Gamma Group-The Pale Horse: A proposal in response to a commercial air transportation study ort study

A conventional remotely piloted vehicle (RPV) was designed to operate in a fictional 'Aeroworld' as a 30 passenger aircraft. The topics addressed include: economic/cost analysis, aerodynamics, weight and structures, propulsion, stability and control, and performance

Changes in joint kinetics during learning the longswing on high bar

Biomechanics helps us understand the association between technique changes and performance improvement during learning. The aim of this research was to investigate joint kinetic characteristics of technique during learning of the longswing on the high bar. Twelve male, novice participants took part in the learning study. During swing attempts in 8 weekly testing sessions, kinematic data were collected. Inverse dynamics analysis was performed from known zero forces at the toes to quantify joint moments and power at the hips and shoulders. Key biomechanical constraints that limited performance outcome were identified based on changes in joint kinetics during learning. These constraints were the ability to perform a large shoulder power and to overcome passive kinetics acting during the downswing. Constraints to action at the level of joint kinetics differentially challenge learners and therefore could underpin more individual, specific learning interventions. Functional phases, defined by maximum hyperextension to flexion of the hips and maximum flexion to extension of the shoulders, did not describe the key joint kinetics of the hip and shoulder for novices. The functional phases may serve however to identify novices that were unable to overcome the passive kinetic constraint

Multidimensional joint coupling: a case study visualisation approach to movement coordination and variability

A case study visualisation approach to examining the coordination and variability of multiple interacting segments is presented using a whole-body gymnastic skill as the task example. One elite male gymnast performed 10 trials of 10 longswings whilst three-dimensional locations of joint centres were tracked using a motion analysis system. Segment angles were used to define coupling between the arms and trunk, trunk and thighs and thighs and shanks. Rectified continuous relative phase profiles for each interacting couple for 80 longswings were produced. Graphical representations of coordination couplings are presented that include the traditional single coupling, followed by the relational dynamics of two couplings and finally three couplings simultaneously plotted. This method highlights the power of visualisation of movement dynamics and identifies properties of the global interacting segmental couplings that a more formal analysis may not reveal. Visualisation precedes and informs the appropriate qualitative and quantitative analysis of the dynamics

Biomechanical energetic analysis of technique during learning the longswing on high bar

Biomechanical energetic analysis of technique can be performed to identify limits or constraints to performance outcome at the level of joint work, and to assess the mechanical efficiency of techniques. The aim of this study was to investigate the biomechanical energetic processes during learning the longswing on the high bar. Twelve male, novice participants took part in a training study. Kinematic and kinetics data were collected during swing attempts in eight weekly testing sessions. Inverse dynamics analysis was performed from known zero forces at the toes. Joint work, total energy, and bar energy were calculated. Biomechanical constraints to action, that is, limits to novice performance, were identified as “total work” and “shoulder work”. The most biomechanically efficient technique was associated with an onset of the hip functional phase and joint work that occurred between 10–45° before the bottom of the swing. The learning of gross motor skills is realised through the establishment of a set of techniques with task specific biomechanical constraints. Knowledge of the biomechanical constraints to action associated with more effective and efficient techniques will be useful for both assessing learning and establishing effective learning interventions

Mudança em aprendizagem motora: Uma perspectiva de Coordenação e Controle

This paper examines the issue of change in motor learning from a dynamical systems framework. There is qualitative and quantitative change to performance over time that is driven by an embedded set of evolving dynamical systems each with its own time scale of change. Learning arises through searching and the evolution and dissolution of the stable dynamical regions of coordination modes for a given task. Learning then is discovering (searching for) the dynamic laws. The nature of the relevant of information that facilitates the search and the transitions of the stable modes of performance is the key to the efficacy of learning strategies.Este trabalho examina a questão relativa a mudanças em aprendizagem motora a partir do esquema de referência dos sistemas dinâmicos. Existe mudança qualitativa e quantitativa no desempenho ao longo do tempo que é resultado de um conjunto intrincado de sistemas dinâmicos em evolução, cada um em sua própria escala de tempo de mudança. A aprendizagem ocorre através da busca e da evolução e dissolução de regiões dinâmicas estáveis dos modos de coordenação para uma dada tarefa motora. Assim, o aprendizado é a descoberta (busca) de leis dinâmicas. A natureza das informações relevantes que facilitam a busca e as transições de modos estáveis de performance é a chave para a eficácia de estratégias de aprendizagem

