TY - JOUR
T1 - Cardiovascular and respiratory responses to changes in central command during isometric exercise at constant muscle tension
AU - Goodwin, G. M.
AU - McCloskey, D. I.
AU - Mitchell, J. H.
N1 - Copyright:
Copyright 2015 Elsevier B.V., All rights reserved.
PY - 1972/10/1
Y1 - 1972/10/1
N2 - 1. Experiments were designed to show whether elements of the command descending from higher centres to exercising muscles provide an input for cardiovascular and respiratory control. Vibration, known to be a powerful stimulus to the primary afferents from muscle spindles, was applied to the biceps tendon of human subjects performing sustained isometric contractions with the biceps or the triceps muscle. When the biceps was contracting this activation of muscle spindle primary afferents in it provided an element of reflex excitation, so that less central command was required to achieve a given tension. When triceps was contracting, the activation of muscle spindle primary afferents in its antagonist, biceps, contributed an element of reflex inhibition, so that more central command than normally was required to achieve a given tension. The cardiovascular and respiratory responses to an isometric effort could thus be investigated at any tension when the central command was normal, decreased, or increased. 2. Blood pressure, heart rate, and pulmonary ventilation all increase in an isometric effort. The increase in each is less when the central command is reduced. The increase in each is greater when the central command is increased. 3. It is concluded that there is irradiation of cardiovascular and respiratory control centres by the descending central command during voluntary muscular contractions in man.
AB - 1. Experiments were designed to show whether elements of the command descending from higher centres to exercising muscles provide an input for cardiovascular and respiratory control. Vibration, known to be a powerful stimulus to the primary afferents from muscle spindles, was applied to the biceps tendon of human subjects performing sustained isometric contractions with the biceps or the triceps muscle. When the biceps was contracting this activation of muscle spindle primary afferents in it provided an element of reflex excitation, so that less central command was required to achieve a given tension. When triceps was contracting, the activation of muscle spindle primary afferents in its antagonist, biceps, contributed an element of reflex inhibition, so that more central command than normally was required to achieve a given tension. The cardiovascular and respiratory responses to an isometric effort could thus be investigated at any tension when the central command was normal, decreased, or increased. 2. Blood pressure, heart rate, and pulmonary ventilation all increase in an isometric effort. The increase in each is less when the central command is reduced. The increase in each is greater when the central command is increased. 3. It is concluded that there is irradiation of cardiovascular and respiratory control centres by the descending central command during voluntary muscular contractions in man.
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U2 - 10.1113/jphysiol.1972.sp009979
DO - 10.1113/jphysiol.1972.sp009979
M3 - Article
C2 - 4263680
AN - SCOPUS:0015418946
SN - 0022-3751
VL - 226
SP - 173
EP - 190
JO - The Journal of Physiology
JF - The Journal of Physiology
IS - 1
ER -