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Background: The aim was to analyze changes in normal functional parameters of gait analysis by aging, sex, and body mass index (BMI). Methods: A cross-sectional study with a consecutive sample of asymptomatic subjects was performed between 2014 and 2020. Primary outcomes were time and force parameters (contact time and center of force [CoF] time), in the heel, midfoot, and metatarsal areas, measured using an in-office force platform. Results: A total of 156 subjects (312 feet) were included, including 67% of women with a mean age of 47 years. The mean of total contact time was similar in males and females (P = .695) and across BMI (P = .413). Contact time did not show differences by region (P = .648 heel, P = .286 midfoot, and P = .690 metatarsal). CoF time in the heel and metatarsal areas did not change between males and females (P = .288 and P = .879, respectively); meanwhile, it was different in midfoot (P = .002). Maximum force showed a reduction between sexes in the heel (P = .039) but did not in the midfoot and metatarsal areas. By age, differences were detected in the heel and metatarsal areas in females (P = .002 and P = .001) and the metatarsal area in males (P = .001). According to the age groups, total contact time increased in females (P = .001) but not in males (P = .018), and no differences were detected between foot areas. In females, CoF time did not change either foot areas or age groups. In males, CoF time values increased in the midfoot area in the older group (P = .001). Conclusion: Time variables did not change by foot region, independent of age, sex, and BMI. Heel maximum force decreased in females, probably linked to adaptive phenomena by aging. The midfoot remains stable, and acts as an undamaged "bridge." These parameters could be interpreted as normal in asymptomatic subjects. Level of Evidence: Level III, diagnostic and prognostic.

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SUMMARY: As it is currently played, volleyball is a game in which success depends in large measure on the athleticism of the participants. The aim of this research was to point out the importance of the cycle of stretching and shortening in different jumps for elite volleyball players. Thus, it is common for volleyball athletes to place considerable emphasis on jump training. Not surprisingly, overload injuries of the knee and ankle joints, both acute and chronic, occur frequently among volleyball players and are related to the volume of jump training and skill repetition. Understanding the biomechanics of jumping is therefore a prerequisite for designing effective training programs which minimize the risk of overuse injuries that may result from excessive jumping, and the repetitive mechanical loading of muscles and joints that are involved in jump training Muscles acting about a joint function naturally through a combination of eccentric (lengthening) and concentric (shortening) activations. In the lower limb, the stretch-shortening cycle is a reflex arc in which the tendomuscular system acting about the knee or ankle is eccentrically preloaded (stretched) in the loading or impact phase of the jump before concentrically shortening in the push-off or take-off phase.

RESUMEN: Actualmente, el voleibol es un juego en el que el éxito depende en gran medida del atletismo de los participantes. El objetivo de esta investigación fue señalar la importancia del ciclo de estiramiento y acortamiento en diferentes saltos para jugadores de voleibol de élite. Es común que los atletas de voleibol pongan un énfasis considerable en el entrenamiento de salto. No es sorprendente que las lesiones por sobrecarga de las articulaciones de la rodilla y el tobillo, tanto agudas como crónicas, ocurran con frecuencia entre los jugadores de voleibol y estén relacionadas con el volumen de entrenamiento de saltos y la repetición de destrezas. Comprender la biomecánica del salto es, por lo tanto, un requisito previo para diseñar programas de entrenamiento efectivos que minimicen el riesgo de lesiones por uso excesivo que pueden resultar de un salto excesivo y la carga mecánica repetitiva de los músculos y las articulaciones que están involucrados en el entrenamiento del salto. Los músculos que actúan sobre una articulación funcionan de forma natural a través de una combinación de activaciones excéntricas (alargamiento) y concéntricas (acortamiento). En el miembro inferior, el ciclo de estiramiento-acortamiento es un arco reflejo en el que el sistema tendomuscular que actúa sobre la rodilla o el tobillo se precarga (estira) excéntricamente en la fase de carga o impacto del salto antes de acortarse concéntricamente en el despegue o toma. -fase de apagado.

