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1.
Sci Rep ; 14(1): 8012, 2024 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-38580704

RESUMO

The objective of human pose estimation (HPE) derived from deep learning aims to accurately estimate and predict the human body posture in images or videos via the utilization of deep neural networks. However, the accuracy of real-time HPE tasks is still to be improved due to factors such as partial occlusion of body parts and limited receptive field of the model. To alleviate the accuracy loss caused by these issues, this paper proposes a real-time HPE model called CCAM - Person based on the YOLOv8 framework. Specifically, we have improved the backbone and neck of the YOLOv8x-pose real-time HPE model to alleviate the feature loss and receptive field constraints. Secondly, we introduce the context coordinate attention module (CCAM) to augment the model's focus on salient features, reduce background noise interference, alleviate key point regression failure caused by limb occlusion, and improve the accuracy of pose estimation. Our approach attains competitive results on multiple metrics of two open-source datasets, MS COCO 2017 and CrowdPose. Compared with the baseline model YOLOv8x-pose, CCAM-Person improves the average precision by 2.8% and 3.5% on the two datasets, respectively.


Assuntos
Benchmarking , Extremidades , Humanos , Redes Neurais de Computação , Postura , Gravação de Videoteipe
2.
PeerJ ; 12: e17173, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38560460

RESUMO

Background: Table tennis is an asymmetric sport involving the powerful forward swing of the upper limbs depends on the solid support of the lower limbs. The foot drive really affects the weight balance and stroke accuracy even though the distance and momentum of the lower limb displacement are limited within a limited range. Given that previous research on table tennis has typically focused on the footwork and stroke performance of professional players, the study aimed to investigate the daily static and dynamic plantar load distribution as well as the centers of gravity balance and rearfoot posture among Taiwanese college elite table tennis players. Methods: This is a cross-sectional study of 70 elite male table tennis players (age: 20.0 ± 0.9 years; height: 173.4 ± 5.1 cm, weight: 67.6 ± 5.3 kg, experience: 10.0 ± 1.6 years) and 77 amateur table tennis players of the same gender (age: 20.1 ± 0.8 years, height: 167.4 ± 4.4 cm, weight: 64.3 ± 4.0 kg, experience: 4.4 ± 1.2 years) from Taiwanese universities. The JC Mat optical plantar pressure analyzer was applied to determine the plantar load distribution along with arch index (AI) and centers of gravity balance. Assessment of rearfoot postural alignment was mainly used to contrast the performance of the centers of gravity balance. Results: The static arch indices of both feet in the elite group were symmetrical and considered normal arches (AI: 0.22 ± 0.07) during their non-training and non-competition daily lives. Their static plantar loads were symmetrically concentrated on the bipedal lateral metatarsals (P < 0.05) as well as shifted to the medial and lateral heels (P < 0.05) and the lateral metatarsals (P < 0.05) during the walking midstance phase. Additionally, the plantar loads were mainly applied to the bipedal medial (P < 0.01) and lateral heels (P < 0.05) during the transitional changes between both states. Elite athletes had symmetrical and evenly distributed centers of gravity on both feet (left: 50.03 ± 4.47%; right: 49.97 ± 4.47%) when standing statically, along with symmetrical rearfoot angles and neutral position of the subtalar joint (left: 2.73 ± 2.30°; right: 2.70 ± 2.32°) even though they were statistically lower than those of the amateur athletes (P < 0.05). Conclusions: The daily static and dynamic foot patterns of Taiwanese college elite table tennis players were characterized by plantar load distribution on the lateral metatarsals and the entire calcaneus along with balanced centers of gravity and normal rearfoot posture. This foot and posture layout outlines the excellent athletic performance of the foot and ankle in professional athletes. Portions of this text were previously published as part of a preprint (https://doi.org/10.21203/rs.3.rs-2993403/v1).


