Comparative study of observed actions,motor imagery and control therapeutic exercise on the conditioned pain modulation in the cervical spine: a randomized controlled trial

Abstract

Aim: The aim of this study was to compare the effects of cervical exercise, motor imagery (MI) and action observation (AO) of cervical exercise actions on conditioned pain modulation and pressure pain thresholds. The second objective was to assess the effects of these interventions on cervical motor activity (ranges of motion and muscle endurance), attention, and the ability to generate motor images.

Study design: Single-blinded randomized controlled trial.

Materials and methods: Fifty-four healthy subjects were randomly assigned to each group. Response conditioned pain modulation, pressure pain threshold, were the main variables. The secondary outcome measures included, cervical range of motion, Neck flexor endurance test, mental movement representation associated and psychosocial variables.

Results: All groups showed significant differences in time factor for all evaluated variables (p?<?.01) except pressure pain threshold over the tibial region. The post hoc analysis revealed significant within-group differences in the AE and AO groups in conditioned pain modulation (p?<?.05), with medium effect size in time [AE (d –0.61); AO (d –0.74)].

Conclusion: The results showed that within-group changes in conditioned pain modulation, cervical muscle endurance, and attention where founded only in the AE and AO groups. Variations in pain thresholds at pressure in the trapezium area were also obtained in the three groups. Changes in the ranges of flexion-extension and rotation movement were presented exclusively in the exercise group, and in the capacity to generate motor images only in the AO group. However, there was no difference in the pressure pain threshold over the tibial region.     

Visual motor imagery predominance in professional Spanish dancers

Abstract

Purpose: The main objectives of the study were to analyse the predominant motor imagery modality used by professional Spanish dancers and to compare Spanish dancers’ ability to perform mental motor imagery with that of non-dancers, and to analyse differences between male and female dancers. As a secondary aim, to compare the motor imagery ability between two styles of Spanish dance: classical Spanish dancers and Flamenco dancers.

Methods: A total of 74 participants were classified into two groups: professional Spanish dancers (n?=?37) and sedentary participants (n?=?37). The professional Spanish dancer group was composed of two dance disciplines: flamenco dancers (n?=?17), and classical dancers (n?=?20).

Results: Professional Spanish dancers used predominantly visual imagery modalities over kinesthetics to generate motor imagery, with a moderate effect size (p?<?.01, d?=?0.68). Regarding the ability to generate motor imagery, significant intergroup differences between professional Spanish dancers and sedentary participants were observed in all variables, with a large effect size (p?<?.05, d?>?0.80). Differences were obtained between men and women among non-dancers group (t?=??3.34; p?=?.03; d?=?0.5). No differences between Flamenco and classical dancers were observed.

Conclusion: Visual motor imagery modality was easier than the kinaesthetic modality in the generation of motor imagery for professional Spanish dancers regardless of the dance style. Spanish dancers had a greater ability to perform motor imagery compared with non-dancer individuals, needing less time to perform these mental tasks. Men non-dancers had a greater ability to generate motor imagery than women. Reinforcing the training of kinaesthetic motor imagery might be useful for professional Spanish dancers.     

Influence of motor imagery of isometric flexor hallucis brevis activity on the excitability of spinal neural function

Purpose: This study aimed to validate the preliminary steps of motor image voluntary training in patients who are prone to falling as toe flexion muscle strength decreases.

Materials and methods: We recorded the F-wave in 30 healthy subjects (20 men, 10 women; mean age, 22.5?±?2.1?years). First, in a resting condition, the muscle was relaxed during the F-wave recording. Subsequently, the motion of the left flexor hallucis brevis muscle is photographed. F-waves were recorded immediately and at 5, 10, and 15?min after motor imagery. The amplitude of the F/M ratio and persistence were measured. The intervention group watched the exercise task video used for F-wave measurement daily for 1?month, whereas the non-intervention group did not. The second measurement was performed 1?month later in each group.

Results: In the first measurement of the amplitude of the F/M ratio in both intervention and non-intervention groups, the image condition was significantly increased compared with the resting condition, but there was no significant difference in persistence. A significant decrease in the amplitude of the F/M ratio after image conditioning was observed in the second measurement of the intervention group.

Conclusion: Although spinal nerve function excitement was enhanced during motor imagery, movement suppression was promoted, and spinal nerve excitability was suppressed when repeating the simple task. In the future, gradually upscaling the difficulty level of the toe flexion motor task used in the motor image may be necessary to prevent falls.     

