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1
Doede, Aubrey L. "Electromyographic Analysis of Trunk Muscle Activation During a Throwing Pattern Following Rotator Cuff Mobilization." Scholarship @ Claremont, 2010. http://scholarship.claremont.edu/cmc_theses/90.
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Correct muscular activation of the body segments during an overhand throw is achieved when movement originates in the larger and more proximal legs and trunk and moves sequentially to the smaller, distal segments of the shoulder and arm. This sequence permits angular velocity to transfer progressively through the throw as part of an open kinetic chain. The athlete can summate angular velocity and segmental forces only if he is able to create a separation between the body segments during the movement pattern, and this separation is thus essential to effective segmental sequencing for activation of the trunk muscles to occur separately from distal segment motion. Limited mobility of the shoulder and scapula during the kinematic sequence will limit the ability of that segment to receive and contribute to the angular velocity of its proximal neighbors and to apply its own muscle torque to the throwing implement. This may result in compensatory motion of the proximal muscle groups to meet the demands placed on the body. To establish a link between compensatory activation of the trunk muscles and mobility in the rotator cuff and to apply this relationship to the pattern of the overhand throw, activity in the latissimus dorsi and external oblique/quadratus lumborum muscles was measured using surface electromyography in 40 college-age participants during arm flexion and lateral shoulder rotation. Muscle activation was recorded both before and after mobilization of relevant throwing muscles through targeted functional exercise. Results showed no significant change but suggested a general decrease in the level of peak muscle activation after participants engaged shoulder exercises. This is indicative of a downward trend in compensatory trunk activation during the initiation of shoulder motion. An increase in overall trunk muscle activity was also observed after exercise, which may imply a simultaneous engagement of the proximal throwing muscles in response to shoulder motion.
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Fung, Joyce. "The muscle activation and reflex modulation pattern during locomotion in normal and spastic paretic subjects." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39327.
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The lower limb electromyographic (EMG) patterns of 5 normal and 8 spastic paretic subjects during walking were compared. A dynamic EMG profile index, proposed to quantify spastic locomotor dysfunction, was found to be homogeneously low in normal subjects and abnormally high in spastic subjects. In another study, the normally phase-dependent modulation of the soleus H-reflex during walking was found to be decreased or absent in 21 spastic paretic subjects, suggesting the possibility of defective reflex gating mechanisms. The conditioning effects of plantar cutaneomuscular stimulation were further examined in 10 normal and 10 spastic paretic subjects. The conditioned H-reflex was inhibited in a task and phase-dependent manner, such that the effects were most marked during early stance and swing, restoring a near normal modulation pattern during walking in the severely spastic subjects who showed no modulation previously. The possible underlying mechanisms and implications for rehabilitation are discussed.
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Lucas, Karen Rae, and karen lucas@rmit edu au. "The Effects of Latent Myofascial Trigger Points on Muscle Activation Patterns During Scapular Plane Elevation." RMIT University. Health Sciences, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080408.144402.
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Despite a paucity of experimental evidence, clinical opinion remains that though LTrPs allow pain-free movement, they are primarily associated with deleterious motor effects and occur commonly in 'healthy' muscles. The primary aim of this study was to investigate the effects of LTrPs on the muscle activation patterns (MAPs) of key shoulder girdle muscles during scapular plane elevation of the arm in the unloaded, loaded and fatigued states. In connection with the main aim, a preliminary study was carried out to examine the frequency with which LTrPs occur in the scapular positioning muscles in a group of normal subjects. After establishing intra-examiner reliability for the clinical examination process, 154 healthy subjects volunteered to be screened for normal shoulder girdle function, then undergo a physical examination for LTrPs in the trapezius, rhomboids, levator scapulae, serratus anterior and the pectoralis minor muscles bilaterally. Of these 'healthy' subjects, 89.8% had at least one LTrP in the scapular positioning muscles (mean=10.65 ± 6.8, range=1-27), with serratus anterior and upper trapezius harbouring the most LTrPs on average (2.46 ± 1.8 and 2.36 ± 1.3 respectively). Consistent with clinical opinion, this study found that LTrPs occur commonly in the scapular positioning muscles. To investigate the motor effects of LTrPs, surface electromyography (sEMG) was used to measure the timing of muscle activation of the upper and lower trapezius and serratus anterior (upward scapular rotators), the infraspinatus (rotator cuff) and middle deltoid (arm abductor). These studies found that LTrPs housed in the scapular upward rotator muscles affected the timing of activation and increased the variability of the activation times of this muscle group and were also associated with altered timing of activation in the functionally related but LTrP-free infraspinatus and middle deltoid. Compared with the control group (all muscles LTrP-free), the MAPs of the LTrP group appeared to be sub-optimal, particularly in relation to preserving the subacromial space and the loading of the rotator cuff muscles. After the initial sEMG evaluations, the LTrP subjects were randomly assigned to one of two interventions: superficial dry needling (SDN) followed by post-isometric relaxation (PIR) stretching to remove LTrP s or sham ultrasound, to act as a placebo treatment where LTrPs remained. Where LTrPs were removed, a subsequent sEMG evaluation found MAPs to be similar to the control group in most of the experimental conditions investigated. Of particular note, when LTrPs had been treated and the subjects repeated the fatiguing protocol, the resultant MAP showed no significant difference with that of the control group in the rested state, suggesting treating LTrPs was associated with an improved response to fatigue induced by repetitive overhead movements. In conclusion, the findings indicate that LTrPs commonly occur in scapular positioning muscles and have deleterious effects on MAPs employed to perform scapular plane elevation and thus affect motor control mechanisms. Treating LTrPs with SDN and PIR stretching increases pressure-pain thresholds, removes associated taut bands and at least transiently optimises the MAP during scapular plane elevation. Discussion includes possible neuromuscular pathophysiology that might explain these results.
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Davenport, Mary Jo. "The Effect of Sternocleidomastoid Muscle Activation Pattern and Feedback Condition on the Vestibular Evoked Myogenic Potential." Digital Commons @ East Tennessee State University, 2010. https://dc.etsu.edu/etd/1776.
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The vestibular evoked myogenic potential (VEMP) has been shown to be clinically useful in providing diagnostic information regarding the function of the otolith receptors, inferior vestibular nerve, and vestibulospinal pathways. The VEMP is a biphasic response elicited by loud clicks or tone bursts and recorded from the tonically contracted sternocleidomastoid (SCM) muscle. Because the VEMP is an inhibitory response, it is important to investigate stimulus and parameter characteristics in order to determine the optimal test protocol and maximize clinical usefulness. The aims of this study were 1) to evaluate the effects of 4 different methods of SCM muscle activation and the effect of visual biofeedback on VEMP latency, amplitude, asymmetry ratio, mean rectified EMG level, and difficulty ratings, and 2) to determine the influence of SCM muscle activation pattern and visual biofeedback level on test-retest reliability. Forty-eight healthy volunteers between the ages of 18 and 50 underwent VEMP testing using each of the following muscle activation patterns: supine with the head raised (SE), supine with the head turned away from the test ear (SR), supine with the head raised and turned away from the test ear (SER), and sitting with the head turned away from the test ear (SitR). Testing subjects with the SER method yielded the most robust amplitude response and sternocleidomastoid EMG activity. No statistically significant differences were found in interaural asymmetry ratios among the 4 methods of SCM activation. Subjects rated the SE and SER methods as more difficult than the SE and SitR methods at each of the 3 target levels. Test-retest reliability was high for P1/N1 amplitude and mean rectified EMG levels when subjects were provided visual biofeedback to monitor the level of tonic SCM muscle activity. The study demonstrates the importance of providing patients a means of monitoring and maintaining the amplitude of the rectified EMG at a constant target level during SCM muscle activation. Although no evidence to reject or strongly favor a specific method was found, monaural-ipsilateral recording with the SitR method was found to be advantageous for individuals with weakness or decreased endurance for sustained muscle contraction.
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BURNS, Jack, and jack burns@ecu edu au. "Does training with PowerCranks(tm) affect economy of motion, cycling efficiency, oxygen uptake and muscle activation patterns in trained cyclists?" Edith Cowan University. Computing, Health And Science: School Of Exercise, Biomedical & Health Science, 2008. http://adt.ecu.edu.au/adt-public/adt-ECU2008.0017.html.