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Perception of external loads may be a central topic to understand adjustments to the mechanical demands during movement. Nevertheless, the association between the perceived and the real load received is still controversial. This study aimed to correlate vertical ground reaction force (vGRF) to the perception of impact in different regimens of stimulus application. Ten physically active men performed drop jumps from four different heights (0.20, 0.40, 0.60 and 0.80 m). A force plate measured the vGRF, while perception of impact was evaluated through Borg's Ratings of Perceived Exertion. Higher values of maximum vGRF (Fy_max) and impulse of the first 50 ms (I_50), and reduced time to reach Fy_max indicate increased external forces as drop jump height raised. Perception of impact increased gradually with increasing jump height for I_50. Fy_max and I_50 showed moderate to strong correlations to perceived load for 70% and 90% of participants, respectively. Higher and different intensity of stimulus facilitated the perception of impact, presenting moderate to strong correlations to kinetic parameters related to external load during landing from drop jump. Perception of higher impacts could be used as a surrogate to monitor 'real' impacts and possibly also for managing impact-related injury risk.

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OBJECTIVES: To evaluate the clinical characteristics, ground reaction force (GRF), and function of the plantar muscles and dorsiflexors of the ankle in runners with and without Achilles tendinopathy (AT) and in non-runners. METHODS: Seventy-two participants (42 men, 30 women; mean age: 37.3±9.9 years) were enrolled in this cross-sectional study and divided into three groups: AT group (ATG, n=24), healthy runners' group (HRG, n=24), and non-runners' group (NRG, n=24). Both ankles were evaluated in each group. The American Orthopedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale was used for clinical and functional evaluation. GRF was evaluated using force plates and muscle strength was evaluated using an isokinetic dynamometer. RESULTS: The AOFAS scores were lower in the ATG. The strike impulse was higher in the ATG than in the HRG and NRG. However, GRF was similar among the groups. The ATG exhibited lower total work at 120°/s speed than the HRG. The peak torque in concentric dorsiflexion was lower in the NRG than in the ATG and HRG. The peak torque and total work in concentric plantar flexion were lower in the NRG than in the ATG. The peak torque and total work in eccentric plantar flexion were lower in the NRG than in the ATG and HRG. CONCLUSION: Runners with AT showed higher strike impulse, lower muscle strength of the plantar flexors, and higher clinical and functional damage.

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BACKGROUND: Down Syndrome (DS) is a genetic condition presenting delay in acquisition of main motor milestones, such as walking. Although studies have been investigating the biomechanical parameters during land walking performed by individual with DS, the literature is scarce regarding kinetic parameters analysis in this population, specially during water walking. RESEARCH QUESTION: This study sought to assess the vertical ground reaction force (Fz) of walking performed in water and on land at different speeds by individuals with DS. METHODS: Fourteen adults with DS (age: 27.9 ± 7.9 years; body mass: 58.4 ± 12.9 kg; height: 1.4 ± 0.1 m, body mass index: 29.2 ± 5.4 kg.m-2) completed two sessions of data collection, one on land and another in aquatic environment. The protocol consisted of walking performed at three self-selected speeds (slow, comfortable and fast) in randomized order. The Fz was assessed with a waterproof force plate in each condition. Two-way repeated-measures ANOVA (environment and speed), with Bonferroni's post hoc tests, were used for analysis. A significance level was set as α = 0.05. RESULTS: Significant differences were observed between environments (p < 0.001), with reduced first peak of Fz (68-73%), second peak of Fz (66-70%), loading rate (75-78%) and impulse (40-41%) in the water walking for all speeds analyzed. In the aquatic environment, no significant difference was observed for the first and second Fz peaks with the increasing speed of walking. Moreover, the loading rate significantly increased (p = 0.019) as the impulse significantly reduced (p < 0.001) in the higher speeds. SIGNIFICANCE: Individuals with DS present reduced Fz outcomes during water walking in comparison to land. Therefore, water walking may be performed by individuals with DS with safe vertical loads on lower limbs regardless the self-selected speed for rehabilitation, correction of gait and training purposes.