Cerebral haemodynamics during motor imagery of self-feeding with chopsticks: differences between dominant and non-dominant hand

Abstract

Purpose: Motor imagery is defined as a dynamic state during which a subject mentally simulates a given action without overt movements. Our aim was to use near-infrared spectroscopy to investigate differences in cerebral haemodynamics during motor imagery of self-feeding with chopsticks using the dominant or non-dominant hand.

Materials and methods: Twenty healthy right-handed people participated in this study. The motor imagery task involved eating sliced cucumber pickles using chopsticks with the dominant (right) or non-dominant (left) hand. Activation of regions of interest (pre-supplementary motor area, supplementary motor area, pre-motor area, pre-frontal cortex, and sensorimotor cortex was assessed.

Results: Motor imagery vividness of the dominant hand tended to be significantly higher than that of the non-dominant hand. The time of peak oxygenated haemoglobin was significantly earlier in the right pre-frontal cortex than in the supplementary motor area and left pre-motor area. Haemodynamic correlations were detected in more regions of interest during dominant-hand motor imagery than during non-dominant-hand motor imagery.

Conclusions: Haemodynamics might be affected by differences in motor imagery vividness caused by variations in motor manipulation.     

Somatosensory cortex excitability changes due to differences in instruction conditions of motor imagery

Purpose Vivid motor imagery appears to be associated with improved motor learning efficiency. However, the practical difficulties in measuring vivid motor imagery warrant new analytical approaches. The present study aimed to determine the instruction conditions for which vividness in motor imagery could be more easily seen and the excitability of the sensory cortex as it relates to the motor image. Materials and methods In total, 15 healthy, right-handed volunteers were instructed to imagine grasping a rubber ball under a verbal-only instruction condition (verbal condition), a verbal?+?visual instruction condition (visual condition), and a verbal?+?execution (physically grasping a real ball) condition (execution condition). We analyzed motor imagery-related changes in somatosensory cortical excitability by comparing somatosensory-evoked potentials in each condition with the rest (control) condition. We also used a visual analogue scale to measure subject-reported vividness of imagery. Results We found the N33 component was significantly lower in the execution condition than in the rest condition (p?Conclusions These data suggest that experiencing a movement through actual motor execution immediately prior to performing mental imagery of that movement enhances the excitability of motor-related cortical areas. It is suggested that the excitability of the motor-related region increased as a result of the motor imagery in the execution condition acting on the corresponding somatosensory cortex.     

Organization of meissner corpuscles in the glabrous skin of monkey and cat

Abstract

Purpose: Motor imagery, the process of imagining a physical action, has been shown to facilitate the excitability of spinal anterior horn cells. In the acute phase after a stroke, the excitability of spinal anterior horn cells is significantly reduced, which leads to motor deficits. This loss of movement can be prevented by increasing the excitability of spinal anterior horn cells immediately following an injury. Motor imagery is an effective method for facilitating the excitability of spinal anterior horn cells in patients with impaired movement; however, the optimal duration for motor imagery is unclear.

Materials and Methods: To investigate time-dependent changes in spinal anterior horn cell excitability during motor imagery, healthy adult participants were recruited to measure the F-wave, an indicator of anterior horn cell excitability. F-waves were measured from participants at baseline, during motor imagery, and post-motor imagery. During motor imagery, participants imagined isometric thenar muscle activity at 50% maximum voluntary contraction for 5?min. F-waves were measured at 1, 3, and 5?min after beginning motor imagery and analysed for persistence and F/M amplitude ratio.

Results: Persistence and F/M amplitude ratios at 1- and 3-min after motor imagery initiation were significantly greater than at baseline. The persistence and F/M amplitude ratio at 5-min after motor imagery initiation, however, was comparable to baseline levels.

Conclusion: Therefore, 1 to 3?min of motor imagery is likely sufficient to facilitate the excitability of spinal anterior horn cells.     

What are the determinants of explicit and implicit motor imagery ability in stroke patients?: a controlled study

Abstract

Purpose: The purposes of the study were to (a) investigate both explicit and implicit motor imagery ability (MIA) impairment after stroke, (b) examine predictive effects of clinical characteristics for MIA after stroke.

Materials and Methods: Forty one patients with stroke (PwS) (mean age 59.41?±?10.19?years; %41 female) and 36 healthy participants (mean age 62.47?±?9.29?years; %47 female) completed Chaotic Motor Imagery Assessment-Hand Rotation for implicit MIA and Movement Imagery Questionnaire-3 (MIQ-3) and Box and Block Test (BBT) for explicit MIA. The severity of motor and sensory impairments were determined by the Fugl-Meyer Assessment-Upper Extremity (FMAUE) scores. The Turkish version of Motor Activity Log-28 was used to assess amount of use (AUS) and quality of movement in daily life.