Assuntos
Acidente Vascular Cerebral , Tênis , Humanos , Masculino , Adulto Jovem , Adulto , Estudos Transversais , Universidades , Postura
3.
Sci Rep ; 14(1): 8251, 2024 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-38589504

RESUMO

Investigating acute stress responses is crucial to understanding the underlying mechanisms of stress. Current stress assessment methods include self-reports that can be biased and biomarkers that are often based on complex laboratory procedures. A promising additional modality for stress assessment might be the observation of body movements, which are affected by negative emotions and threatening situations. In this paper, we investigated the relationship between acute psychosocial stress induction and body posture and movements. We collected motion data from N = 59 individuals over two studies (Pilot Study: N = 20, Main Study: N = 39) using inertial measurement unit (IMU)-based motion capture suits. In both studies, individuals underwent the Trier Social Stress Test (TSST) and a stress-free control condition (friendly-TSST; f-TSST) in randomized order. Our results show that acute stress induction leads to a reproducible freezing behavior, characterized by less overall motion as well as more and longer periods of no movement. Based on these data, we trained machine learning pipelines to detect acute stress solely from movement information, achieving an accuracy of 75.0 ± 17.7 % (Pilot Study) and 73.4 ± 7.7 % (Main Study). This, for the first time, suggests that body posture and movements can be used to detect whether individuals are exposed to acute psychosocial stress. While more studies are needed to further validate our approach, we are convinced that motion information can be a valuable extension to the existing biomarkers and can help to obtain a more holistic picture of the human stress response. Our work is the first to systematically explore the use of full-body body posture and movement to gain novel insights into the human stress response and its effects on the body and mind.


Assuntos
Hidrocortisona , Estresse Psicológico , Humanos , Estresse Psicológico/psicologia , Projetos Piloto , Postura , Biomarcadores , Saliva
4.
Arq Bras Cardiol ; 121(2): e20230483, 2024.
Artigo em Português, Inglês | MEDLINE | ID: mdl-38597534

RESUMO

BACKGROUND: Duchenne Muscular Dystrophy (DMD) is a rare inherited neuromuscular disease. At first, cardiac involvement may be asymptomatic. Therefore, assessing patients using non-invasive methods can help detect any changes. OBJECTIVES: Analyze the electrocardiogram (ECG) test and heart rate variability (HRV) of the DMD group and compare the information with that of the age-matched control group. METHODS: A prospective study with 27 male patients with DMD (11.9 years old), who underwent clinical evaluation, ECG, echocardiogram, and Holter monitoring. ECG (200% increase) was assessed by two independent observers. HRV was measured over time (24 h) and in the frequency domain, in the supine and sitting positions. The healthy group consisted of nine patients (11.0 years old). A value of p < 0.05 was considered statistically significant. RESULTS: The mean ejection fraction (EF) was 60% (34 to 71%). The Kappa coefficient for ECG measurements ranged from 0.64 to 1.00. An increase in the R/S ratio in V1 was observed in 25.9% of the subjects, pathological Q wave in 29.6%, and fragmented QRS in 22.2% in inferior/high lateral regions, with a negative correlation with EF (p = 0.006). There was low HRV, without the influence of any variable, including treatment. With the change in position, there was an increase in HR (p = 0.004), but there was no change in HRV. The LF/HF ratio was 2.7 in the DMD group and 0.7 in the control group (p = 0.002). CONCLUSIONS: In DMD subjects, prominent R waves in V1 and changes in the inferior/high lateral regions occurred in almost 30% of the cases. Lower vagal tone was observed without the influence of the variables age, ejection fraction, QT dispersion, and treatment. Despite the increase in HR, there was no adequate HRV response to the change in position.


