

Limitations

  • The paper states that sustained handgrip effects were less marked, so with subjects showing high reflex variability more trials would be needed; because the ischaemic period was necessarily short, sustained-handgrip effects were studied only in subjects with low variability.
  • The authors state that their findings do not rule out gamma-motoneurone activation during the manoeuvre, only that it is not the predominant route.
  • Evident from the text: the sample was small (five healthy adults), some results are illustrated from single subjects, and no formal statistical analysis is described.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1136/jnnp.41.1.40

Cites

9 of 9 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 3 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    The soleus H reflex remains facilitated during the Jendrassik manoeuvre when spindle activation cannot affect the soleus alpha-motoneurones, i.e., when the Ia afferent fibres from the soleus are blocked by ischaemia.

    “The H reflex remains facilitated when the spindle activation cannot affect the soleus a-motoneurones-that is, when the Ia afferent nerve fibres from the soleus are blocked by ischaemia.”
    • Also stated in: § EFFECTS OF ISCHAEMIA OF THE LEG ON THE H REFLEX FACILITATION OBSERVED DURING REINFORCEMENT MANOEUVRES · plain
      “Under these conditions, both kinds of rein- forcement manoeuvre still result in a facilitated H reflex which varied among the subjects between 135% and 197% (Fig. lF; right part of Figs. 2, 3).”
    Quote in the paperSubstantial claim
  • Findingown data

    The Jendrassik manoeuvre equally enhances the soleus H and T reflexes provided that the test reflexes are small.

    “The Jendrassik manoeuvre equally enhances H and T reflexes provided that the test reflexes are small.”
    • Also stated in: § EFFECTS OF TWO KINDS OF REINFORCING MANOEUVRE ON H AND T REFLEXES · plain
      “there was an increase of about 50% in the amplitude of both H and T reflexes with the Jendrassik manoeuvre, and that the facilitation of the Achilles reflex was no stronger than that of the H reflex.”
    Quote in the paperSubstantial claim
  • Findingown data

    During sustained handgrip, the amount of facilitation of H and T reflexes depends on the strength of the handgrip.

    “Throughout the control period the H and T reflexes were usually more facilitated when obtained during a stronger handgrip.The mean value of the facilitation obtained when the handgrip was 25%, 50%, and 100% of the maxi- mal force was 131%, 152%, and 150% respec- tively of the corresponding H reflex control or 135%, 140%, and 180% of the corresponding T reflex control.”
    Quote in the paperSubstantial claim
  • Findingcitation

    The effect of a sustained handgrip on H and T reflexes is much less marked than that of a brisk handgrip.

    “As claimed by Paillard (1955), the effect of a sustained handgrip upon H and T reflexes is much less marked than that of a brisk handgrip.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Paillard (1955)

      Not checked in the free run.

  • Interpretationown data

    The facilitating effect of the Jendrassik manoeuvre on alpha-motoneurones is not predominantly routed via the gamma-loop.

    “It is concluded that the facilitating effect of the Jendrassik manoeuvre on the a-motoneurones is not predominantly routed via the y-loop.”
    Quote in the paperSubstantial claim
  • May combine two claims. 5
  • Classified as probably not a substantial claim. 3

  • May combine two claims.

    Findingown data

    The facilitated H reflex amplitude varied among subjects between 122% and 185% of control, and the facilitated T reflex amplitude varied between 140% and 196% of control.

    “The ampli- tude of the facilitated reflexes varied among the subjects between 122% and 185% of their control value for the H reflex (Fig. lB and D), and be- tween 140% and 196% for the tendon reflex (Fig. IC and D).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingreasoning

    Twenty to 27 minutes after the onset of ischaemia, the Achilles tendon reflex began to diminish; about 30 min after inflation, the test H reflex and M response were no smaller than at onset, and the Achilles tendon reflex was completely abolished.

    “Twenty to 27 minutes after the onset of ischaemia, the amplitude of the Achilles tendon reflex began to diminish; it then decreased more and more.About 30 min after the inflation of the cuff, the test H reflex and the M response were no smaller than at the onset of ischaemia, the Achilles tendon reflex being completely abolished (Fig. 1G).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductown data

    The amplitude of H and T reflexes was identical before ischaemia and during the early minutes of ischaemia, so the first 15 minutes of ischaemia could be considered a control period.

