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Baratta, Alexander M. "Revealing stance through passive voice." Journal of Pragmatics 41, no. 7 (2009): 1406–21. http://dx.doi.org/10.1016/j.pragma.2008.09.010.
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Yang, Jiliu. "Passive Voice and Stance Taking in Korean Academic Discourse." Korean Society of Bilingualism 91 (March 31, 2023): 69–100. https://doi.org/10.17296/korbil.2023..91.69.
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This paper discusses passive voice usage and how authors reflect their stance through passive voice in Korean academic papers. While traditionally considered one of the distinctive features in academic writing, passive voice can reveal the author's stance by deleting or de-emphasizing the subject within a sentence. Based on an analysis of 21 published research articles from Korean language and electronic engineering disciplines, the results indicate differences in the frequency of using passive voice across disciplines. The findings also suggest that authors use passive sentences for different purposes depending on the agent. When the agents are the authors themselves, they use passive voice in four contexts: making claims, establishing a procedure, interpreting data and research results, and making predictions and suggestions. On the other hand, the authors prefer the passive voice in two contexts when the agents are the others: pointing out the shortcomings of previous studies and presenting a critical perspective on research subjects. Although the corpus of this research is small and limited to two specific majors, the results may help students understand or make a good choice to use passive voice. Furthermore, the results will help students on handling stance taking in academic papers.
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Henry, Sharon M., Joyce Fung, and Fay B. Horak. "Effect of Stance Width on Multidirectional Postural Responses." Journal of Neurophysiology 85, no. 2 (2001): 559–70. http://dx.doi.org/10.1152/jn.2001.85.2.559.
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The effect of stance width on postural responses to 12 different directions of surface translations was examined. Postural responses were characterized by recording 11 lower limb and trunk muscles, body kinematics, and forces exerted under each foot of 7 healthy subjects while they were subjected to horizontal surface translations in 12 different, randomly presented directions. A quasi-static approach of force analysis was done, examining force integrals in three different epochs (background, passive, and active periods). The latency and amplitude of muscle responses were quantified for each direction, and muscle tuning curves were used to determine the spatial activation patterns for each muscle. The results demonstrate that the horizontal force constraint exerted at the ground was lessened in the wide, compared with narrow, stance for humans, a similar finding to that reported by Macpherson for cats. Despite more trunk displacement in narrow stance, there were no significant changes in body center of mass (CoM) displacement due to large changes in center of pressure (CoP), especially in response to lateral translations. Electromyographic (EMG) magnitude decreased for all directions in wide stance, particularly for the more proximal muscles, whereas latencies remained the same from narrow to wide stance. Equilibrium control in narrow stance was more of an active postural strategy that included regulating the loading/unloading of the limbs and the direction of horizontal force vectors. In wide stance, equilibrium control relied more on an increase in passive stiffness resulting from changes in limb geometry. The selective latency modulation of the proximal muscles with translation direction suggests that the trunk was being actively controlled in all directions. The similar EMG latencies for both narrow and wide stance, with modulation of only the muscle activation magnitude as stance width changed, suggest that the same postural synergy was only slightly modified for a change in stance width. Nevertheless, the magnitude of the trunk displacement, as well as of CoP displacement, was modified based on the degree of passive stiffness in the musculoskeletal system, which increased with stance width. The change from a more passive to an active horizontal force constraint, to larger EMG magnitudes especially in the trunk muscles and larger trunk and CoP excursions in narrow stance are consistent with a more effortful response for equilibrium control in narrow stance to perturbations in all directions.
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Bauer, Jeremy, K. Patrick Do, Jing Feng, and Michael Aiona. "Calf lengthening may improve knee recurvatum in specific children with spastic diplegic cerebral palsy." Journal of Children's Orthopaedics 14, no. 4 (2020): 353–57. http://dx.doi.org/10.1302/1863-2548.14.200092.
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Purpose Knee hyperextension in stance is a difficult condition to treat in children with spastic diplegic cerebral palsy (CP). In children with passive knee hyperextension, the presence of contracture or spasticity of the calf leads to knee hyperextension in stance phase. We hypothesize surgical treatment of the contracture of the calf will lead to less knee hyperextension. Methods We performed a retrospective review of children who were evaluated in our movement laboratory over 23 years with a diagnosis of CP Gross Motor Function Classification System I, II or III. We selected children who had passive knee hyperextension on exam and who underwent calf lengthening surgery. Children were divided into two groups: early recurvatum (ER) (n = 20) and late recurvatum (LR) (n = 14). Results There was no difference in the preoperative passive knee extension among the groups or the surgeries performed. For children who had passive knee hyperextension, calf lengthening improved static dorsiflexion with knee flexion on clinical exam by 9.3° in the ER group, 9.6° in the LR group as well as dorsiflexion with knee extension on clinical exam by 9.5° in the ER group and 6.4° in the LR group. The kinematic data showed that the ER group improved their knee hyperextension by 11° (p < 0.001), whereas the LR group did not significantly change their stance phase knee position. Conclusion Children with passive knee hyperextension who have a calf contracture and walk in knee hyperextension in the first half of stance phase may improve after calf lengthening. Level of Evidence: III
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Youberg, Linda Dowdy, Mark W. Cornwall, Thomas G. McPoil, and Patrick R. Hannon. "The Amount of Rearfoot Motion Used During the Stance Phase of Walking." Journal of the American Podiatric Medical Association 95, no. 4 (2005): 376–82. http://dx.doi.org/10.7547/0950376.
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The purpose of this study was to determine the proportion of available passive frontal plane rearfoot motion that is used during the stance phase of walking. Data were collected from 40 healthy, asymptomatic volunteer subjects (20 men and 20 women) aged 23 to 44 years. Passive inversion and eversion motion was measured in a nonweightbearing position by manually moving the calcaneus. Dynamic rearfoot motion was referenced to a vertical calcaneus and tibia and was measured using a three-dimensional electromagnetic motion-analysis system. The results indicated that individuals used 68.1% of their available passive eversion range of motion and 13.2% of their available passive inversion range of motion during walking. The clinical implication of individuals’ regularly operating at or near the end point of their available rearfoot eversion range of motion is discussed. (J Am Podiatr Med Assoc 95(4): 376–382, 2005)
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Holm, Jonathan K., Jonas Contakos, Sang-Wook Lee, and John Jang. "Energetics and Passive Dynamics of the Ankle in Downhill Walking." Journal of Applied Biomechanics 26, no. 4 (2010): 379–89. http://dx.doi.org/10.1123/jab.26.4.379.
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This study investigated the energetics of the human ankle during the stance phase of downhill walking with the goal of modeling ankle behavior with a passive spring and damper mechanism. Kinematic and kinetic data were collected on eight male participants while walking down a ramp with inclination varying from 0° to 8°. The ankle joint moment in the sagittal plane was calculated using inverse dynamics. Mechanical energy injected or dissipated at the ankle joint was computed by integrating the power across the duration of the stance phase. The net mechanical energy of the ankle was approximately zero for level walking and monotonically decreased (i.e., became increasingly negative) during downhill walking as the slope decreased. The indication is that the behavior of the ankle is energetically passive during downhill walking, playing a key role in dissipating energy from one step to the next. A passive mechanical model consisting of a pin joint coupled with a revolute spring and damper was fit to the ankle torque and its parameters were estimated for each downhill slope using linear regression. The passive model demonstrated good agreement with actual ankle dynamics as indicated by low root-mean-square error values. These results indicate the stance phase behavior of the human ankle during downhill walking may be effectively duplicated by a passive mechanism with appropriately selected spring and damping characteristics.
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Hu, Yong, Gangfeng Yan, and Zhiyun Lin. "Stable running of a planar underactuated biped robot." Robotica 29, no. 5 (2010): 657–65. http://dx.doi.org/10.1017/s0263574710000512.
