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1.
J Comput Assist Tomogr ; 45(1): 84-92, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33475316

RESUMO

OBJECTIVE: This study aimed to assess the potential of an Ag additional filter attached to the bow tie filter of a computed tomography (CT) scanner to reduce the radiation dose in CT localizer radiography. METHODS: Radiation doses in CT localizer radiography with Cu and Ag additional filters were evaluated based on dose measurements and Monte Carlo simulations. Image quality evaluations of an adult torso phantom were performed, and the automatic exposure control performance was evaluated in terms of the water-equivalent thickness estimated from CT localizer radiographs. RESULTS: With the Ag additional filter, effective doses were approximately 72% to 75% lower than those with the Cu additional filter. The image quality and water-equivalent thickness with the Ag additional filter were similar to those with the Cu additional filter. CONCLUSIONS: The Ag additional filter helped significantly reduce radiation doses in CT localizer radiography while maintaining image quality and performance.


Assuntos
Prata/efeitos adversos , Tomografia Computadorizada por Raios X/instrumentação , Tronco/diagnóstico por imagem , Adulto , Cobre/efeitos adversos , Desenho de Equipamento , Humanos , Método de Monte Carlo , Imagens de Fantasmas , Doses de Radiação , Interpretação de Imagem Radiográfica Assistida por Computador
2.
J Dermatolog Treat ; 32(1): 90-94, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31084382

RESUMO

Background: Vitiligo is an acquired depigmentation skin disorder mainly caused by the destruction of melanocytes. There are many therapeutic options available for vitiligo, but the options are not uniformly effective.Objectives: This study aimed to explore the clinical effect of the autologous non-cultured epidermal cell suspension (NCES) technique in the treatment of patients with stable vitiligo.Methods: A retrospective study of before-after comparisons was undertaken with 41 patients with stable vitiligo who received treatment with the NCES technique. The percentage of repigmentation area was evaluated using image analysis of the appearance before and 6-9 months after operation.Results: A total of 41 patients (18 males and 23 females) with a duration of clinical stability for ranging from 1 to 10 years (mean 1.6 ± 1.9) were included. The mean age was 20.2 years (range, 8-50) and 4 (9.8%) were children under the age of 14 years. After 6-9 months of follow-up, 80.5% (33/41) of the patients showed good response; among these patients, 17.1% (7/41) showed complete or almost complete repigmentation. Interestingly, all 4 children showed very good response (more than 76% repigmentation). There were no significant differences in the efficacy of treatment between the different transplantation areas of the facial neck, trunk, and distal limbs and there were no adverse effects such as infection or scar formation.Limitation: This study included only a single center with a small sample size.Conclusions: Our study shows that the NCES technique has a high therapeutic effect, is safe for patients with stable vitiligo, and may be a very promising potential option for treating children.


Assuntos
Células Epidérmicas/transplante , Vitiligo/terapia , Adolescente , Adulto , Criança , Células Epidérmicas/citologia , Extremidades/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pescoço/patologia , Estudos Retrospectivos , Tronco/patologia , Transplante Autólogo , Resultado do Tratamento , Adulto Jovem
3.
Sports Health ; 13(1): 85-90, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32940548

RESUMO

BACKGROUND: Suspension training systems, which use body weight resistance under unstable conditions, may be effective for muscle strengthening in persons with scapular dyskinesis or subacromial impingement syndrome. HYPOTHESIS: Greater arm, scapular, and trunk muscle recruitment will occur during horizontal abduction row exercises. STUDY DESIGN: Descriptive laboratory study. LEVEL OF EVIDENCE: Level 5. METHODS: Surface electromyography data were collected from 28 participants (14 men, 14 women). A total of 13 right-sided muscles were studied at a sampling frequency of 1000 Hz. Maximal voluntary isometric contractions (MVICs) were established. Participants completed 3 repetitions per exercise in random order. We compared muscle recruitment during 3 rowing exercises: low row, high row, and horizontal abduction row. Data were compared with repeated-measures analyses of variance and post hoc Bonferroni corrections. RESULTS: For high row and horizontal abduction row conditions, the upper, middle, and lower trapezius and posterior deltoid demonstrated >60% MVIC magnitudes of recruitment, and the upper erector spinae demonstrated 40% to 60% MVIC magnitudes of recruitment, respectively. In contrast, in the low row exercise, 40% to 60% MVIC magnitudes of recruitment were observed only in the middle trapezius, latissimus dorsi, and posterior deltoid. CONCLUSION: With the suspension system, high row and horizontal abduction row exercises promote muscle strengthening (>50% MVIC) in the upper, middle, and lower fibers of the trapezius, posterior deltoid, and upper erector spinae. CLINICAL RELEVANCE: Rowing exercises performed with suspension straps may be recommended for muscle strengthening in patients with scapular dyskinesis and subacromial impingement syndrome as well as for healthy persons in need of enhanced scapular muscle performance.


