Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 19 de 19
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Front Physiol ; 14: 1198485, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37440998

RESUMO

Background: Little is known about changes in anthropometric and body composition (A&BC) characteristics during the aging process. Research indicates that body composition can be linked with socioeconomic status (SES), health status (HS), and physical activity (PA) levels. Aim: The aim of this study was to evaluate age-related changes in A&BC characteristics in female seniors aged 60+ in view of their SES, HS, and PA levels. Methods: The survey was conducted in November and December 2022 on a total of 661 female seniors. A questionnaire survey was conducted to obtain information about the participants' socioeconomic status (chronic diseases, health status, marital status, membership in social organizations, financial status, place of residence, education). The respondents' PA levels were assessed with the International Physical Activity Questionnaire (IPAQ), and their A&BC characteristics were determined in a bioelectrical impedance analysis with the InBody 270 body composition analyzer. The relationships between A&BC characteristics and age were evaluated based on the values of the Pearson correlation coefficient (r). Results: The mean values of Percent Body Fat (PBF), Body Mass Index (BMI), and the waist-hip ratio (WHR) were relatively high (37.2%, 28.5 kg/m2, and 0.8, respectively) and indicative of overweight and gynoid obesity. A higher number of significant negative correlations between A&BC characteristics and age were observed in seniors with lower values of SES, HS, and PA, which points to more rapid involutional changes in this group of respondents. A segmental analysis also revealed significantly lower values of fat-free mass (FFM) and body fat mass (BFM) (both indicators were calculated in percentage and kg), in particular in the upper limbs, in women with lower SES, HS, and PA levels. Conclusion: Environmental factors, including biological, physiological, environmental, psychological, behavioral, and social factors, are significantly associated with aging in women. Age-related changes in A&BC characteristics tend to proceed more rapidly in female seniors with low values of SES and HE and insufficient PA levels.

2.
Front Physiol ; 14: 1195641, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37334050

RESUMO

Background: Anthropometric and physiological characteristics are often considered as potential variables that are significantly related with motor performance. Aim: The aim of this study was to identify and weigh the key anthropometric and physiological characteristics that are associated with 2000-m rowing ergometer performance in male and female athletes. Methods: The study involved 70 best female and 130 best male rowers from the seven largest Hungarian rowing clubs, classified into one of the following age categories: juniors (36 women and 55 men, age range: 15-16 years), older juniors (26 women and 52 men, age range: 17-18 years), and seniors (8 women and 23 men, age range: over 18 years). Anthropometric and body composition measurements were determined by the bioelectrical impedance method proposed by Weiner and Lourie (1969), and skin fold measurements were conducted to estimate relative body fat content. The countermovement jump test and the 2000-m maximal rowing ergometer test were used for physiological measurements. Results: An increase in skeletal muscle mass was correlated (r = -.39, p <.001) with a significant decrease in rowing time over a distance of 2000 m, whereas a significant increase in rowing time was noted with an increase in sitting height (only in men, r = .33, p <.001), body mass (in women and men: r = .24, p = .013 and r = .31, p = .009), and body fat percentage (r = .26, p < .030). Rowing time was also bound by a significant correlation with maximal force (r = -.79 and -.90, p <.001) and relative maximal power (r = -.54 and -.78, p <.001) in both sexes, with relative peak power in males (r = -.51, p < .001), and with estimated relative maximal aerobic capacity in females (r = -.43, p <.001). Conclusion: Rowing performance over a distance of 2000 m is significantly negatively correlated with the skeletal muscle mass, maximal force, relative maximal power, relative peak power, and estimated relative maximal aerobic capacity.