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SUMMARYThis paper investigates the stable-running problem of a planar underactuated biped robot, which has two springy telescopic legs and one actuated joint in the hip. After modeling the robot as a hybrid system with multiple continuous state spaces, a natural passive limit cycle, which preserves the system energy at touchdown, is found using the method of Poincaré shooting. It is then checked that the passive limit cycle is not stable. To stabilize the passive limit cycle, an event-based feedback control law is proposed, and also to enlarge the basin of attraction, an additive passivity-based control term is introduced only in the stance phase. The validity of our control strategies is illustrated by a series of numerical simulations.
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Goodworth, Adam D., Patricia Mellodge, and Robert J. Peterka. "Stance width changes how sensory feedback is used for multisegmental balance control." Journal of Neurophysiology 112, no. 3 (2014): 525–42. http://dx.doi.org/10.1152/jn.00490.2013.
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A multilink sensorimotor integration model of frontal plane balance control was developed to determine how stance width influences the use of sensory feedback in healthy adults. Data used to estimate model parameters came from seven human participants who stood on a continuously rotating surface with three different stimulus amplitudes, with eyes open and closed, and at four different stance widths. Dependent variables included lower body (LB) and upper body (UB) sway quantified by frequency-response functions. Results showed that stance width had a major influence on how parameters varied across stimulus amplitude and between visual conditions. Active mechanisms dominated LB control. At narrower stances, with increasing stimulus amplitude, subjects used sensory reweighting to shift reliance from proprioceptive cues to vestibular and/or visual cues that oriented the LB more toward upright. When vision was available, subjects reduced reliance on proprioception and increased reliance on vision. At wider stances, LB control did not exhibit sensory reweighting. In the UB system, both active and passive mechanisms contributed and were dependent on stance width. UB control changed across stimulus amplitude most in wide stance (opposite of the pattern found in LB control). The strong influence of stance width on sensory integration and neural feedback control implies that rehabilitative therapies for balance disorders can target different aspects of balance control by using different stance widths. Rehabilitative strategies designed to assess or modify sensory reweighting will be most effective with the use of narrower stances, whereas wider stances present greater challenges to UB control.
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Arch, Elisa S., Steven J. Stanhope, and Jill S. Higginson. "Passive-dynamic ankle–foot orthosis replicates soleus but not gastrocnemius muscle function during stance in gait: Insights for orthosis prescription." Prosthetics and Orthotics International 40, no. 5 (2016): 606–16. http://dx.doi.org/10.1177/0309364615592693.
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Background: Passive-dynamic ankle–foot orthosis characteristics, including bending stiffness, should be customized for individuals. However, while conventions for customizing passive-dynamic ankle–foot orthosis characteristics are often described and implemented in clinical practice, there is little evidence to explain their biomechanical rationale. Objectives: To develop and combine a model of a customized passive-dynamic ankle–foot orthosis with a healthy musculoskeletal model and use simulation tools to explore the influence of passive-dynamic ankle–foot orthosis bending stiffness on plantar flexor function during gait. Study design: Dual case study. Methods: The customized passive-dynamic ankle–foot orthosis characteristics were integrated into a healthy musculoskeletal model available in OpenSim. Quasi-static forward dynamic simulations tracked experimental gait data under several passive-dynamic ankle–foot orthosis conditions. Predicted muscle activations were calculated through a computed muscle control optimization scheme. Results: Simulations predicted that the passive-dynamic ankle–foot orthoses substituted for soleus but not gastrocnemius function. Induced acceleration analyses revealed the passive-dynamic ankle–foot orthosis acts like a uniarticular plantar flexor by inducing knee extension accelerations, which are counterproductive to natural knee kinematics in early midstance. Conclusion: These passive-dynamic ankle–foot orthoses can provide plantar flexion moments during mid and late stance to supplement insufficient plantar flexor strength. However, the passive-dynamic ankle–foot orthoses negatively influenced knee kinematics in early midstance. Clinical relevance Identifying the role of passive-dynamic ankle–foot orthosis stiffness during gait provides biomechanical rationale for how to customize passive-dynamic ankle–foot orthoses for patients. Furthermore, these findings can be used in the future as the basis for developing objective prescription models to help drive the customization of passive-dynamic ankle–foot orthosis characteristics.
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Oda, Hitoshi, Shiho Fukuda, Ryo Tsujinaka, Han Gao, and Koichi Hiraoka. "Short-Term Reproduction of Active Movement with Visual Feedback and Passive Movement with a Therapist’s Hands." Brain Sciences 14, no. 6 (2024): 531. http://dx.doi.org/10.3390/brainsci14060531.
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Reproducing instructed movements is crucial for practice in motor learning. In this study, we compared the short-term reproduction of active pelvis movements with visual feedback and passive movement with the therapist’s hands in an upright stance. Sixteen healthy males (M age = 34.1; SD = 10.2 years) participated in this study. In one condition, healthy males maintained an upright stance while a physical therapist moved the participant’s pelvis (passive movement instruction), and in a second condition, the participant actively moved their pelvis with visual feedback of the target and the online trajectory of the center of pressure (active movement instruction). Reproduction errors (displacement of the center of pressure in the medial–lateral axis) 10 s after the passive movement instruction were significantly greater than after the active movement instruction (p < 0.001), but this difference disappeared 30 s after the instruction (p = 0.118). Error of movement reproduction in the anterior–posterior axis after the passive movement instruction was significantly greater than after the active movement instruction, no matter how long the retention interval was between the instruction and reproduction phases (p = 0.025). Taken together, active pelvis movements with visual feedback, rather than passive movement with the therapist’s hand, is better to be used for instructing pelvis movements.
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Uchytil, Jaroslav, Daniel Jandacka, David Zahradnik, Roman Farana, and Miroslav Janura. "Temporal–spatial parameters of gait in transfemoral amputees: Comparison of bionic and mechanically passive knee joints." Prosthetics and Orthotics International 38, no. 3 (2013): 199–203. http://dx.doi.org/10.1177/0309364613492789.
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Background:A symmetrical gait affords the most efficient walking pattern. Bionic prostheses should provide better gait symmetry than mechanically passive prostheses with respect to a nonpathological gait.Objectives:To compare the basic temporal–spatial parameters of gait in transfemoral amputees fitted with bionic or mechanically passive prosthetic knees with those of subjects with a nonpathological gait.Study design:Three-dimensional gait analysis using an optoelectronic device.Methods:Eight transfemoral amputees participated in the study. Subjects walked across two dynamometric platforms a total of 15 times. Movement kinematics were measured using optoelectronic stereophotogrammetry.Results:The swing time of the affected limb in patients fitted with a mechanically passive knee joint was longer than that of the nonaffected limb by 0.055 s (effect size = 1.57). Compared with the control group, the swing time of the prosthetic limb in patients fitted with a mechanically passive knee was longer by 0.042 s (effect size = 2.1). Similarly, the stance time of the nonaffected limb was longer by 0.047 s (effect size = 1.07).Conclusions:Compared with a mechanically passive knee joint, a bionic knee joint evinced gait symmetry. Both the stance time and the swing time for amputees with a bionic knee were similar to those of nonamputees.Clinical relevanceProsthetists aim to design prostheses that achieve a good symmetry between the healthy and affected limbs. The use of bionic technology achieves a level of symmetry approaching that observed in nonamputees.
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Zaier, Riadh, and A. Al-Yahmedi. "Design of Biomechanical Legs with a Passive Toe Joint for Enhanced Human-like Walking." Journal of Engineering Research [TJER] 14, no. 2 (2017): 166. http://dx.doi.org/10.24200/tjer.vol14iss2pp166-181.
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This paper presents the design procedure of a biomechanical leg, with a passive toe joint, which is capable of mimicking the human walking. This leg has to provide the major features of human gait in the motion trajectories of the hip, knee, ankle, and toe joints. Focus was given to the approach of designing the passive toe joint of the biomechanical leg in its role and effectiveness in performing human like motion. This study was inspired by experimental and theoretical studies in the fields of biomechanics and robotics. Very light materials were mainly used in the design process. Aluminum and carbon fiber parts were selected to design the proposed structure of this biomechanical leg, which is to be manufactured in the Mechanical Lab of the Sultan Qaboos University (SQU). The capabilities of the designed leg to perform the normal human walking are presented. This study provides a noteworthy and unique design for the passive toe joint, represented by a mass-spring damper system, using torsion springs in the foot segment. The working principle and characteristics of the passive toe joint are discussed. Four-designed cases, with different design parameters, for the passives toe joint system are presented to address the significant role that the passive toe joint plays in human-like motion. The dynamic motion that is used to conduct this comparison was the first stage of the stance motion. The advantages of the presence of the passive toe joint in gait, and its effect on reducing the energy consumption by the other actuated joints are presented and a comparison between the four-designed cases is discussed.