Assuntos
Músculo Esquelético/fisiologia , Treinamento de Resistência/métodos , Ombro/fisiologia , Esportes Aquáticos/fisiologia , Braço/fisiologia , Cotovelo/fisiologia , Eletromiografia , Feminino , Humanos , Contração Isométrica , Masculino , Treinamento de Resistência/instrumentação , Escápula/fisiologia , Escápula/fisiopatologia , Síndrome de Colisão do Ombro/fisiopatologia , Tronco/fisiologia , Adulto Jovem
4.
Am J Sports Med ; 49(1): 183-192, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33381989

RESUMO

BACKGROUND: Core stability is influential in the incidence of lower extremity injuries, including anterior cruciate ligament (ACL) injuries, but the effects of core strength training on the risk for ACL injury remain unclear. HYPOTHESIS: Core muscle strength training increases the knee flexion angle, hamstring to quadriceps (H:Q) coactivation ratio, and vastus medialis to vastus lateralis (VM:VL) muscle activation ratio, as well as decreases the hip adduction, knee valgus, and tibial internal rotation angles. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 48 male participants were recruited and randomly assigned to either the intervention group (n = 32) or the control group (n = 16). Three-dimensional trunk, hip, knee, and ankle kinematic data and muscle activations of selected trunk and lower extremity muscles were obtained while the participants performed side-step cutting. The core endurance scores were measured before and after training. Two-way analyses of variance were conducted for each dependent variable to determine the effects of 10 weeks of core strength training. RESULTS: The trunk endurance scores in the intervention group significantly increased after training (P < .05 for all comparisons). The intervention group showed decreased knee valgus (P = .038) and hip adduction angles (P = .032) but increased trunk flexion angle (P = .018), rectus abdominis to erector spinae coactivation ratio (P = .047), H:Q coactivation ratio (P = .021), and VM:VL activation ratio (P = .016). In addition, the knee valgus angle at initial contact was negatively correlated with the VM:VL activation ratio in the precontact phase (R2 = 0.188; P < .001) but was positively correlated with the hip adduction angle (R2 = 0.120; P < .005). No statistically significant differences were observed in the trunk endurance scores, kinematics, and muscle activations for the control group. CONCLUSION: Core strength training altered the motor control strategies and joint kinematics for the trunk and the lower extremity by increasing the trunk flexion angle, VM:VL activation ratio, and H:Q activation ratio and reducing the knee valgus and hip adduction angles. CLINICAL RELEVANCE: Training core muscles can modify the biomechanics associated with ACL injuries in a side-step cutting task; thus, core strength training might be considered in ACL injury prevention programs to alter the lower extremity alignment in the frontal plane and muscle activations during sports-related tasks.


Assuntos
Músculos Abdominais/fisiologia , Lesões do Ligamento Cruzado Anterior/terapia , Extremidade Inferior/fisiologia , Treinamento de Resistência , Tronco/fisiologia , Adulto , Lesões do Ligamento Cruzado Anterior/prevenção & controle , Fenômenos Biomecânicos , Humanos , Articulação do Joelho , Masculino , Amplitude de Movimento Articular , Fatores de Risco
5.
Clin Dermatol ; 38(6): 757-761, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33341210

