Abstracts

 1. Automated Inertial Feedback For Half-Pipe Snowboard Competition And The Community Perception 

Harding JW, Toohey K, Martin DT, Mackintosh CG, Lindh AM, James DA. (2007) Automated Inertial Feedback For Half-Pipe Snowboard Competition And The Community Perception. In The Impact of Technology on Sport II, Fuss F. K., Subic A., Ujihashi S. Taylor & Francis London., 20, 845 – 850. 

No scientific research has yet targeted the athletic performance aspects or subjective judging protocols associated with elite half-pipe snowboard competition.  Recently however, sport scientists from the Australian Institute of Sport (AIS) initiated a video based analysis of key performance variables (KPVs) associated with elite half-pipe snowboard competition. The development of a preliminary automated feedback system based upon Micro-electrochemical Systems (MEMS) sensors such as tri-axial accelerometers and tri-axial rate gyroscopes, designed to calculate objective information on these sport specific KPVs was initiated in parallel.  Although preliminary, the results may provide practical benefit for elite half-pipe snowboard training and current subjective judging protocols. In light of theorised implications, this paper investigated the perception and possible social impact of these concepts on the practice community. Data was collected via semi-structured, open ended interviews with nine subjects (six athletes, two coaches, and one judge) currently involved in elite half-pipe snowboard competition. This study revealed 6 dimensions and 20 sub-dimensions relating to the practice community’s perceptions of 3 major themes that emerged during interviews. The themes included: 1) State of the current subjective judging system, 2) Automated feedback and objective judging system, and 3) Future direction of the sport. There was dominant negative perception of a proposed automated judging concept based solely on objective information unless the system integrates with the current subjective judging protocol and continues to allow athletic freedom of expression and the capacity for athletes to showcase individual style and flair in elite competition. The results of this study provide the practice community an initial public forum to describe its perceptions to future automated judging concepts, nominating them to be the primary determinants of change, technological or otherwise, within their sporting discipline.  Read Full Paper … 

 2. Feature Extraction of Performance Variables in Elite Half-Pipe Snowboarding Using Body Mounted Inertial Sensors  

Harding JW, Small JW, James DA. (2007) Feature Extraction of Performance Variables in Elite Half-Pipe Snowboarding Using Body Mounted Inertial Sensors. In BioMEMS and Nanotechnology III, edited by Dan V. Nicolau, Derek Abbott, Kourosh Kalantar-Zadeh, Tiziana Di Matteo, Sergey M. Bezrukov, Proceedings of SPIE Vol. 6799 (SPIE, Bellingham, WA, 2007) 679917. 

Recent analysis of elite-level half-pipe snowboard competition has revealed a number of sport specific key performance variables (KPV’s) that correlate well to score1. Information on these variables is difficult to acquire and analyse, relying on collection and labour intensive manual post processing of video data. This paper presents the use of inertial sensors as a user-friendly alternative and subsequently implements signal processing routines to ultimately provide automated, sport specific feedback to coaches and athletes. The author has recently shown that the key performance variables (KPV’s) of total air-time (TAT) and average degree of rotation (ADR) achieved during elite half-pipe snowboarding competition show strong correlation with an athlete’s subjectively judged score. Utilising Micro-Electrochemical System (MEMS) sensors (tri-axial accelerometers) this paper demonstrates that air-time (AT) achieved during half-pipe snowboarding can be detected and calculated accurately using basic signal processing techniques. Characterisation of the variations in aerial acrobatic manoeuvres and the associated calculation of exact degree of rotation (DR) achieved is a likely extension of this research. The technique developed used a two-pass method to detect locations of half-pipe snowboard runs using power density in the frequency domain and subsequently utilises a threshold based search algorithm in the time domain to calculate air-times associated with individual aerial acrobatic manoeuvres. This technique correctly identified the air-times of 100 percent of aerial acrobatic manoeuvres within each half-pipe snowboarding run (n = 92 aerial acrobatic manoeuvres from 4 subjects) and displayed a very strong correlation with a video based reference standard for air-time calculation (r = 0.78 ± 0.08; p value < 0.001; SEE = 0.08 ×/÷ 1.16; mean bias = -0.03 ± 0.02s) (value ± or ×/÷ 95% CL).  Read Full Paper …

3.  Classification of Aerial Acrobatics in Elite Half-Pipe Snowboarding Using Body Mounted Inertial Sensors.  

Harding JW, Mackintosh CG, Hahn AG, James DA. (2008) Classification of Aerial Acrobatics in Elite Half-Pipe Snowboarding Using Body Mounted Inertial Sensors. In The Engineering of Sport 7, Estivalet, M., Brisson, P. Springer-Verlag France., Vol. 2, 447 – 456. 

