Effect of transcranial direct current stimulation on human single-leg landing stability / 中国组织工程研究

BACKGROUND:Transcranial direct current stimulation(tDCS),as a non-invasive brain stimulation technique,can enhance human muscle strength or improve single-leg landing stability instantly,but no relevant research has demonstrated this yet. OBJECTIVE:To investigate the effect of tDCS on the stability of single-leg landings in human subjects. METHODS:Male undergraduate students from Wuhan Sports University were recruited as study participants.They were divided into two groups,A(n=6)and B(n=5),using a random number table.Group A underwent a sham stimulation session followed by a 3-day washout period,after which they received tDCS.Conversely,Group B received tDCS initially,followed by a 3-day washout period,and subsequently underwent the sham stimulation session.Following the respective stimulation sessions,an immediate single-leg landing test was administered to assess and collect biomechanical parameters.Data resulting from the tDCS intervention were aggregated and analyzed as the experimental group dataset,whereas data stemming from the sham stimulation were consolidated as the control group dataset. RESULTS AND CONCLUSION:Regarding core stability,the tDCS intervention showed a significant interaction with landing height on the maximal trunk flexion angle(P＜0.05).A paired comparison of the data showed a significant decrease in the maximum trunk flexion angle following true stimulation compared to sham stimulation at a 30-cm landing height.Additionally,the tDCS intervention had a significant main effect on the maximum trunk lateral bending angle and the mean trunk lateral bending angular velocity(P＜0.05).Following true stimulation,there was a significant decrease in the maximum trunk lateral bending angle and the mean trunk lateral bending angular velocity compared to sham stimulation.In terms of lower limb joint stability,the tDCS intervention had a significant main effect on the maximum dynamic ankle valgus angle(P＜0.05).This resulted in a significant decrease in the angle following true stimulation compared to sham stimulation.In addition,the tDCS intervention had a significant main effect on the peak muscle activation of the lateral head of the gastrocnemius lateralis(P＜0.05).This showed a significant increase after true stimulation compared to sham stimulation.An interaction between the tDCS intervention and landing height was observed for the peak muscle activation of the tibialis anterior(P＜0.05).Paired comparison analyses revealed a significant increase in muscle activation after true stimulation specifically at a 60-cm landing height.Regarding center of pressure stability,there were no significant interactions or main effects of the tDCS intervention on the mean lateral displacement,mean lateral displacement velocity,mean anterior-posterior displacement,or mean anterior-posterior displacement velocity at the center of pressure(P＞0.05).Furthermore,the tDCS intervention had no significant main effects on any of the center of pressure indicators(P＞0.05).In conclusion,tDCS can immediately improve core stability and lower limb joint stability during single-leg landing,making it an effective warm-up technique for improving single-leg landing stability and reducing the risk of lower limb injuries.

Relationship between muscle activation characterization and fall risk in older adults during walking up and down stairs / 中国组织工程研究

BACKGROUND:During stair walking,different muscles work in concert and compensate for each other,and it is unclear whether weakened muscle strength actually affects stair fall risk in older adults.Real-time electromyographic signals from older adults during stair walking are used to reflect high fall risk in older adults during stair walking,which may further improve the accuracy of prediction methods. OBJECTIVE:To investigate the effects of aging on lower limb muscle activation in older adults during stair walking and to analyze the relationship between their muscle activation characteristics and stair fall risk. METHODS:Subjects were divided by age into an older group(n=19)and a younger group(n=18)group and were asked to walk on a 10-step staircase at a natural speed,incorporating surface electromyography acquisition technology,to capture surface electromyography signals during stair walking and calculate the root mean square(RMS)to analyze differences in muscle activation levels.Logistic regression analysis was utilized to establish a predictive model for stair fall risk in older adults by incorporating the lateral femoral and gastrocnemius muscle RMS.The discrimination of the model was evaluated by the receiver operating characteristic curve and area under the curve,and the fit of the model was evaluated using the Hosmer-Lemeshow test RESULTS AND CONCLUSION:Activation of the rectus femoris(Z=-3.464,P=0.001;t=3.379,P=0.002)and lateral gastrocnemius muscle(Z=-2.978,P=0.003;Z=-3.555,P<0.001)was higher in older adults than in younger adults when walking up and down stairs.Activation of the anterior tibialis(Z=-2.350,P=0.019)and medial(Z=2.321,P=0.020)and lateral(t=3.158,P=0.004)gastrocnemius muscles was higher in older adults when ascending stairs than descending stairs.Older adults at risk for falls had less activation of the lateral femoral muscle(Z=-2.613,P=0.009),medial gastrocnemius muscle(Z=-2.286,P=0.022)when walking upstairs,and lateral femoral muscle(Z=-2.368,P=0.018)when walking downstairs than did older adults not at risk for falls.The predictive ability,goodness of fit,and discrimination of the stair fall prediction model for older adults based on surface electromyography were good(P-value of 0.010 for the Omnibus test of the model coefficients,P-value of 0.214 for the Hosmer-Lemeshow test,and the area of the curve of the upper staircase lateral femoral muscle=0.856,P=0.009).(5)The model was modeled with a cut-off value of 38.64 for the upper staircase lateral femoral muscle RMS value and there was a 0.952-fold increase in the risk of staircase falls for each unit decrease in the upper staircase lateral femoral muscle RMS in older adults.