RESUMO

Paraviral eruptions, such as the papular-purpuric gloves and socks syndrome or eruptive pseudoangiomatosis, share the following features that distinguish them from a classic viral eruption: they are highly recognizable; the eruption usually lasts a few weeks; many different viruses and sometimes other agents can trigger them; on microscopic examination, there is no specific cytopathogenic viral effect. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can induce both a classic viral eruption and a paraviral eruption, the meaning of which in terms of pathophysiology and prognosis is very different. Some patients infected with coronavirus disease 2019 (COVID-19) have a papulovesicular eruption involving mainly the trunk. Those patients have active viremia, and some have developed pneumonia and died. Biopsy of the eruption revealed cytopathogenic viral effect, and thus there is a direct interaction of the virus with the skin; it is, therefore, a classic viral exanthema. Others, mainly young patients, developed chilblains of the fingers and toes 3 or 4 weeks after minor signs of COVID-19 or after contact with a diseased person. They did not develop severe COVID-19. Biopsy revealed classic findings of chilblains without cytopathogenic viral effect. Most of those patients did not develop specific antibodies. Those chilblains can be considered as paraviral. Classic viral manifestations are the consequence of a direct interaction of the skin with the virus, whereas paraviral manifestations result from the activation of the immune system. In the case of paraviral chilblains, I hypothesize that it is the innate immune system that rejects SARS-CoV-2. Chilblains are also observed in rare monogenic disorders called type 1 interferonopathies, where antiviral innate imunity is abormally activated. This would explain why these individuals do not develop specific antibodies, because they are probably naturally resistant to SARS-CoV-2 infection via their innate immuen system.


Assuntos
/complicações , Pérnio/virologia , Dermatopatias/virologia , Dedos , Humanos , Imunidade Inata , Dermatopatias/patologia , Dedos do Pé , Tronco
6.
PLoS One ; 15(12): e0244019, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33315956

RESUMO

Examiners with minimal training and skill are often called upon to make body composition assessments using field methods. This study compared the interrater reliability of novice examiners for the skinfold (SKF) and A-mode ultrasound (US) methods of body composition assessment. Undergraduate Kinesiology majors (48 males, 32 females) with minimal training took both SKF and US measurements at three sites (males: chest, abdomen, thigh; females: triceps, suprailiac, thigh). Interrater reliability was significantly better for US compared to SKF at the thigh (ICCUS = 0.975, ICCSKF = 0.912) and abdomen (ICCUS = 0.984, ICCSKF = 0.693) for men and suprailiac (ICCUS = 0.978, ICCSKF = 0.883) for women. Additionally, interrater reliability of the US method was superior to the SKF method for the estimate of male body fat percentage (ICCUS = 0.990, ICCSKF = 0.862). The 95% CI was generally narrower for the US method than the SKF method at each site. The interrater reliability of the US method was superior to or equal to the SKF method for measuring subcutaneous body fat when novice examiners took the measurements.


Assuntos
Pregas Cutâneas , Gordura Subcutânea/diagnóstico por imagem , Ultrassonografia/normas , Gordura Abdominal/anatomia & histologia , Gordura Abdominal/diagnóstico por imagem , Adulto , Feminino , Humanos , Masculino , Variações Dependentes do Observador , Gordura Subcutânea/anatomia & histologia , Coxa da Perna/anatomia & histologia , Coxa da Perna/diagnóstico por imagem , Tronco/anatomia & histologia , Tronco/diagnóstico por imagem
7.
PLoS One ; 15(10): e0236205, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33095774

RESUMO

The present research aims at quantifying the impact of practicing a new coordination pattern with an online visual feedback on the postural coordination performed on a mechanical horse. Forty-four voluntary participants were recruited in this study. They were randomly assigned to four practice groups based on i) with or without feedback (i.e., group 1, control, did not receive the feedback; group 2, 3 and 4 received an online feedback during practice) and ii) the specific trunk/horse coordination to target during practice (group 1, target coordination = 180° (without feedback); group 2, target coordination = 0°; group 3, target coordination = 90°; group 4, target coordination = 180°). All participants performed pre-, practice, post- and retention sessions. The pre-, post- and retention sessions consisted of four trials, with one trial corresponding to one specific target coordination to maintain between their own oscillations and the horse oscillations (spontaneous, 0°, 90°, and 180°). The practice phase was composed of three different sessions during which participants received an online feedback about the coordination between their own oscillations and the horse oscillations. Results showed a significant change with practice in the trunk/horse coordination patterns which persisted even after one month (retention-test). However, all the groups did not show the same nature of change, evidenced by a high postural variability during post-test for 0° and 90° target coordination groups, in opposition to the 180° and spontaneous groups who showed a decrease in coordination variability for the 180° group. The coordination in anti-phase was characterized as spontaneously adopted by participants on the mechanical horse, explaining the ease of performing this coordination (compared to the 0° and 90° target coordination). The effect of online visual feedback appeared not only on the coordination pattern itself, but most importantly on its variability during practice, including concerning initially stable coordination patterns.