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This paper presents the development of a smart carpet based on polymer optical fiber (POF) for ground reaction force (GRF) and spatio-temporal gait parameter assessment. The proposed carpet has 20 intensity variation-based sensors on one fiber with two photodetectors for acquisition, each one for the response of 10 closer sensors. The used multiplexing technique is based on side-coupling between the light sources and POF lateral sections in which one light-emitting diode (LED) is activated at a time, sequentially. Three tests were performed, two for sensor characterization and one for validation of the smart carpet, where the first test consisted of the application of calibrated weights on the top of each sensor for force characterization. In the second test, the foot was positioned on predefined points distributed on the carpet, where a mean relative error of 2.9% was obtained. Results of the walking tests on the proposed POF-embedded smart carpet showed the possibility of estimating the GRF and spatio-temporal gait parameters (step and stride lengths, cadence, and stance duration). The obtained results make possible the identification of gait events (stance and swing phases) as well as the stance duration and double support periods. The proposed carpet is a low-cost and reliable tool for gait analysis in different applications.

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BACKGROUND: A slip occurs when the required friction (RCOF) to prevent slipping at the foot/floor interfaces exceeds the available friction. The RCOF is dependent upon the biomechanics features of individuals and their gait. On the other hand, the available friction depends on environmental features. Once individuals with crouch gait have their biomechanics of gait completely altered, how do they interact with a supporting surface? The aim was to quantify the RCOF in children with bilateral spastic cerebral palsy (BSCP) and crouch gait. METHODS: 11 children with crouch gait and 11 healthy age-matched children were instructed to walk barefoot at self-selected speed over a force platform. The RCOF curve was obtained as the ratio between the tangential forces (FT), and the vertical ground reaction force (FZ). Three points were extracted by the RCOF, FT and FZ curves at the loading response, midstance and push-off phases. FINDINGS: Children with BSCP presented higher values of RCOF in all support phase and lower gait velocity relative to the healthy controls. For BSCP group no correlation between FT and FZ were found, indicating that this group is not able to negotiate the forces during the support phase. INTERPRETATION: Children with BSCP and crouch gait are not able to negotiate the forces applied on the ground in support phase, so to avoid the fall, their strategy is to reduce the gait velocity.

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AbstractIntroduction: The maintenance of balance and body orientation during standing is essential to perform different activities. One of the devices used to measure balance them is the force platform. This device measures the ground reaction force (GRF) and displacement of the center of pressure (COP), both biomechanical parameters involved in human motion. This article proposes a new design for non-commercial low-cost force platforms for scientific research purposes. Methods for calibration and validation are also described. Methods A force platform, developed according to International Standards of Measurement and dedicated to measuring feet contact forces was built for approximately one tenth of the cost of commercial platforms. Calibration was performed by loading known masses, centralized or distributed, on the platform. An experimental study was conducted with four volunteers in different conditions to validate and verify the practical applicability of the device. Results The platform calibration showed an adequate connectivity, linearity and reliable measurement of the variables proposed in this research, being suitable for studies of human postural behavior. Conclusion Based on the validation results, we believe the low-cost platform can be used as stabilometric device to measure postural control and balance in clinical or sports experiments. However future studies will be required to provide a final validation and compare its performance with other force platforms.

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The aim of this study was to determine the effect of the time between measures on ground reaction force running variability; 15 healthy men (age = 23.8 ± 3.7 years; weight = 72.8 ± 7.7 kg; height 174.3 ± 8.4 cm) performed two trials of running 45 minutes at 9 km/hr at intervals of seven days. The ground reaction forces were recorded every 5 minutes. The coefficients of variation of indicative parameters of the ground reaction forces for each condition were compared. The coefficients of variations of the ground reaction forces curve analyzed between intervals and sessions were 21.9% and 21.48%, respectively. There was no significant difference for the ground reaction forces parameters Fy1, tFy1, TC1, Imp50, Fy2, and tFy2 between intervals and sessions. Although the ground reaction forces variables present a natural variability, this variability in intervals and in sessions remained consistent, ensuring a high reliability in repeated measures designs.

