Reciprocal Inhibition Research Articles

Comparison between the Effects of Reciprocal Inhibition technique Versus mulligan's straight Leg Raise with Distraction in Hamstring tightness on subjects with Chronic mechanical Low Back Pain

Comparison between the Effects of Reciprocal Inhibition technique Versus mulligan's straight Leg Raise with Distraction in Hamstring tightness on subjects with Chronic mechanical Low Back Pain

Short-term effects of electrical nerve stimulation on spinal reciprocal inhibition depend on gait phase during passive stepping

A combination of electrical nerve stimulation (ENS) and passive or active cyclic movements (i.e., pedaling and stepping) has been suggested to induce stronger short-term effects in spinal circuits as compared to either intervention alone. The purpose of the present study is to determine whether the effects of ENS during passive stepping are dependent on the timing of the stimulation during the stepping cycle. A total of 10 able-bodied participants were recruited for the study. Two interventions were assessed during passive ground stepping: (1) ENS of the common peroneal nerve (CPN) during the swing phase (ENSswing) and (2) stance phase (ENSstance). ENS was applied at the motor threshold intensity on the tibialis anterior muscle for a total of 30 min. Spinal reciprocal inhibition (RI) was assessed by conditioning the H-reflex in the soleus muscle with electrical stimulation to the CPN before (baseline), as well as 5, 15, and 30 min after each intervention. Compared to the baseline, the amount of RI was increased 5 and 15 min after the ENSswing intervention, whereas it was decreased after the ENSstance intervention. This suggests that ENS has a phase-dependent effect on RI during passive stepping. Overall, the results imply that phase-dependent timing of ENS is essential for guiding plasticity in the spinal circuits.

Coupling of Polo kinase activation to nuclear localization by a bifunctional NLS is required during mitotic entry

The Polo kinase is a master regulator of mitosis and cytokinesis conserved from yeasts to humans. Polo is composed of an N-term kinase domain (KD) and a C-term polo-box domain (PBD), which regulates its subcellular localizations. The PBD and KD can interact and inhibit each other, and this reciprocal inhibition is relieved when Polo is phosphorylated at its activation loop. How Polo activation and localization are coupled during mitotic entry is unknown. Here we report that PBD binding to the KD masks a nuclear localization signal (NLS). Activating phosphorylation of the KD leads to exposure of the NLS and entry of Polo into the nucleus before nuclear envelope breakdown. Failures of this mechanism result in misregulation of the Cdk1-activating Cdc25 phosphatase and lead to mitotic and developmental defects in Drosophila. These results uncover spatiotemporal mechanisms linking master regulatory enzymes during mitotic entry.

Relationship between spasticity and spinal neural circuits in patients with chronic hemiparetic stroke.

Spasticity is a common problem in patients with stroke that contributes to motor dysfunction. However, the pathophysiological mechanisms underlying spasticity are not fully understood. The purpose of the present study was to explain the relationship between features of spinal neural circuits assessed using electrophysiological techniques and the clinical manifestations of stroke. The participants were 71 patients with chronic hemiparetic stroke. To assess spinal neural circuits, Hmax/Mmax of the forearm flexor muscles and reciprocal inhibition (RI) between forearm extensor and flexor muscles with the H reflex conditioning-test paradigm were measured. The relationships between electrophysiological parameters and clinical variables (age, time from stroke onset, upper extremity functional scores, and spasticity) were then analyzed. It was found that the third phase of RI (RI-3) correlated with the modified Ashworth scores of the wrist and finger flexors. No other correlations were found between electrophysiological and clinical measures. These results suggest that RI-3 is associated with spasticity and may be helpful to understand the basis of post-stroke spasticity.

Treadmill Walking Combined With Anodal Transcranial Direct Current Stimulation in Parkinson Disease: A Pilot Study of Kinematic and Neurophysiological Effects.

