Muscle Activation Characteristics Research Articles

Effect of differentarterial occlusion pressure and intermittent mode on KAATSU-loaded deep-squat exercise on the characteristics of thigh muscle activation

Objective: To investigate the effect of different arterial occlusion pressure and intermittent time on KAATSU-loaded deep-squat exercise on the characteristics of thigh muscle activation, find out the suitable relative value of personal blood pressure limit causing the maximum activation, and to provide some theoretical basis and practical reference for athletes to carry on the KAATSU Training scientifically. Methods: Ten elite male players were recruited, four kinds of external pressure condition with 0% arterial occlusion pressure (AOP), 40%AOP, 50%AOP, 60%AOP, respectively, were performed with 30%1RM(One repetition maximum)intensity of intermittent and continuous KAASTU-loaded deep-squat exercise. Wave plus wireless surface electromyography instrument was used to collect the surface EMG signals of the lower thigh muscle group. Root mean square (RMS) calculation was used to estimate muscle activity level. The normalized RMS values of the anterior thigh group and posterior thigh group were calculated by RMS of MVC, two-factor ANOVA analysis of variance were used to explore the effect of the activation of various muscle on external express and intermittent mode, to analyze the discrepancy during different external pressure. Results: ①A two-factor analysis of variance showed that different %AOP had significant effect on the normalized values of RMS of muscle measured by KAATSU deep-squat exercise(P＜0.05), but intermittent mode had no significant effect on the standard value of RMS of muscle(P＞0.05). The interaction of external pressure and intermittent mode on muscle RMS was not significant(P＞0.05); ②The normalized RMS values of Rectus Femoris, Vastus Medialis, Vastus Lateralis, Biceps Femoris, Semitendinosus were significantly increased (P＜0.05)in 50% AOP pressure condition during intermittent and continuous exercise; ③ The normalized RMS values of RF and VL were significantly increased(P＜0.05)in 50% AOP pressure condition during intermittent and continuous exercise. The %MVC values of Vastus Medialis and Semitendinosus were significantly increased(P＜0.05)in 60% AOP pressure condition during intermittent exercise. Conclusion: This study further verified that 50% AOP pressure can significantly improve the optimal activation quadriceps and posterior thigh groups and produce the best training effect for the high level handball players. It can not only promote the coordinated development of the agonist and antagonist, but also avoid overloading and prevent hamstring injury. At the same time, the intermittent mode is recommended to adopt the decompression intermittent mode.

Ankle Instability Patients Exhibit Altered Muscle Activation of Lower Extremity and Ground Reaction Force during Landing: A Systematic Review and Meta-Analysis.

This review aimed to investigate characteristics of muscle activation and ground reaction force (GRF) patterns in patients with ankle instability (AI). Relevant studies were sourced from PubMed, CINAHL, SPORTDiscus, and Web of Science through December 2019 for case-control study in any laboratory setting. Inclusion criteria for study selection were (1) subjects with chronic, functional, or mechanical instability or recurrent ankle sprains; (2) primary outcomes consisted of muscle activation of the lower extremity and GRF during landing; and (3) peer-reviewed articles with full text available, including mean, standard deviation, and sample size, to enable data reanalysis. We evaluated four variables related to landing task: (1) muscle activation of the lower extremity before landing, (2) muscle activation of the lower extremity during landing, (3) magnitude of GRF, and (4) time to peak GRF. The effect size using standardized mean differences (SMD) and 95% confidence intervals (CI) were calculated for these variables to make comparisons across studies. Patients with AI had a lower activation of peroneal muscles before landing (SMD = -0.63, p < 0.001, CI = -0.95 to -0.31), greater peak vertical GRF (SMD = 0.21, p = 0.03, CI = 0.01 to 0.40), and shorter time to peak vertical GRF (SMD = -0.51, p < 0.001, CI = -0.72 to -0.29) than those of normal subjects during landing. There was no significant difference in other muscle activation and GRF components between the patients with AI and normal subjects (p > 0.05). Altered muscle activation and GRF before and during landing in AI cases may contribute to both recurrent ankle and ACL injuries and degenerative change of articular.