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BACKGROUND: The use of bandages improves quasi-static posture control in individuals with knee osteoarthritis, but it is unknown whether this increased sensory input influences postural control in dynamic tasks. OBJECTIVE: Assess the effect of bandage use on motor performance and reported pain in individuals with knee osteoarthritis during obstacle crossing. METHODS: Twenty-four individuals with knee osteoarthritis were enrolled. A force plate was used to measure the vertical and anterior-posterior components of the ground reaction force during obstacle crossing, for the trailing and leading legs, under conditions with and without the use of a bandage. Pain was assessed using the visual analogue scale. RESULTS: With use of a bandage, the propulsive time, time to active peak, propulsive peak, passive peak, and active impulse were significantly reduced in the trailing leg, and the braking peak was significantly increased in the leading leg. The pain parameters did not exhibit any variation. CONCLUSIONS: These results suggest that the use of a bandage allowed for a more rapid movement, better estimates of the force applied against the ground in the propulsive stage, and a reduction in the overload on the locomotor system in the loading response stage.

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The aim of this study was to present a new training algorithm using artificial neural networks called multi-objective least absolute shrinkage and selection operator (MOBJ-LASSO) applied to the classification of dynamic gait patterns. The movement pattern is identified by 20 characteristics from the three components of the ground reaction force which are used as input information for the neural networks in gender-specific gait classification. The classification performance between MOBJ-LASSO (97.4%) and multi-objective algorithm (MOBJ) (97.1%) is similar, but the MOBJ-LASSO algorithm achieved more improved results than the MOBJ because it is able to eliminate the inputs and automatically select the parameters of the neural network. Thus, it is an effective tool for data mining using neural networks. From 20 inputs used for training, MOBJ-LASSO selected the first and second peaks of the vertical force and the force peak in the antero-posterior direction as the variables that classify the gait patterns of the different genders.

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OBJECTIVES: To investigate the relationships between the perception of comfort and biomechanical parameters (plantar pressure and ground reaction force) during running with four different types of cushioning technology in running shoes. DESIGN: Randomized repeated measures. METHODS: Twenty-two men, recreational runners (18-45 years) ran 12km/h with running shoes with four different cushioning systems. Outcome measures included nine items related to perception of comfort and 12 biomechanical measures related to the ground reaction forces and plantar pressures. Repeated measure ANOVAs, Pearson correlation coefficients, and step-wise multiple regression analyses were employed (p≤0.05). RESULTS: No significant correlations were found between the perception of comfort and the biomechanical parameters for the four types of investigated shoes. Regression analysis revealed that 56% of the perceived general comfort can be explained by the variables push-off rate and pressure integral over the forefoot (p=0.015) and that 33% of the perception of comfort over the forefoot can be explained by second peak force and push-off rate (p=0.016). CONCLUSIONS: The results did not demonstrate significant relationships between the perception of comfort and the biomechanical parameters for the three types of shoes investigated (Gel, Air, and ethylene-vinyl acetate). Only the shoe with Adiprene+ technology had its general comfort and cushioning perception predicted by the loads over the forefoot. Thus, in general, one cannot predict the perception of comfort of a running shoe through impact and plantar pressure received.

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Patellofemoral pain syndrome (PFPS) is a prevalent clinical condition and it affects gait behavior. Braking and propulsive impulses are important biomechanical parameters obtained from ground reaction forces (GRF), which combine the amount of force applied over a period of time. The aim of this study was to evaluate these impulses while walking up and down stairs in healthy controls and PFPS individuals. The results did not reveal significant differences in braking and propulsive impulses between groups during these activities. Thus, the painful condition on a simple functional activity was insufficient to change the motor strategy to walking up or down the stairs...

"Análise dos impulsos de frenagem e de propulsão em indivíduos com síndrome da dor femoropatelar durante subida e descida de degraus." A síndrome da dor femoropatelar (SDFP) é uma condição clínica prevalente e que afeta o comportamento da marcha. Impulsos de frenagem e propulsão são importantes parâmetros biomecânicos obtidos a partir da força de reação do solo que combinam a quantidade de força aplicada sobre um período de tempo. O objetivo deste estudo foi avaliar esses impulsos durante a subida e descida de degraus em indivíduos controle saudáveis e com SDFP. Os resultados não revelaram diferenças significativas nos impulsos de frenagem e propulsão entre os grupos durante essas atividades. Assim, a condição dolorosa em uma atividade funcional simples foi insuficiente para modificar a estratégia motora de descer ou subir degraus...