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Abu-Akel, Ahmad M., Ian A. Apperly, Stephen J. Wood, and Peter C. Hansen. "Re-imaging the intentional stance." Proceedings of the Royal Society B: Biological Sciences 287, no. 1925 (2020): 20200244. http://dx.doi.org/10.1098/rspb.2020.0244.
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The commonly used paradigm to investigate Dennet's ‘intentional stance’ compares neural activation when participants compete with a human versus a computer. This paradigm confounds whether the opponent is natural or artificial and whether it is intentional or an automaton. This functional magnetic resonance imaging study is, to our knowledge, the first to investigate the intentional stance by orthogonally varying perceptions of the opponents' intentionality (responding actively or passively according to a script) and embodiment (human or a computer). The mere perception of the opponent (whether human or computer) as intentional activated the mentalizing network: the temporoparietal junction (TPJ) bilaterally, right temporal pole, anterior paracingulate cortex (aPCC) and the precuneus. Interacting with humans versus computers induced activations in a more circumscribed right lateralized subnetwork within the mentalizing network, consisting of the TPJ and the aPCC, possibly reflective of the tendency to spontaneously attribute intentionality to humans. The interaction between intentionality (active versus passive) and opponent (human versus computer) recruited the left frontal pole, possibly in response to violations of the default intentional stance towards humans and computers. Employing an orthogonal design is important to adequately capture Dennett's conception of the intentional stance as a mentalizing strategy that can apply equally well to humans and other intentional agents.
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Clark, Kenneth P., and Peter G. Weyand. "Are running speeds maximized with simple-spring stance mechanics?" Journal of Applied Physiology 117, no. 6 (2014): 604–15. http://dx.doi.org/10.1152/japplphysiol.00174.2014.
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Are the fastest running speeds achieved using the simple-spring stance mechanics predicted by the classic spring-mass model? We hypothesized that a passive, linear-spring model would not account for the running mechanics that maximize ground force application and speed. We tested this hypothesis by comparing patterns of ground force application across athletic specialization (competitive sprinters vs. athlete nonsprinters, n = 7 each) and running speed (top speeds vs. slower ones). Vertical ground reaction forces at 5.0 and 7.0 m/s, and individual top speeds ( n = 797 total footfalls) were acquired while subjects ran on a custom, high-speed force treadmill. The goodness of fit between measured vertical force vs. time waveform patterns and the patterns predicted by the spring-mass model were assessed using the R2 statistic (where an R2 of 1.00 = perfect fit). As hypothesized, the force application patterns of the competitive sprinters deviated significantly more from the simple-spring pattern than those of the athlete, nonsprinters across the three test speeds ( R2 <0.85 vs. R2 ≥ 0.91, respectively), and deviated most at top speed ( R2 = 0.78 ± 0.02). Sprinters attained faster top speeds than nonsprinters (10.4 ± 0.3 vs. 8.7 ± 0.3 m/s) by applying greater vertical forces during the first half (2.65 ± 0.05 vs. 2.21 ± 0.05 body wt), but not the second half (1.71 ± 0.04 vs. 1.73 ± 0.04 body wt) of the stance phase. We conclude that a passive, simple-spring model has limited application to sprint running performance because the swiftest runners use an asymmetrical pattern of force application to maximize ground reaction forces and attain faster speeds.
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Asano, Fumihiko, and Yuji Harata. "Sliding Passive Dynamic Walking of Compass-Like Biped Robot: Collision Modeling, Necessary Conditions, and Complexity." Journal of Robotics and Mechatronics 29, no. 3 (2017): 509–19. http://dx.doi.org/10.20965/jrm.2017.p0509.
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[abstFig src='/00290003/06.jpg' width='300' text='Short- and long-period sliding passive compass gaits' ] This paper investigates the modeling and analysis of the sliding passive dynamic walking of a compass-like biped robot with pointed feet. First, we present the passive compass-like biped model and redevelop the inelastic collision equation for stance-leg exchange, taking the impulsive frictional effect into account. Second, we numerically show that two different steady motions, the short- and long-period sliding passive compass gaits, can be generated according to the initial conditions in the presence of the effects of the hip damper and impulsive frictional force. Furthermore, we numerically analyze the change characteristics of the gait descriptors with respect to the system parameters, and we discuss the relationship between the short- and long-period gaits.
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Suzuki, Soichiro, Ying Cao, Masamichi Takada, and Kentaro Oi. "Climbing and Turning Control of a Biped Passive Walker by Periodic Input Based on Frequency Entrainment." Advanced Engineering Forum 2-3 (December 2011): 48–52. http://dx.doi.org/10.4028/www.scientific.net/aef.2-3.48.
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This study is aimed at stabilizing a three dimensional biped passive walker in various environments and achieving climbing and turning control. The novel control method synchronizes a period of the changing motion of the stance leg in frontal plane (frontal motion) with a period of the swing leg by periodic input in order to stabilize the three dimensional passive walker. A mechanical oscillator is utilized to change the period of the frontal motion. The target path of the oscillator is automatically generated based on frequency entrainment in order to adjust the period of the frontal motion. In the climbing and turning control of the passive walker, the amplitude and the phase generating algorithm of the target path of the oscillator are improved. It is analytically demonstrated that the biped passive walker can be stabilized even in climbing and turning.
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Mummolo, Carlotta, and Joo H. Kim. "Passive and dynamic gait measures for biped mechanism: formulation and simulation analysis." Robotica 31, no. 4 (2012): 555–72. http://dx.doi.org/10.1017/s0263574712000586.
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SUMMARYUnderstanding and mimicking human gait is essential for design and control of biped walking robots. The unique characteristics of normal human gait are described as passive dynamic walking, whereas general human gait is neither completely passive nor always dynamic. To study various walking motions, it is important to quantify the different levels of passivity and dynamicity, which have not been addressed in the current literature. In this paper, we introduce the initial formulations of Passive Gait Measure (PGM) and Dynamic Gait Measure (DGM) that quantify passivity and dynamicity, respectively, of a given biped walking motion, and the proposed formulations will be demonstrated for proof-of-concepts using gait simulation and analysis. The PGM is associated with the optimality of natural human walking, where the passivity weight functions are proposed and incorporated in the minimization of physiologically inspired weighted actuator torques. The PGM then measures the relative contribution of the stance ankle actuation. The DGM is associated with the gait stability, and quantifies the effects of inertia in terms of the Zero-Moment Point and the ground projection of center of mass. In addition, the DGM takes into account the stance foot dimension and the relative threshold between static and dynamic walking. As examples, both human-like and robotic walking motions during single support phase are generated for a planar biped system using the passivity weights and proper gait parameters. The calculated PGM values show more passive nature of human-like walking as compared with the robotic walking. The DGM results verify the dynamic nature of normal human walking with anthropomorphic foot dimension. In general, the DGMs for human-like walking are greater than those for robotic walking. The resulting DGMs also demonstrate their dependence on the stance foot dimension as well as the walking motion; for a given walking motion, smaller foot dimension results in increased dynamicity. Future work on experimental validation and demonstration will involve actual walking robots and human subjects. The proposed results will benefit the human gait studies and the development of walking robots.
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Russell, S., K. P. Granata, and P. Sheth. "Virtual Slope Control of a Forward Dynamic Bipedal Walker." Journal of Biomechanical Engineering 127, no. 1 (2005): 114–22. http://dx.doi.org/10.1115/1.1835358.
