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Search Results: 1 - 10 of 23517 matches for " Fernando Diefenthaeler "
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O ENVOLVIMENTO DO TECIDO NEURAL NAS ENTORSES DE TORNOZELO
Bernardo Beltrame Rodrigues,Fernando Diefenthaeler
Brazilian Journal of Biomotricity , 2008,
Abstract: RODRIGUES, B. B.; DIEFENTHAELER, F. O envolvimento do tecido neural nas entorses de tornozelo. Brazilian Journal of Biomotricity, v. 2, n. 3, p. 145-154, 2008.The ankle sprains are among the most common lesions of the musculoskeletal system. These lesions occurred in the great majority due to the inversion movement, and it ends up provoking the lateral compartment of the ankle. In the midst of these structures damaged are the ligaments, the articulate capsule and possibly the neural tissue. In the neuralmusculoskeletal pathologies is essential the identification of the injured structures before the physiotherapic treatment application or the exercises prescription. This article supplies a bibliographical revision of researches about the involvement of the neural tissue during the ankle inversion sprains, fundament in the anatomy, biomechanics and neurodynamic of the ankle articulation. The commitment of the neural tissue in others pathologies and the accomplishment of experimental studies, appear as suggestions for future researches.
Aspectos relacionados à fadiga durante o ciclismo: uma abordagem biomecanica
Diefenthaeler, Fernando;Vaz, Marco Aurélio;
Revista Brasileira de Medicina do Esporte , 2008, DOI: 10.1590/S1517-86922008000500014
Abstract: muscular fatigue can be defined as functional inability to maintain a desired force output. during cycling competition, especially road races, cyclists are required to exercise for extended duration at high intensities. these features often result in fatigue, which can be associated with metabolic mechanisms and factors affecting both muscles (peripheral fatigue) and the central nervous system (central fatigue). the aim of this study is to review aspects related to alterations in the pedaling technique and electrical activation of the muscles during a fatiguing exercise bout. some of these alterations have been reported in the literature and can reflect on the (1) magnitude, direction, and sign of the forces applied on the pedal; (2) muscle activation pattern; (3) force generation; (4) and consequent performance of the cyclist. however, few studies have associated fatigue with pedal forces and muscle activation. the results of the reviewed studies have shown that cyclists failed to maintain a preset force level, alteration in the pedaling technique, and changes on the muscle activation pattern during cycling under fatigue condition.
Análise da técnica de pedalada durante o ciclismo até a exaust?o
Diefenthaeler, Fernando;Bini, Rodrigo Rico;Vaz, Marco Aurélio;
Motriz: Revista de Educa??o Física , 2012, DOI: 10.1590/S1980-65742012000300008
Abstract: the aim of this study was to investigate the effects of fatigue on the pedaling technique during maximal cycling test until exhaustion. eight well-trained cyclists completed an incremental test and a constant workload cycling test until exhaustion with 48 hours of rest. the resultant (fr) and effective (fe) forces were calculated to obtain the index of effectiveness (ie). fe increased from the start to the end of the test (from 125 ± 16 to 169 ± 52 n, p=0.03), whereas no differences were observed for ie and fr (from 0.55 ± 0.10 to 0.59 ± 0.08, p=0.14; from 230 ± 33 to 284 ± 72 n, p=0.08, respectively). increases in ankle joint range of motion were observed (from 19o ± 4.69 to 28 ± 7.29o, p<0.01). results suggest that during cycling until exhaustion well-trained cyclists are able to sustain the pedaling technique, which can be an important strategy in order to sustain the power output.
Frequency band analysis of muscle activation during cycling to exhaustion
Diefenthaeler, Fernando;Bini, Rodrigo Rico;Vaz, Marco Aurélio;
Revista Brasileira de Cineantropometria & Desempenho Humano , 2012, DOI: 10.5007/1980-0037.2012v14n3p243
Abstract: lower limb muscles activation was assessed during cycling to exhaustion using frequency band analysis. nine cyclists were evaluated in two days. on the first day, cyclists performed a maximal incremental cycling exercise to measure peak power output, which was used on the second day to define the workload for a constant load time to exhaustion cycling exercise (maximal aerobic power output from day 1). muscle activation of vastus lateralis (vl), long head of biceps femoris (bf), lateral head of gastrocnemius (gl), and tibialis anterior (ta) from the right lower limb was recorded during the time to exhaustion cycling exercise. a series of nine band-pass butterworth digital filters was used to analyze muscle activity amplitude for each band. the overall amplitude of activation and the high and low frequency components were defined to assess the magnitude of fatigue effects on muscle activity via effect sizes. the profile of the overall muscle activation during the test was analyzed using a second order polynomial, and the variability of the overall bands was analyzed by the coefficient of variation for each muscle in each instant of the test. substantial reduction in the high frequency components of vl and bf activation was observed. the overall and low frequency bands presented trivial to small changes for all muscles. high relationship between the second order polynomial fitting and muscle activity was found (r2 > 0.89) for all muscles. high variability (~25%) was found for muscle activation at the four instants of the fatigue test. changes in the spectral properties of the emg signal were only substantial when extreme changes in fatigue state were induced.
