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1.
Undersea Hyperb Med ; 48(1): 81-88, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33648037

RESUMO

The snorkel allows a surface swimmer to observe the underwater world through the face mask without being disturbed by inhaling. The effect of a snorkel on breathing resistance and cost is widely held to be substantial. This study aims to model these parameters and to measure indirectly the actual increases. Further, resistances of differing designs and dimensions were assessed and recommendations were made concerning use and choice. Maximal voluntary ventilation in 12 seconds (MVV12) was measured in 19 volunteers seated on dry land with and without a classic J-type snorkel (inner diameter 20.5 mm). The extra and total resistances and costs were calculated using the MVV12 data and using estimated airways resistance extrapolated from subject's demography and spirometric literature data. MVV12 measurements with snorkel showed a minute volume of 152 ±38 L∙min-1, 6.0 ±3.7% lower than without snorkel (p = 7.0x10-6). The theoretical MVV12, calculated from snorkel and airways resistances, decreased by 3.2%. Experimental total breathing resistance (457±83 Pa∙s∙L-1) was 6.5 ± 3.2% higher than without snorkel (p = 2.6x10-7), but the total mechanical breathing cost was unaffected by the snorkel (13.58 Watts with; 13.64 Watts without). Divers' estimations of resistance increase were exaggerated (8.8% at rest, 23% swimming). Classical J-type snorkels with an inner diameter ≥19.5 mm add 3-16% resistance . There is no risk of hypercapnia. Scuba divers are recommended to use their snorkel to breathe more comfortably on the surface. It is recommended the snorkel be made a mandatory safety accessory. The best multipurpose snorkel (19-21 mm) has no top appendages and no water release valve.


Assuntos
Resistência das Vias Respiratórias/fisiologia , Mergulho/fisiologia , Respiração , Equipamentos Esportivos , Natação/fisiologia , Algoritmos , Desenho de Equipamento , Humanos , Hipercapnia/etiologia , Mecânica Respiratória/fisiologia , Equipamentos Esportivos/efeitos adversos
2.
Public Health ; 190: 16-22, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33326889

RESUMO

OBJECTIVE: To examine the prevalence, and the demographic, socio-economic, and health correlates to Outdoor Gyms (OGs) use for adults from a southern Brazilian city. STUDY DESIGN: Population-based cross-sectional study. METHODS: A total of 431 adults (66.8% women) aged 18-87 years living in the surroundings of four OGs distributed in different regions of the city were randomly selected. Information about OG use for physical activity (PA) practice, and demographic, socio-economic, and health variables were collected by household interviews. Associations between independent variables and OG use were analyzed with results expressed as odds ratio (OR) and 95% confidence interval (95% CI). RESULTS: About one-third of participants (30.4%; 95% CI: 26.1-34.7) informed using OGs for PA practice, and 20.4% (95% CI 16.8-24.4) informed using it twice or more times a week (≥2x/week). Adjusted analysis indicated that the OG use ≥2x/week is higher for women (OR: 1.93; 95% CI: 1.11-3.35) and for those with lower family income (OR: 2.13; 95% CI: 1.03-4.13) than men and those with higher family income, respectively. CONCLUSION: About 30% of the population uses OGs for PA practice. Women and low-income people are those who more commonly use OGs for PA practice. The installation of these facilities in public spaces may reduce social inequities related to leisure-time PA.


Assuntos
Exercício Físico , Academias de Ginástica/estatística & dados numéricos , Pobreza , Características de Residência , Equipamentos Esportivos/estatística & dados numéricos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Brasil , Cidades , Estudos Transversais , Planejamento Ambiental , Características da Família , Feminino , Humanos , Entrevistas como Assunto , Masculino , Pessoa de Meia-Idade , Atividade Motora , Vigilância da População , Prevalência , Fatores Socioeconômicos , Adulto Jovem
3.
Clin Sports Med ; 40(1): 159-171, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33187606

RESUMO

Concussion remains a common injury among sports participants. Implementing risk-reduction strategies for sport-related concussion (SRC) should be a priority of medical professionals involved in the care of athletes. Over the past few decades, a multifaceted approach to reducing SRC risk has been developed. Protective equipment, rule and policy change/enforcement, educational programs, behavioral modifications, legislation, physiologic modifications, and sport culture change are a few of the programs implemented to mitigate SRC risk. In this article, the authors critically review current SRC risk-reduction strategies and offer insight into future directions of injury prevention for SRC.