Effects of Repetitive Transcranial Direct Current Stimulation on Anti-Fatigue Capacity in High-Intensity Jumping Exercise / 中国运动医学杂志

Objective To explore the effect of repetitive transcranial direct current stimulation(tDCS)on anti-fatigue capacity,power output,and muscle activation during continuous vertical jumps of aver-age undergraduates.Methods Thirty healthy male college students were randomly assigned to an anodal tDCS(a-tDCS)group and a sham tDCS(sham-tDCS)group,receiving a total of 10 repeated anodal tDCS and sham tDCS for 5 consecutive days on the primary motor cortex respectively.Before and right after the intervention,as well as one month after the intervention,all students underwent the continuous vertical jump test.The two-factor repeated measure ANOVA(stimulation condition×time)was employed to evaluate alterations in fatigue index,total jump height,lower limb stiffness and mus-cle activation characteristics.Results The fatigue index of the a-tDCS group was significantly lower than the sham-tDCS group(P<0.05).After a-tDCS,the total jump height was significantly higher than before(P<0.05).In the sham-tDCS group,the touchdown time during continuous vertical jumps in-creased more significantly right and a month after the intervention(P<0.05 for both).Moreover,lower limb stiffness of the a-tDCS group at the last moment of the continuous vertical jumps was significant-ly higher than the sham-tDCS group(P<0.05).After a-tDCS,the activation of the rectus femoris mus-cle increased significantly in the eccentric phase of the end of the test(P<0.05).However,no signifi-cant differences were found in the mean power and post-test rating of perceived exertion after the stim-ulation.Conclusion Ten sessions of tDCS conducted over five consecutive days demonstrates an en-hancement in neuromuscular activation during high-intensity jumping exercise.This observed augmenta-tion contributes to attenuating the decline in exercise capacity associated with fatigue.

Functional Anatomy of the Hamstring Muscle and Its Correlation with the Various Yogic Postures: A Narrative Review

Yoga is believed to be a safe practice; nonetheless, as the number of yoga practitioners has grown, so has the incidence of yoga-related injuries. Overall, lower extremity injuries comprised 64% of total injuries; specifically, the hip, hamstring, knee, ankle, feet and toe. Although a few research studies have quantified the hamstring muscle activities in various yoga asanas, evidence correlating it to functional anatomy is scarce. Therefore, the objective of this narrative review is to examine the literature and analyse hamstrings activity and its relationship to yogic postures, as well as yoga-related injuries, to establish which poses provide the most risk of damage, and to suggest injury-prevention techniques. The following electronic databases were used to conduct the literature search: Cochrane Library, PubMed, Google Scholar, EMBASE, and Web of Science. hamstring muscle injuries OR yoga and rehabilitation OR intervention AND electromyography was among the search phrases utilized. Such information is important for yoga teachers, yoga therapists to help selecting yoga posture for hamstring muscle imbalance condition and avoiding posture to prevent hamstring muscle injury.