Coordination changes in the early stages of learning to cascade juggle

The experiment was setup to examine the coordination changes in assembling the movement form of 3-ball cascade juggling. Eight adult participants learned to juggle over 4 weeks of practice. Juggling scores were recorded at each session and performance was videotaped at eight selected sessions for purposes of movement analysis. Once the basic spatial and temporal constraints on cascade juggling were satisfied, and the figure-8 juggling mode was established, temporal modulations of the relative motions of the hands were emphasized. All participants learned to juggle and the increase over practice in the number of consecutive balls caught was best fit with a power law. The non-proportional rate of performance increment was consistent with the qualitative changes in the form of the hand and ball movement kinematics that occurred over practice

ACCURACY OF BODY MASS PREDICTION USING SEGMENTAL INERTIA PARAMETERS MODELLED FROM PHOTOGRAPHIC IMAGES

The aim of this study was to evaluate the accuracy between the measured and predicted body mass, using the methods of Gittoes et al. (2009), and investigate the relationship between mass and stature and this accuracy. Fifteen male, recreational athletes from a university’s sporting population took part in the study. Measured whole-body masses were compared with predicted whole-body masses calculated using photographic dimensional data and an inertia model. Mean absolute error between measured and predicted whole-body mass was 5.42 ± 2.92 %. A strong, negative correlation between measured whole-body mass and relative % error (r = -0.80) and a normalising value and relative % error was found. It is suggested that for similar participants errors could be up to ± 10% for participants with body masses much greater or less than 71 kg or normalising values equating to 1230 Nm

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

THE INFLUENCE OF EXPERIENCE ON KINETIC CHARACTERISTICS OF THE LOOPED LONGSWING

The aim of this study was to increase understanding of the strategies performers use to complete the looped longswing (LLS) in order to provide useful information for the development of this skill. For an elite gymnast and two novice performers, kinematic and kinetic data were collected during 5 series of three LLS (CODA motion analysis system, 200 Hz; instrumented high bar, 1 kHz). Inverse dynamics were employed to determine joint kinetics during the second LLS in each trial for each performer. The elite gymnast performed positive work at the hips during the ownswing resulting in hip flexion, which facilitated the control of proceeding functional phase actions. Peak shoulder power values were highest for the elite gymnast and lowest for the least experienced novice participant

Coordination as a function of skill level in the gymnastics longswing

The purpose of this study was to investigate the nature of inter-joint coordination at different levels of skilled performance to: (1) distinguish learners who were successful versus unsuccessful in terms of their task performance; (2) investigate the pathways of change during the learning of a new coordination pattern and (3) examine how the learner’s coordination patterns relate to those of experts in the longswing gymnastics skill. Continuous relative phase of hip and shoulder joint motions was examined for longswings performed by two groups of novices, successful (n = 4) and unsuccessful (n = 4) over five practice sessions, and two expert gymnasts. Principal component analysis showed that during longswing positions where least continuous relative phase variability occurred for expert gymnasts, high variability distinguished the successful from the unsuccessful novice group. Continuous relative phase profiles of successful novices became more out-of-phase over practice and less similar to the closely in-phase coupling of the expert gymnasts. Collectively, the findings support the proposition that at the level in inter-joint coordination a technique emerges that facilitates successful performance but is not more like an expert’s movement coordination. This finding questions the appropriateness of inferring development towards a “gold champion” movement coordination