Results: Our results indicated that both implicit and explicit MIA (except kinaesthetic imagery of MIQ-3) in PwS were statistically impaired compared to controls (p?<?0.05). The sensorimotor impairment level, amount of use and movement quality of the affected upper limb were found to be correlated with MIA in various degrees. Total motor scores in FMAUE and AUS were significant predictors of explicit MIA (p?<?0.01). Additionally, explicit MIA scores of stroke subgroups were statistically different between severely and mildly impaired patients, in favour of mildly impaired group (p?<?0.05).

Conclusion: In conclusion, both motor impairment level and amount of daily use of upper extremity were found to be predictive factors for explicit MIA. Further investigation with brain imaging techniques is needed to explore the validity of these findings in establishing MIA.     

Effects of low-frequency repetitive transcranial magnetic stimulation on upper extremity motor recovery and functional outcomes in chronic stroke patients: A randomized controlled trial

Background: Repetitive transcranial magnetic stimulation (rTMS) was suggested as a preconditioning method that would increase brain plasticity and that it would be optimal to combine rTMS with intensive rehabilitation.

Objective: To assess the efficacy of inhibitory rTMS on upper extremity motor recovery and functional outcomes in chronic ischemic stroke patients.

Methods: In this randomized controlled trial, experimental group received low-frequency (LF) rTMS to the primary motor cortex of the unaffected side?+?physical therapy (PT), and control group received PT.

Results: No statistically significant difference was found in baseline demographical and clinical characteristics of the subjects including stroke severity or severity of paralysis prior to intervention. There were statistically significant improvements in all clinical outcome measures except for the Brunnstrom Recovery Stages. Fugl–Meyer Assessment, Box and Block test, motor and total scores of Functional Independence Measurement (FIM), and Functional Ambulation Scale (FAS) scores were significantly increased in both groups, however, these changes were significantly greater in the rTMS group except for FAS score. FIM cognitive scores and standardized mini-mental test scores were significantly increased and distal and hand Modified Ashworth Scale scores were significantly decreased only in the rTMS group (p?Conclusions: LF-rTMS can safely facilitate upper extremity motor recovery in patients with chronic ischemic stroke. TMS seems to be a promising treatment for motor, functional, and cognitive deficits in chronic stroke. Further studies with a larger number of patients with longer follow-up periods are needed to establish its effectiveness in stroke rehabilitation.     

Excitability of the Primary Motor Cortex Increases More Strongly with Slow- than with Normal-Speed Presentation of Actions

Introduction

The aim of the present study was to investigate how the speed of observed action affects the excitability of the primary motor cortex (M1), as assessed by the size of motor evoked potentials (MEPs) induced by transcranial magnetic stimulation (TMS).

Methods

Eighteen healthy subjects watched a video clip of a person catching a ball, played at three different speeds (normal-, half-, and quarter-speed). MEPs were induced by TMS when the model''s hand had opened to the widest extent just before catching the ball (“open”) and when the model had just caught the ball (“catch”). These two events were locked to specific frames of the video clip (“phases”), rather than occurring at specific absolute times, so that they could easily be compared across different speeds. MEPs were recorded from the thenar (TH) and abductor digiti minimi (ADM) muscles of the right hand.

Results

The MEP amplitudes were higher when the subjects watched the video clip at low speed than when they watched the clip at normal speed. A repeated-measures ANOVA, with the factor VIDEO-SPEED, showed significant main effects. Bonferroni''s post hoc test showed that the following MEP amplitude differences were significant: TH, normal vs. quarter; ADM, normal vs. half; and ADM, normal vs. quarter. Paired t-tests showed that the significant MEP amplitude differences between TMS phases under each speed condition were TH, “catch” higher than “open” at quarter speed; ADM, “catch” higher than “open” at half speed.

Conclusions

These results indicate that the excitability of M1 was higher when the observed action was played at low speed. Our findings suggest that the action observation system became more active when the subjects observed the video clip at low speed, because the subjects could then recognize the elements of action and intention in others.     