3.
J Hum Kinet ; 86: 97-105, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37181266

RESUMO

Lower limb kinematics of the roundhouse kick is a well-known topic studied by many researchers. However, there is a lack of data about the velocity of the core and upper limbs during the execution of this technique. The aim of this study was to evaluate the differences in velocities of all crucial body segments while executing roundhouse kicks for both sides of the body. Thirteen elite taekwon-do athletes participated in this study. They performed kicks to a table tennis ball three times using each leg. The spatial-temporal data of markers placed on toes, knees, hips, shoulders, elbows, hands, and sternum were captured with the use of the Human Motion Lab equipment composed of 10 infrared cameras NIR Vicon MX-T40. There were statistical differences in the maximal velocity of the sternum and opposite shoulder. There were different correlations between the time of acquiring maximal velocities of specific body segments and the maximal velocity of the toe marker for each kicking side. Higher correlations were observed for the left kick despite the participant's declaration of their preference for the right leg. The obtained results facilitate the conclusion that small non-resistant targets require different motor control depending on the kicking side, despite not revealing significant differences between maximal velocity. While such an indicator could be perceived as a suitable benchmark of an athlete's performance, more detailed analysis seems to be required for a better understanding of martial arts techniques.

4.
Artigo em Inglês | MEDLINE | ID: mdl-36497735

RESUMO

This study aimed to examine the relation between the feeling of meaningfulness and also the characteristics of engaged participation (namely, the frequency of participation in voluntary groupings) and the level of anxiety among those who train a group of elite taekwon-do fighters. The research encompassed 58 people, all of whom were taekwon-do ITF (International Taekwon-do Federation) athletes at an elite level. The Questionnaire of Life Orientation (SOC-29) and the Inventory of the State and Features of Anxiety were used. The data were supplemented by the authors' own questions referring to activities in the field of taekwon-do. The group of taekwon-do fighters chosen was internally divided with regard to the level of the state of anxiety and the feeling of meaningfulness (p < 0.01). It was found that, together with the growth in the values stipulated in the accepted model, the frequency of taekwon-do groupings (ß = -0.38), as well as the feeling of meaningfulness (ß = -0.31), the value of the level of intensification of the state of anxiety dropped. The data revealed that, together with age, the level of anxiety decreased and the feeling of meaningfulness increased. The difference in the levels of anxiety between women and men was statistically non-significant (p > 0.05). The research findings illustrate that the feeling of meaningfulness and participation in groupings constitute a differentiating factor in terms of the intensification of the average level of anxiety in the elite taekwon-do group. More frequent participation in training goes hand-in-hand with the greater feeling of meaningfulness; perhaps, this is associated with the specific training, which, among other factors, favours adaptation to challenges and actions under pressure.


Assuntos
Senso de Coerência , Masculino , Humanos , Feminino , Inquéritos e Questionários , Ansiedade , Transtornos de Ansiedade , Emoções
5.
BMC Musculoskelet Disord ; 23(1): 948, 2022 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-36324093