Assuntos
Traumatismos em Atletas/prevenção & controle , Concussão Encefálica/prevenção & controle , Educação em Saúde , Humanos , Cultura Organizacional , Equipamentos de Proteção , Política Pública , Fatores de Risco , Esportes/legislação & jurisprudência , Equipamentos Esportivos , Medicina Esportiva/organização & administração
4.
Rev. int. med. cienc. act. fis. deporte ; 20(79): 435-451, sept. 2020. graf, tab
Artigo em Espanhol | IBECS | ID: ibc-197047

RESUMO

Esta investigación plantea como objetivo principal diseñar un instrumento de registro que permita describir y relacionar tres niveles de acción del balonmano (juego de equipo, juego grupal y juego individual), vinculándolos al contexto de competición y atendiendo a su eficacia. Siguiendo las directrices de la metodología observacional se opta por un sistema combinado de formatos de campo y sistema de categorías, utilizando un diseño de investigación de carácter ideográfico, puntual y multidimensional. Se utiliza como instrumento de registro el software Dartfish TeamPro V.4.5 para analizar siete partidos de categoría absoluta, y siete partidos de categoría infantil, generándose datos de tipo concurrente y de evento. Se aplican técnicas estadísticas descriptivas e inferenciales bivariadas para el análisis relacional de los datos. Destacamos los resultados que constatan la asociación entre sistemas de juego y procedimientos colectivos tanto ofensivos como defensivos, y la dificultad en establecer relaciones significativas entre el ataque y la defensa


The main aim of this research was to design a recording tool that allows describing and relating three levels of action in team handball (team play, group play and individual play), linking them to the competition context and taking their effectiveness into account. Following the guidelines of observational methodology, we selected a combined system of field formats and system of categories, using an ideographic, specific and multidimensional research design. Dartfish TeamPro V.4.5 software, was used as a recording instrument to analyse seven matches in the top category, and seven matches in the children's category, generating concurrent and event data. Bivariate descriptive and inferential statistical techniques were used for the relational analysis of the data. The results confirmed the association between game systems and collective procedures, both offensive and defensive, as well as the difficulty to establish significant relationships between attack and defense


Assuntos
Humanos , Masculino , Adolescente , Atletas , Esportes/fisiologia , Treinamento de Resistência/métodos , Equipamentos Esportivos/normas , Eficácia , Desempenho Físico Funcional , Análise de Variância , Esportes/normas
5.
J Orthop Sports Phys Ther ; 50(8): 415-417, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32736496

RESUMO

SYNOPSIS: Repeated purposeful heading in soccer has come under increased scrutiny as concerns surrounding the association with long-term neurodegenerative disorders in retired players continue to grow. Although a causal link between heading and brain health has not been established, the "precautionary principle" supports the notion that soccer governing bodies and associations should consider implementing pragmatic strategies that can reduce head impact during purposeful heading in youth soccer while this relationship is being investigated. This Viewpoint discusses the current evidence to support low-risk head impact reduction strategies during purposeful heading to protect young, developing players, and how such strategies could be implemented now while research and debate continue on this topic. J Orthop Sports Phys Ther 2020;50(8):415-417. doi:10.2519/jospt.2020.0608.