Effects of NMES pulse width and intensity on muscle mechanical output and oxygen extraction in able-bodied and paraplegic individuals.

Neuromuscular Electrical Stimulation (NMES) is commonly used in neuromuscular rehabilitation protocols, and its parameters selection substantially affects the characteristics of muscle activation. Here, we investigated the effects of short pulse width (200µs) and higher intensity (short-high) NMES or long pulse width (1000µs) and lower intensity (long-low) NMES on muscle mechanical output and fractional oxygen extraction. Muscle contractions were elicited with 100Hz stimulation frequency, and the initial torque output was matched by adjusting stimulation intensity. Fourteen able-bodied and six spinal cord-injured (SCI) individuals participated in the study. The NMES protocol (75 isometric contractions, 1-s on-3-s off) targeting the knee extensors was performed with long-low or short-high NMES applied over the midline between anterior superior iliac spine and patella protrusion in two different days. Muscle work was estimated by torque-time integral, contractile properties by rate of torque development and half-relaxation time, and vastus lateralis fractional oxygen extraction was assessed by Near-Infrared Spectroscopy (NIRS). Torque-time integral elicited by the two NMES paradigms was similar throughout the stimulation protocol, with differences ranging between 1.4% (p = 0.877; able-bodied, mid-part of the protocol) and 9.9% (p = 0.147; SCI, mid-part of the protocol). Contractile properties were also comparable in the two NMES paradigms. However, long-low NMES resulted in higher fractional oxygen extraction in able-bodied (+ 36%; p = 0.006). Long-low and short-high NMES recruited quadriceps femoris motor units that demonstrated similar contractile and fatigability properties. However, long-low NMES conceivably resulted in the preferential recruitment of vastus lateralis muscle fibers as detected by NIRS.

Volleyball Data Analysis System and Method Based on Machine Learning

After the reform and the opening up, the economy of my country has grown rapidly and people’s lives have become better and better. As a result, there is a lot of time to pay attention to their health, which has promoted the rapid development of my country’s sports industry. Since the 2008 Beijing Olympics, the successful hosting of the Beijing Olympics has been further strengthened. With the rise of the development of sports in our country, the use of machine learning in a large amount of information can process this data and analyze it well. Based on this, this article is aimed at making volleyball players and coaches better understand the technical structure of hiking and the technique of hiking. The paper understands the characteristics of muscle activity over time and uses machine learning methods to analyze a large number of volleyball sports data. In this experiment, 12 volleyball players from a college of physical education were selected. According to the actual situation of the students’ physical fitness and skills, it is more reasonable to divide them into two arms with preswing technology (A type) group and two‐arms without preswing technology (B type) group. Mainly study the volleyball spiking action, select the representative front‐row 4th position strong attack and the back‐row 6th position for comparison and analysis, and analyze the process from the take‐off stage to the aerial shot stage in the four stages of the smash through the kinematics, dynamics, and surface electromyography parameters. Experiments have shown that for type A, the left gluteus maximus integral EMG sum value is significantly different between the front and rear rows (P &lt; 0.05). The discharge volume of the left gluteus maximus during the front‐row spiking process is greater than that of the back‐row spiking. This difference is mainly reflected in the kicking stage and the air attack stage. It shows that volleyball data analysis has a very broad prospect of exploration and application, which can create huge social and economic benefits. How to analyze kinematics is also a very demanding research project and is also part of the future analysis of sports data. Academic value and broad practical significance are important.