Comparative Analysis on Two Different Algorithms for Estimating Muscle Forces / 医用生物力学

Objective To explore the differences between the result of static optimization (SO) and computational muscle control (CMC) algorithms for estimating muscle forces, so as to provide references for researchers to choose the appropriate algorithm and make horizontal comparison of the results from different studies. Methods Targeting at a single gait cycle running at four different speeds, SO and CMC algorithms were used to calculate forces and activations of the major muscles in lower limbs, and the results were compared and analyzed. Results Among the 10 major muscles participating in running, except for anterior tibial and rectus femoris, muscle forces and muscle activations solved by the two algorithms had similar curves with correlation coefficients more than 0.91, and the peak value of muscle forces solved by SO was higher and the positions of peak muscle activation had a 10 ms delay. Conclusions In movement analysis, if the research focuses on the timing of muscle forces and the contribution ratios among different muscles, there is not too big difference and SO algorithm is recommended for its simplicity and efficiency. For horizontal comparison of muscle forces and muscle activations estimated by SO and CMC algorithms in different studies, the differences between the two algorithms should be considered.

Neuromuscular compartmentalization of the vastus medialis muscle: comparison of the activity of the vastus medialis obliquus and the vastus medialis longus by high density electromyography / Compartimentación neuromuscular del músculo vasto medial: comparación de la actividad del vasto medial oblicuo y del vasto medial largo mediante electromiografía de alta densidad

SUMMARY: Anatomical studies describe the vastus medialis (VM) as being subdivided into two morphologically distinct components, the vastus medialis obliquus (VMO) and the vastus medialis longus (VML). However, there are discrepancies regarding the functional differentiation of these components. The aim of this study was to compare the levels of activation of the VMO and the VML by high density surface electromyography. Twelve healthy young women (age: 21.4 ± 2.0 years; weight: 58.1 ± 7.5 kg; height: 1.6 ± 0.1 m), performed an open kinetic chain knee exercise during which the EMG activity of the VMO and the VML was recorded with two- dimensional matrices of 32 surface electrodes. The exercises were performed with three levels of resistance (5, 10 and 15 % of the body weight (BW)), considering three phases: concentric, isometric and excentric. In the isometric phase the VMO had greater activation than the VML with the three levels of resistance (p<0.05). In the excentric phase, the VMO also showed greater activation than the VML with the 10 and 15 % BW resistance levels, while in the concentric phase, the VMO showed greater activity than the VML with only the 15 % BW resistance. The results indicated significant differences in the activation level of the two components of the VM. This bears importance in the development of exercises intended to achieve a greater or more selective activation of the VMO. In the sample subjected to evaluation, the EMG recordings describe a greater activation of the VMO in comparison to the VML, which is more important in the isometric and excentric phases of the flexion/extension of the knee in an open kinetic chain. These findings suggest a functional compartmentalization of the VM.

RESUMEN: Los estudios anatómicos describen que el músculo vasto medial (VM) se subdivide en dos componentes morfológicamente distintos, el vasto medial obliquus (VMO) y el vasto medial largo (VML). Sin embargo, existen discrepancias con respecto a la diferenciación funcional de estos componentes. El objetivo de este estudio fue comparar los niveles de activación del VMO y el VML mediante electromiografía de superficie de alta densidad. Doce mujeres jóvenes sanas (edad: 21,4 ± 2,0 años; peso: 58,1 ± 7,5 kg; altura: 1,6 ± 0,1 m), realizaron un ejercicio de rodilla de cadena cinética abierta durante el cual se registró la actividad EMG de la VMO y la VML con dos matrices dimensionales de 32 electrodos de superficie. Los ejercicios se realizaron con tres niveles de resistencia (5, 10 y 15% del peso corporal (PC)), considerando tres fases: concéntrica, isométrica y excéntrica. En la fase isométrica el VMO tuvo mayor activación que el VML con los tres niveles de resistencia (p <0,05). En la fase excéntrica, el VMO también mostró mayor activación que el VML con los niveles de resistencia de 10 y 15% BW, mientras que en la fase concéntrica, el VMO mostró mayor actividad que el VML con solo el 15 % de resistencia al BW. Los resultados indicaron diferencias significativas en el nivel de activación de los dos componentes de la VM. Esto tiene importancia en el desarrollo de ejercicios destinados a lograr una activación mayor o más selectiva del VMO. En la muestra sometida a evaluación, los registros EMG describen una mayor activación del VMO en comparación con el VML, que es más importante en las fases isométrica y excéntrica de la flexión / extensión de la rodilla en cadena cinética abierta. Estos hallazgos sugieren una compartimentación funcional de la VM.

