RESUMO
Beach volleyball (BV) is an intermittent sport characterised by short-duration and highly demanding activities with low intensity periods. Establishing if players' jump ability is influenced by sand granulometry is a useful information for sport scientists, coaches and players. This study aimed to assess the possible differences in the kinetics parameters of the vertical jump on different types of sand performed by BV players. Twelve elite female players performed six countermovement jumps (CMJs) in three different surface conditions (fine sand, reference, coarse sand) in a random counterbalanced order (216 jumps). A generalised mixed model approach detected differences for CMJ model in total duration (p: 0.016), eccentric phase duration (p: 0.007), concentric phase duration (p: 0.011), time to peak power (p: < 0.001), time to peak force (p: 0.014), maximum rate force development concentric phase (p: 0.004), maximum velocity (p: 0.028) and peak power eccentric (p: 0.018). Coarse sand decreases the time spent jumping compared to fine sand, without a penalty to jump height. Coaches and athletes should take this information into account to enhance their understanding of practice strategies and game conditions. One might anticipate a faster pace in games played on coarse sand and a slower pace on fine sand.
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This study provided a proof-of-concept and test-retest reliability of measures frequently used to assess a mental fatigue paradigm. After familiarization, 28 healthy men performed (40-min) the Rapid Visual Information Processing (RVP) test in a test-retest design, having mental fatigue sensation, motivation, emotional arousal, total mood disturbance, and electroencephalography (EEG) in the prefrontal cortex measured before and after the test. EEG was recorded during a 3-min rest so that the power spectral density of theta (3-7 Hz) and alpha (8-13 Hz) bands was calculated. Pre-to-post RVP test changes in psychological and physiological domains were compared (paired-T tests), and absolute (standard error of measurement (SEM) and minimal difference (MD)) and relative reliability (intraclass correlation coefficient (ICC)) were calculated. The RVP test induced an increase (p < 0.05) in mental fatigue sensation (120.9% (109.4; 132.4)) and total mood disturbance (3.5% (-6.3; 13.3)), and a decrease in motivation (-7.1% (-9.2; -5.1)) and emotional arousal (-16.2% (-19.1; -13.2)). Likewise, EEG theta (59.1% (33.2; 85.0); p < 0.05), but not alpha band, increased due to RVP test. All psychophysiological responses showed poor-to-moderate relative reliability. Changes in mental fatigue sensation and motivation were higher than SEM and MD, but changes in EEG theta band were higher only than SEM. Mental fatigue sensation, motivation, and EEG theta band were sensitive to distinguish a mental fatigue paradigm despite true mental fatigue effects on theta activity may be trivial.
Assuntos
Eletroencefalografia , Fadiga Mental , Humanos , Masculino , Motivação , Reprodutibilidade dos Testes , DescansoRESUMO
The aim of this study is to analyze how isokinetic knee and hip peak torques and roundhouse kick velocities are related to expertise level (elite vs. sub-elite) in taekwondo athletes. Seven elite and seven sub-elite athletes were tested for kick-specific variables (KSV, composed of kinematic variables and power of impact) and for concentric isokinetic peak torque (PT) at 60°/s and 240°/s. First, KSVs and PTs were compared between groups, then PTs were correlated with KSVs. Parametric variables with larger effect sizes (Cohen's d) were entered in a stepwise linear discriminant analysis (LDA), generating an equation to estimate competitive level. Between-group differences were found in hip flexors (p = 0.04, d = 0.92) and extensors (p = 0.04, d = 0.96) with PT at 240°/s. Hip flexion PT at 60°/s and 240°/s correlated negatively with kick time (R = -0.46, p = 0.0499 and R = -0.62, p = 0.01 respectively). Hip flexion torque at 60°/s correlated positively (R = 0.52, p = 0.03) with peak linear velocity of the foot (LVF) and power of impact (R = 0.51, p = 0.03). Peak torque of hip extension at 60°/s and hip abduction at 240°/s also correlated with LVF (R = 0.56, p = 0.02 and R = 0.46, p = 0.0499). Hip extension at 60°/s correlated positively with peak linear velocity of the knee (R = 0.48, p = 0.04). The LDA showed an accuracy of 85.7% (p = 0.003) in predicting expertise level based on hip flexion and extension torques at 240°/s and on knee extension velocity during the kick. The study demonstrates that hip muscle strength is probably the dominant muscular factor for determining kick performance. Knee angular velocity combined with hip torques is the best discriminator for competitive level in taekwondo athletes.