Surface electromyography of forearm and shoulder muscles during violin playing

The aims of this study were to explore muscle activity levels during different violin repertoires, quantify the general levels bilaterally in upper extremity muscles, and evaluate associations between muscle activity and anthropometrics characteristics. In 18 skilled violin players surface EMG was recorded bilaterally from trapezius (UT), flexor digitorum superficialis (FDS), extensor carpi ulnaris (ECU), extensor digitorum cummunis (EDC), and extensor carpi radialis (ECR) during A and E major scales played in three octaves and Mozart’s Violin Concerto no. 5. To compare side differences the static, median and peak levels of muscle activity were calculated from an amplitude probability distribution function (APDF). This study demonstrated that scales played as standardized tasks can be used to estimate the average muscle activity during violin playing. Comparing results from scales and the music piece revealed a similar muscle activity across all muscles in the music piece and E major scales. The static, median and peak EMG levels were higher in left than in right forearm muscles with left ECU presenting the highest peak load of 30 %MVE. Females demonstrated a higher muscle activity than males, but this was in accordance with differences in anthropometric measures.

Core Stability and Electromyographic Activity of the Trunk Musculature in Different Woman’s Sports

Volleyball players and gymnasts need strength training to achieve their optimum sport performance. The aims of this study were to describe body composition, strength, performance, and characteristics of trunk muscle activation in volleyball players and gymnasts, and to analyze the differences between the sports. The sample consisted of 40 female athletes: rhythmic gymnasts (n = 24; age 13.95 ± 2.77 years) and volleyball players (n = 16; age 19.81 ± 5.55 years). Body composition, maximum voluntary contraction (MVC) of isometric tests in an isokinetic dynamometer, McGill core endurance test, and surface electromyography (EMGrms) of the trunk muscle during the McGill test and isometric tests were recorded. Rhythmic gymnasts presented lower body composition values than volleyball players (p &lt; 0.05). The volleyball players presented higher isometric strength than rhythmic gymnasts in terms of MVC in trunk flexion (p &lt; 0.05, d = 1.3) and trunk extension (p &lt; 0.001, d = 1.3). EMGrms from the rhythmic gymnasts were greater for trunk flexor muscles (p &lt; 0.01, d = 0.7) and trunk extensor muscles (p &lt; 0.001, d = 1.3) during McGill endurance tests compared to the volleyball players. In the isometric test, EMGrms from the rhythmic gymnasts were greater for trunk flexor muscles in flexion (p &lt; 0.01, d = 0.9) and extension tests (p &lt; 0.05, d = 0.7). In conclusion, the volleyball players exhibited higher peak strength, despite the fact that the gymnasts showed greater muscle activity during the maximum voluntary contraction.

The Structure of Selected Basic Acrobatic Jumps.

The aim of this study was to investigate the relationships between the internal and external structure of basic acrobatic jumps. Eleven healthy elite artistic gymnasts (9 female, 2 male) participated in this study. Participants performed the following basic ‘acrobatic’ jumps: a tucked backward somersault (TS), a piked backward somersault (PS), and a countermovement jump (CMJ). Furthermore, female gymnasts also performed the backward handspring (HS), taking off and then landing on their hands in the same place – a specific jump only for women. All jumps were initiated from a stationary upright posture and with an arms swing. Six infrared cameras, synchronized with a module for wireless measurement of the electrical activity of eight muscles, and the force plate were used. Infrared camera-recordings were made in order to obtain kinematic variables describing the movement structure of the acrobatic jumps. These variables may explain the characteristics of muscle activation (the internal structure of the movement) and ground reaction force (the external-kinetic structure of the movement). However, for various technical reasons, it was not possible to register all the specified jumps in the protocol. Moreover, the distribution normalities, estimated by the Kolmogorov-Smirnov test, differed between variables. Therefore, to compare the data, the pair-wise nonparametric Wilcoxon Signed-Ranks Test was applied. The CMJ showed the highest level of vertical impulse, velocity, and displacement followed by the TS, PS, and HS. In the take-off phase of acrobatic jumps with rotation the average muscle activation levels of the biceps femoris were significantly higher and of the rectus femoris significantly lower than in the countermovement jump.

Effects of age and gender on swallowing activity assessed by electromyography and laryngeal elevation.