RESUMO

INTRODUCTION: The three dimensional deformation of the spine in scoliosis is specific for a given child with regard to the number and length of curvatures, their degree of rotation and the size of the curvature angle. Early diagnosis of scoliosis in a clinical examination according to the Adams test depends on the correlation between the angle of trunk inclination (ATI) and the Cobb angle and the adopted diagnosis criterion. The aim of the study was to demonstrate the need to adopt different diagnostic criteria for ATI depending on the age and location of scoliosis. Moreover, the observed differences in the ATI/Cobb correlation became the basis for the proposal to introduce the concept of low, medium and high-rotated of curvature to the clinical description of scoliosis. MATERIALS AND METHODS: The group consisted of 229 children who were first examined, aged 6 to 17 years, with an average age of -11.57 years (SD ± 3.26), with symptoms of idiopathic scoliosis. The correlation of the criteria for the diagnosis of scoliosis in the ATI 7° clinical trial with a Cobb angle of 10° three dimensional in the X-ray image was used to distinguish three types of curvature/scoliosis, i.e., low, medium and high rotation. The frequencies of each type were compiled for three age groups and three scoliosis locations. Moreover, the degree of vertebral rotation according to the Perdriolli (AVR) of curvature was correlated with the Cobb angle and ATI. A one-way logistic regression model was used to assess the effectiveness of scoliosis detection in children based on the measurement of the ATI angle alone and the measurement of both ATI and Cobb angles. RESULTS: Low-rotated curves were most often found in the age groups of 6-9 and 10-12 years in 65.6% and 71.4% of patients, respectively (p < 0.05). Medium-rotated curvatures were most common in the age group of 13-17 years - 51.6%. With regard to the localization of scoliosis, the low-rotated curvatures were significantly more frequently (p < 0.05) found in the lumbar and thoracolumbar spine. Moreover, the univariate regression model for ATI showed that we could detect scoliosis best by taking the cut-off point of 5° and the mathematically determined Cobb angle was 9.5°. Patients with ATI ≥ 7° had significantly higher AVR values ​​than those with ATI < 7°, and the ATI/AVR correlation was of average strength. CONCLUSION: The specific morphology of the scoliotic curvature of the child's spine may be manifested by the difference in the ATI/Cobb correlation depending on the location of the scoliosis and change with age. The curvatures of the scoliosis that form can be low, medium and high-rotated, and the low-rotated curvatures were most often found in the 6-9- and 10-12-year-old groups and in the lumbar and thoracolumbar section. To increase the rate of early diagnosis of scoliosis, the results suggest the need to adopt two ATI criteria for the diagnosis of scoliosis at screening, 5° for age of 6-12 years, and when asymmetry affects the lumbar and thoracolumbar section, and 7° for the remaining children.


Assuntos
Escoliose , Adolescente , Criança , Humanos , Diagnóstico Precoce , Exame Físico , Rotação , Escoliose/complicações , Escoliose/diagnóstico por imagem , Coluna Vertebral/diagnóstico por imagem , Vértebras Torácicas/diagnóstico por imagem , Ensaios Clínicos como Assunto
6.
BMJ Open ; 12(9): e059658, 2022 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-36167364

RESUMO

OBJECTIVES: Yoga is an ancient form of physical activity (PA) that encompasses meditation, stretching and breathing techniques. Although the benefits of PA and associated lifestyle interventions are clear, we here addressed the paucity of evidence regarding the specific relationship between yoga and quality of life (QOL) in adults in Poland. We hypothesised that participation in PA and yoga could result in a positive impact on QOL. DESIGN: Cross-sectional, self-administered questionnaire-based survey. Both the quantitative and qualitative variables were statistically compared. Multivariate analyses were performed using linear regression. Results were determined based on age, sex and education level; a p<0.05 was considered significant. SETTING: Questionnaires were delivered to participants online, at high schools and universities, and in elderly communities in Poland. PARTICIPANTS: 714 polish citizens aged over 18 participated in the study; there are no specific entry and exclusion criteria besides age. RESULTS: Statistically significant differences (p<0.05) were observed between the QOL of the physically active group (PAG) and non-PAG (N-PAG). Meanwhile, yoga practice was revealed to have a significant effect on QOL; QOL was found to be statistically higher (p<0.001) in the PAG with yoga (PAG-Y) (4.29±0.66) than in the N-PAG (3.83±0.92) and PAG without yoga (4.07±0.68). CONCLUSIONS: The study shows that both regular PA and yoga practices could improve QOL; however, PAG-Y produced higher QOL scores than PA of other types. This outcome may be explained by the impact of physiological and psychological aspects within yoga practice. These results suggest that this unique combination impacts health more positively than other kinds of PA alone.