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PowerCranks(tm) are claimed to increase economy of motion and cycling efficiency by reducing the muscular recruitment patterns that contribute to the resistive forces occurring during the recovery phase of the pedal stroke. However, scientific research examining the efficacy of training with PowerCranks(tm) is lacking. Therefore, the purpose of this study was to determine if five weeks of training with PowerCranks(tm) improves economy of motion (EOM), gross efficiency (GE), oxygen uptake (V.O2) and muscle activation patterns in trained cyclists. Sixteen trained cyclists were matched and paired into either a PowerCranks(tm) (PC) or Normal Cranks (NC) training group. Prior to training, all subjects completed a graded exercise test (GXT) using normal bicycle cranks. Additionally, on a separate day the PC group performed a modified GXT using PowerCranks? and cycled only until the end of the 200W stage (PCT). During the GXT and PCT, FeO2, FeCO2 and V.E were measured to determine EOM, GE and V.O2max. Integrated electromyography (iEMG) was also used to examine selected muscular activation patterns. Subjects then repeated the tests following the completion of training on their assigned cranks.
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Burns, Jack. "Does training with PowerCranks™ affect economy of motion, cycling efficiency, oxygen uptake and muscle activation patterns in trained cyclists?" Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2008. https://ro.ecu.edu.au/theses/17.
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PowerCranks™ are claimed to increase economy of motion and cycling efficiency by reducing the muscular recruitment patterns that contribute to the resistive forces occurring during the recovery phase of the pedal stroke. However, scientific research examining the efficacy of training with PowerCranks™ is lacking. Therefore, the purpose of this study was to determine if five weeks of training with PowerCranks™ improves economy of motion (EOM), gross efficiency (GE), oxygen uptake (V.O2) and muscle activation patterns in trained cyclists. Sixteen trained cyclists were matched and paired into either a PowerCranks™ (PC) or Normal Cranks (NC) training group. Prior to training, all subjects completed a graded exercise test (GXT) using normal bicycle cranks. Additionally, on a separate day the PC group performed a modified GXT using PowerCranks™ and cycled only until the end of the 200W stage (PCT). During the GXT and PCT, FeO2, FeCO2 and V.E were measured to determine EOM, GE and V.O2max. Integrated electromyography (iEMG) was also used to examine selected muscular activation patterns. Subjects then repeated the tests following the completion of training on their assigned cranks.
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Harischandra, Nalin. "Computer Simulation of the Neural Control of Locomotion in the Cat." Licentiate thesis, Stockholm : Numerisk analys och datalogi, Numerical Analysis and Computer Science, Kungliga Tekniska högskolan, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4692.
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Hovorka, Christopher Francis. "Influencing motor behavior through constraint of lower limb movement." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54903.
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Limited knowledge of the neuromechanical response to use of an ankle foot orthosis-footwear combination (AFO-FC) has created a lack of consensus in understanding orthotic motion control as a therapeutic treatment. Lack of consensus may hinder the clinician’s ability to target the motion control needs of persons with movement impairment (e.g., peripheral nerve injury, stroke, etc.). Some evidence suggests a proportional relationship between joint motion and neuromuscular activity based on the notion that use of lower limb orthoses that constrain joint motion may invoke motor slacking and decreasing levels of muscle activity.
Use of AFO-FCs likely alters the biomechanical and neuromuscular output as the central control system gradually forms new movement patterns. If there is proportional relationship between muscle activation and joint motion, then it could be examined by quantifying joint motion and subsequent neuromuscular output. Considering principles of neuromechanical adjustment, my general hypothesis examines whether orthotic control of lower limb motion alters neuromuscular output in proportion to the biomechanical output as a representation of the limb’s dynamics are updated by the neural control system. The rationale for this approach is that reference knowledge of the neuromechanical response is needed to inform clinicians about how a person responds to walking with motion controlling devices such as ankle foot orthoses combined with footwear.
In the first line of research, I hypothesize that a newly developed AFO which maximizes leverage and stiffness will constrain the talocrural joint and alter joint kinematics and ground reaction force patterns. To answer the hypothesis, I sampled kinematics and kinetics of healthy subjects’ treadmill walking using an AFO-FC in a STOP condition and confirmed that the AFO substantially limited the range of talocrural plantarflexion and dorsiflexion motion to 3.7° and in a FREE condition maintained talocrural motion to 24.2° compared to 27.7° in a CONTROL (no AFO) condition. A follow up controlled static loading study sampled kinematics of matched healthy subjects limbs and cadaveric limbs in the AFO STOP and FREE conditions. Findings revealed healthy and cadaveric limbs in the AFO STOP condition substantially limited their limb segment motion similar to matched healthy subjects walking in the STOP condition and in the AFO FREE condition healthy and cadaveric limbs maintained similar limb segment motion to matched healthy subjects walking in the FREE condition. In a second line of research, I hypothesize that flexibility of a newly developed footwear system will allow normal walking kinetics due to the shape and flexibility of the footwear. To answer the hypothesis, I utilized a curved-flexible footwear system integrated with an AFO in a STOP condition and sampled kinematics and kinetics of healthy subjects during treadmill walking. Results revealed subjects elicited similar cadence, stance and swing duration and effective leg-ankle-foot roll over radius compared to walking in the curved-flexible footwear integrated with the AFO in a FREE condition and a CONTROL (no AFO) condition. To validate rollover dynamics of the curved-flexible footwear system, a follow up study of healthy subjects’ treadmill walking in newly developed flat-rigid footwear system integrated with the AFO in a STOP condition revealed interrupted leg-ankle-foot rollover compared to walking in curved-flexible footwear in STOP, FREE and CONTROL conditions. In a third line of research, I hypothesize that use of an AFO that limits talocrural motion in a STOP condition will proportionally reduce activation of Tibialis Anterior, Soleus, Medial and Lateral Gastrocnemii muscles compared to a FREE and CONTROL condition due to alterations in length dependent representation of the limb’s dynamics undergoing updates to the central control system that modify the pattern of motor output. To answer the question, the same subjects and AFO-footwear presented in the first two lines of research were used in a treadmill walking protocol in STOP, FREE, and CONTROL conditions. Findings revealed the same subjects and ipsilateral AFO-footwear system presented in Aim 1 exhibited an immediate yet moderate 30% decline in EMG activity of ipsilateral Soleus (SOL), Medial Gastrocnemius (MG) and Lateral Gastrocnemius (LG) muscles in the STOP condition compared to the CONTROL condition. The reduction in EMG activity in ipsilateral SOL, MG and LG muscles continued to gradually decline during 15 minutes of treadmill walking. On the contralateral leg, there was an immediate yet small increase of 1% to 14% in EMG activity in SOL, MG, LG muscles above baseline. After 10 minutes of walking, the EMG activity in contralateral SOL, MG and LG declined to a baseline level similar to the EMG activity in the contralateral CONTROL condition. These collective findings provide compelling evidence that the moderate 30% reduction in muscle activation exhibited by subjects as they experience substantial (85%) constraint of total talocrural motion in the AFO STOP condition is not proportionally equivalent. Further, the immediate decrease in muscle activation may be due to a reactive feedback mechanism whereas the continued decline may in part be explained by a feedforward mechanism. The clinical relevance of these findings suggests that short term use of orthotic constraint of talocrural motion in healthy subjects does not substantially reduce muscle activation. These preliminary findings could be used to inform the development of orthoses and footwear as therapeutic motion control treatments in the development of motor rehabilitation protocols.
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Kyle, Natasha Flemming. "Muscle activation patterns during gait initiation." Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/27147.
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Gait initiation is a temporary movement between upright posture and steady-state gait. The activation of several postural muscles has been identified to precede changes observed in vertical reaction force. Previous research examining gait initiation has concentrated on the electromyographic activity of muscles of the lower limbs. Few studies, however, have looked at recruitment patterns of the muscles of the thigh and trunk. This study was conducted to determine the recruitment patterns and the roles of certain muscles of the trail and lead lower limbs and trunk for the duration from quiet stance to trail leg toe-off. Eleven healthy participants initiated gait with their right leg. Electromyographic data were collected bilaterally from the erector spinae, tensor fasciae latae, adductor magnus and tibialis anterior muscles. In addition, force platform data were recorded for the duration of quiet stance to toe-off of the trail limb. (Abstract shortened by UMI.)
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Gabriel, David Abraham. "Muscle activation patterns for goal-directed multijoint arm movements." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28748.
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The purpose of this dissertation was to determine if the CNS produces relatively simple alterations in muscle activity to accomplish goal-directed reaching motions of the upper limb under a variety of movement conditions.To this end, six subjects performed goal-directed arm movements in the horizontal plane. Two movement amplitudes (300 mm and 400 mm) were completed at a moderate speed (1050 mm/s) and as-fast-as possible. The speed and amplitude conditions were repeated for the 45$ sp circ$ and 90$ sp circ$ movement directions. Finally, each of the movement conditions mentioned thus far, were performed within the right and left sections of the work-space. Surface electro-myographic activity was recorded from the pectoralis major, posterior deltoid, biceps brachii short head, brachioradialis, triceps brachii long head, and triceps brachii lateral head. Motion recordings were obtained with a spatial imaging system that monitored the positions of infrared emitting diodes attached to the subject's upper arm and forearm-hand complex.