Assuntos
Retroalimentação , Atividade Motora/fisiologia , Equilíbrio Postural , Prática Psicológica , Desempenho Psicomotor , Postura Sentada , Adolescente , Adulto , Animais , Atenção , Fenômenos Biomecânicos , Cavalos , Humanos , Sistemas On-Line , Tronco , Adulto Jovem
8.
Artigo em Inglês | MEDLINE | ID: mdl-33018484

RESUMO

In this study, we investigated the feasibility of computationally reconstructing the 3D geometry of the stomach by performing source localization of the magnetic field (MF) induced from the stomach surface. Anatomically realistic stomach and torso models of a human participant, reconstructed from the CT images, were used in the computations. First, 128 coils with a radius of 5 mm were positioned on different locations on the stomach model. Next, MF at the sensor positions were computed using Bio-Savart law for the currents of 10 and 100 mA. Then, three noise levels were defined using the biomagnetic data recorded from the same participant and two additional sets of generated white-noise resulting in mean signal to noise ratios (SNR) of 20 and 10 dB. Finally, for each combination of the current and noise level, the magnetic dipole (MDP) approximation was performed to estimate coil positions. The performance of the source localization was assessed by computing the goodness of fit (GOF) values and the distance between the coil and the estimated MDP positions. We obtained GOF values over 98% for all coils and a mean localization error of 0.69±0.08 mm was achieved when 100 mA current was used to induce MF and only biomagnetic data was added. When additional white-noise was added, the GOF values decreased to 95% and the mean localization error increased to around 4 mm. A current of 10 mA was enough to localize the coil positions with a mean error around 8 mm even for the highest noise level we tested but for the few coils furthest from the body surface, the error was around 10 cm. The results indicate that source localization using the MDP approximation can successfully extract spatial information of the stomach.Clinical relevance-Extracting the spatial information of the stomach during the recording of the slow wave activity provides new insights in assessing gastric recordings and relating to disorders.


Assuntos
Campos Magnéticos , Estômago , Humanos , Magnetismo , Estômago/diagnóstico por imagem , Tronco
9.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3743-3746, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018815

RESUMO

After a hemiparetic stroke, the contralesional upper limb is left with significant motor impairments including: weakness, spasticity, and abnormal joint torque patterns resulting in the flexion synergy (i.e. abnormal coupling between shoulder abduction and elbow/wrist and finger flexion). These impairments, and in particular the flexion synergy, limit ability to reach to the full extent of their limb workspace. Motor control of the trunk is also altered post stroke, with compromised ability to stabilize the trunk and excessive trunk movement during reaching, abnormal isometric torque coupling patterns in the transverse and sagittal planes and weakness. These motor impairments in both trunk and arm limit their ability to perform activities of daily living. While the effect of stroke on reaching has been studied extensively, less is known about the impact of deficits in trunk motor control on reaching ability and the impact of the flexion synergy on trunk postural control. Methods for investigating altered trunk control, specifically during a reach when concurrent loads that elicit the flexion synergy are imposed on the limb and trunk, are limited. Specifically, trunk deficits have yet to be studied in the context of the flexion synergy whereby loads imposed on the arm to elicit shoulder abduction have a negative impact on reaching and potentially on trunk posture. In order to address this gap, we developed a system that integrates a robotic device to simulate varied reaching environments, surface electromyography to measure primary trunk and arm muscle activity, and a two-camera motion capture system that uses reflective markers to measure trunk and arm movement. Feasibility and usability of the system was established during evaluation of reaching ability with varying levels of shoulder abduction loads while the trunk is either restrained or unrestrained in two participants with stroke and a healthy control.Clinical Relevance- The system presented here is capable of monitoring changes in trunk postural control after a hemiparetic stroke during a reaching task as a first step in furthering our understanding of changes in trunk motor control during reaching with the goal of developing more targeted and effective interventions for stroke rehabilitation.