Assuntos
Meditação , Yoga , Adolescente , Adulto , Idoso , Estudos Transversais , Exercício Físico , Humanos , Polônia , Qualidade de Vida/psicologia
7.
Artigo em Inglês | MEDLINE | ID: mdl-35206204

RESUMO

Currently, there are pros and cons of research results related to weight cutting in combat sports, resulting in inconclusive results regarding the effects of weight-cut on athletes' performance, and biomechanical investigations are hardly seen. Therefore, this pilot study tried to fill the gap by initiating an exploration in real-life competitions. It is our hope to add biomechanical insights (advantages/disadvantages) that would discern the impact of weight cutting on competitive performance and help to structure hypotheses in future research. The method consisted of 3D motion capture, EMG measurement and biomechanical modeling. Through the synchronized data, striking power, striking accuracy and reaction time were quantitatively determined. Pre- and post-test design was used to test common strikes before weight cutting and 24 h after weigh-in. Seven male athletes from local clubs were tested during regional competitions. Results were characterized by using descriptive statistics (means and standard deviations) and T-tests were performed to contrast differences between the pre- and post-tests. This pilot study has revealed that there is actually weight-regain instead of weight-loss. The weight-regain would speed up the perceptional and total reaction, slow down the limbs' movement, worsen the striking accuracy and, possibly, decrease the strike power. The preliminary results are inconclusive regarding the competitive advantages/disadvantages induced by weight cutting. Further biomechanical studies are needed to deal with the controversial subject more objectively and scientifically.


Assuntos
Desempenho Atlético , Artes Marciais , Atletas , Humanos , Masculino , Projetos Piloto , Redução de Peso
8.
J Hum Kinet ; 80: 61-69, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34868417

RESUMO

The phenomena of target kinematic effects under different striking conditions and applying different techniques constitute one of the fields of research for sports biomechanics. However, the influence of some kinematic variables which change under different strike conditions for specific parts of the lower limb remains unknown. The aim of this study was to extend the knowledge on how targets of different shapes or the lack of a physical target would affect maximal velocity registered by a marker placed on the foot, knee and hip during the execution of a roundhouse kick. In total, 15 adult males were included in this study. All participants were taekwon-do elite athletes. The displacement of markers placed on the lateral side of the foot, knee and hip during movement execution was registered by a stereophotogrammetry apparatus. Participants performed taekwon-do roundhouse kicks for three target types (into the air, a table tennis ball and a training shield) applying either a sport or a traditional style. The highest maximal velocity was obtained for kicking into the training shield. When applying the sport style, the highest maximal velocity of foot markers for the executed kicks was registered. Kicking into air resulted in higher velocities for proximal body parts than kicking into a tennis ball, but the effect was reversed for the foot marker. In conclusion, a large resistance target is suitable for athletes' motor preparation as it allows the highest maximum velocity to be reached. Small non-resistant targets are recommended for technical training.

9.
Artigo em Inglês | MEDLINE | ID: mdl-34770018

RESUMO

The aim of this study was to determine the effects of thermal stress (TS) on changes in blood biochemical parameters and fluid electrolyte levels in young adult men with moderate and high levels of physical activity. Thirty men (22.67 ± 2.02 years) were exposed to four 12-min sauna sessions (temperature: 90-91 °C; relative humidity: 14-16%) with four 6-min cool-down breaks. The evaluated variables were anthropometric, physiological, and hematological characteristics. The mean values of HRavg (102.5 bpm) were within the easy effort range, whereas HRpeak (143.3 bpm) values were within the very difficult effort range. A significant increase was noted in pO2 (p < 0.001), total cholesterol (p < 0.008), HDL (p < 0.006) and LDL cholesterol (p < 0.007). Significant decreases were observed in the SBP (by 9.7 mmHg), DBP (by 6.9 mmHg) (p < 0.001), pH (p < 0.001), aHCO3- (p < 0.005), sHCO3- (p < 0.003), BE (ecf) (p < 0.022), BE (B), ctCO2 (for both p < 0.005), glucose (p < 0.001), and LA (p < 0.036). High 72-min TS did not induce significant changes in the physiological parameters of young and physically active men who regularly use the sauna, excluding significant loss of body mass. We can assume that relatively long sauna sessions do not disturb homeostasis and are safe for the health of properly prepared males.