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Active joint torques are the primary source of power and control in dynamic walking motion. However the amplitude, rate, timing and phasic behavior of the joint torques necessary to achieve a natural and stable performance are difficult to establish. The goal of this study was to demonstrate the feasibility and stable behavior of an actively controlled bipedal walking simulation wherein the natural system dynamics were preserved by an active, nonlinear, state-feedback controller patterned after passive downhill walking. A two degree-of-freedom, forward-dynamic simulation was implemented with active joint torques applied at the hip joints and stance leg ankle. Kinematic trajectories produced by the active walker were similar to passive dynamic walking with active joint torques influenced by prescribed walking velocity. The control resulted in stable steady-state gait patterns, i.e. eigenvalue magnitudes of the stride function were less than one. The controller coefficient analogous to the virtual slope was modified to successfully control average walking velocity. Furture developments are necessary to expand the range of walking velocities.
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Akimoto, Toshinari, Nobuyuki Terada, and Akihiro Matsumoto. "Dynamic Walking Analysis of the Ankle-Driven Quasi-Passive Walking Machines." Journal of Robotics and Mechatronics 20, no. 2 (2008): 200–205. http://dx.doi.org/10.20965/jrm.2008.p0200.
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We designed and developed an ankle-driven quasi-passive dynamic walking machine and modeled it focusing on the double-stance phase for accurate analyzing realistic movement. We used a penalty function to formulate a motion equation and changed the walking speed of an ankle-driven walking machine by changing kick and brake torque. Computer simulation confirmed the feasibility of brake torque from the energy point of view and walking stability.
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Pau, Massimiliano, Gianfranco Ibba, and Giuseppe Attene. "Fatigue-Induced Balance Impairment in Young Soccer Players." Journal of Athletic Training 49, no. 4 (2014): 454–61. http://dx.doi.org/10.4085/1062-6050-49.2.12.
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Context: Although balance is generally recognized to be an important feature in ensuring good performance in soccer, its link with functional performance remains mostly unexplored, especially in young athletes. Objective: To investigate changes in balance induced by fatigue for unipedal and bipedal static stances in young soccer players. Design: Crossover study. Setting: Biomechanics laboratory and outdoor soccer field. Patients or Other Participants: Twenty-one male soccer players (age = 14.5 ± 0.2 years, height = 164.5 ± 5.6 cm, mass = 56.8 ± 6.8 kg). Intervention(s): Static balance was assessed with postural-sway analysis in unipedal and bipedal upright stance before and after a fatigue protocol consisting of a repeated sprint ability (RSA) test (2 × 15-m shuttle sprint interspersed with 20 seconds of passive recovery, repeated 6 times). Main Outcome Measure(s): On the basis of the center-of-pressure (COP) time series acquired during the experimental tests, we measured sway area, COP path length, and COP maximum displacement and velocity in the anteroposterior and mediolateral directions. Results: Fatigue increased all sway values in bipedal stance and all values except COP velocity in the mediolateral direction in unipedal stance. Fatigue index (calculated on the basis of RSA performance) was positively correlated with fatigue/rest sway ratio for COP path length and COP velocity in the anteroposterior and mediolateral directions for nondominant single-legged stance. Conclusions: Fatigued players exhibited reduced performance of the postural-control system. Participants with better performance in the RSA test appeared less affected by balance impairment, especially in single-legged stance.
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Pratt, C. A., J. Fung, and J. M. Macpherson. "Stance control in the chronic spinal cat." Journal of Neurophysiology 71, no. 5 (1994): 1981–85. http://dx.doi.org/10.1152/jn.1994.71.5.1981.
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1. A longitudinal study of the control of quiet and perturbed stance was conducted before and for 1 yr after complete spinal transection (T12) in a cat trained to stand on a moveable force platform. 2. With daily training, the spinal cat recovered full weight support and some intermittent control of lateral stability within 1 mo. Within the second month postspinalization, the spinal cat achieved the ability to maintain independent, unassisted stance (no external support or stimulation) for up to 45 s during quiet stance, as well as for 62–97% of the trials of horizontal translations of the support surface. 3. Control of lateral stability in the spinal cat was severely compromised, however, as eventually the spinal cat always lost its balance. Head movements and the tendency for the hindlimbs to initiate stepping movements were more destabilizing than platform translations. 4. Our preliminary results indicate that the recovery of partial lateral stability of the hindquarters in the spinal cat is the product of passive muscle properties and segmental reflexes, which, in isolation can provide only limited balance control in the chronic spinal cat.
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Adiputra, Dimas, Mohd Azizi Abdul Rahman, Ubaidillah, et al. "Control Reference Parameter for Stance Assistance Using a Passive Controlled Ankle Foot Orthosis—A Preliminary Study." Applied Sciences 9, no. 20 (2019): 4416. http://dx.doi.org/10.3390/app9204416.
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This paper aims to present a preliminary study of control reference parameters for stance assistance among different subjects and walking speeds using a passive-controlled ankle foot orthosis. Four young male able-bodied subjects with varying body mass indexes (23.842 ± 4.827) walked in three walking speeds of 1, 3, and 5 km/h. Two control references, average ankle torque (aMa), and ankle angular velocity (aω), which can be implemented using a magnetorheological brake, were measured. Regression analysis was conducted to identify suitable control references in the three different phases of the stance. The results showed that aω has greater correlation (p) with body mass index and walking speed compared to aMa in the whole stance phase (p1(aω) = 0.666 > p1(aMa) = 0.560, p2(aω) = 0.837 > p2(aMa) = 0.277, and p3(aω) = 0.839 > p3(aMa) = 0.369). The estimation standard error (Se) of the aMa was found to be generally higher than of aω (Se1(aMa) = 2.251 > Se1(aω) = 0.786, Se2(aMa) = 1.236 > Se2(aω) = 0.231, Se3(aMa) = 0.696 < Se3(aω) = 0.755). Future studies should perform aω estimation based on body mass index and walking speed, as suggested by the higher correlation and lower standard error as compared to aMa. The number of subjects and walking speed scenarios should also be increased to reduce the standard error of control reference parameters estimation.
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Muraoka, Tetsuro, Tadashi Muramatsu, Daisuke Takeshita, Hiroaki Kanehisa, and Tetsuo Fukunaga. "Estimation of Passive Ankle Joint Moment during Standing and Walking." Journal of Applied Biomechanics 21, no. 1 (2005): 72–84. http://dx.doi.org/10.1123/jab.21.1.72.
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This study estimated the passive ankle joint moment during standing and walking initiation and its contribution to total ankle joint moment during that time. The decrement of passive joint moment due to muscle fascicle shortening upon contraction was taken into account. Muscle fascicle length in the medial gastrocnemius, which was assumed to represent muscle fascicle length in plantarflexors, was measured using ultrasonography during standing, walking initiation, and cyclical slow passive ankle joint motion. Total ankle joint moment during standing and walking initiation was calculated from ground reaction forces and joint kinematics. Passive ankle joint moment during the cyclical ankle joint motion was measured via a dynamometer. Passive ankle joint moment during standing and at the time (Tp) when the MG muscle-tendon complex length was longest in the stance phase during walking initiation were 2.3 and 5.4 Nm, respectively. The muscle fascicle shortened by 2.9 mm during standing compared with the length at rest, which decreased the contribution of passive joint moment from 19.9% to 17.4%. The muscle fascicle shortened by 4.3 mm at Tp compared with the length at rest, which decreased the contribution of passive joint moment from 8.0% to 5.8%. These findings suggest that (a) passive ankle joint moment plays an important role during standing and walking initiation even in view of the decrement of passive joint moment due to muscle fascicle shortening upon muscle contraction, and (b) muscle fascicle shortening upon muscle contraction must be taken into account when estimating passive joint moment during movements.
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Manikowska, Faustyna, Sabina Brazevič, Marek Jóźwiak, and Maria K. Lebiedowska. "Contribution of Different Impairments to Restricted Knee Flexion during Gait in Individuals with Cerebral Palsy." Journal of Personalized Medicine 12, no. 10 (2022): 1568. http://dx.doi.org/10.3390/jpm12101568.