We have previously presented data indicating that the two most important objective performance variables in elite half-pipe snowboarding competition are air-time and degree of rotation. Furthermore, we have documented that air-time can be accurately quantified by signal processing of tri-axial accelerometer data obtained from body mounted inertial sensors. This paper adds to our initial findings by describing how body mounted inertial sensors (specifically tri-axial rate gyroscopes) and basic signal processing can be used to automatically classify aerial acrobatic manoeuvres into four rotational groups (180, 360, 540 or 720 degree rotations). Classification of aerial acrobatics is achieved using integration by summation. Angular velocity (ωi, j, k) quantified by tri-axial rate gyroscopes was integrated over time (t = 0.01s) to provide angular displacements (θi, j, k) at ith sample points. Absolute angular displacements for each orthogonal axes (i, j, k) were then accumulated over the duration of an aerial acrobatic manoeuvre to provide the total angular displacement achieved in each axis over that time period. The total angular displacements associated with each orthogonal axes were then summed to calculate a composite rotational parameter called Air Angle (AA). We observed a statistically significant difference between AA across four half-pipe snowboarding acrobatic groups which involved increasing levels of rotational complexity (P = 0.000, n = 216). The signal processing technique documented in this paper provides sensitive automatic classification of aerial acrobatics into terminology used by the snowboarding community and subsequently has the potential to allow coaches and judges to focus on the more subjective and stylistic aspects of half-pipe snowboarding during either training or elite-level competition.  Read Full Paper …

 4.  Technology and Half-Pipe Snowboard Competition – Insight From Elite-Level Judges 

Harding JW, Toohey K, Martin DT, Hahn AG, James DA. (2008) Technology and Half-Pipe Snowboard Competition – Insight From Elite-Level Judges. In The Engineering of Sport 7, Estivalet, M., Brisson, P. Springer-Verlag France., Vol. 2, 467 – 476. 

Automated objective information specific to half-pipe snowboarding has now been made available with micro-technology and signal processing techniques. In consultation with the practice community this has been introduced into training and competition in Australia. It is understood that any integration of technology into elite sport can effect change beyond the original purpose and can often generate unintended consequences. We have therefore evaluated the perceptions of key members of the elite half-pipe snowboard community in regards to how emerging technology could interface with the sport. Data were collected via semi-structured, open ended interviews with 16 international, elite-level half-pipe snowboard competition judges. This study revealed 8 dimensions and 42 sub-dimensions related to the community’s perceptions to 5 major themes that emerged during interviews. The major themes included: 1. Snowboarding’s Underlying Cultural Ethos 2. Snowboarding’s Underlying Self-Annihilating Teleology 3. Technological Objectivity 4. Concept Management 5. Coveted Future Directions. There was dominant perception that an underlying self-annihilating teleology could exist within competitive half-pipe snowboarding. This was believed however to pose a distant threat on judging protocols to reliably assess performance. Judges sampled in this study were largely in favour of using automated objectivity to enhance the judging process however, with a number of caveats. Most importantly that objective information is to be used as a judging aid and not for automatic generation of scores. This would address the most prevalent concern that integrating any automated objectivity into snowboarding could potentially remove freedom of expression and the opportunity to showcase athletic individuality – traits valued by the practice community. Our data highlight that successful implementation of emerging technologies in sport will be not be based on the type of technology developed but instead by the integration process which must feature a large element of control imparted to the key players within the sport.  Read Full Paper …

5.  Automated Scoring for Elite Half-Pipe Snowboard Competition – Important Sporting Development or Techno Distraction?  

Harding JW, Mackintosh CG, Martin DT, Hahn AG, James DA.  Automated Scoring for Elite Half-PIpe Snowboard Competition – Important Sporting Development or Techno Distraction?  Sports Technology 2008; 1 (6), 277 – 290. 