Effects of Gender and Maneuvers on ACL Injury Risk Factors for Volleyball Players / 医用生物力学

Objective To study the effect of gender and maneuvers on anterior cruciate ligament (ACL) injury risk factors for volleyball players. Methods Sports biomechanics data of volleyball players during stop-jump, drop landing and sidestep cutting were collected. The ACL injury rate and biomechanical parameters of simulated injured jumps were obtained with Monte Carlo simulation. The influence of gender and maneuvers on ACL injury risk factors was validated by 2×3 mixed designed two-way ANOVA. Results Sidestep cutting was the highest risk maneuver of ACL injury for both genders (P＜0.001). Compared with male players, female players had a greater risk of ACL injury during sidestep cutting and stop-jump (P＜0.001), while male players were more prone to have ACL injury than female players during drop landing (P＜0.001). The risk factors of ACL injury obtained by simulation were significantly influenced by gender and maneuvers (P＜0.001). Conclusions Male players were more likely to increase ACL load due to smaller knee flexion, forward leg tilt and heel landing than female players during sidestep cutting, while female players owned larger ground reaction force (GRF) and knee extension moment. Smaller knee flexion angle during stop jump was the major risk factor for both genders, however more characteristics contributed to the males. Female players with large GRF, knee valgus and extension moment, and heel-landing were likely to have ACL injury, while the small knee flexion angle was the key risk factor for male players. The results can provide evidences for evaluation of volleyball players’ ACL injury risk, individualized injury prevention protocols, and clinical treatment and rehabilitation directions.

Biomechanical and Dynamic Characteristics of Human Body during Exercise on Elliptical Cross Trainer / 医用生物力学

Objective To analyzes the biomechanical and dynamic characteristics of human body during exercise on elliptical cross trainer. Methods An elliptical cross trainer model and a human skeletal muscle model were built by three-dimensional (3D) modeling software and AnyBody software, respectively, which were then coupled and simulated. Results During exercise on elliptical cross trainer, the lumbar spine L5 was subjected to the maximum force 1023 kN, and the maximum activation of external oblique and internal oblique muscles were 80% and 40%, respectively. The maximum muscle activation in lower limb muscle groups did not exceed 40%, and the maximum plantar ground reaction force was 600 N. Conclusions The use of elliptical cross trainer can alleviate the pain of patients with chronic low back pain, and help to improve the trunk control and balance function of patients with stroke and hemiplegia. Compared with running exercise, exercise on elliptical cross trainer can protect the human knee joint.

Gait Simulation and Analysis of Lower Limb Musculoskeletal Model before and after Total Knee Arthroplasty / 医用生物力学

Objective To compare and analyze the lower limb muscle activity and knee joint force during the stance periods of gait cycle in patients with osteoarthritis before and after total knee arthroplasty (TKA). Methods Based on the OpenSim platform, lower extremity musculoskeletal models of one healthy subject and three patients with osteoarthritis before and after TKA were established. A three-dimensional （3D） motion capture system and a force platform were used to collect the lower limb kinematic data and the ground reaction force during walking, which were used as input parameters to simulate the lower limb muscle activation and knee joint forces. Results The results from the musculoskeletal model were consistent with the results by inverse dynamics based on the 3D motion capture system. The patient's rectus femoris was activated in the loading response and mid stance phases, which was different from that of healthy subject. The activation timing and amplitude of the quadriceps muscle in 3 patients were significantly different before and after TKA. The peak joint forces of 3 patients before TKA were 2.95, 3.15 and 3.43 times of body weight (BW) with the constant load of more than 2 times of BW during stand phase. The peak joint force after TKA were 2.09, 2.48 and 3.96 times of BW respectively. The joint force was not improved and the knee function did not reach the normal level six months after TKA. Conclusions The results of the established musculoskeletal model have certain reliability, and this model can provide a biomechanical auxiliary method for TKA surgery in the future.

Muscle activation pattern of gluteus medius, tibialis anterior and peroneus longus during drop landing on different surfaces: A cross-sectional study

