Monitor Muscle Activity Research Articles

Measuring muscle activities during gym exercises with textile pressure mapping sensors

We present a wearable textile sensor system for monitoring muscle activity, leveraging surface pressure changes between the skin and compression garment. Our first prototype is based on an 8×16 element fabric resistive pressure mapping matrix with 1 cm spacial resolution and 50 fps refresh rate. We evaluate the prototype by monitoring leg muscles during realistic leg workouts in a gym out of the lab. The sensor covers the lower part of quadriceps of the user. The shape and movement of the two major muscles (vastus lateralis and medialis) are visible from the data visualizing during various exercises. With features extracted from spacial and temporal domains out of the pressure force mapping information, with 4 different leg exercises plus non-workout activities (relaxing, adjusting machines and walking), we have reached 81.7% average recognition accuracy on a fine-grain sliding window basis, 93.3% on an event basis, and 85.6% spotting F1-score. We further investigate the relationships between people’s perception of the exercise quality/difficulty and the variation and consistency of the force pattern. A second prototype is also developed with tether-free to explore various placements including upper-arm, chest and lower back; a brief comparison with arm-worn EMG shows our approach is comparable on the signal quality level.

Masseter Muscle Activity in Track and Field Athletes: A Pilot Study.

Teeth clenching has been shown to improve remote muscle activity (by augmentation of the Hoffmann reflex), and joint fixation (by decreased reciprocal inhibition) in the entire body. Clenching could help maintain balance, improve systemic function, and enhance safety. Teeth clenching from a sports dentistry viewpoint was thought to be important and challenging. Therefore, it is quite important to investigate mastication muscles’ activity and function during sports events for clarifying a physiological role of the mastication muscle itself and involvement of mastication muscle function in whole body movement. Running is a basic motion of a lot of sports; however, a mastication muscles activity during this motion was not clarified. Throwing and jumping operation were in a same situation. The purpose of this study was to investigate the presence or absence of masseter muscle activity during track and field events. In total, 28 track and field athletes took part in the study. The Multichannel Telemetry system was used to monitor muscle activity, and the electromyograms obtained were synchronized with digital video imaging. The masseter muscle activity threshold was set 15% of maximum voluntary clenching. As results, with few exceptions, masseter muscle activity were observed during all analyzed phases of the 5 activities, and that phases in which most participants showed masseter muscle activity were characterized by initial acceleration, such as in the short sprint, from the commencement of throwing to release in both the javelin throw and shot put, and at the take-off and landing phases in both jumps.

The biomechanical demands of manual scaling on the shoulders & neck of dental hygienists

The purpose of this study was to evaluate the postural and muscular demands placed on the shoulders and neck of dental hygienists when performing a simulated manual scaling task. Nineteen healthy female dental hygienists performed 30-min of simulated manual scaling on a manikin head in a laboratory setting. Surface electromyography was used to monitor muscle activity from several neck and shoulder muscles, and neck and arm elevation kinematics were evaluated using motion capture. The simulated scaling task resulted in a large range of neck and arm elevation angles and excessive low-level muscular demands in the neck extensor and scapular stabilising muscles. The physical demands varied depending on the working position of the hygienists relative to the manikin head. These findings are valuable in guiding future ergonomics interventions aimed at reducing the physical exposures of dental hygiene work.Practitioner Summary: Given that this study evaluates the physical demands of manual scaling, a procedure that is fundamental to dental hygiene work, the findings are valuable to identify ergonomics interventions to reduce the prevalence of work-related injuries, disability and the potential for early retirement among this occupational group.

Biophotonic Technique to Study Muscle Tissue Metabolism of Athletes

ABSTRACT.Near-infrared spectroscopy is an affordable technology that can be used in monitoring muscle oxygenation in exercise and sport setting. In this study, we presented a portable, wireless, multichannel near-infrared spectroscopy device for real-time monitoring of muscle activity. Wireless communication was applied to data transmission in order to avoid cumbersome wires, and the whole system is highly integrated. We took special care to eliminate motion artifact when designing the near-infrared spectroscopy sensor for attachment to human skin. In addition, the system is designed with a high sampling rate so as to monitor rapid oxygenation changes during muscle activity. The wireless near-infrared spectroscopy sensor was designed using commercially available electronic components that were mounted onto a 4-layer rigid-flexible printed circuit board. We performed in vivo experiments including arterial occlusion and isometric voluntary forearm muscle contraction among wrestlers and demonstrated that the...

