Characteristics of the muscle mechanoreflex during quadriceps contractions in humans

Michael D. Herr, Virginia Imadojemu, Allen R. Kunselman, Lawrence I. Sinoway

Research output: Contribution to journalArticle

65 Citations (Scopus)

Abstract

We examined muscle sympathetic nerve activity (MSNA) in the nonexercising lower limb during repetitive static quadriceps contraction paradigm at 25% maximal voluntary contraction in eight men. Subjects performed 20-s contractions with 5-s rest periods for up to 12 contractions. Although the workload was constant, we found that MSNA amplitude rose as a function of contraction number [0.6 In (amplitude/min)/contraction]; this suggests chemical sensitization of the muscle reflex response. We employed signal-averaging techniques and then integrated the data to examine the onset latency of the MSNA response as a function of the 25-s contraction-rest period. We observed an onset latency of ~4-6 s. Moreover, although the onset latency did not appear to vary as a function of contraction number, the rate of MSNA increase took approximately four contractions to reach a steady- state rate of rise; this suggests contraction-induced sensitization. The onset latency reported here is similar to findings in recent animal studies, but it is at odds with latencies determined in prior human handgrip contraction studies. We believe our data suggest that 1) mechanically sensitive afferents contribute importantly to the MSNA response to the paradigm employed and 2) these afferents may be sensitized by the chemical products of muscle contraction.

Original languageEnglish (US)
Pages (from-to)767-772
Number of pages6
JournalJournal of applied physiology
Volume86
Issue number2
DOIs
StatePublished - Feb 1999

Fingerprint

Muscles
Muscle Contraction
Workload
Reflex
Lower Extremity

All Science Journal Classification (ASJC) codes

  • Physiology
  • Physiology (medical)

Cite this

@article{c06d4369068f4ff0a467b4c02d73604b,
title = "Characteristics of the muscle mechanoreflex during quadriceps contractions in humans",
abstract = "We examined muscle sympathetic nerve activity (MSNA) in the nonexercising lower limb during repetitive static quadriceps contraction paradigm at 25{\%} maximal voluntary contraction in eight men. Subjects performed 20-s contractions with 5-s rest periods for up to 12 contractions. Although the workload was constant, we found that MSNA amplitude rose as a function of contraction number [0.6 In (amplitude/min)/contraction]; this suggests chemical sensitization of the muscle reflex response. We employed signal-averaging techniques and then integrated the data to examine the onset latency of the MSNA response as a function of the 25-s contraction-rest period. We observed an onset latency of ~4-6 s. Moreover, although the onset latency did not appear to vary as a function of contraction number, the rate of MSNA increase took approximately four contractions to reach a steady- state rate of rise; this suggests contraction-induced sensitization. The onset latency reported here is similar to findings in recent animal studies, but it is at odds with latencies determined in prior human handgrip contraction studies. We believe our data suggest that 1) mechanically sensitive afferents contribute importantly to the MSNA response to the paradigm employed and 2) these afferents may be sensitized by the chemical products of muscle contraction.",
author = "Herr, {Michael D.} and Virginia Imadojemu and Kunselman, {Allen R.} and Sinoway, {Lawrence I.}",
year = "1999",
month = "2",
doi = "10.1152/jappl.1999.86.2.767",
language = "English (US)",
volume = "86",
pages = "767--772",
journal = "Journal of Applied Physiology",
issn = "8750-7587",
publisher = "American Physiological Society",
number = "2",

}

Characteristics of the muscle mechanoreflex during quadriceps contractions in humans. / Herr, Michael D.; Imadojemu, Virginia; Kunselman, Allen R.; Sinoway, Lawrence I.

In: Journal of applied physiology, Vol. 86, No. 2, 02.1999, p. 767-772.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Characteristics of the muscle mechanoreflex during quadriceps contractions in humans

AU - Herr, Michael D.

AU - Imadojemu, Virginia

AU - Kunselman, Allen R.

AU - Sinoway, Lawrence I.

PY - 1999/2

Y1 - 1999/2

N2 - We examined muscle sympathetic nerve activity (MSNA) in the nonexercising lower limb during repetitive static quadriceps contraction paradigm at 25% maximal voluntary contraction in eight men. Subjects performed 20-s contractions with 5-s rest periods for up to 12 contractions. Although the workload was constant, we found that MSNA amplitude rose as a function of contraction number [0.6 In (amplitude/min)/contraction]; this suggests chemical sensitization of the muscle reflex response. We employed signal-averaging techniques and then integrated the data to examine the onset latency of the MSNA response as a function of the 25-s contraction-rest period. We observed an onset latency of ~4-6 s. Moreover, although the onset latency did not appear to vary as a function of contraction number, the rate of MSNA increase took approximately four contractions to reach a steady- state rate of rise; this suggests contraction-induced sensitization. The onset latency reported here is similar to findings in recent animal studies, but it is at odds with latencies determined in prior human handgrip contraction studies. We believe our data suggest that 1) mechanically sensitive afferents contribute importantly to the MSNA response to the paradigm employed and 2) these afferents may be sensitized by the chemical products of muscle contraction.

AB - We examined muscle sympathetic nerve activity (MSNA) in the nonexercising lower limb during repetitive static quadriceps contraction paradigm at 25% maximal voluntary contraction in eight men. Subjects performed 20-s contractions with 5-s rest periods for up to 12 contractions. Although the workload was constant, we found that MSNA amplitude rose as a function of contraction number [0.6 In (amplitude/min)/contraction]; this suggests chemical sensitization of the muscle reflex response. We employed signal-averaging techniques and then integrated the data to examine the onset latency of the MSNA response as a function of the 25-s contraction-rest period. We observed an onset latency of ~4-6 s. Moreover, although the onset latency did not appear to vary as a function of contraction number, the rate of MSNA increase took approximately four contractions to reach a steady- state rate of rise; this suggests contraction-induced sensitization. The onset latency reported here is similar to findings in recent animal studies, but it is at odds with latencies determined in prior human handgrip contraction studies. We believe our data suggest that 1) mechanically sensitive afferents contribute importantly to the MSNA response to the paradigm employed and 2) these afferents may be sensitized by the chemical products of muscle contraction.

UR - http://www.scopus.com/inward/record.url?scp=0033052808&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0033052808&partnerID=8YFLogxK

U2 - 10.1152/jappl.1999.86.2.767

DO - 10.1152/jappl.1999.86.2.767

M3 - Article

C2 - 9931219

AN - SCOPUS:0033052808

VL - 86

SP - 767

EP - 772

JO - Journal of Applied Physiology

JF - Journal of Applied Physiology

SN - 8750-7587

IS - 2

ER -