ABSTRACT
Introduction: Diaphragmatic surface electromyography is a procedure designed to assess the diaphragm. The physiological values of the electrical activity may have potential use in rehabilitation, sports training, ventilatory support withdrawal in critical care units and follow-up of respiratory disease. Objective: To assess and describe the diaphragmatic function through surface electromyography in a population of individuals during spontaneous and forced breathing. Methods: Observational, exploratory cross-sectional study including subjects with no comorbidities. Diaphragmatic surface EMG was performed measuring the mean quadratic root during tidal volume and vital capacity breathing. The body composition of the participants was also assessed. Results: 28 males and 22 females were included in the study. The mean quadratic root of the tidal volume for two minutes was 13.94 nV for females and 13.31 nV for males. The vital capacity was 23.24 nV for males and 22.4 nV for females. A correlation was identified between the mean quadratic root, weight, and body surface. Conclusions: Mean quadratic root values of tidal volume in two minutes in healthy females and males have been documented. The mean quadratic root values are correlated with the physiological and functional characteristics of the participants.
Introducción: La electromiografía de superficie diafragmática es un procedimiento para la evaluación diafragmática. Los valores fisiológicos de la actividad eléctrica tendrían aplicaciones potenciales en rehabilitación, entrenamiento deportivo, en el retiro ventilatorio en unidades de cuidado crítico y en el seguimiento a patologías respiratorias. Objetivo: Evaluar y describir la función diafragmática a través de electromiografía de superficie diafragmática en una población de sujetos durante la respiración espontánea y la respiración forzada. Métodos: Estudio observacional exploratorio de corte transversal en el que se incluyeron sujetos sin comorbilidades. Se realizó electromiografía de superficie diafragmática midiendo la raíz cuadrática media durante respiraciones de volumen corriente y capacidad vital. Adicionalmente, se valoró la composición corporal de los participantes. Resultados: Se incluyeron 28 hombres y 22 mujeres. La raíz cuadrática media de volumen corriente por dos minutos fue de 13,94 µV para mujeres y 13,31 µV para hombres, mientras que la capacidad vital fue 23,24 µV para hombres y 22,4 µV para mujeres. Se encontró una correlación entre la raíz cuadrática media, el peso y la superficie corporal. Conclusiones: Se han documentado los valores de la raíz cuadrática media de volumen corriente por dos minutos en mujeres y hombres sanos. Los valores de la raíz cuadrática media se correlacionan con características fisiológicas y funcionales de los participantes.
ABSTRACT
Objective To analyze characteristics of motoneurons controlling the extension of a single finger in different individuals, and obtain the similarity and difference of micro-motoneurons characteristics in different individuals. Methods The motoneurons were decomposed by blind source separation algorithm. The two dimensional (2D) features of the neurons were quantified, and the fingers were classified by the features of the neurons decomposed by different individuals. In addition, the proportion of shared motor neurons was used to study characteristics of motoneurons innervating the coordinated movement of different fingers between individuals. Results There were significant differences in spatial distribution of motoneurons between the index finger and the middle finger for different individuals, but the activation area was similar. Using data from different people as training sets and testing sets, the average accuracy of finger classification was 86. 99% , and it was significantly improved to 90. 07% after using transfer component analysis (TCA) calibration. Through analysis on the proportion of shared neurons in different individuals, it was found that the proportion of shared neurons between index finger and other three fingers (middle finger, ring finger and little finger) was relatively low, while that between ring finger and little finger was high. Conclusions The spatial discharge characteristics of motoneurons controlling different fingers in different individuals are similar and have small individual differences. This study reveals the internal neural mechanism of different individuals during finger movement, and provides references for clinical neural mechanism analysis of patients with finger movement disorders and the related engineering applications
ABSTRACT
Objective Aiming at the problems of lacking initiative in upper limb rehabilitation training equipment, single training mode, and low active participation of patients, an upper limb continuous motion estimation algorithm model based on multi-modal information fusion was proposed, so to realize accurate estimation of elbow joint torque. Methods Firstly, the surface electromyography (sEMG) signal and posture signal of participants were collected at four angular velocities, and the time domain characteristics of the signal were extracted. The principal component analysis was adopted to multi-feature fusion. The back propagation neural network (BPNN) was optimized through the additional momentum and the adaptive learning rate method. The particle swarm optimization (PSO) algorithm was used to optimize the neural network and a continuous motion estimation model based on PSO-BPNN was constructed. Finally, the joint torque calculated by the second type of Lagrangian equation was used as the accurate value to train the model. The performance of the model was compared with the traditional BP neural network model. Results The root mean square error (RMSE) of the traditional BP neural network model was 558.9 N·m, and the R2 coefficient was 77.19%, Whereas the RMSE and the R2 coefficient of the optimized model were 113.6 mN·m and 99.12%, respectively.Thereby, the accuracy of torque estimation was improved apparently. Conclusions The method for continuous motion estimation of the elbow joint proposed in this study can estimate the motion intention accurately, and provide a practical scheme for the active control of upper exoskeleton rehabilitation robot.