Assuntos
Desempenho Atlético/fisiologia , Exercício Físico , Perna (Membro)/fisiologia , Artes Marciais/fisiologia , Fenômenos Biomecânicos , Exercício Físico/fisiologia , Feminino , Humanos , Masculino , Torque , Adulto JovemRESUMO
Pain arising from exercise potentiates fatigue and impairs the performance of endurance exercise. We assessed neurophysiological and perceptual responses to endurance exercise performed under experimentally induced muscle pain by a model that separates muscle pain from muscle fatigue. After a series of pilot studies investigating different hypertonic saline volumes, 17 healthy males performed a preliminary VO2PEAK test before performing a familiarization of the cycling time-to-exhaustion exercise (80% of the peak power output in the VO2PEAK test). Participants, performed a baseline exercise session before the sessions with hypertonic and isotonic saline injections in the vastus lateralis of both legs, in a crossover and counterbalanced design. Neurophysiological and perceptual responses such as electroencephalography (EEG) in frontal, prefrontal, parietal, and motor cortex, electromyography (EMG) of the vastus lateralis and biceps femoris muscles, ratings of perceived exertion (RPE), pain sensation, and affective valence were measured at rest and during exercise. The hypertonic injection reduced the resting EEG alpha-beta ratio in the frontal and prefrontal cortex. When compared to exercise performed after the isotonic injection (430.5 ± 152.6 s), hypertonic injection shortened the time-to-exhaustion (357.5 ± 173.0 s), reduced the EMG of the assessed muscles, and increased the muscle co-contraction during exercise. The hypertonic injection also reduced the EEG alpha-beta ratio in the prefrontal and parietal cortex, increased RPE and pain sensation, and reduced affective valence during exercise. This proof-of-concept study showed that hypertonic injection-induced muscle pain reduced endurance performance, promoting centrally mediated alterations in motor command and cortical activation, as well as an interplay of perceptual responses.
Assuntos
Eletroencefalografia , Eletromiografia , Mialgia/induzido quimicamente , Resistência Física/fisiologia , Esforço Físico/fisiologia , Adulto , Ciclismo/fisiologia , Humanos , Masculino , Córtex Motor , Fadiga Muscular/fisiologia , Córtex Pré-Frontal , Músculo Quadríceps , Solução Salina HipertônicaRESUMO
BACKGROUND AND OBJECTIVE: Sepsis is a potentially deadly organic dysfunction, and one of the main causes of mortality in intensive care units (ICU). Aerobic exercise (AE) is a preventive intervention in the establishment of inflammatory conditions, such as chronic lung diseases, but its effects on sepsis remain unclear. Therefore, this study aimed to evaluate the effects of AE on health condition, mortality, inflammation, and oxidative damage in an experimental model of pneumosepsis induced by Klebsiella pneumoniae (K.p). METHODS: Animals were randomly allocated to Control; Exercise (EXE); Pneumosepsis (PS) or Exercise + Pneumosepsis (EPS) groups. Exercised animals were submitted to treadmill exercise for 2 weeks, 30 min/day, prior to pneumosepsis induced by K.p tracheal instillation. RESULTS: PS produced a striking decrease in the health condition leading to massive death (85%). AE protected mice, as evidenced by better clinical scores and increased survival (70%). AE alleviated sickness behavior in EPS mice as evaluated in the open field test, and inflammation (nitrite + nitrate, TNF-α and IL-1ß levels) in broncoalveolar fluid. Catalase activity, oxidative damage to proteins and DNA was increased by sepsis and prevented by exercise. CONCLUSION: Overall, the beneficial effects of exercise in septic animals encompassed a markedly improved clinical score and decreased mortality, along with lower inflammation markers, less DNA and protein damage, as well as preserved antioxidant enzyme activity. Neural network risk analysis revealed exercise had a considerable effect on the overall health condition of septic mice.