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The coexistence of overlapping impairments modulates the knee pattern in the swing phase of walking in children with cerebral palsy (CP). The impact and contribution of each impairment to the reduction of knee range-of-motion is unknown. The aim of the study was to establish the gradation of the impact of individual coexisting impairments on the knee flexion range-of-motion. Passive range-of-motion, selective motor control, strength, and spasticity from 132 patients (Male = 76, Female = 56, age:11 ± 4 years) with spastic CP were tested with clinical tools. Knee flexion range-of-motion at terminal stance, pre-swing, and initial swing phases were assessed by gait analysis. Hypertonia (β = −5.75) and weakness (β = 2.76) of knee extensors were associated with lower range of knee flexion (R2 = 0.0801, F = 11.0963, p < 0.0001). The predictive factors (R2 = 0.0744, F = 7.2135, p < 0.0001) were strength (β = 4.04) and spasticity (β = −2.74) of knee extensors and strength of hip flexors (β = −2.01); in swing those were knee extensors hypertonia (β = −2.55) and passive range of flexion (β = 0.16) (R2 = 0.0398, F = 3.4010, p = 0.01). Hypertonia of knee extensors has the strongest impact on knee flexion range-of-motion; secondary is the strength of knee extensors. The knee extensors strength with knee extensors hypertonia and strength of hip flexors contributes in stance. Knee extensors hypertonia with passive knee flexion range-of-motion contributes in swing.
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Murabayashi, Mai, Takuya Mitani, and Koh Inoue. "Development and Evaluation of a Passive Mechanism for a Transfemoral Prosthetic Knee That Prevents Falls during Running Stance." Prosthesis 4, no. 2 (2022): 172–83. http://dx.doi.org/10.3390/prosthesis4020018.
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Existing prosthetic knees used by transfemoral amputees have function almost akin to non-friction hinge joints during the running stance phase. Therefore, transfemoral amputees who wish to run need sufficient strength in their hip extension muscles and appropriate prosthetic leg swing motion to avoid falling due to unintended prosthetic knee flexion. This requires much training and practice. The present study aimed to develop a passive mechanism for a transfemoral prosthetic knee to prevent unintended prosthetic knee flexion during the running stance phase. The proposed mechanism restricts only flexion during the prosthetic stance phase with a load on the prosthetic knee regardless of the joint angle of the prosthetic knee. The load on the prosthetic knee required to maintain locked flexion was analyzed. We developed a rough prototype and conducted an evaluation experiment with an intact participant attached to a simulated prosthetic limb and the prototype. The results of level walking showed that the proposed mechanism limits knee flexion, as designed. The results of the preliminary trial suggest that the proposed mechanism functions appropriately during running, where the load on the prosthetic knee is larger than that during walking.
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Abelew, Thomas A., Brian J. Cuda, Jonathan E. Koontz, Julia C. Stell, and Marie A. Johanson. "INFLUENCE OF GENDER ON GASTROCNEMIUS MUSCLE ACTIVITY DURING THE STANCE PHASE OF GAIT." Journal of Musculoskeletal Research 15, no. 02 (2012): 1250011. http://dx.doi.org/10.1142/s021895771250011x.
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Purpose: Differences in muscle activity have been observed between men and women in numerous lower extremity muscles in a variety of activities. These differences may be related to observed differences in the incidence of injuries between men and women. The purpose of this work is to determine if gender had an effect on the activity of the medial and lateral gastrocnemius muscles during the early part of the stance phase of gait. Method: An observational cohort study was set up using sixteen volunteers (9 men and 7 women, mean age = 27 years) with less than 5° of passive ankle-dorsiflexion range of motion. Maximum dorsiflexion, maximum knee flexion, stance time and EMG magnitude were measured for both men and women during early stance (heel strike to heel off). Results: EMG amplitude of the LG muscle in women was significantly higher than that of men. No significant differences were observed between men and women for maximum dorsiflexion, maximum knee flexion or stance time. Conclusions: A gender difference in gastrocnemius muscle EMG magnitude exists that is independent of knee and ankle kinematics and walking speed.
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Amankwah, Kofi, Ronald Triolo, Robert Kirsch, and Musa Audu. "A model-based study of passive joint properties on muscle effort during static stance." Journal of Biomechanics 39, no. 12 (2006): 2253–63. http://dx.doi.org/10.1016/j.jbiomech.2005.07.012.
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Zhang, Hongbo, Maury A. Nussbaum, and Michael J. Agnew. "A new method to assess passive and active ankle stiffness during quiet upright stance." Journal of Electromyography and Kinesiology 25, no. 6 (2015): 937–43. http://dx.doi.org/10.1016/j.jelekin.2015.10.011.
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Blaszczyk, JW, PD Hansen, and DL Lowe. "Accuracy of passive ankle joint positioning during quiet stance in young and elderly subjects." Gait & Posture 1, no. 4 (1993): 211–15. http://dx.doi.org/10.1016/0966-6362(93)90048-6.
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Yabuki-Soh, Noriko, and Yukiko Okuno. "Japanese L2 learners’ subjective construal: an analysis of expressions of emotion and evaluation in written storytelling found in I-JAS data." Journal of Japanese Linguistics 38, no. 1 (2022): 49–69. http://dx.doi.org/10.1515/jjl-2022-2050.
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Abstract Japanese is considered to be a language in which speakers tend to take a subjective stance by locating themselves within the situation they construe. Previous research indicates that in storytelling, Japanese L2 learners employ fewer expressions of viewpoint than L1 speakers do, and viewpoint tends to shift from character to character. Do Japanese L2 learners, then, typically take an objective stance, or do they use other devices to take a subjective stance? The present study compared Japanese L2 learners’ subjective construal with that of L1 speakers in two types of storytelling. The results indicated that while Japanese L1 speakers typically used passive voice to maintain a viewpoint, L2 learners employed a variety of expressions related to emotion and evaluation to subjectively describe the given events throughout each story. The study suggests the existence of interlanguage in that L2 learners use vocabulary-based devices instead of grammatical devices for subjective construal.
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Pihl, Connor, Bruce Sangeorzan, William Ledoux, Kylie Edinger, Ravi Balasubramanian, and Christina Stender. "Passive Engineering Mechanism Enhancement of a Flexor Digitorum Longus Tendon Transfer Procedure." Foot & Ankle Orthopaedics 2, no. 3 (2017): 2473011417S0003. http://dx.doi.org/10.1177/2473011417s000324.
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Category: Ankle, Basic Sciences/Biologics, Hindfoot, Midfoot/Forefoot Introduction/Purpose: Adult acquired flatfoot deformity (AAFD) associated with posterior tibial tendon (PTT) dysfunction remains a common orthopaedic problem for which a definitive solution has yet to be identified. Controversy has surrounded the diversity of treatment approaches utilized in current practice, which collectively fail to restore physiologic posterior tibial tendon function. In this proof-of-concept study we proposed a novel passive engineering mechanism (PEM) enhanced flexor digitorum longus (FDL) tendon transfer to address this deficiency. The objective of this study was to determine if PEM-enhancement would better restore physiologic PTT function and gait using a biomechanical flatfoot model. We hypothesized that compared to standard treatment, PEM-enhancement would increase applied FDL tendon force and improve pedobarographic and kinematic gait parameters. Methods: An AAFD model consistent with stage II PTT dysfunction was induced in 8 cadaveric lower-limb specimens. Specimens were tested using a robotic gait simulator (RGS) under conditions in randomized order simulating flatfoot, standard treatment, and PEM-enhanced treatment. Three trials were performed for each condition per specimen for a total of 120 trials. In PEM conditions, a custom pulley was fixed in series to the PT tendon along its normal line of action to provide biorealistic passive mechanical advantage (Fig. 1). Pedobarographic (plantar pressures and CoP) and foot bone kinematics during the stance phase of gait were assessed with a RGS-integrated pressure mat and motion capture system respectively. Twenty-five independent RGS trials were completed to measure PEM force scaling using a custom load cell. For statistical analysis, a linear mixed-effects regression was used to determine if mean biomechanical outcome differed by condition. Significance was set at p = 0.05. Results: Cadaveric flatfoot induction and robotic gait simulation produced a statistically validated biomechanical AAFD model. Throughout stance phase, PEM-enhancement significantly increased applied FDL tendon forces while reflecting physiologic tendon action, with mean FDL force increased 32.6 ± 10.7% at the physiologic force peak. Pedobarographic data demonstrated that PEM- enhancement consistently increased lateral pressure and decreased medial pressure during stance phase, with significantly decreased hindfoot pressure (-21 to -24 kPa) and laterally shifted CoP (3.9 to 4.8 mm) observed in comparison to standard treatment. Kinematic data generally showed that PEM-enhancement caused adduction, inversion, and elevation of the medial longitudinal arch during stance phase, with significant joint motion differences (~1 to 2 degrees) observed from standard treatment for the tibiotalar, naviculocuneiform, and first MTP. Conclusion: Using a well-documented biomechanical flatfoot model, we demonstrated that an innovative PEM-enhanced FDL tendon transfer better restored physiologic PTT force and gait characteristics compared to standard treatment. Further, PEM- enhancement enabled desired gait changes not previously observed in the literature for a modeled tendon transfer procedure, changes which compared to those found by other investigators who applied combined tendon transfer and bony procedures to achieve such results. These findings establish PEM-enhancement as a potential solution to PTT muscular imbalance following current surgical methods, and suggest that it may be a valuable feature of novel approaches to improve outcomes in AAFD treatment.