Comparison of Core Muscle Activity Between Back Squat and Push Press

Previous research has been done exhibiting the fact that core strengthening leads to performance enhancement, postural improvement, and decreased risk of low back pain. There are a wide variety of exercises that aim to provide such training benefits. Previous studies have looked at the activation of core trunk muscles while performing sit-ups using different abdominal devices. To date, no known studies have looked at the activation of core trunk muscles compared between the back squat (SQ) and push press (PP), two traditional weightlifting movements. PURPOSE: The purpose of this study was to determine if there is a difference in muscle activation when performing a PP versus a SQ. METHODS: Male varsity athletes (n=10) who regularly trained with Olympic barbell (OB) performed seven to ten repetitions of a PP and a SQ set to a metronome at 50 cycles per minute for each repetition. Electrodes were placed on the Rectus Abdominis (RA), Erector Spinae (ES), and External Obliques (EO) muscles in order to monitor muscle activity through electromyography (EMG) with wireless transmitters. Subjects performed seven to ten repetitions of PP and SQ with the OB, in a randomize order at 30% of their 1RM. After finishing, subjects performed a maximum voluntary contraction (MVC) of a SQ. The SQ and PP lifts were normalized to the MVC voltage. Data was analyzed using paired T-tests. RESULTS: The results presented in the following table are expressed means +/- standard deviations as a percent of MVC.Table: No title available.Significant differences were observed for RA tested relative to %MVC when comparing the SQ to PP (p<.014). CONCLUSIONS: The results of this study suggest that muscle activity in the muscle group RA may be greater when performing a SQ versus PP.

Development of Next-generation Compression Apparel

Enjoyment and participation in physical activity is often hindered by fear of injury. In particular, the muscles and joints in the lower limbs suffer from a higher likelihood of injuries due to muscle and ligament overloading/straining. High-end compression gear is currently limited only to providing passive muscular and vascular exercise response. Smart Apparel introduces the integration of a pressure mapping system into a compression garment, further extending its functional support in a range of applications, from an indispensable training aid within competitive sports through to the health industry. The purpose of this research was to investigate the design considerations and developmental steps necessary in developing such a ‘Smart Garment’ for monitoring muscle and limb activity. It investigates the use of a novel approach to quantifying muscular exertion and loading through the measurement of surface pressures between a target muscular group and a compressive elastic garment. Surface pressure information about muscle loading is detected for both running and cycling, where the repeatable and quantifiable nature of the data aids in the modification of behaviours that predispose athletes to injury; thereby minimising injury risk, reducing recovery times, and maximising training potential.

Impact of functional appliances on muscle activity: a surface electromyography study in children.

BackgroundElectromyography (EMG) is the most objective tool for assessing changes in the electrical activity of the masticatory muscles.The purpose of the study was to evaluate the tone of the masseter and anterior temporalis muscles in growing children before and after 6 months of treatment with functional removable orthodontic appliances.Material/MethodsThe sample conisted of 51 patients with a mean age 10.7 years with Class II malocclusion. EMG recordings were performed by using a DAB-Bluetooth instrument (Zebris Medical GmbH, Germany). Recordings were performed in mandibular rest position, during maximum voluntary contraction (MVC), and during maximum effort.ResultsThe results of the study indicated that the electrical activity of the muscles in each of the clinical situations was the same in the group of girls and boys. The factor that determined the activity of the muscles was their type. In mandibular rest position and in MVC, the activity of the temporalis muscles was significantly higher that that of the masseter muscels. The maximum effort test indicated a higher fatigue in masseter than in temporalis muscles.ConclusionsSurface electromyography is a useful tool for monitoring muscle activity. A 6-month period of functional therapy resulted in changes in the activity of the masticatory muscles.

Motor imagery-based brain activity parallels that of motor execution: Evidence from magnetic source imaging of cortical oscillations

Motor imagery (MI) is a form of practice in which an individual mentally performs a motor task. Previous research suggests that skill acquisition via MI is facilitated by repetitive activation of brain regions in the sensorimotor network similar to that of motor execution, however this evidence is conflicting. Further, many studies do not control for overt muscle activity and thus the activation patterns reported for MI may be driven in part by actual movement. The purpose of the current research is to further establish MI as a secondary modality of skill acquisition by providing electrophysiological evidence of an overlap between brain areas recruited for motor execution and imagery. Non-disabled participants (N=18; 24.7±3.8 years) performed both execution and imagery of a unilateral sequence button-press task. Magnetoencephalography (MEG) was utilized to capture neural activity, while electromyography used to rigorously monitor muscle activity. Event-related synchronization/desynchronization (ERS/ERD) analysis was conducted in the beta frequency band (15–30Hz). Whole head dual-state beamformer analysis was applied to MEG data and 3D t-tests were conducted after Talairach normalization. Source-level analysis showed that MI has similar patterns of spatial activity as ME, including activation of contralateral primary motor and somatosensory cortices. However, this activation is significantly less intense during MI (p<0.05). As well, activation during ME was more lateralized (i.e., within the contralateral hemisphere). These results confirm that ME and MI have similar spatial activation patterns. Thus, the current research provides direct electrophysiological evidence to further establish MI as a secondary form of skill acquisition.

