Wyniki wyszukiwania - Biblioteka Nauki

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Body composition, power muscle, and baropodometric assessment in elite Muay Thai athletes

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Monterrosa Quintero A. , Fuentes-Garcia J. P. , Poblete-Valderrama F. , Pereira de Andrade G. A. , De la Rosa A.

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nr 3

12-22

EN

Background. Muay Thai is a dynamic fighting style which has existed for over 2000 years and consists of using a multitude of fists, kicks, and knee and elbow strikes to knock out the opponent. Studies indicate that the general physiologic profile of Muay Thai athletes is high anaerobic power and muscular strength, with low body fat percentage and a mesomorphic somatotype. Problem and Aim. Evaluate morphological, physical and baropodometric characteristics of elite male Muay Thai athletes. Methods. Fifteen elite Muay Thai athletes performed the following tests: Anthropometric measurement, lower limb muscle power and baropodometric assessment in static conditions. Results. Athletes presented body fat percentage (10.8 ± 3.8%) and balanced mesomorphic somatotype (2.3- 5.5-2.1). In lower limb strength performance, we observed measures of 44.7 ± 4.4 cm, 1640 ± 284 N, and 4.1 ± 3.6 % in vertical jump height, maximum force and bilateral asymmetry index percentage respectively. Additionally, baropodometric analysis revealed higher maximum force values in the heel and metatarsal zones (p<0.01 and p< 0.05, respectively). On the other hand, peak pressure and load distribution values were higher in the dominant foot (p<0.05). Moreover, we observed a higher load distribution percentage on the rearfoot surface than the forefoot surface in both the left (58.7% and 41.3%, respectively) and right foot (64.3% and 35.7% respectively). Conclusions. These results provided a profile of elite Muay Thai athletes that could be used as training and tactical targets for developing athletes.

PL

Tło. Muay Thai to dynamiczny styl walki, który istnieje od ponad 2000 lat i polega na użyciu pięści, kopnięć, uderzeń kolanami i łokciami w celu znokautowania przeciwnika. Badania wskazują, że ogólny profil fizjologiczny sportowców Muay Thai to wysoka moc beztlenowa i siła mięśni, z niskim procentem tkanki tłuszczowej i mezomorficznym somatotypem. Problem i cel. Ocena cech morfologicznych, fizycznych i baropodometrycznych elitarnych zawodników Muay Thai. Metody. U piętnastu elitarnych zawodników Muay Thai wykonano następujące testy: pomiar antropometryczny, siła mięśni kończyn dolnych i ocena baropodometryczna w warunkach statycznych. Wyniki. Sportowcy charakteryzowali się procentową zawartością tkanki tłuszczowej w organizmie (10,8 ± 3,8%) i zrównoważonym somatotypem mezomorficznym (2,3- 5,5-2,1). W zakresie siły kończyn dolnych zaobserwowano odpowiednio 44,7 ± 4,4 cm, 1640 ± 284 N i 4,1 ± 3,6% wysokości skoku pionowego, maksymalnej siły i dwustronnego wskaźnika asymetrii. Dodatkowo, analiza baropodometryczna wykazała wyższe wartości siły maksymalnej w strefie pięty i śródstopia (odpowiednio p<0,01 i p<0,05). Z drugiej strony, szczytowe wartości ciśnienia i rozkładu obciążenia były wyższe w stopie dominującej (p<0,05). Ponadto zaobserwowano wyższe obciążenie oraz większy procentowy rozkład obciążenia na powierzchni tylnej części stopy niż na powierzchni przedniej części stopy zarówno w lewej (odpowiednio 58,7% i 41,3%), jak i prawej stopie (odpowiednio 64,3% i 35,7%). Wnioski. Wyniki te dostarczyły profilu elitarnych sportowców Muay Thai, który można wykorzystać jako cele treningowe i taktyczne dla rozwijających się sportowców.