Several simplification schemes were found to be operative at the level of the electro-myogram. These include: (a) simple timing relationships for agonists between joints and agonist/antagonist intermuscle latencies within each joint; (b) tightly coupled timing between agonists within a single joint; (c) for a particular movement direction, the form and shape of EMG burst activity followed a strategy associated with modulation of pulse height and width; (d) the slope, duration, and onset were further affected by the direction of hand movement which resulted in the greatest RMS-EMG signal amplitude, changing in a predictable manner, and finally (e) there was tuning in which elbow muscles were activated earlier for goal-directed arm movements in the left area of the work-space.
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Smith, Nigel Anthony. "Oxygen consumption and muscle activation patterns during constant load exercise." Thesis, Queensland University of Technology, 2000. https://eprints.qut.edu.au/36769/1/36769_Digitised%20Thesis.pdf.
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The collective purpose of these two studies was to determine a link between the V02 slow component and the muscle activation patterns that occur during cycling. Six,
male subjects performed an incremental cycle ergometer exercise test to determine asub-TvENT (i.e. 80% of TvENT) and supra-TvENT (TvENT + 0.75*(V02 max - TvENT)
work load. These two constant work loads were subsequently performed on either three or four occasions for 8 mins each, with V02 captured on a breath-by-breath basis
for every test, and EMO of eight major leg muscles collected on one occasion. EMG was collected for the first 10 s of every 30 s period, except for the very first 10 s
period. The V02 data was interpolated, time aligned, averaged and smoothed for both intensities. Three models were then fitted to the V02 data to determine the kinetics
responses. One of these models was mono-exponential, while the other two were biexponential. A second time delay parameter was the only difference between the two
bi-exponential models. An F-test was used to determine significance between the biexponential models using the residual sum of squares term for each model. EMO was
integrated to obtain one value for each 10 s period, per muscle. The EMG data was analysed by a two-way repeated measures ANOV A. A correlation was also used to
determine significance between V02 and IEMG. The V02 data during the sub-TvENT intensity was best described by a mono-exponential response. In contrast, during
supra-TvENT exercise the two bi-exponential models best described the V02 data. The resultant F-test revealed no significant difference between the two models and
therefore demonstrated that the slow component was not delayed relative to the onset of the primary component. Furthermore, only two parameters were deemed to be
significantly different based upon the two models. This is in contrast to other findings. The EMG data, for most muscles, appeared to follow the same pattern as V02 during
both intensities of exercise. On most occasions, the correlation coefficient demonstrated significance. Although some muscles demonstrated the same relative increase in IEMO based upon increases in intensity and duration, it cannot be assumed that these muscles increase their contribution to V02 in a similar fashion. Larger muscles with a higher percentage of type II muscle fibres would have a larger increase in V02 over the same increase in intensity.
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Kelson, Denean M. "Muscle Activation Patterns and Chronic Neck-Shoulder Pain in Computer Work." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/83759.
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Prolonged computer work is associated with high rates of neck and shoulder pain symptoms, and as computers have become increasingly more common, it is becoming critical that we develop sustainable interventions targeting this issue. Static muscle contractions for prolonged periods often occur in the neck/shoulder during computer work and may underlie muscle pain development in spite of rather low relative muscle load levels. Causal mechanisms may include a stereotypical recruitment of low threshold motor units (activating type I muscle fibers), characterized by a lack of temporal as well as spatial variation in motor unit recruitment. Based on this theory, although studies have postulated that individuals with chronic neck-shoulder pain will show less variation in muscle activity compared to healthy individuals when engaged in repetitive/monotonous work, this has seldom been verified in empirical studies of actual computer work.
Studies have rarely addressed temporal patterns in muscle activation, even though there is a consensus that temporal activation patterns are important for understanding fatigue and maybe even risks of subsequent musculoskeletal disorders. This study applied exposure variation analysis (EVA) to study differences in temporal patterns of trapezius muscle activity as individuals with and without pain performed computer work. The aims of this study were to: Assess the reliability of EVA to measure variation in trapezius muscle activity in healthy individuals during the performance of computer work; Determine the extent to which healthy subjects differ from those with chronic pain in trapezius muscle activity patterns during computer work, measured using EVA.
Thirteen touch-typing, right-handed participants were recruited in this study (8 healthy; 5 chronic pain). The participants were asked to complete three 10-minute computer tasks (TYPE, CLICK and FORM) in two pacing conditions (self-paced, control-paced), with the healthy group completing two sessions and the pain group completing one. Activation of the upper trapezius muscle was measured using surface electromyography (EMG). EMG data were organized into 5x5 EVA matrices with five amplitude classes (0-6.67, 6.67-20, 20-46.67, 46.67-100, >100% Reference Voluntary Exertion) and five duration classes (0-
1, 1-3, 3-7, 7-15, >15 seconds). EVA marginal distributions (along both amplitude and duration classes) for each EVA class, as well as summary measures (mean and SD) of the marginal sums along each axis were computed. Finally, “resultant” mean and SD across all EVA cells were computed. The reliability in
EVA indices was estimated using intra-class correlation coefficients (ICC), coefficient of variation (CV) and standard error of measurement (SEM), computed from repeated measurements of healthy individuals (aim 1), and EVA indices were compared between groups (aim 2).
Reliability of EVA amplitude marginal sums ranged from moderate to high in the self-paced condition and low to moderate in the control-paced condition. The duration marginal sums were moderate in the self-paced condition and moderate to high in the control-paced condition. The summary measures (means and
SDs) were moderate to high in both the self-paced and control-paced condition. Group comparisons revealed that individuals with chronic pain spent longer durations of work time in higher EVA duration categories, exhibited larger means along the amplitude, duration and in the resultant, and higher EVA SD
in the amplitude and duration axes as compared to the healthy group.
To our knowledge, this is the first study to report on the reliability of EVA applied specifically to computer work. Furthermore, EVA was used to assess differences in muscle activation patterns as individuals with and without chronic pain engaged in computer work. Individuals in the pain group seemed to exhibit prolonged sustained activation of the trapezius muscle to a significantly greater extent than controls, even though they did not experience pain during the performance of the computer tasks (as obtained through self-reports). Thus, these altered muscle recruitment patterns observed in the pain subjects, even in the absence of task-based pain/discomfort, are suggestive of chronic motor control changes occurring in adaptation to pain, and may have implications for the etiology of neck and upper-limb musculoskeletal disorders.Master of Science
This study aims to assess the reliability of exposure variation analysis (EVA) to measure variation in trapezius muscle activity in healthy individuals during the performance of computer work, and to determine the extent to which healthy subjects differ from those with chronic pain in trapezius muscle activity patterns during computer work, measured using EVA. Muscle activation was recorded for eight healthy individual and five suffering from chronic neck-shoulder pain. The data were then categorized into amplitude and continuous time categories, and summary measures of resulting distributions were calculated. These measures were used to assess the reliability of participant responses to computer work of healthy individuals, as well as quantify differences between those with and without chronic pain. We found that individuals with pain activated their neck-shoulder muscles for longer continuous durations than healthy individuals, thus showing an inability to relax their muscles when performing work.
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Sohn, Mark Hongchul. "Assessing functional stability of predicted muscle activation patterns for postural control using a neuromechanical model of the cat hindlimb." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42869.
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The underlying principles of how the nervous system selects specific muscle activation pattern, among many that produce the same movement, remain unknown. Experimental studies suggest that the nervous system may use fixed groups of muscles, referred to as muscle synergies, to produce functional motor outputs relevant to the task. In contrast, predictions from biomechanical models suggest that minimizing muscular effort may be the criteria how a muscle coordination pattern is organized for muscle synergies. However, both experimental and modeling evidence shows that stability, as well as energetic efficiency, also needs to be considered.
Based on the hypothesis that the nervous system uses functionally stable muscle activation pattern for a muscle synergy, we investigated the stability of muscle patterns using a neuromechanical model of the cat hindlimb. Five unique muscle patterns that generate each of the five experimentally-identified muscle synergy force vectors at the endpoint were found using a minimum-effort criterion. We subjected the model to various perturbed conditions and evaluated functional stability of each of the five minimum-effort muscle synergies using a set of empirical criteria derived from experimental observations.
Results show that minimum-effort muscle synergies can be functionally stable or unstable, suggesting that minimum-effort criterion is not always sufficient to predict physiologically relevant postural muscle synergies. Also, linearized system characteristics can robustly predict the behavior exhibited by fully dynamic and nonlinear biomechanical simulations. We conclude that functional stability, which assesses stability of a biomechanical system in a physiological context, must be considered when choosing a muscle activation pattern for a given motor task.