FUNDAMENTO: Distrofia Muscular de Duchenne (DMD) é uma doença neuromuscular hereditária rara. O acometimento cardíaco inicial pode ser assintomático. Portanto, a avaliação por métodos não invasivos pode auxiliar sua abordagem. OBJETIVOS: Analisar o eletrocardiograma (ECG) e a variabilidade da frequência cardíaca (VFC) do grupo com DMD, e comparar com a do grupo controle pareado por idade. MÉTODOS: Estudo prospectivo com 27 pacientes masculinos com DMD (idade de 11,9 anos) que foram submetidos à avaliação clínica, ECG, ecocardiograma e Holter. ECG (aumento de 200%) foi avaliado por dois observadores independentes. VFC foi feita no domínio do tempo (24 h) e da frequência na posição supina e sentada. O grupo saudável foi de nove pacientes (11,0 anos). Um valor de p < 0,05 foi considerado estatisticamente significante. RESULTADOS: A média da fração de ejeção (FE) foi de 60% (34 a 71%). O coeficiente de Kappa para as medidas do ECG variou de 0,64 a 1,00. Foram verificados aumento da relação R/S em V1 em 25,9%, onda Q patológica em 29,6% e QRS fragmentado em 22,2% em regiões inferior/lateral alta, este com correlação negativa com FE (p = 0,006). Houve baixa VFC, sem influência de nenhuma variável, inclusive tratamento. Com a mudança da posição, houve aumento da FC (p = 0,004), porém não houve alteração da VFC. A relação LF/HF foi de 2,7 na DMD e de 0,7 no controle (p = 0,002). CONCLUSÕES: Nos participantes com DMD, as ondas R proeminentes em V1 e alterações nas regiões inferior/lateral alta ocorreram em quase 30% dos casos. Houve menor tônus vagal sem influência das variáveis idade, fração de ejeção, dispersão do QT e tratamento. Apesar do aumento da FC, não houve resposta adequada da VFC com a mudança de posição.


Assuntos
Distrofia Muscular de Duchenne , Criança , Humanos , Masculino , Adolescente , Estudos Prospectivos , Eletrocardiografia , Sistema Nervoso Autônomo , Frequência Cardíaca/fisiologia , Postura
5.
BMC Pregnancy Childbirth ; 24(1): 253, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38589802

RESUMO

BACKGROUND: The objective of this study was to identify and qualify, by means of a three-dimensional kinematic analysis, the postures and movements of obstetricians during a simulated forceps birth, and then to study the association of the obstetricians' experience with the technique adopted. METHOD: Fifty-seven volunteer obstetricians, 20 from the Limoges and 37 from the Poitiers University hospitals, were included in this multi-centric study. They were classified into 3 groups: beginners, intermediates, and experts, beginners having performed fewer than 10 forceps deliveries in real conditions, intermediates between 10 and 100, and experts more than 100. The posture and movements of the obstetricians were recorded between December 2020 and March 2021 using an optoelectronic motion capture system during simulated forceps births. Joint angles qualifying these postures and movements were analysed between the three phases of the foetal traction. These phases were defined by the passage of a virtual point associated with the forceps blade through two anatomical planes: the mid-pelvis and the pelvic outlet. Then, a consolidated ascending hierarchical classification (AHC) was applied to these data in order to objectify the existence of groups of similar behaviours. RESULTS: The AHC distinguished four different postures adopted when crossing the first plane and three different traction techniques. 48% of the beginners adopted one of the two raised posture, 22% being raised without trunk flexion and 26% raised with trunk flexion. Conversely, 58% of the experts positioned themselves in a "chevalier servant" posture (going down on one knee) and 25% in a "squatting" posture before initiating traction. The results also show that the joint movement amplitude tends to reduce with the level of expertise. CONCLUSION: Forceps delivery was performed in different ways, with the experienced obstetricians favouring postures that enabled observation at the level of the maternal perineum and techniques reducing movement amplitude. The first perspective of this work is to relate these different techniques to the traction force generated. The results of these studies have the potential to contribute to the training of obstetricians in forceps delivery, and to improve the safety of women and newborns.


Assuntos
Extração Obstétrica , Obstetra , Gravidez , Humanos , Feminino , Recém-Nascido , Extração Obstétrica/métodos , Parto Obstétrico , Forceps Obstétrico , Postura
6.
Sci Rep ; 14(1): 8341, 2024 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-38594312

RESUMO

The motor neuroscience literature suggests that the central nervous system may encode some motor commands in terms of velocity. In this work, we tackle the question: what consequences would velocity commands produce at the behavioral level? Considering the ubiquitous presence of noise in the neuromusculoskeletal system, we predict that velocity commands affected by stationary noise would produce "random walks", also known as Brownian processes, in position. Brownian motions are distinctively characterized by a linearly growing variance and a power spectral density that declines in inverse proportion to frequency. This work first shows that these Brownian processes are indeed observed in unbounded motion tasks e.g., rotating a crank. We further predict that such growing variance would still be present, but bounded, in tasks requiring a constant posture e.g., maintaining a static hand position or quietly standing. This hypothesis was also confirmed by experimental observations. A series of descriptive models are investigated to justify the observed behavior. Interestingly, one of the models capable of accounting for all the experimental results must feature forward-path velocity commands corrupted by stationary noise. The results of this work provide behavioral support for the hypothesis that humans plan the motion components of their actions in terms of velocity.


