The science and art of testing in ice hockey: a systematic review of twenty years of research

IntroductionIce hockey is a complex sport requiring multiple athletic and technical attributes. Considering the variety of tests developed, on-ice testing protocols have been created to measure the physiological and mechanical attributes associated with performance. To our knowledge, a lack of technical resources exists to help stakeholders opt for on-ice protocols from among those developed. It becomes crucial for researchers and practitioners to select relevant and context-specific procedures. This systematic review of the literature outlines an inventory of the on-ice tests that have been used in the domain of ice hockey research over the last twenty years, and summarize protocols mostly used in major athletic components.MethodsA search was performed on three databases (PubMed, SPORTDiscus and Scopus) by following the PRISMA guidelines. Specific keywords were selected to find publications using on-ice testing protocols in the methodology. Four aspects of athletic attributes were used to categorize the protocols: aerobic capacity, acceleration-speed, agility-change of direction and ability to repeat skating sprints. Analyses were conducted regarding four categories of observations: population under study, on-ice reported test(s), outcomes measures and main findings.ResultsA total of 107 articles were included, resulting in 55 on-ice tests related to the on-ice assessments of four major athletic components: aerobic capacity (n = 7), acceleration-speed (n = 6), agility and change of direction (n = 23) and repeated skating sprint ability (n = 19). Testing in male and older cohorts (≥16 years old) predominates, with a primary focus on the competitive amateur level. The selected tests were mainly designed for assessing on-ice physiological responses and fitness (n = 38), talent identification-team selection (n = 19), efficiency of interventions (n = 17) and validation purposes (n = 16).ConclusionA prevalence of on-ice skating tests to assess the ability to repeat intense efforts, agility, acceleration and speed components exists, which are relevant and linked to match requirement. The wealth of on-ice tests used in the literature reflects the need to adapt the on-ice evaluation process to the population, constraints, and goals. This review is a valid toolbox and can benefit for researchers and practitioners interested in testing hockey players from different levels, with a variety of aims and needs, by helping them to select the relevant procedures to their environment and practice context

Measuring relay exchange kinematics in short-track speed skating using a multi-camera network

To support their targeted improvement of the relay exchange, Great Britain Speed Skating required a tool that could be used to advance knowledge on ‘how to execute the relay exchange effectively’. A tool that measures relay exchange kinematics in representative race scenarios, over its entirety, and with an acceptable level of measurement error (± 0.19 m·s-1). A review of existing measurement solutions found that the Olympic Oval (CAN) multi-camera network was the only tool that came close to meeting this criterion. However, while this multi-camera network satisfied the metrics, scenarios, and scope of relay exchange measurement, its ± 1.53 m·s-1 error exceeded the target measurement error. For these reasons, this thesis developed a multicamera network to measure accurate, two-dimensional, relay exchange kinematics. The literature review identified that the accuracy of the National Ice Centre (GBR) multi-camera network was dependent on five sources of measurement error. Accordingly, a series of investigations quantified how these errors propagated, independently, to errors in relay exchange kinematics. In the case where these errors exceeded the target measurement error, additional studies investigated minimising each error. Using this empirically informed measurement workflow, Monte Carlo simulations showed that the multi-camera network’s total error was ± 0.17 m·s-1. This error was within the target measurement error and significantly less than the benchmark Olympic Oval (CAN) multi-camera network. Investigations into the execution of the relay exchange demonstrated how this reduction in error allowed Great Britain Short-Track Speed Skating to advance knowledge on ‘how to execute the relay exchange effectively’. In turn, supporting the team’s targeted improvement of the relay exchange, and ultimately, their aim of delivering medal-winning performances at the Winter Olympic Games

Développement d’outils d’évaluations de la performance physiologique et technique sur glace du joueur de hockey élite de moins de 18 ans

