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Journal articles on the topic 'Locomotor system'
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1
Grillner, Sten, and Abdeljabbar El Manira. "Current Principles of Motor Control, with Special Reference to Vertebrate Locomotion." Physiological Reviews 100, no. 1 (January 1, 2020): 271–320. http://dx.doi.org/10.1152/physrev.00015.2019.
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The vertebrate control of locomotion involves all levels of the nervous system from cortex to the spinal cord. Here, we aim to cover all main aspects of this complex behavior, from the operation of the microcircuits in the spinal cord to the systems and behavioral levels and extend from mammalian locomotion to the basic undulatory movements of lamprey and fish. The cellular basis of propulsion represents the core of the control system, and it involves the spinal central pattern generator networks (CPGs) controlling the timing of different muscles, the sensory compensation for perturbations, and the brain stem command systems controlling the level of activity of the CPGs and the speed of locomotion. The forebrain and in particular the basal ganglia are involved in determining which motor programs should be recruited at a given point of time and can both initiate and stop locomotor activity. The propulsive control system needs to be integrated with the postural control system to maintain body orientation. Moreover, the locomotor movements need to be steered so that the subject approaches the goal of the locomotor episode, or avoids colliding with elements in the environment or simply escapes at high speed. These different aspects will all be covered in the review.
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Wannier, T., T. G. Deliagina, G. N. Orlovsky, and S. Grillner. "Differential Effects of the Reticulospinal System on Locomotion in Lamprey." Journal of Neurophysiology 80, no. 1 (July 1, 1998): 103–12. http://dx.doi.org/10.1152/jn.1998.80.1.103.
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Wannier, T., T. G. Deliagina, G. N. Orlovsky, and S. Grillner. Differential effects of the reticulospinal system on locomotion in lamprey. J. Neurophysiol. 80: 103–112, 1998. Specific effects of stimulating different parts of the reticulospinal (RS) system on the spinal locomotor pattern are described in lamprey. In the in vitro brain stem and spinal cord preparation, microstimulation in different areas of the reticular formation was performed by ejecting a small amount of d-glutamate from a micropipette. These areas were distributed over the four reticular nuclei of the brain stem: the mesencephalic reticular nucleus (MRN) and the anterior, middle and posterior rhombencephalic reticular nuclei (ARRN, MRRN, and PRRN, respectively). To prevent synaptic spread of excitation within the brain stem, the synaptic transmission was blocked by using a low Ca2+, high Mn2+ physiological saline in the brain stem pool. “Fictive” locomotion was evoked by applying N-methyl-d-aspartate (NMDA) to the spinal cord. Rhythmical discharges of motoneurons were recorded bilaterally in the midbody area, from the ventral roots that had been subdivided in dorsal and ventral branches, supplying the dorsal and ventral part of the myotome, respectively. Two major effects of brain stem stimulation were elicited: a change in the frequency of the locomotory rhythm and an induction of asymmetry (left/right, dorsal/ventral) in the segmental motor output. Approximately 50% of the stimulated sites evoked a change in locomotor frequency. In the PRRN almost all effective sites evoked an increase in frequency (10–50%). In the other nuclei, increase and decrease (10–30%) were observed equally frequently. Most of the stimulated sites (50–80%) in any reticular nucleus evoked asymmetry in the segmental motor output. Distortion of the segmental output symmetry was classified into eight categories by comparing the intensity of locomotor bursts in the dorsal and ventral branches of the two ventral roots, ipsilateral and contralateral to the stimulated side. These categories differed in the direction of the body flexion, which would be evoked during normal swimming: ipsilateral (I), contralateral (C), dorsal (D), ventral (V), ipsilateral and dorsal (ID), ipsilateral and ventral (IV), contralateral and dorsal (CD), and contralateral and ventral (CV). The different categories were not equally represented in each nucleus and across the nuclei. The most pronounced categories for each nucleus were as follow. In MRN: I (33%); ARRN: C (44%); MRRN: rostral part, I (36%) and caudal part, CV (42%); and PRRN: rostral part, I (40%) and caudal part, IV (35%). Other categories were also present but less common in each nucleus. To examine if the effects of brain stem stimulation were uniform along the spinal cord, recordings were performed from distal parts of the cord. Stimulation of a given point in the brain stem produced similar pattern of effects in 59% of cases and different patterns in 41% of cases. The main conclusion of the present study is that the proportion of RS neurons with different influences on the spinal locomotor network differs significantly among different parts of the reticular formation of the lamprey. The specificity of RS influences may represent a basis for modifications of the segmental locomotor output necessary for the control of equilibrium and steering during locomotion.
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Othayoth, Ratan, George Thoms, and Chen Li. "An energy landscape approach to locomotor transitions in complex 3D terrain." Proceedings of the National Academy of Sciences 117, no. 26 (June 15, 2020): 14987–95. http://dx.doi.org/10.1073/pnas.1918297117.
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Effective locomotion in nature happens by transitioning across multiple modes (e.g., walk, run, climb). Despite this, far more mechanistic understanding of terrestrial locomotion has been on how to generate and stabilize around near–steady-state movement in a single mode. We still know little about how locomotor transitions emerge from physical interaction with complex terrain. Consequently, robots largely rely on geometric maps to avoid obstacles, not traverse them. Recent studies revealed that locomotor transitions in complex three-dimensional (3D) terrain occur probabilistically via multiple pathways. Here, we show that an energy landscape approach elucidates the underlying physical principles. We discovered that locomotor transitions of animals and robots self-propelled through complex 3D terrain correspond to barrier-crossing transitions on a potential energy landscape. Locomotor modes are attracted to landscape basins separated by potential energy barriers. Kinetic energy fluctuation from oscillatory self-propulsion helps the system stochastically escape from one basin and reach another to make transitions. Escape is more likely toward lower barrier direction. These principles are surprisingly similar to those of near-equilibrium, microscopic systems. Analogous to free-energy landscapes for multipathway protein folding transitions, our energy landscape approach from first principles is the beginning of a statistical physics theory of multipathway locomotor transitions in complex terrain. This will not only help understand how the organization of animal behavior emerges from multiscale interactions between their neural and mechanical systems and the physical environment, but also guide robot design, control, and planning over the large, intractable locomotor-terrain parameter space to generate robust locomotor transitions through the real world.
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Nassar, P. N., A. C. Jackson, and D. R. Carrier. "Entraining the natural frequencies of running and breathing in guinea fowl (Numida meleagris)." Journal of Experimental Biology 204, no. 9 (May 1, 2001): 1641–51. http://dx.doi.org/10.1242/jeb.204.9.1641.
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Lung ventilation of tetrapods that synchronize their locomotory and ventilatory cycles during exercise could be economized if the resonant frequency of the respiratory system matched the animal's preferred step frequency. To test whether animals utilize this strategy, the input impedance of the respiratory system of five anesthetized, supine guinea fowl (Numida meleagris) was measured using a forced oscillation technique. The resonant frequency of the respiratory system was 7.12+/−0.27 Hz (N=5, mean +/− S.E.M.). No statistically significant difference was found between the resonant frequency of the respiratory system and the panting frequency used by guinea fowl at rest (6.67+/−0.16 Hz, N=11) or during treadmill locomotion (6.71+/−0.12 Hz, N=8) or to their preferred step frequency (6.73+/−0.09 Hz, N=7) (means +/− S.E.M.). These observations suggest (i) that, at rest and during exercise, panting guinea fowl maximize flow while expending minimal mechanical effort, and (ii) that natural selection has tuned the natural frequencies of the respiratory and locomotor systems to similar frequencies.
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Hao, Xin, Wenxing Ma, Chunbao Liu, Zhihui Qian, Luquan Ren, and Lei Ren. "Locomotor mechanism of Haplopelma hainanum based on energy conservation analysis." Biology Open 9, no. 12 (November 4, 2020): bio055301. http://dx.doi.org/10.1242/bio.055301.
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ABSTRACTSpiders use their special hydraulic system to achieve superior locomotor performance and high drive efficiency. To evaluate the variation in hydraulic joint angles and energy conversion during the hydraulic drive of spiders, kinematic data of Haplopelma hainanum were collected through a 3D motion capture and synchronization analysis system. Complete stride datasets in the speed range of 0.027 to 0.691 m s−1 were analyzed. Taking the tibia–metatarsu joint as an example, it was found that speed did not affect the angle variation range of the hydraulic joint. Based on the analysis of locomotor mechanics, a bouncing gait was mainly used by H. hainanum during terrestrial locomotion and their locomotor mechanism did not change with increasing speed. Because of the spiders’ hydraulic system, the mass-specific power per unit weight required to move the center of mass increased exponentially with increasing speed. The bouncing gait and the hydraulic system contributed to the lower transport cost at low speed, while the hydraulic system greatly increased the transport cost at high speed. The results of this study could provide a reference for the design of high-efficiency driving hydraulic systems of spider-like robots.