Assuntos
Atividades Cotidianas , Acidente Vascular Cerebral , Humanos , Paresia , Amplitude de Movimento Articular , Acidente Vascular Cerebral/complicações , Tronco
10.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 4038-4041, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018885

RESUMO

The current work presents the development and technical validation, in terms of accuracy and latency, of a low-cost portable device that allows identifying possible risks of falling in people when they realize spinal trunk lateral movements. The device is comprised of an Inertial Measurement Unit (IMU) located on the lower back. Measurements are processed to get meaningful parameters such as rotation angles of the back when realizing lateral movements. In order to give performance feedback while doing the test, this device includes a Microcontroller as Raspberry Pi to return visual feedback to the person. The critical system feature is the latency of the system since getting the data of a movement until showing that on the feedback screen. For that reason, before to start assessing people, we propose a technical method using the Mikrolar Hexapod Robot R3000 for validating the system developed by simulating the movement of the back and recording it with a video camera to apply an offline Motion-to-Photon Latency analysis.


Assuntos
Movimento , Tronco , Retroalimentação Sensorial , Movimento (Física) , Coluna Vertebral
11.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 4156-4159, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018913

RESUMO

The aim of this work is to implement and validate an automated method for the localization of body-worn inertial sensors. Often, body-sensor networks with inertial measurement units (IMU) used in rehabilitation and ambient monitoring of patients with movement disorders, require specific markings or labels for the correct body placement. This introduces a burden, which, especially for ambient monitoring, could lead to errors or reduced adherence. We propose a method to automatically identify sensors attached on a predefined set of body placements, namely, wrists, shanks and torso. The method was used in a multi-site clinical trial with Parkinson's disease patients and in 45 sessions it identified sensor placement on torso, wrists and shanks with 100% accuracy, discriminated between left and right shank with 100% accuracy and between left and right wrist with 98% accuracy. This is remarkable, considering the presence of parkinsonian motor symptoms causing abnormal movement patterns, such as dyskinesia.Clinical Relevance- This method can facilitate home monitoring of patients with movement disorders.


Assuntos
Discinesias , Doença de Parkinson , Postura , Dispositivos Eletrônicos Vestíveis , Automação , Humanos , Tronco , Punho
12.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 4596-4599, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33019017

RESUMO

Walking speed (WS) is recognized as an important dimension of functional health and a candidate endpoint for clinical trials. To be adopted as a powerful outcome measure in clinical assessment, WS should be estimated pervasively and accurately in the real-life context. Although current state of the art points to possible solutions, e.g., by using pairing of wearable sensors with dedicated algorithms, the accuracy and robustness of existing algorithms in challenging situations should be carefully considered. This study highlights the main methodological issues for WS estimation using single inertial sensor fixed on trunk (chest/low back) and data recorded in a sample of stroke patients with impaired mobility.


Assuntos
Marcha , Acidente Vascular Cerebral , Algoritmos , Humanos , Tronco , Velocidade de Caminhada
13.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 4823-4826, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33019070

RESUMO

In this work, we quantify the neck's involvement in stabilizing the head during falls in older adults to avoid head impacts. We tracked kinematics of 12 real-world backward falls in long-term care captured on video, where head impact was avoided. We estimated dynamic spring-dashpot parameters of the neck and hip representing active muscle activity and passive tissue structures. Neck stiffness, damping, and target posture averaged 24.00±6.17Nm/rad, 0.38±0.16Nms/rad, and 76.2±14.7° flexion respectively. The stiffness and target posture suggest that residents actively contracted their neck muscles to maintain the head upright. Our results shed light on the importance of neck strength for avoiding head impact during a fall.Clinical Relevance-Falls account for 80% of traumatic brain injuries in adults 65+ years. While upper limb bracing can reduce the risk of head impacts during a fall in young adults, this protective response is less effective in older adults living in longterm care. Understanding how the neck and torso musculature are used to avoid head impact can guide the design of therapeutic exercise programs and assistive or protective devices.