L'objectif général de cette thèse de doctorat était de développer des outils afin d’améliorer l'évaluation sur glace de jeunes joueurs de hockey sur glace d'élite. Pour ce faire, 4 projets de recherche ont été menés. Le premier projet consistait, par un suivi longitudinal, à suivre l’évolution du profil morphologique, physiologique et des habiletés patinage qui caractérise les joueurs de hockey sur glace d’élite impliqués dans les ligues de développement. Au total, 18 joueurs ont été mesurés lors de séances d’évaluation hors glace et sur glace au début, à la fin de la saison et au début de la saison suivante. On a constaté que la puissance aérobie maximale s’est maintenue durant la saison de hockey malgré le peu de temps investi afin de maintenir cette qualité physique. Ce phénomène s’explique par le fait que la nature du jeu ainsi que l’intensité des entraînements sur glace étaient suffisantes pour conserver une valeur de V̇O2max respectable durant toute la saison. Toutes les habiletés de patinage se sont améliorées pendant la saison de hockey, mais pas pendant la saison morte où une certaine dégradation a été observée. Plus particulièrement, on a observé que le faible pourcentage des variances communes expliquées (<20%) entre les variables physiologiques mesurées hors glace et les tests de performance sur glace indiquaient des lacunes importantes, tant dans le choix des outils d’évaluation hors glace que dans les méthodes d’entraînement conventionnellement utilisées. Pour ces différentes raisons, l’objectif du second projet a été de mettre à jour, les valeurs de V̇O2 obtenues au cours du Skating Maximal Aerobic Test (SMAT) et de proposer un indice d’efficacité de patinage (Skating Stride Index; SSI) permettant d’améliorer la prédiction du coût en oxygène. En effet, le SMAT, comme la plupart des tests de terrain, suppose que les participants qui atteignent un palier donné obtiennent la même valeur de consommation d’oxygène, ce qui n’est généralement pas le cas. Ainsi, 26 joueurs de hockey élites ont été évalués au cours du SMAT et leurs résultats ont été analysés afin de déterminer la contribution d’un nouvel indice d’évaluation de l’économie de patinage sur la performance sur glace. Un SSI, associé à la vitesse maximale de l’épreuve a ainsi été développé et a permis d’améliorer la précision des valeurs de V̇O2 prédites (r=0,95, SEE=1,92). En comparant le SSI des joueurs, on a noté que les valeurs de V̇O2 pouvaient varier de plus de 5ml∙kg-1∙min-1 à l’intérieur d’un même palier, suggérant l’importance d’inclure le SSI dans la prédiction du V̇O2max. Par la suite, dans un troisième projet, nous avons évalué la robustesse des équations de prédiction du coût en O2 dans quatre différentes situations de patinage anaérobie. À ce titre, 24 joueurs élites pour lesquels le temps d'exécution, la fréquence cardiaque, le V̇O2, les foulées et le SSI ont été mesurés pour chaque test. Les quatre équations de régression ont affiché des coefficients de corrélation variant de 0,91 à 0,93 et une SEE se situant entre 4,5 et 8,4%, suggérant à nouveau que le temps d'exécution à lui seul, est un mauvais prédicteur de la consommation d’O2 requise pour ce type d'effort. L’introduction d’un SSI permettra ainsi aux entraîneurs d’obtenir des informations plus précises concernant le développement des habiletés de patinage puisqu’on a notamment constaté que les jeunes joueurs ont généralement une efficacité de patinage inférieure à celle des joueurs plus âgés. Finalement, le but de notre dernier projet a été d’examiner la capacité prédictive de nos algorithmes permettant d’estimer le coût en oxygène et le taux de lactate à l’aide d’une épreuve mesurant la capacité anaérobie lactique sur glace (12x18m). Pour ce faire, 20 joueurs élites ont subi le test au terme duquel l’accumulation du lactate post-effort a été mesurée. L’inclusion du SSI dans l’équation de prédiction afin de prédire le taux de lactate a eu un impact majeur en faisant passer la corrélation du modèle de régression multiple de 0,54 à 0,87 tout en réduisant l’erreur-type de l’estimé de 10,4% à 6,5%. Ce constat rejoint celui émis par Saltin et al. (1972) qui rapportaient l’importance de considérer un indice de rendement mécanique dans ce type d’épreuve. Nos résultats ont ainsi permis de développer des outils de prédiction précis afin d’estimer les valeurs de V̇O2 