Articoli di riviste: "Gait in humans"

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Kale, A., A. Sundaresan, A. N. Rajagopalan, N. P. Cuntoor, A. K. Roy-Chowdhury, V. Kruger e R. Chellappa. "Identification of Humans Using Gait". IEEE Transactions on Image Processing 13, n. 9 (settembre 2004): 1163–73. http://dx.doi.org/10.1109/tip.2004.832865.

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Usherwood, James R., e John E. A. Bertram. "Gait transition cost in humans". European Journal of Applied Physiology 90, n. 5-6 (1 novembre 2003): 647–50. http://dx.doi.org/10.1007/s00421-003-0980-6.

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Wu, Chang Wei, e Hua Deng. "Gait Generation of Humanoid Robot Based on Analysis of the Human's Gait". Applied Mechanics and Materials 513-517 (febbraio 2014): 3453–58. http://dx.doi.org/10.4028/www.scientific.net/amm.513-517.3453.

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In this paper, a method to generate the humanoid robots gait intelligently is put forward to solve the problem of poor performance of robot walking. The key idea in this proposed method is to adapt the transmutative humans gait to robot walking. Firstly, the character of the humans gait is acquired by researching a mass of gait data. Then, the typical gait signal is obtained which can be used to generate various gait signals. Finally, this method is proved to be effective by comparing the nature signals and the signal which is obtained by this method.

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Huang, P. S., C. J. Harris e M. S. Nixon. "Recognising humans by gait via parametric canonical space". Artificial Intelligence in Engineering 13, n. 4 (ottobre 1999): 359–66. http://dx.doi.org/10.1016/s0954-1810(99)00008-4.

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Sinkjaer, T., J. B. Andersen e B. Larsen. "Soleus stretch reflex modulation during gait in humans". Journal of Neurophysiology 76, n. 2 (1 agosto 1996): 1112–20. http://dx.doi.org/10.1152/jn.1996.76.2.1112.

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1. The modulation of the short-latency stretch reflex during walking at different walking speeds was investigated and compared with the stretch reflex during standing in healthy human subjects. 2. Ankle joint stretches were applied by a system able to rotate the human ankle joint during treadmill walking in any phase of the step cycle. The system consisted of a mechanical joint attached to the subject's ankle joint and connected to a motor placed beside the treadmill by means of bowden wires. The weight of the total system attached to the leg of the subject was 900 g. 3. The short-latency soleus stretch reflex was modulated during a step. In the stance phase, the amplitude equaled that found during standing at matched soleus background electromyogram (EMG). In the transition from stance to swing, the amplitude was 0 in all subjects. In late swing, the stretch reflex amplitude increased to 45 +/- 27% (mean +/- SD) of the maximal amplitude in the stance phase (stretch amplitude 8 degrees, stretch velocity 250 degrees/s). 4. The onset (42 +/- 3.2 ms) and peak latencies (59 +/- 2.5 ms) of the stretch reflex did not depend on the phase in the step cycle at which the reflex was elicited. 5. When the ankle joint is rotated, a change in torque can be measured. The torque measured over the first 35 ms after stretch onset (nonreflex torque) was at a maximum during late stance, when the leg supported a large part of the body's weight, and at a minimum during the swing phase. At heel contact the nonreflex torque was 50% of its maximal value. 6. During the stance phase the maximal EMG stretch reflex had a phase lead of approximately 120 ms with respect to the maximal background EMG and a phase lead of approximately 250 ms with respect to the maximal nonreflex torque. 7. The constant latency of the stretch reflex during a step implied that the ankle extensor muscle spindles are always taut during walking. 8. The relatively high amplitude of the stretch reflex in late swing and at heel contact made it likely that the stretch reflex contributed to the activation of the ankle extensor muscles in early stance phase.

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Corporaal, Sharissa H. A., Stephan P. Swinnen, Jacques Duysens e Sjoerd M. Bruijn. "Slow maturation of planning in obstacle avoidance in humans". Journal of Neurophysiology 115, n. 1 (1 gennaio 2016): 404–12. http://dx.doi.org/10.1152/jn.00701.2015.

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Complex gait (e.g., obstacle avoidance) requires a higher cognitive load than simple steady-state gait, which is a more automated movement. The higher levels of the central nervous system, responsible for adjusting motor plans to complex gait, develop throughout childhood into adulthood. Therefore, we hypothesize that gait strategies in complex gait are likely to mature until adulthood as well. However, little is known about the maturation of complex gait from childhood into adolescence and adulthood. To address this issue, we investigated obstacle avoidance in forty-four 8- to 18-yr-old participants who walked at preferred speed along a 6-m walkway on which a planar obstacle (150% of step length, 1 m wide) was projected. Participants avoided the obstacle by stepping over this projection, while lower body kinematics were recorded. Results showed that step length and speed adjustments during successful obstacle avoidance were similar across all ages, even though younger children modified step width to a greater extent. Additionally, the younger children used larger maximal toe elevations and take-off distances than older children. Moreover, during unsuccessful trials, younger children deployed exaggerated take-off distances, which resulted in obstacle contact upon the consecutive heel strike. These results indicate that obstacle avoidance is not fully matured in younger children, and that the inability to plan precise foot placements is an important factor contributing to failures in obstacle avoidance.

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Verlinden, Vincentius J. A., Marius de Groot, Lotte G. M. Cremers, Jos N. van der Geest, Albert Hofman, Wiro J. Niessen, Aad van der Lugt, Meike W. Vernooij e M. Arfan Ikram. "Tract-specific white matter microstructure and gait in humans". Neurobiology of Aging 43 (luglio 2016): 164–73. http://dx.doi.org/10.1016/j.neurobiolaging.2016.04.005.

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Biewener, Andrew A., e Jae Chang. "Gait related changes in limb mechanical advantage in humans". Journal of Biomechanics 26, n. 3 (marzo 1993): 294. http://dx.doi.org/10.1016/0021-9290(93)90395-u.

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Samangooei, Sina, e Mark S. Nixon. "Performing content-based retrieval of humans using gait biometrics". Multimedia Tools and Applications 49, n. 1 (22 ottobre 2009): 195–212. http://dx.doi.org/10.1007/s11042-009-0391-8.