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Plantar pressure analysis of above-knee amputee with a developed microprocessor-controlled prosthetic knee

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Cao W. , Yu H. , Meng Q. , Li S.

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2018

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tom Vol. 20, no. 4

33--40

EN

Human gait motion analysis was one useful method for lower limb prosthesis study. The most often measured parameters were plantar pressure, kinetic and kinematic parameters. It was indispensable for prosthetic knee design and performance assessment. The aim of this study was to analysis the plantar pressure in traumatic above-knee amputee equipped with a developed microprocessor-controlled prosthetic knee. Methods: The maximum force of forefoot and rearfoot, the average vertical reaction force and pressure and the centre of pressure (COP) offset trajectories of ten above-knee amputees under different walking speeds were obtained. Results: Both forefoot and rearfoot force were bigger in intact leg than prosthetic leg. As the speed increased, the pressure increased in both sides. Forefoot bore more pressure than rearfoot in both legs. The average vertical pressure and force both increased along with the increase of speed. The force and pressure of intact side were always bigger than the prosthetic side. The trend of COP and gait line of the prosthetic and intact side had no significant difference. The length of the gait line of prosthetic side was greater than the intact side. Conclusions: The results of this study exhibited reduced plantar pressure in the prosthetic side. The typical butterfly diagrams were produced during different walking speeds. It indicated that the stability of the microprocessor-controlled prosthetic knee could be guaranteed.

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Development and testing of a wearable passive lower-limb support exoskeleton to support industrial workers

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Yan Z. , Han B. , Du Z. , Huang T. , Bai O. , Peng A.

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tom Vol. 41, no. 1

221--238

EN

A custom-designed, wearable, lightweight, and passive exoskeleton was proposed to provide gravity support for industrial workers to reduce prevalence of musculoskeletal disorders, joint injures, and arthritis caused by repeatedly or persistently squatting task. The designed exoskeleton can act as a wearable chair to allow workers to squat for an extended period when performing prolonged tasks. The exoskeleton employs torsion springs to store energy harvested from the squatting motion, and the stored energy is released to help the workers stand up. Dimensions optimization designs based on the finite element analysis program were implemented for a lightweight of the device. Besides, the exoskeleton effectiveness was investigated by performing an ergonomic assessmenton muscular activity, plantar pressure, endurance time, and comfort. The plantar pressure and electromyography of rectus femoris, biceps femoris, vastus medialis, and vastus laterals were measured in a simulated assembly task with the knee bend for three different angles (60°, 90°, 120°) under two conditions of with and without the exoskeleton. The endurance time was recorded in three different static squatting tasks. The comfort with the exoskeleton was recorded. Under the condition of wearing the exoskeleton, the average reduction of muscle activity was 44.8–71.5%, and the plantar pressure was 58.5–64.2%. The exoskeleton contributed to an increase in endurance time from 2.76 to 13.58 min. Moreover, 70% of the subjects exhibited a comprehensive exoskeleton comfort score of higher than 70. The experimental results demonstrated that this exoskeleton has good potential to reduce physical workload and increase endurance time during industrial assembly tasks.

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Analysis of foot load during ballet dancers’ gait

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Prochazkova M. , Tepla L. , Svoboda Z. , Janura M. , Cieslarová M.

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tom Vol. 16, no. 2

41--45

EN

Ballet is an art that puts extreme demands on the dancer’s musculoskeletal system and therefore significantly affects motor behavior of the dancers. The aim of our research was to compare plantar pressure distribution during stance phase of gait between a group of professional ballet dancers and non-dancers. Thirteen professional dancers (5 men, 8 women; mean age of 24.1 ± 3.8 years) and 13 nondancers (5 men, 8 women; mean age of 26.1 ± 5.3 years) participated in this study. Foot pressure analysis during gait was collected using a 2 m pressure plate. The participants were instructed to walk across the platform at a self-selected pace barefoot. Three gait cycles were necessary for the data analysis. The results revealed higher ( p < 0.05) pressure peaks in medial edge of forefoot during gait for dancers in comparison with nondancers. Furthermore, differences in total foot loading and foot loading duration of rearfoot was higher ( p < 0.05) in dancers as well. We can attribute these differences to long-term and intensive dancing exercises that can change the dancer’s gait stereotype.