absolues (r=0,87 ; SEE=0,19) et de lactate (r=0,87 ; SEE=0,94). D’un point de vue pratique, les nouveaux algorithmes développés donneront l’opportunité aux entraîneurs de ne pas avoir recours à la collecte de prélèvements sanguins afin de déterminer la concentration maximale de lactate accumulée. Ainsi, nos travaux auront permis de développer des outils d’évaluation sur glace accessibles tant aux scientifiques qu’aux entraîneurs. The general objective of this doctoral thesis was to develop tools to improve the on-ice assessment of young elite ice hockey players. The first part was, through a longitudinal follow-up, to monitor the evolution of the morphological, physiological and skating skills profile that characterize youth players involved in elite ice hockey development leagues. Eighteen (18) players were evaluated off-ice and on-ice at the beginning, end, and at the beginning of the following season. We noticed that the maximal aerobic power was maintained during the hockey season despite little time invested to develop this physical quality. This phenomenon is explained by the fact that the nature of the game as well as the intensity of the on-ice training sessions were enough to maintain a respectable V̇O2max value throughout the season. All skating skills improved during the hockey season, but not during the off-season when some degradation was observed. Specifically, it was observed that the low percentage of common variance (<20%) between physiological variables measured off-ice and skating performance tests assessed on-ice, indicated significant shortcomings in both the choice of conventionally off-ice training methods as well as off-ice assessment tools. For these different reasons, the objective of the second project was to update the V̇O2 values obtained during the Skating Maximal Aerobic Test (SMAT) and to propose a Skating Stride Index (SSI) in order to improve the prediction of oxygen uptake. Indeed, the SMAT, like most field tests, assumes that participants who reach a given level have the same oxygen consumption, which is not usually the case. An SSI was developed, and when associated with the maximum speed achieved during the test, the accuracy of the predicted V̇O2 values was improved (r=0.95, SEE=1.92). When comparing players' SSI, it was noted that the V̇O2 values could vary by more than 5ml∙kg-1∙min-1 within the same stage, suggesting the importance of including the SSI in the prediction of V̇O2max. Subsequently, in a third project, we evaluated the robustness of the O2 cost prediction equations in four different anaerobic skating situations. As such, 24 elite players participated in this study for whom the execution time, heart rate, V̇O2, skating strides and SSI were measured for each test. The four regression equations displayed correlation coefficients ranging from 0.91 to 0.93 and a SEE between 4.5 to 8.4%, suggesting that the execution time alone is a poor predictor of O2 uptake required for this type of effort. The introduction of the SSI will allow coaches to obtain more precise information concerning the development of skating skills of their players, since it has notably been observed that young players generally have a lower skating efficiency than older players do. Finally, the goal of our last project was to examine the predictive value of our algorithms to estimate oxygen cost and lactate level using an on-ice anaerobic lactic capacity test. Thus, 20 elite players were tested, and post-exercise lactate accumulation was measured. The inclusion of the SSI had a major impact in the lactate level prediction by improving the correlation of the multiple regression model from 0.54 to 0.87, while reducing the standard error of the estimate from 10.4% to 6.5%. This finding is consistent with the results presented by Saltin et al. (1972) who reported the importance of considering an index of mechanical efficiency in this type of test. Our results have led to the development of accurate prediction tools to estimate absolute V̇O2 (r=0.87, SEE=0.19) and lactate level values (r=0.87, SEE=0.94). From a practical point of view, the new algorithms developed will help coaches to determine the maximum lactate concentration without requiring the use of blood samples. Thus, our work will have enabled the development of on-ice assessment tools available to both scientists and coaches

