Contraction history produces task‐specific variations in spinal excitability in healthy human soleus muscle

Uematsu, Azusa; Sekiguchi, Hirofumi; Kobayashi, Hirofumi; Hortobágyi, Tibor; Suzuki, Shuji

doi:10.1002/mus.21989

Cited by 2 publications

(7 citation statements)

References 32 publications

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“…By contrast, as Fig. 2 shows, lengthening contractions with and without passive shortening depressed, and did not induce, potentiation of the H-reflex amplitude 13) . During lengthening contraction, despite the discharge rate of the Ia afferent being higher 39) , sizes of the H-reflex and MEPs were smaller than during shortening contraction [33][34][35][36][37][38] , suggesting that inhibitory components of the corticospinal volleys increase more during lengthening than shortening contraction.…”

Section: Acute After-effects Of Voluntary Contraction On Neural Excitmentioning

confidence: 67%

“…One limitation in the Uematsu et al (2011) study is that calibration isometric contractions did not precede the shortening and lengthening test contractions 13) . Previous studies failed to observe H-reflex potentiation after isometric contraction 8,9,26) , but these studies also only used follow-up H-reflex measurements up to 1 min after the conditioning contractions.…”

Section: Spinal Reflex Excitabilitymentioning

confidence: 97%

“…Recent experiments examined the after effects of shortening and lengthening contractions, and of a combination of shortening and lengthening contractions, on the spinal excitability of intact humans. To simulate as natural a sequence of human muscle function as possible, one study examined the changes in H-reflex amplitude following four tasks consisting of shortening contraction, lengthening contraction, passive shortening, and passive lengthening 13) . Fig.…”

Section: Acute After-effects Of Voluntary Contraction On Neural Excitmentioning

confidence: 99%

“…During lengthening contraction, despite the discharge rate of the Ia afferent being higher 39) , sizes of the H-reflex and MEPs were smaller than during shortening contraction [33][34][35][36][37][38] , suggesting that inhibitory components of the corticospinal volleys increase more during lengthening than shortening contraction. These neural activation characteristics, during muscle lengthening contraction, gave rise to speculation that lengthening contraction may have long-lasting after effects in the form of H-reflex depression 13) . Taken together, shortening contraction produces long-lasting potentiation, and lengthening contraction may produce a long-lasting depression of the H-reflex.…”

Section: Acute After-effects Of Voluntary Contraction On Neural Excitmentioning

confidence: 99%

“…These early results in animals were reproduced in intact humans using high frequency peripheral nerve stimulation producing tetanic contractions for more than 5 sec [5][6][7] , again suggesting a strong facilitation of spinal pathways up to 2 min after the end of the contractions. Recent studies in intact humans, using voluntary contractions at a moderate or high intensity and a duration of 5 to 60 sec, produced somewhat conflicting data because some studies found reflex facilitation [8][9][10][11][12][13] , but others failed to observe a doseresponse relationship or task specificity in the post-contraction reflex responses. In addition, previous studies using transcranial magnetic stimulation (TMS) revealed that corticospinal excitability was also facilitated after brief high-intensity muscle contractions (~60 sec) 14) .…”

Section: Introductionmentioning

confidence: 99%

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Mechanisms of post-contraction activation in skeletal muscle

Uematsu

Sekiguchi

Kobayashi

et al. 2012

JPFSM

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This review provides evidence for the task-, intensity-, and duration-specific modulation of twitch, spinal, corticospinal and cortical responses recorded up to ~18 min after the end of a muscle contraction produced by artificial and voluntary muscle activation in animal and human experimental models. Animal data revealed facilitation in spinal excitability after tetanic contraction; a phenomenon confirmed by human experiments using artificial, as well as voluntary, activation of muscle. There is evidence for a strong task-specific potentiation of spinal excitability associated with shortening and high intensity isometric contractions in contrast to depression after lengthening contractions. Contraction duration-specific effects suggest that when a contraction is performed to fatigue, post-exercise spinal excitability tends to decrease. Data from a limited number of transcranial magnetic brain stimulation studies suggest that, akin to spinal excitability, voluntary muscle contraction produces corticospinal and cortical excitability-associated changes. Of possible functional relevance, concerning these data, is that potentiation and depression in neural excitability can shape the mechanisms of how acute responses to exercise accumulate and convert to chronic adaptations. Of clinical relevance is that an even better understanding of the post-contraction effects would provide the opportunity for therapists to set exercise parameters according to the goals of therapy and need of patients and athletes to up/ down-regulate spinal, corticospinal, and cortical activity.

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Section: Acute After-effects Of Voluntary Contraction On Neural Excitmentioning

confidence: 67%

Section: Spinal Reflex Excitabilitymentioning

confidence: 97%

Section: Acute After-effects Of Voluntary Contraction On Neural Excitmentioning

confidence: 99%

Section: Acute After-effects Of Voluntary Contraction On Neural Excitmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Mechanisms of post-contraction activation in skeletal muscle

Uematsu

Sekiguchi

Kobayashi

et al. 2012

JPFSM

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Sex differences in muscle activity emerge during sustained low‐intensity contractions but not during intermittent low‐intensity contractions

2020

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Sex differences in motor performance may arise depending on the mode of contraction being performed. In particular, contractions that are held for long durations, rather than contractions that are interspersed with rest periods, may induce greater levels of fatigue in men compared to women. The purpose of this study was to examine fatigue responses in a cohort of healthy men (n = 7, age [mean] = 21.6 ± [SD]1.1 year) and women (n = 7, age: 22.0 ± 2.0 year) during sustained isometric and intermittent isometric contractions. Two contraction protocols were matched for intensity (20% MVC) and total contraction time (600-s). Biceps brachii EMG and elbow flexion torque steadiness were examined throughout each protocol, and motor nerve stimulation was used to quantify central and peripheral fatigue. Overall, there were few sex-related differences in the fatigue responses during intermittent contractions. However, men exhibited progressively lower maximal torque generation (39% versus 27% decrease), progressively greater muscle activity (220% versus 144% increase), progressively greater declines in elbow flexion steadiness (354% versus 285% decrease), and progressively greater self-perception of fatigue (Borg scale:8.8 ± 1.2 versus 6.3 ± 1.1) throughout the sustained contractions. The mechanism underlying fatigue responses had a muscle component, as voluntary activation of the biceps brachii did not differ between sexes, but the amplitude of resting twitches decreased throughout the sustained contractions (m: 32%, w: 10% decrease). As generating large sustained forces causes a progressive increase in intramuscular pressure and mechanical occlusion-which has the effect of enhancing metabolite accumulation and peripheral fatigue-it is likely that the greater maximal strength of men contributed to their exacerbated levels of fatigue.

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Contraction history produces task‐specific variations in spinal excitability in healthy human soleus muscle

Abstract: Our results suggest that spinal excitability is potentiated during a muscle action preceded by muscle shortening, but it becomes depressed during a muscle action preceded by muscle lengthening.

Cited by 2 publications

References 32 publications

Mechanisms of post-contraction activation in skeletal muscle

Mechanisms of post-contraction activation in skeletal muscle

Sex differences in muscle activity emerge during sustained low‐intensity contractions but not during intermittent low‐intensity contractions

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