Assuntos
Cabeça/fisiologia , Destreza Motora/fisiologia , Futebol/fisiologia , Adolescente , Fatores Etários , Criança , Comportamento Competitivo/fisiologia , Feminino , Humanos , Masculino , Força Muscular , Músculos do Pescoço/fisiologia , Doenças Neurodegenerativas/prevenção & controle , Condicionamento Físico Humano/fisiologia , Fatores de Risco , Futebol/lesões , Equipamentos Esportivos
6.
Sports Health ; 12(5): 495-500, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32720852

RESUMO

BACKGROUND: Traditional exercises performed with the shoulder in the position of 90° abduction and external rotation with elbow flexion (90/90) while using a single elastic band showed moderate activity of both the lower trapezius (LT) and infraspinatus (IS) muscle. The purpose of this study was to investigate activity of the teres minor (TMi) and the LT muscles during standing external rotation exercise with the shoulder in the 90/90 position with 2 elastic bands in both the frontal and the scapular plane. HYPOTHESIS: TMi, IS, and LT muscle activities will vary depending on whether the shoulder is positioned in the frontal or scapular plane with the application of 2 elastic bands. Also, the serratus anterior (SA) and teres major (TMa) muscles will produce different muscular activity patterns during exercises performed with 2 elastic bands in the frontal plane compared with the TMi and LT muscles. STUDY DESIGN: Controlled laboratory study. LEVEL OF EVIDENCE: Level 4. METHODS: A total of 21 collegiate baseball players volunteered to participate. The electromyography (EMG) activities of the TMi, IS, LT, SA, TMa, middle deltoid (MD), posterior deltoid, and upper trapezius (UT) muscles were measured with the 90/90 arm position during both isometric and oscillation resistance exercises with 2 elastic bands oriented in the frontal and scapular planes. RESULTS: A significant difference was observed in EMG activity of both the TMi and the LT muscles between single and double elastic band applications in the frontal plane (P < 0.05). In contrast, EMG activity of the IS, SA, and TMa muscles was significantly increased in the scapular plane compared with the frontal plane (P < 0.05). CONCLUSION: The standing 90/90 position effectively increased both TMi and LT muscle EMG activity with the double elastic band in the frontal plane while minimizing UT and MD muscle activity. EMG activity of the IS, SA, and TMa muscles increased with exercise in the scapular plane as compared with the frontal plane. CLINICAL RELEVANCE: Oscillation movement under double elastic band application differentiated external rotator muscle and scapular muscle activities between the frontal and scapular plane during the 90/90 exercise in the frontal plane compared with the scapular plane. Clinicians can utilize each of the scapular and frontal positions based on their desired focus for muscular activation.


Assuntos
Braço/fisiologia , Beisebol/fisiologia , Treinamento de Resistência/instrumentação , Treinamento de Resistência/métodos , Manguito Rotador/fisiologia , Equipamentos Esportivos , Músculos Superficiais do Dorso/fisiologia , Eletromiografia , Humanos , Rotação
7.
J Sports Sci ; 38(21): 2415-2422, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32605426

RESUMO

Equipment scaling has yielded better performance in children in comparison to using adult equipment. To better inform applied practice in junior sport, an investigation of additional equipment modifications designed to further simplify the task is required. This study, therefore, aims to determine the effect of increasing surface area of cricket equipment (bats and balls) on batting performance and technique. Forty-three children (M age = 5.2, SD = 0.8 years) completed a cricket batting task in which they aimed to hit the ball through a target zone while using either regular-scaled, or modified bat and ball with an increased surface area. The number of bat-ball contacts was significantly higher when using the modified (M = 13.81, SE = 0.42) compared to the regular-scaled ball (M = 10.65, SE = 0.49). Batting performance measured as shots played through target areas was also significantly higher when using the modified (M = 31.78, SE = 1.97) than the regular-scaled ball (M = 28.85, SE = 2.27). More desirable technique was also observed when using the modified compared to the regular bat. Findings suggest that further modifications to regular-scaled equipment can enhance skill production.