The authors have previously reported a strong relationship between video based objective data (air-time and degree of rotation) and subjectively judged scores awarded during elite half-pipe snowboard competition.  Advancements in sports monitoring technologies now provide the capacity to accurately and automatically quantify this objective information. This may assist current subjective coaching and competition judging protocols provided the integration process imparts a large element of control to key players within the sport.  The authors therefore recently hosted an invitational half-pipe snowboard competition (2007 Australian Institute of Sport (AIS) Micro-Tech Pipe Challenge) designed to evaluate whether the snowboard community would embrace a competition where results were in part determined by automated objectivity, explore the practical, logistical and technical challenges associated with conducting such an event and evaluate the relationship between subjective judging and results predicted from objective information to see if prior research had ecological validity.  Ten elite male half-pipe snowboarders were instrumented with inertial sensors throughout this competition.  A prediction equation using previously established weightings of average air-time and average degree of rotation accounted for 74% of the shared variance in subjectively judged scores awarded during this competition.  Although our predictions of overall scores and rankings were good there was still 26% of the total variance unexplained.  This should not be considered a weakness of this approach but a strength as the subjective components of style and execution should never be removed from the sport.  The future of half-pipe snowboarding however may be best guided a judging protocol that incorporates both objective and subjective criteria.  Read Full Paper …

6.  Fusion of Technological Objectivity into the Underlying Anarchy of Elite Snowboarding - Insights from the Australian National Snowboard Coach.  

Harding JW, James DA. Fusion of Technological Objectivity into the Underlying Anarchy of Elite Snowboarding - Insights from the Australian National Snowboard Coach. Sports Technology 2008; 1 (6), 239 – 248. 

This interview was focussed upon gaining practice community insight into the potential of micro-technology and subsequent automated objectivity to assist coaches and competition judges with performance assessment during elite half-pipe snowboarding. The sport of half-pipe snowboarding has however traditionally assessed performance during training, free riding and competition by purely subjective measures and until recently has had very little to do with sport science and the focus of objectifying performance parameters associated with rigorous scientific inquiry.  The authors have previously shown there is a strong relationship between objective key performance variables such as air-time and degree of rotation (assessed using video based analysis) and an athletes’ subjectively judged score during elite half-pipe snowboarding competitions. Video based analysis however requires labour intensive manual post processing of data and is associated with a large time delay in information feedback.  As such it is theorised to have limited potential for the feedback of objective information to snowboard athletes, coaches, and judges.  The authors have therefore worked alongside numerous collaborators from the Australian Institute of Sport (AIS), the Olympic Winter Institute of Australia (OWIA), Griffith University (GU) and Catapult Innovations to develop a system of automated objectivity based on tri-axial accelerometers and tri-axial rate gyroscopes that can calculate air-time and degree of rotation during half-pipe snowboard runs.  The concept was originally focussed on enhancing current training protocols but has also shown potential to support judges in assessing athletic performance during elite half-pipe snowboard competition.  Although there is a potential benefit to using systems of automated objectivity within the sport of snowboarding there are also potential drawbacks associated with objectifying a sport that prides itself on providing a platform that allows freedom of expression and the capacity to showcase athletic individuality.  It is believed that the integration of any form of objectivity into a sport such as half-pipe snowboarding should be conducted whilst allowing key practice community members control over the overall direction.  This 45-minute interview was conducted by Jason Harding (AIS sport scientist) with Ben Wordsworth (the Australian national snowboard coach currently affiliated with the Olympic Winter Institute of Australia) in between surfs at Manly Beach NSW Australia on Wednesday 1st October 2008.  Read Full Paper …

7.  The Ben Mates Interview. 

Harding JW. (2010).  The Ben Mates Interview. Images: Fawcett, A., Weyerhaeuser, M., Laurila, C.  (2010).  The Ben Mates Interview.  www.AnarchistAthlete.com. Published 10th February. 

When February 2010 rolls around, Ben Mates will be the first Australian male half-pipe snowboarder to have qualified for two Winter Olympic Games.  And this time round he did it on his own terms and with his own green. Put that in ya crack pipe and smoke it.  He has spent the past four years free of any restrictions, focusing on hunting down the Olympic standard 22ft pipes and elite-level competition that would provide him the means to qualify for Vancouver 2010.  In doing so the south coast local has succeeded whilst flipping the bird at the sports establishment that seemingly did not want anything to do with him. There is no doubt Mates is antiauthoritarian. A ‘fuck em if they can’t take a joke’ kind of guy.  It is a refreshing attitude.    Anarchist Athlete founder Jason Harding caught up with Ben via email just before he drops in and throws down at the 2010 O-Show.  Words Jason Harding.  Images Andrew Fawcett, Mike Weyerhaeuser, C laurila.  JH: So Ben, you just qualified for your second consecutive Winter Olympic Games. The first Australian male halfpipe rider to ever pull that off. How fucken cool is that. I hear you are at some private resort training at the moment. Sounds like a bit of a pamper package to me, complete with massages, manicures, the works. Where is your head at right now and how is your preparation heading into the 2010 Winter Olympics in Vancouver?  BM: Yeah I’m pretty stoked to have managed to qualify for my second Winter Olympics, It’s something I worked really hard for and I always knew I could do it. I am currently Training at Otsego Resort in Michigan USA, it is a private ski hill so the hill is fairly uncrowded which has made for some great training. The resort has provided everything we need with a 22 foot pipe, 22ft spine into a huge air bag to practice our tricks. They also have great food and have provided us with some fun activities to keep us occupied when we are off the hill like skeet shooting, ice fishing and plenty of rides on ski doo’s. It’s been great riding with the other Aussies Nate and Holly and the coach Andrew Burton has definitely helped my riding over the past week. I’m feeling pretty good heading into Vancouver.  Read Full Paper …