ABSTRACT
Objective To simultaneously collect and analyze the kinematic and dynamic parameters for two techniques of traditional Chinese cervical manipulation ( TCCM), and quantitatively describe its biomechanical characteristics. Methods A senior practitioner completed the TCCM (positioning and directional rotation pulling, lateral flexion, respectively) on 10 healthy subjects, and the fluorescent marker balls were pasted on the operator to capture manipulation movements. The dynamic parameters and the surface electromyography ( sEMG) signals were collected by pressure-sensitive gloves and wireless sEMG acquisition system. Results The upper arm muscle was the main force muscle during TCCM, and biceps brachii had the highest contribution rate. The range of motion (ROM), speed, pulling force, and time during cervical spine positioning and directional rotation pulling were all greater than those during cervical spine lateral flexion. The integrate electromyography ( iEMG) and root mean square (RMS) for each muscle of the operator during cervical spine positioning and directional rotation pulling were higher than those during cervical spine lateral flexion. Conclusions The overall ROM, three-dimensional (3D) motion angle, load intensity and time during CCTM have the characteristics of high speed, low amplitude and strong force, reflecting the biomechanical characteristics of ‘ cunjin ’ ( one-inch punch ) in traditional Chinese medicine. This study provides references for further standardizing manual teaching and training and improving clinical safety.
ABSTRACT
Objective: To study the protective effect of parachute ankle brace on ankle joint during simulated parachuting landing. Methods: In August 2021, 30 male paratroopers were selected as the test subjects by simple random sampling method. They jumped from the 1.5 m and 2.0 m height platforms respectively with and without parachute ankle brace, and landed on the sandy ground in a semi-squat parachute landing position. The experiment was divided into 1.5 m experimental group and control group and 2.0 m experimental group and control group. Angle sensor and surface electromyograph were used to measure and analyze the coronal tilt range of the ankle joint and the percentage of maximal voluntary contraction (MVE%) of the muscles around the ankle joint, respectively, to evaluate the protective effect of the parachute ankle brace. Results: At the same height, the tilt range of coronal plane of ankle in experimental group was significantly reduced compared with control group, and the difference was statistically significant (P<0.05). Under the same protection state, the tilt range of the coronal plane of the ankle in the 1.5 m group was significantly reduced compared with that in the 2.0 m group, and the difference was statistically significant (P<0.05). The coronal plane inclination range of the ankle in 2 m experimental group was significantly lower than that in 1.5 m control group, and the difference was statistically significant (P<0.05). Compared with 1.5 m control group, MVE% of right tibialis anterior muscle and bilateral lateral gastrocnemius decreased in 1.5 m experimental group, while MVE% of bilateral peroneus longus increased, with statistical significance (P<0.05). Compared with 2.0 m control group, the MVE% of bilateral tibialis anterior muscle and right lateral gastrocnemius decreased in 2.0 m experimental group, while the MVE% of bilateral peroneus longus increased, with statistical significance (P<0.05). The MVE% of bilateral tibialis anterior muscle, bilateral lateral gastrocnemius muscle and right peroneus longus muscle in 1.5 m experimental group decreased compared with 2.0 m experimental group, and the differences were statistically significant (P<0.05). Compared with 2.0 m control group, the MVE% of bilateral tibialis anterior muscle, right lateral gastrocnemius muscle and right peroneus longus muscle in 1.5 m control group decreased, and the differences were statistically significant (P<0.05) . Conclusion: Wearing parachute ankle brace can effectively limit the coronal plane inclination range of ankle joint, improve the stability of ankle joint and reduce the load on the muscles around ankle joint by landing. Reducing the height of the jumping platform can reduce the coronal plane incline range of the ankle and the muscle load around the ankle during landing.