Assuntos
Mãos , Postura , Humanos , Movimento (Física)
7.
J Robot Surg ; 18(1): 112, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38441746

RESUMO

The conventional supine position for robotic thymectomy may present challenges in accessing the lower thymic horns, particularly in cases requiring extensive resection of mediastinal fat. To address this issue, the authors advocate for a lateral patient position during the procedure, emphasizing optimized access to the thymic horns and improved procedural efficacy. The lateral approach involves specific trocar placements and port arrangements to minimize conflicts between instruments. This report proposes an innovative approach to robotic thymectomy for patients diagnosed with thymoma or thymic hyperplasia associated with myasthenia gravis.


Assuntos
Procedimentos Cirúrgicos Robóticos , Neoplasias do Timo , Animais , Humanos , Timectomia , Procedimentos Cirúrgicos Robóticos/métodos , Timo , Postura , Neoplasias do Timo/cirurgia
8.
PLoS One ; 19(3): e0297863, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38446782

RESUMO

Forward Head Posture (FHP) is one of the most commonly occurring musculoskeletal abnormalities. Despite exercise therapy being an effective approach for FHP treatment, it can be long, monotonous, and tedious. Virtual reality (VR) can be used as an innovative solution to address these challenges. We designed an affordable and immersive VR-based exercise therapy (VRET) system for FHP correction. The VRET contents (i.e., exercises and VR scenarios) were determined by physiotherapists and game designers at the focus group meetings. Hardware requirements include a VR box, smartphone, and sensors (i.e., a smartphone accelerometer and an affordable Inertial Measurement Unit (IMU)) to measure head motions and transfer them via Wi-Fi to the VRET system. The IMU was designed using the MPU6050, Arduino Nano, and ESP8266-01S. Gwet's AC1, Game Experience Questionnaires (GEQ), and System Usability Scale (SUS) were used to measure intra-rater reliability, user experience, and system usability, respectively. The determined exercises, including Capital Flexion-Extension and Chin Tuck, were designed in the form of a shooting game. A physiotherapist and twenty-one FHP individuals took part in evaluating the system. High precision was obtained for the designed IMU (i.e., pitch and roll < 0.1° and yaw < 1.3 °). Gwet's AC1 and SUS results showed very good intra-rater reliability (coefficient = 0.892) and excellent usability (score = 87.14), respectively. According to the mean scores of the GEQ, participants were confident about competence, immersion, flow, and positive affect components. The development of low-cost VRET systems for FHP correction is a step towards facilitating rehabilitation challenges by providing positive experiences for users as well as helping them perform therapeutic exercises correctly.


Assuntos
Exercício Físico , Jogos Eletrônicos de Movimento , Humanos , Reprodutibilidade dos Testes , Terapia por Exercício , Postura
9.
J Vis ; 24(3): 2, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38436983

RESUMO

Humans can accurately estimate and track object motion, even if it accelerates. Research shows that humans exhibit superior estimation and tracking performance for descending (falling) than ascending (rising) objects. Previous studies presented ascending and descending targets along the gravitational and body axes in an upright posture. Thus, it is unclear whether humans rely on congruent information between the direction of the target motion and gravity or the direction of the target motion and longitudinal body axes. Two experiments were conducted to explore these possibilities. In Experiment 1, participants estimated the arrival time at a goal for both upward and downward motion of targets along the longitudinal body axis in the upright (both axes of target motion and gravity congruent) and supine (both axes incongruent) postures. In Experiment 2, smooth pursuit eye movements were assessed while tracking both targets in the same postures. Arrival time estimation and smooth pursuit eye movement performance were consistently more accurate for downward target motion than for upward motion, irrespective of posture. These findings suggest that the visual experience of seeing an object moving along an observer's leg side in everyday life may influence the ability to accurately estimate and track the descending object's motion.