8.  Analysis of Half-Pipe Snowboarding Performance During Three Years Of The Burton Open Australian Half-Pipe Championships. 

Harding JW, James DA.  (2010)  Analysis of Half-Pipe Snowboarding Performance During Three Years Of The Burton Open Australian Half-Pipe Championships.  International Journal of Performance Analysis in Sport; 10 (1):  47-53.  

Half-pipe snowboarding performance is assessed by subjective measures.  Knowledge of the relative importance of objective performance indicators however can improve training and competition performance assessment.  We analysed previously developed key performance indicators at the Burton Open Australian Half-Pipe Championships over three years (2006, 2007, 2008). Linear regression showed the two individual key performance indicators most strongly correlated to competition success and multiple linear regression (enter method) showed the shared variance in scores explained by these objective variables.  The two objective performance variables most highly correlated with competition success were average air time (AAT) and average degree of rotation (ADR).  When combined (multiple linear regression), AAT and ADR objectively explain 71 – 94% of shared variance in subjective competition scores.  We compared magnitudes of differences in AAT and ADR between athletes achieving top three (podium) final rankings and those achieving final rankings outside the top three.  Magnitude of difference between athletic performances was established with a standardised (Cohen’s) effect size (ES) with 95% confidence limits.  Differences in AAT and ADR between athletes placing in top three and those finishing outside top three routinely showed moderate (ES = 0.6 – 1.2 95% CL) to very large (ES > 2.0 95% CL) effects.  Read Full Paper …

9.  Performance Assessment Innovations For Elite Snowboarding  

Harding JW, James DA. (2010) Performance Assessment Innovations For Elite Snowboarding. In: The Engineering of Sport 8, pp 2919 – 2924, Eds: Sabo A, Kafka P, Litzenberger S, Sabo C; Elsevier, Amsterdam.

This paper provides a review of objective performance assessment in elite half-pipe snowboarding.  Half-pipe snowboarding is currently coached and judged in competition using subjective measures.  Like other sports that rely on subjectivity however, the methodology underpinning how coaches assess athletic progression and judges score performance is open for debate. The current reliance on subjective performance assessment in half-pipe training and athlete preparation fails to utilize the benefits of objective information. In competition, the reliance on subjectivity is an open door for potential bias and judging corruption. For coaches, athletes and judges who are involved in elite snowboarding competition, objective performance assessment is something that is yet to be utilized to its full potential. This paper therefore focuses on technology assisted, objective performance assessment with the potential to improve athletic performance and judging reliability.  Key considerations are the specificity of the information, the accuracy and reliability of results, the processing time required and the current accessibility.  Read Full Paper … 

10.  Vibration of Snowboard Decks  

Fuss FK, Cazzolato B, Shepherd A, Harding JW. (2010) Vibration of Snowboard Decks.  In: The Engineering of Sport 8, pp 2863 – 2867, Eds: Sabo A, Kafka P, Litzenberger S, Sabo C; Elsevier, Amsterdam.

Vibrations of snowboards are closely related to their performance. The aim of this study was to investigate the frequencies of bending and torsional modes, the damping ratios and location of node lines in two boards with different torsional stiffness under free-free boundary conditions with a non-contact laser vibrometer. The frequencies of the first three bending modes were at 16, 37, and 65 Hz. The frequencies of the first three torsional modes were at 30, 54 and 86 Hz in one board, and 10% higher in the 2nd board. The damping ratios of the two boards investigated ranged between 0.3 and 0.6% for bending and between 0.6 and 1% for torsion. The location of the node lines was comparable to a free-free beam with constant cross-section. Vibration analysis should be a standard investigation for benchmarking of snowboards, in addition to mechanical and geometrical parameters.  Read Full Paper…

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