Assuntos
Dano ao DNA/fisiologia , DNA/metabolismo , Condicionamento Físico Animal/fisiologia , Pneumonia/metabolismo , Pneumonia/fisiopatologia , Sepse/metabolismo , Sepse/fisiopatologia , Animais , Biomarcadores/metabolismo , Modelos Animais de Doenças , Interleucina-1beta/metabolismo , Pulmão/metabolismo , Pulmão/fisiopatologia , Masculino , Camundongos , Estresse Oxidativo/fisiologia , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Detrimental mental fatigue effects on exercise performance have been documented in constant workload and time trial exercises, but effects on a maximal incremental test (MIT) remain poorly investigated. Mental fatigue-reduced exercise performance is related to an increased effort sensation, likely due to a reduced prefrontal cortex (PFC) activation and inhibited spontaneous behavior. Interestingly, only a few studies verified if centrally active compounds may mitigate such effects. For example, carbohydrate (CHO) mouth rinse potentiates exercise performance and reduces effort sensation, likely through its effects on PFC activation. However, it is unknown if this centrally mediated effect of CHO mouth rinse may mitigate mental fatigue-reduced exercise performance. After a proof-of-principle study, showing a mental fatigue-reduced MIT performance, we observed that CHO mouth rinse mitigated MIT performance reductions in mentally fatigued cyclists, regardless of PFC alterations. When compared to placebo, mentally fatigued cyclists improved MIT performance by 2.24-2.33% when rinsing their mouth with CHO during MIT. However, PFC and motor cortex activation during MIT in both CHO and placebo mouth rinses were greater than in mental fatigue. Results showed that CHO mouth rinse mitigated the mental fatigue-reduced MIT performance, but challenged the role of CHO mouth rinse on PFC and motor cortex activation.
RESUMO
The central and peripheral effects of caffeine remain debatable. We verified whether increases in endurance performance after caffeine ingestion occurred together with changes in primary motor cortex (MC) and prefrontal cortex (PFC) activation, neuromuscular efficiency (NME), and electroencephalography-electromyography coherence (EEG-EMG coherence). Twelve participants performed a time-to-task failure isometric contraction at 70% of the maximal voluntary contraction after ingesting 5 mg/kg of caffeine (CAF) or placebo (PLA), in a crossover and counterbalanced design. MC (Cz) and PFC (Fp1) EEG alpha wave and vastus lateralis (VL) muscle EMG were recorded throughout the exercise. EEG-EMG coherence was calculated through the magnitude squared coherence analysis in MC EEG gamma-wave (CI > 0.0058). Moreover, NME was obtained as the force-VL EMG ratio. When compared to PLA, CAF improved the time to task failure (p = 0.003, d = 0.75), but reduced activation in MC and PFC throughout the exercise (p = 0.027, d = 1.01 and p = 0.045, d = 0.95, respectively). Neither NME (p = 0.802, d = 0.34) nor EEG-EMG coherence (p = 0.628, d = 0.21) was different between CAF and PLA. The results suggest that CAF improved muscular performance through a modified central nervous system (CNS) response rather than through alterations in peripheral muscle or central-peripheral coupling.
Assuntos
Ritmo alfa/efeitos dos fármacos , Cafeína/administração & dosagem , Córtex Motor/efeitos dos fármacos , Contração Muscular/efeitos dos fármacos , Substâncias para Melhoria do Desempenho/administração & dosagem , Resistência Física/efeitos dos fármacos , Córtex Pré-Frontal/efeitos dos fármacos , Músculo Quadríceps/inervação , Adulto , Ciclismo , Cafeína/efeitos adversos , Estudos Cross-Over , Método Duplo-Cego , Eletromiografia , Humanos , Córtex Motor/fisiologia , Fadiga Muscular , Força Muscular/efeitos dos fármacos , Substâncias para Melhoria do Desempenho/efeitos adversos , Córtex Pré-Frontal/fisiologia , Fatores de TempoRESUMO