Assuntos
Banho a Vapor , Antropometria , Temperatura Corporal , Exercício Físico , Humanos , Masculino , Banho a Vapor/efeitos adversos , Temperatura , Adulto Jovem
10.
Artigo em Inglês | MEDLINE | ID: mdl-34444534

RESUMO

The COVID-19 pandemic is a public health emergency concern and a challenge to students' mental health due to changes in education and social isolation. The aim of this research was to expand knowledge about the relations that shape the level of anxiety amongst men and women who are studying during the pandemic in terms of the relations towards their sense of social support and their nutritional behaviors. A State-Trait Anxiety Inventory was used to measure anxiety level, alongside supplementary questions such as the feeling of support from close ones, concentration of attention on nutrition during the pandemic and externally derived factors (university, specialization). Analysis of the regression was applied to the examination of the dependency between the anxiety level (in both forms of its occurrence-as state-anxiety and as trait-anxiety). We observed that the pandemic situation affected a level of state-anxiety above average (mean value of 46-48 points) even when students felt social support. Nutrition habits and chosen education type are associated with trait-anxiety level, which was also elevated (mean values of 49-50 points). Chosen factors had a partial influence on the anxiety level of students, therefore their mental health should concern shaping positive nutrition habits and social support.


Assuntos
COVID-19 , Pandemias , Ansiedade/epidemiologia , Comportamento Alimentar , Feminino , Humanos , Masculino , SARS-CoV-2 , Apoio Social , Estudantes
11.
Acta Bioeng Biomech ; 23(4): 117-125, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-37341125

RESUMO

PURPOSE: The development of a motion capture system leads to fast and accessible ways of precise testing of athletes and their motor abilities. The striking performance in martial arts and combat sports requires measuring velocity in the context of successful contact with the target. The aim of this study was to present the novel kinematic target effect coefficient and its possible use as a speed accuracy benchmark of performance based on the example of taekwon-do roundhouse and frontal kicks. METHODS: The stereophotogrammetry motion capture setup consists of 10 infrared cameras (NIR Vicon MX-T40). Analysis includes 180 kicks (roundhouse and frontal kicks) performed by 15 adult participants on a master level in taekwon-do. The kinematic target effect comparison includes two targets - a training shield and a table tennis ball hanging from the ceiling. Markers were placed on the lower extremities of participants. Spatial-temporal variables were registered for both kicking legs, techniques, and target types. RESULTS: Both roundhouse and frontal kicks revealed target and marker dependent differences during its execution. The kinematic target effect coefficient values differ for the specific marker and kick type. CONCLUSION: The wireless motion capture systems could be helpful in the training process and an athlete's evaluation before sports competitions.

12.
PLoS One ; 15(10): e0239749, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33027278

RESUMO

BACKGROUND: Anxiety could be felt even in objectively peaceful situations, but a vision of conflict could result in increased stress levels. In this article, we aimed to identify hidden patterns of mental conditions and create male profiles to illustrate the different subgroups as well as determinants of anxiety levels among them in accordance with proximity to a possibility of direct exposure to military action. METHODS: A sample of Ukrainian males, in duty as conscripts to military service (n = 392, M±SD = 22.1±5.3) participated in a survey. We used the 36-Item Short Form Health Survey, and State-Trait Anxiety Inventory. In addition to psychological indices, social-demographic data were collected. To discover the number of clusters, the k-means algorithm was used, the optimal number of clusters was found by the elbow algorithm. For validation of the model and its use for further prediction, the random forest machine-learning algorithm, was used. RESULTS: By performing k-means cluster analyses, 3 subgroups were identified. High values of psychological indices dominated in Subgroup 2, while lowest values dominated in Subgroup 3. Subgroup 1 showed a more even distribution among the indices. The strength of the relevance and main determinants of the prediction of the presented model mostly consisted of mental qualities, while socio-demographic data were slightly significant. CONCLUSIONS: There is no clear relevance between proximity or even the experience of military actions and anxiety levels. Other factors, mostly subjective feelings about mental conditions, are crucial determinants of feeling anxiety.