We tested the hypothesis that combining treadmill walking with transcranial direct current stimulation (tDCS) enhances the gait improvements associated with treadmill walking in Parkinson disease. We explored the effects of these combined methodologies on corticospinal parameters. Eighteen participants with Parkinson disease were evaluated under the following three conditions: treadmill walking alone (treadmill), treadmill walking combined with anodal tDCS (AtDCS+treadmill) delivered over the motor cortex, and treadmill walking combined with sham stimulation (StDCS+treadmill). Overground walking performance, soleus H-reflex, reciprocal Ia inhibition from the tibialis anterior to the soleus muscle, intracortical facilitation, and short intracortical inhibition of the tibialis anterior muscle, were measured before and after each treadmill condition. The soleus H-reflex and walking performance on the treadmill were also evaluated. All treadmill conditions improved walking performance and modulated spinal and corticospinal parameters in a similar way. However, AtDCS+treadmill lead to a different modulation of reciprocal Ia inhibition in comparison with the other treadmill conditions. A single session combining treadmill walking and anodal tDCS delivered over the motor cortex resulted in a specific modulation of the reciprocal Ia inhibition from the tibialis anterior to the soleus muscle. However, this acute effect did not result in improvements of gait parameters associated with treadmill walking in Parkinson disease.

The Gastrointestinal Tract as an Integrator of Mechanical and Hormonal Response to Nutrient Ingestion.

Glucose tolerance after meal ingestion in vivo is the result of multiple processes that occur in parallel. Insulin secretion together with reciprocal inhibition of glucagon secretion contributes to glucose tolerance. However, other factors beyond glucose effectiveness and insulin action require consideration. The absorption of ingested nutrients and their subsequent systemic rate of appearance largely depend on the rate of delivery of nutrients to the proximal small intestine. This is determined by the integrated response of the upper gastrointestinal tract to a meal. While gastric emptying is probably the most significant component, other factors need to be considered. This review will examine all processes that could potentially alter the fraction and rate of appearance of ingested nutrients in the peripheral circulation. Several of these processes may be potential therapeutic targets for the prevention and treatment of diabetes. Indeed, there is increased interest in gastrointestinal contributions to nutritional homeostasis, as demonstrated by the advent of antidiabetes therapies that alter gastrointestinal motility, the effect of bariatric surgery on diabetes remission, and the potential of the intestinal microbiome as a modulator of human metabolism. The overall goal of this review is to examine current knowledge of the gastrointestinal contributions to metabolic control.

The Use of Hamstring Fatigue to Reduce Quadriceps Inhibition After Anterior Cruciate Ligament Reconstruction.

Arthrogenic muscle inhibition, an inability to fully activate the quadriceps muscles, has been persistently observed after anterior cruciate ligament reconstruction (ACLr) surgery. Reductions in quadriceps activation may be partly due to the flexion reflex pathway, hamstrings activation, and reciprocal quadriceps inhibition. Since central fatigue has been shown to modify hamstring excitability and change the hamstring reflex response, hamstring fatigue might alleviate quadriceps muscle inhibition by counteracting the flexion reflex. In this study, nine young adult athletes (age: M = 19.9 years, SD = 1.7) with unilateral ACLr and nine control athletes (age: M = 24.0 years, SD = 2.4) with no previous history of knee injury performed tempo squats to induce fatigue. The ACLr group tended to use hamstrings for more hip flexion and trunk forward flexion than the control group. We assessed each participant's quadriceps inhibition through the central activation ratio (CAR), measured by twitch interpolation, before and after the induced fatigue. A mixed analysis of variance was used to examine the effect of fatigue on the CAR between pre- and post-fatigue and for both ACLr and control groups. The ACLr group showed significantly ( p = .010) greater CAR of the quadriceps post-fatigue ( M = 96.0%, SD = 7.6%) than pre-fatigue ( M = 81.2%, SD = 15.8%), while the control group showed no significant ( p = .969) pre-fatigue ( M = 96.9%, SD = 9.6%) and post-fatigue ( M = 97.0%, SD = 17.1%) differences. Thus, fatigue training may be used as a rehabilitation strategy to restore normal quadriceps function at the knee joint following ACL reconstruction by relaxing the hamstrings and overcoming quadriceps inhibition.

State-dependent rhythmogenesis and frequency control in a half-center locomotor CPG.