MOTOmed下肢运动训练联合等速肌力训练对脑卒中偏瘫患者下肢运动功能、下肢肌张力和步行步态功能的影响

摘要 目的：观察MOTOmed下肢运动训练联合等速肌力训练在脑卒中偏瘫患者的应用价值。方法：根据随机数字表法将2019年5月-2022年12月期间南京医科大学附属脑科医院收治的158例脑卒中偏瘫患者分为对照组（n=79,接受等速肌力训练）和观察组（n=79,对照组基础上接受MOTOmed下肢运动训练）。对比两组下肢运动功能、下肢肌张力、步行步态功能。结果：干预12周后,两组Fugl-Meyer运动功能评定量表（FMA）、Berg平衡量表（BBS）评分升高,且观察组高于对照组同期（P<0.05）。干预12周后,两组膝关节后伸（FKE）、前屈（FKF）、髋关节后伸（FHE）、前屈（FHF） 肌张力升高,且观察组高于对照组同期（P<0.05）。干预12周后,两组步速、步频、步长、功能性步行分级量表（FAC）评分升高,且观察组高于对照组同期（P<0.05）。结论：MOTOmed下肢运动训练联合等速肌力训练治疗脑卒中偏瘫患者,可有效改善下肢运动功能、下肢肌张力以及步行步态功能。     

Different motor learning effects on excitability changes of motor cortex in muscle contraction state

Abstract

We aimed to investigate whether motor learning induces different excitability changes in the human motor cortex (M1) between two different muscle contraction states (before voluntary contraction [static] or during voluntary contraction [dynamic]). For the same, using motor evoked potentials (MEPs) obtained by transcranial magnetic stimulation (TMS), we compared excitability changes during these two states after pinch-grip motor skill learning. The participants performed a force output tracking task by pinch grip on a computer screen. TMS was applied prior to the pinch grip (static) and after initiation of voluntary contraction (dynamic). MEPs of the following muscles were recorded: first dorsal interosseous (FDI), thenar muscle (Thenar), flexor carpi radialis (FCR), and extensor carpi radialis (ECR) muscles. During both the states, motor skill training led to significant improvement of motor performance. During the static state, MEPs of the FDI muscle were significantly facilitated after motor learning; however, during the dynamic state, MEPs of the FDI, Thenar, and FCR muscles were significantly decreased. Based on the results of this study, we concluded that excitability changes in the human M1 are differentially influenced during different voluntary contraction states (static and dynamic) after motor learning.     

The severity of chewing disorders is related to gross motor function and trunk control in children with cerebral palsy

Abstract

Purpose: The frequency of chewing disorders increases with decreasing level of gross motor function in children with cerebral palsy (CP). Besides its frequency, the severity of chewing disorders is also important. The aim of this study was to determine the relationship between chewing performance level and gross motor function, and trunk postural control in children with CP.

Materials and methods: The study included 119 children with CP (age 2–10 years). Chewing performance level was determined by the Karaduman Chewing Performance Scale (KCPS). The Gross Motor Function Classification System (GMFCS) was used to determine the level of gross motor function. Segmental Assessment of Trunk Control (SATCo) was used to measure trunk control.

Results: Children with spastic CP with a median age of 4?years were evaluated, of which 50.4% were male. The percentages of patients classified to GMFCS levels I to V were 43.7%, 6.7%, 9.2%, 5.0%, and 35.3%, respectively. The median KCPS score was 3 (min?=?0, max?=?4). A good correlation was found between KCPS and GMFCS (p?<?.001, r?=?0.70). Negative, excellent correlations between KCPS and SATCo static, SATCo active, and SATCo reactive postural controls were found (p?<?.001, r?=?–0.75, r?=?–0.77, r?=?–0.79; respectively).

Conclusions: The severity of chewing disorders is related to the level of gross motor function and trunk postural control in children with CP.

Clinical trial number: NCT03241160     

肌内效贴镇痛联合康复训练对脑卒中偏瘫患者下肢运动功能、步行参数和生活质量的影响

目的:探讨肌内效贴镇痛联合康复训练对脑卒中偏瘫患者下肢运动功能、步行参数和生活质量的影响。方法:选取2017年1月-2018年1月期间我院收治的脑卒中偏瘫患者200例为研究对象。根据随机数表法将患者分为对照组(n=100)与观察组(n=100)。两组患者均接受常规康复训练,观察组在此基础上联合肌内效贴镇痛治疗。两组均治疗4周,观察并比较两组患者治疗前后下肢运动功能、步行参数和生活质量。结果:两组患者治疗后简化Fugl-Meyer运动功能量表(FMA-L)、徒手肌力测试(MMT)、Berg平衡量表(BBS)均较治疗前升高,且观察组高于对照组(P0.05);两组患者治疗后改良Ash-worth量表(MAS)、计时起立行走测试(TGUT)均较治疗前降低,且观察组低于对照组(P0.05)。两组患者治疗后步速、步幅、患侧步长、健侧步长、步态周期、双腿支撑期均较治疗前升高,且观察组高于对照组(P0.05);两组患者治疗后步态不对称指数较治疗前降低,且观察组低于对照组(P0.05)。两组患者治疗后Barthel指数(BI)较治疗前升高,且观察组高于对照组(P0.05)。结论:肌内效贴镇痛与康复训练联合治疗脑卒中偏瘫患者,疗效满意,可显著改善患者下肢运动功能、步行参数以及生活质量。     