Assuntos
Transtornos de Ansiedade/psicologia , Ansiedade/psicologia , Militares/psicologia , Adulto , Alcaloides de Berberina , Depressão/psicologia , Humanos , Aprendizado de Máquina , Masculino , Saúde Mental , Fenantridinas , Adulto Jovem
13.
Acta Bioeng Biomech ; 20(2): 133-138, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30220721

RESUMO

PURPOSE: The current study aimed to quantify the main influences and the interactions (joint effects) of gender, leg and type of target on the biomechanics of front kick quality. Through the quantification, we tried to identify the relevant factors related to the kick accuracy and maximum velocity for coaching practice. METHODS: A ten-camera NIR VICON MX40 motion capture system (250 Hz) was used to determine the kicking foot maximum velocity from two well-trained subject groups (8 males and 6 females). Each subject performed both left and right front kicks in a lateral standing position into the air (without a physical target), to a board, to a table tennis ball and to a training shield. The target were set on a height corresponding to a height of solar plexus of each participant. RESULTS: The results showed that all the three factors (gender, leg and type of target) have significant influences on kicking speed ( p < 0.001) and significant interaction (joint effect) was only found between gender and target ( p < 0.001). Further analysis revealed that the males' kicking maximum velocity was affected more by board, while females' one was affected by the size of the target. CONCLUSIONS: The results would seem to suggest that, for males, kick-to-a-board may be the more effective method for increasing kick quality, compared to other type of target. For females, kick-to-a-small-ball appears to be effective method for increasing kick maximum velocity.


Assuntos
Extremidade Inferior/fisiologia , Artes Marciais/fisiologia , Atividade Motora/fisiologia , Caracteres Sexuais , Fenômenos Biomecânicos , Análise Fatorial , Feminino , Humanos , Masculino , Adulto Jovem
14.
Ann Agric Environ Med ; 25(1): 172-175, 2018 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-29575855

RESUMO

INTRODUCTION: Military actions and injuries sustained make returning to ordinary life and everyday routine a challenge which soldiers need to face. Research on this subject shows that the consequences of post-traumatic stress extends further, beyond the victim's everyday life, resulting in health problems and problems with social relationships. OBJECTIVE: The aim was to gather knowledge of the ways of expressing anger in a group of hospitalized Ukrainian post-deployed servicemen. A research study was conducted concentrating on the two forms of managing anger, i.e. releasing or suppressing anger, and posing the following question: 'How are they manifested in the hospitalized Ukrainian combat veterans? MATERIALS AND METHOD: The study included 35 hospitalized soldiers who had taken part in military operations in Ukraine (age: 34.61±9.23; age range: 21-56 years of age). The research was conducted in the hospitals in Lutsk. Measurements were conducted with the use of certified psychological tests, i.e. Anger Expression Scale (AES), medical documentation and oral reports given by the persons conducting the study. RESULTS: The average value of the suppressed anger indicator was 31.57±6.23 (p<0.05); respective value of the released anger 24.37 ±6.34 (p<0.05). For released anger, results at the level of the upper quartile (Q3=28) and above were obtained by 28.57 % of the soldiers in the study, while in the case of repressed anger, the results obtained at the level of the upper quartile (Q3 = 36) and above that value were obtained by 34.27% of the soldiers/patients. CONCLUSIONS: The results obtained show that in the group of hospitalized patients/soldiers there is a higher level of repressed anger intensity than in the case of released anger. The study survey suggests that in their case expressing anger is usually a reaction to somebody's inappropriate-in-their-eyes behaviour. Curbing anger takes on various forms, from trying not to express annoyance and/or rage, to trying to keep calm in spite of growing anger caused by other people's behaviours.