Assuntos
Acidentes por Quedas , Cabeça , Acidentes por Quedas/prevenção & controle , Idoso , Humanos , Pescoço , Músculos do Pescoço , Tronco , Adulto Jovem
14.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 5806-5809, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33019294

RESUMO

The customized design of braces for adolescent idiopathic scoliosis (AIS) treatment requires the acquisition of the 3D external geometry of the patients' trunks. Three body scanning systems are available at CHU Sainte-Justine in Montreal: a fixed system of InSpeck Capturor II LF digitizers and two portable scanners, BodyScan and Structure Sensor. The aim of this study is to compare them by evaluating their accuracy and repeatability. To achieve this, we placed 46 surface markers on an anthropomorphic manikin and scanned it three times with each system. We also measured the 3D coordinates of the same markers using a coordinate measuring machine (CMM), serving as ground-truth. We evaluated the repeatability and accuracy of the three systems: the former, by measuring the bidirectional mean distance between the three surfaces acquired with a given modality; the latter, by calculating the residual normal distance separating each of the 3D surfaces and the CMM point cloud. We also compared texture mapping accuracy between InSpeck and Structure Sensor by examining the CMM point cloud versus the marker 3D coordinates selected on the trunk surface. The results show good accuracy and repeatability for all three systems, with slightly better geometric accuracy for BodyScan (p-value ≈ 10-6). In terms of texture mapping, InSpeck showed better accuracy than Structure Sensor (p-value = 0.0059).


Assuntos
Imageamento Tridimensional , Escoliose , Adolescente , Braquetes , Humanos , Aparelhos Ortodônticos Fixos , Tronco
15.
Sports Biomech ; 19(6): 723-737, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32942954

RESUMO

The aim of this study was to understand if and how surface-induced vibrations and road bike damping affect short-term neuromuscular performance in cycling. Thirty cyclists (mass 75.9 ± 8.9 kg, height 1.82 ± 0.05 m, Vo2max 63.0 ± 6.8 ml/min/kg) performed steady-state and maximum effort tests with and without vibration exposure (front dropout: 44 Hz, 4.1 mm; rear dropout: 38 Hz, 3.5 mm) on a damped and a nondamped bike. Transmitted accelerations to the musculoskeletal system, activation of lower extremity muscles (gast. med., soleus, vast. med., rec. fem.) and upper body muscles (erec. spinae, deltoideus, tric. brachii), oxygen uptake, heart rate and crank power output were measured. The main findings indicate a transmission of vibration to the whole body, but since no major propulsive muscles increase their activation with vibration, the systemic energy demand increases only marginally with vibration. Damping reduces vibrations at the upper body, which indicates an increase in comfort, but has no effect on the vibration transfer to the lower extremities. Therefore, road bike damping does not affect neuromuscular response of the propulsive muscle groups and energy demand. Consequently, short-term power output does not increase with damping.


Assuntos
Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Meio Ambiente , Músculo Esquelético/fisiologia , Vibração , Aceleração , Fenômenos Biomecânicos , Estudos Transversais , Frequência Cardíaca/fisiologia , Humanos , Extremidade Inferior/fisiologia , Masculino , Músculo Esquelético/inervação , Consumo de Oxigênio/fisiologia , Tronco/fisiologia , Extremidade Superior/fisiologia
16.
Maturitas ; 139: 49-56, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32747040

RESUMO

OBJECTIVES: The present experiment examined the role of age and fall history in upper body accelerations when walking on an even and on an uneven surface. STUDY DESIGN: An observational cross-sectional study. MAIN OUTCOME MEASURES: The magnitude (root mean square [RMS]), symmetry (harmonic ratio) and attenuation (attenuation coefficient) of upper body accelerations were quantified as primary outcomes; gait spatiotemporal parameters were measured as secondary outcomes. METHODS: Twenty young adults (mean ± SD age: 29.00 ± 4.51 yrs), 20 older non-fallers (66.60 ± 5.43 yrs) and 20 older fallers (68.55 ± 4.86 yrs) walked on an even and on an uneven surface, while wearing four accelerometers attached to the forehead, pelvis, right and left shanks. RESULTS: Older fallers exhibited increased RMS acceleration in the mediolateral direction at the pelvis level compared with young adults when walking on the even surface (0.18 ± 0.04 vs. 0.14 ± 0.02, respectively), whereas walking on an uneven surface was associated with reduced magnitude of acceleration in older fallers (0.19 ± 0.04) compared with non-fallers (0.23 ± 0.04) and young adults (0.22 ± 0.03). Among other changes, walking on the uneven surface diminished pelvis-to-head attenuation in the mediolateral direction in older fallers (38.07 ± 14.51) compared with non-fallers (50.96 ± 11.03) and young adults (62.62 ± 8.21; all ps<0.05). CONCLUSIONS: Reduced mediolateral accelerations in older fallers when walking on the uneven surface can be interpreted as a compensatory mechanism to preserve stability through increased body stiffness. Reduced postural flexibility in the frontal plane compromises the central role of the trunk in minimizing the impact of gait-related oscillations to the head, as evidenced by reduced mediolateral attenuation in older fallers.