Assuntos
Gravitação , Postura , Humanos , Movimento (Física) , Acompanhamento Ocular Uniforme
10.
Sci Rep ; 14(1): 5280, 2024 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-38438541

RESUMO

The association between craniocervical posture and craniofacial structures in the various sagittal skeletal malocclusion during different growth stages has been the focus of intense interest in fields of orthodontics, but it has not been conclusively demonstrated. Thus, this study aimed to investigate the association between craniofacial morphology and craniocervical posture in patients with sagittal skeletal malocclusion during different growth periods. A total of 150 from a large pool of cephalograms qualified for the inclusion and exclusion were evaluated and classified into three groups according to the Cervical Vertebral Maturation (CVM) by examining the morphological modifications of the second through fourth cervical vertebrae, each group consisted of 50 cephalograms. In each growth period, for the comparison of head and cervical posture differences among various skeletal classes, the radiographs were further subdivided into skeletal Class I (0° < ANB < 5°, n = 16), skeletal Class II (ANB ≥ 5°, n = 18), and skeletal Class III (0° ≤ ANB, n = 16) on the basis of their ANB angle. There was no significant difference in gender (P > 0.05). Some variables were found to be significant during pubertal growth and later in patients with sagittal skeletal malocclusion (P < 0.05). Most indicators describing craniocervical posture were largest in skeletal Class II and smallest in skeletal Class III during the peak growth periods and later. Cervical inclination variables were greater in skeletal Class III than in skeletal Class II. Variables of craniofacial morphology and craniocervical posture are more correlated during the pubertal growth period and later in patients with sagittal skeletal malocclusion. A tendency is an indication of the close interrelationship that a more extended head was in skeletal Class II while a flexed head was in skeletal Class III. Nevertheless, with the considerations of some limitations involved in this study, further longitudinal studies with large samples are required to elucidate the relationship clearly.


Assuntos
Má Oclusão , Humanos , Má Oclusão/diagnóstico por imagem , Morfogênese , Pacientes , Vértebras Cervicais/diagnóstico por imagem , Postura
11.
Artigo em Inglês | MEDLINE | ID: mdl-38441974

RESUMO

BACKGROUND: Forward head posture (FHP) decreases the neck position sense and creates tension in the neck muscles, which inversely affects the mechanics of the distal joints through body myofascia. Thus, this study investigated the effects of FHP on neck and ankle joint position sense, and conducted a comparison between the joint position sense of the right and left ankle. METHODS: Fifty-seven subjects were assigned according to the craniovertebral angle (CVA) into the FHP group (CVA <49°; n = 27) or the control group (CVA >49°; n = 30). Head and ankle joint repositioning accuracy was measured by using a cervical range-of-motion device and an isokinetic dynamometer, respectively. RESULTS: There was a significant increase in the joint position error (JPE) of the cervical flexion, extension, and right and left side bending motions of the FHP group compared to the control group (P < .05). There were significant increases in the JPE of the right and left ankle dorsiflexion and plantarflexion of the FHP group compared to the healthy group (P < .05). Moreover, the JPE of the right ankle dorsiflexion and plantarflexion of the FHP group were significantly higher than the left ankle (P < .05). CONCLUSIONS: The FHP decreases the position sense of cervical flexion, extension, and right and left side bending motions, and the plantarflexion and dorsiflexion of both ankle joints, especially the right ankle joint.


Assuntos
Articulação do Tornozelo , Tornozelo , Humanos , Estudos Transversais , Propriocepção , Postura
12.
Clin Biomech (Bristol, Avon) ; 113: 106211, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38430783