    “The ampli- tude of H and T reflexes was identical before ischaemia and during the early minutes of ischae- mia.Therefore, the first 15 minutes of the ischaemia could be considered as a control period.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Premisenone given

    It is not known whether the enhancement is predominantly due to direct facilitation of alpha-motoneurones or to an increase in spindle activity induced by gamma-activation.

    “It is not known whether this enhance- ment is predominantly due to a direct facilitation of a-motoneurones or to an increase in spindle activity induced by y-activation.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Premisenone given

    The mechanism for reinforcement of tendon reflexes by the Jendrassik manoeuvre is not yet clear.

    “The facilitating effect of the Jendrassik man- oeuvre on tendon reflexes in man is well-known but the mechanism for this reinforcement is not yet clear.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    The M response was unchanged during ischaemia, so it is likely that group II fibres were not blocked, since they are smaller than alpha-fibres.

    “Since the M response was unchanged, it is likely that group II fibres were not blocked, since they are smaller than a-fibres.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Group II afferent fibres are smaller than alpha motor fibres.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    During the control period, the amplitude of both H and T reflexes was kept equal to approximately 20% of the maximum M response.

    “During this control period, it was possible to keep the amplitude of both H and T reflexes equal to approximately 20% of the maximum M response”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Group II fibres are generally considered to inhibit soleus motoneurones and therefore cannot be responsible for the persistence of H reflex facilitation.

    “but they are generally considered as inhibiting * * ... soleus motoneurones (Eccles and Lundberg, 1959) and can, therefore, not be responsible for the persistence of the H reflex facilitation.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Eccles and Lundberg, 1959

      Not checked in the free run.

8 of 8

  • The paper relies on this without support.

    The soleus H reflex bypasses the soleus spindles and does not depend directly on gamma-fibre activity.

    “This electrically evoked H reflex is also a monosynaptic reflex of the soleus, but it bypasses the solcus spindles, and, therefore, does not depend directly on y-fibre activity.”

  • The paper relies on this without support.

    Group II afferent fibres are smaller than alpha motor fibres.

    “Since the M response was unchanged, it is likely that group II fibres were not blocked, since they are smaller than a-fibres.”
2 of 2

Cites

Flagged first, then by citations

Research works printed but not linked: 1

  1. Jendrassik, E. (1883). Beitrage zur Lehre von den Sehnenreflexen. Deutsches A rchiv fiir Klinische Medizin, 33, 177-199.

Cited by

Sorted by citations

Related

Authors
Bussel, B., Morin, C., & Pierrot-Deseilligny, E.
Affiliations
Pitié-Salpêtrière Hospital (FR)
ORCID
Morin, C
Venue
Journal of Neurology, Neurosurgery & Psychiatry
Publisher
BMJ
Published
1978-01-01
Volume
41
Issue
1
Pages
40-44
ISSN
0022-3050 (ISSN-L)
DOI
10.1136/jnnp.41.1.40
PMC
PMC492960
OpenAlex
W2141921311
Cited by
84
References
9
Citations by year
2023: 1 · 2022: 1 · 2021: 3 · 2020: 1 · 2019: 3 · 2017: 2 · 2014: 2 · 2013: 1 · 2012: 2
FWCI
3.89
Type
journal article
Language
en
Open access
Locations
  • Journal of Neurology Neurosurgery & Psychiatry (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • HighWire Press Open Archive (submittedVersion)
Topics
  • Physical Sciences › Engineering › Biomedical Engineering › Muscle activation and electromyography studies
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Motor Control and Adaptation
  • Health Sciences › Medicine › Physiology › Pain Mechanisms and Treatments
Keywords
monosynaptic reflex, H-reflex, T-reflex, soleus muscle, alpha motoneurons, gamma loop, muscle spindles, ischemia, reflex facilitation, motor control
MeSH terms
Achilles Tendon, Adult, H-Reflex, Humans, Ischemia, Leg, Methods, Motor Neurons, Nerve Block, Neurons, Afferent, Reflex, Monosynaptic, Reflex, Stretch

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