Quantitative assessment of swallowing function is necessary to prevent swallowing impairment due to ageing. Though surface electromyography (EMG) has been widely used to measure swallowing activity, the relationship between EMG results and swallowing function is unclear. This study examined the relationship between the temporal characteristics of muscle activity and laryngeal elevation (LE) during swallowing. This study analysed 60 healthy volunteers in two age groups (young, between 20 and 38years; old, between 65 and 75years), each containing the same number of male and female participants. Surface EMG signals were recorded from the suprahyoid and infrahyoid muscle groups (SH-EMG and IH-EMG, respectively). LE was measured using an array of pressure sensors. The participants swallowed 3mL of water under three swallowing speed conditions: fast, normal and slow swallowing. The EMG duration, EMG time intervals before and after the onset of LE (pre-LE and post-LE intervals, respectively), and the LE velocity were analysed. Both EMG duration and the post-LE interval of IH-EMG were significantly longer in the older group. As for the gender effect, the pre-LE interval of SH-EMG was significantly longer and the LE velocity was significantly higher in men than in women. Furthermore, there was a negative correlation between pre-LE interval and LE velocity in the fast swallowing condition. Though ageing slightly prolonged the muscle activity time, gender influenced swallowing activity in a more complex manner. Therefore, it is important to take gender into account when examining swallowing function with increasing age.

Moderate Exercise and the Psycho-Neural and Bio-Mechanical Nature of Chronic Low Back Pain

Low back pain (LBP) is one of the most common health problems, which in 10-15% of patients progresses to develop into a chronic low back pain (CLBP) condition, bringing enormous psychological and financial costs to the affected individuals, their families and society as a whole. There are many theories – pure bio-medical, bio-mechanical, psychological, as well as poly-modal ones, attempting to explain the pathology and aetiology of CLBP and guide its treatment. Although there is a general consensus that CLBP, as many other chronic pain conditions, is heterogeneous in nature, involving both organic (bio-mechanical and physiological) and psycho-social factors, there is still not a definite answer to the exact interactions and causative links between these factors. The present study employed a 15 minutes moderate treadmill exercise intervention in 10 CLBP sufferers and 10 healthy controls in order to further clarify the interactions between these physiological, bio-mechanical and psychological factors. The results from the present study, in accordance with previous research confirmed that CLBP participants are clearly identifiable according to their affective and cognitive profile - CLBP participants reported significantly higher levels of Pain Catastrophising (t = 3.81, p = .003), as well as Depression (t = 2.35, p = .03). Although both Pain Catastrophising and Depression were significantly correlated with the background pain (r = .755, p < .001 and r = .559, p = .010 respectively) in the CLBP group alone, contrary to previous CLBP studies, there were no significant associations between the background pain level and duration, Depression, Anxiety, Stress and even Pain Catastrophising. The Negative affective (NA) state was measured dynamically throughout the experiment and was reduced non-significantly by the exercise in both groups. Surprisingly, The NA was very low – 18 to 20 on a scale of 15 to 75, in both groups (even lower in the CLBP) and there was no significant difference between the NA of the CLBP and Control groups at any time-point of the experiment. The ES and MF back muscles activity was measured using a static standing and fully bent forward ratio, as well as flexion-relaxation ratio (FRR) pre- and post-exercise. The present study's results, although less robust than the results from previous research, confirmed that both standing and fully bent forward ES and MF measures, as well as FRR distinguished CLBP from control participants – CLBP had a higher level of static muscle activity (significant for the pre-exercise right MF in fully bent down position t = -2.48, p = . 044) and reduced FRR (significant for the pre-exercise left ES – t = 3.09, p = .013 and post-exercise left ES and right MF – t = 2.33, p = .038; t = 2.73, p = .032 respectively). Although the exercise produced non significant improvement of the ES and MF muscle activity, it also produced a divergent pain intensity (PPI) response between different CLBP participants – 5 (55.56%) had a decrease in PPI, while 4 (44.44%) had an increase. The pain decrease sub-group exhibited only a mild back muscles dysfunction, characterised by increased activity of the ES and MF in resting state (muscle tension), combined with a higher negative cognitive and affective mental set. The main characteristics of the pain increase sub-group was abnormal ES and MF flexion-relaxation, which pointed to compensatory increased activity of the superficial back muscles due to possible intrinsic spinal instability. In conclusion, the moderate treadmill exercise, utilised in the present study, was capable of identifying the existence of CLBP sub-groups, which were otherwise undistinguishable by the rest of their background pain, psychological or muscle activity characteristics. The low back pain of one of the sub-groups was associated with primary psychological top-down dysfunction of the 'active system' (muscles), while in the second sub-group the principal underlying factor identified was primary organic bio-mechanical dysfunction of the 'passive system'. The possible mechanisms and implications of this dichotomous nature of CLBP in respect to its aetiology, diagnosis, treatment and further research are discussed.