Assuntos
Desempenho Atlético/fisiologia , Críquete/fisiologia , Desenho de Equipamento , Destreza Motora/fisiologia , Equipamentos Esportivos , Aceleração , Criança , Pré-Escolar , Feminino , Humanos , Masculino
9.
J Sports Sci ; 38(21): 2437-2445, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32608346

RESUMO

This study examined whether modulation of the centre of pressure (COP) on the starting block surface would improve sprint start performance. Twenty male national-level sprinters performed 15-m sprints from the starting blocks in three different conditions (normal, anterior loading and posterior loading), during which ground reaction forces (GRFs) were recorded. The COP location, 10-m time, average horizontal external power (AHEP), spatiotemporal and GRF variables were calculated. The results demonstrate that, although modulation of COP location may not improve sprint start performance for the entire group, it could improve the corresponding performance for specific individuals. A sprinter who favours the posterior front block location and more to the posterior rear block COP location on the block surface at the set position could possibly improve AHEP using the anterior loading condition. An improvement of AHEP in the anterior loading condition (p =.056, effect size [ES] =.305) would be accomplished by greater rear block anteroposterior mean force (p =.043, ES =.574). Moreover, the posterior loading condition may improve the 10-m time and/or AHEP for some individuals, whereas no specific characteristics of the individuals were found. Finally, an improvement of 10-m time in the posterior loading condition (p =.015, ES =.609) would be accomplished by shorter reaction time (p =.035, ES =.780).


Assuntos
Desempenho Atlético/fisiologia , Pé/fisiologia , Corrida/fisiologia , Suporte de Carga , Aceleração , Fenômenos Biomecânicos , Humanos , Masculino , Tempo de Reação , Equipamentos Esportivos , Adulto Jovem
10.
J Sports Sci ; 38(20): 2382-2389, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32600126

RESUMO

Elliptical trainers that increase the inter-pedal distance may have potential benefits for knee osteoarthritis by decreasing the amount of knee varus. Modifying elliptical trainers with a converging footpath and reduced inter-pedal distance may be beneficial for reducing anterior knee pathology risk by decreasing knee valgus angles. Twenty-one college students participated in a single testing session. Participants exercised on two different elliptical trainers, one modified with a converging footpath and reduced inter-pedal width, and a standard elliptical trainer. Participants exercised for 2 min at three ramps incline at 120 strides per minute and constant work rate. Three-dimensional kinematics and electromyography of the dominant lower limb were recorded. Multiple 2 × 3 (Elliptical x Incline) ANOVAs with Bonferroni corrections were used to compare the two elliptical trainers at each incline for kinematics and muscle activity. The modified elliptical trainer displayed significantly decreased peak knee valgus (p = 0.031, η p 2 = 0.234 ), peak knee flexion (p = 0.006, η p 2 = 0.246 ), and interactions for peak knee flexion (p = 0.001, η p 2 = 0.250 ) and vastus lateralis (p < 0.01, η p 2 = 0.380 ) muscle activity compared to the standard elliptical trainer. The decreased peak knee valgus and flexion angles could be beneficial for reducing long-term injury risk for anterior knee pathologies.


Assuntos
Extremidade Inferior/fisiologia , Músculo Esquelético/fisiologia , Equipamentos Esportivos , Fenômenos Biomecânicos , Eletromiografia , Desenho de Equipamento , Feminino , Marcha/fisiologia , Quadril/fisiologia , Humanos , Joelho/fisiologia , Masculino , Estudos de Tempo e Movimento , Adulto Jovem
11.
J Sports Sci ; 38(21): 2471-2478, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32662349

RESUMO

A logarithmic curve fitting methodology for the calculation of badminton racket-shuttlecock impact locations from three-dimensional motion capture data was presented and validated. Median absolute differences between calculated and measured impact locations were 3.6 [IQR: 4.4] and 3.5 [IQR: 3.5] mm mediolaterally and longitudinally on the racket face, respectively. Three-dimensional kinematic data of racket and shuttlecock were recorded for 2386 smashes performed by 65 international badminton players, with racket-shuttlecock impact location assessed against instantaneous post-impact shuttlecock speed and direction. Mediolateral and longitudinal impact locations explained 26.2% (quadratic regression; 95% credible interval: 23.1%, 29.2%; BF10 = 1.3 × 10131, extreme; p < 0.001) of the variation in participant-specific shuttlecock speed. A meaningful (BF10 = ∞, extreme; p < 0.001) linear relationship was observed between mediolateral impact location and shuttlecock horizontal direction relative to a line normal to the racket face at impact. Impact locations within one standard deviation of the pooled mean impact location predict reductions in post-impact shuttlecock speeds of up to 5.3% of the player's maximal speed and deviations in the horizontal direction of up to 2.9° relative to a line normal to the racket face. These results highlight the margin for error available to elite badminton players during the smash.


