Grip and load force coordination in cyclical isometric manipulation task is not affected by the feedback type

Background: The relationship between normal and tangential force components (grip force - GF and load force - LF, respectively) acting on the digits-object interface during object manipulation reveals neural mechanisms involved in movement control. Here, we examined whether the feedback type provided to the participants during exertion of LF would influence GF-LF coordination and task performance. Methods. Sixteen young (24.7 ±3.8 years-old) volunteers isometrically exerted continuously sinusoidal FZ (vertical component of LF) by pulling a fixed instrumented handle up and relaxing under two feedback conditions: targeting and tracking. In targeting condition, FZ exertion range was determined by horizontal lines representing the upper (10 N) and lower (1 N) targets, with frequency (0.77 or 1.53 Hz) dictated by a metronome. In tracking condition, a sinusoidal template set at similar frequencies and range was presented and should be superposed by the participants' exerted FZ. Task performance was assessed by absolute errors at peaks (AEPeak) and valleys (AEValley) and GF-LF coordination by GF-LF ratios, maximum cross-correlation coefficients (r max), and time lags. Results: The results revealed no effect of feedback and no feedback by frequency interaction on any variable. AE Peak and GF-LF ratio were higher and rmax lower at 1.53 Hz than at 0.77 Hz. Conclusion: These findings indicate that the type of feedback does not influence task performance and GF-LF coordination. Therefore, we recommend the use of tracking tasks when assessing GF-LF coordination during isometric LF exertion in externally fixed instrumented handles because they are easier to understand and provide additional indices (e.g., RMSE) of voluntary force control. © 2013 Pedão et al.; licensee BioMed Central Ltd.

The physiological demands of table tennis: A review

Although table tennis has a tradition lasting more than 100 years, relatively little is known about players' physiological requirements - especially during competition. In this review we discuss research studies that have led to our current understanding of how the body functions during table tennis training and competition and how this is altered by training. Match and practice analysis of the table tennis game indicates that during intense practice and competition it is predominantly the anaerobic alactic system that is called into play, while the endurance system is relied on to recovery the anaerobic stores used during such effort. It is thus important for coaches to keep in mind that, while the anaerobic alactic system is the most energetic system used during periods of exertion in a table tennis game, a strong capacity for endurance is what helps a player recover quicker for the following match and the next day of competition. This paper provides a review of specific studies that relate to competitive table tennis, and highlights the need for training and research programs tailored to table tennis. © Journal of Sports Science and Medicine.

Influência da seleção dos estágios incrementais sobre a intensidade de lactato mínimo: Estudo piloto

The purposes of this study were to assess the influence of stage selection from the incremental phase and the use of peak lactate after hyperlactatemia induction on the determination of the lactate minimum intensity (iLACmin). Twelve moderately active university students (23±5 years, 78.3±14.1 kg, 175.3±5.1 cm) performed a maximal incremental test to determine the respiratory compensation point (RCP) (initial intensity at 70 W and increments of 17.5 W every 2 minutes) and a lactate minimum test (induction with the Wingate test, the incremental test started at 30 W below RCP with increments of 10 W every 3 minutes) on a cycle ergometer. The iLACmin was determined using second order polynomial adjustment applying five exercise stage selection: 1) using all stages (iLACmin P); 2) using all stages below and two stages above iLACminP(iLACminA); 3) using two stages below and all stages above iLACminP(iLACminB); 4) using the largest and same possible number of stages below and above the iLACminP(iLACminI); 5) using all stages and peak lactate after hyperlactatemia induction (iLACminD). No differences were found between the iLACminP(138.2±30.2 W), iLACminA(139.1±29.1 W), iLACminB(135.3±14.2 W), iLACminI(138.6±20.5 W) and iLACmiD(136.7±28.5 W) protocols, and a high level of agreement between these intensities and iLACminPwas observed. Oxygen uptake, heart rate, rating of perceived exertion and lactate corresponding to these intensities was not different and was strongly correlated. However, the iLACminBpresented the lowest success rate (66.7%). In conclusion, stage selection did not influence the determination of iLACmin but modified the success rate. © Creative Commom.

Energy expenditure during multiple sets of leg press and bench press

The purpose of this study was to quantify energy expenditure (EE) during multiple sets of leg press (LP) and bench press (BP) exercises in 10 males with at least 1 yr of resistance training (RT). The subjects underwent two sessions to determine 1 repetition maximum (1RM) on the BP and LP and one protocol consisting of a warm up and 4 sets for 10 repetitions at 70% 1RM with a 3-min rest period between sets for each exercise. Energy expenditure was calculated as the sum of oxygen uptake (aerobic component), EPOC, and lactate production (anaerobic component). There were no significant differences in EE between exercises for sets 1 to 4 and the total energy expended. However, statistical analysis revealed a significant difference (P<0.05) between exercises in RT economy (BP, 0.0206 ± 0.0044 kcal·kg-1 vs. LP, 0.0051 ± 0.0015 kcal·kg-1). Within exercise comparison showed set 4 was significantly different from sets 1 and 3 for BP, and for LP a significant difference was found between set 4 and sets 1, 2 and 3. Our results point to an increase in EE during multiple sets at 70% 1RM and show that in spite of the difference in muscle mass involved and total work done during each type of exercise, EE was not different due to greater economy during the LP.