Active Vision during Action Execution,Observation and Imagery: Evidence for Shared Motor Representations

The concept of shared motor representations between action execution and various covert conditions has been demonstrated through a number of psychophysiological modalities over the past two decades. Rarely, however, have researchers considered the congruence of physical, imaginary and observed movement markers in a single paradigm and never in a design where eye movement metrics are the markers. In this study, participants were required to perform a forward reach and point Fitts’ Task on a digitizing tablet whilst wearing an eye movement system. Gaze metrics were used to compare behaviour congruence between action execution, action observation, and guided and unguided movement imagery conditions. The data showed that participants attended the same task-related visual cues between conditions but the strategy was different. Specifically, the number of fixations was significantly different between action execution and all covert conditions. In addition, fixation duration was congruent between action execution and action observation only, and both conditions displayed an indirect Fitts’ Law effect. We therefore extend the understanding of the common motor representation by demonstrating, for the first time, common spatial eye movement metrics across simulation conditions and some specific temporal congruence for action execution and action observation. Our findings suggest that action observation may be an effective technique in supporting motor processes. The use of video as an adjunct to physical techniques may be beneficial in supporting motor planning in both performance and clinical rehabilitation environments.     

The comparison of motor learning performance with and without feedback

Ten individuals were divided into two feedback and no-feedback groups. The effect of abstract visual feedback was investigated in these two groups. Using eight electroencephalography (EEG) electrodes, the induced event-related desynchronization/synchronization of the EEG of three motor imagery tasks (left hand, right hand, and right foot) was analyzed by wavelet and spatial filtering methods. Linear discriminant analysis was used to classify the three imagery tasks. Each imagery task's total length was set to 3?s and 1?s of it was used for the classification. The classification result was shown to the subjects of the feedback group in a real-time manner as an abstract visual feedback. While the paired t-test of the first and third sessions of the training days confirmed the improvement of the motor imagery learning in the feedback group (p?<?0.01), the motor imagery learning of the no-feedback group was not significant.     

Motor Imagery in Asperger Syndrome: Testing Action Simulation by the Hand Laterality Task

Asperger syndrome (AS) is a neurodevelopmental condition within the Autism Spectrum Disorders (ASD) characterized by specific difficulties in social interaction, communication and behavioural control. In recent years, it has been suggested that ASD is related to a dysfunction of action simulation processes, but studies employing imitation or action observation tasks provided mixed results. Here, we addressed action simulation processes in adolescents with AS by means of a motor imagery task, the classical hand laterality task (to decide whether a rotated hand image is left or right); mental rotation of letters was also evaluated. As a specific marker of action simulation in hand rotation, we assessed the so-called biomechanical effect, that is the advantage for judging hand pictures showing physically comfortable versus physically awkward positions. We found the biomechanical effect in typically-developing participants but not in participants with AS. Overall performance on both hand laterality and letter rotation tasks, instead, did not differ in the two groups. These findings demonstrated a specific alteration of motor imagery skills in AS. We suggest that impaired mental simulation and imitation of goal-less movements in ASD could be related to shared cognitive mechanisms.     

