Journal articles on the topic 'Muscle activation pattern'
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1
Ravari, Reihaneh, and Hamid Reza Kobravi. "Identifying the Dynamics of Leg Muscle Activation During Human Gait Using Neural Oscillator and Fuzzy Compensator." International Clinical Neuroscience Journal 5, no. 3 (September 30, 2018): 106–12. http://dx.doi.org/10.15171/icnj.2018.21.
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Background: The goal of this study is to design a model in order to predict the muscle activation pattern because the muscle activation patterns contain valuable information about the muscle dynamics and movement patterns. Therefore, the goal of the presentation of this neural model is to identify the desired muscle activation patterns by Hopf chaotic oscillator during walking. Since the knee muscles activation has a significant effect on the movement pattern during walking, the main concentration of this study is to identify the knee muscles activation dynamics using a modeling technique. Methods: The electromyography (EMG) recording obtained from 5 healthy subjects that electrodes positioned on the tibialis-anterior (TA) and rectus femoris muscles on every 2 feet. In the proposed model, along with the chaotic oscillator, a fuzzy compensator was designed to face the unmolded dynamics. In fact, on the condition, the observed difference between the desired and actual activation patterns violate some specific quantitative ranges, the fuzzy compensator based on predefined rules modify the activity pattern produced by the Hopf oscillator. Results: Some quantitative measures used to evaluate the results. According to the achieved results, the proposed model could generate the trajectories, dynamics of which are similar to the muscle activation dynamics of the studied muscles. In this model, the generated activity pattern by the proposed model cannot follow the desired activity of the TA muscle as well as rectus femoris muscle. Conclusion: The similarity between the generated activity pattern by the model and the activation dynamics of Rectus- Femoris muscle was more in comparison with the similarity observed between activation pattern of Tibialis- Anterior and the pattern generated by the model. In other words, based on the recorded human data, the activation pattern of the Rectus- Femoris is more similar to a rhythmic pattern.
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Lin, Jian-Zhi, Wen-Yu Chiu, Wei-Hsun Tai, Yu-Xiang Hong, and Chung-Yu Chen. "Ankle Muscle Activations during Different Foot-Strike Patterns in Running." Sensors 21, no. 10 (May 14, 2021): 3422. http://dx.doi.org/10.3390/s21103422.
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This study analysed the landing performance and muscle activity of athletes in forefoot strike (FFS) and rearfoot strike (RFS) patterns. Ten male college participants were asked to perform two foot strikes patterns, each at a running speed of 6 km/h. Three inertial sensors and five EMG sensors as well as one 24 G accelerometer were synchronised to acquire joint kinematics parameters as well as muscle activation, respectively. In both the FFS and RFS patterns, according to the intraclass correlation coefficient, excellent reliability was found for landing performance and muscle activation. Paired t tests indicated significantly higher ankle plantar flexion in the FFS pattern. Moreover, biceps femoris (BF) and gastrocnemius medialis (GM) activation increased in the pre-stance phase of the FFS compared with that of RFS. The FFS pattern had significantly decreased tibialis anterior (TA) muscle activity compared with the RFS pattern during the pre-stance phase. The results demonstrated that the ankle strategy focused on controlling the foot strike pattern. The influence of the FFS pattern on muscle activity likely indicates that an athlete can increase both BF and GM muscles activity. Altered landing strategy in cases of FFS pattern may contribute both to the running efficiency and muscle activation of the lower extremity. Therefore, neuromuscular training and education are required to enable activation in dynamic running tasks.
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Wohlert, Amy B., and Lisa Goffman. "Human Perioral Muscle Activation Patterns." Journal of Speech, Language, and Hearing Research 37, no. 5 (October 1994): 1032–40. http://dx.doi.org/10.1044/jshr.3705.1032.
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Task-dependent human motor organization in the perioral region was examined in eight normal adults who performed oral tasks including lip protrusion, chewing, and speech. Zero phase-lag correlations among EMG signals recorded from quadrants surrounding the lips were calculated in order to determine patterns of motor coupling. Results indicated that the perioral musculature is flexible in output organization. Activv in all quadrants was highly positively correlated during the protrusion task. During the chewing task, correlations were moderate, with a stronger pattern bilaterally across the upper and lower lips. The speech tasks showed lower levels of correlation among the quadrants, but again the pattern was more highly correlated bilaterally than ipsilaterally. Results are compared to studies of oral muscle innervation in humans and animals and also are related to hypotheses of cortical control patterns for oral movement.
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Rosati, Samanta, Marco Ghislieri, Gregorio Dotti, Daniele Fortunato, Valentina Agostini, Marco Knaflitz, and Gabriella Balestra. "Evaluation of Muscle Function by Means of a Muscle-Specific and a Global Index." Sensors 21, no. 21 (October 29, 2021): 7186. http://dx.doi.org/10.3390/s21217186.
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Gait analysis applications in clinics are still uncommon, for three main reasons: (1) the considerable time needed to prepare the subject for the examination; (2) the lack of user-independent tools; (3) the large variability of muscle activation patterns observed in healthy and pathological subjects. Numerical indices quantifying the muscle coordination of a subject could enable clinicians to identify patterns that deviate from those of a reference population and to follow the progress of the subject after surgery or completing a rehabilitation program. In this work, we present two user-independent indices. First, a muscle-specific index (MFI) that quantifies the similarity of the activation pattern of a muscle of a specific subject with that of a reference population. Second, a global index (GFI) that provides a score of the overall activation of a muscle set. These two indices were tested on two groups of healthy and pathological children with encouraging results. Hence, the two indices will allow clinicians to assess the muscle activation, identifying muscles showing an abnormal activation pattern, and associate a functional score to every single muscle as well as to the entire muscle set. These opportunities could contribute to facilitating the diffusion of surface EMG analysis in clinics.
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Torres, Gonzalo, David Chorro, Archit Navandar, Javier Rueda, Luís Fernández, and Enrique Navarro. "Assessment of Hamstring: Quadriceps Coactivation without the Use of Maximum Voluntary Isometric Contraction." Applied Sciences 10, no. 5 (February 29, 2020): 1615. http://dx.doi.org/10.3390/app10051615.
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This study aimed to study the coactivation patterns of the hamstring and quadriceps muscle groups during submaximal strength exercises commonly used in injury prevention in soccer without the use of maximum voluntary isometric contraction testing. This was used to compare: (i) the inter-limb differences in muscle activation; (ii) the intra-muscular group activation pattern and (iii) the activation pattern during different phases of the exercise. Muscle activation was recorded by surface electromyography in 19 elite, male, youth soccer players. Participants performed the following: Bulgarian squat, lunge and squat. Electrical activity was recorded for the rectus femoris, vastus medialis, vastus lateralis, biceps femoris and semitendinosus. No significant inter-limb differences were found (F1, 13 = 619; p = 0.82; η2 = 0.045). Significant differences were found in the muscle activation between individual muscles within the quadriceps and hamstrings muscle group for each of the exercises: Bulgarian squat (F1,18 = 331: p < 0.001; η2 = 0.80), lunge (F4,72 = 114.5; p < 0.001; η2 = 0.86) and squat (F1,16 = 247.31; p < 0.001; η2 = 0.93). Differences were found between the different phases of each of the exercises (F2,26 = 52.27; p = 0.02; η2 = 0.80). The existence of an activation pattern of each of the muscles in the three proposed exercises could be used for muscle assessment and as a tool for reconditioning post-injury.
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Silva, Natália Sanches, Pedro Henrique Tavares Queiroz de Almeida, Paulo Vinicius Braga Mendes, Caio Sadao Medeiros Komino, José Marques Novo Jùnior, and Daniel Marinho Cezar Da Cruz. "Electromyographic Activity of the Upper Limb in Three Hand Function Tests." Hong Kong Journal of Occupational Therapy 29, no. 1 (February 16, 2017): 10–18. http://dx.doi.org/10.1016/j.hkjot.2016.11.003.
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Objective/Background Occupational therapists usually assess hand function through standardised tests, however, there is no consensus on how the scores assigned to hand dexterity can accurately measure hand function required for daily activities and few studies evaluate the movement patterns of the upper limbs during hand function tests. This study aimed to evaluate the differences in muscle activation patterns during the performance of three hand dexterity tests. Methods Twenty university students underwent a surface electromyographic (sEMG) assessment of eight upper limb muscles during the performance of the box and blocks test (BEST), nine-hole peg test (9HPT), and functional dexterity test (FDT). The description and comparison of each muscle activity during the test performance, gender differences, and the correlation between individual muscles’ sEMG activity were analysed through appropriate statistics. Results Increased activity of proximal muscles was found during the performance of BEST (p < .001). While a higher activation of the distal muscles occurred during the FDT and 9HPT performance, no differences were found between them. Comparisons of the sEMG activity revealed a significant increase in the muscle activation among women (p = .05). Strong and positive correlations (r > .5; p < .05) were observed between proximal and distal sEMG activities, suggesting a coordinate pattern of muscle activation during hand function tests. Conclusion The results suggested the existence of differences in the muscle activation pattern during the performance of hand function evaluations. Occupational therapists should be aware of unique muscle requirements and its impact on the results of dexterity tests during hand function evaluation.