The spinal locomotor central pattern generator (CPG) generates rhythmic activity with alternating flexion and extension phases. This rhythmic pattern is likely to result from inhibitory interactions between neural populations representing flexor and extensor half-centers. However, it is unclear whether the flexor-extensor CPG has a quasi-symmetric organization with both half-centers critically involved in rhythm generation, features an asymmetric organization with flexor-driven rhythmogenesis, or comprises a pair of intrinsically rhythmic half-centers. There are experimental data that support each of the above concepts but appear to be inconsistent with the others. In this theoretical/modeling study, we present and analyze a CPG model architecture that can operate in different regimes consistent with the above three concepts depending on conditions, which are defined by external excitatory drives to CPG half-centers. We show that control of frequency and phase durations within each regime depends on network dynamics, defined by the regime-dependent expression of the half-centers' intrinsic rhythmic capabilities and the operating phase transition mechanisms (escape vs. release). Our study suggests state dependency in locomotor CPG operation and proposes explanations for seemingly contradictory experimental data. NEW & NOTEWORTHY Our theoretical/modeling study focuses on the analysis of locomotor central pattern generators (CPGs) composed of conditionally bursting half-centers coupled with reciprocal inhibition and receiving independent external drives. We show that this CPG framework can operate in several regimes consistent with seemingly contradictory experimental data. In each regime, we study how intrinsic dynamics and phase-switching mechanisms control oscillation frequency and phase durations. Our results provide insights into the organization of spinal circuits controlling locomotion.

A Bitter Tale of Sweet Synergy

Some sweeteners show a synergistic enhancement of perceived sweetness when they are tasted as binary mixtures. In this issue of Cell Chemical Biology, Behrens etal. (2017) find that a surprising explanation for this classic observation may lie in their reciprocal inhibition of bitter taste receptors.

Prochlorperazine Increases KCC2 Function and Reduces Spasticity after Spinal Cord Injury.

In mature neurons, low intracellular chloride level required for inhibition is maintained by the potassium-chloride cotransporter, KCC2. Impairment of Cl- extrusion after KCC2 dysfunction has been involved in many central nervous system disorders, such as seizures, neuropathic pain, or spasticity, after a spinal cord injury (SCI). This makes KCC2 an appealing drug target for restoring Cl- homeostasis and inhibition in pathological conditions. In the present study, we screen the Prestwick Chemical Library® and identify conventional antipsychotics phenothiazine derivatives as enhancers of KCC2 activity. Among them, prochlorperazine hyperpolarizes the Cl- equilibrium potential in motoneurons of neonatal rats and restores the reciprocal inhibition post-SCI. The compound alleviates spasticity in chronic adult SCI rats with an efficacy equivalent to the antispastic agent, baclofen, and rescues the SCI-induced downregulation of KCC2 in motoneurons below the lesion. These pre-clinical data support prochlorperazine for a new therapeutic indication in the treatment of spasticity post-SCI and neurological disorders involving a KCC2 dysfunction.

Facile synthesis of SiO2@TiO2 crystallite photocatalysts with enhanced interaction level and high light absorption efficiency

SiO2@TiO2 crystallite photocatalysts with TiO2 crystallite core and porous amorphous SiO2/TiO2 shell were synthesized as photocatalyst by one-pot hydrothermal process using tetrabutyl titanate (TBOT) complex and ethyl orthosilicate (TEOS) as Ti and Si sources, respectively. The synthesized SiO2@TiO2 crystallite photocatalysts were characterized by transmission electron microscopy, X-ray diffraction pattern, UV–Vis diffuse reflectance spectrum and N2 adsorption–desorption isotherm. The interaction between TiO2 and SiO2, which is associated with photocatalytically active centers, is significantly improved through an enlargement in the interfacial area and the optimization of SiO2 fraction. The SiO2 modification does not lower the light absorption efficiency of TiO2 crystallite core owning to the low reflectivity of porous SiO2/TiO2 shell but endows the photocatalyst with easy separation behavior from aqueous solution. Furthermore, the reciprocal inhibition in volume shrinkage of TBOT complex- and TEOS-derived gel networks, as a consequence of mineralization asynchronism, increases the specific surface area and pore volume of the formed SiO2/TiO2 shell. The enhanced photocatalytic activity of SiO2@TiO2 crystallite photocatalysts by SiO2 modification is mainly ascribed to an increase in the interaction level, the high light absorption efficiency of SiO2@TiO2 crystallite photocatalysts and an enlargement in specific surface area of SiO2/TiO2 shell.

A reciprocal inhibition between ARID1 and MET1 in male and female gametes in Arabidopsis

Both female and male gametophytes harbor companion cells and gametes. MET1, a DNA methyltransferase, is down-regulated in companion cells. However, how MET1 is differentially regulated in gametophytes remains unexplored. ARID1, a transcription factor that is specifically depleted in sperm cells, is occupied by MET1-dependent CG methylation. Here, we show that MET1 confines ARID1 to the vegetative cell of male gametes, but ARID1 conversely represses MET1 in the central cell of female gametes. Compared to the vegetative cell-localization in wild type pollen, ARID1 expands to sperm cells in the met1 mutant. To understand whether MET1-dependent ARID1 inhibition exists during female gametogenesis, we first show that ARID1 is expressed in the megaspore mother cell (MMC), ARID1 but not MET1 is detectable in the central cell at maturity. Interestingly, compared to the absence of MET1 in the central cell and the egg cell of wild type ovules, MET1 significantly accumulates in these two cells in arid1 ovules. Lastly, we show that both ARID1 and MET1 are required for the cell specification of MMC. Collectively, our results uncover a reciprocal dependence between ARID1 and MET1, and provide a clue to further understand how the specification of MMC is likely regulated by DNA methylation.