经颅直流电刺激干预联合康复训练对痉挛型脑瘫患儿精细运动功能的影响

摘要 目的：探究经颅直流电刺激干预联合康复训练对痉挛型脑瘫患儿精细运动功能的影响。方法：选取2020年7月至2022年6月在我院儿童康复科收治的痉挛型脑瘫患儿116例为研究对象,按随机数字表法将患儿随机分为观察组、对照组,每组58例,对照组采用常规康复训练,观察组在对照组的基础上采用tDCS治疗。采用采用关节活动度量角器测定腕关节背伸关节活动度(AROM) ,采用脑瘫患儿精细运动功能测试量表（FMFM）评估患儿的双上肢精细操作能力,采用Peabody 精细运动发育量表(PDMS-FM)评定双手精细运动功能,采用改良Ashworth肌张力评定量表(MAS)评估患儿患侧上肢肘关节肌张力状况,比较两组治疗前后的各项指标差异变化。结果：治疗后两组患儿AROM评分较治疗前均显著增加,且观察组AROM评分显著高于对照组,差异具有统计学意义（P＜0.05）。治疗后两组患儿FMFM评分较治疗前均显著增加,且观察组FMFM评分显著高于对照组,差异具有统计学意义（P＜0.05）。治疗后两组患儿FMQ评分较治疗前均显著增加,且观察组FMQ评分显著高于对照组,差异具有统计学意义（P＜0.05）。治疗后两组患儿MAS评分较治疗前均显著降低,且观察组MAS评分显著低于对照组,差异具有统计学意义（P＜0.05）。结论：经颅直流电刺激干预联合康复训练可以显著改善痉挛型脑瘫患儿腕关节背伸关节活动度、双上肢精细操作能力、双手精细运动功能和患侧上肢肘关节肌张力,对精细运动功能具有改善作用。     

Prediction of lower limb motor outcomes based on transcranial magnetic stimulation findings in patients with an infarct of the anterior cerebral artery

Abstract

The aim was to investigate the relationship between transcranial magnetic stimulation (TMS) at the early stage of stroke and 6-month motor outcome for patients with anterior cerebral artery territory infarct. Patients were classified into TMS(+) and TMS(?) groups. At the 6-month evaluation, lower limb motor function for the TMS(+) group was significantly better than those for the TMS(?) group. Thus, early TMS evaluation is useful for predicting recovery of lower limb motor function in patients experiencing this type of stroke.     

The Influence of Mirror-Visual Feedback on Training-Induced Motor Performance Gains in the Untrained Hand

The well-documented observation of bilateral performance gains following unilateral motor training, a phenomenon known as cross-limb transfer, has important implications for rehabilitation. It has recently been shown that provision of a mirror image of the active hand during unilateral motor training has the capacity to enhance the efficacy of this phenomenon when compared to training without augmented visual feedback (i.e., watching the passive hand), possibly via action observation effects [1]. The current experiment was designed to confirm whether mirror-visual feedback (MVF) during motor training can indeed elicit greater performance gains in the untrained hand compared to more standard visual feedback (i.e., watching the active hand). Furthermore, discussing the mechanisms underlying any such MVF-induced behavioural effects, we suggest that action observation and the cross-activation hypothesis may both play important roles in eliciting cross-limb transfer. Eighty participants practiced a fast-as-possible two-ball rotation task with their dominant hand. During training, three different groups were provided with concurrent visual feedback of the active hand, inactive hand or a mirror image of the active hand with a fourth control group receiving no training. Pre- and post-training performance was measured in both hands. MVF did not increase the extent of training-induced performance changes in the untrained hand following unilateral training above and beyond those observed for other types of feedback. The data are consistent with the notion that cross-limb transfer, when combined with MVF, is mediated by cross-activation with action observation playing a less unique role than previously suggested. Further research is needed to replicate the current and previous studies to determine the clinical relevance and potential benefits of MVF for cases that, due to the severity of impairment, rely on unilateral training programmes of the unaffected limb to drive changes in the contralateral affected limb.     

Relationship between blood lactate and cortical excitability between taekwondo athletes and non-athletes after hand-grip exercise

Objectives: In taekwondo competitions, fatigue has a large influence on performance. Recent studies have reported that the excitability in the primary hand motor cortex, investigated with transcranial magnetic stimulation (TMS), is enhanced at the end of a maximal exercise and that this improvement correlates with blood lactate. The aim of the present study was to investigate the relationship between blood lactate and cortical excitability in taekwondo athletes and non-athletes.

Methods: The excitability of the primary motor cortex was measured before and after fatiguing hand-grip exercise by TMS. Capillary blood lactate was measured at rest (pre-test), at the end (0?min), and at 3 and 10?min after the exercise by using a “Lactate Pro” portable lactate analyzer.

Results: Significant differences in cortical excitability between the two groups were found after the exercise (p?p?Conclusion: The present findings showed changes in the excitability in the athletes group and also in the non-athletes group. However, blood lactate seems to have the greater effect in trained subjects compared to untrained subjects. In fact, it appears that, during extremely intensive exercise in taekwondo athletes, lactate may delay the onset of fatigue not only by maintaining the excitability of muscle, but also by increasing the excitability of the primary motor cortex more than in non-athletes.