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Yamano, Junsei, Masaki Kurokawa, Yuki Sakai e Kenji Hashimoto. "Realization of a Human-like Gait for a Bipedal Robot Based on Gait Analysis". Machines 12, n. 2 (25 gennaio 2024): 92. http://dx.doi.org/10.3390/machines12020092.

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There are many studies analyzing human motion. However, we do not yet fully understand the mechanisms of our own bodies. We believe that mimicking human motion and function using a robot will help us to deepen our understanding of humans. Therefore, we focus on the characteristics of the human gait, and the goal is to realize a human-like bipedal gait that lands on its heels and takes off from its toes. In this study, we focus on kinematic synergy (planar covariation) in the lower limbs as a characteristic gait seen in humans. Planar covariation is that elevation angles at the thigh, shank, and foot in the sagittal plane are plotted on one plane when the angular data are plotted on the three axes. We propose this feature as a reward for reinforcement learning. By introducing this reward, the bipedal robot achieved a human-like bipedal gait in which the robot lands on its heels and takes off from its toes. We also compared the learning results with those obtained when this feature was not used. The results suggest that planar covariation is one factor that characterizes a human-like gait.

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Lee, David V., Tudor N. Comanescu, Michael T. Butcher e John E. A. Bertram. "A comparative collision-based analysis of human gait". Proceedings of the Royal Society B: Biological Sciences 280, n. 1771 (22 novembre 2013): 20131779. http://dx.doi.org/10.1098/rspb.2013.1779.

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This study compares human walking and running, and places them within the context of other mammalian gaits. We use a collision-based approach to analyse the fundamental dynamics of the centre of mass (CoM) according to three angles derived from the instantaneous force and velocity vectors. These dimensionless angles permit comparisons across gait, species and size. The collision angle Φ , which is equivalent to the dimensionless mechanical cost of transport CoT mech , is found to be three times greater during running than walking of humans. This threefold difference is consistent with previous studies of walking versus trotting of quadrupeds, albeit tends to be greater in the gaits of humans and hopping bipeds than in quadrupeds. Plotting the collision angle Φ together with the angles of the CoM force vector Θ and velocity vector Λ results in the functional grouping of bipedal and quadrupedal gaits according to their CoM dynamics—walking, galloping and ambling are distinguished as separate gaits that employ collision reduction, whereas trotting, running and hopping employ little collision reduction and represent more of a continuum that is influenced by dimensionless speed. Comparable with quadrupedal mammals, collision fraction (the ratio of actual to potential collision) is 0.51 during walking and 0.89 during running, indicating substantial collision reduction during walking, but not running, of humans.

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Granatosky, Michael C., Caleb M. Bryce, Jandy Hanna, Aidan Fitzsimons, Myra F. Laird, Kelsey Stilson, Christine E. Wall e Callum F. Ross. "Inter-stride variability triggers gait transitions in mammals and birds". Proceedings of the Royal Society B: Biological Sciences 285, n. 1893 (12 dicembre 2018): 20181766. http://dx.doi.org/10.1098/rspb.2018.1766.

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Speed-related gait transitions occur in many animals, but it remains unclear what factors trigger gait changes. While the most widely accepted function of gait transitions is that they reduce locomotor costs, there is no obvious metabolic trigger signalling animals when to switch gaits. An alternative approach suggests that gait transitions serve to reduce locomotor instability. While there is evidence supporting this in humans, similar research has not been conducted in other species. This study explores energetics and stride variability during the walk–run transition in mammals and birds. Across nine species, energy savings do not predict the occurrence of a gait transition. Instead, our findings suggest that animals trigger gait transitions to maintain high locomotor rhythmicity and reduce unstable states. Metabolic efficiency is an important benefit of gait transitions, but the reduction in dynamic instability may be the proximate trigger determining when those transitions occur.

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Choi, Sang-Il, Jucheol Moon, Hee-Chan Park e Sang Tae Choi. "User Identification from Gait Analysis Using Multi-Modal Sensors in Smart Insole". Sensors 19, n. 17 (31 agosto 2019): 3785. http://dx.doi.org/10.3390/s19173785.

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Recent studies indicate that individuals can be identified by their gait pattern. A number of sensors including vision, acceleration, and pressure have been used to capture humans’ gait patterns, and a number of methods have been developed to recognize individuals from their gait pattern data. This study proposes a novel method of identifying individuals using null-space linear discriminant analysis on humans’ gait pattern data. The gait pattern data consists of time series pressure and acceleration data measured from multi-modal sensors in a smart insole used while walking. We compare the identification accuracies from three sensing modalities, which are acceleration, pressure, and both in combination. Experimental results show that the proposed multi-modal features identify 14 participants with high accuracy over 95% from their gait pattern data of walking.

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Wang, ChiHong, YauYau Wai, BoCheng Kuo, Yei-Yu Yeh e JiunJie Wang. "Cortical control of gait in healthy humans: an fMRI study". Journal of Neural Transmission 115, n. 8 (28 maggio 2008): 1149–58. http://dx.doi.org/10.1007/s00702-008-0058-z.

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Catherine, Flaviana, e Risti Suryantari. "Gait Analysis Study of Runner Using Force Plate". INDONESIAN JOURNAL OF APPLIED PHYSICS 6, n. 02 (28 febbraio 2017): 125. http://dx.doi.org/10.13057/ijap.v6i02.2394.

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<pre>Humans do regular physical activities such as running. Gait is forward propulsion of the human body using lower extremities as a thrust. Humans gait pattern is characterized by their limbs movement in terms of velocity, ground reaction force, work, kinetic energy and potential energy cycle . Human gait analysis is used to assess, to plan, and to deliver the treatment for individuals based on the conditions that affect their ability to move. Gait analysis is commonly used in running sport to improve the efficiency of athletes in running and to identify problems related to their posture or movement. The aim of this research is to do running gait analysis study of human, using force plate which equipped by track board. The benefit of this study is to provide information, ideas and new perspectives about running and its prevention over an injury. The main method that will be discussed in this study is system design of gait analysis with specific setting, hardware and software, in order to acquire data(s). </pre>

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Summerside, Erik M., Rodger Kram e Alaa A. Ahmed. "Contributions of metabolic and temporal costs to human gait selection". Journal of The Royal Society Interface 15, n. 143 (giugno 2018): 20180197. http://dx.doi.org/10.1098/rsif.2018.0197.