PURPOSE: To verify whether caffeine (CAF) could increase the prefrontal cortex (PFC) activation and improve 20â¯km cycling time trial (TT20km) performance in mentally fatigued cyclists. METHODS: After preliminary TT20km, twelve recreational cyclists (VO2MAX of 58.9⯱â¯6.2â¯mLâ¯kgâ¯min-1) performed a familiarization with a cognitive test to induce mental fatigue (MF) and psychological scales. Thereafter, they performed: 2) a baseline TT20km; 3) a mentally fatigued TT20km (MF); 4 and 5) a mentally fatigued TT20km after CAF (MFâ¯+â¯CAF) or placebo (MFâ¯+â¯PLA) ingestion, in a double-blind, counterbalanced design. Performance and psychological responses were obtained throughout the TT20km, while PFC electroencephalography (EEG) theta wave was obtained before and after the mental fatigue test. RESULTS: The mental fatigue-induced increase in EEG theta wave (↑â¯~â¯4.8%) was reverted with CAF (↓â¯8.8%) and PLA ingestion (↓â¯4.8%). CAF improved TT20km performance in mentally fatigued cyclists by reducing time (pâ¯=â¯.00; ↓â¯~â¯1.7%) and increasing WMEAN (pâ¯=â¯.00; ↑â¯~â¯3.6%), when compared to MFâ¯+â¯PLA. The RPE-power output ratio was lower (pâ¯=â¯.01), but affect (pâ¯=â¯.018), motivation (pâ¯=â¯.033) and emotional arousal (pâ¯=â¯.001) were greater throughout the TT20km in MFâ¯+â¯CAF than in MFâ¯+â¯PLA. CONCLUSIONS: CAF ingestion improved TT20km performance and psychological responses in mentally fatigued cyclists, despite the unaltered PFC activation.
Assuntos
Desempenho Atlético , Ciclismo , Cafeína/farmacologia , Estimulantes do Sistema Nervoso Central/farmacologia , Fadiga Mental/tratamento farmacológico , Fadiga Mental/psicologia , Córtex Pré-Frontal/efeitos dos fármacos , Adulto , Nível de Alerta/efeitos dos fármacos , Cognição/efeitos dos fármacos , Método Duplo-Cego , Eletroencefalografia/efeitos dos fármacos , Humanos , Masculino , Motivação/efeitos dos fármacos , Resistência Física , Ritmo Teta/efeitos dos fármacosRESUMO
INTRODUÇÃO: Dinamômetro isocinético é um equipamento eletrônico e mecânico, capaz de medir o torque gerado por um determinado segmento, bem como a potência e estimar fadiga, observando-se a variação do torque ao longo tempo. Este dispositivo também controla a velocidade do movimento angular, seja ele gerado por uma contração excêntrica ou concêntrica. Este tipo de equipamento tem sido utilizado tanto para avaliação como para treinamento de força. OBJETIVO: Verificar o efeito do treinamento de força, realizado exclusivamente no dinamômetro isocinético, na capacidade de gerar torque isométrico. MÉTODO: 2 homens, sedentários, saudáveis com idade de 23 e 24 anos realizaram 16 sessões de treinamento de força (sempre em esforço máximo e no modo concêntrico utilizando-se um dinamômetro isocinético) para os músculos flexores da articulação do cotovelo do membro dominante. As sessões foram compostas por um treinamento de quatro séries de oito repetições em uma amplitude de movimento de 130º, com velocidade fixada em 45º/s. As avaliações de contração isométrica voluntária máxima (CIVM) a 90º de flexão da articulação do cotovelo foram realizadas na primeira, oitava e décima sexta sessão. Espessura dos músculos flexores da articulação do cotovelo também foi medida, com ultrassonografia, nas mesmas sessões em que o torque máximo isométrico foi medido. RESULTADOS: Não houve diferença significativa no ganho de torque tam pouco na espessura muscular, ao final do treinamento. CONCLUSÃO: Treinamento de força, exclusivamente realizado no modo concêntrico no dinamômetro isocinético não provocou aumento da capacidade de gerar força isométrica, tam pouco aumento da espessura muscular. [AU]
INTRODUCTION: Isokinetic dynamometer is an electromechanical device that allows measuring the torque of a segment, as well as estimating power and fatigue by observing the variation of torque over time. This device also controls the speed of the angular movement, whether it is generated by an eccentric or concentric contraction. This equipment is utilized for both evaluation and strength training. OBJECTIVE: Verify the effects of strength training performed on an isokinetic dynamometer on the capacity to generate isometric torque. METHOD: Two healthy, sedentary men, aged 23 e 24 performed 16 strength training sessions (always at maximum effort) for elbow joint flexor muscles of the dominant limb. The sessions were composed by a training of four sets of eight repetitions in a range of movement of 130°, at 45º/s. The evaluations of maximal voluntary isometric contraction (MVIC) in a 90º of elbow flexion was realized in the first, eighth and sixteenth sessions. Thickness of the flexor muscles of the elbow joint was also measured with ultrasonography at the same sessions in which the maximum isometric torque was measured. RESULTS: There was no significant difference in torque gain or in muscle thickness at the end of the training protocol. CONCLUSION: Strength training, exclusively performed in the concentric mode on an isokinetic dynamometer did not caused an increase in the capacity to generate isometric torque and did not change muscle thickness. [AU]