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Lockhart, Daniel Bruce. "Prediction of Muscle Activation Patterns During Postural Control Using a Feedback Control Model." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7280.
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Neural mechanisms determining temporal muscle activity patterns during postural control are not well understood. We hypothesize that a feedback control mechanism can predict both temporal extensor muscle EMG and CoM kinematics (acceleration, velocity, and displacement) during postural perturbations before and following peripheral neuropathy to group I afferents induced by pyridoxine intoxication. We introduce a feedback model for analyzing temporal EMG patterns that decomposes recorded electromyogram (EMG) signals into the sum of three center of mass (CoM) feedback components. EMG and CoM kinematics during postural responses due to support surface translations were measured before and 14 days after somatosensory loss in cats. We successfully predicted EMG before and after peripheral neuropathy by modeling a standing cat as an inverted pendulum and decomposing temporal EMG patterns using a simulation with time delayed feedback loop of CoM kinematics. This model accounts for over 60% of the total temporal variability of recorded extensor EMG patterns. Feedback gains for acceleration, velocity and position necessary to predict EMGs before and after sensory loss were different. For intact animals, more that 90% of the initial burst of EMG were due to CoM acceleration feedback, while later portions were due entirely to velocity and position feedback. After peripheral neuropathy, the initial burst was absent and the acceleration gain was significantly reduced when compared to the acceleration gain of intact animals for extensor muscles (p lt 0.05). By successfully decomposing EMG into three kinematic gains, a quantitative comparison of temporal EMG patterns before and after peripheral neuropathy is possible. The reduction of acceleration gain in sensory loss cats suggests that group I afferents provide necessary information that is used as acceleration feedback.
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Stone, T. A. "Characteristics of muscle activation patterns at the ankle in stroke patients during walking." Thesis, Bournemouth University, 2006. http://eprints.bournemouth.ac.uk/10537/.
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Stroke causes impairment of the sensory and motor systems; this can lead to difficulties in walking and participation in society. For effective rehabilitation it is important to measure the essential characteristics of impairment and associate these with the nature of disability. Efficient gait requires a complex interplay of muscles. Surface electromyography(sEMG) can be used to measure muscle activity and to observe disruption to this interplay after stroke. Yet, classification of this disruption in stroke patients has not been achieved. It is hypothesised that features identified from the sEMG signal can be used to classify underlying impairments. A clinically viable gait analysis system has been developed, integrating an in-house wireless sEMG system synchronised with bilateral video and inertial orientation sensors. Signal processing techniques have been extended and implemented, appropriate for use with sEMG. These techniques have focussed on frequency domain features using wavelet analysis and muscle activation patterns using principal component analysis. The system has been used to measure gait from stroke patients and un-impaired subjects. Characteristic patterns of activity from the ankle musculature were defined using principal component analysis of the linear envelope. Patients with common patterns of tibialis anterior activity did not necessarily share common patterns of gastrocnemius or soleus activity. Patients with similar linear envelope patterns did not always present with the same kinematic profiles. The relationship between observable impairments, kinematics and sEMG is seen to be complex and there is therefore a need for a multidimensional view of gait data in relation to stroke impairment. The analysis of instantaneous mean frequency and time-frequency has revealed additional periods of activity not obvious in the linear or raw signal representation. Furthermore, characteristic calf activity was identified that may relate to abnormal reflex activity. This has provided additional information with which to group characteristic muscle activity. An evaluation of the co-activation of gastrocnemius and tibialis anterior muscles using a sub-band filtering technique revealed three groups; those with distinct co-activation, those with little co-activation and those with continuous activity in the antagonistic pair across the stride. Signal features have been identified in sEMG recordings from stroke patients whilst walking extending current signal processing techniques. Common features of the sEMG and movement have been grouped creating a decision matrix. These results have contributed to the field of clinical measurement and diagnosis because interpretation of this decision matrix is related to underlying impairment. This has provided a framework from which subsequent studies can classify characteristic patterns of impairment within the stroke population; and thus assist in the provision of rehabilitative interventions.
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Sohn, Mark Hongchul. "A computational framework to quantify neuromechanical constraints in selecting functional muscle activation patterns." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53591.
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Understanding possible variations in muscle activation patterns and its functional implications to movement control is crucial for rehabilitation. Inter-/intra-subject variability is often observed in muscle activity used for performing the same task in both healthy and impaired individuals. However, the extent to which muscle activation patterns can vary under specific neuromuscular conditions and differ in function are still not well understood. Current musculoskeletal modeling approaches using optimization techniques to identify a unique solution cannot adequately address such questions. Here I developed a novel computational framework using detailed musculoskeletal model to reveal the latitude the nervous system has in selecting muscle activation patterns for a given task regarding neuromechanical constraints. I focused on isometric hindlimb endpoint force generation task relevant to balance behavior in cats. By identifying the explicit bounds on activation of individual muscles defined by biomechanical constraints, I demonstrate ample range of feasible activation patterns that account for experimental variability. By investigating the possible neuromechanical bases of using the same muscle activation pattern across tasks, I demonstrate that demand for generalization can affect the selection of muscle activation pattern. By characterizing the landscape of the solution space with respect to multiple functional properties, I demonstrate a possible trade-off between effort and stability. This framework is a useful tool for understanding principles underlying functional or impaired movements. We may gain valuable insights to developing effective rehabilitation strategies and biologically-inspired control principles for robots.
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Koenig, Alexander C. "Simulation of agonist and antagonist muscle activation patterns in bidirectional postural perturbation in cats." Thesis, Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11576.
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We studied the effects of varying perturbation magnitude and direction on the postural control process of the central nervous system (CNS) caused by perturbation, before and after sensory loss. The electromyogram (EMG) response to a postural perturbation can be composed by a weighted sum of the center of mass (CoM) kinematics. We extended an existing CoM feedback model which predicted EMG of one muscle for unidirectional perturbations; we used recorded data of bidirectional perturbations, which caused muscle activity in anterior as well as posterior muscles. Modeling the CNS as two delayed feedback controllers, we reconstructed the EMGs of two antagonistic muscles simultaneously that were recorded during postural perturbation experiments on cats. Minimizing the error between predicted and recorded EMG and CoM kinematics, we were able to identify controller gains that would result in the best prediction of the recorded EMGs.
We hypothesized that the weights on the CoM kinematics remained constant independent of variations in perturbation magnitude or reversed perturbation direction. We applied our model to data from bidirectional perturbations with varying magnitude, with which the cats were perturbed for a short time in one direction and a longer time in the opposite direction.
The gains showed small variation for EMG predictions following long perturbations; however, the prediction of EMG following the initial displacement resulted in large gain variations. We showed that these variations were caused by our optimization methods, which was not able to consistently identify controller gains for short initial movements. Using the weights identified for unidirectional perturbations, we were able to predict muscle activity for both directions with the same gains. This suggests that the weights of the CoM kinematics for each muscle did not change for varying perturbation magnitude. We conclude that varying EMG shapes were induced solely by the variation of the CoM kinematics.
We repeated the investigations on data that was recorded from cats suffering from sensory loss and found reduced CoM acceleration feedback.
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Poon, Wai Ming, and n/a. "Gait analysis of lumbar muscle activation patterns during constant speed locomotion using Surface Electromyography." RMIT University. Electrical and Computer System Engineering, 2009. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20090713.115553.
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This thesis reports research on analysis of the variance of surface electromyogram (sEMG) for healthy participants and people suffering with Lower Back Pain (LBP) when they are walking and running. SEMG signal recorded when the participants were walking and running on a treadmill. The strength and duration of the muscle activity for each heel strike were the features. The results indicate that there was no significant difference in the variance and in the change of variance over time of the amplitude between the two groups when the participants were walking. However when the participants were running, there was a significant difference in the two cohorts. While there was an increase in the total variance over the duration of the exercise for both the groups, the increase in variance of the LBP group was much greater (order of ten times) compared with the participants with healthy backs. The difference between the two groups was also very significant when observing the change of variance over the duration of the exercise. From these results, it is suggested that variance of sEMG of the muscles of the lower back, recorded when the participants are running, can be used to identify LBP patients.
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Macrum, Elisabeth Corliss Padua Darin A. "The relationship between dorsiflexion range of motion and lower extremity movement patterns and muscle activation." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2008. http://dc.lib.unc.edu/u?/etd,1882.
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Thesis (M.A.)--University of North Carolina at Chapel Hill, 2008.Title from electronic title page (viewed Dec. 11, 2008). "... in partial fulfillment of the requirements for the degree of Master of Art in the Department of Exercise & Sport Science in the College of Arts & Sciences." Discipline: Exercise and Sports Science; Department/School: Exercise and Sport Science.
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Crook, Tracy. "The functional anatomy of equine hind limb muscles and their activation patterns during different locomotor tasks." Thesis, Royal Veterinary College (University of London), 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.572457.
