The blood flow through active and inactive muscles of the forearm during sustained hand‐grip contractions

Humphreys, P. W.; Lind, A. R.

doi:10.1113/jphysiol.1963.sp007094

Cited by 267 publications

(143 citation statements)

References 7 publications

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“…Our results confirm these findings. The slope (-1.85) of the endurance function (plotted logarithmically) approximates those reported (-1.91, -1.85) in a number of experiments using different muscle groups (Humphreys & Lind, 1963;Petrofsky, 1980). The meaning of this relatively invariant feature of the isometric endurance function is uncertain, since the varying biochemical and contractile properties of muscles result in differences in fatigability (Clamann & Broecker, 1979).…”

Section: Methodssupporting

confidence: 48%

Perceived force in fatiguing isometric contractions

Jones

Hunter

1983

Perception & Psychophysics

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An integrative approach emphasizing both psychological and physiological components in force perception has started to emerge in motor psychophysics. In this experiment, the relation between isometric force (produced by the elbow flexors) and perceived force was examined over a range of forces maintained until maximal endurance. A contralateral-limb matching procedure in which subjects estimated the force of a sustained, constant force contraction by contracting their unfatigued arm at regular intervals was employed. A linear increase in perceived force was observed during the fatiguing contractions, the rate of which depended on the level of force exerted. The sensation of force at maxjma) endurance was also found to vary with the force exerted. Based on the similarity between these results and those derived from electromyographic studies, we propose that observers use the efferent input to the muscle in preference to its afferent responses in judging the force of muscular contractions.

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Section: Methodssupporting

confidence: 48%

Perceived force in fatiguing isometric contractions

Jones

Hunter

1983

Perception & Psychophysics

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“…Contractions at 20 % MVC are only mildly fatiguing, blood flow is elevated during the contractions and post-exercise hyperaemia is only transient (Humphreys & Lind, 1963;Lind & McNicol, 1967 b). The oxygen requirements of the muscle are largely met during exercise which confirms the lack of oxygen debt observed in the present studies.…”

Section: Alveolar Pco2mentioning

confidence: 99%

Respiratory responses to sustained isometric muscle contractions in man: the effect of muscle mass.

Imms

Mehta

1989

The Journal of Physiology

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SUMMARY1. Respiratory responses to sustained isometric contractions of a small mass of muscle (the finger flexors) during handgripping, and of a larger mass of muscle (the quadriceps) during extension of the leg at the knee, have been studied in man.2. For both masses of muscle the increases of ventilation and of oxygen consumption were greater for contractions at 40 % maximum voluntary contraction (MVC) than for contractions at 20 % MVC.3. The increase of ventilation was not related to the mass of muscle involved. 4. At 20% MVC oxygen consumption during contraction of the quadriceps was greater than that during handgripping. At 40 % MVC the oxygen consumptions were similar. The oxygen debts following both handgrip and knee extensor contractions at 20 % MVC were negligible. Following 40 % MVC contractions of the quadriceps a significant oxygen debt was recorded but no debt was apparent following 40 % MVC contractions of the finger flexors.5. The increases of ventilation during isometric exercise were generally inappro-

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“…Moreover, intramuscular pressure and the associated degree of blood flow occlusion increase linearly with an increasing intensity of contraction. [19][20][21][22][23][24][25][26][27] It can be postulated that muscular hypertonia, spasticity, and contractures induce a state of relative ischemia.…”

Section: Why Free Radical Scavengers?mentioning

confidence: 99%

“…[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] Ischemia/Reperfusion Syndrome An isometric muscle contraction accompanied by an elevation of muscular pressure, consequent upon vascular occlusion, can induce a state of relative ischemia in an extremity. Such elevations compress and may even occlude the arteries if the pressure becomes fairly high.…”

Section: Why Free Radical Scavengers?mentioning

confidence: 99%

Free radical scavengers are more effective than indomethacin in the prevention of experimentally induced heterotopic ossification

Bossche

Maele

Wojtowicz

et al. 2006

Journal Orthopaedic Research

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The pathogenesis of heterotopic ossification is still unclear and the preventive therapies are usually insufficient. The present study was designed to investigate the possible preventive effect of free radical scavengers on the development of experimentally induced heterotopic ossification in a rabbit model and to compare free radical scavengers with indomethacin to determine whether they act synergistically. A standard immobilization-manipulation model was used to induce heterotopical ossification in the hind legs of 40 1-year-old female New Zealand albino rabbits. The animals were divided into four groups and received daily either placebo, a free radical scavenger cocktail [allopurinol and N-acetylcysteine (A/A)], indomethacin or the combination of A/A and indomethacin in a randomized double-blind fashion. Every 4 days an X-ray was taken and the thickness and length of new bone formation was measured at the thigh. A marked statistically significant difference was found between the four groups. In the groups that received A/A, either alone or combined with indomethacin, an inhibition of bone growth, both in thickness and in length was demonstrated. In this experimental model free radical scavengers had a superior inhibitory effect on heterotopic ossification than indomethacin. Free radicals could play an important role in the pathogenesis of heterotopic ossification. ß

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The blood flow through active and inactive muscles of the forearm during sustained hand‐grip contractions

Cited by 267 publications

References 7 publications

Perceived force in fatiguing isometric contractions

Perceived force in fatiguing isometric contractions

Respiratory responses to sustained isometric muscle contractions in man: the effect of muscle mass.

Free radical scavengers are more effective than indomethacin in the prevention of experimentally induced heterotopic ossification

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