Age-related differences in rapid muscle activation after rate of force development training of the elbow flexors

In young adults, improvements in the rate of force development as a result of resistance training are accompanied by increases in neural drive in the very initial phase of muscle activation. The purpose of this experiment was to determine if older adults also exhibit similar adaptations in response to rate of force development (RFD) training. Eight young (21-35 years) and eight older (60-79 years) adults were assessed during the production of maximum rapid contractions, before and after four weeks of progressive resistance training for the elbow flexors. Young and older adults exhibited significant increases (P<0.01) in peak RFD, of 25.6% and 28.6% respectively. For both groups the increase in RFD was accompanied by an increase in the root mean square (RMS) amplitude and in the rate of rise (RER) in the electromyogram (EMG) throughout the initial 100 ms of activation. For older adults, however, this training response was only apparent in the brachialis and brachioradialis muscles. This response was not observed in surface EMG recorded from the biceps brachii muscle during either RFD testing or throughout training, nor was it observed in the pronator teres muscle. The minimal adaptations observed for older adults in the bifunctional muscles biceps brachii and pronator teres are considered to indicate a compromise of the neural adaptations older adults might experience in response to resistance training.

Reducing Drifts in the Inertial Measurements of Wrist and Elbow Positions

In this paper, we present an inertial-sensor-based monitoring system for measuring the movement of human upper limbs. Two wearable inertial sensors are placed near the wrist and elbow joints, respectively. The measurement drift in segment orientation is dramatically reduced after a Kalman filter is applied to estimate inclinations using accelerations and turning rates from gyroscopes. Using premeasured lengths of the upper and lower arms, we compute the position of the wrist and elbow joints via a proposed kinematic model. Experimental results demonstrate that this new motion capture system, in comparison to an optical motion tracker, possesses an RMS position error of less than 0.009 m, with a drift of less than 0.005 ms-1 in five daily activities. In addition, the RMS angle error is less than 3??. This indicates that the proposed approach has performed well in terms of accuracy and reliability.

A numerical investigation of the flow structures and losses for turbulent flow in 90 degrees elbow bends

Computational fluid dynamic modelling was carried out on a series of pipe bends having R/r values of 1.3, 5, and 20, with the purpose of determining the accuracy of numerical models in predicting pressure loss data from which to inform one-dimensional loss models. Four separate turbulence models were studied: the standard k-epsilon model, realizable k-epsilon model, k-omega model, and a Reynolds stress model (RSM). The results are presented for each bend in the form of upstream and downstream pressure profiles, pressure distributions along the inner and outer walls, detailed pressure and velocity fields as well as overall loss values. In each case, measured data were presented to evaluate the predictive ability of each model. The RSM was found to perform the best, producing accurate pressure loss data for bends with R/r values of 5 and 20. For the tightest bend with an R/r value of 1.3, however, predictions were significantly worse due to the presence of flow separation, stronger pressure gradients, and high streamline curvature.

Day 1. Free Communications – Psychology (Session 2): The influence of body language and expected competency on gaze behaviour while forming an initial impression of a tennis player.

D1.S3.4(4). BASES Conference 2015 (Burton-on-Trent), 1-2 December. British Association of Sport and Exercise Sciences

Coping with emotional labour in tennis coaching

A tennis coach works in a social environment, employed in a service based economy with the outcome of client-customer interactions significantly impacting on the consumer experience. Research conducted outside of sport has shown that positive affective displays during interactions, which in a tennis situation may include providing support through displays of warmth, empathy, positivity and compassion as the client attempts to master a new technique, have shown positive associations with customer satisfaction. Hochschild (1983) coined the term ‘emotional labour’ to describe the process of, and demands resulting from adjusting one’s demeanour, language and tone during social encounters in a planned and strategic manner in order to facilitate a positive outcome. Hochschild proposed that individuals in jobs which require a high degree of face-to-face interaction with the public are particularly at risk of experiencing potentially deleterious effects that result from dealing with emotional labour demands on a daily basis. It would appear that tennis coaches work in environments that make them susceptible to experiencing emotional labour and as such the intention of this article is to first introduce the concept and then to provide suggestions for how a coach may cope with these demands.

Talent Identification and Development in Tennis

Accurately identifying individuals at a young age who are most likely to excel in a given sport remains a pursuit for coaches, parents and national governing bodies worldwide. In a sport such as tennis, the financial investment needed to support a player’s development is substantial, although this is offset by the vast sums of money that are on offer for those few elite players who reach the very top of the game. As such, tennis can be considered to represent a high risk, high reward venture, where the value of being able to better identify those who are likely to ‘make it’ takes on extra emphasis. The debate surrounding the timeless ‘nature versus nurture’ conundrum rumbles on and shows no sign of abating. The relative contribution that deliberate practice (Starkes & Ericsson, 2003) as opposed to genetics (Tucker & Collins, 2011) play in the development of champions remains a contentious issue. Popular texts such as ‘Bounce’ (Syed, 2010) and communications intended specifically for tennis coaches (Roetert, Kovacs & Crespo, 2009) have served to engage a wider community in the debate. It is the intention of this short article to summarize the key points emerging from this body of work and to offer some guidance to coaches moving forward.

Expectancy effects in tennis: The impact of body language and playing record on impressions of a tennis player and ratings of performance

This study examined the impact that pre-event body language and knowledge of a performer’s playing record had on ratings of tennis performance. Participants (N = 123) were allocated to one of four experimental groups (good body language/bad body language vs. positive playing record/negative playing record) and viewed a live player warming up and completing a series of tennis shots. Information outlining the player’s recent win/loss record was coupled with body language condition during a period of warm-up footage. Likert-type scales were employed to record impressions of the player and judgements as to the quality of the play. ANCOVA revealed that the player was viewed more favourably having displayed positive as opposed to negative body language (p<.001). Participants presented with a positive playing record (p = .001) formed a more favourable impression and rated the players performance more positively (p = 0.001). The study corroborates and extends the findings of recent work incorporating live models in expectancy effects investigations.

[William] Laurentz, [André] Gobert [joueurs de tennis] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 58754

Mme Pigueron [joueuse de tennis] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 58311

[Roger] Danet [et] Lefébure [joueurs de tennis] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 58312

Sabbagh [et Pierre] Hirsch [joueurs de tennis] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 58313

d'Arsonval [professeur de tennis au Sporting club de Paris] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 58314

[De gauche à droite] Lefébure, Mme Canivet, Mme Pigueron, [et Roger] Danet [joueurs et joueuses de tennis] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 58315

Mme Billout [participante au championnat du monde de tennis à Saint-Cloud] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 59416