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Kowalski, Solange, Thierry Aubin, and Jean-René Martin. "Courtship song in Drosophila melanogaster: a differential effect on male–female locomotor activity." Canadian Journal of Zoology 82, no. 8 (August 1, 2004): 1258–66. http://dx.doi.org/10.1139/z04-102.
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The courtship song of male Drosophila melanogaster Meigen, 1830 is involved in species recognition and sexual stimulation. This signal is usually addressed to the female to reduce her locomotor activity, thereby facilitating copulation. However, no accurate quantification of her locomotion has been made. To examine the effect of courtship song on locomotor behaviour of both sexes, we used a video-tracking system that allowed for the quantification of two indicators of activity level: distance moved and movement duration. First, we showed that the broadcast of the courtship song alone produced no effect on female locomotion. Females reduced their locomotor activity only when acoustical stimulation was placed in a natural courtship context (i.e., in the presence of a male). This suggests that the sum of visual, tactile, acoustic, and chemical stimuli provided by the male may act together to trigger female receptivity. Second, our playback experiments showed a strong stimulating effect of courtship song (particularly of the pulse component) on the locomotor activity of isolated males, suggesting that this signal probably plays a role in male stimulation. Courtship song has an opposite effect on male/female locomotor activity in D. melanogaster.
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Capano, John G. "Reaction Forces and Rib Function During Locomotion in Snakes." Integrative and Comparative Biology 60, no. 1 (May 12, 2020): 215–31. http://dx.doi.org/10.1093/icb/icaa033.
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Synopsis Locomotion in most tetrapods involves coordinated efforts between appendicular and axial musculoskeletal systems, where interactions between the limbs and the ground generate vertical (GV), horizontal (GH), and mediolateral (GML) ground-reaction forces that are transmitted to the axial system. Snakes have a complete absence of external limbs and represent a fundamental shift from this perspective. The axial musculoskeletal system of snakes is their primary structure to exert, transmit, and resist all motive and reaction forces for propulsion. Their lack of limbs makes them particularly dependent on the mechanical interactions between their bodies and the environment to generate the net GH they need for forward locomotion. As organisms that locomote on their bellies, the forces that enable the various modes of snake locomotion involve two important structures: the integument and the ribs. Snakes use the integument to contact the substrate and produce a friction-reservoir that exceeds their muscle-induced propulsive forces through modulation of scale stiffness and orientation, enabling propulsion through variable environments. XROMM work and previous studies suggest that the serially repeated ribs of snakes change their cross-sectional body shape, deform to environmental irregularities, provide synergistic stabilization for other muscles, and differentially exert and transmit forces to control propulsion. The costovertebral joints of snakes have a biarticular morphology, relative to the unicapitate costovertebral joints of other squamates, that appears derived and not homologous with the ancestral bicapitate ribs of Amniota. Evidence suggests that the biarticular joints of snakes may function to buttress locomotor forces, similar to other amniotes, and provide a passive mechanism for resisting reaction forces during snake locomotion. Future comparisons with other limbless lizard taxa are necessary to tease apart the mechanics and mechanisms that produced the locomotor versatility observed within Serpentes.
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Contarino, Angelo, Françoise Dellu, George F. Koob, George W. Smith, Kuofen Lee, Wylie W. Vale, and Lisa H. Gold. "Dissociation of Locomotor Activation and Suppression of Food Intake Induced by CRF in CRFR1-Deficient Mice." Endocrinology 141, no. 7 (July 1, 2000): 2698–702. http://dx.doi.org/10.1210/endo.141.7.7653.
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ABSTRACT Corticotropin-releasing factor (CRF) systems are involved in locomotor and feeding behaviors. Two distinct CRF receptor subtypes, CRFR1 and CRFR2, are thought to mediate CRF actions in the central nervous system. However, the role for each receptor in locomotor activity and feeding remains to be determined. Using CRFR1 null mutant mice, the present study examined the functional significance of this receptor in ambulation and feeding. CRF treatment of wild-type mice resulted in increased levels of locomotion whereas no change was observed in CRFR1-deficient mice as compared to vehicle-treated mutant mice. In contrast, CRF decreased food-water intake in both wild type and CRFR1-deficient mice equally. These results support an important role for CRFR1 in mediating CRF-induced locomotor activation, whereas other receptor subtypes, likely CRFR2, may mediate the appetite-suppressing effects of CRF-like peptides.
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Wollheim, Frank A., and Henning Locht. "Introduction – Microorganisms and the locomotor system." Best Practice & Research Clinical Rheumatology 25, no. 3 (June 2011): 333–35. http://dx.doi.org/10.1016/j.berh.2011.06.002.
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Thörn Pérez, Carolina, Russell H. Hill, Abdeljabbar El Manira, and Sten Grillner. "Endocannabinoids Mediate Tachykinin-Induced Effects in the Lamprey Locomotor Network." Journal of Neurophysiology 102, no. 3 (September 2009): 1358–65. http://dx.doi.org/10.1152/jn.00294.2009.
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The spinal network underlying locomotion in lamprey is composed of excitatory and inhibitory interneurons mediating fast ionotropic action. In addition, several modulator systems are activated as locomotion is initiated, including the tachykinin system and the metabotropic glutamate receptor 1 (mGluR1), the latter operating partially via the endocannabinoid system. The effects of mGluR1 agonists and tachykinins resemble each other. Like mGluR1 agonists, the tachykinin substance P accelerates the burst rate and reduces the crossed inhibition in an activity-dependent fashion. The present study therefore explores whether tachykinins also use the endocannabinoid system to modulate the locomotor frequency. By monitoring fictive locomotion, we were able to compare the facilitatory effects exerted by applying substance P (1 μM, 20 min), on the burst frequency before and during application of the endocannabinoid CB1 receptor antagonist AM251 (2–5 μM). By using two different lamprey species, we showed that the response to substance P on the burst frequency is significantly reduced during the application of AM251. To examine whether endocannabinoids are involved in the substance P–mediated modulation of reciprocal inhibition, the commissural axons were stimulated, while recording intracellularly from motoneurons. We compare the effect of substance P on the amplitude of the contralateral compound glycinergic inhibitory postsynaptic potential (IPSP) in control and in the presence of AM251. The blockade of CB1 receptors reduced the substance P–mediated decrease in the amplitude by 29%. The present findings suggest that the effects of substance P on the increase in the locomotor burst frequency and depression of IPSPs are mediated partially via release of endocannabinoids acting through CB1 receptors.
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Rossignol, Serge, Réjean Dubuc, and Jean-Pierre Gossard. "Dynamic Sensorimotor Interactions in Locomotion." Physiological Reviews 86, no. 1 (January 2006): 89–154. http://dx.doi.org/10.1152/physrev.00028.2005.
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Locomotion results from intricate dynamic interactions between a central program and feedback mechanisms. The central program relies fundamentally on a genetically determined spinal circuitry (central pattern generator) capable of generating the basic locomotor pattern and on various descending pathways that can trigger, stop, and steer locomotion. The feedback originates from muscles and skin afferents as well as from special senses (vision, audition, vestibular) and dynamically adapts the locomotor pattern to the requirements of the environment. The dynamic interactions are ensured by modulating transmission in locomotor pathways in a state- and phase-dependent manner. For instance, proprioceptive inputs from extensors can, during stance, adjust the timing and amplitude of muscle activities of the limbs to the speed of locomotion but be silenced during the opposite phase of the cycle. Similarly, skin afferents participate predominantly in the correction of limb and foot placement during stance on uneven terrain, but skin stimuli can evoke different types of responses depending on when they occur within the step cycle. Similarly, stimulation of descending pathways may affect the locomotor pattern in only certain phases of the step cycle. Section ii reviews dynamic sensorimotor interactions mainly through spinal pathways. Section iii describes how similar sensory inputs from the spinal or supraspinal levels can modify locomotion through descending pathways. The sensorimotor interactions occur obviously at several levels of the nervous system. Section iv summarizes presynaptic, interneuronal, and motoneuronal mechanisms that are common at these various levels. Together these mechanisms contribute to the continuous dynamic adjustment of sensorimotor interactions, ensuring that the central program and feedback mechanisms are congruous during locomotion.