Assuntos
Desempenho Atlético/fisiologia , Destreza Motora/fisiologia , Esportes com Raquete/fisiologia , Fenômenos Biomecânicos , Humanos , Movimento , Equipamentos Esportivos , Estudos de Tempo e Movimento
12.
Sports Health ; 12(5): 488-494, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32598234

RESUMO

BACKGROUND: Baseball pitching injuries are increasing at an alarming rate. While weighted ball throwing programs may be effective at increasing pitching velocity, previous research has identified a 24% injury rate and a 3.3° increase in shoulder external rotation (ER) range of motion (ROM) after performing a 6-week program. However, previous research has not investigated, separately, the immediate effects of throwing underloaded and overloaded balls on ROM. The purpose of this study was to examine the acute effects of throwing differently weighted baseballs on shoulder ROM. By analyzing these differences, it may be possible to determine the specific weight range that may lead to the greatest increase in ROM and potential injury risk. HYPOTHESIS: Throwing with weighted balls will result in an increase in shoulder ER ROM. STUDY DESIGN: Randomized controlled trial. LEVEL OF EVIDENCE: Level 2. METHODS: A total of 16 male high school baseball pitchers agreed to participate in this study. The participants were (mean ± SD) 17.1 ± 1.0 years of age, 1.81 ± 0.09 m tall, and had a mass of 79.2 ± 11.1 kg. Each participant was tested on 3 different days, 1 week apart, with 3 different conditions in random order: (1) underload throwing, using regulation 5-oz baseballs and 4- and 2-oz balls; (2) overload throwing, using 5-, 6-, and 9-oz balls; and (3) extreme overload throwing, using 5-, 16-, and 32-oz balls. Each testing session began by measuring passive shoulder ROM (external rotation and internal rotation) using standard goniometric measurements. Participants then performed 3 throws with each weighted ball from 3 different positions (kneeling, rocker, and run-and-gun) for a total of 27 throws each test session. ROM measurements were repeated at the end of each test session. The effect of each throwing condition on ROM was compared from pre- to posttraining using a paired t test (P ≤ 0.05). RESULTS: There was no significant difference in ER after throwing at underloaded weights. The overload condition showed a statistically significant increase of 3.3° in external rotation (P = 0.05). The extreme overload condition showed a statistically significant increase in ER of 8.4° (P < 0.001). There were no differences in internal rotation for any group. CONCLUSION: A significant increase in shoulder ER was observed immediately after throwing overload weighted balls. This effect increased as the weights of the balls increased. CLINICAL RELEVANCE: Throwing with overload weighted baseballs causes an immediate increase in shoulder ER ROM. It is unknown why these changes occur; however, the results may explain both the increase in velocity and injury rates previously observed from throwing weighted balls. The current study results may be used to develop more scientifically validated weighted ball programs. Heavier balls should be used with caution, and ROM should be monitored during implementation of these programs.