BACKGROUND@#Gluteus medius (GMeds), peroneus longus (PL), and tibialis anterior (TA) help in maintaining frontal stability of the lower extremity, particularly, the ankle. Muscle activation must be sufficient to prevent the occurrence of an ankle sprain. The purpose of this study is to compare the muscle activation of the GMeds, TA, and PL during drop landing on stable and unstable surfaces of physically active individuals.@*METHODS@#Surface EMG (sEMG) was used to determine the muscle activation pattern of the GMeds, TA, and PL of fifteen (15) recreational athletes during drop landing. The mean percentage of maximum voluntary isometric contraction (%MVIC) was calculated for comparison. Wilcoxon signed-rank test was used to compare means.@*RESULTS@#There were no statistically significant differences in the muscle activity of GMeds (p=0.69), TA (p=0.26), and PL (p=0.23) on stable and unstable surfaces. However, a small effect size showed that GMeds (d=0.30) has higher activation in the unstable surface while TA (d=0.28) and PL (d=0.17) have lower activation on unstable surface.@*CONCLUSION@#Landing surface does not significantly alter muscle activity of GMeds, TA, and PL. However, the magnitude of the difference in the mean %MVIC between groups shows the compensatory mechanism of the body when subjected to different surface conditions. This can be used when creating injury prevention programs of the lower extremity.

Efeito da estimulação elétrica periférica e cerebral na força isométrica máxima dos extensores do joelho: ensaio clínico aleatorizado / Effects of peripheral and cerebral electrical stimulation on maximal isometric strength of knee extensors: a randomized clinical trial

INTRODUÇÃO: Recentes evidências têm demonstrado resultados bastante promissores para o uso de estratégias não invasivas de neuromodulação na melhora de habilidades físicas ou esportivas. A estimulação elétrica periférica (EEP) e a estimulação transcraniana por corrente contínua (ETCC) são técnicas não invasivas e não farmacológicas bastante utilizadas para modular a excitabilidade neuronal de áreas cortico-motoras e estimular a recuperação funcional. No entanto, poucos estudos têm investigado o efeito dessas técnicas na melhora do desempenho muscular. OBJETIVO: Investigar o efeito da estimulação elétrica periférica sensorial (EEPs) seguida de estimulação elétrica periférica motora (EEPm) ou estimulação transcraniana por corrente contínua (ETCC) na força isométrica máxima dos extensores do joelho em indivíduos saudáveis. MÉTODO: 20 universitários saudáveis foram distribuídos aleatoriamente em dois blocos distintos de 10 participantes cada: Bloco n°1 EEPs real + EEPm real ou EEPs simulada + EEPm real e bloco n°2 EEPs real + ETCC real ou EEPs simulada + ETCC real em uma única sessão. A contração voluntária isométrica máxima (CVIM) dos extensores do joelho foi avaliada por meio da dinamometria manual antes, durante e 10 min pós-estimulação. RESULTADOS: A CVIM dos extensores do joelho aumentou significativamente 10 minutos pós-ETCC isolada (diferença média = 0,23 N/Kg; IC 95% = 0,01 a 0,44 N/Kg; p = 0,04). A ETCC isolada também apresentou maior proporção cumulativa de respondedores seguido de EEPs+ETCC. CONCLUSÃO: A estimulação transcraniana por corrente contínua induz a aumentos significativos na CVIM em indivíduos saudáveis. No entanto, a aplicação prévia de estimulação elétrica periférica sensorial não impulsiona os efeitos da estimulação elétrica periférica motora ou cerebral na CVIM.

INTRODUCTION: Recent evidence has shown very promising results for the use of noninvasive neuromodulation strategies in improving physical strength or sports skills. Peripheral electrical stimulation (PES) and transcranial direct current stimulation (tDCS) are non-invasive and non-pharmacological techniques widely used to modulate neuronal excitability of corticomotor areas and to induce functional improvements. However, few studies have investigated the effect of these techniques on improving muscle performance. OBJECTIVE: To investigate the effect of sensory peripheral electrical stimulation (PESs) followed by motor peripheral electrical stimulation (PESm) or transcranial direct current stimulation (tDCS) on the maximal isometric force production of the knee extensors in healthy individuals. METHODS: Twenty healthy university students were randomly assigned to two distinct blocks with 10 participants in each block: 1) block n°1 PESs + PESm or sham PESs + PESm, 2) block n°2 PESs + tDCS or sham PESs + tDCS (each in a single session). The maximum voluntary isometric contraction (MVIC) of the knee extensors was evaluated by manual dynamometry pre-, during and 10 min post-stimulation. RESULTS: MVIC of the knee extensors was significantly increased 10 min post-tDCS alone (mean difference = 0.23 N/kg, 95% CI = 0.01 to 0.44 N/kg, p = 0.04). Isolated tDCS also had a higher cumulative proportion of responders, followed by PESs + tDCS. CONCLUSIONS: Transcranial direct current stimulation induces a significant increase in MVIC in healthy subjects. However, prior application of peripheral electrical stimulation does not compound the effects of peripheral electrical motor or cerebral stimulation.