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Johanson, Marie A., Brian J. Cuda, Jonathan E. Koontz, Julia C. Stell, and Thomas A. Abelew. "Effect of Stretching on Ankle and Knee Angles and Gastrocnemius Activity during the Stance Phase of Gait." Journal of Sport Rehabilitation 18, no. 4 (2009): 521–34. http://dx.doi.org/10.1123/jsr.18.4.521.
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Context:Stretching exercises are commonly prescribed for patients and healthy individuals with limited extensibility of the gastrocnemius muscle.Objective:To determine effects of gastrocnemius stretching on ankle dorsiflexion, knee extension, and gastrocnemius muscle activity during gait.Design:Randomized-control trial.Setting:Biomechanical laboratory.Participants:Sixteen volunteers (9 men and 7 women, mean age = 27 y) with less than 5° of passive ankle-dorsiflexion range of motion randomly assigned to an experimental or control group.Intervention:The experimental group performed gastrocnemius stretching for 3 wk.Main Outcome Measures:Maximum ankle dorsiflexion, maximum knee extension, and EMG amplitude of the gastrocnemius muscles were measured between heel strike and heel-off before and after intervention.Results:No significant effect of group or time was found on maximum ankle dorsiflexion, maximum knee extension, or EMG activity of the medial or lateral gastrocnemius muscles between heel strike and heel-off. The experimental group had significantly greater passive ankle-dorsiflexion range of motion bilaterally at posttest than the control group.Conclusions:Stretching did not alter joint angles or gastrocnemius muscle activity in the early to midstance phase of gait.
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Usherwood, J. R., A. J. Channon, J. P. Myatt, J. W. Rankin, and T. Y. Hubel. "The human foot and heel–sole–toe walking strategy: a mechanism enabling an inverted pendular gait with low isometric muscle force?" Journal of The Royal Society Interface 9, no. 75 (2012): 2396–402. http://dx.doi.org/10.1098/rsif.2012.0179.
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Mechanically, the most economical gait for slow bipedal locomotion requires walking as an ‘inverted pendulum’, with: I, an impulsive, energy-dissipating leg compression at the beginning of stance; II, a stiff-limbed vault; and III, an impulsive, powering push-off at the end of stance. The characteristic ‘M’-shaped vertical ground reaction forces of walking in humans reflect this impulse–vault–impulse strategy. Humans achieve this gait by dissipating energy during the heel-to-sole transition in early stance, approximately stiff-limbed, flat-footed vaulting over midstance and ankle plantarflexion (powering the toes down) in late stance. Here, we show that the ‘M’-shaped walking ground reaction force profile does not require the plantigrade human foot or heel–sole–toe stance; it is maintained in tip–toe and high-heel walking as well as in ostriches. However, the unusual, stiff, human foot structure—with ground-contacting heel behind ankle and toes in front—enables both mechanically economical inverted pendular walking and physiologically economical muscle loading, by producing extreme changes in mechanical advantage between muscles and ground reaction forces. With a human foot, and heel–sole–toe strategy during stance, the shin muscles that dissipate energy, or calf muscles that power the push-off, need not be loaded at all—largely avoiding the ‘cost of muscle force’—during the passive vaulting phase.
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Jisa, Harriet, and Liliana Tolchinsky. "Developing a depersonalized stance through linguistic means in typologically different languages." Written Language and Literacy 12, no. 1 (2009): 1–25. http://dx.doi.org/10.1075/wll.12.1.01jis.
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Attaining rhetorical competence requires the capacity to use linguistic form to communicate discourse stance as well as discourse content. Languages provide their speakers with a range of options to express content in ways that reveal orientation, generality of reference, and attitude to the propositional content of their message to create a more involved or detached discourse stance. This paper focuses on the linguistic means used by children (9–10-, 12–13-, and 15–16-year olds) and university graduate students in French and Spanish in their attempt to create a detached discourse stance in expository texts. Two types of linguistic means for encoding discourse stance are examined: local devices which call for the manipulation of morphology and the lexicon, and phrase-level devices which require manipulation of argument structure. Our results show (1) that children in both languages are sensitive to the necessity of encoding a depersonalized discourse stance in expository texts early on; (2) that local devices are productive before those involving the rearrangement of argument structure; and (3) that with development and increasing interaction with academic texts the range of devices employed increases. The data reveal that for the phrase-level devices French speakers prefer passive constructions, while Spanish-speakers prefer se-constructions. Our results illustrate how later language development is influenced by language-specific facts and literacy interacting with universally shared communicative needs.
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Simonsen, Erik B., Katrine L. Cappelen, Ragnhild í. Skorini, Peter K. Larsen, Tine Alkjær, and Poul Dyhre-Poulsen. "Explanations Pertaining to the Hip Joint Flexor Moment During the Stance Phase of Human Walking." Journal of Applied Biomechanics 28, no. 5 (2012): 542–50. http://dx.doi.org/10.1123/jab.28.5.542.
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A hip joint flexor moment in the last half of the stance phase during walking has repeatedly been reported. However, the purpose of this moment remains uncertain and it is unknown how it is generated. Nine male subjects were instructed to walk at 4.5 km/h with their upper body in three different positions: normal, inclined and reclined. Net joint moments were calculated about the hip, knee and ankle joint. The peak hip joint flexor moment during late stance was significantly lower during inclined walking than in the two other conditions. During normal walking the iliacus muscle showed no or very weak activity and first at the transition from stance to swing. When walking reclined, a clear but rather low activity level of the iliacus muscle was seen in the first half of the stance phase, which could contribute to the hip moment. In the inclined condition the iliacus showed much increased activity but only in the swing phase. It is concluded that the hip flexor moment in question is largely generated by passive structures in the form of ligaments resisting hip joint extension.
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Bargdill, Richard W. "Toward a Theory of Habitual Boredom." Janus Head 13, no. 2 (2014): 93–111. http://dx.doi.org/10.5840/jh201413219.
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This article describes the experience of habitual boredom including: contrasting situational and habitual boredom, reviewing the humanistic-existential literature on habitual boredom as well as presenting a theory of habitual boredom. The theory suggests that habitual boredom develops from ambivalence (1) an emotional tear between one’s self and others. This ambivalence leads to a passive-avoidant stance (2) toward one’s life. This passivity includes a passive hope (3); the bored person believes something or someone else will change the bored person’s life, but not one’s own actions. Gradually, this passivity exposes identity confusion (4) but corrective action is thwarted because the person is too ashamed (5) to ask for help. Habitual boredom is conceptualized as an unresolved experience of personal meaninglessness.
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Kulkarni, Ashwini, Chuyi Cui, Shirley Rietdyk, and Satyajit Ambike. "Humans prioritize walking efficiency or walking stability based on environmental risk." PLOS ONE 18, no. 4 (2023): e0284278. http://dx.doi.org/10.1371/journal.pone.0284278.