O-2-6-15. Immediate effects of anodal tDCS combined with patterned electrical stimulation on gait performance in patients with stroke

Anodal transcranial direct current stimulation (tDCS) combined with patterned electrical stimulation (PES) modulates spinal reciprocal inhibition and improves the ankle movement in patients with incomplete spinal cord injury (Yamaguchi et al., 2016). This study aimed to examine the immediate effects of anodal tDCS combined with PES on gait performance in patients with stroke. Twelve patients with subacute stroke participated in this double-masked, sham-controlled cross-over study. They randomly participated in the following sessions on separate days: (1) anodal tDCS + PES; (2) anodal tDCS + sham PES; (3) sham tDCS + PES. The gait speed and surface electromyography (EMG) of tibialis anterior (TA) and soleus (SOL) muscles were measured before and after the intervention. As a result, the gait speed was not changed before and after the stimulation in all interventions. In anodal tDCS + PES condition, the EMG of the TA after the stimulation was significantly greater than that in the swing phase compared with other interventions. Anodal tDCS + PES produced significant improvement in the co-contraction ratio between TA and SOL after the stimulation, while other interventions produced no change. These findings suggest that anodal tDCS + PES could improve walking function in patients with stroke.

Tone-Inhibiting Insoles Enhance the Reciprocal Inhibition of Ankle Plantarflexors of Subjects With Hemiparesis After Stroke: An Electromyographic Study

BackgroundSpasticity is a common sequela of upper motor neuron pathology, such as cerebrovascular diseases and cerebral palsy. Intervention for spasticity of the ankle plantarflexors in physical therapy may include tone-inhibiting casting and/or orthoses for the ankle and foot. However, the physiological mechanism of tone reduction by such orthoses remains unclarified. ObjectiveTo investigate the electrophysiologic effects of tone-inhibiting insoles in stroke subjects with hemiparesis by measuring changes in reciprocal Ia inhibition (RI) in the ankle plantarflexor. DesignAn interventional before–after study. SettingAcute stroke unit or ambulatory rehabilitation clinic of a university hospital in Japan. ParticipantsTen subjects (47-84 years) with hemiparesis and 10 healthy male control subjects (31-59 years) were recruited. MethodsRI of the spastic soleus in response to the electrical stimulation of the deep peroneal nerve was evaluated by stimulus-locked averaging of rectified electromyography (EMG) of the soleus while subjects were standing. Main Outcome MeasurementsThe magnitude of RI, defined as the ratio of the lowest to the baseline amplitude of the rectified EMG at approximately 40 milliseconds after stimulation, was measured while subjects were standing with and without the tone-inhibiting insole on the hemiparesis side. ResultsEnhancement of EMG reduction with the tone-inhibiting insole was significant (P < .05) in the subjects with hemiparesis, whereas no significant changes were found in controls. ConclusionTone-inhibiting insoles enhanced RI of the soleus in subjects after stroke, which might enhance standing stability by reducing unfavorable ankle plantarflexion tone. Level of EvidenceIII

Bacterial production and reconstitution in proteoliposomes of Solanum lycopersicum CAT2: a transporter of basic amino acids and organic cations.