"Análisis de los impulsos de frenado y propulsión en la personas con síndrome de dolor patelofemoral durante la actividad de subir y bajar un escalón." El Síndrome de dolor patelofemoral (SDPF) es una condición médica prevalente que afecta al comportamiento de la marcha. Impulso de propulsión y de frenado son parámetros biomecánicos importantes obtenidos a partir de la fuerza de reacción del suelo que combinan la cantidad de fuerza aplicada durante un período de tiempo. El objetivo del estudio fue evaluar estos impulsos durante las actividades de subir y bajar un escalón en sujetos sanos y con SDP. Los resultados no mostraron diferencias significativas en los impulsos de frenado y propulsion entre los grupos durante las actividades. Por lo tanto, Por lo tanto, la condición dolorosa en una actividad funcional simple, no fue suficiente para cambiar la estratégia de subir y bajar un escalón...

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O objetivo do presente estudo foi comparar a absorção de impacto durante a marcha descalço e com tênis e coturno fornecidos pelo Exército Brasileiro. A amostra foi composta por 20 soldados saudáveis recém-incorporados sem sintomas ou lesões musculoesqueléticas ou neurológicas que interferissem na marcha. Os sujeitos foram instruídos a caminhar em uma plataforma de madeira de 10 metros de comprimento por um metro de largura, com duas plataformas de força (Bertec, EUA) embutidas no centro. O componente vertical da força de reação do solo foi avaliado durante a marcha nas situações tênis, coturno e descalço. O sistema de cinemetria (Qualysis, Suécia) foi utilizado para medir a velocidade da marcha em cada situação de teste. O primeiro pico de força (PPF), o tempo para atingir o PPF (T_PPF), pico transiente de impacto (IPF) e a taxa de aceitação do peso (TAP) entre 10% e 30%, 30% e 50%, 50% e 70%, 70% e 90% e 10% e 90% do PPF foram avaliadas. O T_PPF foi em média 1s menor (p < 0,0001), o IPF e a TAP entre 10% e 30% do PPF foram maiores (p < 0,0001, ambos) descalço comparados a marcha com tênis e coturno. Não foi observado diferença estatística nas outras variáveis estudadas nas três condições de teste, bem como em nenhuma variável na comparação entre tênis e coturno. Os calçados avaliados são eficientes em reduzir o impacto durante a marcha por atrasar em média 1 s o tempo em que o PPF foi atingido, reduzir o IPF e a TAP nos primeiros 30% do PPF

This study aimed at comparing shock absorption during gait while walking barefoot, tennis shoes and military boots. Twenty healthy soldiers without neurologic or musculoskeletal disorders were evaluated. Subjects walked 10 meters along a straight and level walkway at a comfortable speed in barefoot condition and using tennis shoes and military boots. Two force platforms (Bertec, EUA) were placed in serial at the middle of the walkway used to measure the ground reaction forces (GRF). The kinematic system (Qualysis, Sweden) was used to measure gait speed in each test condition. The first peak of force (FPF) of the vertical component of the GRF, time to reach to FPF (T_FPF), transient impact peak force (IPF) were evaluated and the weight acceptance rate at 10% to 30%, 30% to 50%, 50% to 70%, 70% to 90% and 10% to 90% of FPF. T_FPF was 1 s shorter (p < 0.0001), as well as IPF and weight acceptance rate at 10% to 30% in barefoot was higher (p < 0.0001, both) than tennis shoes and military boots gait patterns. None statistical difference was found in the others analyzed variables, even as in the tennis shoes and military boots comparisons. The analyzed footwear delayed the FPF impact during gait, reduce the IPF and the weight acceptance phase during 10% to 30% of FPF, being efficient in reduce impact forces during gait

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PURPOSE: To determine if heel height alters vertical ground reaction forces (vGRF) when landing from a forward hop or drop landing. BACKGROUND: Increased vGRF during landing are theorized to increase ACL injury risk in female athletes. METHODS: Fifty collegiate females performed two single-limb landing tasks while wearing heel lifts of three different sizes (0, 12 & 24 mm) attached to the bottom of a athletic shoe. Using a force plate, peak vGRF at landing was examined. Repeated measures ANOVAs were used to determine the influence of heel height on the dependent measures. RESULTS: Forward hop task- Peak vGRF (normalized for body mass) with 0 mm, 12 mm, and 24 mm lifts were 2.613±0.498, 2.616±0.497 and 2.495±0.518% BW, respectively. Significant differences were noted between 0 and 24 mm lift (p<.001) and 12 and 24 mm lifts (p=.004), but not between the 0 and 12 mm conditions (p=.927). Jump-landing task- No significant differences were found in peak vGRF (p=.192) between any of the heel lift conditions. CONCLUSIONS: The addition of a 24 mm heel lift to the bottom of a sneaker significantly alters peak vGRF upon landing from a unilateral forward hop but not from a jumping maneuver.