Subject(s)
Humans , Male , Ankle , Ankle Joint/physiology , Lower Extremity/physiology , Muscle, Skeletal/physiology , ElectromyographyABSTRACT
ObjectiveTo compare the short-term effectiveness of the three different manipulations for atlantoaxial joint disorders and their effects on surface electromyography of sternocleidomastoid muscle. MethodsNinty patients with atlantoaxial joint disorders were randomly divided into the tendon relaxing manipulation group， the tendon relaxing plus rehabilitation manipulation group， and the conventional manipulation group， with 30 cases in each group， and each group of patients received the corresponding manipulation treatment for 2 weeks. The changes of visual analogue score （VAS） of occipital neck pain， evaluation scale for cervical vertigo （ESCV）， and averaged electromyography （AEMG） of surface electromyography of bilateral sternocleidomastoid muscles before and after the treatment were observed， and the clinical effectiveness and safety of the patients were compared among groups. ResultsThe VAS scores of patients in each group decreased， and the ESCV scores increased after treatment （P＜0.01）， and the tendon relaxing manipulation group and the tendon relaxing plus rehabilitation manipulation group were significantly better than the conventional manipulation group （P＜0.01）. The AEMG of the bilateral sternocleidomastoid muscles of the three groups increased after treatment （P＜0.01）； when compared among the three groups， the AEMG of the bilateral sternocleidomastoid muscles of the tendon relaxing plus rehabilitation manipulation group was higher than that of the tendon relaxing manipulation group， and the tendon relaxing manipulation group was higher than that of the conventional manipulation group （P＜0.05 or P＜0.01）. The cure and markedly effective rates of the tendon relaxing manipulation group， the tendon relaxing plus rehabilitation manipulation group， and the conventional manipulation group were 56.67%， 86.67%， and 36.67% respectively， showing statistically difference （K=10.21， P＜0.01）. ConclusionThe tendon relaxing manipulation and tendon relaxing plus rehabilitation manipulation can effectively improve the symptoms of vertigo， headache， and neck pain for patients with atlantoaxial joint disorders， and can improve the contraction function of sternocleidomastoid muscle， whose effectiveness are better than that of conventional manipulation.
ABSTRACT
ObjectiveTo observe the lower limb muscle activation strategy of healthy middle-aged and old women during stair ascent and descent with surface electromyography. MethodsFrom August, 2021 to February, 2022, 20 healthy middle-aged and old women were measured the surface electromyography root mean square (RMS) and integrated electromyography (iEMG) of bilateral vastus lateral, rectus femoris, vastus medialis, biceps femoris and semitendinosus during stair ascent and descent, and co-contraction ratio was calculated. ResultsDuring stair ascent, the RMS of bilateral vastus lateral, rectus femoris and vastus medialis was higher at starting stage than at following stage (|t| > 6.650, P < 0.001), while the RMS of biceps femoris and semitendinosus was lower (t > 3.559, P < 0.01); and the co-contraction ratio of hamstrings/quadriceps was lower at starting stage than at following stage (t > 8.185, P < 0.001). During stair descent, the RMS of bilateral vastus lateral, vastus medialis, biceps femoris and semitendinosus was higher at following stage than at starting stage (t > 2.345, P < 0.05), as well as the co-contraction ratio of hamstrings/quadriceps (t > 2.405, P < 0.05). ConclusionThe activities of the muscles around the knees are almost symmetrical during stair ascent and descent for healthy middle-aged and old women. The activation and co-contraction ratio of quadriceps and hamstring are various at starting/following stages.