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A real time plantar pressure feedback device for foot unloading

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Femery V. , Hespel J. M. , Thevenon A. , Moretto P.

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tom Vol. 6

IT103--106

EN

The design and development of a plantar pressure control device, adapted to correct plantar pressure distribution patterns, is described. This device is based on the artificial return of information in real time to instantaneously reveal to subject certain events, of which he was unaware and which are difficult to quantify, such as the pressure variation generated by foot-ground contact. An acoustic alarm and visual signals, adjusted to a specific pressure load, alert the user in the case of excessive plantar pressure. So, our feedback device is designed to substitute for loss of feeling in patients who have peripheral neuropathy secondary to diabetes mellitus. The ultimate aim of this project is to prevent the development of neuropathic foot ulceration by providing both visual and auditory extrinsic sensory feedback to compensate for the malfunctioning peripheral nerves and to transmit information to the patient about dangerous conditions on the plantar surface of the feet. A trial of the device in a healthy subject is presented to evaluate whether a new gait pattern can emerge thanks to feedback from plantar pressure measurements.

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Effects of unstable elements with different hardness on lower limb loading

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Li F. , Mei Q. , Gu Y.

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tom Vol. 17, no. 2

85--92

EN

Purpose: Osteoarthritis of the knee is one of the most common diseases. For this chronic disease, modified footwear structure can effectively prevent and relieve disease of the knee. The aim of this study was to explore the effects of shoe surface elastic modulus on external knee adduction moment and ground reaction force and foot loading characteristics. Methods: Sixteen healthy female volunteers were recruited, and each subject performed five walking trials under two shoes condition. The lower limb loading data was collected using force platform and in-sole pressure measurement system. Results: The results showed that the external knee adduction moment was decreased in all stance phase when wearing SS (unstable shoes with soft unstable elements), compared with HS (unstable shoes with hard unstable elements). The ground reaction force showed no obvious change under two shoes condition. Additionally, compared with HS, plantar pressure transferred from medial foot to lateral foot when wearing SS. Along with changes of contact areas, average pressure and impulse had also presented this tendency. Conclusions: These results can provide some scientific evidence and suggestions for footwear companies, and for the foot plantar medial injury disease has also certain applicability.

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Plantar pressure image fusion for comfort fusion in diabetes mellitus using an improved fuzzy hidden Markov model

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Li Z. , Wang D. , Dey N. , Ashour A. S. , Sherratt R. S. , Shi F.

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tom Vol. 39, no. 3

742--752

EN

Diabetes mellitus is a clinical syndrome caused by the interaction of genetic and environmental factors. The change of plantar pressure in diabetic patients is one of the important reasons for the occurrence of diabetic foot. The abnormal increase of plantar pressure is a predictor of the common occurrence of foot ulcers. The feature extraction of plantar pressure distribution will be beneficial to the design and manufacture of diabetic shoes that will be beneficial for early protection of diabetes mellitus patients. In this research, texture-based features of the angular second moment (ASM), moment of inertia (MI), inverse difference monument (IDM), and entropy (E) have been selected and fused by using the updown algorithm. The fused features are normalized to predict comfort plantar pressure imaging dataset using an improved fuzzy hidden Markov model (FHMM). In FHMM, type-I fuzzy set is proposed and fuzzy Baum–Welch algorithm is also applied to estimate the next features. The results are discussed, and by comparing with other back–forward algorithms and different fusion operations in FHMM. Improved HMMs with up–down fusion using type-I fuzzy definition performs high effectiveness in prediction comfort plantar pressure distribution in an image dataset with an accuracy of 82.2% and the research will be applied to the shoe-last personalized customization in the industry.