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Lees, John J., Robert L. Nudds, Lars P. Folkow, Karl-Arne Stokkan, and Jonathan R. Codd. "Understanding sex differences in the cost of terrestrial locomotion." Proceedings of the Royal Society B: Biological Sciences 279, no. 1729 (August 17, 2011): 826–32. http://dx.doi.org/10.1098/rspb.2011.1334.
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Little is known regarding the physiological consequences of the behavioural and morphological differences that result from sexual selection in birds. Male and female Svalbard rock ptarmigans ( Lagopus muta hyperborea ) exhibit distinctive behavioural differences during the breeding season. In particular, males continuously compete for and defend territories in order to breed successfully, placing large demands on their locomotor system. Here, we demonstrate that male birds have improved locomotor performance compared with females, showing both a lower cost of locomotion (CoL) and a higher top speed. We propose that the observed sex differences in locomotor capability may be due to sexual selection for improved male performance. While the mechanisms underlying these energetic differences are unclear, future studies should be wary when pooling male and female data.
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Yamaguchi, Hiroaki. "Control of A New Type of Undulatory Wheeled Locomotor: A Trident Steering Walker Based on Chained Form." Journal of Robotics and Mechatronics 21, no. 4 (August 20, 2009): 541–53. http://dx.doi.org/10.20965/jrm.2009.p0541.
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This paper introduces and describes a new type of undulatory wheeled locomotor, which we refer to as a “trident steering walker.” The wheeled locomotor is a nonholonomic mechanical system, which consists of an equilateral triangular base, three joints, three links and four steering systems. The equilateral triangular base has a steering system at its center of mass. At each apex of the base is a joint which connects the base and a link. The link has a steering system at its midpoint. The wheeled locomotor transforms driving the three joints into its movement by operating the four steering systems. This means that the wheeled locomotor achieves undulatory locomotion in which changes in its own shape are transformed into its net displacement. We assume that there is a virtual joint at the end of the first link. The virtual joint connects the first link and a virtual link which has a virtual axle at its midpoint and a virtual steering system at its end. We prove that, by assuming the presence of such virtual mechanical elements, it is possible to convert the kinematical equation of the trident steering walker into five-chain, single-generator chained form in a mathematical framework, differential geometry. Based on chained form, we derive a path following feedback control method which causes the trident steering walker to follow a straight path. We also define a performance index of propulsion of the trident steering walker to design its control parameters. The validity of the mechanical design of the trident steering walker, the conversion of its kinematical equation into chained form, the straight path following feedback control method, and the design of the control parameters reflecting the performance index of propulsion has been verified by computer simulations.
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Dominick, O. S., and J. W. Truman. "The physiology of wandering behaviour in Manduca sexta. III. Organization of wandering behaviour in the larval nervous system." Journal of Experimental Biology 121, no. 1 (March 1, 1986): 115–32. http://dx.doi.org/10.1242/jeb.121.1.115.
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The locomotor patterns typical of wandering behaviour were studied electromyographically in abdominal segments of freely moving larvae of Manduca sexta. Crawling locomotion consisted of stereotyped, anteriorly-directed, peristaltic waves of intersegmental muscle contraction. During burrowing the intersegmental muscles of all abdominal segments contracted simultaneously for several consecutive cycles and then performed a single bout of the crawling pattern. Sensory inputs determined which motor patterns were used and how they were modified. Local sensory inputs could modify patterns in the specific segments affected. The neural circuitry that was required to generate the peristaltic and bracing patterns was repeated among the thoracic and abdominal ganglia, and normally wa activated by the suboesophageal ganglion (SEG) and brain. In the absence of connections with the SEG and brain the segmental motor pattern generators could be activated by strong sensory stimuli. When the thoracic and abdominal segments lacked connections with the SEG, spontaneous movements were infrequent prior to wandering, but increased markedly at wandering or following 20-hydroxyecdysone (20-HE) infusion. Prior to wandering the SEG drives spontaneous locomotion in debrained larvae, but this function disappears in wandering larvae, or following 20-HE infusion. Prior to wandering the brain exerted a net inhibitory influence on locomotion. Removal of the medial region of the brain abolished this inhibition, resulting in strong, continuous locomotion which was driven by the lateral region of the brain. This lateral excitatory function of the brain was not altered by 20-HE infusion prior to wandering, nor did it change with the appearance of wandering behaviour. We conclude that the locomotor patterns used during wandering are produced by pattern generators in the segmental ganglia and are modified by sensory information. The circuitry responsible for activating these motor pattern generators is associated with the SEG, and is under the control of the brain. The brain exerts a net inhibitory influence prior to wandering, which becomes excitatory during wandering. Ecdysteroids appear to alter locomotor function by acting at various levels including the segmental ganglia, the SEG and the brain. A model is advanced describing this effect.
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Higham, Timothy E., Aleksandra V. Birn-Jeffery, Clint E. Collins, C. Darrin Hulsey, and Anthony P. Russell. "Adaptive simplification and the evolution of gecko locomotion: Morphological and biomechanical consequences of losing adhesion." Proceedings of the National Academy of Sciences 112, no. 3 (December 29, 2014): 809–14. http://dx.doi.org/10.1073/pnas.1418979112.
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Innovations permit the diversification of lineages, but they may also impose functional constraints on behaviors such as locomotion. Thus, it is not surprising that secondary simplification of novel locomotory traits has occurred several times among vertebrates and could potentially lead to exceptional divergence when constraints are relaxed. For example, the gecko adhesive system is a remarkable innovation that permits locomotion on surfaces unavailable to other animals, but has been lost or simplified in species that have reverted to a terrestrial lifestyle. We examined the functional and morphological consequences of this adaptive simplification in the Pachydactylus radiation of geckos, which exhibits multiple unambiguous losses or bouts of simplification of the adhesive system. We found that the rates of morphological and 3D locomotor kinematic evolution are elevated in those species that have simplified or lost adhesive capabilities. This finding suggests that the constraints associated with adhesion have been circumvented, permitting these species to either run faster or burrow. The association between a terrestrial lifestyle and the loss/reduction of adhesion suggests a direct link between morphology, biomechanics, and ecology.
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Rogers, Chris W., and Keren E. Dittmer. "Does Juvenile Play Programme the Equine Musculoskeletal System?" Animals 9, no. 9 (September 3, 2019): 646. http://dx.doi.org/10.3390/ani9090646.
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In mammals, play behaviour appears innate and, because of this, may provide insight into the frequency and intensity of load that is required to stimulate positive musculoskeletal development. The objective of this review was to explore the interaction between play and tissue (bone) development at a molecular through to whole-animal level, with specific focus on the horse as a model. The basis of our understanding of the response of bone to loading is the mechanostat theorem. This assumes that at a tissue level, bone attempts to keep localised strain within the physiological range of 1500–2500 microstrain. Loads above this range result in a modelling response to reduce strain, and strain below this threshold results in remodelling to maintain the localised physiological range. In foals, locomotor play is dramatic and vigorous, with cumulative increases in both intensity and complexity. Based on published literature describing locomotor play in foals and the microstrain at different gaits in the horse, it was proposed that locomotor play in foal aligns with the mechanostat theorem in both the magnitude and frequency of load cycles applied. The cumulative increases in the complexity and intensity of locomotor play as the foal develops, in turn, ensure the strain rates associated with play remain above the local physiological range and promote material and architectural changes in the distal limb bones. Thus, spontaneous locomotor play may be vital to ensure optimal bone development in the horse. Modern management systems need to provide appropriate opportunities for foals to perform spontaneous locomotor play to optimise bone development and reduce the risk of future musculoskeletal injury later in life.
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Bedford, T. G., P. K. Loi, and C. C. Crandall. "A model of dynamic exercise: the decerebrate rat locomotor preparation." Journal of Applied Physiology 72, no. 1 (January 1, 1992): 121–27. http://dx.doi.org/10.1152/jappl.1992.72.1.121.
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The purpose of this study was to develop a dynamic exercise model in the rat that could be used to study central nervous system control of the cardiovascular system. Rats of both sexes were decerebrated under halothane anesthesia and prepared for induced locomotion on a freely turning wheel. Electrical stimulation of the mesencephalic locomotor region (MLR) elicited locomotion at different speeds and gait patterns and increased heart rate and blood pressure. Two maneuvers were performed to illustrate the potential use of the preparation. The first maneuver consisted of muscular paralysis, which prevents excitation of muscle mechanoreceptors and chemoreceptors resulting from exercise. MLR stimulation still increased blood pressure. The second maneuver was performed to determine whether the blood pressure response obtained during paralysis was an artifact of electrical stimulation of the MLR. After microinjection of gamma-aminobutyric acid into the MLR, electrical current thresholds for blood pressure and locomotion increased in parallel. gamma-Aminobutyric acid injection also reduced the pressor response to suprathreshold electrical stimulation by 76%. The injection results suggest that electrical stimulation of the MLR activates cells rather than fibers of passage. The blood pressure response of the exercise model is probably not an artifact of stimulation. The decerebrate rat locomotor preparation should offer another approach to investigate difficult problems in exercise physiology.
