WS3.3. The Values of H-Reflex and Other Late Responses in Disease

AbstractDuring voluntary contractions, corticomuscular coherence (CMC) is thought to reflect a mutual interaction between cortical and muscle oscillatory activities, respectively measured by electroencephalography (EEG) and electromyography (EMG). However, it remains unclear whether CMC modulation would depend on the contribution of neural mechanisms acting at the spinal level. To this purpose, modulations of CMC were compared during submaximal isometric, shortening and lengthening contractions of the soleus (SOL) and the medial gastrocnemius (MG) with a concurrent analysis of changes in spinal excitability that may be reduced during lengthening contractions. Submaximal contractions intensity was set at 50% of the maximal SOL EMG activity. CMC was computed in the time–frequency domain between the Cz EEG electrode signal and the unrectified SOL or MG EMG signal. Spinal excitability was quantified through normalized Hoffmann (H) reflex amplitude. The results indicate that beta-band CMC and normalized H-reflex were significantly lower in SOL during lengthening compared with isometric contractions, but were similar in MG for all three muscle contraction types. Collectively, these results highlight an effect of contraction type on beta-band CMC, although it may differ between agonist synergist muscles. These novel findings also provide new evidence that beta-band CMC modulation may involve spinal regulatory mechanisms.

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Acute Effects of Kinesiology Taping Stretch Tensions on Soleus and Gastrocnemius H-Reflex Modulations

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18094411 ◽

2021 ◽

Vol 18 (9) ◽

pp. 4411

Author(s):

Yung-Sheng Chen ◽

Shi Zhou ◽

Zachary J. Crowley-McHattan ◽

Pedro Bezerra ◽

Wei-Chin Tseng ◽

...

Keyword(s):

H Reflex ◽

Triceps Surae ◽

Reflex Modulation ◽

Hoffmann Reflex ◽

Acute Effects ◽

Physically Active ◽

M Wave ◽

Subject Design ◽

Minor Influence ◽

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This study examined the acute effects of stretch tensions of kinesiology taping (KT) on the soleus (SOL), medial (MG), and lateral (LG) gastrocnemius Hoffmann-reflex (H-reflex) modulation in physically active healthy adults. A cross-over within-subject design was used in this study. Twelve physically active collegiate students voluntarily participated in the study (age = 21.3 ± 1.2 years; height = 175.6 ± 7.1 cm; body weight = 69.9 ± 7.1 kg). A standard Y-shape of KT technique was applied to the calf muscles. The KT was controlled in three tension intensities in a randomised order: paper-off, 50%, and 100% of maximal stretch tension of the tape. The peak-to-peak amplitude of maximal M-wave (Mmax) and H-reflex (Hmax) responses in the SOL, MG, and LG muscles were assessed before taping (pre-taping), taping, and after taping (post-taping) phases in the lying prone position. The results demonstrated significantly larger LG Hmax responses in the pre-taping condition than those in the post-taping condition during paper-off KT (p = 0.002). Moreover, the ΔHmax/Mmax of pre- and post-taping in the SOL muscle was significantly larger during 50%KT tension than that of paper-off (p = 0.046). In conclusion, the stretch tension of KT contributes minor influence on the spinal motoneuron excitability in the triceps surae during rest.

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DOES VARYING THE AMPLITUDE OF THE SOLEUS H-REFLEX AFFECT THE GAIN?

Medicine & Science in Sports & Exercise ◽

10.1249/00005768-199505001-00967 ◽

1995 ◽

Vol 27 (Supplement) ◽

pp. S172

Author(s):

R. S. Phillips ◽

R. G. Mynark ◽

D. M. Koceja

Keyword(s):

H Reflex

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Long-lasting potentiation in the secondary somatosensory cortex affects motor control: Assessment by h-reflex

Neuroscience ◽

10.1016/0306-4522(96)00191-1 ◽

1996 ◽

Vol 74 (4) ◽

pp. 1125-1133 ◽

Cited By ~ 2

Author(s):

Y. Kawakami ◽

T. Oshima

Keyword(s):

Motor Control ◽

Somatosensory Cortex ◽

H Reflex ◽

Secondary Somatosensory Cortex

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Changes in H-reflex amplitude to muscle stretch and lengthening in humans

Reviews in the Neurosciences ◽

10.1515/revneuro-2016-0001 ◽

2016 ◽

Vol 27 (5) ◽

pp. 511-522 ◽

Cited By ~ 8

Author(s):

Francesco Budini ◽

Markus Tilp

Keyword(s):

Human Movement ◽

Careful Consideration ◽

H Reflex ◽

Spinal Reflex ◽

Neural Pathways ◽

Static Stretching ◽

Plantar Flexors ◽

Reflex Excitability ◽

Apparent Disagreement ◽

Shed Light

AbstractSpinal reflex excitability is traditionally assessed to investigate neural adjustments that occur during human movement. Different experimental procedures are known to condition spinal reflex excitability. Among these, lengthening movements and static stretching the human triceps have been investigated over the last 50 years. The purpose of this review is to shed light on several apparent incongruities in terms of magnitude and duration of the reported results. In the present review dissimilarities in neuro-spinal changes are examined in relation to the methodologies applied to condition and measure them. Literature that investigated three different conditioning procedures was reviewed: passive dorsiflexion, active dorsiflexion through antagonists shortening and eccentric plantar-flexors contractions. Measurements were obtained before, during and after lengthening or stretching. Stimulation intensities and time delays between conditioning procedures and stimuli varied considerably. H-reflex decreases immediately as static stretching is applied and in proportion to the stretch degree. During dorsiflexions the inhibition is stronger with greater dorsiflexion angular velocity and at lower nerve stimulation intensities, while it is weaker if any concomitant muscle contraction is performed. Within 2 s after a single passive dorsiflexion movement, H-reflex is strongly inhibited, and this effect disappears within 15 s. Dorsiflexions repeated over 1 h and prolonged static stretching training induce long-lasting inhibition. This review highlights that the apparent disagreement between studies is ascribable to small methodological differences. Lengthening movements and stretching can strongly influence spinal neural pathways. Results interpretation, however, needs careful consideration of the methodology applied.

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