Assuntos
Beisebol/fisiologia , Condicionamento Físico Humano/instrumentação , Condicionamento Físico Humano/métodos , Ombro/fisiologia , Equipamentos Esportivos , Adolescente , Beisebol/lesões , Humanos , Masculino , Amplitude de Movimento Articular , Estresse Mecânico
13.
J Sports Sci ; 38(19): 2236-2241, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32552333

RESUMO

Surface compliance has been shown to affect leg stiffness and energetics. It is unknown if compliance differences between common treadmills would elicit such changes. Therefore, the purpose of this study was to determine if compliance design differences of common treadmills would affect the mechanics and energetics of running. Eleven runners ran at moderate, self-selected, matched belt speeds for three minutes on two treadmills: compliant (CT) and rigid (RT) decks. During the last minute of each trial, oxygen consumption and six markers describing the torso, thigh, shank and foot, and one marker to determine treadmill deflection were recorded. Leg stiffness, continuous relative phase (CRP) and CRP variability were calculated. Compared to RT, running on CT resulted in a significantly more compliant leg (8.591 kN•m-1 > 9.063 kN•m-1), lower oxygen consumption (34.69 ml•kg-1•min-1 < 36.86 ml•kg-1•min-1), different coordination patterns and greater variability, particularly during the push-off phase. These results are inconsistent with the literature because the deck of CT rebounds back at the runner during the absorption phase and away from the runner during the push-off phase. Therefore, care should be taken when using treadmills for research and comparing mechanical and energetic measures between studies.


Assuntos
Desenho de Equipamento , Perna (Membro)/fisiologia , Corrida/fisiologia , Equipamentos Esportivos , Adulto , Fenômenos Biomecânicos , Metabolismo Energético , Feminino , Humanos , Masculino , Consumo de Oxigênio , Propriedades de Superfície
14.
J Sports Sci ; 38(18): 2127-2148, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32552520

RESUMO

Cross-country skiing is a complex endurance sport requiring technical skills, in addition to considerable physiological and tactical abilities. This review aims to identify biomechanical factors that influence the performance of cross-country skiers. Four electronic databases were searched systematically for original articles in peer-reviewed journals addressing the relationship between biomechanical factors (including kinematics, kinetics, and muscle activation) and performance while skiing on snow or roller skiing. Of the 46 articles included, 22 focused exclusively on the classical technique, 18 on the skating technique, and six on both. The indicators of performance were: results from actual or simulated races (9 articles); speed on specific tracts (6 articles); maximal or peak speed (11 articles); skiing economy or efficiency (11 articles); and grouping on the basis of performance or level of skill (12 articles). The main findings were that i) cycle length, most often considered as a major determinant of skiing speed, is also related to skiing economy and level of performance; ii) higher cycle rate related with maximal speed capacity, while self-selected cycle rate improves skiing economy at sub-maximal speeds; iii) cross-country skiing performance appears to be improved by joint, whole-body, ski, and pole kinematics that promote forward propulsion while minimizing unnecessary movement.


Assuntos
Desempenho Atlético/fisiologia , Destreza Motora/fisiologia , Esqui/fisiologia , Aceleração , Braço/fisiologia , Fenômenos Biomecânicos , Humanos , Cinética , Perna (Membro)/fisiologia , Músculo Esquelético/fisiologia , Equipamentos Esportivos
15.
J Sports Sci ; 38(18): 2118-2126, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32530736

RESUMO

Sport, like many industries, is experiencing growth in resources, professionalism and data generation. An understanding of how humans can effectively and efficiently interact with technology, computers and other machines to improve sports performance is still being developed. As a consequence, the landscape in which the performance analyst now finds themselves has fundamentally changed. New, improved and different skill sets are now required in order to be impactful and experience sustained success. However, this growth also presents new opportunities to address difficult problems, including many that were previously considered intractable. This article lists ten essential adaptive tools for the contemporary performance analyst, many of which are useful in both research and applied sporting environments. A rationale for each is proposed, with an emphasis on ensuring that the performance analyst will be equipped to thrive in both current and future sport environments.