Influência da pedalada com os joelhos tangenciando o quadro da bicicleta sobre a ativa??o dos músculos do membro inferior
Bini, Rodrigo Rico;Carpes, Felipe Pivetta;Diefenthaeler, Fernando;
Revista Brasileira de Educa??o Física e Esporte , 2011, DOI: 10.1590/S1807-55092011000100004
Abstract: cyclist's body position on the bike has been related to changes in muscle activation. therefore, the aim of the present study was to compare the activation of tibialis anterior, gastrocnemius medialis, biceps femoris, rectus femoris, vastus lateralis, adductor longus e gluteus maximus muscles in three conditions: 1) reference position (preferred position); 2) adduction position (knees almost touching the bicycle frame); 3) abduction position (knees away from the bicycle frame). six athletes with competitive experience in cycling were evaluated using surface electromyography. they pedalled using their own bicycles mounted on a wind-trainer, with a workload relative to the second ventilatory threshold. muscle activation was defined by the mean value of the rms envelope and by the activation period for the three evaluated positions. there were no significant differences in muscles' rms or activation period between the three positions, except for the adductor longus muscle. in adduction position, this muscle was more activated (36 ± 6%), compared to the abduction position (25 ± 11%) for a significance level of p = 0.02, without significant differences for the reference position (27 ± 7%). these results indicate that there is no substantial difference in the activation of the most important muscles of the lower limb when the position of the knee is changed in the frontal plane for the same workload level, with the adductor longus as an exception.
Frequency band analysis of muscle activation during cycling to exhaustion.DOI: http://dx.doi.org/10.5007/1980-0037.2012v14n3p243
Fernando Diefenthaeler,Rodrigo Rico Bini,Marco Aurélio Vaz
Revista Brasileira de Cineantropometria e Desempenho Humano , 2012,
Abstract: Lower limb muscles activation was assessed during cycling to exhaustion using frequency band analysis. Nine cyclists were evaluated in two days. On the first day, cyclists performed a maximal incremental cycling exercise to measure peak power output, which was used on the second day to define the workload for a constant load time to exhaustion cycling exercise (maximal aerobic power output from day 1). Muscle activation of vastus lateralis (VL), long head of biceps femoris (BF), lateral head of gastrocnemius (GL), and tibialis anterior (TA) from the right lower limb was recorded during the time to exhaustion cycling exercise. A series of nine band-pass Butterworth digital filters was used to analyze muscle activity amplitude for each band. The overall amplitude of activation and the high and low frequency components were defined to assess the magnitude of fatigue effects on muscle activity via effect sizes. The profile of the overall muscle activation during the test was analyzed using a second order polynomial, and the variability of the overall bands was analyzed by the coefficient of variation for each muscle in each instant of the test. Substantial reduction in the high frequency components of VL and BF activation was observed. The overall and low frequency bands presented trivial to small changes for all muscles. High relationship between the second order polynomial fitting and muscle activity was found (R2 > 0.89) for all muscles. High variability (~25%) was found for muscle activation at the four instants of the fatigue test. Changes in the spectral properties of the EMG signal were only substantial when extreme changes in fatigue state were induced.
Comparative study of anthropometric variables in female classical ballet dancers, volleyball players and physically active subjects
Viviane Bortoluzzi Frasson,Fernando Diefenthaeler,Marco Aurélio Vaz
Revista Brasileira de Cineantropometria e Desempenho Humano , 2009,
Abstract: The objective of this study was to compare anthropometric variables (body weight, height, and percent body fat) and plantarflexion and dorsiflexion range of motion (ROM) between three different groups of women: classical ballet dancers (n=14), volleyball players (n=22) and physically active subjects (n=13). The assumption was that different functional requirements should produce differences in the anthropometric variables and ROM between the three groups. Body weight and height were higher in volleyball players (66.42 ± 5.8 kg; 174.77 ± 5.6 cm), followed by physically active women (59.93 ±10.3 kg; 164 ± 7.5 cm) and ballet dancers (49.25 ± 4.5 kg; 157.03 ± 3.6 cm) (p<0.05). Percent body fat was higher in physically active women (30.67 ± 4.6%) compared to theother two groups, which showed similar percentages (volleyball players: 24.93 ± 4.1%; ballet dancers: 21.94 ± 4.3%). The three groups were similar in terms of total ankle ROM and active dorsiflexion ROM between the right and left sides. However, plantarflexion ROM was higher in ballet dancers (~83°), followed by physically active women (~68°) and volleyball players who presented the smallest ROM (~60°). The different requirements imposed by the three distinct physical activities seem to be responsible for changes in some of the anthropometric variables and ankle joint ROM.