A portable multi-channel wireless NIRS device for muscle activity real-time monitoring.

Near-infrared spectroscopy (NIRS) is a relative new technology in monitoring muscle oxygenation and hemo-dynamics. This paper presents a portable multi-channel wireless NIRS device for real-time monitoring of muscle activity. The NIRS sensor is designed miniaturized and modularized, to make multi-site monitoring convenient. Wireless communication is applied to data transmission avoiding of cumbersome wires and the whole system is highly integrated. Special care is taken to eliminate motion artifact when designing the NIRS sensor and attaching it to human skin. Besides, the system is designed with high sampling rate so as to monitor rapid oxygenation changes during muscle activities. Dark noise and long-term drift tests have been carried out, and the result indicates the device has a good performance of accuracy and stability. In vivo experiments including arterial occlusion and isometric voluntary forearm muscle contraction were performed, demonstrating the system has the ability to monitor muscle oxygenation parameters effectively even in exercise.

A Portable Powered Knee-Ankle- Foot Orthosis1

A Portable Powered Knee-Ankle- Foot Orthosis1

Multifunctional wearable devices for diagnosis and therapy of movement disorders

Wearable systems that monitor muscle activity, store data and deliver feedback therapy are the next frontier in personalized medicine and healthcare. However, technical challenges, such as the fabrication of high-performance, energy-efficient sensors and memory modules that are in intimate mechanical contact with soft tissues, in conjunction with controlled delivery of therapeutic agents, limit the wide-scale adoption of such systems. Here, we describe materials, mechanics and designs for multifunctional, wearable-on-the-skin systems that address these challenges via monolithic integration of nanomembranes fabricated with a top-down approach, nanoparticles assembled by bottom-up methods, and stretchable electronics on a tissue-like polymeric substrate. Representative examples of such systems include physiological sensors, non-volatile memory and drug-release actuators. Quantitative analyses of the electronics, mechanics, heat-transfer and drug-diffusion characteristics validate the operation of individual components, thereby enabling system-level multifunctionalities.

Examination of muscle activity with an elastic hamstring assistance device

Background: Hamstring injuries are common among athletes and recreationally active people. The goal of the study was to determine if the Hamstrong device was effective in reducing the activity of the hamstring muscles during isometric knee exercise. Materials and Methods: Electrodes were placed on the biceps femoris and semitendinosus in a bipolar configuration on the left leg of all the subjects (N = 12) in order to monitor muscle activity during the experimental procedure. The test involved isometrically holding 15%, 30%, 45%, and 60% of the participant's pre-determined maximum isometric force at 90° and 135° knee extension with and without the Hamstring apparatus. The raw electromyography (EMG) signal was low-pass filtered and amplified prior to being interpreted. Results: There was a significant difference in the signal from the biceps femoris determined via surface electromyography (sEMG) at 90 degrees of knee extension using 30% of peak isometric force as the load (P = 0.043). Additionally in the biceps femoris there were differences in the sEMG signal at 135 degrees of knee extension using 15% (P = 0.0492) and 30% (P = 0.0358) of peak isometric force. In the semitendinosus muscle, there was a significant difference in sEMG signal at 15° of knee extension with 60% of peak isometric force (P = 0.0025). Overall, clinical inferences revealed that the device could be considered 71.4% beneficial or substantially positive to 10.9% for reducing the EMG signal associated with isometric exercise in the biceps femoris (biceps femoris mean: With device 0.319 mV ± 0.13 and without device 0.361 mV ± 0.14). Similarly, six out of eight conditions resulted in lower muscle activation from the semitendinosus with the apparatus. For the semitendinosus muscle, the range was from 43.9% beneficial to 0.1% beneficial (semitendinosus mean: With device 0.327 mV ± 0.09 and without device 0.339 mV ± 0.09). Conclusion: The reduction in electrical activity of the biceps femoris and the semitendinosus during the isometric hold with the Hamstring apparatus suggests that the elastic hamstring assistance device effectively assists in knee flexion and could potentially be used for rehabilitation purposes.