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Torres, Gonzalo, Estrella Armada-Cortés, Javier Rueda, Alejandro F. San Juan, and Enrique Navarro. "Comparison of Hamstrings and Quadriceps Muscle Activation in Male and Female Professional Soccer Players." Applied Sciences 11, no. 2 (January 14, 2021): 738. http://dx.doi.org/10.3390/app11020738.
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(1) Background: this study aimed to determine if there are differences in quadriceps and hamstring muscle activation in professional male and female soccer players. (2) Methods: muscle activation was recorded by surface electromyography in 27 professional soccer players (19 male and 8 female). The players performed the Bulgarian squat and lunge exercises. Vastus medialis, vastus lateralis, rectus femoris, semitendinosus, and biceps femoris were the muscles analyzed. (3) Results: The statistical analysis of the hamstring:quadriceps ratio showed no significant differences (p > 0.05). Significant differences were found in the vastus medialis:vastus lateralis ratio for both the lunge exercise (t20 = 3.35; p = 0.001; d = 1.42) and the Bulgarian squat (t23 = 4.15; p < 0.001; d = 1.76). For the intragroup muscular pattern in the lunge and Bulgarian squat exercises, the female players showed higher activation for the vastus lateralis muscle (p < 0.001) than the male players and lower muscle activation in the vastus medialis. No significant differences were found in the rectus femoris, biceps remoris, and semitendinosus muscles (p > 0.05). (4) Conclusions: Differences were found in the medial ratio (vastus medialis: vastus lateralis). Moreover, regarding the intramuscular pattern, very consistent patterns have been found. In the quadriceps muscle: VM>VL>RF; in the hamstring muscle: ST>BF. These patterns could be very useful in the recovery process from an injury to return players to their highest performance.
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Vidhya, L., S. Saranya, and S. Poonguzhali. "Analysis of Lower Extremity Muscle Activation Using EMG." Applied Mechanics and Materials 573 (June 2014): 797–802. http://dx.doi.org/10.4028/www.scientific.net/amm.573.797.
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Electromyography (EMG) has been widely used as a tool to understand and distinguish between normal and pathological gait. This study aims at understanding the activation patterns of lower limb muscles viz. Gastrocnemius and Tibialis Anterior in the dominant leg of subjects with normal (n=5) as well as pathological (n=2) gait patterns. The paper presents a normative pattern of these muscles during normal walking condition from which the deviation of affected group from the control group is observed. For this analysis, Surface EMG signals along with Force Sensitive Resistor values are acquired. These surface EMG signals picked up during the muscle activity are interfaced with a PC via EMG acquisition system. The acquired signals were processed and analyzed which can be used for rehabilitative therapy planning.
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Dai, Chenyun, and Xiaogang Hu. "Extracting and Classifying Spatial Muscle Activation Patterns in Forearm Flexor Muscles Using High-Density Electromyogram Recordings." International Journal of Neural Systems 29, no. 01 (January 10, 2019): 1850025. http://dx.doi.org/10.1142/s0129065718500259.
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The human hand is capable of producing versatile yet precise movements largely owing to the complex neuromuscular systems that control our finger movement. This study seeks to quantify the spatial activation patterns of the forearm flexor muscles during individualized finger flexions. High-density (HD) surface electromyogram (sEMG) signals of forearm flexor muscles were obtained, and individual motor units were decomposed from the sEMG. Both macro-level spatial patterns of EMG activity and micro-level motor unit distributions were used to systematically characterize the forearm flexor activation patterns. Different features capturing the spatial patterns were extracted, and the unique patterns of forearm flexor activation were then quantified using pattern recognition approaches. We found that the forearm flexor spatial activation during the ring finger flexion was mostly distinct from other fingers, whereas the activation patterns of the middle finger were least distinguishable. However, all the different activation patterns can still be classified in high accuracy (94–100%) using pattern recognition. Our findings indicate that the partial overlapping of neural activation can limit accurate identification of specific finger movement based on limited recordings and sEMG features, and that HD sEMG recordings capturing detailed spatial activation patterns at both macro- and micro-levels are needed.
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Roh, Jinsook, William Z. Rymer, Eric J. Perreault, Seng Bum Yoo, and Randall F. Beer. "Alterations in upper limb muscle synergy structure in chronic stroke survivors." Journal of Neurophysiology 109, no. 3 (February 1, 2013): 768–81. http://dx.doi.org/10.1152/jn.00670.2012.
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Previous studies in neurologically intact subjects have shown that motor coordination can be described by task-dependent combinations of a few muscle synergies, defined here as a fixed pattern of activation across a set of muscles. Arm function in severely impaired stroke survivors is characterized by stereotypical postural and movement patterns involving the shoulder and elbow. Accordingly, we hypothesized that muscle synergy composition is altered in severely impaired stroke survivors. Using an isometric force matching protocol, we examined the spatial activation patterns of elbow and shoulder muscles in the affected arm of 10 stroke survivors (Fugl-Meyer <25/66) and in both arms of six age-matched controls. Underlying muscle synergies were identified using non-negative matrix factorization. In both groups, muscle activation patterns could be reconstructed by combinations of a few muscle synergies (typically 4). We did not find abnormal coupling of shoulder and elbow muscles within individual muscle synergies. In stroke survivors, as in controls, two of the synergies were comprised of isolated activation of the elbow flexors and extensors. However, muscle synergies involving proximal muscles exhibited consistent alterations following stroke. Unlike controls, the anterior deltoid was coactivated with medial and posterior deltoids within the shoulder abductor/extensor synergy and the shoulder adductor/flexor synergy in stroke was dominated by activation of pectoralis major, with limited anterior deltoid activation. Recruitment of the altered shoulder muscle synergies was strongly associated with abnormal task performance. Overall, our results suggest that an impaired control of the individual deltoid heads may contribute to poststroke deficits in arm function.
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Gottfried, S. B., and A. F. DiMarco. "Effect of intestinal afferent stimulation on pattern of respiratory muscle activation." Journal of Applied Physiology 66, no. 3 (March 1, 1989): 1455–61. http://dx.doi.org/10.1152/jappl.1989.66.3.1455.
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The purpose of the present study was to examine the reflex effects of mechanical stimulation of intestinal visceral afferents on the pattern of respiratory muscle activation. In 14 dogs anesthetized with pentobarbital sodium, electromyographic activity of the costal and crural diaphragm, parasternal intercostal, and upper airway respiratory muscles was measured during distension of the small intestine. Rib cage and abdominal motion and tidal volume were also recorded. Distension produced an immediate apnea (11.16 +/- 0.80 s). During the first postapneic breath, costal (43 +/- 7% control) and crural (64 +/- 6% control) activity were reduced (P less than 0.001). In contrast, intercostal (137 +/- 11%) and upper airway muscle activity, including alae nasi (157 +/- 16%), genioglossus (170 +/- 15%), and posterior cricoarytenoid muscles (142 +/- 7%) all increased (P less than 0.005). There was greater outward rib cage motion although the abdomen moved paradoxically inward during inspiration, resulting in a reduction in tidal volume (82 +/- 6% control) (P less than 0.005). Postvagotomy distension produced a similar apnea and subsequent reduction in costal and crural activity. However, enhancement of intercostal and upper airway muscle activation was abolished and there was a greater fall in tidal volume (65 +/- 14%). In conclusion, mechanical stimulation of intestinal afferents affects the various inspiratory muscles differently; nonvagal afferents produce an initial apnea and subsequent depression of diaphragm activity whereas vagal pathways mediate selective enhancement of intercostal and upper airway muscle activation.
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Ahn, A. N., J. K. Kang, M. A. Quitt, B. C. Davidson, and C. T. Nguyen. "Variability of neural activation during walking in humans: short heels and big calves." Biology Letters 7, no. 4 (February 2, 2011): 539–42. http://dx.doi.org/10.1098/rsbl.2010.1169.
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People come in different shapes and sizes. In particular, calf muscle size in humans varies considerably. One possible cause for the different shapes of calf muscles is the inherent difference in neural signals sent to these muscles during walking. In sedentary adults, the variability in neural control of the calf muscles was examined with muscle size, walking kinematics and limb morphometrics. Half the subjects walked while activating their medial gastrocnemius (MG) muscles more strongly than their lateral gastrocnemius (LG) muscles during most walking speeds (‘MG-biased’). The other subjects walked while activating their MG and LG muscles nearly equally (‘unbiased’). Those who walked with an MG-biased recruitment pattern also had thicker MG muscles and shorter heel lengths, or MG muscle moment arms, than unbiased walkers, but were similar in height, weight, lower limb length, foot length, and exhibited similar walking kinematics. The relatively less plastic skeletal system may drive calf muscle size and motor recruitment patterns of walking in humans.
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DiMarco, A. F., J. R. Romaniuk, K. E. Kowalski, and G. Supinski. "Pattern of expiratory muscle activation during lower thoracic spinal cord stimulation." Journal of Applied Physiology 86, no. 6 (June 1, 1999): 1881–89. http://dx.doi.org/10.1152/jappl.1999.86.6.1881.