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In human gait, the body’s mechanical energy at the end of one step is reused to achieve forward progression during the subsequent step, thereby reducing the required muscle work. During the single stance phase, humans rely on the largely uncontrolled passive inverted pendular motion of the body to perpetuate forward motion. These passive body dynamics, while improving walking efficiency, also indicate lower passive dynamic stability in the anterior direction, since the individual will be less able to withstand a forward external perturbation. Here we test the novel hypothesis that humans manipulate passive anterior-posterior (AP) stability via active selection of step length to either achieve energy-efficient gait or to improve stability when it is threatened. We computed the AP margin of stability, which quantifies the passive dynamic stability of gait, for multiple steps as healthy young adults (N = 20) walked on a clear and on an obstructed walkway. Participants used passive dynamics to achieve energy-efficient gait for all but one step; when crossing the obstacle with the leading limb, AP margin of stability was increased. This increase indicated caution to offset the greater risk of falling after a potential trip. Furthermore, AP margin of stability increased while approaching the obstacle, indicating that humans proactively manipulate the passive dynamics to meet the demands of the locomotor task. Finally, the step length and the center of mass motion co-varied to maintain the AP margin of stability for all steps in both tasks at the specific values for each step. We conclude that humans actively regulate step length to maintain specific levels of passive dynamic stability for each step during unobstructed and obstructed gait.
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Umberger, Brian R. "Stance and swing phase costs in human walking." Journal of The Royal Society Interface 7, no. 50 (2010): 1329–40. http://dx.doi.org/10.1098/rsif.2010.0084.
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Leg swing in human walking has historically been viewed as a passive motion with little metabolic cost. Recent estimates of leg swing costs are equivocal, covering a range from 10 to 33 per cent of the net cost of walking. There has also been a debate as to whether the periods of double-limb support during the stance phase dominate the cost of walking. Part of this uncertainty is because of our inability to measure metabolic energy consumption in individual muscles during locomotion. Therefore, the purpose of this study was to investigate the metabolic cost of walking using a modelling approach that allowed instantaneous energy consumption rates in individual muscles to be estimated over the full gait cycle. At a typical walking speed and stride rate, leg swing represented 29 per cent of the total muscular cost. During the stance phase, the double-limb and single-limb support periods accounted for 27 and 44 per cent of the total cost, respectively. Performing step-to-step transitions, which encompasses more than just the double-support periods, represented 37 per cent of the total cost of walking. Increasing stride rate at a constant speed led to greater double-limb support costs, lower swing phase costs and no change in single-limb support costs. Together, these results provide unique insight as to how metabolic energy is expended over the human gait cycle.
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Shamaei, Kamran, Paul C. Napolitano, and Aaron M. Dollar. "Design and Functional Evaluation of a Quasi-Passive Compliant Stance Control Knee–Ankle–Foot Orthosis." IEEE Transactions on Neural Systems and Rehabilitation Engineering 22, no. 2 (2014): 258–68. http://dx.doi.org/10.1109/tnsre.2014.2305664.
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Ati, Ali El, Islam Boussaada, Sami Tliba, and Silviu-Iulian Niculescu. "Analysis of an Active/Passive Postural Quiet Stance Regulation Model: Perfect Behavior and Critical Characteristics." IFAC-PapersOnLine 55, no. 40 (2022): 91–96. http://dx.doi.org/10.1016/j.ifacol.2023.01.054.
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Mitko, A. V., and V. K. Sidorov. "Native Canadian daily life in the Northwest Passage context." Arctic XXI century. Humanities, no. 4 (December 26, 2023): 134–46. http://dx.doi.org/10.25587/2310-5453-2023-4-134-146.
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This article explores the connection between the indigenous populations of the North and the Canadian government regarding the Northwest Passage in the Arctic region. The significance of indigenous representation in managing the Northwest Passage is emphasized. The challenges faced by small indigenous groups of the Canadian Arctic are addressed, as well as possible solutions through series of mutually beneficial economic and political proposals. Inuit involvement in the management of marine ecosystem goes beyond Canada’s borders. The Arctic Council has demonstrated that permanent participants from Northern Indigenous communities can significantly influence government, especially on Arctic issues. The days when the Arctic was on the outskirts of global political affairs are gone, as are the days of Canada’s previous passive stance towards its assertions of historically internal waters within the Northwest Passage. Advancing the interests of Indigenous peoples of the North is a well-established Canadian position. The utilization of the Arctic territory by these peoples serves as the backbone of Canada’s Arctic State Policy, consistently articulated by the Government of Canada.
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McGibbon, Chris A., and David E. Krebs. "Discriminating age and disability effects in locomotion: neuromuscular adaptations in musculoskeletal pathology." Journal of Applied Physiology 96, no. 1 (2004): 149–60. http://dx.doi.org/10.1152/japplphysiol.00422.2003.
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We identified biomechanical variables indicative of lower extremity dysfunction, distinct from age-related gait adaptations, and examined interrelationships among these variables to better understand the neuromuscular adaptations in gait. Sagittal plane ankle, knee, and hip peak angles, moments, and powers and spatiotemporal parameters were acquired during preferred-speed gait in 120 subjects: 45 healthy young, 37 healthy elders, and 38 elders with functional limitations due to lower extremity musculoskeletal pathology, primarily arthritis. Multiple analysis of covariance with discriminate analysis, adjusted for gait speed, was used to identify the variables discriminating groups. Correlation analysis was used to explore interrelationships among these variables within each group. Healthy elders were discriminated (sensitivity 76%, specificity 82%) from young adults via decreased late-stance ankle plantar flexion angle, increased late-stance knee power absorption, and early-stance hip extensor power generation. Disabled elders were discriminated (sensitivity 74%, specificity 73%) from healthy elders via decreased late-stance ankle plantar flexor moment and power generation, increased early-stance ankle dorsiflexor moment, and late-stance hip flexor moment and power absorption. Relationships among variables showed a higher degree of coupling for the disabled elders compared with the healthy groups, suggesting a reduced ability to alter motor strategies. Our data suggest that, beyond age-related changes, elders with lower extremity dysfunction rely excessively on passive action of hip flexors to provide propulsion in late stance and contralateral ankle dorsiflexors to enhance stability. These findings support a growing body of evidence that gait changes with age and disablement have a neuromuscular basis, which may be informative in a motor control framework for physical therapy interventions.
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Garikayi, Talon, Dawie Van Den Heever, and Stephen Matope. "INVESTIGATING THE EFFECTS OF PASSIVE MECHANICAL ANKLE ON UNILATERAL OSTEOMYOPLASTIC TRANSTIBIAL AMPUTEES." Journal of Musculoskeletal Research 20, no. 03 (2017): 1750015. http://dx.doi.org/10.1142/s0218957717500154.
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Purpose The study presents an investigation of the asymmetries in normal gait associated with the use of prosthetic mechanical passive ankle devices when performing ambulatory-related activities for unilateral osteomyoplastic transtibial amputees. Asymmetries in gait may lead to low-back pain and other long-term effects associated with hip compensation and excessive energy consumption. Methods Unilateral transtibial osteomyoplastic amputees were tasked to perform normal gait. The Vicon Motion system and Myomotion System consisting of electromyography sensors and inertial measurement units were used to collect data. Quantitative gait analysis was used for the analysis of anatomical angles for the ankle, knee, hip and pelvis. The results were compared to normative data. Result It was hypothesized that the unilateral amputees would demonstrate high peaks on the hip, knee and ankle of the intact side so as to compensate for the lack of propulsive force on the passive ankle of the prosthetic limb. All parameters for anatomical angles were found to be significant ([Formula: see text]), hip flexion ([Formula: see text]), knee flexion ([Formula: see text]) and ankle dorsiflexion ([Formula: see text]). Temporal and distance variables were quantitatively analyzed and there was no significant difference. Poor management of range of motion was observed on the ankle and the knee. There was minimum hip extension during the stance phase. There was excessive hip rotation and foot plantarflexion on the intact side of the amputee as hip compensation was being applied during the toe-off period and early swing. Amputees exhibited short stance time duration. Conclusion This study demonstrated that amputees can achieve same distance variables as normal subjects; however, this causes variations in anatomical angles which result in asymmetries in normal gait. Variations in lateral pelvic tilt indicated possible development of lower back pain and changes in posture.