The timing of muscle activation in walking after a stroke / 中华物理医学与康复杂志

Objective To observe among stroke survivors the timing of muscle activation at the stance phase during walking using the surface electromyography ( sEMG) combined with 3D gait analysis. Methods Twenty stroke survivors assessed as at Brunnstrom stages Ⅲ, Ⅳ and Ⅴ were assigned to groups designated Ⅲ, Ⅳ and V. sEMG and 3D gait analysis were used to assess the activation timing of the bilateral rectus femoris ( RF) and biceps femoris ( BF) , the tibialis anterior ( TA) and the gastrocnemius medialis ( GM) . The activation timing and the dura-tion of activation of the muscles were compared among the 3 groups, as well as with those of healthy muscles. Results The onset time of the RF on the affected side was significantly later than on the healthy side, while that of the GM was significant earlier. The durations of BF and GM activation on the affected side were significantly shorter than on the unaffected side in group III. The onset times of the TA and GM on the affected side were significantly ear-lier than on the healthy side in group IV, as was the onset time of the TA of the affected side in group V. The average RF and BF onset times on the affected side in group Ⅳ were significantly earlier than in group Ⅲ. The onset time of the TA on the unaffected side and the average BF onset time on the affected side in group Ⅴ were significantly later than in group IV. The onset time of the RF and TA on the unaffected side in group Ⅳ and the onset time of the GM on the affected side were significantly later than in group III, while the onset time of the BF and TA on the affected side was significantly earlier. The average duration of BF activation on the unaffected side in group Ⅳ was significant-ly shorter than that of group Ⅲ. The average duration of TA activation on the unaffected side in group Ⅴ was signifi-cantly shorter than that of group IV. The duration of RF activation on the affected side in group Ⅴ was significantly shorter than that in group Ⅲ, and the same was true of the RF, BF, TA and GM activation times on the healthy side. Conclusions There are significant differences in the onset and duration of muscle activation when stroke survivors at different stages of recovery walk. Some muscles are activated too early and others are over-activated. These abnormali-ties gradually disappear with the recovery of motor function.

Effects of Squatting with Different Foot Positions on Muscle Activations in Subjects with Genu Varum

PURPOSE: This study examined the effects of squatting with different foot positions on the muscle activation of the vastus medialis oblique (VMO) and vastus lateralis (VL) muscles in subjects with genu varum. METHODS: Thirty four subjects participated in this study. Surface electromyography was used to measure the muscle activation of the VMO and VL muscles at the knee angles (15°, 60°) at three foot positions (internal rotation, neutral position, external rotation) during squatting. RESULTS: Muscle activation differences at different knee angles and foot positions differed significantly between the VMO and VL muscles in both the varus and normal groups. In addition, there was a significant difference according to the knee angles with the foot in external rotation in the VMO and VL ratio. In the varus group, however, the VMO and VL ratio were significantly different only with the feet in internal rotation. In the muscle activation changes of the knee angle differences in the foot position, there was no significant difference in the varus group, but both the VMO and VL muscles were significant different in the normal group. CONCLUSION: In both groups, regardless of the foot position, muscle activation of the VMO and VL muscles increased with increasing knee flexion angle. In the normal group, when squatting with the feet in external rotation, the VMO and VL muscles activations increased with increasing knee angle. In the varus group, however, the foot position did not affect the VMO or VL muscle activation. This study shows that subjects with genu varum and normal subjects have different VMO and VL muscle activation patterns during squat exercises.

Choice of Muscles for Extracting Consistent Motor Modules: The Effect of Trial-to-Trial Electromyography Repeatability / 医用生物力学

Objective To identify the effect of the repeatability of muscle activations on extraction of consistent motor modules across trials. Methods The activities of sixteen muscles in twelve subjects who consistently walked at a self-selected speed were recorded. The intraclass correlation coefficient (ICC) was used to identify inter-stride repeatability of muscle activities and motor modules. Based on the repeatability of muscle activation, three types of muscle sets were organized. Results The reliable set containing the muscles showed high ICC (>0.4), but the whole-body and mixed sets containing the muscles showed poor ICC (＜0.4). When motor modules were extracted from each set, the reliable set showed the highest repeatability of motor module extraction, but the whole-body and mixed sets presented significantly lower repeatability. Conclusions Greater repeatability of muscle activations result ed in consistent motor modules. Extraction of consistent motor modules was a critical issue, especially in real-time motion recognition based on muscle patterns.