Assuntos
Força Muscular , Esforço Físico , Dinamômetro de Força MuscularRESUMO
ABSTRACT Introduction: The jump landing is the leading cause for ankle injuries in basketball. It has been shown that the use of ankle brace is effective to prevent these injuries by increasing the mechanical stability of the ankle at the initial contact of the foot with the ground. Objective: To investigate the effects of ankle brace on the ground reaction force (GRF) during the simulation of a basketball rebound jump. Method: Eleven young male basketball players randomly carried out a simulated basketball rebound jump under two conditions, with and without ankle brace (lace-up). Dynamic parameters of vertical GRF (take-off and landing vertical peaks, time to take-off and landing vertical peaks, take-off impulse peak, impulse at 50 milliseconds of landing, and jump height) and medial-lateral (take-off and landing medial-lateral peaks, and time to reach medial-lateral peaks at take-off and landing) were recorded by force platform during rebound jumps in each tested condition. The comparisons between the tested conditions were performed by paired t test (P<0.05). Results: The use of ankle braces reduced the medial and lateral peaks of the GRF by -15.7% (P=0.035) and -24.9% (P=0.012), respectively, during the landing of the rebound jump. Additionally, wearing the brace did not affect any dynamic parameters of vertical GRF or temporal parameters of the medial-lateral GRF (P>0.05). Conclusion: The use of ankle brace during basketball rebound jumps attenuates the magnitude of medial-lateral GRF on the landing phase, without changing the vertical GRF. This finding indicates that the use of brace increases the medial-lateral mechanical protection by decreasing the shear force exerted on the athlete's body without change the application of propulsive forces in the take-off and the impact absorption quality in the landing during the basketball rebound jump.
RESUMO Introdução: A aterrissagem do salto é a principal causa de lesões de tornozelo no basquetebol. Demonstrou-se que o uso de órtese de tornozelo é efetivo para prevenir estas lesões, porque aumenta a estabilidade mecânica do tornozelo no contato inicial do pé com o solo. Objetivo: Investigar os efeitos do uso de órtese de tornozelo sobre a força de reação do solo (FRS) durante simulação de um salto de rebote do basquetebol. Método: Onze jovens jogadores de basquetebol do sexo masculino realizaram randomicamente um salto de rebote do basquetebol simulado em duas condições, com e sem órtese de tornozelo (lace-up). Os parâmetros dinâmicos da FRS vertical (picos verticais na decolagem e aterrissagem, tempo até os picos verticais na decolagem e aterrissagem, pico de impulso na decolagem, impulso nos 50 milissegundos da aterrissagem e altura do salto) e mediolateral (picos mediolaterais na decolagem e aterrissagem e tempo para atingir os picos mediolaterais na decolagem e aterrissagem), foram registrados por plataforma de força durante os saltos de rebote em cada condição testada. As comparações entre as condições testadas foram realizadas pelo teste t pareado (P < 0,05). Resultados: O uso de órteses de tornozelo reduziu os picos mediais e laterais da FRS em -15,7% (P = 0,035) e -24,9% (P = 0,012), respectivamente, durante a aterrissagem do salto de rebote. Além disso, o uso da órtese de tornozelo não afetou nenhum parâmetro dinâmico da FRS vertical ou parâmetros temporais da FRS mediolateral (P > 0,05). Conclusão: O uso de órtese de tornozelo durante os saltos de rebote do basquetebol atenua a magnitude da FRS mediolateral na fase aterrissagem, sem alterar a FRS vertical. Esse achado indica que o uso de órtese aumenta a proteção mecânica mediolateral pela redução da força de cisalhamento exercida sobre o corpo do atleta, sem alterar a aplicação das forças de propulsão na decolagem e a qualidade de absorção de impacto na aterrissagem durante o salto de rebote do basquetebol.