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Bjelle, A. "Ageing and Disorders of The Locomotor System." Scandinavian Journal of Rheumatology 18, sup82 (January 1989): 3–12. http://dx.doi.org/10.3109/03009748909101463.
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Mellerowicz, H., E. Stelling, and A. Kefenbaum. "Diagnostic ultrasound in the athlete's locomotor system." British Journal of Sports Medicine 24, no. 1 (March 1, 1990): 31–39. http://dx.doi.org/10.1136/bjsm.24.1.31.
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Neeck, G. "Chronic pain syndromes of the locomotor system." Zeitschrift für Rheumatologie 60, no. 6 (December 2001): 403. http://dx.doi.org/10.1007/pl00007332.
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Saitoh, Kazuya, Ariane Ménard, and Sten Grillner. "Tectal Control of Locomotion, Steering, and Eye Movements in Lamprey." Journal of Neurophysiology 97, no. 4 (April 2007): 3093–108. http://dx.doi.org/10.1152/jn.00639.2006.
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The intrinsic function of the brain stem–spinal cord networks eliciting the locomotor synergy is well described in the lamprey—a vertebrate model system. This study addresses the role of tectum in integrating eye, body orientation, and locomotor movements as in steering and goal-directed behavior. Electrical stimuli were applied to different areas within the optic tectum in head-restrained semi-intact lampreys ( n = 40). Motions of the eyes and body were recorded simultaneously (videotaped). Brief pulse trains (<0.5 s) elicited only eye movements, but with longer stimuli (>0.5 s) lateral bending movements of the body (orientation movements) were added, and with even longer stimuli locomotor movements were initiated. Depending on the tectal area stimulated, four characteristic response patterns were observed. In a lateral area conjugate horizontal eye movements combined with lateral bending movements of the body and locomotor movements were elicited, depending on stimulus duration. The amplitude of the eye movement and bending movements was site specific within this region. In a rostromedial area, bilateral downward vertical eye movements occurred. In a caudomedial tectal area, large-amplitude undulatory body movements akin to struggling behavior were elicited, combined with large-amplitude eye movements that were antiphasic to the body movements. The alternating eye movements were not dependent on vestibuloocular reflexes. Finally, in a caudolateral area locomotor movements without eye or bending movements could be elicited. These results show that tectum can provide integrated motor responses of eye, body orientation, and locomotion of the type that would be required in goal-directed locomotion.
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Bury, Stanisław, Bartosz Borczyk, and Tomasz Skawiński. "Ventral scale width in snakes depends on habitat but not hunting strategy." Biological Journal of the Linnean Society 128, no. 4 (October 9, 2019): 987–93. http://dx.doi.org/10.1093/biolinnean/blz116.
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Abstract Environment and lifestyle induce substantial variation in the mechanisms of locomotion in vertebrates. A spectrum of adaptations related to locomotion is also present in limbless taxa, especially snakes, which have radiated successfully into a wide range of habitats. The majority of studies concerning habitat-driven variation in locomotor mechanisms of snakes have focused on the musculoskeletal system. Far less recognized is the variation in the morphology of ventral scales, which are another pivotal component of the locomotor system in snakes. Here, we investigated patterns of interspecific variation in the width of ventral scales in terms of lifestyle (hunting mode) and habitat occupied in 55 species of snakes belonging to eight families. We found that increasing terrestriality was associated with enlarged ventral scales. Reduction instead of maintenance of the width of ventral scales was observed in aquatic species, suggesting that wide ventral scales set constraints on aquatic locomotion. In terrestrial species, no significant differences were observed in terms of arboreality or hunting mode, which suggests overall optimization in the size of ventral scales towards terrestrial locomotion. Association between the width of ventral scales and locomotion can result in a habitat-dependent costs of abnormalities in ventral scale morphology, commonly observed in snakes.
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Alexander, M. Scott, Brent W. G. Flodin, and Daniel S. Marigold. "Prism adaptation and generalization during visually guided locomotor tasks." Journal of Neurophysiology 106, no. 2 (August 2011): 860–71. http://dx.doi.org/10.1152/jn.01040.2010.
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The ability of individuals to adapt locomotion to constraints associated with the complex environments normally encountered in everyday life is paramount for survival. Here, we tested the ability of 24 healthy young adults to adapt to a rightward prism shift (∼11.3°) while either walking and stepping to targets (i.e., precision stepping task) or stepping over an obstacle (i.e., obstacle avoidance task). We subsequently tested for generalization to the other locomotor task. In the precision stepping task, we determined the lateral end-point error of foot placement from the targets. In the obstacle avoidance task, we determined toe clearance and lateral foot placement distance from the obstacle before and after stepping over the obstacle. We found large, rightward deviations in foot placement on initial exposure to prisms in both tasks. The majority of measures demonstrated adaptation over repeated trials, and adaptation rates were dependent mainly on the task. On removal of the prisms, we observed negative aftereffects for measures of both tasks. Additionally, we found a unilateral symmetric generalization pattern in that the left, but not the right, lower limb indicated generalization across the 2 locomotor tasks. These results indicate that the nervous system is capable of rapidly adapting to a visuomotor mismatch during visually demanding locomotor tasks and that the prism-induced adaptation can, at least partially, generalize across these tasks. The results also support the notion that the nervous system utilizes an internal model for the control of visually guided locomotion.
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LEE, DONG RYUL, YOON KYUM SHIN, JI-HO PARK, and JOSHUA HYUN YOU. "CONCURRENT VALIDITY AND TEST-RETEST RELIABILITY OF THE WALKBOT-K SYSTEM FOR ROBOTIC GAIT TRAINING." Journal of Mechanics in Medicine and Biology 16, no. 08 (November 25, 2016): 1640029. http://dx.doi.org/10.1142/s0219519416400297.
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While the Walkbot-K robotic-assisted gait training systems have rapidly gained widespread acceptance for pediatric locomotor training in children with cerebral palsy, the validity and reliability for the Walkbot-K system have not been well established. The aim of this study is to investigate the validity and test-retest reliability of the innovative exoskeletal Walkbot-K system which is designed to help the active development and learning of fundamental locomotor skills in children with locomotor impairments. The electrogoniometer was used concurrently to compare the sagittal kinematic angular displacement data with that of the Walkbot-K system as a reference standard measure. Neuromechanical data obtained from kinematic measurement produced an excellent validity ([Formula: see text]). The test-retest reliability for kinematic knee angle data showed a remarkable consistency ([Formula: see text]). This study provides the first compelling evidence of the children’s robotic gait-assisted Walkbot-K system’s validity and reliability, indicating that the system is a highly valid and reliable robotic-assisted gait training system to evaluate and treat locomotor dysfunction.
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Zaman, V., Z. Li, L. Middaugh, S. Ramamoorthy, B. Rohrer, M. E. Nelson, A. C. Tomac, B. J. Hoffer, G. A. Gerhardt, and A. Ch Granholm. "The Noradrenergic System of Aged GDNF Heterozygous Mice." Cell Transplantation 12, no. 3 (April 2003): 291–303. http://dx.doi.org/10.3727/000000003108746740.
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Glial cell line-derived neurotrophic factor (GDNF) is a trophic factor for noradrenergic (NE) neurons of the pontine nucleus locus coeruleus (LC). Decreased function of the LC-NE neurons has been found during normal aging and in neurodegenerative disorders. We have previously shown that GDNF participates in the differentiation of LC-NE neurons during development. However, the continued role of GDNF for LC-NE neurons during maturation and aging has not been addressed. We examined alterations in aged mice that were heterozygous for the GDNF gene (Gdnf+/–). Wild-type (Gdnf+/+) and Gdnf+/– mice (18 months old) were tested for locomotor activity and brain tissues were collected for measuring norepinephrine levels and uptake, as well as for morphological analysis. Spontaneous locomotion was reduced in Gdnf+/– mice in comparison with Gdnf+/+ mice. The reduced locomotor activity of Gdnf +/– mice was accompanied by reductions in NE transporter activity in the cerebellum and brain stem as well as decreased norepinephrine tissue levels in the LC. Tyrosine hydroxylase (TH) immunostaining demonstrated morphological alterations of LC-NE cell bodies and abnormal TH-positive fibers in the hippocampus, cerebellum, and frontal cortex of Gdnf+/– mice. These findings suggest that the LC-NE system of Gdnf+/– mice is impaired and suggest that GDNF plays an important role in continued maintenance of this neuronal system throughout life.