Assuntos
Militares/psicologia , Transtornos de Estresse Pós-Traumáticos/psicologia , Adulto , Ira , Feminino , Hospitalização , Humanos , Masculino , Pessoa de Meia-Idade , Transtornos de Estresse Pós-Traumáticos/terapia , Ucrânia , Adulto Jovem
15.
Acta Bioeng Biomech ; 17(4): 115-20, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26898602

RESUMO

Taekwondo is famous for its powerful kicking techniques and the roundhouse kick is the most frequently used one. In earlier literature, the influence of a physical target (exiting or not) on kicking power generation has not been given much attention. Therefore, the aim of this study was to investigate the kinematics of roundhouse kick execution and its factors related to power generation. 6 ITF taekwondo practitioners voluntarily participated in this study. They were asked to perform kicks with and without a physical target. The first kick aimed at breaking a board while the second one was a kick into the air. A Smart-D motion capture system (BTS S.p.A., Italy) was used to quantitatively determine their kinematic characteristics during each kick. The main findings showed that kicks aiming at a breaking board were significantly slower than kicks without a physical target (maximal kick-foot velocities were 10.61 ± 0.86 m/s and 14.61 ± 0.67 m/s, respectively, p < 0.01), but the kicking time of the former was shorter (0.58 ± 0.01 s and 0.67 ± 0.01, respectively, p < 0.01). The results suggest that a physical target will negatively influence the kick-foot velocity, which is not necessarily a disadvantage for creating a high quality kick. Possible motor control mechanisms are discussed for the phenomenon. The study made it clear: trainings with and without physical targets would develop different motor control patterns. More studies are needed for identifying the effectiveness of different controls and efficiencies of their training.


Assuntos
Desempenho Atlético/fisiologia , Artes Marciais/fisiologia , Adolescente , Fenômenos Biomecânicos , Criança , Feminino , Pé/fisiologia , Humanos , Joelho/fisiologia , Masculino , Força Muscular/fisiologia , Músculo Esquelético/fisiologia , Adulto Jovem
16.
J Hum Kinet ; 30: 13-20, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23486086

RESUMO

The aim of the paper is to present an analysis of the influence of selected kinematic factors on the side kick technique. This issue is especially important in the traditional version of taekwon-do, in which a single strike may reveal the winner. Six taekwon-do (International Taekwon-do Federation) athletes were asked to participate in this case study. Generally accepted criteria of sports technique biomechanical analysis were adhered to. The athletes executed a side kick three times (in Taekwon-do terminology referred to as yop chagi) in a way which they use the kick in board breaking. The obtained data were used to determine the mean velocity changes in the function of relative extension length of the kicking leg. The maximum knee and foot velocities in the Cartesian coordinate system were determined. The leg lifting time and the duration of kick execution as well as the maximum force which the standing foot exerted on the ground were also determined. On the basis of the obtained values, mean values and standard deviations were calculated. The correlation dependence (r=0.72) shows that greater knee velocity affects the velocity which the foot develops as well as the fact that the total time of kick execution depends on the velocity which the knee (r = -0.59) and the foot (r = - 0.86) develop in the leg lifting phase. The average maximum speed was obtained at the length of the leg equal to 82% of the maximum length of the fully extended leg. This length can be considered the optimum value for achieving the maximum dynamics of the kick.