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Large positive airway pressures (Paws) can be generated by lower thoracic spinal cord stimulation (SCS), which may be a useful method of restoring cough in spinal cord-injured patients. Optimal electrode placement, however, requires an assessment of the pattern of current spread during SCS. Studies were performed in anesthetized dogs to assess the pattern of expiratory muscle recruitment during SCS applied at different spinal cord levels. A multicontact stimulating electrode was positioned over the surface of the lower thoracic and upper lumbar spinal cord. Recording electromyographic electrodes were placed at several locations in the abdominal and internal intercostal muscles. SCS was applied at each lead, in separate trials, with single shocks of 0.2-ms duration. The intensity of stimulation was adjusted to determine the threshold for development of the compound action potential at each electrode lead. The values of current threshold for activation of each muscle formed parabolas with minimum values at specific spinal root levels. The slopes of the parabolas were relatively steep, indicating that the threshold for muscle activation increases rapidly at more cephalad and caudal sites. These results were compared with the effectiveness of SCS (50 Hz; train duration, 1–2 s) at different spinal cord levels to produce changes in Paw. Stimulation at the T9 and T10 spinal cord level resulted in the largest positive Paws with a single lead. At these sites, threshold values for activation of the internal intercostal (7–11th interspaces) upper portions of external oblique, rectus abdominis, and transversus abdominis were near their minimum. Threshold values for activation of the caudal portions of the abdominal muscles were high (>50 mA). Our results indicate that 1) activation of the more cephalad portions of the abdominal muscles is more important than activation of caudal regions in the generation of positive Paws and 2) it is not possible to achieve complete activation of the expiratory muscles with a single electrode lead by using modest current levels. In support of this latter conclusion, a two-electrode lead system results in more uniform expiratory muscle activation and significantly greater changes in Paw.
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Horak, F. B., and L. M. Nashner. "Central programming of postural movements: adaptation to altered support-surface configurations." Journal of Neurophysiology 55, no. 6 (June 1, 1986): 1369–81. http://dx.doi.org/10.1152/jn.1986.55.6.1369.
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We studied the extent to which automatic postural actions in standing human subjects are organized by a limited repertoire of central motor programs. Subjects stood on support surfaces of various lengths, which forced them to adopt different postural movement strategies to compensate for the same external perturbations. We assessed whether a continuum or a limited set of muscle activation patterns was used to produce different movement patterns and the extent to which movement patterns were influenced by prior experience. Exposing subjects standing on a normal support surface to brief forward and backward horizontal surface perturbations elicited relatively stereotyped patterns of leg and trunk muscle activation with 73- to 110-ms latencies. Activity began in the ankle joint muscles and then radiated in sequence to thigh and then trunk muscles on the same dorsal or ventral aspect of the body. This activation pattern exerted compensatory torques about the ankle joints, which restored equilibrium by moving the body center of mass forward or backward. This pattern has been termed the ankle strategy because it restores equilibrium by moving the body primarily around the ankle joints. To successfully maintain balance while standing on a support surface short in relation to foot length, subjects activated leg and trunk muscles at similar latencies but organized the activity differently. The trunk and thigh muscles antagonistic to those used in the ankle strategy were activated in the opposite proximal-to-distal sequence, whereas the ankle muscles were generally unresponsive. This activation pattern produced a compensatory horizontal shear force against the support surface but little, if any, ankle torque. This pattern has been termed the hip strategy, because the resulting motion is focused primarily about the hip joints. Exposing subjects to horizontal surface perturbations while standing on support surfaces intermediate in length between the shortest and longest elicited more complex postural movements and associated muscle activation patterns that resembled ankle and hip strategies combined in different temporal relations. These complex postural movements were executed with combinations of torque and horizontal shear forces and motions of ankle and hip joints. During the first 5-20 practice trials immediately following changes from one support surface length to another, response latencies were unchanged. The activation patterns, however, were complex and resembled the patterns observed during well-practiced stance on surfaces of intermediate lengths.(ABSTRACT TRUNCATED AT 400 WORDS)
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Griffin, D. M., H. M. Hudson, A. Belhaj-Saïf, B. J. McKiernan, and P. D. Cheney. "Do Corticomotoneuronal Cells Predict Target Muscle EMG Activity?" Journal of Neurophysiology 99, no. 3 (March 2008): 1169–986. http://dx.doi.org/10.1152/jn.00906.2007.
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Data from two rhesus macaques were used to investigate the pattern of cortical cell activation during reach-to-grasp movements in relation to the corresponding activation pattern of the cell's facilitated target muscles. The presence of postspike facilitation (PSpF) in spike-triggered averages (SpTAs) of electromyographic (EMG) activity was used to identify cortical neurons with excitatory synaptic linkages with motoneurons. EMG activity from 22 to 24 muscles of the forelimb was recorded together with the activity of M1 cortical neurons. The extent of covariation was characterized by 1) identifying the task segment containing the cell and target muscle activity peaks, 2) quantifying the timing and overlap between corticomotoneuronal (CM) cell and EMG peaks, and 3) applying Pearson correlation analysis to plots of CM cell firing rate versus EMG activity of the cell's facilitated muscles. At least one firing rate peak, for nearly all (95%) CM cells tested, matched a corresponding peak in the EMG activity of the cell's target muscles. Although some individual CM cells had very strong correlations with target muscles, overall, substantial disparities were common. We also investigated correlations for ensembles of CM cells sharing the same target muscle. The ensemble population activity of even a small number of CM cells influencing the same target muscle produced a relatively good match ( r ≥ 0.8) to target muscle EMG activity. Our results provide evidence in support of the notion that corticomotoneuronal output from primary motor cortex encodes movement in a framework of muscle-based parameters, specifically muscle-activation patterns as reflected in EMG activity.
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Nugent, Marilee M., and Theodore E. Milner. "Segmental specificity in belly dance mimics primal trunk locomotor patterns." Journal of Neurophysiology 117, no. 3 (March 1, 2017): 1100–1111. http://dx.doi.org/10.1152/jn.00693.2016.
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Belly dance was used to investigate control of rhythmic undulating trunk movements in humans. Activation patterns in lumbar erector spinae muscles were recorded using surface electromyography at four segmental levels spanning T10 to L4. Muscle activation patterns for movement tempos of 2 Hz, 3 Hz, and as fast as possible (up to 6 Hz) were compared to test the hypothesis that frequency modulates muscle timing, causing pattern changes analogous to gait transitions. Groups of trained and untrained female subjects were compared to test the hypothesis that experience modifies muscle coordination patterns and the capacity for selective motion of spinal segments. Three distinct coordination patterns were observed. An ipsilateral simultaneous pattern (S) and a diagonal synergy (D) dominated at lower frequencies. The S pattern was selected most often by novices and resembled the standing wave of activation underlying the alternating lateral trunk bending in salamander trotting. At 2 Hz, most trained subjects selected the D pattern, suggesting a greater capacity for segmental specificity compared with untrained subjects. At 3–4 Hz, there emerged an asynchronous pattern (A) analogous to the rostral-caudal traveling wave in salamander and lamprey swimming. The neural networks and mechanisms identified in primitive vertebrates, such as chains of coupled oscillators and segmental crossed inhibitory connections, could explain the patterns observed in this study in humans. Training allows modification of these patterns, possibly through improved capacity for selectively exciting or inhibiting segmental pattern generators. NEW & NOTEWORTHY Belly dance provides a novel approach for studying spinal cord neural circuits. New evidence suggests that primitive locomotor circuits may be conserved in humans. Erector spinae activation patterns during the hip shimmy at different tempos are similar to those observed in salamander walking and swimming. As movement frequency increases, a sequential pattern similar to lamprey swimming emerges, suggesting that primal involuntary control mechanisms dominate in fast lateral rhythmic spine undulations even in humans.
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Spudić, Darjan, Darjan Smajla, Michael David Burnard, and Nejc Šarabon. "Muscle Activation Sequence in Flywheel Squats." International Journal of Environmental Research and Public Health 18, no. 6 (March 19, 2021): 3168. http://dx.doi.org/10.3390/ijerph18063168.
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Background: Muscle coordination is important for rational and effective planning of therapeutic and exercise interventions using equipment that mimics functional movements. Our study was the first to assess muscle coordination during flywheel (FW) squats. Methods: Time-of-peak electromyographic activation order was assessed separately for 8, 4, and 3 leg muscles under four FW loads. A sequential rank agreement permutations tests (SRA) were conducted to assess activation order and Kendall’s tau was used to assess the concordance of activation order across subjects, loads and expected order of activation. Results: SRA revealed a latent muscle activation order at loads 0.05, 0.075, and 0.1, but not at 0.025 kg·m2. Kendall’s tau showed moderate-to-strong concordance between the expected (proximal-to-distal) and the observed muscle activation order only at a load 0.025 kg·m2, regardless of the number of muscles analyzed. Muscle activation order was highly concordant between loads 0.05, 0.075, and 0.1 kg·m2. Conclusions: The results show a specific role of each muscle during the FW squat that is load-dependent. While the lowest load follows the proximal-to-distal principle of muscle activation, higher loads lead to a reorganization of the underlying muscle coordination mechanisms. They require a specific and stable muscle coordination pattern that is not proximal-to-distal.