Choice of Muscles for Extracting Consistent Motor Modules: The Effect of Trial-to-Trial Electromyography Repeatability / 医用生物力学

Objective To identify the effect of the repeatability of muscle activations on extraction of consistent motor modules across trials. Methods The activities of sixteen muscles in twelve subjects who consistently walked at a self-selected speed were recorded. The intraclass correlation coefficient (ICC) was used to identify inter-stride repeatability of muscle activities and motor modules. Based on the repeatability of muscle activation, three types of muscle sets were organized. Results The reliable set containing the muscles showed high ICC (>0.4), but the whole-body and mixed sets containing the muscles showed poor ICC (＜0.4). When motor modules were extracted from each set, the reliable set showed the highest repeatability of motor module extraction, but the whole-body and mixed sets presented significantly lower repeatability. Conclusions Greater repeatability of muscle activations result ed in consistent motor modules. Extraction of consistent motor modules was a critical issue, especially in real-time motion recognition based on muscle patterns.

Effects of Flexible Pole Training Combined with Lumbar Stabilization on Trunk Muscles Activation in Healthy Adults

OBJECTIVE: This study aimed to determine the efficacy of flexible pole training combined with lumbar stabilization in improving trunk muscle activities and to investigate the difference according to posture in young adults. METHODS: Twenty-five participants were enrolled in this study. The subjects were randomly allocated into either the flexible pole group or the rigid pole group. Participants performed lumbar stabilization exercises on quadruped and curl-up, with the flexible pole or rigid pole. Electromyography was used to assess the percent maximal voluntary isometric contracion (%MVIC) of the rectus abdominis (RA), external oblique (EO), internal oblique (IO), and erector spine (ES) muscles. All participants completed one 30-minute session per day, 3 days per week, for 6 weeks. The evaluation was performed before and 6 weeks after the training, and follow-up. The data were analyzed using independent t-test and two-way repeated measure analysis of variance to determine the statistical significance. RESULTS: The flexible pole in curl-up showed significant differences in EO and IO muscle activities compared with the rigid pole. The flexible pole in quadruped showed significant differences in IO and ES muscle activities compared with the rigid pole. The RA, EO, IO, and ES muscle activities of both groups were significantly higher after 6 weeks training. CONCLUSION: The flexible pole in curl-up and quadruped showed an improvement in trunk muscle activation. The flexible pole combined with lumbar stabilization will be useful as an exercise tool to improve activity of trunk muscles.

Neuromuscular Activation in Patients with Chronic Ankle Instability (review) / 中国康复理论与实践

This article introduced the neuromuscular activation characteristics of patients with chronic ankle instability during dif-ferent movement patterns, and explained the reasons of deficits of neuromuscular control in lower extremity muscle ac-tivity, kinetics, and kinematics, which aimed at further clarifying the mechanism of chronic ankle instability, and provid-ing theoretical basis for its rehabilitation training.

Electromyographic evaluation of the lower limbs of patients with Down syndrome in hippotherapy / Avaliação eletromiográfica dos membros inferiores de pacientes com síndrome de Down na equoterapia

Hippotherapy is a therapeutic method that uses the horse's movement to achieve functional results in practitioners with Down syndrome (DS), who present motor and neurophysiological changes that affect the musculoskeletal system. Evaluating the motor behavior related to the control and the improvement of muscle activation in practitioners with Down syndrome subjected to hippotherapy. 10 practitioners were divided into two groups: Down Group (DG) ­ practitioners with DS, and Healthy Group (HG) ­ practitioners with no physical impairment. The muscles gluteus medius, tensor fasciae latae, rectus femoris, vastus medialis, vastus lateralis, biceps femoris, tibialis anterior and gastrocnemius were evaluated by electromyography using gross RMS values, which correspond to muscle activation; the evaluations were performed on the 1st and 10th hippotherapy sessions (frequency: once a week), and after 2 months interval without treatment, they were performed on the 1st and 10th hippotherapy sessions (frequency: twice a week). It was noted that activation of the studied muscles increased with the passing of sessions, regardless the weekly frequency of attendance; however, the period without treatment resulted in reduction of this effect. Practitioners with DS presented satisfactory changes in muscle activation pattern, in learning and in motor behavior during hippotherapy sessions.