Assuntos
Desempenho Atlético , Técnicas de Apoio para a Decisão , Sistemas Homem-Máquina , Análise e Desempenho de Tarefas , Humanos , Equipamentos Esportivos
16.
J Sport Health Sci ; 9(3): 258-264, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32444150

RESUMO

BACKGROUND: Q-Factor (QF), or the inter-pedal width, in cycling is similar to step-width in gait. Although increased step-width has been shown to reduce peak knee abduction moment (KAbM), no studies have examined the biomechanical effects of increased QF in cycling at different workrates in healthy participants. METHODS: A total of 16 healthy participants (8 males, 8 females, age: 22.4 ± 2.6 years, body mass index: 22.78 ± 1.43 kg/m2, mean ± SD) participated. A motion capture system and customized instrumented pedals were used to collect 3-dimensional kinematic (240 Hz) and pedal reaction force (PRF) (1200 Hz) data in 12 testing conditions: 4 QF conditions-Q1 (15.0 cm), Q2 (19.2 cm), Q3 (23.4 cm), and Q4 (27.6 cm)-under 3 workrate conditions-80 watts (W), 120 W, and 160 W. A 3 × 4 (QF × workrate) repeated measures of analysis of variance were performed to analyze differences among conditions (p < 0.05). RESULTS: Increased QF increased peak KAbM by 47%, 56%, and 56% from Q1 to Q4 at each respective workrate. Mediolateral PRF increased from Q1 to Q4 at each respective workrate. Frontal-plane knee angle and range of motion decreased with increased QF. No changes were observed for peak vertical PRF, knee extension moment, sagittal plane peak knee joint angles, or range of motion. CONCLUSION: Increased QF increased peak KAbM, suggesting increased medial compartment loading of the knee. QF modulation may influence frontal-plane joint loading when using stationary cycling for exercise or rehabilitation purposes.


Assuntos
Ciclismo/fisiologia , Articulação do Joelho/fisiologia , Equipamentos Esportivos , Artralgia/fisiopatologia , Fenômenos Biomecânicos , Desenho de Equipamento , Feminino , Humanos , Masculino , Percepção/fisiologia , Esforço Físico/fisiologia , Amplitude de Movimento Articular , Estudos de Tempo e Movimento , Adulto Jovem
17.
Int J Sports Med ; 41(11): 720-728, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32396965

RESUMO

The goal of this systematic review was to evaluate the effects of exercise programs using agility ladders and to assess the quality of available evidence. Search was conducted in October of 2019 using the following databases: Cochrane Library, PEDro, PubMed, Scopus and Web of Science. Study eligibility criteria included randomized trials or randomized controlled trials using agility ladders drills. Participants were healthy humans of any health status. The study appraisal and synthesis methods followed the revised Cochrane risk-of-bias tool for randomized trials (RoB 2) and a qualitative synthesis of the main results of each study were applied. Only five studies met our criteria, lasting between 4 and 8 weeks. Only two studies evaluated the effects of ladder drills on more than one dimension. Lack of description of the specific exercises that were used limits reproducibility of current studies. With one exception, the articles had low risk of bias for most domains. Despite the widespread popularity of agility ladder drills, research is scarce and problematic, with poorly described protocols and mostly unidimensional performance measures. Claims that agility ladders improve agility and other physical skills is premature, given the nature and quality of existing research.


Assuntos
Desempenho Atlético/fisiologia , Destreza Motora/fisiologia , Condicionamento Físico Humano/instrumentação , Condicionamento Físico Humano/métodos , Humanos , Projetos de Pesquisa/normas , Equipamentos Esportivos
18.
J Sports Sci ; 38(14): 1650-1659, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32310013

RESUMO

When executed correctly, swing bowling has the potential to influence the outcome of a cricket match, yet little is known about the required bowling action and ball flight characteristics. This study aimed to describe the bowling action and initial ball flight characteristics as well as to identify variables that may be associated with increased swing in pathway and high-performance medium and fast pace bowlers. A 17-camera Vicon motion analysis system captured retro-reflective markers placed on the upper-body of participants and new cricket balls to quantify bowling action and initial ball flight kinematics. Bowlers delivered the ball with their forearm and hand angled in the direction of intended swing with an extended wrist flexing through the point of ball release. Bowlers who produced more swing had increased seam stability, possibly linked to a lower wrist and ball angular velocity. It is believed that swing increases with seam stability, however, optimal ranges may exist for seam azimuth angle, ball angular velocity and release speed. These findings may assist coaches to optimise the performance of bowlers, however, future research should use bowlers who play at higher levels to investigate swing bowling at greater speeds.