Physiological contributions to successful downhill mountain bike performance

Purpose: To, one, investigate the anatomical and physiological attributes of Downhill mountain bike athletes and, two, to determine the influence of these inherent physiological attributes on Downhill race performance. Methods: The study consisted of two testing components; laboratory- and field-based testing. Laboratory study: An anthropometric profile was determined from seven trained and competitive DH athletes (age 21 ± 5 years). Peak power output and time to peak power were determined by six, 6-second maximal sprints, performed on an SRM stationary ergometer. Cadence was restricted during five sprints (60, 80, 100, 120 and 140 rpm) to determine optimal cadence for achieving peak power. Field study: Twelve trained and competitive DH athletes (age 20 ± 5 years) performed two timed runs of a National Championship DH course. Heart rate was recorded and two GPS units (attached to the bicycle and helmet) recorded speed (kmhr¬¬-1), distance (m), time (seconds) and impacts (g). Results: Laboratory study: DH cyclists have predominantly mesomorphic somatotypes (mean somatotype values, 2.1,4.7,3.0) with a mean sum of 8 skinfolds, 68.7 ± 19.8 mm. Sprint testing revealed peak power output (23.36 ± 2.12 Wkg-1) was achieved at restricted cadence of 110 rpm and time to peak power output was 1.5 ± 0.9 seconds. Field study: DH race run time was 178.57 ± 12.10 seconds. Analysis showed two areas of the DH course to affect overall performance; start of the race and the technical section (r = 0.76 and r = 0.94, respectively). Correlation equations identified mean distance travelled in the first 5, 6 and 10 seconds of the race (22.0 ± 2.8 m, 30.5 ± 3.1 m and 70.4 ± 6.2 m, respectively) had a positive influence (p < 0.05) on overall run time. Peak (28.5 ± 3.4 kmhr¬¬-1) and mean (16.8 ± 1.9 kmhr¬¬-1) speed during the technical section (course Section 4) had a positive effect on performance time (p < 0.05) Correlation equations between laboratory and field-testing identified peak power output and time to peak power had a positive influence (p < 0.05) on the start of the race (first 15 seconds) and thus, overall performance. Conclusions: DH is a dynamic, high intensity cycling discipline with many factors influencing performance. Whilst technical skills are essential, results identified that physiological parameters (peak power output and time to peak) can positively affect the start section of a run (p = 0.049 and p = 0.032), and in turn, overall race time. Therefore, training to improve these measures would be appropriate for DH athletes