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Humans naturally select several parameters within a gait that correspond with minimizing metabolic cost. Much less is understood about the role of metabolic cost in selecting between gaits. Here, we asked participants to decide between walking or running out and back to different gait specific markers. The distance of the walking marker was adjusted after each decision to identify relative distances where individuals switched gait preferences. We found that neither minimizing solely metabolic energy nor minimizing solely movement time could predict how the group decided between gaits. Of our twenty participants, six behaved in a way that tended towards minimizing metabolic energy, while eight favoured strategies that tended more towards minimizing movement time. The remaining six participants could not be explained by minimizing a single cost. We provide evidence that humans consider not just a single movement cost, but instead a weighted combination of these conflicting costs with their relative contributions varying across participants. Individuals who placed a higher relative value on time ran faster than individuals who placed a higher relative value on metabolic energy. Sensitivity to temporal costs also explained variability in an individual's preferred velocity as a function of increasing running distance. Interestingly, these differences in velocity both within and across participants were absent in walking, possibly due to a steeper metabolic cost of transport curve. We conclude that metabolic cost plays an essential, but not exclusive role in gait decisions.

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Bair, Woei-Nan, Michael Petr, Irene Alfaras, Sarah J. Mitchell, Michel Bernier, Luigi Ferrucci, Stephanie A. Studenski e Rafael De Cabo. "Of Aging Mice and Men: Gait Speed Decline Is a Translatable Trait, With Species-Specific Underlying Properties". Journals of Gerontology: Series A 74, n. 9 (14 gennaio 2019): 1413–16. http://dx.doi.org/10.1093/gerona/glz015.

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Abstract In the last two decades, great strides were made in our ability to extend the life span of model organisms through dietary and other manipulations. Survival curves provide evidence of altered aging processes but are uninformative on what lead to that increase in life span. Longitudinal assessments of health and function during intervention studies could help in the identification of predictive biomarkers for health and survival. Comparable biomarkers of healthspan are necessary to effectively translate interventions into human clinical trials. Gait speed is a well-established predictive biomarker of healthspan in humans for risk of disability, health outcomes and mortality, and is relatively simple to assess noninvasively in rodents. In this study, we assessed and compared gait speed in males from two species (mice and humans), from young adulthood to advanced old age. Although gait speed decreases nonlinearly with age in both species, the underlying drivers of this change in gait speed were different, with humans exhibiting a shortened step length, and mice displaying a decrease in cadence. Future longitudinal and interventional studies in mice should examine the predictive value of longitudinal declines in gait speed for health and survival.

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Kulkarni, Ashwini, Chuyi Cui, Shirley Rietdyk e Satyajit Ambike. "Humans prioritize walking efficiency or walking stability based on environmental risk". PLOS ONE 18, n. 4 (7 aprile 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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Sekhar, Rajagopal V., Premranjan Kumar, Jean W. Hsu, James Suliburk, George E. Taffet, Charles G. Minard, Farook Jahoor e Chun Liu. "CORRECTING GLUTATHIONE DEFICIENCY AND MITOCHONDRIAL DYSFUNCTION IN OLDER HUMANS: A RANDOMIZED CLINICAL TRIAL". Innovation in Aging 3, Supplement_1 (novembre 2019): S416. http://dx.doi.org/10.1093/geroni/igz038.1552.

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Abstract Aging is associated with impaired mitochondrial fatty-acid oxidation (MFO) due to unknown mechanisms, and interventions are lacking. We hypothesized that impaired MFO in aging occurs due to Glutathione-deficiency and tested this in a randomized, placebo-controlled double-blind clinical-trial in 24 older-humans (71.1y) and 12 young-controls (25.5y) using calorimetry, muscle-biopsy and tracer-protocols. Older-humans received either GlyNAC (Glycine 1.33mmol/kg/d and N-acetylcysteine 0.83mmol/kg/d as Glutathione precursors) or isonitrogenous-placebo for 16-weeks; young-controls received GlyNAC for 2-weeks. Compared to young-controls, older humans had significantly lower Glutathione, impaired MFO, lower gait-speed and physical-function, and higher oxidative-stress, inflammation and insulin-resistance. GlyNAC supplementation in older-humans significantly improved and restored MFO; increased gait-speed (19%,) and physical-function; and decreased oxidative-stress (TBARS 80%), inflammation (IL-6 83%; TNF-alpha 58%), and insulin-resistance (HOMA-IR 68%), but young-controls were unaffected. These data provide proof-of-concept that GlyNAC supplementation could improve the health of older-humans by correcting Glutathione-deficiency and mitochondrial-defects to improve gait-speed, oxidative-stress, inflammation and insulin-resistance.

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Sipari, Dario, Betsy D. M. Chaparro-Rico e Daniele Cafolla. "SANE (Easy Gait Analysis System): Towards an AI-Assisted Automatic Gait-Analysis". International Journal of Environmental Research and Public Health 19, n. 16 (14 agosto 2022): 10032. http://dx.doi.org/10.3390/ijerph191610032.

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The gait cycle of humans may be influenced by a range of variables, including neurological, orthopedic, and pathological conditions. Thus, gait analysis has a broad variety of applications, including the diagnosis of neurological disorders, the study of disease development, the assessment of the efficacy of a treatment, postural correction, and the evaluation and enhancement of sport performances. While the introduction of new technologies has resulted in substantial advancements, these systems continue to struggle to achieve a right balance between cost, analytical accuracy, speed, and convenience. The target is to provide low-cost support to those with motor impairments in order to improve their quality of life. The article provides a novel automated approach for motion characterization that makes use of artificial intelligence to perform real-time analysis, complete automation, and non-invasive, markerless analysis. This automated procedure enables rapid diagnosis and prevents human mistakes. The gait metrics obtained by the two motion tracking systems were compared to show the effectiveness of the proposed methodology.

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Ballard, Richard E., Donald E. Watenpaugh, Gregory A. Breit, Gita Murthy, Daniel C. Holley e Alan R. Hargens. "Leg intramuscular pressures during locomotion in humans". Journal of Applied Physiology 84, n. 6 (1 giugno 1998): 1976–81. http://dx.doi.org/10.1152/jappl.1998.84.6.1976.