ABSTRACT
ObjectiveTo explore the effect of core stability training on dynamic balance and surface electromyography (sEMG) after anterior cruciate ligament reconstruction (ACLR), and to analyze the correlation between balance index and sEMG. MethodsFrom March to December, 2022, 32 patients with ACLR in Yantai Affiliated Hospital of Binzhou Medical University were randomly divided into control group (n = 16) and experimental group (n = 16). The control group accepted routine rehabilitation treatment, and the experimental group added core stability training, for six weeks. They were evaluated with American Hospital for Special Surgery Knee Score (HSS) and International Knee Documentation Committee Knee Score (IKDC), and the dynamic balance function and sEMG were measured before and after treatment, and the correlation between dynamic balance index and root mean square (RMS) of sEMG was analyzed. ResultsAfter treatment, the scores of HSS and IKDC increased significantly in both groups (|Z| > 3.526, |t| > 63.544, P < 0.001), and were better in the experimental group than in the control group (Z = -2.392, t = 2.650, P < 0.05); the length of gait line and single support line increased significantly, the medial-lateral displacement displacement decreased (|t| > 2.368, Z = -3.516, P < 0.05), and they were better in the experimental group than in the control group (|t| > 2.497, Z = -3.091, P < 0.05); the RMS of gluteus maximus and gluteus medius increased in the experimental group (t = -5.900, Z = -2.741, P < 0.01), and were better than those in the control group (t = 3.930, Z = -3.260, P < 0.01). After treatment, the RMS of gluteus maximus and gluteus medius in both groups were positively correlated with gait line length and single support line length, and were negatively correlated with medial-lateral displacement (|r| > 0.502, P < 0.01). ConclusionCore stability training could significantly improve knee joint function and dynamic balance, and enhance the activation of gluteus maximus and gluteus medius. Dynamic balance is highly correlated with sEMG.
ABSTRACT
ObjectiveTo explore the neuromuscular control mechanism of training strategies based on mirror neuron system (MNS): action observation (AO), action execution (AE) and action imitation (AO+AE) using functional Near Infrared Spectroscopy (fNIRS) and surface electromyography (sEMG). MethodsFrom July, 2022 to February, 2023, 64 healthy adults were asked to finish four tasks: watching landscape video (control), watching landscape video and acting right wrist and hand extension (AE), watching right wrist and hand extension video (AO), and watching right wrist and hand extension video and acting right wrist and hand extension (AO+AE). A block design was adopted, five times a task in a block, eight cycles, random orders in videos and tasks. The activation of each channel and regions of interest (ROI, namely BA40, BA44, BA45, BA46, BA6 and BA7) in left MNS regions was detected with fNIRS synchronously, as well as the average electromyography (AEMG) of extensor digitorum and extensor carpi radialis with sEMG. ResultsCompared with the control condition, MNS activated in AO, AE and AO+AE conditions, and the intensities mildly increased in turn. Compared with the control condition, 15 channels activated in AO condition, 15 channels activated in AE condition, and all 20 channels activated in AO+AE condition; and the activation intensities of most channels were AO+AE > AE > AO. Four ROI, BA40, BA46, BA6 and BA7, activated in AO condition, all the six ROI activated in AE and AO+AE conditions, and the activation intensities of most ROI were AO+AE > AE > AO. The standardized AEMG of extensor digitorum and extensor carpi radialis were higher in AO+AE condition than in AE condition (|t| > 4.24, P < 0.001). ConclusionMNS has been activated during action observation, execution and imitation, and the ranges and intensities of activation increase in turn. The target muscles activate more during imitation than during execution. Synchronous application of fNIRS and sEMG is feasible in the study of neural mechanism of rehabilitation strategies based on mirror neuron theory.