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Piovanelli, Enrico, Davide Piovesan, Shouhei Shirafuji, Becky Su, Natsue Yoshimura, Yousuke Ogata, and Jun Ota. "Towards a Simplified Estimation of Muscle Activation Pattern from MRI and EMG Using Electrical Network and Graph Theory." Sensors 20, no. 3 (January 28, 2020): 724. http://dx.doi.org/10.3390/s20030724.
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Muscle functional MRI (mfMRI) is an imaging technique that assess muscles’ activity, exploiting a shift in the T2-relaxation time between resting and active state on muscles. It is accompanied by the use of electromyography (EMG) to have a better understanding of the muscle electrophysiology; however, a technique merging MRI and EMG information has not been defined yet. In this paper, we present an anatomical and quantitative evaluation of a method our group recently introduced to quantify its validity in terms of muscle pattern estimation for four subjects during four isometric tasks. Muscle activation pattern are estimated using a resistive network to model the morphology in the MRI. An inverse problem is solved from sEMG data to assess muscle activation. The results have been validated with a comparison with physiological information and with the fitting on the electrodes space. On average, over 90% of the input sEMG information was able to be explained with the estimated muscle patterns. There is a match with anatomical information, even if a strong subjectivity is observed among subjects. With this paper we want to proof the method’s validity showing its potential in diagnostic and rehabilitation fields.
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Cappellini, G., Y. P. Ivanenko, R. E. Poppele, and F. Lacquaniti. "Motor Patterns in Human Walking and Running." Journal of Neurophysiology 95, no. 6 (June 2006): 3426–37. http://dx.doi.org/10.1152/jn.00081.2006.
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Despite distinct differences between walking and running, the two types of human locomotion are likely to be controlled by shared pattern-generating networks. However, the differences between their kinematics and kinetics imply that corresponding muscle activations may also be quite different. We examined the differences between walking and running by recording kinematics and electromyographic (EMG) activity in 32 ipsilateral limb and trunk muscles during human locomotion, and compared the effects of speed (3–12 km/h) and gait. We found that the timing of muscle activation was accounted for by five basic temporal activation components during running as we previously found for walking. Each component was loaded on similar sets of leg muscles in both gaits but generally on different sets of upper trunk and shoulder muscles. The major difference between walking and running was that one temporal component, occurring during stance, was shifted to an earlier phase in the step cycle during running. These muscle activation differences between gaits did not simply depend on locomotion speed as shown by recordings during each gait over the same range of speeds (5–9 km/h). The results are consistent with an organization of locomotion motor programs having two parts, one that organizes muscle activation during swing and another during stance and the transition to swing. The timing shift between walking and running reflects therefore the difference in the relative duration of the stance phase in the two gaits.
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Butler, Victoria J., Robyn Branicky, Eviatar Yemini, Jana F. Liewald, Alexander Gottschalk, Rex A. Kerr, Dmitri B. Chklovskii, and William R. Schafer. "A consistent muscle activation strategy underlies crawling and swimming in Caenorhabditis elegans." Journal of The Royal Society Interface 12, no. 102 (January 2015): 20140963. http://dx.doi.org/10.1098/rsif.2014.0963.
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Although undulatory swimming is observed in many organisms, the neuromuscular basis for undulatory movement patterns is not well understood. To better understand the basis for the generation of these movement patterns, we studied muscle activity in the nematode Caenorhabditis elegans. Caenorhabditis elegans exhibits a range of locomotion patterns: in low viscosity fluids the undulation has a wavelength longer than the body and propagates rapidly, while in high viscosity fluids or on agar media the undulatory waves are shorter and slower. Theoretical treatment of observed behaviour has suggested a large change in force–posture relationships at different viscosities, but analysis of bend propagation suggests that short-range proprioceptive feedback is used to control and generate body bends. How muscles could be activated in a way consistent with both these results is unclear. We therefore combined automated worm tracking with calcium imaging to determine muscle activation strategy in a variety of external substrates. Remarkably, we observed that across locomotion patterns spanning a threefold change in wavelength, peak muscle activation occurs approximately 45° (1/8th of a cycle) ahead of peak midline curvature. Although the location of peak force is predicted to vary widely, the activation pattern is consistent with required force in a model incorporating putative length- and velocity-dependence of muscle strength. Furthermore, a linear combination of local curvature and velocity can match the pattern of activation. This suggests that proprioception can enable the worm to swim effectively while working within the limitations of muscle biomechanics and neural control.
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Carroll, Andrew M., Ashley M. Ambrose, Terri A. Anderson, and David J. Coughlin. "Feeding muscles scale differently from swimming muscles in sunfish (Centrarchidae)." Biology Letters 5, no. 2 (December 23, 2008): 274–77. http://dx.doi.org/10.1098/rsbl.2008.0647.
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The physiological properties of vertebrate skeletal muscle typically show a scaling pattern of slower contractile properties with size. In fishes, the myotomal or swimming muscle reportedly follows this pattern, showing slower muscle activation, relaxation and maximum shortening velocity ( V max ) with an increase in body size. We asked if the muscles involved in suction feeding by fishes would follow the same pattern. We hypothesized that feeding muscles in fishes that feed on evasive prey are under selection to maintain high power output and therefore would not show slower contractile properties with size. To test this, we compared contractile properties in feeding muscles (epaxial and sternohyoideus) and swimming muscle (myotomal) for two members of the family Centrarchidae (sunfish): the bluegill ( Lepomis macrochirus ) and the largemouth bass ( Micropterus salmoides ). Consistent with our predictions, the V max of myotomal muscle in both species slowed with size, while the epaxials showed no significant change in V max with size. In the sternohyoideus, V max slowed with size in the bluegill but increased with size in the bass. The results indicate that scaling patterns of contractile properties appear to be more closely tied to muscle function (i.e. locomotion versus feeding) than overall patterns of size.
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Sloniger, Mark A., Kirk J. Cureton, Barry M. Prior, and Ellen M. Evans. "Lower extremity muscle activation during horizontal and uphill running." Journal of Applied Physiology 83, no. 6 (December 1, 1997): 2073–79. http://dx.doi.org/10.1152/jappl.1997.83.6.2073.
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Sloniger, Mark A., Kirk J. Cureton, Barry M. Prior, and Ellen M. Evans. Lower extremity muscle activation during horizontal and uphill running. J. Appl. Physiol. 83(6): 2073–2079, 1997.—To provide more comprehensive information on the extent and pattern of muscle activation during running, we determined lower extremity muscle activation by using exercise-induced contrast shifts in magnetic resonance (MR) images during horizontal and uphill high-intensity (115% of peak oxygen uptake) running to exhaustion (2.0–3.9 min) in 12 young women. The mean percentage of muscle volume activated in the right lower extremity was significantly ( P <0.05) greater during uphill (73 ± 7%) than during horizontal (67 ± 8%) running. The percentage of 13 individual muscles or groups activated varied from 41 to 90% during horizontal running and from 44 to 83% during uphill running. During horizontal running, the muscles or groups most activated were the adductors (90 ± 5%), semitendinosus (86 ± 13%), gracilis (76 ± 20%), biceps femoris (76 ± 12%), and semimembranosus (75 ± 12%). During uphill running, the muscles most activated were the adductors (83 ± 8%), biceps femoris (79 ± 7%), gluteal group (79 ± 11%), gastrocnemius (76 ± 15%), and vastus group (75 ± 13%). Compared with horizontal running, uphill running required considerably greater activation of the vastus group (23%) and soleus (14%) and less activation of the rectus femoris (29%), gracilis (18%), and semitendinosus (17%). We conclude that during high-intensity horizontal and uphill running to exhaustion, lasting 2–3 min, muscles of the lower extremity are not maximally activated, suggesting there is a limit to the extent to which additional muscle mass recruitment can be utilized to meet the demand for force and energy. Greater total muscle activation during exhaustive uphill than during horizontal running is achieved through an altered pattern of muscle activation that involves increased use of some muscles and less use of others.
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Swanik, Kathleen A., Kellie Huxel Bliven, and Charles Buz Swanik. "Rotator-Cuff Muscle-Recruitment Strategies During Shoulder Rehabilitation Exercises." Journal of Sport Rehabilitation 20, no. 4 (November 2011): 471–86. http://dx.doi.org/10.1123/jsr.20.4.471.
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Context:There are contradictory data on optimal muscle-activation strategies for restoring shoulder stability. Further investigation of neuromuscular-control strategies for glenohumeral-joint stability will guide clinicians in decisions regarding appropriate rehabilitation exercises.Objectives:To determine whether subscapularis, infraspinatus, and teres minor (anteroposterior force couple) muscle activation differ between 4 shoulder exercises and describe coactivation ratios and individual muscle-recruitment characteristics of rotator-cuff muscles throughout each shoulder exercise.Design:Crossover.Setting:Laboratory.Participants:healthy, physically active men, age 20.55 ± 2.0 y.Interventions:4 rehabilitation exercises: pitchback, PNF D2 pattern with tubing, push-up plus, and slide board.Main Outcomes Measures:Mean coactivation level, coactivation-ratio patterns, and level (area) of muscle-activation patterns of the subscapularis, infraspinatus, and teres minor throughout each exercise.Results:Coactivation levels varied throughout each exercise. Subscapularis activity was consistently higher than that of the infraspinatus and teres minor combined at the start of each exercise and in end ranges of motion. Individual muscle-recruitment levels in the subscapularis were also different between exercises.Conclusion:Results provide descriptive data for determining normative coactivation-ratio values for muscle recruitment for the functional exercises studied. Differences in subscapularis activation suggest a reliance to resist anteriorly directed forces.