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To assess the usefulness of intramuscular pressure (IMP) measurement for studying muscle function during gait, IMP was recorded in the soleus and tibialis anterior muscles of 10 volunteers during treadmill walking and running by using transducer-tipped catheters. Soleus IMP exhibited single peaks during late-stance phase of walking [181 ± 69 (SE) mmHg] and running (269 ± 95 mmHg). Tibialis anterior IMP showed a biphasic response, with the largest peak (90 ± 15 mmHg during walking and 151 ± 25 mmHg during running) occurring shortly after heel strike. IMP magnitude increased with gait speed in both muscles. Linear regression of soleus IMP against ankle joint torque obtained by a dynamometer produced linear relationships ( n = 2, r = 0.97 for both). Application of these relationships to IMP data yielded estimated peak soleus moment contributions of 0.95–1.65 N ⋅ m/kg during walking, and 1.43–2.70 N ⋅ m/kg during running. Phasic elevations of IMP during exercise are probably generated by local muscle tissue deformations due to muscle force development. Thus profiles of IMP provide a direct, reproducible index of muscle function during locomotion in humans.

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Ceccato, Jean-Charles, Mathieu de Sèze, Christine Azevedo e Jean-René Cazalets. "Comparison of Trunk Activity during Gait Initiation and Walking in Humans". PLoS ONE 4, n. 12 (7 dicembre 2009): e8193. http://dx.doi.org/10.1371/journal.pone.0008193.

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Huang, P. S., C. J. Harris e M. S. Nixon. "Visual Surveillance and Tracking of Humans by Face and Gait Recognition". IFAC Proceedings Volumes 31, n. 29 (ottobre 1998): 43–44. http://dx.doi.org/10.1016/s1474-6670(17)38339-8.

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Huang, Ping S., Chris J. Harris e Mark S. Nixon. "Visual Surveillance and Tracking of Humans by Face and Gait Recognition". IFAC Proceedings Volumes 31, n. 29 (ottobre 1998): 113–18. http://dx.doi.org/10.1016/s1474-6670(17)38931-0.

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Schniepp, Roman, Ken Möhwald e Max Wuehr. "Gait ataxia in humans: vestibular and cerebellar control of dynamic stability". Journal of Neurology 264, S1 (10 aprile 2017): 87–92. http://dx.doi.org/10.1007/s00415-017-8482-3.

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Molinari, Marco. "Plasticity properties of CPG circuits in humans: Impact on gait recovery". Brain Research Bulletin 78, n. 1 (gennaio 2009): 22–25. http://dx.doi.org/10.1016/j.brainresbull.2008.02.030.

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Okazaki, Suzuyo, Suetaka Nishiike, Hiroshi Watanabe, Takao Imai, Atsuhiko Uno, Tadashi Kitahara, Arata Horii et al. "Effects of repeated optic flow stimulation on gait termination in humans". Acta Oto-Laryngologica 133, n. 3 (26 novembre 2012): 246–52. http://dx.doi.org/10.3109/00016489.2012.740163.

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FRANK, T. D. "A SYNERGETIC GAIT TRANSITION MODEL FOR HYSTERETIC GAIT TRANSITIONS FROM WALKING TO RUNNING". Journal of Biological Systems 24, n. 01 (marzo 2016): 51–61. http://dx.doi.org/10.1142/s0218339016500030.

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Abstract (sommario):

A model for gait transitions from walking to running is proposed. The model is based on the theory of pattern formation and synergetics. Walking and running are considered as spatiotemporal patterns, while walk-to-run and run-to-walk transitions are regarded as bifurcations. Consequently, the model is cast in the form of coupled amplitude equations as known in the literature on pattern formation. It is shown that the model can reproduce hysteretic gait transitions that have been observed in experimental studies with humans walking on treadmills when locomotion speed is gradually increased and decreased. The control parameter is an appropriately rescaled velocity measure, the so-called Froude number, which is a body-scaled parameter that takes leg length into account. It is shown that the model can reproduce observed gait transitions for individuals and populations. In particular, probabilistic functions describing gait transitions on the population level can be defined that resemble the experimentally determined probabilistic function.

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Bruijn, Sjoerd M., e Jaap H. van Dieën. "Control of human gait stability through foot placement". Journal of The Royal Society Interface 15, n. 143 (giugno 2018): 20170816. http://dx.doi.org/10.1098/rsif.2017.0816.

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During human walking, the centre of mass (CoM) is outside the base of support for most of the time, which poses a challenge to stabilizing the gait pattern. Nevertheless, most of us are able to walk without substantial problems. In this review, we aim to provide an integrative overview of how humans cope with an underactuated gait pattern. A central idea that emerges from the literature is that foot placement is crucial in maintaining a stable gait pattern. In this review, we explore this idea; we first describe mechanical models and concepts that have been used to predict how foot placement can be used to control gait stability. These concepts, such as for instance the extrapolated CoM concept, the foot placement estimator concept and the capture point concept, provide explicit predictions on where to place the foot relative to the body at each step, such that gait is stabilized. Next, we describe empirical findings on foot placement during human gait in unperturbed and perturbed conditions. We conclude that humans show behaviour that is largely in accordance with the aforementioned concepts, with foot placement being actively coordinated to body CoM kinematics during the preceding step. In this section, we also address the requirements for such control in terms of the sensory information and the motor strategies that can implement such control, as well as the parts of the central nervous system that may be involved. We show that visual, vestibular and proprioceptive information contribute to estimation of the state of the CoM. Foot placement is adjusted to variations in CoM state mainly by modulation of hip abductor muscle activity during the swing phase of gait, and this process appears to be under spinal and supraspinal, including cortical, control. We conclude with a description of how control of foot placement can be impaired in humans, using ageing as a primary example and with some reference to pathology, and we address alternative strategies available to stabilize gait, which include modulation of ankle moments in the stance leg and changes in body angular momentum, such as rapid trunk tilts. Finally, for future research, we believe that especially the integration of consideration of environmental constraints on foot placement with balance control deserves attention.

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Hanisch, Simon, Evelyn Muschter, Admantini Hatzipanayioti, Shu-Chen Li e Thorsten Strufe. "Understanding Person Identification Through Gait". Proceedings on Privacy Enhancing Technologies 2023, n. 1 (gennaio 2023): 177–89. http://dx.doi.org/10.56553/popets-2023-0011.