RESUMO

BACKGROUND: Individuals with chronic ankle instability often present with clinical and biomechanical abnormalities, however squat biomechanics have not been investigated. The purpose of this study was to compare select clinical assessments and squat biomechanics between individuals with and without chronic ankle instability. METHODS: Fifteen individuals with chronic ankle instability and a matched control group were studied. A weight-bearing dorsiflexion lunge test, foot posture, and an in-line half-kneeling motor control test for core stability were assessed. Lower limb 3D bilateral and unilateral squat biomechanics were captured. Groups, limbs and squat tasks were compared using an alpha of 0.05. FINDINGS: Individuals with chronic ankle instability had less static weight-bearing dorsiflexion and failed the core stability test more frequently, but did not differ in foot morphology compared to the controls. When squatting, those with chronic ankle instability demonstrated reduced peak ankle dorsiflexion angles and moments in the involved limb (p < 0.04) during single limb squats and had interlimb differences in ankle dorsiflexion angle as well as hip and knee kinetics (p < 0.04) during double limb squats. In those with chronic ankle instability, there was less overall motion, but higher kinetic demands in single limb versus double leg squatting (p < 0.03). INTERPRETATION: Individuals with chronic ankle instability had impaired weight-bearing dorsiflexion and showed impaired core stability more often, which accompanied altered squatting mechanics in both variations. Within the limbs with chronic ankle instability, single limb squats showed lesser kinematic demands but higher kinetic demands than double limb squatting.


Assuntos
Tornozelo , Instabilidade Articular , Humanos , Fenômenos Biomecânicos , Articulação do Tornozelo , Amplitude de Movimento Articular , Postura , Extremidade Inferior , Articulação do Joelho
13.
Clin Biomech (Bristol, Avon) ; 113: 106220, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38458002

RESUMO

BACKGROUND: The use of movement screens as a clinical tool for injury risk assessment requires variables to be extracted across specific phases of interest. While manually selecting task events is the traditional method, automated event detection is an effective technique that maintains consistency across a cohort. This study aimed to examine variations in event identification, comparing manual detection and the application of an automated algorithm, with a specific focus on a drop vertical jump task. METHODS: Thirty participants cleared to return-to-play after anterior cruciate ligament reconstruction and thirty controls were tested. For the automated event detection, normalized vertical ground reaction force and the velocity of the sacrum marker were used to identify five events during the drop vertical jump: initial contact, end of loading, end of propulsion, second contact, and end of second loading. Two raters manually selected events and were compared to the event times of the automated algorithm. FINDINGS: Manual event detection exhibited excellent reliability Significant differences between manual and automated detection were observed, particularly at events indicating the lowest squat position (Event2 and Event5). Participants who had undergone anterior cruciate ligament reconstruction demonstrated larger differences than controls at Event5, correlating with significant squat depth disparities. INTERPRETATION: While manual event detection demonstrated reliability, automated algorithms revealed differences, specifically in events of the drop vertical jump involving the lowest squat position. The automated algorithm presents potential benefits in reducing processing time and enhancing accuracy for event identification, offering valuable insights for motion capture applications in clinical settings.


Assuntos
Lesões do Ligamento Cruzado Anterior , Humanos , Lesões do Ligamento Cruzado Anterior/cirurgia , Reprodutibilidade dos Testes , Captura de Movimento , Movimento , Postura , Fenômenos Biomecânicos , Articulação do Joelho
14.
15.
Traffic Inj Prev ; 25(3): 454-462, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38478461

RESUMO

OBJECTIVE: In vehicle frontal collisions, it is crucial that the lap belt is designed to engage with the anterior superior iliac spine (ASIS) of occupants for a reliable restraint. This study aims to understand the influence of different seated postures on the geometrical relationship of the seat belt and the pelvis for various occupants using 3D upright and supine computed tomography (CT) systems. METHODS: The 3D shapes of bones and soft tissues around the pelvis were acquired through a CT scan for 30 participants. They were seated in a rigid seat equipped with a lap belt simulating the front seat of a small car, and wore a lap belt in three seated postures: upright, slouched and reclined. Parameters related to the likelihood of submarining occurrences, such as belt-ASIS overlap (an index for assessing the potential engagement of the lap belt with the ASIS) and the belt-pelvis angle (the difference between the belt angle and the normal direction of the anterior edge of the ilium) were compared. RESULTS: It was observed that the pelvis angle tilted rearward as the hip point was positioned forward and seatback angle increased. This can be seen in the slouched and reclined posture. The belt-pelvis angle was comparable between the slouched and the reclined postures, and was closer to zero (indicating that the lap belt path is closer to perpendicular to the anterior edge of the ilium) compared to the upright posture. In contrast, the belt-ASIS overlap increased with an increasing flesh margin of the ASIS and shallower belt angle. This suggests that the belt-pelvis angle is influenced by the seated posture whereas the belt-ASIS overlap is dependent more on an individual's anthropometry. The plot of belt-pelvis angle and belt-ASIS overlap exhibited significant variability among participants. CONCLUSIONS: The belt-pelvis angle and the belt-ASIS overlap of individuals will provide valuable information for understanding the current belt-fit location and predicting submarining occurrences for individuals in various postures when designing restraint systems.