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Bigham, Heather Jean. "Sex Differences in Lower Limb Muscle Activation Patterns in Participants with Knee Osteoarthritis and Healthy Controls." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32377.
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Muscular stabilisation strategies during activities of daily living alter in the presence of knee osteoarthritis (OA). By examining neuromuscular adaptations using our weight-bearing target match protocol, the main objective of this research is to establish sex differences in adaptations of neuromuscular control that are associated with older males and females with and without OA. 66 participants completed the protocol while EMG, ground reaction forces (GRF), and kinematics were recorded. Muscle activation patterns were presented in polar plots with an EMG vector representing normalised muscle activation in twelve directions, each representing a GRF vector scaled to 30% maximal effort. Asymmetry about the polar plot (activation occurring in one direction more than another) was determined and specificity index (SI) and mean direction of activation were calculated when appropriate.
Healthy females demonstrated greater rectus femoris (RF) mean muscle magnitude (XEMG) (p=0.067) and less biceps femoris (BF) XEMG than healthy males (p=0.084) and females with OA (p=0.041), and males and females with OA demonstrated greater RF XEMG than healthy controls of the same sex (p=0.016, 0.072, respectively). Females with OA had significantly greater medial gastrocnemius XEMG than healthy females (p=0.031) and males with OA (p=0.020). Females with OA have less specificity in all muscles compared to males with OA and OA participants generally had less specificity compared to healthy controls of the same sex. Healthy males had the largest SI for lateral gastrocnemius with an asymmetrical activation pattern contrasting the more symmetrical activation pattern of all other groups.
In conclusion, we suggest OA-affected adults and healthy females use a quadriceps dominant strategy to stabilise the joint, and that this strategy may be a compensatory mechanism for reduced quadriceps function. We suggest RF, BF, MG, and LG should be targeted for prophylactic intervention as they displayed altered activation strategies in participants with OA and healthy females.
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Maneshi, Anali. "The effects of the menstrual cycle on muscle activation patterns and fuel utilization in cold exposure." Thesis, University of Ottawa (Canada), 2009. http://hdl.handle.net/10393/28413.
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Cold-induced shivering is characterized by two distinct muscle contraction patterns: continuous low-intensity shivering [at ∼1 to 5% of maximal voluntary contraction (MVC)] and bursts of high-intensity shivering (at 10 to 35% MVC) (Meigal, 2002, Haman et al., 2004). In this context, Haman et al. (2004) showed that carbohydrate (CHO) oxidation rate is directly related to burst shivering rate which increases the proportional recruitment of glycolitic type II fibers. Because most of these studies have been carried out in men, little is still know on the effects of hormonal fluctuations during the menstrual cycle on the dual shivering pattern and energy metabolism in women.
Therefore, the purpose of this study was to quantify differences in muscle recruitment pattern and fuel selection in two phases of the menstrual cycle. Muscle recruitment in eight muscles and whole body fuel selection were monitored in women exposed to 120 min of cold exposure (5°C liquid-perfusion suit) during FP and LP. Results show that there is no difference in the onset of shivering, shivering intensity, burst duration and burst shivering rate between LP and FP during steady state shivering (in last 15 min). Similarly, during steady state shivering (T=105-120 min), absolute rates and relative contributions of metabolic fuels to total heat production did not differ between FP and LP. We conclude that hormonal fluctuations during the menstrual cycle do not affect muscle recruitment patterns or substrate utilization in the cold. Whether this important difference in fuel selection modifies muscle shivering activity and/or confers a survival advantage remains to be established.
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Welch, Torrence David Jesse. "A feedback model for the evaluation of the adaptive changes to temporal muscle activation patterns following postural disturbance." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/29674.
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Thesis (Ph.D)--Biomedical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Ting, Lena; Committee Member: Chang, Young-Hui; Committee Member: Nichols, T. Richard; Committee Member: Schumacher, Eric; Committee Member: Thoroughman, Kurt. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Zink, Cody J. "Lower Extremity Muscle Activation Patterns During the Propulsion Phase of a Single Limb Hop Task in Patients Following ACL Reconstruction and Healthy Controls." University of Toledo / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=toledo152546398384202.
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Alamro, Raid. "Trunk muscle activation patterns during walking with robotic exoskeletons in people with high thoracic motor-complete spinal cord injury." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/61270.
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Background: Maintaining postural stability during sitting or standing depends critically on motor function in the trunk muscles. Trunk muscle function is typically assumed to be poor or absent in people with a complete spinal cord injury (SCI) at or above the thoracic level. However, recent studies have revealed sparing of trunk muscle function in people with high-thoracic motor-complete SCI, opening up the possibility for training techniques to improve their function. The Lokomat and Ekso are used in gait rehabilitation for people with SCI, but it remains unknown how much they engage those trunk muscles that are normally activated during walking. These devices provide gait training in different methods. In Lokomat, the trunk is rigidly and passively supported by a body weight support harness, which could imply lesser recruitment of postural muscles. In contrast, the Ekso requires continuous weight shifting from one limb to the other to trigger steps, which could lead to better postural muscle activation.
Objective: To compare trunk muscle activation patterns during Ekso- vs Lokomat-assisted walking in people with high-thoracic motor-complete SCI.
Methods: 8 individual with C7-T4 chronic motor-complete SCI were recruited. Subjects performed 3 walking conditions (at matched speeds): Lokomat-assisted walking (Loko-TM), Ekso-assisted walking on treadmill (Ekso-TM), and Ekso-assisted walking overground (Ekso-OG). Surface electromyography (EMG) signals were recorded bilaterally from rectus abdominis (RA), external oblique (EO), and erector spinae (ES) and normalized to (attempted) maximum voluntary contraction (MVC). EMG amplitudes were compared during baseline (lying supine) (BAS) and across the 3 walking conditions. EMG onset and total activity times were compared across the 3 walking conditions.
Results: Trunk EMG amplitudes were significantly higher in Ekso-TM compared to both Loko-TM and BAS. RA and ES amplitudes were not different during Loko-TM walking compared to BAS. When Ekso-OG was compared to Ekso-TM, only ES amplitude was significantly different. Onset and total activity times were not significantly different across the walking conditions
Conclusion: Ekso-assisted walking was better in activating trunk muscles than the Lokomat-assisted walking. These results suggest that Ekso could possibly be used to train trunk strength and improve sitting postural control in people with high-thoracic motor-complete SCI.Education, Faculty of
Kinesiology, School of
Graduate
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Burns, Jack. "Does training with PowerCranks affect economy of motion, cycling efficiency, oxygen uptake and muscle activation patterns in trained cyclists?" Connect to thesis, 2008. http://adt.ecu.edu.au/adt-public/adt-ECU2008.0017.html.
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Zajdman, Olivia. "An Investigation into the Sex Differences Between Older Adults with Osteoarthritis in Kinetics, Kinematics, and Muscle Activation Patterns During Squatting." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/35654.
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INTRODUCTION: Altered neuromuscular control and knee joint instability are commonly observed in populations with knee osteoarthritis (OA). Since knee OA is more prevalent in females, sex-related differences in muscle activation and movement strategies during activities of daily living (ADL) are theorized to be a contributing factor to the increased prevalence in females. PURPOSE: The aims of this thesis were: 1) identify sex differences in joint dynamics and muscle activation patterns in older adults with knee OA and healthy older adults; and 2) investigate whether differences in co-activation and dynamic knee joint stiffness exist between sexes in an OA and healthy populations. For both aims, squatting tasks were evaluated because it is a common and critical component in ADLs. METHODS: Thirty healthy individuals (15 females) and thirty individuals with knee OA (15 female) performed three two-legged squats at a self-selected pace on two force platforms. Hip, knee, and ankle sagittal and frontal plane joint angles, moments and powers were calculated and electromyography (EMG) of eight muscles crossing the knee joint was recorded for the test (OA affected or dominant) limb. Maximum voluntary isometric contractions were used to normalize the EMG data. Co-activation indices for six antagonist muscle pairings and dynamic knee joint stiffness (DKJS) were calculated for the acceleration and deceleration phases of squat descent and ascent. Two-way ANOVAs (Sex X OA status) were used to characterize differences in muscle activation patterns and movement strategies. RESULTS: For aim 1, decreased hip, knee and ankle sagittal plane range of motion was identified in the OA participants, with females showing the greater deficits compared to the males. Males with OA implemented a hip dominant strategy by increasing hip joint moments and decreasing knee joint moments compared to the females. Indifferent of joint status, females performed the squat with more hip adduction compared to males. Females with OA demonstrated greater hip adduction and knee valgus angles throughout the squat, contributing to the decrease in the frontal plane range of motion. Additionally, hip joint power was lower in all female participants compared to males while knee joint power was lower in the OA participants. For aim 2, females with OA, and to lesser extent males with OA had greater DKJS around peak knee flexion compared to the healthy participants. Co-activation indices revealed sex differences in neuromuscular control: Females with knee osteoarthritis had higher muscle activation magnitude and co-activation of antagonistic muscles, whereas the males used a more selective increase in hamstring co-activation and more balanced quadriceps-hamstring recruitment. CONCLUSION: Two-legged squats were able to detect sex and OA related functional deficits at the knee and adjacent hip and ankle joints. OA had a greater effect on the movement and neuromuscular control in females than males and the squat identified specific deficiencies that can be targeted for rehabilitation.