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Abstract (sommario):

Gait recognition is the process of identifying humans from their bipedal locomotion such as walking or running. As such, gait data is privacy sensitive information and should be anonymized where possible. With the rise of higher quality gait recording techniques, such as depth cameras or motion capture suits, an increasing amount of detailed gait data is captured and processed. The introduction and rise of the Metaverse is an example of a potentially popular application scenario in which the gait of users is transferred onto digital avatars. As a first step towards developing effective anonymization techniques for high-quality gait data, we study different aspects of movement data to quantify their contribution to gait recognition. We first extract categories of features from the literature on human gait perception and then design experiments for each category to assess how much the information they contain contributes to recognition success. We evaluated the utility of gait perturbation by means of naturalness ratings in a user study. Our results show that gait anonymization will be challenging, as the data is highly redundant and inter-dependent.

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Kozma, Elaine E., Nicole M. Webb, William E. H. Harcourt-Smith, David A. Raichlen, Kristiaan D'Août, Mary H. Brown, Emma M. Finestone, Stephen R. Ross, Peter Aerts e Herman Pontzer. "Hip extensor mechanics and the evolution of walking and climbing capabilities in humans, apes, and fossil hominins". Proceedings of the National Academy of Sciences 115, n. 16 (2 aprile 2018): 4134–39. http://dx.doi.org/10.1073/pnas.1715120115.

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The evolutionary emergence of humans’ remarkably economical walking gait remains a focus of research and debate, but experimentally validated approaches linking locomotor capability to postcranial anatomy are limited. In this study, we integrated 3D morphometrics of hominoid pelvic shape with experimental measurements of hip kinematics and kinetics during walking and climbing, hamstring activity, and passive range of hip extension in humans, apes, and other primates to assess arboreal–terrestrial trade-offs in ischium morphology among living taxa. We show that hamstring-powered hip extension during habitual walking and climbing in living apes and humans is strongly predicted, and likely constrained, by the relative length and orientation of the ischium. Ape pelves permit greater extensor moments at the hip, enhancing climbing capability, but limit their range of hip extension, resulting in a crouched gait. Human pelves reduce hip extensor moments but permit a greater degree of hip extension, which greatly improves walking economy (i.e., distance traveled/energy consumed). Applying these results to fossil pelves suggests that early hominins differed from both humans and extant apes in having an economical walking gait without sacrificing climbing capability. Ardipithecus was capable of nearly human-like hip extension during bipedal walking, but retained the capacity for powerful, ape-like hip extension during vertical climbing. Hip extension capability was essentially human-like in Australopithecus afarensis and Australopithecus africanus, suggesting an economical walking gait but reduced mechanical advantage for powered hip extension during climbing.

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Pequera, Germán, Ignacio Ramírez Paulino e Carlo M. Biancardi. "Common motor patterns of asymmetrical and symmetrical bipedal gaits". PeerJ 9 (16 agosto 2021): e11970. http://dx.doi.org/10.7717/peerj.11970.

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Background Synergy modules have been used to describe activation of lower limb muscles during locomotion and hence to understand how the system controls movement. Walking and running have been shown shared synergy patterns suggesting common motor control of both symmetrical gaits. Unilateral skipping, an equivalent gait to the quadrupedal gallop in humans, has been defined as the third locomotion paradigm but the use by humans is limited due to its high metabolic cost. Synergies in skipping have been little investigated. In particular, to the best of our knowledge, the joint study of both trailing and leading limbs has never been addressed before. Research question How are organized muscle activation patterns in unilateral skipping? Are they organized in the same way that in symmetrical gaits? If yes, which are the muscle activation patterns in skipping that make it a different gait to walking or running? In the present research, we investigate if there are shared control strategies for all gaits in locomotion. Addressing these questions in terms of muscle synergies could suggest possible determinants of the scarce use of unilateral skipping in humans. Methods Electromyographic data of fourteen bilateral muscles were collected from volunteers while performing walking, running and unilateral skipping on a treadmill. Also, spatiotemporal gait parameters were computed from 3D kinematics. The modular composition and activation timing extracted by non-negative matrix factorization were analyzed to detect similarities and differences among symmetrical gaits and unilateral skipping. Results Synergy modules showed high similarity throughout the different gaits and between trailing and leading limbs during unilateral skipping. The synergy associated with the propulsion force operated by calf muscles was anticipated in bouncing gaits. Temporal features of synergies in the leading leg were very similar to those observed for running. The different role of trailing and leading legs in unilateral skipping was reflected by the different timing in two modules. Activation for weight acceptance was anticipated and extended in the trailing leg, preparing the body for landing impact after the flight phase. A different behaviour was detected in the leading leg, which only deals with a pendular weight transference. Significance The evidence gathered in this work supports the hypothesis of shared modules among symmetrical and asymmetrical gaits, suggesting a common motor control despite of the infrequent use of unilateral skipping in humans. Unilateral skipping results from phase-shifted activation of similar muscular groups used in symmetrical gaits, without the need for new muscular groups. The high and anticipated muscle activation in the trailing leg for landing could be the key distinctive event of unilateral skipping.

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Sarangi, Viswadeep, Adar Pelah, William Edward Hahn e Elan Barenholtz. "Neural and Neuromimetic Perception: A Comparative Study of Gender Classification from Human Gait". Journal of Perceptual Imaging 3, n. 1 (1 gennaio 2020): 10402–1. http://dx.doi.org/10.2352/j.percept.imaging.2020.3.1.010402.

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Abstract Humans are adept at perceiving biological motion for purposes such as the discrimination of gender. Observers classify the gender of a walker at significantly above chance levels from a point-light distribution of joint trajectories. However, performance drops to chance level or below for vertically inverted stimuli, a phenomenon known as the inversion effect. This lack of robustness may reflect either a generic learning mechanism that has been exposed to insufficient instances of inverted stimuli or the activation of specialized mechanisms that are pre-tuned to upright stimuli. To address this issue, the authors compare the psychophysical performance of humans with the computational performance of neuromimetic machine-learning models in the classification of gender from gait by using the same biological motion stimulus set. Experimental results demonstrate significant similarities, which include those in the predominance of kinematic motion cues over structural cues in classification accuracy. Second, learning is expressed in the presence of the inversion effect in the models as in humans, suggesting that humans may use generic learning systems in the perception of biological motion in this task. Finally, modifications are applied to the model based on human perception, which mitigates the inversion effect and improves performance accuracy. The study proposes a paradigm for the investigation of human gender perception from gait and makes use of perceptual characteristics to develop a robust artificial gait classifier for potential applications such as clinical movement analysis.