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Burn, Jeremy F., and Steven J. Usmar. "Hoof landing velocity is related to track surface properties in trotting horses." Equine and Comparative Exercise Physiology 2, no. 1 (2005): 37–41. http://dx.doi.org/10.1079/ecp200542.
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AbstractThe resistance of a track surface to deformation is known to be positively related to the magnitude of foot impact experienced during locomotion. Although passive mechanics suggests that this might be entirely due to the action of the track surface material decelerating the foot, it is also possible that the dynamics of locomotion are altered in a way that changes the landing velocity of the foot. The observed relationship between track properties and foot impact would then be due to a combination of the direct effect of the surface material and altered foot kinematics at impact. In this study we measured hoof landing velocity, stance time and limb landing angle in horses trotting over surfaces that differed significantly in their deformability. In comparison with a surface that underwent negligible deformation during stance phase, a surface that deformed 25 mm led to significantly increased stance time, significantly greater leg landing angle and significantly greater hoof landing velocity. Although the increased hoof landing velocity would act to counteract the increased shock absorption on the softer surface, we suggest that this effect is relatively small.
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Huq, M. Saiful, and M. O. Tokhi. "Development of a Novel Fully Passive Treadmill Training Paradigm for Lower Limb Therapeutic Intervention." Applied Bionics and Biomechanics 10, no. 2-3 (2013): 97–111. http://dx.doi.org/10.1155/2013/782016.
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A simulation based study of a completely new form of body-weight supported treadmill training (BWSTT) technique which is fully passive in nature is presented in this paper. The approach does not require any powered means at the lower limbs and is implemented using a combination of coordinated joint locking/unlocking and flexible torque transfer mechanisms. The hip extension pertaining to the stance phase of the gait cycle is achieved through the stance foot being literally dragged by the treadmill belt while the required manoeuvring of the trunk is expected to be accomplished by the voluntary arm-support from the subject. The swing phase, on the other hand, is initiated through appropriately coupling the swing knee with the contralateral extending hip and eventually achieve full knee extension through switching the treadmill speed to a lower value. Considering adequate support from the able arms, the process effectively turns the frictional force at the foot-treadmill belt interface into an agent causing the required whole body mechanical energy fluctuation during the gait cycle.The simulation platform consists of a dynamic planer (sagittal) full body humanoid model along with the treadmill model developed within a CAD based software environment interfaced with passive viscoelastic joint properties implemented in Simulink. The voluntary upper body effort as well as control of the gait cycle are also developed within MATLAB/Simulink environment. The gait cycle generated using the new concept is thoroughly investigated through this simulation study.
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Garcia, Mariano, Anindya Chatterjee, Andy Ruina, and Michael Coleman. "The Simplest Walking Model: Stability, Complexity, and Scaling." Journal of Biomechanical Engineering 120, no. 2 (1998): 281–88. http://dx.doi.org/10.1115/1.2798313.
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We demonstrate that an irreducibly simple, uncontrolled, two-dimensional, two-link model, vaguely resembling human legs, can walk down a shallow slope, powered only by gravity. This model is the simplest special case of the passive-dynamic models pioneered by McGeer (1990a). It has two rigid massless legs hinged at the hip, a point-mass at the hip, and infinitesimal point-masses at the feet. The feet have plastic (no-slip, no-bounce) collisions with the slope surface, except during forward swinging, when geometric interference (foot scuffing) is ignored. After nondimensionalizing the governing equations, the model has only one free parameter, the ramp slope γ. This model shows stable walking modes similar to more elaborate models, but allows some use of analytic methods to study its dynamics. The analytic calculations find initial conditions and stability estimates for period-one gait limit cycles. The model exhibits two period-one gait cycles, one of which is stable when 0 < γ < 0.015 rad. With increasing γ stable cycles of higher periods appear, and the walking-like motions apparently become chaotic through a sequence of period doublings. Scaling laws for the model predict that walking speed is proportional to stance angle, stance angle is proportional to γ1/3, and that the gravitational power used is proportional to ν4 where ν is the velocity along the slope.
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Kochanska, Grazyna, Sanghag Kim, and Lea J. Boldt. "(Positive) power to the child: The role of children's willing stance toward parents in developmental cascades from toddler age to early preadolescence." Development and Psychopathology 27, no. 4pt1 (2015): 987–1005. http://dx.doi.org/10.1017/s0954579415000644.
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AbstractIn a change from the once-dominant view of children as passive in the parent-led process of socialization, children are now seen as active agents who can considerably influence that process. However, these newer perspectives typically focus on the child's antagonistic influence, due either to a difficult temperament or aversive, resistant, negative behaviors that elicit adversarial responses from the parent and lead to future coercive cascades in the relationship. Children's capacity to act as receptive, willing, even enthusiastic, active socialization agents is largely overlooked. Informed by attachment theory and other relational perspectives, we depict children as able to adopt an active willing stance and to exert robust positive influence in the mutually cooperative socialization enterprise. A longitudinal study of 100 community families (mothers, fathers, and children) demonstrates that willing stance (a) is a latent construct, observable in diverse parent–child contexts, parallel at 38, 52, and 67 months and longitudinally stable; (b) originates within an early secure parent–child relationship at 25 months; and (c) promotes a positive future cascade toward adaptive outcomes at age 10. The outcomes include the parent's observed and child-reported positive, responsive behavior, as well as child-reported internal obligation to obey the parent and parent-reported low level of child behavior problems. The construct of willing stance has implications for basic research in typical socialization and in developmental psychopathology as well as for prevention and intervention.
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Thomas, Kristie. "China and the WTO Dispute Settlement System: From Passive Observer to Active Participant?" Global Trade and Customs Journal 6, Issue 10 (2011): 481–90. http://dx.doi.org/10.54648/gtcj2011060.
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Since China's accession to the World Trade Organization (WTO) in December 2001, it has participated in a relatively small number of cases brought to the WTO Dispute Settlement Body (DSB), contrary to the many wild predictions made prior to entry. In the first few years post-accession, China seemed content to act as a passive observer, participating mainly as a third party. However, since 2006, there appears to have been a shift in attitude with China now taking a more combative stance, particularly in the past few years. This article will examine China's participation in the WTO DSB from 2002 to date to explore whether China's approach really has shifted from that of passive observer to that of an active participant, possible reasons to explain this transformation and what the implications of such a shift may be for other WTO Contracting Parties.
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Kikuchi, Takayuki, Ryota Fujino, Kenta Igarashi, and Koichi Koganezawa. "Non-Energized Above Knee Prosthesis Enabling Stairs Ascending and Descending with Hydraulic Flow Controller." Journal of Robotics and Mechatronics 30, no. 6 (2018): 892–99. http://dx.doi.org/10.20965/jrm.2018.p0892.
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This paper deals with an above-knee prosthesis (AKP) that allows stair ascending/descending with no external energy source. It controls the passive resistance and interlocking strength of the knee and ankle joints with a flow control valve (FCV) equipped with a hydraulic system. The FCV is also mechanically controlled by an automatic flow controller (AFC). Our previous study certified that the experimental AKP allows step-over-step gait in stair ascending and a slight knee flexion at the initial stage of the stance phase in level ground walking, as observed from non-amputees’ walking. However, the experiments showed that the AKP does not allow smooth flexing of the knee in the stance phase during stairs descending because of the improper timing of the AFC opening. This paper shows the total walking performance of the AKP equipped with a refined AFC.
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Frey Law, Laura A., and Richard K. Shields. "Femoral loads during passive, active, and active–resistive stance after spinal cord injury: a mathematical model." Clinical Biomechanics 19, no. 3 (2004): 313–21. http://dx.doi.org/10.1016/j.clinbiomech.2003.12.005.
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