Demodulation system Patent

Development of demodulation system for removing amplitude modulation from two quadrature displaced data bearing signal

USE OF '2D-DLT' FOR THE ANALYSIS OF LONGSWINGS ON HIGH BAR

The purpose of this study was to establish how closely a 2D DLT analysis compared with a normal 3D analysis during a longswing on the high bar. Repeated digitisations from two orthogonal camera views were averaged to produce 3D criterion data. Comparisons between 2D reconstructions from the left, right and from an additional perpendicular (2DP) camera view were made. Root mean squared differences (RMSD) for hip and shoulder angles (θH, θS) and angular velocities (ωH, ωS) were determined. Max RMSD was found to be θS= 0.06 rad viewed from the left camera and ωS = 0.60 rad.s-1 from 2DP view. It is therefore recommended that 2D DLT can be used to analyse this skill and that added accuracy can be obtained using left or right camera views during ascending and descending phases respectively. This has direct implications for future research of this type of skill

MUSCULOSKELETAL WORK PRECEDING THE TKACHEV ON UNEVEN BARS

The purpose of this study was to identify the mechanics of traditional outward facing (O) and newer inward facing (I) Tkachev on uneven bars. Images of ten straddle Tkachevs (O=5, I=5) performed at the Sydney Olympic Games, 2000 were recorded with twin video cameras (50Hz). Manual digitising and 3D DLT reconstruction techniques were combined with inertia modelling to develop customised profiles for the ten gymnasts. Inverse dynamics analyses were used to quantify hip and shoulder joint kinetics, and segmental and bar energy exchanges from the horizontal position on the downswing to bar release. There was evidence that more energy was stored in and recovered from the bar in the inward technique. The role of the hips remained similar for both skills, but a large shoulder flexion rather than extension occurred in the inward technique close to release

BIOMECHANICS AND GYMNASTICS

The applied session at the 28th The second theme presented by Dr Marianne Gittoes and Professor Peter Brüggemann examines the effects of gymnastic performance on the loading of the biological structures of the gymnast. These two talks will explore impact loading and the resultant physical demand on performers. Examples will include landing in gymnastics. One fundamental topic will be an examination of the ability of the gymnast to voluntarily i.e. consciously modify technique. Investigating what the gymnast can do and what is inherent in predisposing them to high loads therefore how does the gymnast interact technique changes with inherent mechanisms of load attenuation. International Society of Biomechanics in Sport Conference focuses on two major themes of research; the Coaching-Biomechanics Interface and Injury and biological loading. These two interrelated themes underpin the understanding and knowledge needed to provide a safe and effective environment for the development of gymnastics skills and for the well being of performers. Ecological validity permeates these research approaches ensuring that meaningful information for coaches, scientists and clinicians is provided. The four presentations will use examples from evidenced based research on these themes. Two will focus on the coaching-biomechanics interface; one from an experimental perspective (Dr Gareth Irwin) and the other from a theoretical/modelling one (Dr Mike Hiley). The coaching-biomechanics interface is a term used to conceptualise how coaching can be informed from a biomechanical perspective. The process involved here is a continuous one, with each cycle starting and ending with the athlete. The process is based on a coach’s tacit knowledge in relation to the practices that are routinely used to develop athletes’ skills. Integral to this process, is the communication between the biomechanist and the coach and athlete. This cycle of extracting, processing and imparting new scientifically grounded knowledge and understanding represents the coaching-biomechanics interface. Sometimes this new knowledge may simply reinforce existing practices or it can provide new insights which inform future skill development. The overall purpose of developing the coaching-biomechanics interface is to bridge the gap between biomechanical science and sport practice. The interface aims to make training more effective and efficient for athletes who are already working near to their physiological limits. Presenters are: 1. Dr Gareth Irwin (Wales): Coaching Biomechanics Interface: Competition and training 2. Dr Mike Hiley (England): Coaching Biomechanics Interface: Simulation modelling 3. Dr Marianne Gittoes (Wales): Variability and performance: implications for injury in gymnastics 4. Prof Dr Peter Brüggemann (Germany): Biological load and injury in gymnastic

COACHING BIOMECHANICS INTERFACE: COMPETITION AND TRAINING

Bridging the gap between the underlying biomechanical parameters that determine successful gymnastics performance, and the provision of meaningful information for coaches has been the challenge for sports biomechanists for decades. Conceptualising this fundamental relationship through the coaching-biomechanics interface draws on the cognitive processes of learning and understanding, combined with grounded scientific concepts, which help explain and increase understanding of gymnastic performance. As such the coaching-biomechanics interface begins with an examination of coaches’ implicit knowledge highlighted through the conceptual models of skill learning and development (Irwin et al., 2005). Central to this model is the development of a mind set, a conceptual understanding of how a skill works. Coaches develop an understanding of how the skill works then aim to replicate the spatial and temporal characteristics of the final skill in the physical preparations, progressions and preparatory skills used in training

KINEMATIC CHANGES DURING LEARNING THE LONGSWING ON HIGH BAR

Understanding technique development during complex skill learning provides information that can be used to influence feedback and skill development. The purpose of this study was to investigate changes in longswing technique during an 8 week period of learning. Fourteen male participants with no previous high bar experience took part in the training study. Data were collected using a CODA motion analysis system (200 Hz) during weekly testing sessions. There was a significant increase in swing amplitude for the group between week 1 and all subsequent weeks (p < .05). Based on initial swing amplitude three patterns of learning were displayed; each having distinctive functional phase characteristics. This study highlights the importance of quantifying changes in technique throughout learning on an intra-individual basis, to understand how technique changes

THE INFLUENCE OF EXPERIENCE ON FUNCTIONAL PHASE KINEMATICS OF THE LONGSWING

The biomechanics of successful longswings are well understood, however, the influence of experience on execution is not well defined. This study aims to explore functional phase (FP) kinematics during repeated longswings performed by an experienced (E), inexperienced (I) and novice (N) participant. METHODS: Three participants performed five sets of five longswings on a high bar. Data were collected using an automated motion analysis system (CODA CX-1), sampling at 200Hz. Circle angle (&#952;C) was defined by the mass centre to bar vector with respect to the horizontal. Kinematics ofFP’s, defined by maximum shoulder flexion to extension (&#952;CS) and hip extension to flexion (&#952;CH), were analysed duringswing three and four in each set

MUSCULOSKELETAL WORK IN HIGH BAR PROGRESSIONS

This study explained and assessed the similarity in joint kinetic profiles between the longswing (LS) and four progressions. Video recordings of four male gymnasts performing the LS and four progressions were quantified using 2D DLT techniques on an instrumented high bar. Inverse dynamic analyses quantified the muscle moments and work done at hips and shoulders. RMSD analysis between the work during the LS and progressions was used to group the progressions based on overall level of similarity to the LS. The least similar progression was the looped bar pendulum swing, whilst the most similar was the bent knee LS. This study has identified that progressions can be classified into those that are similar in terms of physical demand or movement pattern. This study raises the question should progressions be selected based on its kinetic or kinematic similarity to the target skill

ANGULAR MOMENTUM IN THE STRAIGHT TKATCHEV ON HIGH BAR

Angular momentum in the straddle Tkatchev was reported as part of a study by Arampatzis and Brüggemann, (2001). The Tkatchev is an interesting skill as it requires the gymnast to reverse the direction of rotation between the bar circling action (the longswing) and the flight phase from release until regrasp