17.
Acta Bioeng Biomech ; 13(4): 71-5, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22339376

RESUMO

The aim of the paper is to present the analysis of the influence of chosen kinetic factors on the side-kick technique. This issue is of a significant importance in the traditional version of Taekwon-do, where a single strike may reveal the winner. A male athlete, a black-belt holder, has participated in this case study. Generally accepted criteria of sports technique biomechanical analysis were adhered to. The athlete executed a side kick four times (in Taekwon-do terminology referred to as yop chagi) in a way most typical of his usual kick execution in board breaking. The parameter values obtained were used to determine the individual curves of the changes in velocities in the function of relative extension length of the kicking leg. The maximum knee and foot velocities in the Cartesian coordinate system were determined. The leg lifting time and the total time of kick execution as well as the maximum force which the foot exerted on the ground were also determined. On the basis of the values obtained the average values and the standard deviation were calculated. The correlation dependence (r = 0.97) shows that a higher knee velocity significantly affects the velocity which the foot develops and that the total time of kick execution depends on the velocity which the knee develops in the leg lifting phase (r = 0.75). The average maximum speed was obtained at the length of the leg equal to 82% of the maximum length of the fully extended leg. In the kicking technique used by the athlete, this length can be considered for this athlete the optimum value for achieving the maximum strike dynamics.


Assuntos
Artes Marciais/fisiologia , Movimento/fisiologia , Adolescente , Fenômenos Biomecânicos/fisiologia , Pé/fisiologia , Humanos , Articulações/fisiologia , Joelho/fisiologia , Perna (Membro)/fisiologia , Masculino , Postura/fisiologia , Fatores de Tempo
18.
Polim Med ; 33(3): 39-52, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-14696524

RESUMO

The results of experiment of diffusive transmembrane transport in a single-membrane osmotic-diffusive electrochemical cell were presented. In all experiments one of the vessels was filed with pure water, and the second one--with aqueous potassium chloride solution in aqueous ammonia solutions of constant concentration. The flux of potassium chloride was assigned according to the following measure procedure. In a first step we assigned the time dependence of potassium chloride flux in conditions of uniform mechanically stirred solution with speed of 500 rpm. In a second step those characteristics were assigned in conditions of mechanically unstirred solution. Each experiment was made for two configurations of gravitational membrane system: (i) with the water in a vessel above the membrane and solution below it (configuration A) (ii) with the solution in a vessel above the membrane and water below it (configuration B). Taking under the consideration the values of potassium chloride flux in steady state for different solution concentration of the same substances and the same configurations of membrane system, the dependencies of potassium chloride flux from the solution concentration differences were made appropriately. On the base of those experiments the solute flux concentration boundary layers effects (jCBLE) were counted. Moreover it was shown that single-membrane osmotic-diffusive electrochemical cell has rectifier and amplifying of diffusive flow features. The coefficients, appropriately, of asymmetry and amplification of diffusive flux are the measurements of those features.


Assuntos
Transporte Biológico , Membranas Artificiais , Polímeros , Amônia/farmacocinética , Difusão , Cloreto de Potássio/farmacocinética
19.
Acta Dermatovenerol Croat ; 11(4): 212-6, 2003 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-14670220

RESUMO

Cutaneous leiomyomas are rare, benign tumors arising from the arrectores pilorum muscles of the skin, the tunica dartos of the scrotum, muscles of the areola of the nipple, and vulvar or vascular smooth muscles. Multiple cutaneous leiomyomas originate from the arrectores pilorum muscles of the skin (piloleiomyomata cutis). Occasionally, they seem hereditary and may be associated with uterine myomas. We present a family in which the mother and 4 of her 6 daughters had uterine myomas. All sisters had to undergo hysterectomy before the age of 40, and three of them had multiple cutaneous leiomyomas simultaneously. Our observations support the suggestion that this kind of leiomyomas is a disorder with autosomal dominant inheritance with incomplete gene penetration. Moreover, the data indicate the necessity of periodical examinations to rule out the presence of uterine myomas not only in cutaneous leiomyoma patients, but also in other women in a given family.


Assuntos
Leiomioma/genética , Segunda Neoplasia Primária/genética , Neoplasias Cutâneas/genética , Neoplasias Uterinas/genética , Feminino , Humanos , Leiomioma/patologia , Pessoa de Meia-Idade , Segunda Neoplasia Primária/patologia , Linhagem , Neoplasias Cutâneas/patologia , Neoplasias Uterinas/patologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...