Bioimpedance system for monitoring muscle and cardiovascular activity in the stump of lower-limb amputees

A bioimpedance system for the continuous measurement of non-invasive physiological parameters in lower-limb amputees is presented. The aim of the system is to monitor as many physiological parameters as possible from a single bioimpedance electrode configuration. In this way, a simple, low-cost and low-size autonomous system is developed that is able to continuously monitor the amputee in different environments (home, work, etc). The system measures both electrical impedance myography and electrical impedance plethysmography in the stump with electrodes placed in the inside face of a silicone interface. Such a system allows for the monitoring of a patient's muscle activity, and heart and breath rate, thus enabling the study and continuous monitoring of prosthesis adaptation and improvement of patient's gait to reduce physiological stress. Additionally, it can prevent cardiovascular problems due to the effort involved in the use of prostheses, which can decrease the life expectancy of amputees with previous vascular diseases. Experimental results obtained from different amputees' test validate the purpose of the system.

C203 筋音・筋電センサを用いた筋状態評価用センサシステムに関する研究(C2-1 生体計測1)

C203 筋音・筋電センサを用いた筋状態評価用センサシステムに関する研究(C2-1 生体計測1)

Afferent Contribution to Locomotor Muscle Activity During Unconstrained Overground Human Walking: An Analysis of Triceps Surae Muscle Fascicles

Plantar flexor series elasticity can be used to dissociate muscle-fascicle and muscle-tendon behavior and thus afferent feedback during human walking. We used electromyography (EMG) and high-speed ultrasonography concomitantly to monitor muscle activity and muscle fascicle behavior in 19 healthy volunteers as they walked across a platform. On random trials, the platform was dropped (8 cm, 0.9 g acceleration) or held at a small inclination (up to +/-3 degrees in the parasagittal plane) with respect to level ground. Dropping the platform in the mid and late phases of stance produced a depression in the soleus muscle activity with an onset latency of about 50 ms. The reduction in ground reaction force also unloaded the plantar flexor muscles. The soleus muscle fascicles shortened with a minimum delay of 14 ms. Small variations in platform inclination produced significant changes in triceps surae muscle activity; EMG increased when stepping on an inclined surface and decreased when stepping on a declined surface. This sensory modulation of the locomotor output was concomitant with changes in triceps surae muscle fascicle and gastrocnemius tendon length. Assuming that afferent activity correlates to these mechanical changes, our results indicate that within-step sensory feedback from the plantar flexor muscles automatically adjusts muscle activity to compensate for small ground irregularities. The delayed onset of muscle fascicle movement after dropping the platform indicates that at least the initial part of the soleus depression is more likely mediated by a decrease in force feedback than length-sensitive feedback, indicating that force feedback contributes to the locomotor activity in human walking.

Utility of Portable Electromyography for Quantifying Muscle Activity during Daily Use

Background: Mobility has been studied using performance, questionnaire, pedometer and accelerometer measures, but these tools do not provide information about muscle activity. To better understand mechanisms associated with movement impairment as they relate to function, it is valuable to quantify muscle activity during everyday activities. Objective: This report presents electromyography (EMG) during daily activities from the affected and unaffected limbs of a 74-year-old man who survived a stroke 12 years ago, compared to 7 older healthy men who had not experienced a stroke. Methods: The biceps brachii, triceps brachii, quadriceps and hamstring muscles were recorded continuously for one 8-hour session in the unaffected limbs of the stroke survivor and control subjects. On a second day, EMG from these same muscles of the affected side was recorded for 4 h. Bursts (amplitude >2% maximum effort, duration >0.1 s) and gaps (amplitude <1% maximum effort, duration >0.1 s) of EMG were quantified for the number of times they occurred, mean event duration (seconds), mean peak amplitude (percent maximum voluntary efforts) and rate of activity (event activity/second). Results: Burst and gap patterns of the unaffected limb muscles were similar between the stroke survivor and controls. Increased numbers of bursts (approx. 40%) and gaps (approx. 44%) were seen in the subject’s lower limb muscles of his affected versus unaffected side. Biceps brachii burst activity of the affected limb was increased, whereas triceps brachii burst activity was decreased. These muscle activity changes in the affected limb suggest that the triceps brachii was relatively inactive and the biceps brachii and lower limb muscles were active in an ‘on’ and ‘off’ pattern. Conclusion: Muscle activity in the unaffected limb of the stroke survivor was similar compared to control subjects, but the affected limb differed from the unaffected after stroke. Portable EMG to monitor muscle activity for prolonged periods was not reported to be an impediment by the case or control subjects. Using this technology, EMG bursts and gaps can be recorded and used to describe muscle activity. Future work may consider the feasibility of this technique to monitor rehabilitation progression or long-term plasticity of muscle activity.