Does a recent hamstring muscle injury affect the timing of muscle activation during high speed overground running in professional Australian Football players?

ObjectivesTo investigate if the temporal characteristics of hamstring and gluteal muscle activation are altered during high speed overground running in professional Australian Football players following hamstring muscle injury. DesignCohort study. SettingField-based testing. ParticipantsElite professional Australian Football players who had sustained a hamstring muscle injury in the six months prior to testing (n = 7) and a group of players from the same club who had no history of hamstring muscle injury (n = 8). Main outcome measuresMuscle onset timing, muscle offset timing and muscle onset duration of the medial hamstrings, biceps femoris and gluteus maximus muscles during high-speed running using electromyographic data. ResultsNo significant differences in any of the temporal aspects of muscle activation were found between groups for any of the muscles tested (p > 0.05). ConclusionsPersistent alterations to the timing of muscle activation following hamstring muscle injury that have been reported in recreational athletes were not observed during high speed running in professional athletes who have completed comprehensive rehabilitation programs.

A Study on the Core Muscle Activation Characteristics of Suspension Training by Ground Type

A Study on the Core Muscle Activation Characteristics of Suspension Training by Ground Type

High day-to-day repeatability of lower extremity muscle activation patterns and joint biomechanics of dual-belt treadmill gait: A reliability study in healthy young adults

PurposeThe reliability of lower extremity muscle activation patterns has not been clearly studied in a dual-belt instrumented treadmill environment. The primary study objective was to quantify the day-to-day reliability of quadriceps, hamstrings, gastrocnemius and gluteus medius activation patterns in healthy young adult gait. Secondarily, the reliability of spatiotemporal, and knee/hip motion and moment-based gait outcomes was assessed.Scope: 20 young adults were recruited and tested on two separate days. Using standardized procedures, participants were prepared for surface electromyography and lower extremity motion capture. All individuals walked on a dual-belt instrumented treadmill while muscle activation, segment motions and ground reaction forces were recorded. Sagittal plane motion and net external sagittal and frontal plane moments were calculated. Discrete biomechanical and muscle activation measures were calculated, and non-negative matrix factorization extracted amplitude and temporal muscle activation features. Intraclass Correlation Coefficients, Standard Error of Measurement and Minimum Detectable Change were calculated. ConclusionsHigh to excellent Intraclass correlation coefficients were found between visits for most primary and secondary outcomes. The absolute and relative reliability, including Minimum Detectable Change values, provided in this study support the use of dual-belt instrumented treadmill walking as an acceptable medium to collect biomechanical and lower extremity EMG outcomes for future studies.

Characteristics of Lower Limb Muscle Activity in Elderly Persons After Ergometric Exercise.