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Clarke, Krista L. "An electromyographic comparison of trunk muscle activation amplitudes and patterns associated with a lower abdominal exercise progression in healthy normal subjects." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ57217.pdf.
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Rutherford, Derek. "Factors affecting knee joint muscle activation patterns during gait in individuals with knee osteoarthritis." Thesis, 2011. http://hdl.handle.net/10222/14410.
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Knee osteoarthritis (OA) is a progressive disease and a leading cause of morbidity in older adults, resulting in severe mobility limitations. While the osteoligamentous and neuromuscular systems are altered in knee OA, little data is available to illustrate an association among these systems. The objective of this dissertation was to improve our understanding of how muscle activation patterns during gait are altered across the knee OA severity spectrum and to examine how factors related to the OA process are associated with these alterations. Three independent but related studies were conducted.
Muscle activation of the medial and lateral orientations of the gastrocnemii, quadriceps and hamstrings were recorded during gait using surface electromyography for all three studies. Key activation features were identified using principal component analysis. First, participants selected from a large group (n=272) of individuals classified as asymptomatic, ii) moderate ii) severe knee OA were matched for walking velocity. Significant amplitude and temporal activation characteristics were found, supporting that differences among OA severities exist and were not the result of walking velocity only. Secondly, individuals with moderate OA were sub-grouped based on structural severity determined using Kellgren-Lawrence radiographic scores (II-IV) and were compared to a velocity-matched asymptomatic group. Medial gastrocnemius, lateral hamstring and quadriceps amplitudes and temporal patterns were significantly altered by structural severity where significant activation imbalances between the lateral:medial gastrocnemii and hamstrings were found with greater structural impairment (score>II). Thirdly, individuals with moderate OA were prospectively evaluated and divided into knee effusion and no effusion groups, based on a positive bulge test. A significantly higher knee flexion angle during mid-stance, higher quadriceps amplitudes and prolonged hamstrings amplitudes were found when effusion was found.
These studies showed that muscle activation patterns during walking were related to i) OA presence and severity based on functional, symptoms and radiographic evidence, ii) structural severity and iii) knee joint effusion. These findings improve our understanding of the interrelationships between alterations in joint structure and function associated with knee OA and muscle activation patterns during gait. These data can contribute to the development of gait-based metrics that can facilitate knee OA diagnosis and monitor progression.
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mien, Huang-hsiang, and 黃湘棉. "The Relationship between Muscle Activation Pattern and Functional Impairment during Trunk Flexion and Recovery in Patients with Low Back Pain." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/71591190571234145666.
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碩士國立體育學院
運動傷害防護研究所
92
Background and purpose: Previous studies revealed that deviated muscle activation pattern（MAP）, such as various activation amplitudes of erector spinae, were existed in patients with low back pain（LBP）during end of saggital trunk flexion. In addition to amplitudes, the timing control of muscle activation also takes an important part in the motor control of muscles. This study compared the activation patterns in terms of activation and relaxation timing of selected muscles between healthy and chronic nonspecific LBP patients. For further investigating the meanings of deviated MAP, functional impairments and pain of LBP patients were also documented. Method: Six healthy （age=36.44±2.29y/o, 33.17~39.75y/o） and seven LBP patients（age＝41.10±5.73y/o, 33~48.25y/o）were recruited. The subjects performed the trunk flexion to 70 degree and recovery movement. The surface electrodes were placed over muscles around trunk and pelvis to detect the changes of action potential as muscle timing control. The accelerometers were placed over T4, S2 and lateral-middle point of left thigh used to perform the changes of angle in trunk and hip joints. The modified Oswestry disability questionnaires and visual analog scales were been tested in each group to collect the disability index and pain intensity. Result: There were no significant differences of onset and offset time and its related trunk angle in all muscles between healthy and LBP group. During end of recovery phase, the offset time of erector spinae and hamstring muscles in LBP were both 400ms less than healthy group. The right gluteal maximus was significantly related to functional impairments（r=0.768, p<0.05）and right hamstring muscles was significantly related to pain degree（r=-0.826, p<0.05）in LBP group. Conclusion: This study investigated the parameters of the muscle activation pattern as time and its trunk angle. The data showed that there were no general deviated muscle activation patterns as timing existed in LBP patients. Then the meaningful correlation between MAP and functional impairments and pain degree in LBP group were not proved. Therefore we suggested the neuromuscular function of erector spinae and hamstring muscles should be further investigated.
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Wu, Yu-Hsuan, and 吳昱璇. "A Comparison of Posterior Muscle Chain Activation Pattern during Uphill Walking in Adults With and Without Chronic Low Back Pain." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/91231734641381595875.
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碩士高雄醫學大學
物理治療學系碩士班
105
Background and Purpose: Chronic low back pain(CLBP) is a common musculoskeletal disorders .Alterations in posterior muscle chain activation pattern may due to pain, including muscles amplitude、onset time and activation order. The purpose of this study was to investigate posterior muscle chain activation pattern during uphill walking on a treadmill in adults with and without chronic low back pain . Methods: Eighteen patients with CLBP and 18 healthy individuals walked on a treadmill at self-selected speed in four grades: 0%、5%、10% and 15% slope. Electromyography data of the latissimus dorsi , erector spinae, gluteus maximus, and biceps femoris were collected during walking using a surface electromyograph. Muscles activation order ,onset time, and amplitude were recorded in every trial. Results: There was no a consistent order of muscle activation between both groups in the investigated muscles(erector spinae, gluteus maximus, and biceps femoris; latissimus dorsi ,erector spinae and gluteus maximus) in this study. Although there was no significant difference in the onset times, amplitude for all investigated muscles between the two groups, there was a significant difference between the two groups for biceps femoris amplitude on 10% slope. Conclusions: A consistent order of muscle activation was not found in both healthy and CLBP subjects while walking on level and slopes. Further research needs to investigate relationship between the kinematics of the trunk and lower extremity and the muscle activation pattern.
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Huang, Yi-Ming, and 黃奕銘. "The effect of agonist muscle fatigue in EMG activation pattern and the error of force generation while performing fast and slow isometric dorsiflexion." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/15707267570231102622.
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碩士國立體育學院
教練研究所
92
In sports, we often need to overcome muscle fatigue to maintain the performance interact by agonist and antagonist muscle. It is important to solve the poor control of agonist-antagonist activity muscle after fatigue. The purposes of this study are to evaluate the effect of agonist muscle fatigue on the error of force control and investigate the change of ago-ant muscle relationship. Ten healthy subjects were recruited. The subject was instructed to perform fast and slow isometric ankle dorsiflexion to a target force level of 40% MVC. The MVC force, error of force generation, and EMG of tibialis anterior and soleus were recorded before and after voluntary isometric fatigue. The results revealed that following fatigue, the MVC of dorsiflexion decreased significantly (p<.0001). The error of force generation increased in both fast and slow contractions after fatigue, wherein, the amount of increasing is larger in fast contractions. The co-contraction time of EMG increased (p<.05) in slow movement but not in fast one. EMG activities of TA and SOL muscles increased after muscle fatigue at both speeds (p<.05). No triphasic EMG was found in our data. In conclusion, there was enough time in slow contractions to modify ago-ant control strategies which minimized the error of target setting. The increase of random error after fatigue could not be adjusted by ago-ant muscle control. In order to enhance performance in sports, coaches are suggested to re-educate ago-ant muscle control of fast movement after fatigue.
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Chao, Li-Feng, and 趙立峰. "Muscle Activation Patterns of Forearm during Driving a Power Wheelchair." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/63704072128157745449.
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碩士亞洲大學
創意商品設計學系
104
Power wheelchairs is available for cerebral palsy children to moving quickly reach the desired destination. Cerebral palsy children can not smooth control the wheelchair that due to the abnormal involuntary spasms and tension. The purpose of this study was used electromyographic (EMG) to assess the muscle activation patterns during driving the power wheelchair. We recruited a healthy individual in this evaluating examination. The evaluating examination were divided into a control group and the experimental group. As the control group, the subject was required to forward movement by controlling the wheelchair joystick; as the experimental group, the subject was required to backward movement, left turning, and right turning, respectively. The surface EMG was used to record the contraction of three right upper limbs muscles, including extensor carpi ulnaris (ECU), flexor carpi ulnaris (FCU), and flexor carpi radialis FCR). The results showed that the three right upper limb muscles profile a different activation patterns during driving a power wheelchair. The findings imply that the muscle sequence pattern can be used to profile the joystick control strategy in power wheelchairs.