Contractile Properties of Single Permeabilized Muscle Fibers from Congenital Cleft Palates and Normal Palates of Spanish Goats

Analysis of the composition of muscle fibers constituent to a cleft palate could provide significant insight into the cause of velopharyngeal inadequacy. The authors hypothesized that levator veli palatini muscle dysfunction inherent to cleft palates could affect the timing and outcome of cleft palate repair. Single, permeabilized muscle fibers from levator veli palatini muscles of three normal (n = 19 fibers) and three chemically induced congenital cleft palates (n = 21 fibers) of 14-month-old goats were isolated, and contractile properties were evaluated. The maximum isometric force and rate constants of tension redevelopment (ktr) were measured, and the specific force and normalized power were calculated for each fiber. The ktr measures indicate that cleft fibers are predominantly fast-fatigable; normal fibers are slow fatigue-resistant: after a 10-minute isometric contraction, fibers from cleft palates had a loss of force 16 percent greater than that from normal palates (p = 0.0001). The cross-sectional areas of the fibers from cleft palates (2750 +/- 209 microm2) were greater (p = 0.05) than those from normal palates (2226 +/- 143 microm2). Specific forces did not differ between the two groups. Maximum normalized power of fibers from cleft palates (11.05 +/- 1.82 W/l) was greater (p = 0.0001) than fibers from normal palates (1.60 +/- 0.12 W/l). There are clear physiologic differences in single muscle fibers from cleft palates and normal palates: cleft palate fibers are physiologically fast, have greater fatigability, and have greater power production. Detection of functional and/or fiber type differences in muscles of cleft palates may provide preoperative identification of a patient's susceptibility to velopharyngeal inadequacy and permit early surgical intervention to correct this clinical condition.

Revealing Bioelectric Muscle Activity Corrupted by Superimposed Magnetic Resonance Field

Most clinical measurements rely on bioelectromagnetic phenomena. These events allow us to record electric or magnetic signals during the activity of living tissues. In this paper, we put our attention on the bioelectric fields that occur in the muscle activity. In fact during the body movements, the muscle contractions produce a bioelectric potential distribution that can be measured by putting the electrodes on the skin. In clinical applications, the monitoring of muscle activity can be performed in a noninvasive way, by placing a fixed number of electrodes on the skin surface; this technique is called surface electromyography (sEMG), and it is able to reveal the electric field generated by each muscle activity. Unfortunately, the sEMG suffers from the external electromagnetic fields. In recent years, many authors investigated the correlation between muscle and brain activity by performing the sEMG during the functional magnetic resonance imaging (fMRI). The fMRI is the most reliable technique to evaluate the brain activity because it allows us to obtain some images of the human body with very high resolutions. Unfortunately, joint measurement is a very difficult task because of the high electromagnetic interference between the resonance coils (very high magnetic fields) and the sEMG electrodes. In this paper, we present a method based on wavelet analysis to reveal sEMG in voluntary contractions when the measurement is made in a fMRI environment

Strategies to identify changes in SEMG due to muscle fatigue during cycling

Detection, quantification and analysis of muscle fatigue are crucial in occupational/rehabilitation and sporting settings. Sports organizations such as the Australian Institute of Sports (AIS) currently monitor fatigue by a battery of tests including invasive techniques that require taking blood samples and/or muscle biopsies, the latter of which is highly invasive, painful, time consuming and expensive. SEMG is non-invasive monitoring of muscle activation and is an indication of localized muscle fatigue based on the observed shift of the power spectral density of the SEMG. But the success of SEMG based techniques is currently limited to isometric contraction and is not acceptable to the human movement community. This paper proposes and tests the use of spectral analysis of narrow windows of SEMG near the peak of a cyclic activity to identify the onset of muscle fatigue during cyclic activities. The results demonstrate a highly significant relationship of reduction of the median frequency with the onset of muscle fatigue. The paper also reports the validation of the SEMG study using biochemical analysis of muscle biopsy and blood tests and further verified using power output of the cycle and speed of pedalling.

5526 筋活動状態測定用小型筋音センサの開発(S86-2 生物医学工学における計測と制御(2),S86 生物医学工学における計測と制御)

5526 筋活動状態測定用小型筋音センサの開発(S86-2 生物医学工学における計測と制御(2),S86 生物医学工学における計測と制御)