A Java Framework for Data Sonification and 3D Graphic Rendering

(Abstract to follow

CROSS RECURRENCE QUANTIFICATION ANALYSIS OF INTER-LEG RELATIONS ACROSS THE GAIT TRANSITION

The aim of this study was to quantify characteristics of the deterministic properties of inter-leg movements over the gait transition. The purpose was to further understanding of the nonlinear characteristics of the gait of a healthy individual. A participant locomoted on a treadmill as the speed steadily increased from 0 to 18 km/h over a 120 s period. Position of the approximate center of rotation of the bilateral toe, ankle, knee and hip, were collected (CODAmotion; 100 Hz). The mathematical addition of the four markers representing the “free leg” in the direction of travel (x direction) provided the variables “left leg” and “right leg”. Each leg was embedded with a dimension of 3 and time lag of 18 points to create the Taken’s vector. Cross Recurrent Quantification Analysis (RQA) was then performed. Two distinct phases in the combined dynamics of the leg-leg system were observed, with lower determinism in the walking phase compared to running, separated by a clear, sharp transition. Results indicate that determinism in the cross dynamics of the two legs seems to play a role similar to an order parameter for the walk-run phase transition. This work increases our understanding of the nonlinear dynamics characteristics of the gait transition

LIMIT CYCLE REPRESENTATION OF THE GYMNASTICS LONGSWING

Human movement science is searching for ways to capture global dynamics of our complex multi-segment system. The aim of this study was to explore differences in a limit cycle representation of longswings on high bar as a function of skill level. One elite international, one collegiate, and one novice gymnast performed four consecutive longswings on high bar. Through the novel representation of the longswing as a limit cycle, and exploration of the limit cycle characteristics, it is shown that higher frequency, more phase coherent oscillations, and lower limit cycle variability occurs as a function of skill level. It is suggested that this candidate collective variable be explored as a global indicator of skill level and learning that can provide insight into the efficiency of the mechanical system

DYNAMICS OF HANDSTAND BALANCE

The purpose of this study was to identify parameters that are associated with more successful motor control during handstand performance. For two groups of gymnasts, ‘less skilled’, who were able to hold handstands for 4 to 6s, and ‘more skilled’, who held handstands in excess of 10s, centre of mass (CoM) and centre of pressure (CoP) motion during the initial 3s of the handstand stability phase were analysed, as well as the 6 to 9s stabilised period for the more skilled gymnasts (balance phase). Time-space, time-frequency, CoM-CoP coherence, Hurst Exponent and CoM-CoP causality were investigated in anterior-posterior (AP) and medio-lateral (ML) directions. Characteristics of CoM and CoP for more and less skilled gymnasts were found to be directionally dependent (AP and ML). Nonlinear and frequency domain measures distinguished skill levels to a greater extent than time-space domain measures. The study findings shed light on the subtleties and complexities of the mechanics and dynamics that define CoM and CoP relations with increased skill level, that add to both basic and applied understanding

Coordination in gait: Demonstration of a spectral approach

Many important notions in Life Sciences are linked with the idea of cycles, periodicity, fluctuations and transitions. The aim of this paper is to use spectral analysis in a unique way to study and quantify whole body coordination during gait. A participant walked at 3 km/h and ran at 15 km/h on a treadmill for 2 minutes. Position of the approximate center of rotation of the toe, ankle, knee, hip, shoulder, elbow and wrist, and heel, PSIS and head were collected at 100 Hz using CODAmotion analysis system. Fast Fourier Transform was performed on x-coordinate data of the 1) knee marker; 2) 4 markers attached to the free lower limb (toe, ankle, heel and knee); 3) left and right free lower limbs; 4) whole body (all markers). Gait is described by a largely harmonic and resonant oscillator that operates unilateral free limbs at the stride frequency, and axial regions at the step frequency. Running is described by a more harmonic and resonant oscillating structure than walking, with a 3 times higher Q factor and 47% lower Inharmonicity Index. This method is presented as a way to capture global dynamics of our complex multi-segment system, and presents a novel application of spectral analysis to study coordination in multiple oscillators

INFLUENCE OF CALCULATION PARAMETERS ON NONLINEAR DYNAMICS MEASURES

Nonlinear analysis methods based on a dynamical systems approach have become more prevalent in recent biomechanics studies. The aim of this study is to identify the range of time delay and embedding dimension values estimated for gait data, and how sensitive Lyapunov exponent and correlation dimension are to the range of these values. A participant walked at 3 km/h and ran at 9 km/h on a treadmill for 2 minutes. Lyaponuv exponent and correlation dimension were calculated based on a combination of the optimal and mean average time delay (TD) and embedding dimension (ED) for both angle and marker data. In the majority of literature, only one ED and TD is considered for LyE estimation, based on an average across data or values suggested in previous papers. However, the results of our study show that every angle or position, has an optimum ED and TD, and the use of these values affects the nonlinear dynamics values in non-trivial ways

LIMIT CYCLE DYNAMICS ACROSS ELITE MALE ARTISTIC GYMNASTS

Biological systems described by their attractor dynamics provide a method to understand the fundamental characteristics of skilled movement. Here the limit cycle dynamics of the longswing were investigated across tiers of elite men’s gymnasts. Senior, junior and development elite gymnasts (N=21) performed three trials of eight consecutive longswings on high bar. Limit cycle analysis revealed a more symmetrical angular velocity of the centre of mass about the bar trajectory in phase space, higher recurrence, lower correlation dimension and lower variability for senior gymnasts suggesting a more deterministic, efficient and predictive technique. The addition of non-linear dynamics to traditional biomechanics offers complementary theoretical and coaching knowledge to movement coordination, control and skill

Data sonification of volcano seismograms and Sound/Timbre reconstruction of ancient musical instruments with Grid infrastructures

n/

DYNAMICS OF A CYCLIC TASK BEFORE AND AFTER A CHANGE IN TASK CONSTRAINT: HORIZONTAL BAR LONGSWING

Returning to a consistent technique after a change in skill allows gymnasts to improve routine fluidity. This study investigates the limit cycle dynamics of the mass centre (CM) after a variation in task constraint during the horizontal bar longswing (LS). Gymnasts (n=12) from 3 different age categories completed 3 x 8 consecutive LS with LS four and five as accelerated LS. Senior gymnasts presented the most consistent limit cycle trajectory and lowest correlation dimension (CD) post- compared to pre- task constraint. Senior gymnasts displayed significantly lower CD post- constraint compared to both junior (p = .016) and development gymnasts (p\u3c .001). The increased proficiency attributed to senior gymnasts appears to increase the stability features of the LS limit cycle of the CM angular velocity after an imposed task constraint which may indicate readiness to progress to more complex horizontal bar skills