RESUMEN Introducción: El aterrizaje del salto es la principal causa de lesiones de tobillo en el baloncesto. Se ha demostrado que el uso de ortesis para tobillo es eficaz para evitar este tipo de lesiones, ya que aumenta la estabilidad mecánica del tobillo en el contacto inicial del pie con el suelo. Objetivo: Investigar los efectos del uso de ortesis para tobillo sobre la fuerza de reacción del suelo (FRS) durante la simulación de un salto de rebote de baloncesto. Métodos: Once jóvenes del sexo masculino, jugadores de baloncesto, fueron sometidos al azar a un salto de rebote simulado de baloncesto en dos condiciones, con y sin ortesis para tobillo (lace-up). Los parámetros dinámicos de la FRS vertical (picos verticales en el despegue y aterrizaje, tiempo hasta el pico vertical en el despegue y el aterrizaje, el empuje de pico en el despegue, el empuje en 50 milisegundos de aterrizaje y altura del salto) y mediolateral (picos mediolaterales en el despegue y el ater-rizaje y el tiempo para alcanzar el pico mediolateral en el despegue y el aterrizaje) fueron registrados por la plataforma de fuerza durante el salto de rebote. Las comparaciones entre las condiciones estudiadas se realizaron mediante la prueba t pareada (P < 0,05). Resultados: El uso de la ortesis para tobillo redujo los picos mediales y laterales de la FRS en -15,7% (P = 0,035) y -24,9% (P = 0,012), respectivamente, durante el aterrizaje del salto rebote. Además, el uso de ortesis para tobillo no afectó a ningún parámetro dinámico de la FRS vertical o parámetros temporales de la FRS mediolateral (P > 0,05). Conclusión: El uso de ortesis para tobillo para el salto de rebote de baloncesto atenúa la magnitud de la FRS mediolateral en el fase de aterrizaje sin cambiar el FRS vertical. Este hallazgo indica que el uso de la ortesis aumenta la protección mecánica mediolateral al reducir la fuerza de corte ejercida sobre el cuerpo del atleta, sin cambiar la aplicación de las fuerzas de propulsión en el despegue y la calidad de absorción de impactos en el aterrizaje del salto durante el rebote en el baloncesto.
RESUMO
Resumo O objetivo do estudo foi comparar o comportamento do COP e do sentido de posição articular passivo em indivíduos com e sem instabilidade de tornozelo, e correlacionar as variáveis de COP e sentido de posição articular passivo. Participaram 20 indivíduos, divididos em dois grupos: grupo estável (GE) e grupo instável (GI). A avaliação do COP foi feita com o teste de apoio unipodal, com olhos abertos e fechados sobre uma plataforma de força. O teste de reposicionamento articular passivo foi realizado com os olhos vendados. O tornozelo foi posicionado em um ângulo alvo (10° e 20°) e o dinamômetro movia passivamente o tornozelo, então os participantes eram instruídos a apertar o botão para parar o movimento quando sentissem que o tornozelo estava no ângulo alvo, obtendo assim o erro angular absoluto (EAA). Foram obtidas as variáveis: deslocamento total (DT); desvio padrão ântero-posterior (DPap) e médio-lateral (DPml); velocidade média total (VMT); velocidade média ântero-posterior (VMap) e médio-lateral (VMml). A comparação entre dados que apresentaram distribuição normal foi feita com o teste t de Student, enquanto que para DT e DPml foi utilizado o teste de Mann-Whitney. Da mesma forma, foram usados os testes de Pearson e Spearman para correlacionar as variáveis. Foi adotado α < 0,05. Houve diferença entre EAA-10° (p < 0,05). Foram encontradas fortes correlações entre: EAA-10° e VMT (p < 0,01 r = −0,867); EAA-10° e VMap (p < 0,01 r = −0,854); EAA-10° e VMml (p < 0,01 r = −0,771), na condição olhos abertos, e EAA-10° e DT (p < 0,05 r = −0,666); EAA-10° e DPap (p < 0,05 r = −0,685) e EAA-10° e VMml (p < 0,05 r = −0,766) na condição olhos fechados. Entorses de tornozelo prejudicam o sentido de posição, sem afetar o equilíbrio.(AU)