ABSTRACT
Objective:To observe the clinical effectiveness of manual therapy based on posture decoding for patients with lower crossed syndrome (LCS).Methods:Thirty-six LCS patients were randomly divided into an observation group and a control group, each of 18. The observation group received manual therapy based on posture decoding, while the control group was treated with proprioceptive neuromuscular facilitation (PNF), both in 20min sessions, once a week for 4 weeks. Before the experiment, after one, two and four weeks of treatment and followed-up 4 and 8 weeks later, both groups were evaluated using a visual analogue scale (VAS), the Oswestry Disability Index (ODI) and finger-floor distance (FFD). Anterior pelvic tilt angles (ASIS-PSISs), sacral slopes (SS), lumbar curve index (LCI) and surface EMG flexion-relaxation ratios (FRRs) were also recorded from both groups before and after the treatment.Results:After one and four weeks of the treatment, the average VAS, ODI, and FFD had decreased significantly in both groups, with all significantly lower in the observation group, on average. At the final follow-up, the average VAS and ODI scores of both groups were significantly lower than before the treatment, with those of the observation group significantly lower than the control group′s averages. After 4 weeks of treatment significant differences were observed also in the group′s average ASIS-PSISs, SSs and LCIs compared with before the treatment. And right after the treatment the left and right surface electromyography FRRs of the observation group were significantly higher than those of the control group.Conclusion:Manual therapy based on posture decoding can significantly improve the pelvis forward angle and lumbar motion of LCS patients, relieving back pain and relaxing back muscles.
ABSTRACT
Objective:To observe the impact of core stability training in the sling exercise therapy pattern on the balance of stroke survivors.Methods:Sixty stroke survivors were randomly divided into a control group ( n=30) and an experimental group ( n=30). In addition to routine rehabilitation training, the control group received traditional core stability training, while the experimental group underwent core stability training applying the sling exercise therapy pattern. Before and after 4 weeks of training, the standing balance of both groups was evaluated using the Prokin balance trainer, with the length and area of motion recorded when performing the balance test with the eyes open and closed. Surface electromyography was used to record the average EMG (AEMG) values of the bilateral erector spinae and multifidus muscles during the balance testing. Results:After the 4 weeks of training the length and the area of progression of the center of the pressure were both significantly smaller for both groups than before the training with the eyes both open and closed. The average length and area in the experimental group were significantly less than among the controls. The AEMG values recorded during the balance tests were significantly higher than those before the intervention for both groups, with the multifidus muscle averages on the affected side significantly greater in the experimental group than among the controls when performing the balance test with the eyes closed.Conclusion:Core stability training in the sling exercise therapy pattern is superior to conventional core stability training because it can better improve the balance of stroke survivors.
ABSTRACT
Objective:To observe any effect of dynamic motor instability training on the balance and postural control of stroke survivors.Methods:Forty stroke survivors with poor balance were randomly divided into a control group and an observation group, each of 20. In addition to routine rehabilitation, the observation group was given 20 minutes of dynamic motor instability training, 5 days a week for 8 weeks, while the control group underwent routine rehabilitation for the same length of time. Before and after the intervention, surface electromyogram of the rectus femoris, biceps femoris, and erector spinae were recorded during perturbation. Activation time and the intensity of the anticipatory and complementary postural adjustments (APAs and CPAs) were also observed. Balance and lower limb motor functioning were assessed using the Berg balance scale (BBS), the Fugl-Meyer lower extremity assessment (FMA-LE), and GaitWatch analysis.Results:After the treatment the average activation time of the rectus femoris, biceps femoris in the affected side and those of the biceps femoris [(-84.31±5.74)s] and erector spinae in the intact side in APAs were all significantly shorter in the observation group than in the control group, while the average activation intensity of the rectus femoris and erector spinae was significantly greater. There was no significant difference in the activation intensity of each muscle group in CPAs after the treatment. After the intervention the average BBS score, FMA-LE score, stride length and walking speed of the observation group all were significantly better than the control group′s averages.Conclusions:Supplementing traditional rehabilitation training with dynamic motor instability training can further improve the posture control of stroke survivors and promote recovery of their balance and walking ability.