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Eigen, Lennart, and John A. Nyakatura. "Architectural properties of the musculoskeletal system in the shoulder of two callitrichid primate species derived from virtual dissection." Primates 62, no. 5 (June 28, 2021): 827–43. http://dx.doi.org/10.1007/s10329-021-00917-7.
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AbstractCallitrichidae are small, arboreal New World primates that utilize a variety of locomotor behaviors including trunk-to-trunk leaping (TTL) and horizontal locomotion which involve differential functional demands. Little is known about the relationship between the preferred locomotor behavior and musculoskeletal architecture of these primates. In this study, we compared the musculoskeletal architecture of selected shoulder muscles in two cadavers each of the trunk-to-trunk leaper Cebuella pygmaea and the mainly pronograde quadrupedally moving Saguinus imperator subgrisescens. Contrast-enhanced microfocus computed tomography (µCT) was used to virtually dissect the cadavers, produce muscle maps, and create 3D reconstructions for an image-based analysis of the muscles. Muscle lengths, muscle volumes, and osteological muscle moment arms were measured, and the anatomical cross-sectional areas (ACSA) were calculated. We expected the muscles of the forelimb of S. imperator to be larger in volume and to be relatively shorter with a larger ACSA due to a higher demand for powerful extension in the forelimbs of this horizontally locomoting species. For C. pygmaea, we expected relatively larger moment arms for the triceps brachii, supraspinatus, infraspinatus and subscapularis, as larger moment arms present an advantage for extensive vertical clinging on the trunk. The muscles of S. imperator were relatively larger in volume than in C. pygmaea and had a relatively larger ACSA. Thus, the shoulder muscles of S. imperator were suited to generate relatively larger forces than those of C. pygmaea. Contrary to our expectations, there were only slight differences between species in regard to muscle lengths and moment arms, which suggests that these properties are not dependent on the preferred locomotor mode. The study of this limited dataset demonstrates that some but not all properties of the musculoskeletal architecture reflect the preferred locomotor behavior in the two species of Callitrichidae examined.
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Schmitt, David E., Russell H. Hill, and Sten Grillner. "The Spinal GABAergic System Is a Strong Modulator of Burst Frequency in the Lamprey Locomotor Network." Journal of Neurophysiology 92, no. 4 (October 2004): 2357–67. http://dx.doi.org/10.1152/jn.00233.2004.
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The spinal network coordinating locomotion is comprised of a core of glutamate and glycine interneurons. This network is modulated by several transmitter systems including spinal GABA interneurons. The purpose of this study is to explore the contribution of GABAergic neurons to the regulation of locomotor burst frequency in the lamprey model. Using gabazine, a competitive GABAA antagonist more specific than bicuculline, the goal was to provide a detailed analysis of the influence of an endogenous activation of GABAA receptors on fictive locomotion, as well as their possible interaction with GABAB and involvement of GABAC receptors. During N-methyl-d-aspartate (NMDA)-induced fictive locomotion (ventral root recordings in the isolated spinal cord), gabazine (0.1–100 μM) significantly increased the burst rate up to twofold, without changes in regularity or “burst quality.” Gabazine had a proportionately greater effect at higher initial burst rates. Picrotoxin (1–7.5 μM), a less selective GABAA antagonist, also produced a pronounced increase in frequency, but at higher concentrations, the rhythm deteriorated, likely due to the unspecific effects on glycine receptors. The selective GABAB antagonist CGP55845 also increased the frequency, and this effect was markedly enhanced when combined with the GABAA antagonist gabazine. The GABAC antagonist (1,2,5,6-tetrahydropyridine-4-yl)methylphosphinic acid (TPMPA) had no effect on locomotor bursting. Thus the spinal GABA system does play a prominent role in burst frequency regulation in that it reduces the burst frequency by ≤50%, presumably due to presynaptic and soma-dendritic effects documented previously. It is not required for burst generation, but acts as a powerful modulator.
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Tegner, J., T. Matsushima, A. el Manira, and S. Grillner. "The spinal GABA system modulates burst frequency and intersegmental coordination in the lamprey: differential effects of GABAA and GABAB receptors." Journal of Neurophysiology 69, no. 3 (March 1, 1993): 647–57. http://dx.doi.org/10.1152/jn.1993.69.3.647.
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1. The effect of spinal GABAergic neurons on the segmental neuronal network generating locomotion has been analyzed in the lamprey spinal cord in vitro. It is shown that gamma-aminobutyric acid (GABA)A- and GABAB-mediated effects influence the burst frequency and the intersegmental coordination and that the GABA system is active during normal locomotor activity. 2. Fictive locomotor activity was induced by superfusing the spinal cord with a Ringer solution containing N-methyl-D-aspartate (NMDA, 150 microM). The efferent locomotor activity was recorded by suction electrodes from the ventral roots or intracellularly from interneurons or motoneurons. If a GABA uptake blocker was added to the perfusate, the burst rate decreased. This effect was counteracted by GABAB receptor blockade by phaclofen or 2-(OH)-saclofen. If instead a GABAB receptor agonist (baclofen) was added during fictive locomotion, a depression of the burst rate occurred. It was concluded that a GABAB receptor activation due to an endogenous release of GABA caused a depression of the burst activity with a maintained well-coordinated locomotor activity. 3. If a GABAA receptor antagonist (bicuculline) is applied during fictive locomotion elicited by NMDA, a certain increase of the burst rate occurred. Conversely, if a selective GABAA agonist (muscimol) was administered, the burst rate decreased. Similarly, if the GABAA receptor activity was potentiated by activation of a benzodiazepine site by diazepam, the burst rate was reduced. If, however the GABAergic effect was first enhanced by an uptake blocker (nipecotic acid), an administration of a GABAA antagonist (bicuculline) increased the burst rate, but in addition, the burst pattern became less regular with recurrent shorter periods without clear reciprocal burst activity. The GABAA receptor activity appears important for the rate control and for permitting a regular burst pattern. 4. The intersegmental coordination in the lamprey is characterized by a rostrocaudal constant phase lag of approximately 1% of the cycle duration between the activation of consecutive segments during forward swimming. This rostrocaudal phase lag can be reversed during backward swimming, which can be induced also experimentally in the isolated spinal cord by providing a higher excitability to the caudal segments. In a split-bath configuration, a GABA uptake blocker or a GABAB agonist was administered to the rostral part of the spinal cord, which caused a reversal of the phase lag as during backward swimming. If GABAA receptors were blocked under similar conditions, the intersegmental coordination became irregular. It is concluded that an increased GABA activity in a spinal cord region can modify the intersegmental coordination.(ABSTRACT TRUNCATED AT 400 WORDS)
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Cowley, Kristine C., Eugene Zaporozhets, Raed A. Joundi, and Brian J. Schmidt. "Contribution of Commissural Projections to Bulbospinal Activation of Locomotion in the In Vitro Neonatal Rat Spinal Cord." Journal of Neurophysiology 101, no. 3 (March 2009): 1171–78. http://dx.doi.org/10.1152/jn.91212.2008.
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Commissural projections are required for left-right coordination during locomotion. However, their role, if any, in rhythm production is unknown. This study uses the neonatal rat in vitro brain stem–spinal cord model to examine the rostrocaudal distribution of locomotor-related commissural projections and study whether commissural connections are needed for the generation of hindlimb rhythmic activity in response to electrical stimulation of the brain stem. Midsagittal lesions were made at a wide range of rostrocaudal levels. Locomotor-like activity persisted in some preparations despite midsagittal lesions extending from C1 to the mid-L1 level or from the conus medullaris to the T12/13 junction. In some preparations, midsagittal lesions throughout the entire spinal cord had no effect on locomotor-like activity if two or three contiguous segments remained intact. Those bridging segments had to include the T13 and/or L1 levels. These observations suggested that commissural projections in the thoracolumbar junction region were critical. However, locomotor-like activity was also elicited in preparations with limited midsagittal lesions focused on the thoracolumbar junction (T12 through L1 or L2 inclusive). In other experiments, locomotor-like activity was evoked by bath-applied 5-hydroxytryptamine (5-HT) and N-methyl-d-aspartate (NMDA). Appropriate side-to-side coordination was observed, even when only one segment remained bilaterally intact. Commissural projections traversing the thoracolumbar junction region were most effective. In combination, these results suggest that locomotor-related commissural projections are redundantly distributed along a bi-directional gradient that centers on the thoracolumbar junction. This commissural system not only provides a robust left-right coordinating mechanism but also supports locomotor rhythm generation in response to brain stem stimulation.