Effects of knee frontal plane position on pedal forces during cycling: A preliminary study
Rodrigo Rico Bini,Felipe Pivetta Carpes,Fernando Diefenthaeler
Revista Brasileira de Cineantropometria e Desempenho Humano , 2009,
Abstract: The purpose of this study was to compare the force applied to the pedal when cycling with the knees almost touching the bicycle frame (adduction position) compared to the position usually adopted by cyclists (reference position) and a position of the knees away from the bicycle frame (abduction position). Six cyclists were evaluated. Maximal oxygen uptake (VO2MAX) was defined, and then the three different knee positions on the frontal plane were assessed. Three minutes of cycling in the reference position, adduction position and abduction position were conducted, using oxygen uptake (VO2) at which the cyclists had achieved the second ventilatory threshold. An instrumented two-dimensional pedal was used to measure the forces applied to the right pedal. The average VO2 and power output did not differ between the adduction (50.4±6.9 ml.kg-1.min-1 and 263±29 W), abduction (50.8±5.9 ml.kg-1.min-1 and 250±46 W) and reference position (50.4±5.9 ml.kg-1.min-1 and 246±47 W). Pedaling cadence increased significantly during adduction (94±8 rpm) and abduction (95±5 rpm) compared to the reference position (89±8 rpm). The force results indicated no differences in the effective force or effectiveness index between the reference, adduction and abduction positions. Resultant force increased during adduction (284.5±44.5 N) compared to the reference position (246.9±39.2 N). The results indicate that the cyclists were able to generate higher resultant force during cycling with the knees close to the bicycle frame, but were unable to effectively transmit this force to the movement.
Preference and torque asymmetry for elbow joint
Carpes, Felipe Pivetta;Geremia, Jeam Marcel;Karolczak, Ana Paula Barcellos;Diefenthaeler, Fernando;Vaz, Marco Aurélio;
Motriz: Revista de Educa??o Física , 2012, DOI: 10.1590/S1980-65742012000200012
Abstract: extensively unilateral recruitment for daily activities may determine performance asymmetries in favor of the preferred side eliciting functional adaptation. our study evaluated asymmetries in elbow torque output between preferred and non-preferred limbs. eighteen subjects performed maximal elbow flexor and extensor isometric contractions at five different elbow joint angles (0o, 30o, 60o, 90o, 120o) and five different angular velocities (60, 120, 180, 240, 300o.s-1) on an isokinetic dynamometer. higher flexor torque in favor of preferred arm was observed at 90o of flexion (p<0.05), which also corresponded to the highest torque produced (p<0.05). the fact that joint angle influenced torque asymmetries, whereas angular velocity did not, suggest that the observed asymmetry is likely related to preferential recruitment of elbow flexors at a 90o joint angle for daily tasks requiring high levels of force production. muscle functional adaptation to frequent stimuli at this joint angle in healthy subjects may explain these results.
Esfor?o percebido e cinemática em percentuais da velocidade crítica na nata??o
Franken, Marcos;Diefenthaeler, Fernando;Carpes, Felipe Pivetta;Castro, Flávio Ant?nio de Souza;
Motriz: Revista de Educa??o Física , 2011, DOI: 10.1590/S1980-65742011000400016
Abstract: the aim of the present study was to investigate the effects of different percentages of critical speed (cs) in the heart rate (hr), the mean stroke rate (sr), the mean stroke length (sl), and perceived exertion (pe) in front crawl. fifteen swimmers of both genders performed five repetitions of 200 m at different percentages of cs (90, 95, 100, 103, and 105%), in random order. hr, pe and sr showed a significant positive correlation with the percentage of cs (rho = 0.585, p <0.001, rho = 0.720, p <0.001, rho = 0.489, p <0.001, respectively). however the sl showed no significant correlation with the percentages of cs (rho = -0.151, p> 0.05). the results from percentages of cs may help coaches to understand the impact of responses related to the internal load during training program.
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