ABSTRACT
Objective:To observe any effect of electroacupuncture applied to the Jialianquan points in treating post-stroke oropharyngeal dysphagia.Methods:Forty-five stroke survivors with oropharyngeal dysphagia were randomly divided into an electroacupuncture group ( n=15), a neuromuscular electrical stimulation group ( n=15) and a control group ( n=15). All groups received 30 minutes of routine swallowing function training 5 times a week for 3 weeks. The electroacupuncture group was additionally provided with 30 minutes of electroacupuncture applied to the Jialianquan (CV23) points, and the neuromuscular electrical stimulation group instead received 30 minutes of neuromuscular electrical stimulation over the bilateral submental muscles. Videofluoroscopic swallowing studies were performed before and after the 3 weeks of treatment. Standardized swallowing assessment was conducted producing functional oral intake scale ratings, modified barium swallow impairment profiles and the penetration-aspiration scale scores. Surface electromyography was also employed to evaluate submental muscle functioning through measuring the swallowing time, average EMG (AEMG) value and peak amplitude. Results:After the treatment, significant improvement was observed in all of the evaluations with both groups, but the average scores were significantly better in the electroacupuncture and neuromuscular electrical stimulation groups compared with the control group and significantly better in the electroacupuncture group than in the neuromuscular electrical stimulation group.Conclusion:Electroacupuncture at the Jialianquan point can significantly improve the swallowing of stroke survivors with oropharyngeal dysphagia. It is more effective than neuromuscular electric stimulation.
ABSTRACT
Objective To analyze and assess the postoperative motor function in children with spastic cerebral palsy (SCP) by surface electromyography (sEMG) and joint angle. Methods Sixteen children with SCP were involved in this study. The sEMG of rectus femoris, biceps femoris, semitendinosus, tibialis anterior, lateral gastrocnemius and medial gastrocnemius muscles and joint angles of the hip, knee and ankle during straight walking were collected preoperatively and postoperatively. In every gait phase, the mean values of joint angles, root mean square and integrated electromyography of sEMG were calculated, to evaluate muscle strength and muscular tension quantitatively. Results The muscle tension of lower limbs was significantly decreased (P<0.05). The muscle strength of rectus femoris and biceps femoris was decreased in the swing phase. At the midswing and terminal swing phase, the strength of tibialis anterior increased significantly (P<0.05). The flexion angle of hip and knee decreased significantly (P<0.05). The dorsiflexion angle of ankle increased significantly (P<0.05), and the varus angle decreased significantly (P<0.05). Conclusions After operation, the crouching gait and clubfoot were improved positively. Therefore, the motor function of children was improved. Combining sEMG and joint angle can evaluate the muscle function of patients quantitatively, and it also can provide references for clinical diagnosis.