Assuntos
Desempenho Atlético/fisiologia , Críquete/fisiologia , Equipamentos Esportivos , Extremidade Superior/fisiologia , Fenômenos Biomecânicos , Desenho de Equipamento , Feminino , Antebraço/fisiologia , Mãos/fisiologia , Humanos , Masculino , Destreza Motora/fisiologia , Rotação , Ombro/fisiologia , Tórax/fisiologia , Estudos de Tempo e Movimento , Punho/fisiologia , Adulto Jovem
19.
J Sports Sci ; 38(14): 1624-1628, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32299296

RESUMO

The aims of this study were to compare the force profile of using a horizontal cylinder-shaped axis or a vertical cone-shaped axis to provide resistance in rotary inertia devices, and to report the evolution of kinetic and kinematic variables in experienced athletes during a half-squat exercise. Twenty-two healthy active men participated in the assessment of time, peak velocity, peak force, time to reach the peak force, average force, impulse, and range of movement, during a half-squat incremental test performed on conical inertial device (CP) and on cylinder inertial device (YY). The analysis showed that YY during CON-ECC phased generates substantial higher peak_force, mean_force, impulse, time, and a lower peak_velocity, than CP. We never obtained eccentric overload for peak_force or mean_force. CP offers less resistance to accelerate-decelerate the movement with respect to YY, we need checking whether eccentric overload it is being produced, and the impulse was the only kinetic variable that was able to discriminate between the inertias and devices.


Assuntos
Treinamento de Resistência/instrumentação , Equipamentos Esportivos , Levantamento de Peso/fisiologia , Fenômenos Biomecânicos , Desenho de Equipamento , Humanos , Cinética , Masculino , Movimento/fisiologia , Adulto Jovem
20.
Int J Sports Physiol Perform ; 15(6): 884-891, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32244223

RESUMO

PURPOSE: To investigate how self-selected pole length (PL) of ∼84% (PL84%) compared with ∼90% (PL90%) of body height influenced performance during a 700-m time trial with undulating terrain on snow. METHODS: Twenty-one cross-country skiers, 7 of whom were women, performed 4 trials at a maximal effort in a counterbalanced fashion with PL84% and PL90% separated by 20-minute breaks between trials. In trials I and II, only double poling was allowed, while in trials III and IV, skiers used self-selected classical subtechniques. Continuous speed, cyclic parameters, and heart rate were collected using microsensors in addition to a post-time-trial rating of perceived exertion (RPE). RESULTS: The 700-m times with only double poling were significantly shorter with PL90% than PL84% (mean ± 95% confidence limits -1.6% ± 1.0%). Segment analyses showed higher speed with PL90% in uphill sections than with PL84% (3.7% ± 2.1%), with the greatest difference found for the female skiers (5.6% ± 2.9%). In contrast, on flat terrain at high skiing speeds, speed was reduced with PL90% compared with PL84% (-1.5% ± 1.4%); this was only significant for the male skiers. During free choice of classical subtechniques, PL did not influence performance in any segments, choice of subtechnique, or cycle rate during the trials. No differences in rating of perceived exertion or heart rate between PLs were found. CONCLUSIONS: PL90% improved performance in uphills at low speeds when using double poling but hindered performance on flat terrain and at higher speeds compared with self-selected PLs. Choice of PL should, therefore, be based on racecourse topography, preferred subtechniques, and the skier's physiological and technical abilities.


Assuntos
Desempenho Atlético/fisiologia , Esqui/fisiologia , Equipamentos Esportivos , Estatura , Feminino , Frequência Cardíaca/fisiologia , Humanos , Masculino , Destreza Motora/fisiologia , Percepção/fisiologia , Esforço Físico/fisiologia , Fatores Sexuais , Neve , Análise e Desempenho de Tarefas , Adulto Jovem
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