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Roeder, Luisa, Tjeerd W. Boonstra, Simon S. Smith e Graham K. Kerr. "Dynamics of corticospinal motor control during overground and treadmill walking in humans". Journal of Neurophysiology 120, n. 3 (1 settembre 2018): 1017–31. http://dx.doi.org/10.1152/jn.00613.2017.

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Increasing evidence suggests cortical involvement in the control of human gait. However, the nature of corticospinal interactions remains poorly understood. We performed time-frequency analysis of electrophysiological activity acquired during treadmill and overground walking in 22 healthy, young adults. Participants walked at their preferred speed (4.2, SD 0.4 km/h), which was matched across both gait conditions. Event-related power, corticomuscular coherence (CMC), and intertrial coherence (ITC) were assessed for EEG from bilateral sensorimotor cortices and EMG from the bilateral tibialis anterior (TA) muscles. Cortical power, CMC, and ITC at theta, alpha, beta, and gamma frequencies (4–45 Hz) increased during the double support phase of the gait cycle for both overground and treadmill walking. High beta (21–30 Hz) CMC and ITC of EMG was significantly increased during overground compared with treadmill walking, as well as EEG power in theta band (4–7 Hz). The phase spectra revealed positive time lags at alpha, beta, and gamma frequencies, indicating that the EEG response preceded the EMG response. The parallel increases in power, CMC, and ITC during double support suggest evoked responses at spinal and cortical populations rather than a modulation of ongoing corticospinal oscillatory interactions. The evoked responses are not consistent with the idea of synchronization of ongoing corticospinal oscillations but instead suggest coordinated cortical and spinal inputs during the double support phase. Frequency-band dependent differences in power, CMC, and ITC between overground and treadmill walking suggest differing neural control for the two gait modalities, emphasizing the task-dependent nature of neural processes during human walking. NEW & NOTEWORTHY We investigated cortical and spinal activity during overground and treadmill walking in healthy adults. Parallel increases in power, corticomuscular coherence, and intertrial coherence during double support suggest evoked responses at spinal and cortical populations rather than a modulation of ongoing corticospinal oscillatory interactions. These findings identify neurophysiological mechanisms that are important for understanding cortical control of human gait in health and disease.

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Angadi, Sanjeevkumar, e Suvarna Nandyal. "Human Identification System Based on Spatial and Temporal Features in the Video Surveillance System". International Journal of Ambient Computing and Intelligence 11, n. 3 (luglio 2020): 1–21. http://dx.doi.org/10.4018/ijaci.2020070101.

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Human identification is the most significant topic in the bioinformatics field. Various human gait identification methods are available to identify humans, but detecting the objects based on the human gait is still a challenging task in the video surveillance system. Thus, an effective hybrid Bayesian approach is proposed for identifying the humans. The proposed hybrid Bayesian approach involves two stages as follows: the first stage is the human identification based on the object features, and the second stage is the human identification based on the spatial features. Initially, the videos are fed into the first stage, where the object detection is performed using the Viola Jones algorithm. Once the objects are detected, the feature extraction process is carried out by using a hierarchical skeleton to effectively extract the selective features. The object skeleton provides an effective and intuitive abstraction, which offers object recognition and object matching. The Bayesian network is adapted in the object-based features to identify humans. In the spatial-based human identification stage, only the spatial features are extracted and are passed into the gait-based Bayesian network to identify the humans. Finally, the resulted output is obtained using the fuzzy holoentropy for identifying the humans. The experimentation of the proposed hybrid Bayesian approach is performed using the dataset named UCF-Crime, and the performance is evaluated by considering the average value of the metrics, namely F1-score, precision, and recall which acquired 0.8820, 0.8770, and 0.9203, respectively.

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Sayeed, Md Shohel, Ibrahim Bin Yusof, Mohd Fikri Azli bin Abdullah, Md Ahsanul Bari e Pa Pa Min. "A comprehensive survey on deep-learning based gait recognition for humans in the COVID-19 pandemic". Indonesian Journal of Electrical Engineering and Computer Science 30, n. 2 (1 maggio 2023): 882. http://dx.doi.org/10.11591/ijeecs.v30.i2.pp882-902.

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Human gait recognition is a biometric technique that has been utilized for security purposes for the last decade. Gait recognition is an appealing biometric modality that aims to identify individuals based on the way they walk. The outbreak of the novel coronavirus (COVID-19), has spread across the world. The number of people infected with COVID-19 is rising rapidly throughout the world. Even though some vaccines for this pandemic have been developed to minimize the effects of COVID-19, deep learning-based gait recognition techniques have shown themselves to be an effective tool for identifying the individuals wearing face mask in COVID-19 pandemic. These techniques play an important part in reducing the rate of COVID-19 spreading throughout the world in the context of the COVID-19 pandemic. Deep learning methods are currently dominating the state-of-the-art in gait recognition and have fostered real-world applications. The main objective of this paper is to provide a comprehensive overview of recent advancements in gait recognition with deep learning, including datasets, test protocols, state-of-the-art solutions, challenges, and future research directions. The purpose of this discussion is to identify current challenges that need to be addressed as well as to suggest some directions for future research that could be explored.

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SAITO, Hideaki, Shin-Ichiro YAMAMOTO e Tasuku MIYOSHI. "611 Development of system for measuring stretch reflex in humans during gait". Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 2007.20 (2008): 225–26. http://dx.doi.org/10.1299/jsmebio.2007.20.225.

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Usherwood, J. R., K. L. Szymanek e M. A. Daley. "Compass gait mechanics account for top walking speeds in ducks and humans". Journal of Experimental Biology 211, n. 23 (1 dicembre 2008): 3744–49. http://dx.doi.org/10.1242/jeb.023416.

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Maezawa, Hitoshi, Satoko Koganemaru, Masao Matsuhashi, Masayuki Hirata, Makoto Funahashi e Tatsuya Mima. "Entrainment of chewing rhythm by gait speed during treadmill walking in humans". Neuroscience Research 156 (luglio 2020): 88–94. http://dx.doi.org/10.1016/j.neures.2020.02.008.