ABSTRACT
Objective To analyze the similarities and differences between four-point hand-knee position and hand-foot kneeling positions in trunk muscle activation and co-contraction, explore the possibility of hand-foot kneeling position as core stabilization exercises, so as to provide suggestions for actual training.Methods Nineteen healthy volunteers randomly performed exercises of four-point hand-knee position (4 motions) and hand-foot kneeling position (3 motions), while surface electromyography (sEMG) signals were collected from bilateral rectus abdominis, external oblique, erector spine, and multifidus muscles. The average sEMG and muscle co-contraction index (CCI) based on the sEMG signals were analyzed and compared.Results Significant differences were found in the sEMG and CCI within and between the two positions. Under four-point hand-knee position with the right hand and left leg lifting, the activation of all muscles was higher than that in the starting position. In four-point hand-knee position with the left leg lifting, the activation of ipsilateral multifidus muscle was significantly higher than that in hand-foot kneeling position. The activation degree of external oblique muscle and rectus abdominis was higher in hand-foot kneeling position with right hand lifting. A total of 28 muscle matching methods were obtained by pair-to-pair matching of 8 muscles. The starting posture in four-point hand-knee position fluctuated the least, indicating that the spine was the most stable, while the index of other exercises fluctuated in a larger range.Conclusions The possibility of hand-foot kneeling position as core stabilization exercises was proved from two aspects, namely, muscle activation and CCI. The hand-foot kneeling position and four-point hand-knee position can be used for strengthening abdominal muscles and back muscles, respectively. The four-point hand-knee position with contralateral upper and lower limbs lift is a more advanced exercise for trunk muscles, but sports injuries should be avoided.
ABSTRACT
Objective: To simulate and evaluate the scraping and grinding work of workers with different spinal anteversion angles, and to explore the effects of different anteversion angles on the erector spinae muscles of scrapers. Methods: In November 2019, 16 male college student volunteers were recruited to simulate workers' scraping and grinding work. The parameters were 25°, 15 times/min, 15°, 30 times/min, 5°, 60 times/min respectively. The surface electromyography (sEMG) was used to collect the electromyographic signals of the erector spinae muscles, and the surface electromyographic characteristics of the erector spinae muscles were evaluated with Borg Scale. Results: There were significant differences between the maximum voluntary contraction percentage (MVE%) of the left and right erector spinae muscles groups in the three groups with different spinal anteversion angles (F(left)=13.41, P(left)<0.001; F(right)=4.74, P(right)=0.005) , and the EMG amplitude was higher at 25°, 15 times/min. At 15°, 30 times/min, MVE% of the left side was significantly higher than that of the right side (t=2.58, P=0.021) . There was significant difference in the mean power frequency (MPF) of the right erector spinae muscle in the three groups (F=9.42, P<0.001) , but there was no significant difference in the MPF of the left erector spinae muscle (F=0.30, P=0.823) . The fitting line showed that the left erector spinae muscle showed a downward trend at 5°, 60 times/min (t=-5.39, P=0.012) . Conclusion: Scrapers are less likely to be fatigued when the posture is 15°, 30 times/min, but they are more likely to be fatigued when working at 5°, 60 times/min.
Subject(s)
Humans , Male , Electromyography , Muscle, Skeletal/physiology , Muscles/physiology , Posture/physiologyABSTRACT
The automatic recognition technology of muscle fatigue has widespread application in the field of kinesiology and rehabilitation medicine. In this paper, we used surface electromyography (sEMG) to study the recognition of leg muscle fatigue during circuit resistance training. The purpose of this study was to solve the problem that the sEMG signals have a lot of noise interference and the recognition accuracy of the existing muscle fatigue recognition model is not high enough. First, we proposed an improved wavelet threshold function denoising algorithm to denoise the sEMG signal. Then, we build a muscle fatigue state recognition model based on long short-term memory (LSTM), and used the Holdout method to evaluate the performance of the model. Finally, the denoising effect of the improved wavelet threshold function denoising method proposed in this paper was compared with the denoising effect of the traditional wavelet threshold denoising method. We compared the performance of the proposed muscle fatigue recognition model with that of particle swarm optimization support vector machine (PSO-SVM) and convolutional neural network (CNN). The results showed that the new wavelet threshold function had better denoising performance than hard and soft threshold functions. The accuracy of LSTM network model in identifying muscle fatigue was 4.89% and 2.47% higher than that of PSO-SVM and CNN, respectively. The sEMG signal denoising method and muscle fatigue recognition model proposed in this paper have important implications for monitoring muscle fatigue during rehabilitation training and exercise.