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Donelson, Nathan C., Richa Dixit, Israel Pichardo-Casas, Eva Y. Chiu, Robert T. Ohman, Justin B. Slawson, Mason Klein, Tudor A. Fulga, David Van Vactor, and Leslie C. Griffith. "MicroRNAs Regulate Multiple Aspects of Locomotor Behavior in Drosophila." G3: Genes|Genomes|Genetics 10, no. 1 (November 6, 2019): 43–55. http://dx.doi.org/10.1534/g3.119.400793.
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Locomotion is an ancient and fundamental output of the nervous system required for animals to perform many other complex behaviors. Although the formation of motor circuits is known to be under developmental control of transcriptional mechanisms that define the fates and connectivity of the many neurons, glia and muscle constituents of these circuits, relatively little is known about the role of post-transcriptional regulation of locomotor behavior. MicroRNAs have emerged as a potentially rich source of modulators for neural development and function. In order to define the microRNAs required for normal locomotion in Drosophila melanogaster, we utilized a set of transgenic Gal4-dependent competitive inhibitors (microRNA sponges, or miR-SPs) to functionally assess ca. 140 high-confidence Drosophila microRNAs using automated quantitative movement tracking systems followed by multiparametric analysis. Using ubiquitous expression of miR-SP constructs, we identified a large number of microRNAs that modulate aspects of normal baseline adult locomotion. Addition of temperature-dependent Gal80 to identify microRNAs that act during adulthood revealed that the majority of these microRNAs play developmental roles. Comparison of ubiquitous and neural-specific miR-SP expression suggests that most of these microRNAs function within the nervous system. Parallel analyses of spontaneous locomotion in adults and in larvae also reveal that very few of the microRNAs required in the adult overlap with those that control the behavior of larval motor circuits. These screens suggest that a rich regulatory landscape underlies the formation and function of motor circuits and that many of these mechanisms are stage and/or parameter-specific.
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Liang, Jing Nong, and David A. Brown. "Impaired foot-force direction regulation during postural loaded locomotion in individuals poststroke." Journal of Neurophysiology 110, no. 2 (July 15, 2013): 378–86. http://dx.doi.org/10.1152/jn.00005.2013.
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Following stroke, hemiparesis results in impaired motor control. Specifically, inappropriate direction of foot-forces during locomotion has been reported. In our previous study ( Liang and Brown 2011 ) that examined poststroke foot-force direction during a seated, supported locomotor task, we observed that foot-force control capabilities were preserved poststroke. In this current study, we sought to better understand the mechanisms underlying the interaction of locomotor and postural control as an interactive mechanism that might interfere, poststroke, with appropriate foot-force generation. We designed an experiment in which participants performed biomechanically controlled locomotor tasks, under posturally challenged pedaling conditions while they generated mechanical output that was comparable to pedaling conditions without postural challenge, thus allowing us to monitor the strategies that the nervous system adopts when postural conditions were manipulated. We hypothesized that, with postural influence, individuals poststroke would generate inappropriate shear forces accompanied by inappropriate changes to muscle activity patterns when performing a mechanically controlled locomotor task, and would be exaggerated with increased postural loading. Sixteen individuals with chronic poststroke hemiparesis and 14 age-similar nonimpaired controls pedaled on a cycle ergometer under 1) seated supported and 2) nonseated postural loaded pedaling conditions, generating matched pedal force outputs of two effort levels. When we compared postural influence with seated pedaling, we observed increased magnitudes of forward-directed shear forces in the paretic legs associated with increased magnitude of leg extensor muscle activity, but not in controls. These findings provide evidence to support a model that describes independent controllers for posture and locomotion, but that the interaction between the two controllers is impaired poststroke.
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Gouwanda, Darwin, and S. M. N. Arosha Senanayake. "Non-Linear Time Analysis to Estimate Gait Stability Using Wearable Gyroscopes Network." Journal of Robotics and Mechatronics 24, no. 4 (August 20, 2012): 576–84. http://dx.doi.org/10.20965/jrm.2012.p0576.
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Gait stability is very important in assessing human locomotion. Maximum Lyapunov exponent (λ*) has been widely reported to be closely related to the ability of the human locomotor system in maintaining walking balance. Most literature reports have, however, utilized optical motion capture systems, electrogoniometers and accelerometers to determine λ*. This paper introduces the use of wearable wireless gyroscopes for estimating gait stability. An experimental study was conducted to validate the efficacy of this approach. Its outcome was consistent and comparable to results obtained from conventional approaches.
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Farley, Alistair, Ella McLafferty, and Charles Hendry. "The anatomy and physiology of the locomotor system." Nursing Standard 27, no. 7 (October 17, 2012): 35–43. http://dx.doi.org/10.7748/ns2012.10.27.7.35.c9358.
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Farley, Alistair, Ella McLafferty, and Charles Hendry. "The anatomy and physiology of the locomotor system." Nursing Standard 27, no. 7 (October 17, 2012): 35–43. http://dx.doi.org/10.7748/ns.27.7.35.s56.
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Nikolić, V., M. Hudec, M. Marotti, A. Jo, and A. Lovrić. "Three-dimensional structural analysis of the locomotor system." Journal of Biomechanics 18, no. 7 (January 1985): 533. http://dx.doi.org/10.1016/0021-9290(85)90739-0.
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Luo, Jingshun, Wei Liu, Fen Feng, and Linxi Chen. "Apelin/APJ system: A novel therapeutic target for locomotor system diseases." European Journal of Pharmacology 906 (September 2021): 174286. http://dx.doi.org/10.1016/j.ejphar.2021.174286.
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Acton, David, and Gareth B. Miles. "Gliotransmission and adenosinergic modulation: insights from mammalian spinal motor networks." Journal of Neurophysiology 118, no. 6 (December 1, 2017): 3311–27. http://dx.doi.org/10.1152/jn.00230.2017.
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Astrocytes are proposed to converse with neurons at tripartite synapses, detecting neurotransmitter release and responding with release of gliotransmitters, which in turn modulate synaptic strength and neuronal excitability. However, a paucity of evidence from behavioral studies calls into question the importance of gliotransmission for the operation of the nervous system in healthy animals. Central pattern generator (CPG) networks in the spinal cord and brain stem coordinate the activation of muscles during stereotyped activities such as locomotion, inspiration, and mastication and may therefore provide tractable models in which to assess the contribution of gliotransmission to behaviorally relevant neural activity. We review evidence for gliotransmission within spinal locomotor networks, including studies indicating that adenosine derived from astrocytes regulates the speed of locomotor activity via metamodulation of dopamine signaling.
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Metzger, Joshua, Helmut Wicht, Horst-Werner Korf, and Martina Pfeffer. "Seasonal Variations of Locomotor Activity Rhythms in Melatonin-Proficient and -Deficient Mice under Seminatural Outdoor Conditions." Journal of Biological Rhythms 35, no. 1 (October 18, 2019): 58–71. http://dx.doi.org/10.1177/0748730419881922.
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Locomotor activity patterns of laboratory mice are widely used to analyze circadian mechanisms, but most investigations have been performed under standardized laboratory conditions. Outdoors, animals are exposed to daily changes in photoperiod and other abiotic cues that might influence their circadian system. To investigate how the locomotor activity patterns under outdoor conditions compare to controlled laboratory conditions, we placed 2 laboratory mouse strains (melatonin-deficient C57Bl and melatonin-proficient C3H) in the garden of the Dr. Senckenbergische Anatomie in Frankfurt am Main. The mice were kept singly in cages equipped with an infrared locomotion detector, a hiding box, nesting material, and with food and water ad libitum. The locomotor activity of each mouse was recorded for 1 year, together with data on ambient temperature, light, and humidity. Chronotype, chronotype stability, total daily activity, duration of the activity period, and daily diurnality indices were determined from the actograms. C3H mice showed clear seasonal differences in the chronotype, its stability, the total daily activity, and the duration of the activity period. These pronounced seasonal differences were not observed in the C57Bl. In both strains, the onset of the main activity period was mainly determined by the evening dusk, whereas the offset was influenced by the ambient temperature. The actograms did not reveal infra-, ultradian, or lunar rhythms or a weekday/weekend pattern. Under outdoor conditions, the 2 strains retained their nocturnal locomotor identity as observed in the laboratory. Our results indicate that the chronotype displays a seasonal plasticity that may depend on the melatoninergic system. Photoperiod and ambient temperature are the most potent abiotic entraining cues. The timing of the evening dusk mainly affects the onset of the activity period; the ambient temperature during this period influences the latter’s duration. Humidity, overall light intensities, and human activities do not affect the locomotor behavior.