This study examined the characteristics of lower limb muscle activity in elderly persons after ergometric pedaling exercise for 1 month. To determine the effect of the exercise, surface electromyography (SEMG) of lower limb muscles was subjected to Daubechies-4 wavelet transformation, and mean wavelet coefficients were compared with the pre-exercise coefficients and the post-exercise coefficients in each wavelet level. The characteristics of muscle activity after pedaling exercise were also compared between the elderly subjects and young subjects. For the elderly subjects, the mean wavelet coefficients were significantly decreased in the tibialis anterior and the gastrocnemius medialis at wavelet levels of 3, 4, and 5 (125–62.5, 62.5–31.25, and 31.25–15.625 Hz, respectively), by pedaling exercise. However, the mean power of wavelet levels of 2 and 3 (250–125 and 125–62.5 Hz) within the rectus femoris and the biceps femoris were significantly increased in the young subjects. The effect of pedaling exercise is different from the effects of heavy-resistance training. It was suggested that the muscle coordination, motor unit (MU) firing frequency, and firing fiber type of lower limb muscles are changed with the different characteristics between elderly and young persons by pedaling exercise for 1 month.

Characteristics of Sagittal Knee Joint Kinematics Dynamics and Quadriceps Muscle Activity during Stair Ascent and Descent in Patients after Total Knee Arthroplasty

Characteristics of Sagittal Knee Joint Kinematics Dynamics and Quadriceps Muscle Activity during Stair Ascent and Descent in Patients after Total Knee Arthroplasty

Head Movements and Neck Muscle Activity During Air Combat Maneuvering.

BACKGROUND: The aim of the study was to determine the characteristics of cervical muscle activity in different head movements when using helmet mounted display in air combat maneuvering.METHODS: Cervical EMG was measured with eight F/A-18 pilots using the Joint Helmet Mounted Cueing System (JHMCS) during air combat maneuvering. In-flight Gz acceleration and continuous head position were recorded. Muscular activity was compared between head movements in isolation and combined with torso movement. In addition, the effect of the direction of head movements and the use of head support of the ejection seat on muscle activity was determined.RESULTS: Muscular loading increased in the cervical flexors and extensors when using the torso during targeting beyond the field of vision in the neutral sitting posture; the difference was significant in the flexors, but activity levels were higher in the extensors. Cervical muscles are loaded to a lesser extent if the head is kept in a stable position during Gz loading. Muscular activity in the neck muscles was higher when the pilot was moving the head out of neutral posture rather than toward neutral posture. The use of the headrest as a support decreased muscle activity in the extensors, but resulted in higher activity in the flexor muscles.DISCUSSION: All analyzed conditions were significantly affected by an increase in Gz. An increase of muscle activity with torso movements is considered as a positive factor as it reflects maintained muscular support for the cervical spine. Presented results may be helpful when specific conditioning programs and cockpit ergonomics are developed for fighter pilots.Sovelius R, Mäntylä M, Huhtala H, Oksa J, Valtonen R, Tiitola L, Leino T. Head movements and neck muscle activity during air combat maneuvering. Aerosp Med Hum Perform. 2020; 91(1):26-31.

Joint Torque Closed-Loop Estimation Using NARX Neural Network Based on sEMG Signals

Joint torque estimation is of great significance for the research and clinical application of intelligent rehabilitation technology. This paper proposes a closed-loop model for joint torque estimation based on surface electromyography (sEMG). Combined with the physiological characteristics of muscle activation, a nonlinear autoregressive with eXogenous inputs(NARX) neural network model for joint torque estimation based on sEMG signals is established. In order to solve the drift phenomenon of torque estimation, a state-space framework is constructed by regarding NARX neural network based torque estimation model as state model and developing a measurement model by the easily measured joint angle signals. With the built state-space model, the extended Kalman filter (EKF) is used to realize the closed-loop filtering of the estimated torque. In order to test the accuracy of the proposed closed-loop joint torque estimation, 8 volunteers were recruited to perform elbow joint isotonic motion experiments under four kinds of loads. The test results show that the average normalized root mean square error (NRMSE) between the estimated values of closed-loop model and measurement values of all subjects under load-dependent, multi-load and load-independent tests are 0.1080± 0.0411, 0.1326± 0.0494 and 0.1674± 0.0661 respectively, which is significant better than the results of the open-loop model (0.2694± 0.1584 ( $p\! ), 0.2499± 0.1326 ( $p\! ) and 0.3435± 0.2061 ( $p\! )). The presented closed-loop model combines offline modeling and online filtering to achieve online estimation of joint torque, which ameliorates the problem that the estimated torque in the open-loop model deviates greatly from the actual values and improves the accuracy of joint torque estimation.