The vacuolar SlCAT2 was cloned, over-produced in E. coli and reconstituted in proteoliposomes. Arg, Ornithine and Lys were identified as substrates. Unexpectedly, also the organic cations Tetraethylammonium and Acetylcholine were transported indicating involvement of SlCAT2 in signaling. In land plants several transporters are involved in ion and metabolite flux across membranes of cells or intracellular organelles. The vacuolar amino acid transporter CAT2 from Solanum lycopersicum was investigated in this work. SlCAT2 was cloned from tomato flower cDNA, over-produced in Escherichia coli and purified by Nichel-chelating chromatography. For functional studies, the transporter was reconstituted in proteoliposomes. Competence of SlCAT2 for Arg transport was demonstrated measuring uptake of [3H]Arg in proteoliposomes which was trans-stimulated by internal Arg or ornithine. Uptake of [3H]Ornithine and [3H]Lys was also detected at lower efficiency with respect to [3H]Arg. Transport was activated by the presence of intraliposomal ATP suggesting regulation by the nucleotide. The prototype for organic cations tetraethylammonium (TEA) was also transported by SlCAT2. However, scarce reciprocal inhibition between TEA and Arg was found, while the biguanide metformin was able to strongly inhibit uptake of both substrates. These findings suggest that amino acids and organic cations may interact with the transporter through different functional groups some of which are common for the two types of substrates. Interestingly, reconstituted SlCAT2 showed competence for acetylcholine transport, which was also inhibited by metformin. Kinetics of Arg and Ach transport were performed from which Km values of 0.29 and 0.79mM were derived, respectively.

EFFECT OF POST-ISOMETRIC RELAXATION AND RECIPROCAL INHIBITION IN OSTEOARTHRITIS KNEE

Objectives : To evaluateeffect of post-isometric relaxation, reciprocal inhibition andcombined effect post-isometric relaxation and reciprocal inhibition in osteoarthritis knee.Method :Ethical clearance was obtained from Institutional Ethical Committee, KIMSDU karad. Comparative study conducted at Physiotherapy Dept. of Krishna Institute of medical sciences. A total of 30 subjectswere equally divided into three groups using Convenientsampling with random allocation(Group A,Group B and Group C).Baseline treatment was given to all three groups(IFT and HMP). Group A was given post-isometric relaxation, Group B was given reciprocal inhibition and Group C was given combination of post-isometric relaxation and reciprocal inhibition. Result: Statistical analysis was done using paired t test and ANOVA test. Inpre intervention there was no statistical significant difference seen with p values for VAS of 0.3408 and for WOMAC of 0.5424. While on comparing the post interventional values, the results between the three Groups using ANOVA test revealed that there was very significant difference seen with p value for VAS of 0.0023 and for WOMAC of 0.0019.Conclusion: From the study it can be concluded thatthere was significant effect of post-isometric relaxation and reciprocal inhibition in OA knee.

Role of the locus coeruleus in the emergence of power law wake bouts in a model of the brainstem sleep-wake system through early infancy

Infant rats randomly cycle between the sleeping and waking states, which are tightly correlated with the activity of mutually inhibitory brainstem sleep and wake populations. Bouts of sleep and wakefulness are random; from P2–P10, sleep and wake bout lengths are exponentially distributed with increasing means, while during P10–P21, the sleep bout distribution remains exponential while the distribution of wake bouts gradually transforms to power law. The locus coeruleus (LC), via an undeciphered interaction with sleep and wake populations, has been shown experimentally to be responsible for the exponential to power law transition. Concurrently during P10–P21, the LC undergoes striking physiological changes – the LC exhibits strong global 0.3 Hz oscillations up to P10, but the oscillation frequency gradually rises and synchrony diminishes from P10–P21, with oscillations and synchrony vanishing at P21 and beyond. In this work, we construct a biologically plausible Wilson Cowan-style model consisting of the LC along with sleep and wake populations. We show that external noise and strong reciprocal inhibition can lead to switching between sleep and wake populations and exponentially distributed sleep and wake bout durations as during P2–P10, with the parameters of inhibition between the sleep and wake populations controlling mean bout lengths. Furthermore, we show that the changing physiology of the LC from P10–P21, coupled with reciprocal excitation between the LC and wake population, can explain the shift from exponential to power law of the wake bout distribution. To our knowledge, this is the first study that proposes a plausible biological mechanism, which incorporates the known changing physiology of the LC, for tying the developing sleep-wake circuit and its interaction with the LC to the transformation of sleep and wake bout dynamics from P2–P21.