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El objetivo de esta investigación es desarrollar una metodología para dimensionar un mecanismo policéntrico de rodilla de 4 barras para máxima estabilidad. Basado en el hecho de que la estabilidad del mecanismo durante la respuesta a la carga depende de la posición del centro instantáneo de rotación (CIR) respecto la fuerza de reacción del piso (FRP) durante la fase de apoyo, se desarrolló una plataforma de cómputo que representa el movimiento real de la pierna, el vector FRP y el mecanismo con su CIR. Para obtener los datos de entrada a la plataforma, se realizó un análisis de marcha a una paciente con amputación transfemoral unilateral, obteniendo la FRP, el ángulo de flexo-extensión de rodilla y la cinemática de los miembros inferiores. Por otra parte, a través de los algoritmos genéticos (AGs), se obtienen las dimensiones y configuración de los eslabones del mecanismo requeridas para iterar con la plataforma en la cual, comparando la ubicación de la FRP respecto al CIR en el plano sagital, se determinan las dimensiones funcionales adecuadas. El mecanismo se dimensionó exitosamente utilizando la metodología desarrollada, garantizando estabilidad de la rodilla después del contacto inicial y flexión voluntaria antes del despegue de punta.

This research was aimed to develop a methodology for establishing the proper dimensions of a four-bar linkage prosthetic knee mechanism for maximum stability. Based on the fact that the stability of a four-bar knee during load-bearing is determined by the location of the instantaneous center of rotation (ICR) with respect to the ground reaction force (GRF) vector, a computational platform was developed to simulate the movement of the leg, the GRF vector and the position of the ICR of the mechanism. On one hand, a gait analysis was carried out on a subject with unilateral transfemoral amputation, from which the GRF, the knee flexion-extension angle and the kinematics of the lower limbs were determined. On the other hand, genetic algorithms (GAs) technique provided the dimensions and mechanism links configuration required to iterate with the platform on which, comparing the location of the GRF and the ICR in the sagittal plane, the functional dimensions of the mechanism were obtained. The polycentric knee mechanism was gauged successfully by ensuring knee stability during the initial contact and load response as well as the ability to initiate voluntary flexion toward late stance before the toe-off.

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O objetivo do presente estudo foi investigar a contribuição dos parâmetros biomecânicos para o desempenho do salto vertical com contramovimento (SV) e SV precedido de corrida (SVcorrida) em 19 jogadoras da seleção brasileira adulta de basquetebol feminino (26,2 ± 4,7 anos; 1,81 ± 0,07 m; 75,6 ± 12,6 kg; 20,4 ± 6,0% de gordura). Foram considerados os picos de força passiva (PFPa) e propulsão (PFP), tempo para alcance dos picos de força passiva (TPFPa) e propulsão (TPFP), "load rate" (LR), taxa de desenvolvimento de força (TDF), tempo de fase excêntrica (Texc) e concêntrica (Tcon). A análise de componentes principais revelou que 50,86% da altura de SV foi explicada por PFPa, TPFPa, LR, Texc e TPFP, e que 43,28% de SVcorrida foi explicada por PFPa, TPFPa, LR, PFP. Esses resultados sugerem que parâmetros temporais parecem contribuir de maneira mais significativa para o desempenho de salto, porém diferentes tipos de salto podem demandar comportamentos distintos de parâmetros biomecânicos.