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Atsuta, Y., E. Garcia-Rill, and R. D. Skinner. "Characteristics of electrically induced locomotion in rat in vitro brain stem-spinal cord preparation." Journal of Neurophysiology 64, no. 3 (September 1, 1990): 727–35. http://dx.doi.org/10.1152/jn.1990.64.3.727.
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1. Electrical stimulation of two brain stem regions in the decerebrate neonatal rat brain--the mesencephalic locomotor region (MLR) and the medioventral medulla (MED)--were found to elicit rhythmic limb movements in the hind-limb-attached, in vitro, brain stem-spinal cord preparation. 2. Electromyographic (EMG) analysis revealed locomotion similar to that observed during stepping in the adult rat. The step-cycle frequency could be increased by application of higher-amplitude currents; but, unlike the adult, alternation could not be driven to a gallop. 3. Threshold currents for inducing locomotion were significantly lower for stimulation of the MED compared with the MLR. Brain stem transections carried out at midpontine levels demonstrated that the presence of the MLR was not required for the expression of MED-stimulation-induced effects. 4. Substitution of the standard artificial cerebrospinal fluid (aCSF) by magnesium-free aCSF did not affect interlimb relationships and resulted in a significant decrease of the threshold currents for inducing locomotion. 5. Fixation of the limbs during electrical stimulation of brain stem sites altered the amplitude and duration of the EMG patterns, but the basic rhythm and timing of each muscle contraction during the step cycle was not affected. 6. These studies suggest that, although peripheral afferent modulation is evident in the neonatal locomotor control system, descending projections from brain stem-locomotor regions appear capable of modulating the activity of spinal pattern generators as early as the day of birth. However, there may be ceiling to the maximal frequency of stepping possible at this early age, perhaps suggesting a later-developing mechanism for galloping.
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Hinnekens, Elodie, Bastien Berret, Manh-Cuong Do, and Caroline Teulier. "Modularity underlying the performance of unusual locomotor tasks inspired by developmental milestones." Journal of Neurophysiology 123, no. 2 (February 1, 2020): 496–510. http://dx.doi.org/10.1152/jn.00662.2019.
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Motor behaviors are often hypothesized to be set up from the combination of a small number of modules encoded in the central nervous system. These modules are thought to combine such that a variety of motor tasks can be realized, from reproducible tasks such as walking to more unusual locomotor tasks that typically exhibit more step-by-step variability. We investigated the impact of step-by-step variability on the modular architecture of unusual tasks compared with walking. To this aim, 20 adults had to perform walking and two unusual modes of locomotion inspired by developmental milestones (cruising and crawling). Sixteen surface electromyography (EMG) signals were recorded to extract both spatial and temporal modules. Modules were extracted from both averaged and nonaveraged (i.e., single step) EMG signals to assess the significance of step-to-step variability when participants practiced such unusual locomotor tasks. The number of modules extracted from averaged data was similar across tasks, but a higher number of modules was required to reconstruct nonaveraged EMG data of the unusual tasks. Although certain walking modules were shared with cruising and crawling, task-specific modules were necessary to account for the muscle patterns underlying these unusual locomotion modes. These results highlight a more complex modularity (e.g., more modules) for cruising and crawling compared with walking, which was only apparent when the step-to-step variability of EMG patterns was considered. This suggests that considering nonaveraged data is relevant when muscle modularity is studied, especially in motor tasks with high variability as in motor development. NEW & NOTEWORTHY This study addresses the general question of modularity in locomotor control. We demonstrate for the first time the importance of intraindividual variability in the muscle modularity of unusual locomotor behaviors that exhibit greater step-by-step variability than standard walking. Crawling and cruising, the unusual locomotor modes considered, are based on a more complex modular organization than walking. More spatial and temporal modules, task specific or shared with walking modules, are needed to reconstruct muscle patterns.
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Gordon, Keith E., Catherine R. Kinnaird, and Daniel P. Ferris. "Locomotor adaptation to a soleus EMG-controlled antagonistic exoskeleton." Journal of Neurophysiology 109, no. 7 (April 1, 2013): 1804–14. http://dx.doi.org/10.1152/jn.01128.2011.
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Locomotor adaptation in humans is not well understood. To provide insight into the neural reorganization that occurs following a significant disruption to one's learned neuromuscular map relating a given motor command to its resulting muscular action, we tied the mechanical action of a robotic exoskeleton to the electromyography (EMG) profile of the soleus muscle during walking. The powered exoskeleton produced an ankle dorsiflexion torque proportional to soleus muscle recruitment thus limiting the soleus' plantar flexion torque capability. We hypothesized that neurologically intact subjects would alter muscle activation patterns in response to the antagonistic exoskeleton by decreasing soleus recruitment. Subjects practiced walking with the exoskeleton for two 30-min sessions. The initial response to the perturbation was to “fight” the resistive exoskeleton by increasing soleus activation. By the end of training, subjects had significantly reduced soleus recruitment resulting in a gait pattern with almost no ankle push-off. In addition, there was a trend for subjects to reduce gastrocnemius recruitment in proportion to the soleus even though only the soleus EMG was used to control the exoskeleton. The results from this study demonstrate the ability of the nervous system to recalibrate locomotor output in response to substantial changes in the mechanical output of the soleus muscle and associated sensory feedback. This study provides further evidence that the human locomotor system of intact individuals is highly flexible and able to adapt to achieve effective locomotion in response to a broad range of neuromuscular perturbations.
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Tighilet, Brahim, Jacques Leonard, and Michel Lacour. "Betahistine Dihydrochloride Treatment Facilitates Vestibular Compensation in the Cat." Journal of Vestibular Research 5, no. 1 (February 1, 1995): 53–66. http://dx.doi.org/10.3233/ves-1995-5106.
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Unilateral lesion of the vestibular system induces posturo-locomotor deficits that are compensated for with time. Drug therapy is currently used to improve the recovery process and to facilitate vestibular compensation. Betahistine dihydrochloride is an histamine-like substance that has been employed in vestibular pathology; it was found effective in many forms of vertigo and in vestibular-related syndromes. Investigations performed in animal models have shown betahistine-induced neuronal modulations in the vestibular nuclei complex and interactions with the H1 and H3 histamine receptors. Potentially, this substance is therefore capable to interfere with some recovery mechanisms and to improve the behavioral adaptations. But there is at present a total lack of data concerning the influence of betahistine treatment on vestibular compensation in animal models. The aim of this study was to understand the pharmacological activity of betahistine in the restoration of posture and locomotor balance functions in unilateral vestibular neurectomized cats. Posture recovery was assessed by quantifying the surface reaction of the cat’s support as measured while standing erect on its four legs, at rest. Locomotor balance recovery was determined using the rotating beam test, by measuring the maximal performance (max. P.) of the cat and its locomotion speed regulation during the postoperative time period. We have compared the recovery profile and time course of these static (posture) and dynamic (equilibrium) functions in three groups of cats. Two experimental groups were treated at daily doses of 50 mg/kg and 100 mg/kg, respectively. Betahistine dihydrochloride was given orally until complete recovery of posturo-locomotor functions. One untreated control group served as the reference. Results showed that postoperative treatment strongly accelerated the recovery process in both treated groups, inducing a time benefit of around 2 weeks as compared to the controls. Maximum performance of the cats on the rotating beam as well as locomotion speed regulation were highly correlated to the postoperative development of the cat’s support surface, indicating that compensation of the static vestibulospinal deficits conditioned the subsequent locomotor balance recovery. These behavioral data showed that betahistine dihydrochloride constitutes a useful drug therapy for the symptomatic treatment of central vestibular disorders in our animal model of unilateral vestibular lesion. Improvement of vestibular compensation under betahistine postoperative treatment, as evidenced here for the posture and locomotor balance functions, is discussed both in terms of aspecific effect (histamine-induced increase of the level of vigilance) or more direct action in the vestibular nuclei (histamine-induced rebalance of neuronal activity on both sides).
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Preuschoft, H. "On the quality and magnitude of mechanical stresses in the locomotor system during rapid movements." Zeitschrift für Morphologie und Anthropologie 75, no. 3 (June 27, 1985): 245–62. http://dx.doi.org/10.1127/zma/75/1985/245.
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Carrano, Matthew T. "Locomotion in non-avian dinosaurs: integrating data from hindlimb kinematics, in vivo strains, and bone morphology." Paleobiology 24, no. 4 (1998): 450–69. http://dx.doi.org/10.1017/s0094837300020108.