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Chow, Amy. "Investigation of Hand Forces, Shoulder and Trunk Muscle Activation Patterns and EMG/force Ratios in Push and Pull Exertions." Thesis, 2010. http://hdl.handle.net/10012/5551.
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When designing work tasks, one goal should be to enable postures that maximize the force capabilities of the workers while minimizing the overall muscular demands; however, little is known regarding specific shoulder tissue loads during pushing and pulling. This study quantitatively evaluated the effects of direction (anterior-posterior pushing and pulling), handle height (100 cm and 150 cm), handle orientation (vertical and horizontal), included elbow angle (extended and flexed) as well as personal factors (gender, mass and stature) on hand force magnitudes, shoulder and L5/S1 joint moments, normalized mean muscle activation and electromyography (EMG)/force ratios during two-handed maximal push and pull exertions. Twelve female and twelve male volunteers performed maximal voluntary isometric contractions under 10 push and pull experimental conditions that emulated industrial tasks. Hand force magnitudes, kinematic data and bilateral EMG of seven superficial shoulder and trunk muscles were collected. Results showed that direction had the greatest influence on dependent measures. Push exertions produced the greatest forces while also reducing L5/S1 extensor moments, shoulder moments with the 150 cm height and overall muscular demands (p < 0.0001). The 100 cm handle height generated the greatest forces (p < 0.0001) and reduced muscular demands (p < 0.05), but were associated with greater sagittal plane moments (p < 0.05). Females generated, on average, 67% of male forces in addition to incurring greater muscular demands (p < 0.05). The flexed elbows condition in conjunction with pushing produced greater forces with reduced overall muscular demands (p < 0.0001). Furthermore, horizontal handle orientation caused greater resultant moments at all joints (p <. 0.05) The results have important ergonomics implications for evaluating, designing or modifying workstations, tasks or equipment towards improved task performance and the prevention of musculoskeletal injuries and associated health care costs.
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Dutto, Darren John. "Leg spring model related to muscle activation, force, and kinematic patterns during endurance running to voluntary exhaustion." Thesis, 1999. http://hdl.handle.net/1957/33158.
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Sidorkewicz, Natalie. "Lumbar Spine and Hip Kinematics and Muscle Activation Patterns during Coitus: A comparison of common coital positions." Thesis, 2013. http://hdl.handle.net/10012/7332.
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Qualitative studies investigating the sexual activity of people with low back pain found a substantial reduction in the frequency of coitus and have shown that pain during coitus due to mechanical factors (i.e., movements and postures) are the primary reason for this decreased frequency. However, a biomechanical analysis of coitus has never been done. The main objective of this study was to describe male and female lumbar spine and hip motion and muscle activation patterns during coitus and compare these motions and muscle activity across five common coital positions. Specifically, lumbar spine and hip motion in the sagittal plane and electromyography signal amplitudes of selected trunk, hip, and thigh muscles were described and compared. A secondary objective was to determine if simulated coitus could be used in place of real coitus for future coitus biomechanics research.
Ten healthy males (29.3 ± 6.9 years, 176.5 ± 8.6 centimeters, 84.9 ± 14.5 kilograms) and ten healthy females (29.8 ± 8.0 years, 164.9 ± 3.0 centimeters, 64.2 ± 7.2 kilograms) were included for analysis in this study. These couples had approximately 4.7 ± 3.9 years of sexual experience with each other. This study was a repeated-measures design, where the independent variables, coital position and condition, were varied five (i.e., QUADRUPED1, QUADRUPED2, MISSIONARY1, MISSIONARY2, and SIDELYING) and two (i.e., real and simulated) times, respectively. Recruited participants engaged in coitus in five pre-selected positions (presented in random order) for 20 seconds per position first in a simulated condition, and again in a real condition. Three-dimensional (3D) lumbar spine and hip kinematic data were continuously collected for the duration of each trial by optoelectronic and electromagnetic motion capture systems. Electromyography (EMG) signals were also continuously collected for the duration of each trial. The kinematic data and EMG signals were collected simultaneously for both participants. Five sexual positions were chosen for this study based on the findings of previous literature and a biomechanical rationale. QUADRUPED – rear-entry, female quadruped, male kneeling behind – had two variations; in QUADRUPED1 the female was supporting her upper body with her elbows and in QUADRUPED2 the female was supporting her upper body with her hands. MISSIONARY – front-entry, female supine, male prone on top – also had two variations; in MISSIONARY1 the female was not flexing her hips or knees and the male was supporting his upper body with his hands, but in MISSIONARY2, the female was flexing her hips and knees and the male was supporting his upper body with his elbows. SIDELYING – rear-entry, female side-lying on her left side, male side-lying behind – did not have any variations. To determine if each coital position had distinct spine and hip kinematic and muscle activation profiles, separate univariate general linear models (GLM) (factor: coital position = five levels, α=0.05) followed by Tukey’s honestly significant difference (HSD) post hoc analysis were used. To determine if simulated coitus was representative of real coitus across all spine and hip kinematic and muscle activation outcome variables, paired-sample t-tests (α=0.05) were performed on all outcome variables for the real condition and their respective simulated values.
In general, the coital positions studied showed that, for both males and females, coitus is mainly a flexion-extension movement of the lumbar spine and hips. Males used a greater range of their spine and hip motion in comparison to females. As expected, differences were found between coital positions for males and females and simulated coitus was not representative of real coitus, in particular the spine and hip kinematic profiles. The results found in this biomechanical analysis of common coital positions may be useful in a clinical context. It is recommended that during the acute stage of a low back injury resulting in flexion-, extension-, or motion-intolerance that coitus be avoided. If the LBP is a more chronic issue, particular common coital positions should be avoided. For the flexion-intolerant male patient, avoid SIDELYING and MISSIONARY2 as they were shown to require the most flexion. Both variations of QUADRUPED are the more spine-sparing of coital positions followed by, MISSIONARY1. Coaching the male patient on proper hip-hinging technique while thrusting – an easy technique to incorporate in both variations of QUADRUPED – will likely decrease spine movement and increase the spine-sparing quality of QUADRUPED. For the flexion-intolerant female patient, avoid both variations of MISSIONARY, especially with hip and knee flexion, as they were shown to elicit the most spine flexion. QUADRUPED2 and SIDELYING are the more spine-sparing coital positions, followed by QUADRUPED1. Subtle posture changes for a coital position should not be considered lightly; seemingly subtle differences in posture can change the spine kinematic profile significantly, resulting in a coital position that was considered spine-sparing becoming a position that should be avoided.
Thus, spine-sparing coitus appears to be possible for the flexion-, extension-, and motion-intolerant patient. Health care practitioners may recommend appropriate coital positions and coach coital movement patterns, such as speed control and hip-hinging. With respect to future research in the area of sex biomechanics, using simulated coitus in replace of real coitus is not justifiable according to the data of this study. However, including a simulated condition did prove beneficial for increasing the comfort level of the couples and allowing time to practice the experimental protocol. Future directions may address female-centric positions (e.g., ‘reverse missionary’ with male supine and female seated on top), and back-pained patients with and without an intervention (e.g., movement pattern coaching or aides, such as a lumbar support).
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Lee, Chien-Tzu, and 李建慈. "Activation Patterns of Diaphragm and Sternocleidomastoid Muscle during Threshold Loaded Breathing in Patients with Chronic Obstructive Pulmonary Disease." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/6vmsnw.