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Karahan, Menekşe, and Bülent Sabri Cığalı. "Assessment of hip muscles by surface EMG in gait analysis." Anatomy 14, no. 2 (August 31, 2020): 86–90. http://dx.doi.org/10.2399/ana.20.039.
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Objectives: The rectus femoris muscle flexes the thigh, while the gluteus maximus muscle extends it. Understanding the activations of these two muscles that function in opposition to each other during walking facilitates the interpretation of gait pathologies. The aim of this study was to evaluate the activations of these muscles during walking by using the surface electromyography (EMG) technique. Methods: Twenty female volunteers aged 18–26 years participated in our study. The electrical activation of the rectus femoris and gluteus maximus muscles of the participants was simultaneously evaluated by gait analysis. At the same time, spatiotemporal parameters and phase parameters were obtained. Results: The activation pattern of both muscles was found to be similar. Both muscles reached the highest activation in the swing phase. The lowest activation was also seen in the pre-swing phase. Both muscles were observed to be active in the loading and single-limb support phases. Conclusion: The fact that these two antagonists muscles are active at the same time suggests that one is functioning concentrically, while the other eccentrically. Thus, stabilization of hip joint is provided when the body moves forward.
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Delvolvé, Isabelle, Tiaza Bem, and Jean-Marie Cabelguen. "Epaxial and Limb Muscle Activity During Swimming and Terrestrial Stepping in the Adult Newt, Pleurodeles waltl." Journal of Neurophysiology 78, no. 2 (August 1, 1997): 638–50. http://dx.doi.org/10.1152/jn.1997.78.2.638.
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Delvolvé, Isabelle, Tiaza Bem, and Jean-Marie Cabelguen. Epaxial and limb muscle activity during swimming and terrestrial stepping in the adult newt, Pleurodeles waltl. J. Neurophysiol. 78: 638–650, 1997. We have investigated the patterns of activation of epaxial musculature during both swimming and overground stepping in an adult newt ( Pleurodeles waltl) with the use of electromyographic (EMG) recordings from different sites of the myomeric muscle dorsalis trunci along the body axis. The locomotor patterns of some limb muscles have also been investigated. During swimming, the epaxial myomeres are rhythmically active, with a strict alternation between opposite myomeres located at the same longitudinal site. The pattern of intersegmental coordination consists of three successively initiated waves of EMG activity passing posteriorly along the anterior trunk, the midtrunk, and the posterior trunk, respectively. Swimming is also characterized by a tonic activation of forelimb (dorsalis scapulae and extensor ulnae) and hindlimb (puboischiotibialis and puboischiofemoralis internus) muscles and a rhythmic activation of muscles (latissimus dorsi and caudofemoralis) acting both on limb and body axis. The latter matched the activation pattern of epaxial myomeres at the similar vertebral level. During overground stepping, the midtrunk myomeres express single synchronous bursts whereas the myomeres of the anterior trunk and those of the posterior trunk display a double bursting pattern in the form of two waves of EMG activity propagating in opposite directions. During overground stepping, the limb muscles and muscles acting on both limb and body axis were found to be rhythmically active and usually displayed a double bursting pattern. The main conclusion of this investigation is that the patterns of intersegmental coordination during both swimming and overground stepping in the adult newt are related to the presence of limbs and that they can be considered as hybrid lampreylike patterns. Thus it is hypothesized that, in newt, a chain of coupled segmental oscillatory networks, similar to that which constitutes the central pattern generator (CPG) for swimming in the lamprey, can account for both trunk motor patterns if it is influenced by limb CPGs in a way depending on the locomotor mode. During swimming, the segmental networks located close to the girdles receive extra tonic excitation coming from the limb CPGs, whereas during stepping, the axial CPGs are entrained to some extent by the limb oscillators.
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Kostraba, Britt, Yi-Ning Wu, Pei-Chun Kao, Caroline Stark, Sheng-Che Yen, and Jinsook Roh. "Muscle activation pattern during self-propelled treadmill walking." Journal of Physical Therapy Science 30, no. 8 (2018): 1069–72. http://dx.doi.org/10.1589/jpts.30.1069.
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Mondal, Pritish, Mutasim Abu-Hasan, Abhishek Saha, Teresa Pitts, Melanie Rose, Donald C. Bolser, and Paul W. Davenport. "Effect of laparotomy on respiratory muscle activation pattern." Physiological Reports 4, no. 1 (January 2016): e12668. http://dx.doi.org/10.14814/phy2.12668.
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Wade, Logan, Glen A. Lichtwark, and Dominic J. Farris. "Joint and muscle-tendon coordination strategies during submaximal jumping." Journal of Applied Physiology 128, no. 3 (March 1, 2020): 596–603. http://dx.doi.org/10.1152/japplphysiol.00293.2019.
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Previous research has demonstrated that during submaximal jumping humans prioritize reducing energy consumption by minimizing countermovement depth. However, sometimes movement is constrained to a nonpreferred pattern, and this requires adaptation of neural control that accounts for complex interactions between muscle architecture, muscle properties, and task demands. This study compared submaximal jumping with either a preferred or a deep countermovement depth to examine how joint and muscle mechanics are integrated into the adaptation of coordination strategies in the deep condition. Three-dimensional motion capture, two force plates, electromyography, and ultrasonography were used to examine changes in joint kinetics and kinematics, muscle activation, and muscle kinematics for the lateral gastrocnemius and soleus. Results demonstrated that a decrease in ankle joint work during the deep countermovement depth was due to increased knee flexion, leading to unfavorably short biarticular muscle lengths and reduced active fascicle length change during ankle plantar flexion. Therefore, ankle joint work was likely decreased because of reduced active fascicle length change and operating position on the force-length relationship. Hip joint work was significantly increased as a result of altered muscle activation strategies, likely due to a substantially greater hip extensor muscle activation period compared with plantar flexor muscles during jumping. Therefore, coordination strategies at individual joints are likely influenced by time availability, where a short plantar flexor activation time results in dependence on muscle properties, instead of simply altering muscle activation, while the longer time for contraction of muscles at the hip allows for adjustments to voluntary neural control. NEW & NOTEWORTHY Using human jumping as a model, we show that adapting movement patterns to altered task demands is achieved differently by muscles across the leg. Because of proximal-to-distal sequencing, distal muscles (i.e., plantar flexors) have reduced activation periods and, as a result, rely on muscle contractile properties (force-length relationship) for adjusting joint kinetics. For proximal muscles that have greater time availability, voluntary activation is modulated to adjust muscle outputs.
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Gorassini, Monica A., Jonathan A. Norton, Jennifer Nevett-Duchcherer, Francois D. Roy, and Jaynie F. Yang. "Changes in Locomotor Muscle Activity After Treadmill Training in Subjects With Incomplete Spinal Cord Injury." Journal of Neurophysiology 101, no. 2 (February 2009): 969–79. http://dx.doi.org/10.1152/jn.91131.2008.
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Intensive treadmill training after incomplete spinal cord injury can improve functional walking abilities. To determine the changes in muscle activation patterns that are associated with improvements in walking, we measured the electromyography (EMG) of leg muscles in 17 individuals with incomplete spinal cord injury during similar walking conditions both before and after training. Specific differences were observed between subjects that eventually gained functional improvements in overground walking (responders), compared with subjects where treadmill training was ineffective (nonresponders). Although both groups developed a more regular and less clonic EMG pattern on the treadmill, it was only the tibialis anterior and hamstring muscles in the responders that displayed increases in EMG activation. Likewise, only the responders demonstrated decreases in burst duration and cocontraction of proximal (hamstrings and quadriceps) muscle activity. Surprisingly, the proximal muscle activity in the responders, unlike nonresponders, was three- to fourfold greater than that in uninjured control subjects walking at similar speeds and level of body weight support, suggesting that the ability to modify muscle activation patterns after injury may predict the ability of subjects to further compensate in response to motor training. In summary, increases in the amount and decreases in the duration of EMG activity of specific muscles are associated with functional recovery of walking skills after treadmill training in subjects that are able to modify muscle activity patterns following incomplete spinal cord injury.
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Kim, Jwa-jun, So-youn Ann, and Se-yeon Park. "Comparison of Diagonal Shoulder Exercises With and Without Visual Trace." International Journal of Athletic Therapy and Training 20, no. 1 (January 2015): 52–56. http://dx.doi.org/10.1123/ijatt.2014-0062.