Muscle Activation Patterns During Movement Attempts in Children With Acquired Spinal Cord Injury: Neurophysiological Assessment of Residual Motor Function Below the Level of Lesion.

Introduction: Characterization of residual neuromotor capacity after spinal cord injury (SCI) is challenging. The current gold standard for measurement of sensorimotor function after SCI, the International Society for Neurological Classification of Spinal Cord Injury (ISNCSCI) exam, seeks to determine isolated intentional muscle activation, however many individuals with SCI exhibit intentional movements and muscle activation patterns which are not confined to specific joint or muscle. Further, isolated muscle activation is a feature of the neuromuscular system that emerges during development, and thus may not be an appropriate measurement standard for children younger than 6.Methods: We utilized neurophysiological assessment methodology, long studied in adult SCI populations, to evaluate residual neuromotor capacity in 24 children with SCI, as well as 19 typically developing (TD) children. Surface electromyography (EMG) signals were recorded from 11 muscles bilaterally, representing spinal motor output from all regions (i.e., cervical, thoracic, and lumbosacral), during standardized movement attempts. EMG records were subjectively analyzed based on spatiotemporal muscle activation characteristics, while the voluntary response index (VRI) was utilized for objective analysis of unilateral leg movement tasks.Results: Evidence of intentional leg muscle activation below the level of lesion was found in 11/24 children with SCI, and was classified based on activation pattern. Trace activation, bilateral (generalized) activation, and unilateral or isolated activation occurred in 32, 49, and 8% of movement tasks, respectively. Similarly, VRI analyses objectively identified significant differences between TD and SCI children in both magnitude (p < 0.01) and similarity index (p < 0.05) for all unilateral leg movement tasks. Activation of the erector spinae muscles, recorded at the T10–T12 vertebral level, was observed in all children with SCI, regardless of injury level or severity.Conclusions: Residual descending influence on spinal motor circuits may be present after SCI in children. Assessment of multi-muscle activation patterns during intentional movement attempts can provide objective evidence of the presence and extent of such residual muscle activation, and may provide an indicator of motor recovery potential following injury. The presence of residual intentional muscle activation has important implications for rehabilitation following pediatric-onset SCI.

Characteristics of Muscle Activity in the Lower Extremity during Stepping over Various Obstacle

Characteristics of Muscle Activity in the Lower Extremity during Stepping over Various Obstacle

Use of Pelvic Corrective Force With Visual Feedback Improves Paretic Leg Muscle Activities and Gait Performance After Stroke.

The purpose of this study was to examine the effects of combined pelvic corrective force and visual feedback during treadmill walking on paretic leg muscle activity and gait characteristics in individuals with post-stroke hemiparesis. Fifteen chronic stroke participants completed visual feedback only and combined pelvic corrective force and visual feedback conditions during treadmill walking. Each condition included: 1-minute baseline, 7-minute training with visual feedback only or additional pelvic corrective force, 1-minute post training, 1-minute standing break, and another 5-minute training. EMGs from the paretic leg muscles and step length were measured. Overground walking was evaluated before treadmill walking, immediately and 10 minutes after treadmill walking. Greater increases in integrated EMG of all muscles, except vastus medialis and tibialis anterior, were observed with the application of additional pelvic corrective force compared to visual feedback only during treadmill walking. Overground walking speed significantly increased after treadmill training with combined pelvic correction force and visual feedback, but was not significant for the visual feedback only condition. Voluntary weight shifting with additional pelvic corrective force enhanced paretic leg muscle activities and improved gait characteristics during walking. Individuals with post-stroke hemiparesis could adapt feedforward control and generalize the adaptation to overground walking.

Characteristics of scapular muscle activity in massive rotator cuff tear cases without elevating the upper limbs

Characteristics of scapular muscle activity in massive rotator cuff tear cases without elevating the upper limbs