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Miyai, Ichiro, Hiroki C. Tanabe, Ichiro Sase, Hideo Eda, Ichiro Oda, Ikuo Konishi, Yoshio Tsunazawa, Tsunehiko Suzuki, Toshio Yanagida e Kisou Kubota. "Cortical Mapping of Gait in Humans: A Near-Infrared Spectroscopic Topography Study". NeuroImage 14, n. 5 (novembre 2001): 1186–92. http://dx.doi.org/10.1006/nimg.2001.0905.

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Bower, Bruce. "Humans & society: Meeting notes: Laetoli footprints show signs of unusual gait". Science News 185, n. 11 (22 maggio 2014): 11. http://dx.doi.org/10.1002/scin.5591851110.

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Bradford, J. Cortney, Jamie R. Lukos e Daniel P. Ferris. "Electrocortical activity distinguishes between uphill and level walking in humans". Journal of Neurophysiology 115, n. 2 (1 febbraio 2016): 958–66. http://dx.doi.org/10.1152/jn.00089.2015.

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Abstract (sommario):

The objective of this study was to determine if electrocortical activity is different between walking on an incline compared with level surface. Subjects walked on a treadmill at 0% and 15% grades for 30 min while we recorded electroencephalography (EEG). We used independent component (IC) analysis to parse EEG signals into maximally independent sources and then computed dipole estimations for each IC. We clustered cortical source ICs and analyzed event-related spectral perturbations synchronized to gait events. Theta power fluctuated across the gait cycle for both conditions, but was greater during incline walking in the anterior cingulate, sensorimotor and posterior parietal clusters. We found greater gamma power during level walking in the left sensorimotor and anterior cingulate clusters. We also found distinct alpha and beta fluctuations, depending on the phase of the gait cycle for the left and right sensorimotor cortices, indicating cortical lateralization for both walking conditions. We validated the results by isolating movement artifact. We found that the frequency activation patterns of the artifact were different than the actual EEG data, providing evidence that the differences between walking conditions were cortically driven rather than a residual artifact of the experiment. These findings suggest that the locomotor pattern adjustments necessary to walk on an incline compared with level surface may require supraspinal input, especially from the left sensorimotor cortex, anterior cingulate, and posterior parietal areas. These results are a promising step toward the use of EEG as a feed-forward control signal for ambulatory brain-computer interface technologies.

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Nerakae, Krissana, e Hiroshi Hasegawa. "Bigtoe Sizing Design of Small Biped Robot by Using Gait Generation Method". Applied Mechanics and Materials 541-542 (marzo 2014): 1079–86. http://dx.doi.org/10.4028/www.scientific.net/amm.541-542.1079.

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The study of biped robot has long history and continuation. One of important moving processes is walking procedure. The walking posture is an important research field that always adapts and implements in the biped robot. The walking research field is very interesting because the walking posture of humans is flexible and stable. Additionally, the force that affect on the humans foot is also investigated. This research addresses the walking simulation of small biped robots that have tiptoe and bigtoe. The study based on the assumption that the bigtoe size affects on the walking posture and walking distance. The gait generation method, for finding the proper size of bigtoe, is utilized by varying the bigtoe size. There are two requirements of robot design: go straight and stay within setting conditions. The simulation results of all small biped robot models which have the different bigtoe sizes can walk within setting conditions. There is only one model its bigtoe width per foot width ratio equals 0.28 (or 28% of foot width) has the longest walking distance. Moreover, this ratio is equal to the ratio of humans foot.

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Tahmoush, Dave, e Jerry Silvious. "Gait Variations in Human Micro-Doppler". International Journal of Electronics and Telecommunications 57, n. 1 (1 marzo 2011): 23–28. http://dx.doi.org/10.2478/v10177-011-0003-1.

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Gait Variations in Human Micro-DopplerMeasurement of human gait variation is important for security applications such as the indication of unexpected loading due to concealed weapons. To observe humans safely, unobtrusively, and without privacy issues, radar provides one method to detect abnormal activity without using images. In this paper we focus on modeling the characteristics of human walking parameters in order to determine signature differences that are distinguishable and to determine the variability of normal walking to be compared to armed or loaded walking. We extract micro-Doppler from motion-captured human gait models and verify the models with radar measurements. We then vary the model to determine the extent of normal micro-Doppler variation in multiple dimensions of human gait. We also characterize the ability of radar to determine gender and suggest that alternative views to the frontal view may be more discriminative.

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Rahman, Mizanur, Jennifer E. Hewitt, Frank Van-Bussel, Hunter Edwards, Jerzy Blawzdziewicz, Nathaniel J. Szewczyk, Monica Driscoll e Siva A. Vanapalli. "NemaFlex: a microfluidics-based technology for standardized measurement of muscular strength of C. elegans". Lab on a Chip 18, n. 15 (2018): 2187–201. http://dx.doi.org/10.1039/c8lc00103k.

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Matthis, Jonathan Samir, e Brett R. Fajen. "Humans exploit the biomechanics of bipedal gait during visually guided walking over complex terrain". Proceedings of the Royal Society B: Biological Sciences 280, n. 1762 (7 luglio 2013): 20130700. http://dx.doi.org/10.1098/rspb.2013.0700.

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How do humans achieve such remarkable energetic efficiency when walking over complex terrain such as a rocky trail? Recent research in biomechanics suggests that the efficiency of human walking over flat, obstacle-free terrain derives from the ability to exploit the physical dynamics of our bodies. In this study, we investigated whether this principle also applies to visually guided walking over complex terrain. We found that when humans can see the immediate foreground as little as two step lengths ahead, they are able to choose footholds that allow them to exploit their biomechanical structure as efficiently as they can with unlimited visual information. We conclude that when humans walk over complex terrain, they use visual information from two step lengths ahead to choose footholds that allow them to approximate the energetic efficiency of walking in flat, obstacle-free environments.

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Sun, Lei, Hongxu Ma, Honglei An e Qing Wei. "An Individual Prosthesis Control Method with Human Subjective Choices". Biomimetics 9, n. 2 (27 gennaio 2024): 77. http://dx.doi.org/10.3390/biomimetics9020077.