Abstract The aim of the study was to compare the behavior of COP and passive ankle position sense in subjects with and without functional ankle instability. Took part in this study 20 subjects, divided into two groups: stable group (SG) and unstable group (UG). The COP evaluation was made with the single-leg balance test, with eyes opened and closed, on a force plate. The passive ankle position sense test was performed with subjects blindfolded. The ankle was positioned in a target angle (10° and 20°) and the dynamometer moved passively the ankle, then the subjects were instructed to push the stop button when they feel that the ankle was on the target angle, obtaining the absolute angular error (AAE). The following variables were obtained: total displacement (TD); antero-posterior (SDap) and medio-lateral standard deviation (SDml); total mean velocity (TMV); antero-posterior (MVap) and medio-lateral mean velocity (MVml). The comparison between the data with normal distribution was made with the Student's t test, while to the TD and SDml was used the Mann-Whitney test. The correlations were performed with the Pearson and Spearman tests. We adopted α < 0.05. We observed difference between AAE-10° (p < 0.05). Strong correlations were found between: AAE-10° and TMV (p < 0.01 r = −0.867); AAE-10° and MVap (p < 0.01 r = −0.854); AAE-10° and MVml (p < 0.01 r = −0.771), with eyes opened, and AAE-10° and TD (p < 0.05 r = −0.666); AAE-10° and SDap (p < 0.05 r = −0,685) and AAE-10° and MVml (p < 0.05 r= −0.766) with eyes closed. Ankle sprains harm the joint position sense without affecting the balance.(AU)
Assuntos
Humanos , Masculino , Adulto , Tornozelo , Fenômenos Biomecânicos , Propriocepção , Entorses e DistensõesRESUMO
Background : Kinesio Taping (KT) is widely used, however the effects of KT on muscle activation and force are contradictory. Objective : To evaluate the effects of KT on knee extension force in soccer players. Method: This is a clinical trial study design. Thirty-four subjects performed two maximal isometric voluntary contractions of the lower limbs pre, immediately post, and 24 hours after tape application on the lower limbs. Both lower limbs were taped, using K-Tape and 3M Micropore tape randomly on the right and left thighs of the participants. Isometric knee extension force was measured for dominant side using a strain gauge. The following variables were assessed: peak force, time to peak force, rate of force development until peak force, time to peak rate of force development, and 200 ms pulse. Results : There were no statistically significant differences in the variables assessed between KT and Micropore conditions (F=0.645, p=0.666) or among testing sessions (pre, post, and 24h after) (F=0.528, p=0.868), and there was no statistical significance (F=0.271, p=0.986) for interaction between tape conditions and testing session. Conclusion: KT did not affect the force-related measures assessed immediately and 24 hours after the KT application compared with Micropore application, during maximal isometric voluntary knee extension. .
Assuntos
Humanos , Masculino , Feminino , Adulto Jovem , Futebol , Fita Atlética , Articulação do Joelho/fisiologia , Distribuição Aleatória , Amplitude de Movimento ArticularRESUMO
BACKGROUND: Kinesio Taping (KT) is widely used, however the effects of KT on muscle activation and force are contradictory. OBJECTIVE: To evaluate the effects of KT on knee extension force in soccer players. METHOD: This is a clinical trial study design. Thirty-four subjects performed two maximal isometric voluntary contractions of the lower limbs pre, immediately post, and 24 hours after tape application on the lower limbs. Both lower limbs were taped, using K-Tape and 3M Micropore tape randomly on the right and left thighs of the participants. Isometric knee extension force was measured for dominant side using a strain gauge. The following variables were assessed: peak force, time to peak force, rate of force development until peak force, time to peak rate of force development, and 200 ms pulse. RESULTS: There were no statistically significant differences in the variables assessed between KT and Micropore conditions (F=0.645, p=0.666) or among testing sessions (pre, post, and 24h after) (F=0.528, p=0.868), and there was no statistical significance (F=0.271, p=0.986) for interaction between tape conditions and testing session. CONCLUSION: KT did not affect the force-related measures assessed immediately and 24 hours after the KT application compared with Micropore application, during maximal isometric voluntary knee extension.