Assuntos
Acidentes de Trânsito , Cintos de Segurança , Humanos , Antropometria/métodos , Postura , Fenômenos Biomecânicos , Tomografia
16.
Artigo em Inglês | MEDLINE | ID: mdl-38498740

RESUMO

Balanced posture without dizziness is achieved via harmonious coordination of visual, vestibular, and somatosensory systems. Specific frequency bands of center of pressure (COP) signals during quiet standing are closely related to the sensory inputs of the sensorimotor system. In this study, we proposed a deep learning-based novel protocol using the COP signal frequencies to estimate the equilibrium score (ES), a sensory system contribution. Sensory organization test was performed with normal controls (n=125), patients with Meniere's disease (n=72) and vestibular neuritis (n=105). The COP signals preprocessed via filtering, detrending and augmenting during quiet standing were converted to frequency domains utilizing Short-time Fourier Transform. Four different types of CNN backbone including GoogleNet, ResNet-18, SqueezeNet, and VGG16 were trained and tested using the frequency transformed data of COP and the ES under conditions #2 to #6. Additionally, the 100 original output classes (1 to 100 ESs) were encoded into 50, 20, 10 and 5 sub-classes to improve the performance of the prediction model. Absolute difference between the measured and predicted ES was about 1.7 (ResNet-18 with encoding of 20 sub-classes). The average error of each sensory analysis calculated using the measured ES and predicted ES was approximately 1.0%. The results suggest that the sensory system contribution of patients with dizziness can be quantitatively assessed using only the COP signal from a single test of standing posture. This study has potential to reduce balance testing time (spent on six conditions with three trials each in sensory organization test) and the size of computerized dynamic posturography (movable visual surround and force plate), and helps achieve the widespread application of the balance assessment.


Assuntos
Aprendizado Profundo , Tontura , Humanos , Equilíbrio Postural , Postura , Posição Ortostática
17.
Sci Rep ; 14(1): 6427, 2024 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-38499618

RESUMO

Four-degree-of-freedom (4-DOF) human-chair coupling models are constructed to characterize the different contact modes between the head, chest back, waist back and backrest. The seat-to-head transfer ratio (STHT) is used as an evaluation metric for vibration reduction effectiveness. The simulated vibration reduction ratio of the model is close to the experimental results, which proves the validity of the model. The peak STHT is obviously reduced (P < 0.05, T-test) with seat-backrest support. The experiments show that supporting the head ( a 1 , P < 0.05, Wilcoxon matched-pairs signed ranks) has the best vibration reduction effect (21%), supporting the chest back ( a 2 , P < 0.05) has a reduced effect (11%), and supporting the waist back ( a 3 , P < 0.05) has the weakest effect (4%). When the upper torso is in full contact with the backrest, the peak STHT curve and resonance frequency are positively correlated with the contact stiffness of the seat surface and negatively correlated with the contact damping. In order to reduce the seat-to-head transfer ratio, the lowest STHT peak and lowest total energy judgments were proposed as the selection methods for the selection of the contact stiffness and damping of the backrest in two environments (periodic and non-periodic excitation), respectively.


Assuntos
Postura Sentada , Vibração , Humanos , Corpo Humano , Dorso/fisiologia , Postura/fisiologia , Fenômenos Biomecânicos
18.
Sci Rep ; 14(1): 6602, 2024 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-38503793

