Does breathing disturb arm to leg coordination in butterfly

International audienc

BEYOND RACE ANALYSIS

Race analysis is now well entrenched as an important part of the application of science to swimming and is keenly sought by coaches and swimmers. At present, race analysis emphasizes stroke length and stroke frequency and component times such as mid-pool (free swimming) time, turn time, and start time. A new model for identifying important variables is presented. Many of these variables are not, as yet, determined routinely. The model comprises three ‘global goals’ – the minimization of resistive impulse, the maximization of propulsive impulse, and the development of techniques that restrain physiological cost. The section of the model dealing with maximising propulsive impulse is described. Problems involved in indirectly estimating forces produced by the arm and hand are briefly addressed. It is concluded that, at this time, accurate quantification of propulsive forces by indirect means is problematic. However, it is suggested that important ‘critical features’ such as the time of ‘catch’ and ‘release’ might by estimated with reasonable accuracy provided that the effect of acceleration is taken into account. Further investigation is required to establish the accuracy and reliability of estimating these times

FROM TECHNICAL FOUNDATIONS TO INCREASED EFFICIENCY IN SWIMMING

In this presentation a model of swimming performance based on work, energy, and efficiency is introduced. Examples are provided throughout to emphasise the importance of technique in relation to energy cost and efficiency

ROCK AND ROLL RHYTHMS IN SWIMMING

This paper is based on the ISBS 2007 lecture honouring Geoffrey Dyson, a pioneer in putting sports science into practice. Although the term ‘rhythm’ is frequently used by coaches, commentators, and participants in sports, it is rarely quantified. Using examples from analysis of butterfly and front crawl swimming the lecture described how rhythms may be quantified using Fourier analysis and presented ‘typical’ results from past and current research. In combination with kinematic and kinetic data analysis of rhythms can provide an insight into what constitutes ‘good rhythm’ in specific sports skills. Importantly, there is potential to use knowledge of rhythms and their development to improve coaching practice and sports performanc

HEAD STABILIZATION IN FORWARD TWISTING SOMERSAULTS

In many acrobatic activities the rate of rotation is such that it is not possible to fix the gaze to determine one's orientation throughout the whole period of flight. With increasing head angular velocity the ability to use visual information deteriorates up to 350 degrees/s (Jell et al, 1982; Tomlinson et al, 1980). Stabilisation of the head at particular times during the flight allows visual information to be used during the performance of advanced skills involving rapid rotations. The purpose of this study was to investigate whether elite trampolinists stabilise the head during the performance of forward twisting somersaults. Two cine cameras operating at 100 frames per second recorded four elite trampolinists each performing five forward somersaults with one and one half twists (Rudi). Three dimensional analysis techniques were used to quantify the positions of head and trunk segments. The rate of rotation of the long axes (includes flexion/extension and lateral flexion/extension but not rotation about the long axis) of the head and trunk were compared to assess whether changes in rate of head rotation were associated with a strategy of head stabilisation or with rotation of the upper body. All subjects had two distinct periods of head stabilisation. The first occurred during the first half of flight at times which were consistent within subjects but variable among subjects. Minimum head angular velocity during this first period of stabilisation ranged from approximately 100 degrees/s to 250 degrees/s and was not significantly different from the angular velocity of the trunk. The second period of head stabilisation occurred consistently among subjects between 70% and 90% of the flight phase. Mean head angular velocity during this time ranged from 100 degrees/s to 250 degrees/s and was consistently less than the angular velocity of the trunk (p< .05). It was concluded that elite trampolinists stabilise the head to use visual information when preparing to land

A COST EFFECTIVE CPD PATHWAY TO BESPOKE POSTGRADUATE ACADEMIC QUALIFICATIONS FOR SPORTS PRACTITIONERS

To access higher level academic knowledge and qualifications relevant to vocational advancement, coaches and teachers of specific sports need affordable bespoke courses bridging between the courses of the coaching accreditation schemes and sport-specific postgraduate academic courses. The purpose of this project was to establish a model for delivery of on-line continuing professional development (CPD) to coaches and teachers thereby providing a pathway to higher qualifications with direct benefit to their coaching and teaching. The model includes bridging courses delivered on-line that enable participants to enter the diploma level of academic masters programmes with advanced prior learning (APL) status in lieu of the 60 credit points obtained at postgraduate certificate level. This reduces the cost of obtaining a Masters degree by one third

LIFTING PERFORMANCE IN AQUATIC SPORTS

Performance in aquatic sports is limited by the ability to maximize propulsive forces and minimize resistive forces. Propulsive forces may be generated by moving body parts or paddles in a direction opposite the direction of desired travel, that is, by using ‘drag’ forces. ‘Lift’ forces are perpendicular to the motion. Thus, if lateral motions are used, lift forces may contribute to propulsive force. Direct quantification of drag forces and lift forces in realistic settings is problematic. Therefore, scientists have relied on indirect evidence to assess the relative importance of drag forces and lift forces to propulsion in aquatic sports. The purpose of this presentation is to review the evidence relating to the use of drag forces and lift forces in three aquatic skills. These skills are freestyle swimming, flatwater kayak paddling, and the water polo ‘eggbeater’ kick. The implications for technique are discussed. Given the lack of definitive findings, the presenter seeks to stimulate further investigation into aquatic sports rather than to draw conclusions. Since the early 1970s, the view that good technique in freestyle swimming involves sculling actions of the hands to use lift forces in preference to drag forces has predominated. Recent three-dimensional studies have contradicted this view and indicate a need for further investigation. Flatwater kayak technique has changed greatly during the last 15 years following the introduction of the ‘wing’ blade. The wing blade, shaped like an airfoil to generate lift forces by the Bernoulli Principle, has resulted in improved performances. However, based on the small amount of evidence available, it is not yet clear whether lift forces contribute to propulsion more than drag forces. Some possible reasons for the improved performances in flatwater kayaking since the introduction of the wing blade are discussed. Despite its importance in water polo, the eggbeater kick has received scant attention by sports scientists. Recent indirect evidence suggests that lift forces play an important role in the eggbeater kick. It appears that players improve by modifying their motions to use lift forces in preference to drag forces

NEW RESEARCH APPROACHES ARE UNRAVELLING THE MYSTERY OF PROPULSIVE MECHANISMS IN SWIMMING

Various explanations regarding how swimmers generate propulsion have been proffered during the last half century, Investigations have been limited by the current technical 'state of the art'. The main limitations have related to the difficulty of directly measuring propulsive and resistive forces and in observing the behaviour of the fluid. The purpose of this presentation is to provide an historical account of how developing methods of analysis are enabling us to unravel the mystery of propulsion in swimming

HOW IS SCIENTIFIC SPORT RESEARCH BEING DISSEMINATED TO COACHES?

The main purpose of this study was to find out how sports scientists are disseminating research findings to sport coaches as a first step towards developing better ways of disseminating information in a ‘coach friendly’ manner. It was deemed important to obtain the perspectives of both sport scientists and coaches and also to investigate the role of emerging techniques of dissemination including the World Wide Web. The use of the World Wide Web was of specific interest since these electronic tools provide search and retrieval abilities beyond anything that can be done with paper, even the best papers are of no use if they can not be located. (Boyce P.B. & Dalterio H. 1996)