Assuntos
Acidentes por Quedas , Tronco/fisiologia , Caminhada/fisiologia , Aceleração , Adolescente , Adulto , Idoso , Estudos Transversais , Feminino , Humanos , Pessoa de Meia-Idade , Equilíbrio Postural , Adulto Jovem
17.
PLoS One ; 15(7): e0235555, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32645111

RESUMO

The aim of the study was to compare the effects of a 10-week chest-press resistance training on lifting regions in a trained exercise and a none-trained exercise; the barbell bench press (BBP). Thirty-five resistance trained men with 4.2 (± 2.3) years of resistance training experience were recruited. The participants were randomized to attend a resistance program, performing the chest-press, twice per week using either, Smith machine, dumbbells or laying on Swiss ball using a barbell. A six-repetitions maximum (6RM) test was conducted pre- and post-training in the trained chest-press exercise and non-trained BBP to examine lifting velocity, load displacement and the time of the pre-sticking, sticking and post-sticking regions. Additionally, the muscle activity in pectoralis major, triceps brachii, biceps brachii and deltoid anterior was examined. In the post-test, all three chest-press groups decreased lifting velocity and increased the time to reach the sticking- and post-sticking region. Independent of the type of chest-press exercise trained, no differences were observed in vertical displacement or in the muscle activity for the three lifting regions. In general, similar changes in kinematics in trained exercise and those observed in the BBP were observed for all three groups. This indicates that none of the three chest-press exercises (Swiss ball, Smith machine or dumbbells) were specific regarding the lifting regions but displaced a transferability towards the non-trained BBP. However, improved strength altered the sticking region among resistance trained men.


Assuntos
Músculo Esquelético/fisiologia , Treinamento de Resistência/métodos , Fenômenos Biomecânicos , Humanos , Masculino , Tronco/fisiologia , Levantamento de Peso/fisiologia , Adulto Jovem
19.
J Sports Sci ; 38(20): 2367-2373, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32608344

RESUMO

The lateral tilt of the arms accompanied by trunk lateral tilt is a typical blocking manoeuvre in volleyball. However, during this unanticipated blocking movement, an associated risk of ACL injury may result. The aim of the present study was to compare associative ACL risk factors at the initial contact and the first and second peak of VGRF during an unanticipated blocking movement with different arm positions. Synchronized kinematic and kinetic data were collected for each trial of each condition. Student paired t-tests and effect size were used to determine differences between two conditions (S - with arms straight up from the body) and (T - with the arms and trunk laterally tilted). The results showed that the T condition significantly decreases knee flexion, increases VGRF at the foot contact, first peak force and increases the valgus moment at the first peak force. The values of the associated risk factors for a non-contact ACL injury appear to be related to the tilted arm position accompanied by trunk tilt towards to right lower limb during landing. The players should be taught to land with greater knee flexion and, if possible, a double-leg landing to decrease right lower limb loading during the blocking manoeuvre.


Assuntos
Lesões do Ligamento Cruzado Anterior/fisiopatologia , Movimento/fisiologia , Voleibol/fisiologia , Adolescente , Braço/fisiologia , Fenômenos Biomecânicos , Feminino , Humanos , Cinética , Joelho/fisiologia , Tutoria , Destreza Motora/fisiologia , Condicionamento Físico Humano/fisiologia , Fatores de Risco , Estudos de Tempo e Movimento , Tronco/fisiologia
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