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Objectives:The aim of this study was to investigate the effects of visual trace on shoulder muscle activation during diagonal pattern of exercises. Sixteen healthy male participants volunteered to participate.Design:Repeated-measure design.Setting:Laboratory setting.Participants:Sixteen physically active male participants volunteered to participate.Intervention:Five muscles of the shoulder were investigated during standing performance of diagonal shoulder exercises with and without visual trace. Two patterns of the diagonal exercises were used: diagonal 1 flexion (D1F) and diagonal 2 fexion (D2F). Two-way repeated measures analysis of variance was used, with factors being the presence of visual trace and exercise variations.Main Outcome Measure:Electromyography (EMG).Results:The average muscle activity values of the lower trapezius and anterior deltoid were higher with the D2F compared with the D1F (P < .05). The visual trace effect was observed within the serratus anterior, with values significantly greater in exercise with visual trace (P < .05). There was a significant increase of the lower trapezius during the exercise with the visual trace condition compared with the exercise without visual trace, which was only observed during D2F (P < .05).Conclusions:Present results suggest that the D2F exercise pattern is effective for activating lower trapezius and anterior deltoid muscles. The visual trace condition has the additional advantage of activating the scapulothoracic muscle activities depending on the specific pattern of diagonal shoulder exercise.
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KAWASHIMA, Noritaka, and Tomoki MITA. "1017 Muscle activation pattern in the residual stamp muscles in forearm amputees." Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 2009.22 (2010): 181. http://dx.doi.org/10.1299/jsmebio.2009.22.181.
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Maladen, Ryan D., Ramu Perumal, Anthony S. Wexler, and Stuart A. Binder-Macleod. "Effects of activation pattern on nonisometric human skeletal muscle performance." Journal of Applied Physiology 102, no. 5 (May 2007): 1985–91. http://dx.doi.org/10.1152/japplphysiol.00729.2006.
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During volitional muscle activation, motor units often fire with varying discharge patterns that include brief, high-frequency bursts of activity. These variations in the activation rate allow the central nervous system to precisely control the forces produced by the muscle. The present study explores how varying the instantaneous frequency of stimulation pulses within a train affects nonisometric muscle performance. The peak excursion produced in response to each stimulation train was considered as the primary measure of muscle performance. The results showed that at each frequency tested between 10 and 50 Hz, variable-frequency trains that took advantage of the catchlike property of skeletal muscle produced greater excursions than constant-frequency trains. In addition, variable-frequency trains that could achieve targeted trajectories with fewer pulses than constant-frequency trains were identified. These findings suggest that similar to voluntary muscle activation patterns, varying the instantaneous frequency within a train of pulses can be used to improve muscle performance during functional electrical stimulation.
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Multani, N. K., Singh Sonia, Sorabh Sharma, and Ralmila Ravinder Kaur. "Electromyography Based Analysis of the Impact of Ageing on Muscle Activation Pattern during Static and Dynamic Balance Control Tasks: A Systematic Review." Asian Pacific Journal of Health Sciences 9, no. 3 (April 16, 2022): 71–75. http://dx.doi.org/10.21276/apjhs.2022.9.3.15.
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The present systematic review was done, to examine the impact of aging on posture control mechanisms in terms of muscle activity and sway patterns. English language articles describing effects of aging on muscle activation pattern during balance control tasks using electromyography methods published from 2000 to 2019 were identified. Studies were compared with regards to study population, postural tasks, perturbations, muscle inclusion, and outcome measures. All the included studies (N-9) exhibited increased postural sway among elderly in contrast to young population. In contrast, inconsistency was observed in the muscle activation pattern, muscle dependency, and muscle co-contractions among the studies. Altogether, the findings of the review suggest that the aging causes alterations in muscle activity in order to maintain balance during challenging situations; however, the studies do not elucidate these changes across the ages.
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KAK, D. W., A. R. ANITA, N. M. NIZLAN, I. NORMALA, N. A. ABDUL JALIL, and S. V. WONG. "COMPARISON OF NECK MUSCLE ELECTROMYOGRAPHY ACTIVITY IN RESPONSE TO EXTERNAL FORCE BETWEEN STATIC AND DYNAMIC LOADING." Journal of Mechanics in Medicine and Biology 19, no. 04 (June 2019): 1850034. http://dx.doi.org/10.1142/s0219519418500343.
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Understanding the behavior of neck muscles is essential to accurately simulate the human head-neck segment movement especially for low-speed motor vehicle crash situation. Some head-neck mathematical models were designed using neck muscle activation behavior in isometric contraction (static loading) as the properties of neck muscle activation. However, neck muscle activation pattern and strength capability may vary between static and dynamic loading. This study aimed to determine the differences between neck muscle activation level under static and dynamic loading. A neck strength test involving 22 human volunteers was conducted with two different tasks in extension and flexion direction with three different loads. The neck muscle activation level is determined through measuring the electromyography (EMG) responses of selected flexor and extensor muscles using surface bilateral electrode and recorded. The findings showed that neck muscle activation level was significantly greater in dynamic loading than static loading ([Formula: see text]). These implied that more efforts from neck muscles were required to resist against dynamic loading than static loading. Nonetheless, the differences in EMG activities between these two loading conditions progressively decreased when more loads were applied. This study has established an empirical model to describe the relationship between neck muscle activation level and force output for both loading condition in flexion and extension.
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Ward, M. E., A. Deschamps, C. Roussos, and S. N. Hussain. "Effect of phrenic afferent stimulation on pattern of respiratory muscle activation." Journal of Applied Physiology 73, no. 2 (August 1, 1992): 563–70. http://dx.doi.org/10.1152/jappl.1992.73.2.563.
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Ventilation and electromyogram (EMG) activities of the right hemidiaphragm, parasternal intercostal, triangularis sterni, transversus abdominis, genioglossus, and alae nasi muscles were measured before and during central stimulation of the left thoracic phrenic nerve in 10 alpha-chloralose anesthetized vagotomized dogs. Pressure in the carotid sinuses was fixed to maintain baroreflex activity constant. The nerve was stimulated for 1 min with a frequency of 40 Hz and stimulus duration of 1 ms at voltages of 5, 10, 20, and 30 times twitch threshold (TT). At five times TT, no change in ventilation or EMG activity occurred. At 10 times TT, neither tidal volume nor breathing frequency increased sufficiently to reach statistical significance, although the change in their product (minute ventilation) was significant (P less than 0.05). At 20 and 30 times TT, increases in both breathing frequency and tidal volume were significant. At these stimulus intensities, the increases in ventilation were accompanied by approximately equal increases in the activity of the diaphragm, parasternal, and alae nasi muscles. The increase in genioglossus activity was much greater than that of the other inspiratory muscles. Phrenic nerve stimulation also elicited inhomogeneous activation of the expiratory muscles. The transversus abdominis activity increased significantly at intensities from 10 to 30 times TT, whereas the activity of the triangularis sterni remained unchanged. The high stimulation intensities required suggest that the activation of afferent fiber groups III and IV is involved in the response. We conclude that thin-fiber phrenic afferent activation exerts a nonuniform effect on the upper airway, rib cage, and abdominal muscles and may play a role in the control of respiratory muscle recruitment.
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Roberts, Thomas J. "Some Challenges of Playing with Power: Does Complex Energy Flow Constrain Neuromuscular Performance?" Integrative and Comparative Biology 59, no. 6 (June 26, 2019): 1619–28. http://dx.doi.org/10.1093/icb/icz108.
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Abstract Many studies of the flow of energy between the body, muscles, and elastic elements highlight advantages of the storage and recovery of elastic energy. The spring-like action of structures associated with muscles allows for movements that are less costly, more powerful and safer than would be possible with contractile elements alone. But these actions also present challenges that might not be present if the pattern of energy flow were simpler, for example, if power were always applied directly from muscle to motions of the body. Muscle is under the direct control of the nervous system, and precise modulation of activity can allow for finely controlled displacement and force. Elastic structures deform under load in a predictable way, but are not under direct control, thus both displacement and the flow of energy act at the mercy of the mechanical interaction of muscle and forces associated with movement. Studies on isolated muscle-tendon units highlight the challenges of controlling such systems. A carefully tuned activation pattern is necessary for effective cycling of energy between tendon and the environment; most activation patterns lead to futile cycling of energy between tendon and muscle. In power-amplified systems, “elastic backfire” sometimes occurs, where energy loaded into tendon acts to lengthen active muscles, rather than accelerate the body. Classic models of proprioception that rely on muscle spindle organs for sensing muscle and joint displacement illustrate how elastic structures might influence sensory feedback by decoupling joint movement from muscle fiber displacements. The significance of the complex flow of energy between muscles, elastic elements and the body for neuromotor control is worth exploring.
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Parsons, David, and Wendy Gilleard. "The Effect of Patellar Taping on Quadriceps Activity Onset in the Absence of Pain." Journal of Applied Biomechanics 15, no. 4 (November 1999): 373–80. http://dx.doi.org/10.1123/jab.15.4.373.
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Patellofemoral taping is a technique used in the management of patellofemoral pain that has been shown to alter the pattern of muscle activation onset in symptomatic subjects. It is unknown, however, if this taping technique directly influences the patterns of muscle activity that controls patella position or if its benefits are more related to the effect of pain reduction. The purpose of this study was to investigate the effect of a taping technique on the muscle activation onset of selected quadriceps muscles where pain was not a confounding factor. Thirteen asymptomatic subjects completed a stair ascent and descent task with the right patella untaped and taped for a medial patella glide. Muscle activation onset was determined by computer algorithm from surface EMG of vastus lateralis (VL) and vastus medialis obliquus (VMO). Taping significantly delayed the muscle activation onset of VMO and VL during stair ascent. There was no significant change for stair descent. This effect may be an attempt by the motor control system to counter the mechanical effect of patella perturbation or may be due to cutaneous stimulation affecting threshold or recruitment of motor units.