The aim of the study was to investigate the contribution of biomechanics parameters to counter-movement jump (CMJ) and CMJ preceded by run (CMJrun) in nineteen female basketball players from Brazilian National Team (26.2 ± 4.7 years; 1.81 ± 0.07 m; 75.6 ± 12.6 kg; 20.4 ± 6.0 % body fat). The parameters analyzed were passive (PaPF) and propulsion peak force (PPF), time to passive (TPaPF) and propulsion peak force (TPPF), load rate (LR), rate of force development (RFD), eccentric (Texc) and concentric phase duration (Texc). The principal component analysis showed that 50.86% of CMJ performance was explained by PaPF, TPaPF, LR, Texc and TPPF, and 43.28% of CMJrun was explained by PaPF, TPaPF, LR and PPF. These findings suggest that temporal parameters appear to have greater contribution to jump performance. Moreover, different types of jumps appear to induce distinct behavior of biomechanics parameters.

El objetivo de este estudio fue investigar la contribución de parámetros biomecánicos para el rendimiento de salto vertical con contra movimiento (SV) e SV precedido de carrera (SVcarrera) en diecinueve jugadoras de baloncesto de la selección brasileña femenina adultas (26,2 ± 4,7 años; 1,81 ± 0,07 m; 75,6 ± 12,6 kg; 20,4 ± 6,0% de grasa). Fueran considerados el pico de fuerza pasiva (PFPa) y propulsión (PFP), tiempo para llegar a picos de fuerza pasiva (TPFPa) y propulsión (TPFP), la tasa de carga (LR), tasa de desarrollo de fuerza (TDF), tiempo de la fase excéntrica (Texc) y concéntrica (Tcon). Las análisis de los componentes principales mostraron que 50,86% da la altura de SV fue explicada por PFPa, TPFPa, LR, Texc y TPFP, y que 43,28% de SVcarrera fue explicada por PFPa, TPFPa, LR, PFP. Los resultados sugieren parámetros temporales parecen contribuir más significativamente para rendimiento del salto pero, diferentes tipos del salto pueden demandar comportamientos distintos de los parámetros biomecánicos.

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A marcha é uma atividade da vida diária do homem, que, apesar de rotineiro, está longe de ser simples, constituindo um dos mais complexos e integrados movimentos realizados pelo ser humano. Este artigo, por meio de uma revisão de literatura, visou identificar os estudos relacionados com a componente vertical da força de reação do solo, durante a marcha humana, em diferentes públicos e ambientes/situações, a fim de amenizar ou até mesmo tentar evitar problemáticas relacionadas a lesões. Foram realizadas pesquisas em bases dedados e congressos da área de biomecânica sobre a marcha, força de reação do solo, velocidade, superfícies e cargas. Foram selecionados textos que identificassem estudos relacionados principalmente à força de reação vertical máxima em superfícies distintas, com diferentes calçados, assim como utilização de diversos meios para realização da marcha e em diferentes velocidades. A magnitude das forças aplicadas sobre o membro inferior durante a marcha é influenciada pela velocidade de execução, pelo incremento de cargas e também pelo tipo de calçado utilizado pelo indivíduo. O tipo de superfície e o ambiente são alternativas para diminuição do impacto. As atividades realizadas em ambiente aquático, devido à diminuição das cargas em relação ao ambiente terrestre, são propícias para a realização de exercícios. Estes resultados levam à conclusão de que a quantificação da força de reação do solo, imposta ao membro inferior durante a marcha é importante para criação de programas de exercícios físicos e terapias de reabilitação da marcha.

Gait is a human being’s daily life activity; however, despite of being customary, it is not simple. It is one of the most complex and integrated movements. This article, by means of literature review, aimed to identify studies related to the vertical component of theground reaction force during human gait for different publics and environments/situations in order to soften or even try to avoid injuryrelatedproblems. Researches on gait from databases and congresses on the gait biomechanics, ground reaction force, velocity, surfaces and loads were conducted. Texts on related studies mainly identifying the maximum vertical reaction force in different surfaces, with different shoes, as well as the use of varied gait ways with different velocities were selected. The magnitude of the forces applied over the lower limbs during gait is influenced by velocity of execution, rise of loads, and also the type of shoes. Type of surface and environment are alternatives for im pact reduction. Activities performed in aquatic environment – due to the decrease of the load in relation to the terrestrialenvironment – are favorable for the exercise performance. Results show that quantification of the vertical reaction force imposed to the lower limbs during the gait is important for the creation of physical exercises and therapies for gait rehabilitation.

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