Influência da música no estado de ânimo e no desempenho em exercícios

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A eletromiografia em treinamento resistido: avaliação da fadiga muscular, adaptações e relações com parâmetros subjetivos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Respostas hormonais e metabólicas durante sessão de exercício resistido

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Associações entre, índices fisiológicos e fadiga neuromuscular com padrões de deslocamento e desempenho do chute de finalização no futsal

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evolução de pacientes portadores de peumopatias crônicas e hipoxemia transitória ao esforço tratados com oxigenoterapia domiciliar prolongada durante o sono e ao esforço

Pós-graduação em Fisiopatologia em Clínica Médica - FMB

Respostas fisiológicas, bioquímicas e autonômicas de nadadores submetidos a dois modelos de treinamentos em nado atado com carga equiparada

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Monitoring muscle damage markers during a four-week downhill walking exercise program

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito das cargas de treinamento sobre parâmetros fisiológicos de futebolistas

The aim of this study was to investigate the effects of three weeks of training with intensity monitored on the aerobic capacity of professional soccer players. Fourteen players, members of a first division Brazilian Championship team in 2010, aged 22.78 +/- 3.06 years were evaluated pre and post three weeks of training. The anaerobic threshold intensity LAn was determined by bi-segmented method, for this four submaximal efforts of 800 meters with intensities 10, 12, 14 and 16 km/h were applied. Thirty three training sessions were quantified in zones according to heart rate related to the LAn (FCLAn): Z1 - 10% below, Z2 - 90-100% and Z3 - above the FCLAn. During training participants remained 31.17 +/- 14.86%, 42.96% and 25.87 +/- 14.90 +/- 16.67% in Z1, Z2, and Z3 respectively. There were no significant differences in the LAn (pre = 13,29 +/- 0,71 km.h(-1); post = 12,85 +/- 0,90 km.h(-1)), perceived exertion (pre = 11,53 +/- 1,45 u.a; post = 11,23 +/- 1,53 u.a) and FCLAn (pre = 166,64 +/- 10,69 bpm; post = 174,50 +/- 10,89 bpm) between conditions before and after training, indicating that three weeks of training are insufficient to generate positive changes in soccer players LAn.

Validação de uma escala colorida de esforço percebido para adultas jovens e idosas em caminhada na esteira

The perceived exertion has been used for the intensity control and exercise prescription. Among the various scales that estimate the perceived exertion, the Borg’s RPE scale is one of the best known. However, for populations with low levels of schooling or with visual difficulties such as the elderly, the application of these scales becomes more difficult. In previous studies, a color scale of perceived exertion was developed to aim for assistance in application of the scale and interpretation of perceived exertion. This scale showed high correlation with the Borg’s scale and proved to be valid to estimate the perceived exertion. Thereby, the aim of this study was to assess the validity of the color scale of perceived exertion to measure the perceived exertion in adult women of different ages. Participated in the study 12 young adult women with age of 21,7 ± 1,5 years old, and 10 elderly women with age of 60,3 ± 3,5 years old. The participants were submitted to an incremental exercise of treadmill walking with stages of 2 minutes duration. The inicial load was 5,5 km/h and inclination of 6% for young women and 2% for elderly women, both with 2% increments at each stage completed, without changing the speed. Heart rate and oxygen comsuption responses were determined at the 30 finals seconds of each stage. At the 60 finals seconds of each stage participants indicated the perceived exertion for the overall body, for the legs and for the chest, primarily in the color scale and following in the tradicional Borg’s scale. The analysis of variance for repeated measures was used to assess the effect of different loads on the perceived exertion and physiological responses. The correlations betwen physiological variables, color scale and Borg’s scale were analyzed in group and individually. In all analysis the significance...(Complete abstract click electronic access below)

Efeito da manipulação do feedback da percepção subjetiva de esforço esperada na percepção subjetiva de esforço e no desempenho de adultos de diferentes faixas etárias

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

O nível de esforço físico durante o treinamento coletivo no Futsal na categoria Sub 13

Futsal is one of the most popular sports in Brazil, played on five continents, in hundreds of countries, but is still a poorly studied sports science. Among the types of training used in the preparation of soccer players, the collective training is one of the most used because it is a simulation game. The application of the training load is often made in large quantities (volume) with exercise duration and intensity greater than what the athlete can handle. Thus, this study aimed to evaluate the intensity of physical exertion of futsal players of basic category during collective training. We evaluated twenty (N=20) soccer players from two teams with different levels of training. There were ten players on a team federated (FED) and ten players on a team for a project extension (EXT). Samples were collected at the respective locations of training. An evaluation of anthropometric and during collective training heart rate was measured and at the end of each training time blood samples were collected for analysis of blood lactate concentration and perceived exertion of the players. There was significant difference between the two teams only in fat percentage (FED=13,4 e EXT=21,2). The average heart rate during training was 174 ± 12.2 bpm, which corresponds to 84% HRmax. There was significant difference between heart rate and the percentage of HRmax in the two parts of training in both teams. The Federated team players remained most of the time in more intense intensity zone (above 85% HRmax), while the EXT players were most of the time zone of moderate intensity (65-85% HRmax). The rating of perceived exertion (FED=3,5 e EXT=3,2) and blood lactate concentration (FED=2.4 mmol/L and EXT=2.9 mmol/L) showed no significant difference between the two teams and between the two times. During training there was a significant correlation (p= 0.71) between heart rate and lactate concentration. The collective training showed an intensity that is supposed to be...