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Hoffman, Donna S., and Peter L. Strick. "Step-Tracking Movements of the Wrist. IV. Muscle Activity Associated With Movements in Different Directions." Journal of Neurophysiology 81, no. 1 (January 1, 1999): 319–33. http://dx.doi.org/10.1152/jn.1999.81.1.319.
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Hoffman, Donna S. and Peter L. Strick. Step-tracking movements of the wrist. IV. Muscle activity associated with movements in different directions. J. Neurophysiol. 81: 319–333, 1999. We examined the patterns of muscle activity associated with multiple directions of step-tracking movements of the wrist in humans and monkeys. Human subjects made wrist movements to 12 different targets that required varying amounts of flexion-extension and radial-ulnar deviation. Wrist muscles displayed two patterns of electromyographic (EMG) modulation as movement direction changed: amplitude graded and temporally shifted. The amplitude-graded pattern was characterized by modulation of the quantity of muscle activity that occurred during two distinct time periods, an agonist burst interval that began before movement onset and an antagonist burst interval that began just after movement onset. The timing of muscle activity over the two intervals showed little variation with changes in movement direction. For some directions of movement, EMG activity was present over both time intervals, resulting in “double bursts.” Modulation of activity during the agonist burst interval was particularly systematic and was well fit by a cosine function. In contrast, the temporally shifted pattern was characterized by a gradual change in the timing of a single burst of muscle activity. The burst occurred at a time intermediate between the agonist and antagonist burst intervals. The temporally shifted pattern was seen less frequently than the amplitude-graded pattern and was present only in selected wrist muscles for specific directions of movement. Monkeys made wrist movements to 8–16 different targets that required varying amounts of flexion-extension and radial-ulnar deviation. These movements were performed more slowly than those of human subjects. The wrist muscles of the monkeys we examined displayed the amplitude-graded pattern of activity but not the temporally shifted pattern. Stimulation of individual wrist muscles in monkeys resulted in wrist movements that were markedly curved, particularly for the wrist extensors. These results indicate that step-tracking movements of the wrist are generated mainly by using the amplitude-graded pattern to modulate muscle activity. We propose that this pattern reflects a central process that decomposes an intended movement into an agonist, “propulsive” component and an antagonist, “braking” component. Separate bursts of muscle activity then are generated to control each component. On the other hand, we argue that the temporally shifted pattern may function to reduce the amount of movement curvature associated with the activation of wrist muscles.
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VOGT, L., W. BANZER, K. PFEIFER, and R. GALM. "Muscle Activation Pattern of Hip Arthroplasty Patients in Walking." Research in Sports Medicine 12, no. 3 (July 2004): 191–99. http://dx.doi.org/10.1080/15438620490497503.
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Binder-Macleod, Stuart A., Samuel C. K. Lee, David W. Russ, and Lorin J. Kucharski. "Effects of activation pattern on human skeletal muscle fatigue." Muscle & Nerve 21, no. 9 (September 1998): 1145–52. http://dx.doi.org/10.1002/(sici)1097-4598(199809)21:9<1145::aid-mus5>3.0.co;2-7.
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Weiss, Erica J., and Martha Flanders. "Muscular and Postural Synergies of the Human Hand." Journal of Neurophysiology 92, no. 1 (July 2004): 523–35. http://dx.doi.org/10.1152/jn.01265.2003.
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Because humans have limited ability to independently control the many joints of the hand, a wide variety of hand shapes can be characterized as a weighted combination of just two or three main patterns of covariation in joint rotations, or “postural synergies.” The present study sought to align muscle synergies with these main postural synergies and to describe the form of membership of motor units in these postural/muscle synergies. Seventeen joint angles and the electromyographic (EMG) activities of several hand muscles (both intrinsic and extrinsic muscles) were recorded while human subjects held the hand statically in 52 specific shapes (i.e., shaping the hand around 26 commonly grasped objects or forming the 26 letter shapes of a manual alphabet). Principal-components analysis revealed several patterns of muscle synergy, some of which represented either coactivation of all hand muscles, or reciprocal patterns of activity (above and below average levels) in the intrinsic index finger and thumb muscles or (to a lesser extent) in the extrinsic four-tendoned extensor and flexor muscles. Single- and multiunit activity was generally a multimodal function of whole hand shape. This implies that motor-unit activation does not align with a single synergy; instead, motor units participate in multiple muscle synergies. Thus it appears that the organization of the global pattern of hand muscle activation is highly distributed. This organization mirrors the highly fractured somatotopy of cortical hand representations and may provide an ideal substrate for motor learning and recovery from injury.
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Trimarchi, J. R., and A. M. Schneiderman. "Different neural pathways coordinate Drosophila flight initiations evoked by visual and olfactory stimuli." Journal of Experimental Biology 198, no. 5 (May 1, 1995): 1099–104. http://dx.doi.org/10.1242/jeb.198.5.1099.
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To determine the role played by the giant fiber interneurons (GFs) in coordinating the jumping stages of visually elicited and olfactory-induced fight initiation we have recorded extracellularly from the cervical connective nerve during flight initiation. A spike is recorded from the cervical connective upon brain stimulation that has the same threshold as does activation of the tergotrochanteral muscle (TTM) and dorsal longitudinal muscles (DLMs). A consistent time interval occurs between the spike and activation of the TTM. Thus, the spike probably results from activity in the GFs. The time intervals between the spike and activation of the TTM during GF stimulation and visually elicited flight initiation are similar. These results suggest that the GFs coordinate the activation of the TTM and DLMs during the jumping stage of visually elicited flight initiation. A spike is also recorded from the cervical connective during olfactory-induced flight initiations, but its shape and the time interval between it and activation of the TTM is different from that observed during GF stimulation. Although some olfactory-induced flight initiations exhibit a pattern of muscle activation, olfactory-induced flight initiations exhibit a pattern of muscle activation indistinguishable from that evoked by GF stimulation, our results indicate that regardless of the pattern of muscle activation, olfactory-induced flight initiations are not coordinated by the GF circuit. The sterotypic sequence and timing of activation of TTM and DLMs characteristic of the GF pathway can, therefore, be evoked by neurons other than those constituting the GF pathway.
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Hug, François, Nicolas A. Turpin, Antoine Couturier, and Sylvain Dorel. "Consistency of muscle synergies during pedaling across different mechanical constraints." Journal of Neurophysiology 106, no. 1 (July 2011): 91–103. http://dx.doi.org/10.1152/jn.01096.2010.
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The purpose of the present study was to determine whether muscle synergies are constrained by changes in the mechanics of pedaling. The decomposition algorithm used to identify muscle synergies was based on two components: “muscle synergy vectors,” which represent the relative weighting of each muscle within each synergy, and “synergy activation coefficients,” which represent the relative contribution of muscle synergy to the overall muscle activity pattern. We hypothesized that muscle synergy vectors would remain fixed but that synergy activation coefficients could vary, resulting in observed variations in individual electromyographic (EMG) patterns. Eleven cyclists were tested during a submaximal pedaling exercise and five all-out sprints. The effects of torque, maximal torque-velocity combination, and posture were studied. First, muscle synergies were extracted from each pedaling exercise independently using non-negative matrix factorization. Then, to cross-validate the results, muscle synergies were extracted from the entire data pooled across all conditions, and muscle synergy vectors extracted from the submaximal exercise were used to reconstruct EMG patterns of the five all-out sprints. Whatever the mechanical constraints, three muscle synergies accounted for the majority of variability [mean variance accounted for (VAF) = 93.3 ± 1.6%, VAF muscle > 82.5%] in the EMG signals of 11 lower limb muscles. In addition, there was a robust consistency in the muscle synergy vectors. This high similarity in the composition of the three extracted synergies was accompanied by slight adaptations in their activation coefficients in response to extreme changes in torque and posture. Thus, our results support the hypothesis that these muscle synergies reflect a neural control strategy, with only a few timing adjustments in their activation regarding the mechanical constraints.
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Santilli, Valter, Massimo A. Frascarelli, Marco Paoloni, Flaminia Frascarelli, Filippo Camerota, Luisa De Natale, and Fabio De Santis. "Peroneus Longus Muscle Activation Pattern during Gait Cycle in Athletes Affected by Functional Ankle Instability." American Journal of Sports Medicine 33, no. 8 (August 2005): 1183–87. http://dx.doi.org/10.1177/0363546504274147.