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碩士國立臺灣大學
物理治療學研究所
107
Background and purpose: Inspiratory muscle weakness has been shown in patients with chronic obstructive pulmonary disease (COPD), and inspiratory muscle training (IMT) is commonly applied to these patients. In healthy adults, the accessory inspiratory muscles would be recruited during IMT along with the primary inspiratory muscle. In patients with COPD, the activation patterns of diaphragm and accessory inspiratory muscles during threshold loaded breathing has not been investigated. Therefore, the purpose of this study was to exam diaphragm and sternocleidomastoid (SCM) activation using surface electromyography (EMG) during threshold loaded breathing with intensity of 30% and 50% maximal inspiratory pressure (PImax). Methods: This was a cross-sectional study. Patients with COPD diagnosis and a PImax lower than 60 cmH2O were recruited for the study. Surface EMG was used to measure the activation and the median frequency of diaphragm and SCM during quiet breathing, 30% and 50% PImax of threshold loaded breathing, and the first five minutes of recovery. Group-based trajectory modeling (GBTM) was used to identify diaphragm activation pattern across different breathing conditions. Generalized estimating equation (GEE) was then used to detect within and between differences of parameters among trajectory groups. Multiple regression analysis was used to identify factors associated with diaphragm and SCM activation. Significance p value was set at 0.05. Results: A total of 30 patients (25 males, 5 females) with COPD and a mean PImax of 46.7 (±13.3) cmH2O participated in this study. All patients demonstrated significant increases in diaphragm and SCM activation during 30% and 50% PImax of threshold loaded breathing compared to those of during quiet breathing (all p < 0.001), and the median frequency of diaphragm and SCM significantly decreased after both intensities of threshold loaded breathing (all p < 0.05). GBTM analysis identified two distinct patterns of diaphragm activation in response to threshold loaded breathing: low activation (n= 8) and high activation group (n= 22). Compared to high activation group, diaphragm activation and median frequency during quiet breathing and threshold loaded breathing were significantly lower in the low activation group (p < 0.05). Multiple regression analysis showed that the z-score of forced expiratory volume in one second to forced vital capacity ratio (FEV1/FVC z-score), diaphragm activation and median frequency during quiet breathing were associated with diaphragm activation during threshold loaded breathing, and only disease severity (z-score of forced expiratory volume in one second, FEV1 z-score) was associated with SCM activation during threshold loaded breathing. Conclusions: Diaphragm and SCM were activated to a greater extent in response to threshold loaded breathing in patients with COPD who had inspiratory muscle weakness. Diaphragm and SCM were fatigued after threshold loaded breathing. Furthermore, level of inspiratory muscle activation in response to threshold loaded breathing depended on their resting status. It is of clinical importance to find an optimal training strategy that would provide more benefit than harm when offering IMT for patients with COPD who have inspiratory muscle weakness.
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Freeman, Stephanie. "Can Altering Hip Joint Fluid Volume and Intra-Capsular Pressure Influence Muscle Activation Patterns? Neuromuscular Implications on Clinical Practice." Thesis, 2011. http://hdl.handle.net/10012/5913.
Full textAbstract:
Although the integrated relationship that exists between the lumbar spine and hip joints is frequently acknowledged in scientific journals and by medical professionals, specific functional and injury relationships, are speculative and have not been substantiated. Lumbar spine and hip dysfunctions are suspected to be associated with inhibition of the surrounding extensor musculature, particularly the gluteal muscles, and facilitation of the flexor musculature. This phenomenon has been observed in other joints following effusion and is often termed ‘arthrogenic inhibition’. Its apparent occurrence about the hip has never been validated. The primary objective of this thesis was to investigate whether arthrogenic inhibition occurred about the hip. If inhibition was found to exist, its relationship with volume vs pressure was investigated to determine if either of these factors were a more appropriate predictor of inhibition. Finally, compensatory motor patterns in response to apparent inhibition were of interest.
Participants were allocated to the following groups: 1) Control 2) Intervention I (magnetic resonance arthrogram) or 3) Intervention II (therapeutic arthrogram). Electromyography was collected on the rectus abdominis, erector spinae, gluteus maximus and semimenbranosis bilaterally during hip rehabilitation exercises prior to and following the intervention. Intra-capsular pressure was measured during the intervention.
The findings provided support for the presence of extensor-inhibition in the hip following infusion of intra-articular fluid with intra-capsular pressure being the most appropriate predictor of the magnitude of inhibition. Hip extensor inhibition appeared to be compensated for by lumbar spine extensors during the selected tasks. Arthrogenic inhibition should be considered in the clinical evaluation and management of patients with hip joint effusions and/or elevated intra-capsular pressure.
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Greyling, Miemie. "Pelvic biomechanics and muscle activation patterns during non-weighted squats in U/19 university-level rugby union players / Miemie Greyling." Thesis, 2013. http://hdl.handle.net/10394/11552.
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Hyperlordosis or anterior pelvic tilt is a common non-neutral spinal posture associated with weak core stability, low back pain and altered lumbopelvic muscle activation patterns. Yet the effects of altered lumbopelvic posture and core stability on muscle activation patterns have not been evaluated during a functional movement. The main purpose of this study was to determine the relationship between pelvic tilt, core stability and muscle activation patterns during non-weighted squats in U/19 university-level rugby union players. A total of 49 rugby union players participated in this study. Pelvic tilt (dominant side) was measured from a digital photo with clear reflector markers on the anterior superior iliac spine (ASIS) and posterior superior iliac spine (PSIS) using the Kinovea video analysis software programme (version 0.8.15). Flexibility of the hamstrings, hip flexors and knee extensors was assessed with goniometry. Core stability was assessed using the pressure biofeedback unit and muscle onset times during the ascent phase of non-weighted squats. The onset times of the transverse abdominis (TrA), erector spinae (ES), gluteus maximus (GM) and biceps femoris (BF) muscles were measured using electromyography (EMG). Players were then grouped according to pelvic tilt (anterior and neutral) and by playing position (forwards and backs). The between group differences were evaluated for the abovementioned variables using p-value (statistical significance) and d-value (practical significance) measures. Muscle activation patterns and firing order were determined using descriptive statistics.
The mean pelvic tilt of all participants (N=49) was an anterior tilt of 15.35°. When grouped by pelvic tilt, the anterior tilt group showed a mean pelvic tilt of 17.83° (n=27) and the neutral pelvic tilt group showed a mean pelvic tilt of 11.75° (n=22). Despite the differences in pelvic tilt, there was no significant difference in flexibility between the groups. Another controversial result is that the anterior tilt group showed practical significantly better core stability (d=0.54) than the neutral tilt group (46.93° vs 56.3°).
During the double leg squat the muscle activation patterns were consistent between the groups. TrA activated first, followed by ES. Thereafter, the BF muscle activated, followed by the GM. The first place activation of TrA is consistent with the literature stating that the deep abdominal stabilisers of individuals with good core stability activate before the movement is initiated. The early onset of muscle activity of ES points to a focus on back extension during the ascent of the squat. Because the pelvic tilt was measured during static standing only, it is unclear whether the players in the neutral tilt group were able to hold the neutral pelvic tilt posture throughout the movement. Research has shown that there is an increased focus on trunk extension during the ascent phase of the squat which is not present during the descent. Future research should focus on assessing the pelvic tilt at the beginning of the ascent phase of the squat to ensure accurate results.
The delay in GM activation during the ascent of the squat is concerning. GM acts as a lumbopelvic stabilizer, and its slow activation points to a decrease in lumbopelvic stability. This is very important in weight training, because weight training increases the strain on the lumbar spinal structures, which decreases performance and increases the risk of injury.MSc (Biokinetics), North-West University, Potchefstroom Campus, 2014
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Meng-Zhe, Zhao, and 趙孟哲. "The kicking leg muscle’s EMG activation patterns during kicking towards different objects in penalty kick by using inside kick." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/38680230847934514410.
Full textAbstract:
碩士國立臺灣師範大學
體育學系
103
In football, the most common way of shooting is by foot. Otherwise, the way of shooting can be divided into two patterns, which are full step kick and inside kick. As penalty kick always determinates the outcome of a game, Thus, how to raise the success rate of goal becomes an important issue. Therefore, most of the elite football players shoot by inside kick and aim the four corners of the goal, Even though the speed of the ball is not very fast, the player still can field the goal, which is hard for goal keeper to safe. But sometimes the players may miss the chance of fielding the goal, because of their muscle contract too excessive. The subjects of this study were eight colleage UFA 1 division players.The mark trajectories of body motion were collected by the VICON Motion Capture System(250Hz). Using Visaul 3D software to calculate the kinematic data.In the meanwhile, collecting the EMG data by Noraxon wireless EMG system(1500Hz)and also use HiSpec 4 high-speed video camara(500Hz) to record and calculate the data by MyoReserch XP Master Edition software. All the parameters were tested by Friedman two-way analysis of variance nonparametric statistical test by SPSS20.0, the significant level as α=.05.The results are:1.there is more hip joint angle flex when during accurate kick to the top target(target 1 and 3),and there is more knee joint angle flex during accurate kick to the top target(target 1 and 3) in the backswing.2.there is higher rectus femoris,vastus lateralis and,svastus medialis EMG activity during accurate kick to the top target(target 1 and 3).Suggestion: In this study, we found that the shooting action, in addition to the rectus femoris, vastus lateralis, vastus medialis and other large muscle groups, such as the anterior tibialis and gastrocnemius muscle and other smaller muscles will not only contract but also provide stability of ankle, and then increase the success rate of goal. Therefore this study may provide some data, to the coach or the players in order to use and understand of the characteristics of the site of muscle contraction, and then increase success rate of goal in penalty kick.