RESUMO

Beauty is related to our lives in various ways and examining it from an interdisciplinary approach is essential. People are very concerned with their appearance. A widely accepted beauty ideal is that the thinner an individual is, the more beautiful they are. However, the effect of continuous motion on body form aesthetics is unclear. Additionally, an upright pelvic posture in the sagittal plane during walking seems to affect the aesthetic judgments of female appearance. We directly analyzed the influence of body form and walking pattern on aesthetic visual impressions from a third-person perspective with a two-way analysis of variance. Captured motion data for three conditions-upright pelvis, normal pelvis, and posteriorly tilted pelvic posture-were applied to each of three mannequins, representing thin, standard, and obese body forms. When participants watched stimulus videos of the mannequins walking with various postures, a significantly higher score for aesthetic visual impression was noted for an upright pelvic posture than for a posteriorly tilted pelvic posture, irrespective of body form (F(2, 119) = 79.89, p < 0.001, η2 = 0.54). These findings show that the third-person perspective of beauty can be improved even without being thin by walking with an upright pelvic posture.


Assuntos
Marcha , Caminhada , Humanos , Feminino , Pelve , Postura , Estética , Fenômenos Biomecânicos
19.
Proc Natl Acad Sci U S A ; 121(12): e2308922121, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38442141

RESUMO

Fossils encompassing multiple individuals provide rare direct evidence of behavioral interactions among extinct organisms. However, the fossilization process can alter the spatial relationship between individuals and hinder behavioral reconstruction. Here, we report a Baltic amber inclusion preserving a female-male pair of the extinct termite species Electrotermes affinis. The head-to-abdomen contact in the fossilized pair resembles the tandem courtship behavior of extant termites, although their parallel body alignment differs from the linear alignment typical of tandem runs. To solve this inconsistency, we simulated the first stage of amber formation, the immobilization of captured organisms, by exposing living termite tandems to sticky surfaces. We found that the posture of the fossilized pair matches trapped tandems and differs from untrapped tandems. Thus, the fossilized pair likely is a tandem running pair, representing the direct evidence of the mating behavior of extinct termites. Furthermore, by comparing the postures of partners on a sticky surface and in the amber inclusion, we estimated that the male likely performed the leader role in the fossilized tandem. Our results demonstrate that past behavioral interactions can be reconstructed despite the spatial distortion of body poses during fossilization. Our taphonomic approach demonstrates how certain behaviors can be inferred from fossil occurrences.


Assuntos
Isópteros , Humanos , Feminino , Masculino , Animais , Âmbar , Extinção Psicológica , Fósseis , Postura
20.
Sci Rep ; 14(1): 5669, 2024 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-38454093

RESUMO

Squatting is an active posture test used in assessing baroreflex sensitivity, and the array of patients a physiotherapist handles may benefit from this test to avoid the adverse effects of exercise. Therefore, this study is designed to evaluate the effect of squatting on heart rate and blood pressure among undergraduate students. 35 males (mean age = 22.94 ± 1.846) and 40 females (mean age = 22.28 ± 2.075) participated in this experimental study. Demographic data and baseline cardiovascular parameters (blood pressure and heart rate) were taken before exercise. The exercise protocol, the squatting stress test, was done for 2 min, after which post-exercise blood pressure and heart rate were taken at one minute each. A repeated measure ANOVA and independent t-test were used to analyse the difference at the 0.05 alpha level. It was found that there was a significant difference between pre-exercise in lying and squatting post-exercise blood pressure and heart rate in the first and second minutes (p < 0.01), pre-exercise in lying and standing post-exercise blood pressure and heart rate in the first and second minutes (p < 0.01), pre-exercise in standing and standing post-exercise blood pressure and heart rate in the first and second minutes (p < 0.01), and pre-exercise in standing and squatting post-exercise blood pressure and heart rate in the first and second minutes (p < 0.01). Also, there was a significant difference in pre-exercise heart rate between lying and standing (p < 0.05) and not between the first minute and second minute post-squatting or standing exercise systolic blood pressure (p = 0.588) or diastolic blood pressure (p = 0.22-1). In conclusion, squatting trials among undergraduates revealed some statistically significant changes, especially between the cardiopulmonary parameters obtained in a standing position compared to lying and those measured after one minute. Therefore, caution should be observed when administering exercises that require changes in posture.


Assuntos
Barorreflexo , Postura , Masculino , Feminino , Humanos , Adulto Jovem , Adulto , Postura/fisiologia , Pressão Sanguínea/fisiologia , Frequência Cardíaca/fisiologia , Barorreflexo/fisiologia , Estudantes
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