Full textAbstract:
Background Functional ankle instability is a clinical syndrome that may develop after acute lateral ankle sprain. Although several causes of this functional instability have been suggested, it is still unclear what the activation pattern of the peroneus longus muscle is in patients with functional ankle instability. Hypothesis Peroneus longus activation patterns differ in the injured side and the uninjured side in subjects with functional ankle instability. Study Design Descriptive laboratory study. Methods The authors examined 14 subjects with functional ankle instability by using surface electromyography during walking. Activation time of the peroneus longus muscle was expressed as a percentage of the stance phase of the gait cycle. Results A statistically significant decrease in peroneus longus muscle activity was found in the injured side compared with the uninjured side (22.8% ± 4.25% vs 37.6% ± 3.5%, respectively). Conclusions Results obtained in this study show a change in peroneus longus muscle activation time after injury. Independent of the origin of this change, which could only be surmised, the decrease in peroneus longus muscle activity may result in reduced protection against lateral sprains. Clinical Relevance The assessment of peroneus longus activation pattern during gait is useful to design an appropriate rehabilitation program in athletes suffering from functional ankle instability.
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Moore, Christopher A., Anne Smith, and Robert L. Ringel. "Task-Specific Organization of Activity in Human Jaw Muscles." Journal of Speech, Language, and Hearing Research 31, no. 4 (December 1988): 670–80. http://dx.doi.org/10.1044/jshr.3104.670.
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Coordination of jaw muscle activity for speech production sometimes has been modeled using nonspeech behaviors. This orientation has been especially true in representations of mandibular movement in which the synergy of jaw muscles for speech production has been suggested to be derived from the central pattern generator (CPG) for chewing. The present investigation compared the coordination of EMG activity in mandibular muscles over a range of speech and nonspeech tasks. Results of a cross-correlational analysis between EMG signals demonstrated that the muscle synergies of the mandibular system depend on task demands. Contrary to some of the models discussed, continuous speech production yielded activation patterns that were clearly not related to coordinative patterns generated by the chewing CPG.
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Cresci, S., L. D. Wright, J. A. Spratt, F. N. Briggs, and D. P. Kelly. "Activation of a novel metabolic gene regulatory pathway by chronic stimulation of skeletal muscle." American Journal of Physiology-Cell Physiology 270, no. 5 (May 1, 1996): C1413—C1420. http://dx.doi.org/10.1152/ajpcell.1996.270.5.c1413.
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To determine whether expression of a nuclear gene encoding a mitochondrial fatty acid oxidation enzyme is regulated in parallel with skeletal muscle fibre-type-specific energy substrate preference, expression of the gene encoding medium-chain acyl-CoA dehydrogenase (MCAD) was delineated in canine latissimus dorsi muscle subjected to chronic motor nerve stimulation. In predominantly fast-twitch canine latissimus dorsi muscle, MCAD mRNA levels were regulated by chronic stimulation in a biphasic pattern. During the 1st wk of stimulation, steady-state MCAD mRNA levels decreased to 50% of unstimulated levels. MCAD mRNA levels began to increase during the 3rd wk of stimulation to reach a level 3.0-fold higher than levels in unstimulated contralateral control muscle by day 70. Immunodetectable MCAD mRNA levels throughout the stimulation period. The temporal pattern and magnitude of MCAD mRNA accumulation in response to muscle stimulation was distinct from that of mRNAs encoding other enzymes known to be regulated by this stimulus, including glyceraldehyde phosphate dehydrogenase, citrate synthase, and sarcoplasmic reticulum Ca-ATPase, but paralleled the protein levels of the peroxisome proliferator-activated receptor (PPAR), an orphan member of the nuclear hormone receptor superfamily known to regulate genes encoding fatty acid oxidation enzymes in liver. The skeletal muscle expression pattern of PPAR was also similar to that of MCAD in unstimulated rat skeletal muscles with distinct fiber-type compositions. These results demonstrate that a nuclear gene encoding a mitochondrial beta-oxidation enzyme is dynamically regulated in a pattern that parallels skeletal muscle fiber-type-specific energy substrate utilization and implicate an orphan nuclear receptor transcription factor as a candidate transducer of this response.
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Schuermans, Joke, Damien Van Tiggelen, and Erik Witvrouw. "Prone Hip Extension Muscle Recruitment is Associated with Hamstring Injury Risk in Amateur Soccer." International Journal of Sports Medicine 38, no. 09 (July 13, 2017): 696–706. http://dx.doi.org/10.1055/s-0043-103016.
Full textAbstract:
Abstract‘Core stability’ is considered essential in rehabilitation and prevention. Particularly with respect to hamstring injury prevention, assessment and training of lumbo-pelvic control is thought to be key. However, supporting scientific evidence is lacking. To explore the importance of proximal neuromuscular function with regard to hamstring injury susceptibility, this study investigated the association between the Prone Hip Extension (PHE) muscle activation pattern and hamstring injury incidence in amateur soccer players. 60 healthy male soccer players underwent a comprehensive clinical examination, comprising a range of motion assessments and the investigation of the posterior chain muscle activation pattern during PHE. Subsequently, hamstring injury incidence was recorded prospectively throughout a 1.5-season monitoring period. Players who were injured presented a PHE activation pattern that differed significantly from those who did not. Contrary to the controls, hamstring activity onset was significantly delayed (p=0.018), resulting in a shifted activation sequence. Players were 8 times more likely to get injured if the hamstring muscles were activated after the lumbar erector spinae instead of vice versa (p=0.009). Assessment of muscle recruitment during PHE demonstrated to be useful in injury prediction, suggesting that neuromuscular coordination in the posterior chain influences hamstring injury vulnerability.
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Teulier, Caroline, Jennifer K. Sansom, Karin Muraszko, and Beverly D. Ulrich. "Longitudinal changes in muscle activity during infants' treadmill stepping." Journal of Neurophysiology 108, no. 3 (August 1, 2012): 853–62. http://dx.doi.org/10.1152/jn.01037.2011.
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Previous research has described kinetic characteristics of treadmill steps in very stable steppers, in cross-sectional designs. In this study we examined, longitudinally, muscle activation patterns during treadmill stepping, without practice, in 12 healthy infants at 1, 6, and 12 mo of age. We assessed lateral gastrocnemius, tibialis anterior, rectus femoris, and biceps femoris as infants stepped on a treadmill during twelve 20-s trials. Infants showed clear changes in kinematics, such as increased step frequency, increased heel contact at touch down, and more flat-footed contact at midstance. Electromyographic data showed high variability in muscle states (combinations), with high prevalence of all muscles active initially, reducing with age. Agonist-antagonist muscle coactivation also decreased as age increased. Probability analyses showed that across step cycles, the likelihood a muscle was on at any point tended to be <50%; lateral gastrocnemius was the exception, showing an adultlike pattern of probability across ages. In summary, over time, healthy infants produce a wide variety of muscle activation combinations and timings when generating stepping patterns on a treadmill, even if some levels of muscle control arose with time. However, the kinematic stability improved much more clearly than the underlying kinetic strategies. We conclude that although innate control of limb movement improves as infants grow, explore, and acquire functional movement, stepping on a treadmill is a novel and unpracticed one. Hence, developing stable underlying neural activations will only arise as functional practice ensues, similarly to that observed for other functional movements in infancy.
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Josephson, R. K. "Dissecting muscle power output." Journal of Experimental Biology 202, no. 23 (December 1, 1999): 3369–75. http://dx.doi.org/10.1242/jeb.202.23.3369.
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The primary determinants of muscle force throughout a shortening-lengthening cycle, and therefore of the net work done during the cycle, are (1) the shortening or lengthening velocity of the muscle and the force-velocity relationship for the muscle, (2) muscle length and the length-tension relationship for the muscle, and (3) the pattern of stimulation and the time course of muscle activation following stimulation. In addition to these primary factors, there are what are termed secondary determinants of force and work output, which arise from interactions between the primary determinants. The secondary determinants are length-dependent changes in the kinetics of muscle activation, and shortening deactivation, the extent of which depends on the work that has been done during the preceding shortening. The primary and secondary determinants of muscle force and work are illustrated with examples drawn from studies of crustacean muscles.
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Savelberg, Hans H. C. M., Ingrid G. L. Van de Port, and Paul J. B. Willems. "Body Configuration in Cycling Affects Muscle Recruitment and Movement Pattern." Journal of Applied Biomechanics 19, no. 4 (November 2003): 310–24. http://dx.doi.org/10.1123/jab.19.4.310.
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By manipulating trunk angle in ergometer cycling, we studied the effect of body configuration on muscle recruitment and joint kinematics. Changing trunk angle affects the length of muscles that span the hip joint. It is hypothesized that this affects the recruitment of the muscles directly involved, and as a consequence of affected joint torque distributions, also influences the recruitment of more distal muscles and the kinematics of distal joints. It was found that changing the trunk from an upright position to approximately 20 deg forward or backward affected muscle activation patterns and kinematics in the entire lower limb. The knee joint was the only joint not affected by manipulation of the lengths of hip joint muscles. Changes in trunk angle affected ankle and hip joint kinematics and the orientation of the thigh. A similar pattern has been demonstrated for muscle activity: Both the muscles that span the hip joint and those acting on the ankle joint were affected with respect to timing and amplitude of EMG. Moreover, it was found that the association between muscle activity and muscle length was adapted to manipulation of trunk angle. In all three conditions, most of the muscles that were considered displayed some eccentric activity. The ratio of eccentric to concentric activity changed with trunk angle. The present study showed that trunk angle influences muscle recruitment and (inter)muscular dynamics in the entire limb. As this will have consequences for the efficiency of cycling, body configuration should be a factor in bicycle design.