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Analyses of non-avian dinosaur locomotion have been hampered by the lack of an appropriate locomotor analog among extant taxa. Birds, though members of the clade Dinosauria, have undergone significant modifications in hindlimb osteology and musculature. These changes have resulted in a uniquely developed system of limb kinematics (involving a more horizontal femoral posture and knee-dominated limb motion), which precludes the direct use of extant birds as models for non-avian dinosaur locomotion. Analyses of locomotor data from extant birds and mammals suggest a causal link between general hindlimb kinematics, bone strains, and limb bone morphology among these taxa. A model is proposed that relates the amount of torsional loading in femora to bone orientation, such that torsion is maximal in horizontal femora and minimal in vertical femora. Since bone safety factors are lower for torsional shear strains than for longitudinal axial strains, an increase in torsion can potentially affect bone morphology dramatically over evolutionary time. Interpreting the nearly identical limb bone dimensions and limb element proportions of non-avian dinosaurs and mammals in the light of this relationship supports the prediction of similar vertical femoral postures and hip-driven limb kinematics in these two groups.This information can be used to interpret patterns of locomotor evolution within Dinosauria. The evolution of quadrupedalism with large body size and the acquisition of cursorial or graviportal limb morphologies occurred repeatedly but did not affect the underlying uniformity of dinosaur locomotor morphology. Only derived coelurosaurian theropods (paravians) developed significant modifications of the basic dinosaurian patterns of limb use. Changes in theropod hindlimb kinematics and posture apparently began shortly prior to the origin of flight, but did not acquire a characteristically modern avian aspect until after the later acquisition of derived flight characteristics.
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Thompson, Aiko K., Gina Fiorenza, Lindsay Smyth, Briana Favale, Jodi Brangaccio, and Janice Sniffen. "Operant conditioning of the motor-evoked potential and locomotion in people with and without chronic incomplete spinal cord injury." Journal of Neurophysiology 121, no. 3 (March 1, 2019): 853–66. http://dx.doi.org/10.1152/jn.00557.2018.
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Foot drop is very common among people with chronic incomplete spinal cord injury (SCI) and likely stems from SCI that disturbs the corticospinal activation of the ankle dorsiflexor tibialis anterior (TA). Thus, if one can recover or increase the corticospinal excitability reduced by SCI, motor function recovery may be facilitated. Here, we hypothesized that in people suffering from weak dorsiflexion due to chronic incomplete SCI, increasing the TA motor-evoked potential (MEP) through operant up-conditioning can improve dorsiflexion during locomotion, while in people without any injuries, it would have little impact on already normal locomotion. Before and after 24 MEP conditioning or control sessions, locomotor electromyography (EMG) and kinematics were measured. This study reports the results of these locomotor assessments. In participants without SCI, locomotor EMG activity, soleus Hoffmann reflex modulation, and joint kinematics did not change, indicating that MEP up-conditioning or repeated single-pulse transcranial magnetic stimulation (i.e., control protocol) does not influence normal locomotion. In participants with SCI, MEP up-conditioning increased TA activity during the swing-to-swing stance transition phases and ankle joint motion during locomotion in the conditioned leg and increased walking speed consistently. In addition, the swing-phase TA activity and ankle joint motion also improved in the contralateral leg. The results are consistent with our hypothesis. Together with the previous operant conditioning studies in humans and rats, the present study suggests that operant conditioning can be a useful therapeutic tool for enhancing motor function recovery in people with SCI and other central nervous system disorders. NEW & NOTEWORTHY This study examined the functional impact of operant conditioning of motor-evoked potential (MEP) to transcranial magnetic stimulation that aimed to increase corticospinal excitability for the ankle dorsiflexor tibialis anterior (TA). In people with chronic incomplete spinal cord injury (SCI), MEP up-conditioning increased TA activity and improved dorsiflexion during locomotion, while in people without injuries, it had little impact on already normal locomotion. MEP conditioning may potentially be used to enhance motor function recovery after SCI.
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Duda, Sławomir, Damian Gąsiorek, Grzegorz Gembalczyk, Sławomir Kciuk, and Arkadiusz Mężyk. "Mechatronic Device for Locomotor Training." Acta Mechanica et Automatica 10, no. 4 (December 1, 2016): 310–15. http://dx.doi.org/10.1515/ama-2016-0049.
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Abstract This paper presents a novel mechatronic device to support a gait reeducation process. The conceptual works were done by the interdisciplinary design team. This collaboration allowed to perform a device that would connect the current findings in the fields of biomechanics and mechatronics. In the first part of the article shown a construction of the device which is based on the structure of an overhead travelling crane. The rest of the article contains the issues related to machine control system. In the prototype, the control of drive system is conducted by means of two RT-DAC4/PCI real time cards connected with a signal conditioning interface. Authors present the developed control algorithms and optimization process of the controller settings values. The summary contains a comparison of some numerical simulation results and experimental data from the sensors mounted on the device. The measurement data were obtained during the gait of a healthy person.
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Brocard, Frédéric, and Réjean Dubuc. "Differential Contribution of Reticulospinal Cells to the Control of Locomotion Induced By the Mesencephalic Locomotor Region." Journal of Neurophysiology 90, no. 3 (September 2003): 1714–27. http://dx.doi.org/10.1152/jn.00202.2003.
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In lampreys as in other vertebrates, the reticulospinal (RS) system relays inputs from the mesencephalic locomotor region (MLR) to the spinal locomotor networks. Semi-intact preparations of larval sea lamprey were used to determine the relative contribution of the middle (MRRN) and the posterior (PRRN) rhombencephalic reticular nuclei to swimming controlled by the MLR. Intracellular recordings were performed to examine the inputs from the MLR to RS neurons. Stimulation of the MLR elicited monosynaptic excitatory responses of a higher magnitude in the MRRN than in the PRRN. This differential effect was not attributed to intrinsic properties of RS neurons. Paired recordings showed that at threshold intensity for swimming, spiking activity was primarily elicited in RS cells of the MRRN. Interestingly, cells of the PRRN began to discharge at higher stimulation intensities only when MRRN cells had reached their maximal discharge rate. Glutamate antagonists were ejected in either nucleus to reduce their activity. Ejections over the MRRN increased the stimulation threshold for evoking locomotion and resulted in a marked decrease in the swimming frequency and the strength of the muscle contractions. Ejections over the PRRN decreased the frequency of swimming. This study provides support for the concept that RS cells show a specific recruitment pattern during MLR-induced locomotion. RS cells in the MRRN are primarily involved in initiation and maintenance of low-intensity swimming. At higher frequency locomotor rhythm, RS cells in both the MRRN and the PRRN are recruited.
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Foweather, Lawrence, Matteo Crotti, Jonathan D. Foulkes, Mareesa V. O’Dwyer, Till Utesch, Zoe R. Knowles, Stuart J. Fairclough, Nicola D. Ridgers, and Gareth Stratton. "Foundational Movement Skills and Play Behaviors during Recess among Preschool Children: A Compositional Analysis." Children 8, no. 7 (June 24, 2021): 543. http://dx.doi.org/10.3390/children8070543.
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This study aimed to examine the associations between play behaviors during preschool recess and foundational movement skills (FMS) in typically developing preschool children. One hundred and thirty-three children (55% male; mean age 4.7 ± 0.5 years) from twelve preschools were video-assessed for six locomotor and six object-control FMS using the Champs Motor Skill Protocol. A modified System for Observing Children’s Activity and Relationships during Play assessed play behaviors during preschool recess. Associations between the composition of recess play behaviors with FMS were analyzed using compositional data analysis and linear regression. Results: Relative to time spent in other types of play behaviors, time spent in play without equipment was positively associated with total and locomotor skills, while time spent in locomotion activities was negatively associated with total and locomotor skills. No associations were found between activity level and group size play behavior compositions and FMS. The findings suggest that activity type play behaviors during recess are associated with FMS. While active games without equipment appear beneficial, preschool children may need a richer playground environment, including varied fixed and portable equipment, to augment the play-based development of FMS.
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Barstow, Amy, and Renate Weller. "The horse – the athlete with the ultimate locomotor system." Physiology News, Spring 2016 (April 1, 2016): 26–30. http://dx.doi.org/10.36866/pn.102.26.
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Shchubelka, Kh M., O. T. Oleksyk, and T. M. Hanych. "Condition of locomotor system in patients with diabetes mellitus." INTERNATIONAL JOURNAL OF ENDOCRINOLOGY 13, no. 6 (October 30, 2017): 450–54. http://dx.doi.org/10.22141/2224-0721.13.6.2017.112891.
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