Equoterapia é um método terapêutico que utiliza o movimento do cavalo para alcançar resultados funcionais, realizada em praticantes com síndrome de Down (SD), que apresentam alterações neurofisiológicas e motoras que afetam o sistema musculoesquelético. Avaliar o comportamento motor relacionado ao controle e melhora a ativação muscular em praticantes com SD submetidos ao tratamento equoterapêutico. Participaram dez praticantes divididos em dois grupos: grupo Down (GD) - praticantes com SD, e grupo Saudável (GS) - praticantes sem comprometimento físico. Os músculos glúteo médio, tensor da fáscia lata, reto femoral, vasto medial, vasto lateral, bíceps femoral, tibial anterior e gastrocnêmio foram avaliados por meio da eletromiografia, utilizando o valor de RMS bruto que corresponde à ativação muscular, e as avaliações foram realizadas na primeira e décima sessões de equoterapia (frequência: 01 vez por semana); e após intervalo de dois meses sem tratamento, foi realizada na primeira e décima sessões de equoterapia (frequência: 02 vezes por semana). Observou-se que a ativação muscular dos músculos estudados aumentou com o passar das sessões, independente da frequência semanal de atendimento; mas o período sem tratamento resultou em redução deste efeito. Os praticantes com SD apresentaram mudanças satisfatórias no padrão de ativação muscular, na aprendizagem e no comportamento motor no decorrer das sessões de equoterapia.

The Effect of Plank Exercises with Hip Abduction Using Sling on Trunk Muscle Activation in Healthy Adults

PURPOSE: The purpose of this study is to investigate the effects of healthy persons performing a plank exercise with hip abduction and use of sling on trunk muscle activity. METHODS: Twenty-three subjects participated in this study. Muscle activities of the multifidus, rectus abdominis, external oblique and internal oblique were assessed with electromyography (EMG) while the subjects performed 6 various types of plank exercises in random order. RESULTS: There was a significant difference in multifidus and internal oblique on the supported side and the multifidus, external oblique, and internal oblique on the elevated side (p<0.05), and differences in plank methods were significantly higher in the multifidus, rectus abdominis, external oblique, internal oblique of the supported side and the rectus abdominis, external oblique and internal oblique on the elevated side (p<0.05). In addition, post-hoc analysis of the various plank methods showed that muscle activity was significantly higher during the general plank exercise compared with the knee-supported-in-sling plank exercises (p<0.05), and was significantly higher with the ankle-supported-in-sling plank exercises compared with the general plank exercise. CONCLUSION: There was greater trunk muscle activity with plank exercises performed with the ankle-supported-in-sling and hip abduction plank exercises compared with the general or knee-supported-in-sling plank exercises. Through this study, various plank exercises have been discovered that can be selected at different intensities for core muscle training purposes based on trunk muscle strength.

Acupuncture combined with ganglioside and mecobalamine injections can relieve the symptoms of idiopathic facial palsy / 中华物理医学与康复杂志

Objective To observe the clinical effect of acupuncture combined with ganglioside and mecobalamine injections on idiopathic facial palsy (IFP).Methods A total of 120 IFP patients were divided into a ganglioside group,a mecobalamine group and a consociation group,each of 40.All were given routine drug and acupuncture treatment,while the ganglioside and mecoblamine groups were additionally provided with the corresponding injections of ganglioside and mecobalamine,respectively.The treatment was administered once daily for a total of 14 days.All the groups were evaluated using the House-Brackmann facial nerve grading system before and after the interventions of 14 days ended.The compound muscle action potential (CMAP) wave amplitude and R1 incubation,the motor nerve conduction velocity (MCV) and the sensory nerve conduction velocity (SCV) of the affected facial nerves were observed and compared before and after the 14 days of treatment.Results The total effectiveness rate of the consociation group (95.0％) was significantly higher than that of the ganglioside (90.0％) or the mecobalamine group (87.5％).After the treatment the CMAP wave amplitude had improved significantly and the R1 latency had shortened significantly in the consociation group compared to the other 2 groups.The average MCV and SCV of the consociation group had also improved significantly compared with the other two groups.Conclusion Acupuncture combined with ganglioside and mecobalamine injections is an effective therapy for idiopathic facial palsy.It can improve the patient's clinical symptoms,shorten the CMAP wave amplitude and R1 latency on the affected side and improve MCV and SCV.