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An intelligent lower-limb prosthesis can provide walking support and convenience for lower-limb amputees. Trajectory planning of prosthesis joints plays an important role in the intelligent prosthetic control system, which directly determines the performance and helps improve comfort when wearing the prosthesis. Due to the differences in physiology and walking habits, humans have their own walking mode that requires the prosthesis to consider the individual’s demands when planning the prosthesis joint trajectories. The human is an integral part of the control loop, whose subjective feeling is important feedback information, as humans can evaluate many indicators that are difficult to quantify and model. In this study, trajectories were built using the phase variable method by normalizing the gait curve to a unified range. The deviations between the optimal trajectory and current were represented using Fourier series expansion. A gait dataset that contains multi-subject kinematics data is used in the experiments to prove the feasibility and effectiveness of this method. In the experiments, we optimized the subjects’ gait trajectories from an average to an individual gait trajectory. By using the individual trajectory planning algorithm, the average gait trajectory can be effectively optimized into a personalized trajectory, which is beneficial for improving walking comfort and safety and bringing the prosthesis closer to intelligence.

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Hasson, Christopher J., e Sarah E. Goodman. "Learning to shape virtual patient locomotor patterns: internal representations adapt to exploit interactive dynamics". Journal of Neurophysiology 121, n. 1 (1 gennaio 2019): 321–35. http://dx.doi.org/10.1152/jn.00408.2018.

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This work aimed to understand the sensorimotor processes used by humans when learning how to manipulate a virtual model of locomotor dynamics. Prior research shows that when interacting with novel dynamics humans develop internal models that map neural commands to limb motion and vice versa. Whether this can be extrapolated to locomotor rehabilitation, a continuous and rhythmic activity that involves dynamically complex interactions, is unknown. In this case, humans could default to model-free strategies. These competing hypotheses were tested with a novel interactive locomotor simulator that reproduced the dynamics of hemiparetic gait. A group of 16 healthy subjects practiced using a small robotic manipulandum to alter the gait of a virtual patient (VP) that had an asymmetric locomotor pattern modeled after stroke survivors. The point of interaction was the ankle of the VP’s affected leg, and the goal was to make the VP’s gait symmetric. Internal model formation was probed with unexpected force channels and null force fields. Generalization was assessed by changing the target locomotor pattern and comparing outcomes with a second group of 10 naive subjects who did not practice the initial symmetric target pattern. Results supported the internal model hypothesis with aftereffects and generalization of manipulation skill. Internal models demonstrated refinements that capitalized on the natural pendular dynamics of human locomotion. This work shows that despite the complex interactive dynamics involved in shaping locomotor patterns, humans nevertheless develop and use internal models that are refined with experience.NEW & NOTEWORTHY This study aimed to understand how humans manipulate the physics of locomotion, a common task for physical therapists during locomotor rehabilitation. To achieve this aim, a novel locomotor simulator was developed that allowed participants to feel like they were manipulating the leg of a miniature virtual stroke survivor walking on a treadmill. As participants practiced improving the simulated patient’s gait, they developed generalizable internal models that capitalized on the natural pendular dynamics of locomotion.

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Larsson, Matz, Joachim Richter e Andrea Ravignani. "Bipedal Steps in the Development of Rhythmic Behavior in Humans". Music & Science 2 (1 gennaio 2019): 205920431989261. http://dx.doi.org/10.1177/2059204319892617.

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We contrast two related hypotheses of the evolution of dance: H1: Maternal bipedal walking influenced the fetal experience of sound and associated movement patterns; H2: The human transition to bipedal gait produced more isochronous/predictable locomotion sound resulting in early music-like behavior associated with the acoustic advantages conferred by moving bipedally in pace. The cadence of walking is around 120 beats per minute, similar to the tempo of dance and music. Human walking displays long-term constancies. Dyads often subconsciously synchronize steps. The major amplitude component of the step is a distinctly produced beat. Human locomotion influences, and interacts with, emotions, and passive listening to music activates brain motor areas. Across dance-genres the footwork is most often performed in time to the musical beat. Brain development is largely shaped by early sensory experience, with hearing developed from week 18 of gestation. Newborns reacts to sounds, melodies, and rhythmic poems to which they have been exposed in utero. If the sound and vibrations produced by footfalls of a walking mother are transmitted to the fetus in coordination with the cadence of the motion, a connection between isochronous sound and rhythmical movement may be developed. Rhythmical sounds of the human mother locomotion differ substantially from that of nonhuman primates, while the maternal heartbeat heard is likely to have a similar isochronous character across primates, suggesting a relatively more influential role of footfall in the development of rhythmic/musical abilities in humans. Associations of gait, music, and dance are numerous. The apparent absence of musical and rhythmic abilities in nonhuman primates, which display little bipedal locomotion, corroborates that bipedal gait may be linked to the development of rhythmic abilities in humans. Bipedal stimuli in utero may primarily boost the ontogenetic development. The acoustical advantage hypothesis proposes a mechanism in the phylogenetic development.

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Ivanenko, Yuri P., Francesca Sylos Labini, Germana Cappellini, Velio Macellari, Joseph McIntyre e Francesco Lacquaniti. "Gait transitions in simulated reduced gravity". Journal of Applied Physiology 110, n. 3 (marzo 2011): 781–88. http://dx.doi.org/10.1152/japplphysiol.00799.2010.

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Abstract (sommario):

Gravity has a strong effect on gait and the speed of gait transitions. A gait has been defined as a pattern of locomotion that changes discontinuously at the transition to another gait. On Earth, during gradual speed changes, humans exhibit a sudden discontinuous switch from walking to running at a specific speed. To study the effects of altered gravity on both the stance and swing legs, we developed a novel unloading exoskeleton that allows a person to step in simulated reduced gravity by tilting the body relative to the vertical. Using different simulation techniques, we confirmed that at lower gravity levels the transition speed is slower (in accordance with the previously reported Froude number ∼0.5). Surprisingly, however, we found that at lower levels of simulated gravity the transition between walking and running was generally gradual, without any noticeable abrupt change in gait parameters. This was associated with a significant prolongation of the swing phase, whose duration became virtually equal to that of stance in the vicinity of the walk-run transition speed, and with a gradual shift from inverted-pendulum gait (walking) to bouncing gait (running).

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