Subject(s)
Electromyography , Memory, Short-Term , Muscle Fatigue , Neural Networks, Computer , Recognition, PsychologyABSTRACT
ObjectiveTo investigate the changes of surface electromyography (sEMG) of the flexors and extensors of the affected fingers after manual digitorum sensory stimulation (MDSS) in the hemiplegic patients after stroke. MethodsFrom April to August, 2020, 50 stroke patients in Department of Rehabilitation Medicine, the Second Hospital of Anhui Medical University accepted MDSS on the nail beds and the third knuckles of affected fingers, until the fingers extended actively. The tension of affected flexor pollicis brevis, flexor digitorum superficialis and extensor digitorum were assessed with modified Ashworth Scale (MAS) before and immediately after stimulation; while the root mean square (RMS) of sEMG of bilateral flexor pollicis brevis, flexor digitorum superficialis and extensor digitorum were recorded. ResultsThe MAS score of all the muscles decreased after stimulation (|Z| > 2.699, P < 0.01), while the RMS of affected extensor digitorum increased (t = -2.069, P < 0.05). Compared with the unaffected ones, RMS of affected flexor pollicis brevis and extensor digitorum decreased before and after stimulation (t > 2.450, P < 0.05). ConclusionMDSS may immediately relieve the spasm of flexors of hemiplegic fingers after stroke, which associates with the promoting muscle strength of the extensors.
ABSTRACT
@#Objective To compare the effects of Flexi-bar training in different exercise patterns on trunk stability muscles.Methods From June, 2020 to January, 2021, 21 healthy men in Beijing Bo'ai Hospital finished Flexi-bar exercise in seven patterns in random order, namely no vibration, two hands-front vibration, dominant hand-front vibration, non dominant hand-front vibration, two hands-up vibration, two hands-down vibration and two hands-back vibration. The average voltage of electromyography of upper trapezius, middle trapezius, lower trapezius, latissimus dorsi and lumbar multifidus were recorded with surface electromyography during seven kinds of Flexi-bar exercise.Results The average voltage of lumbar multifidus was the most as two hands-front vibration (F=42.362, P<0.001); however, it was the most for upper trapezius and lower trapezius as two hands-up vibration (F > 10.935, P<0.001), it was the most for latissimus dorsi as two hands-back vibration (F=35.243, P<0.001), and it was the most for ipsilateral middle trapezius as non dominant hand-front vibration (F=40.400, P<0.001).Conclusion Flexi-bar training can effectively activate the contraction of trunk stability muscles, and it can be optimized in targeted patterns.
ABSTRACT
Lower limb ankle exoskeletons have been used to improve walking efficiency and assist the elderly and patients with motor dysfunction in daily activities or rehabilitation training, while the assistance patterns may influence the wearer's lower limb muscle activities and coordination patterns. In this paper, we aim to evaluate the effects of different ankle exoskeleton assistance patterns on wearer's lower limb muscle activities and coordination patterns. A tethered ankle exoskeleton with nine assistance patterns that combined with differenet actuation timing values and torque magnitude levels was used to assist human walking. Lower limb muscle surface electromyography signals were collected from 7 participants walking on a treadmill at a speed of 1.25 m/s. Results showed that the soleus muscle activities were significantly reduced during assisted walking. In one assistance pattern with peak time in 49% of stride and peak torque at 0.7 N·m/kg, the soleus muscle activity was decreased by (38.5 ± 10.8)%. Compared with actuation timing, the assistance torque magnitude had a more significant influence on soleus muscle activity. In all assistance patterns, the eight lower limb muscle activities could be decomposed to five basic muscle synergies. The muscle synergies changed little under assistance with appropriate actuation timing and torque magnitude. Besides, co-contraction indexs of soleus and tibialis anterior, rectus femoris and semitendinosus under exoskeleton assistance were higher than normal walking. Our results are expected to help to understand how healthy wearers adjust their neuromuscular control mechanisms to adapt to different exoskeleton assistance patterns, and provide reference to select appropriate assistance to improve walking efficiency.