The effects of patterned electrical stimulation combined with voluntary contraction on spinal reciprocal inhibition in healthy individuals

The aim of this study was to examine the effects of voluntary contraction (VC) on the modulation of reciprocal inhibition induced by patterned electrical stimulation (PES) in healthy individuals. Twelve healthy volunteers participated in this study. PES was applied to the common peroneal nerve with a train of 10 pulses at 100 Hz every 2 s for 20 min. VC comprised repetitive ankle dorsiflexion at a frequency of 0.5 Hz for 20 min. All participants performed the following three tasks: (i) VC alone, (ii) PES alone, and (iii) PES combined with VC (PES+VC). Reciprocal inhibition was assessed using a soleus H-reflex conditioning-test paradigm at the time points of before, immediately after, 10 min after, 20 min after, and 30 min after the tasks. PES+VC increased the amount of reciprocal inhibition, with after-effects lasting up to 20 min. PES alone increased reciprocal inhibition and maintained the after-effects on reciprocal inhibition for 10 min, whereas VC alone increased only immediately after the task. VC could modulate the plastic changes in spinal reciprocal inhibition induced by PES in healthy individuals. PES combined with VC has a potential to modulate impaired reciprocal inhibition and it may facilitate functional recovery and improve locomotion after central nervous system lesions.

Variations on a theme: species differences in synaptic connectivity do not predict central pattern generator activity.

A fundamental question in comparative neuroethology is the extent to which synaptic wiring determines behavior vs. the extent to which it is constrained by phylogeny. We investigated this by examining the connectivity and activity of homologous neurons in different species. Melibe leonina and Dendronotus iris (Mollusca, Gastropoda, Nudibranchia) have homologous neurons and exhibit homologous swimming behaviors consisting of alternating left-right (LR) whole body flexions. Yet, a homologous interneuron (Si1) differs between the two species in its participation in the swim motor pattern (SMP) and synaptic connectivity. In this study we examined Si1 homologs in two additional nudibranchs: Flabellina iodinea, which evolved LR swimming independently of Melibe and Dendronotus, and Tritonia diomedea, which swims with dorsal-ventral (DV) body flexions. In Flabellina, the contralateral Si1s exhibit alternating rhythmic bursting activity during the SMP and are members of the swim central pattern generator (CPG), as in Melibe The Si1 homologs in Tritonia do not burst rhythmically during the DV SMP but are inhibited and receive bilaterally synchronous synaptic input. In both Flabellina and Tritonia, the Si1 homologs exhibit reciprocal inhibition, as in Melibe However, in Flabellina the inhibition is polysynaptic, whereas in Tritonia it is monosynaptic, as in Melibe In all species, the contralateral Si1s are electrically coupled. These results suggest that Flabellina and Melibe convergently evolved a swim CPG that contains Si1; however, they differ in monosynaptic connections. Connectivity is more similar between Tritonia and Melibe, which exhibit different swimming behaviors. Thus connectivity between homologous neurons varies independently of both behavior and phylogeny.NEW & NOTEWORTHY This research shows that the synaptic connectivity between homologous neurons exhibits species-specific variations on a basic theme. The neurons vary in the extent of electrical coupling and reciprocal inhibition. They also exhibit different patterns of activity during rhythmic motor behaviors that are not predicted by their circuitry. The circuitry does not map onto the phylogeny in a predictable fashion either. Thus neither neuronal homology nor species behavior is predictive of neural circuit connectivity.

Особенности спинального торможения при произвольной двигательной активности мышц голени у лиц, занимающихся физической культурой и спортом

Objective: the purpose of the research was to study of different types of spinal inhibition when performing voluntary movements in persons doing increasing intensity graded physical exercises sports. Materials and methods: 45 male took part in the research. Presynaptic inhibition of Ia afferents of soleus was evaluated using the technique of Y. Mizuno et al., nonreciprocal inhibition of α-motoneurons - by E. Pierrot-Deseilligny et al, and reciprocal inhibition of α-motoneurons - by C. Crone et al., in the state of relative muscular rest and during a 30-second isometric contraction with a force of 25% maximum voluntary contraction (MVC) using the multijoint medical-diagnostic complex «Biodex». Results: it was established that weakening of inhibitory processes occurred in comparison with the state of relative muscular rest in the course of a 30-second isometric contraction; this pattern is related to the specificity of supraspinal excitatory and inhibitory effects on Ia and Ib interneurons in the spinal cord when performing a voluntary movement. The voluntary movement performed for 30 seconds was accompanied by an increased activity of the presynaptic inhibition of Ia afferents of foot flexor, unlike reciprocal and nonreciprocal inhibition. Conclusions: the voluntary movement presynaptic inhibition must be actively regulating the excess afferent input to α-motoneurons of agonist and antagonist lower leg muscles, accelerating nonreciprocal and reciprocal inhibitory effects rendered on them, providing normal motor activity in man. New data derived from such research can be a theoretical basis for the study of physiological patterns of involvement of cortical and spinal neuronal inhibition networks underlying motor tasks of different complexity in athletes.