Aerodynamics of Track Cycling

The aim of this thesis was to identify ways in which the velocity of a track cyclist could be increased, primarily through the reduction of aerodynamic drag, and to determine which factors had the most significant impact on athlete performance. An appropriate test method was set up in the wind tunnel at the University of Canterbury to measure the aerodynamic drag of different cycling positions and equipment, including helmets, skinsuits, frames and wheels, in order to measure the impact of specific changes on athlete performance. A mathematical model of the Individual Pursuit (IP) event was also created to calculate the velocity profile and finishing time for athletes competing under different race conditions. The model was created in Microsoft Excel and used first principles to analyse the forces acting on a cyclist, which lead to the development of equations for power supply and demand. The mathematical model was validated using SRM data for eleven, elite track cyclists, and was found to be accurate to 0.31s (0.16%). An analysis of changes made to the bike, athlete, and environmental conditions using the mathematical model showed that the drag area and air density had the greatest impact on the finishing time. The model was then used to predict the finishing times for different pacing strategies by generating different power profiles for a given athlete with a fixed stock of energy (the work done remained the same for all generated power profiles) in order to identify the optimal pacing strategy for the IP. The length of time spent in the initial acceleration phase was found to have a significant impact on the results, although all strategies simulated with an initial acceleration phase resulted in a faster finishing time than all other strategies simulated. Results from the wind tunnel tests showed that, in general, changes made to the position of the cyclist had the greatest impact on the aerodynamic drag compared to changes made to the equipment. Multiple changes in position had a greater impact on drag than individual changes in position, but the changes were not additive; the total gain or loss in drag for multiple changes in position was not the sum of individual gains or losses in drag. Actual gains and losses also varied significantly between athletes, primarily due to differences in body size and shape, riding experience, and reference position from which changes were made from. Changes in position that resulted in a reduction of the frontal area, such as lowering the handlebars and head, were the most successful at reducing the aerodynamic drag, and a change in skinsuit was found to have the greatest impact on drag out of all equipment changes, primarily due to the choice of material and seam placement. The mathematical model was used to quantify the impact of changes in position and equipment made in the wind tunnel on the overall finishing time for a given athlete competing in an IP event. Time savings of up to 8 seconds were seen for multiple changes in position, and up to 5 seconds for changes to the equipment. Overall this thesis highlights the significance of aerodynamics on athlete performance in track cycling, suggesting that it is worthwhile spending time and money on research and technology to find new ways to reduce the aerodynamic drag and maximise the speed of cyclists. Although this thesis primarily concentrates on the Individual Pursuit event in track cycling, the same principles can be applied to other cycling disciplines, as well as to other sports

Friction Force Microscopy of Deep Drawing Made Surfaces

Aim of this paper is to contribute to micro-tribology understanding and friction in micro-scale interpretation in case of metal beverage production, particularly the deep drawing process of cans. In order to bridging the gap between engineering and trial-and-error principles, an experimental AFM-based micro-tribological approach is adopted. For that purpose, the can’s surfaces are imaged with atomic force microscopy (AFM) and the frictional force signal is measured with frictional force microscopy (FFM). In both techniques, the sample surface is scanned with a stylus attached to a cantilever. Vertical motion of the cantilever is recorded in AFM and horizontal motion is recorded in FFM. The presented work evaluates friction over a micro-scale on various samples gathered from cylindrical, bottom and round parts of cans, made of same the material but with different deep drawing process parameters. The main idea is to link the experimental observation with the manufacturing process. Results presented here can advance the knowledge in order to comprehend the tribological phenomena at the contact scales, too small for conventional tribology

Towards a Conceptual Design of an Intelligent Material Transport Based on Machine Learning and Axiomatic Design Theory

Reliable and efficient material transport is one of the basic requirements that affect productivity in sheet metal industry. This paper presents a methodology for conceptual design of intelligent material transport using mobile robot, based on axiomatic design theory, graph theory and artificial intelligence. Developed control algorithm was implemented and tested on the mobile robot system Khepera II within the laboratory model of manufacturing environment. Matlab© software package was used for manufacturing process simulation, implementation of search algorithms and neural network training. Experimental results clearly show that intelligent mobile robot can learn and predict optimal material transport flows thanks to the use of artificial neural networks. Achieved positioning error of mobile robot indicates that conceptual design approach can be used for material transport and handling tasks in intelligent manufacturing systems

Towards a Conceptual Design of an Intelligent Material Transport Based on Machine Learning and Axiomatic Design Theory

Reliable and efficient material transport is one of the basic requirements that affect productivity in sheet metal industry. This paper presents a methodology for conceptual design of intelligent material transport using mobile robot, based on axiomatic design theory, graph theory and artificial intelligence. Developed control algorithm was implemented and tested on the mobile robot system Khepera II within the laboratory model of manufacturing environment. Matlab© software package was used for manufacturing process simulation, implementation of search algorithms and neural network training. Experimental results clearly show that intelligent mobile robot can learn and predict optimal material transport flows thanks to the use of artificial neural networks. Achieved positioning error of mobile robot indicates that conceptual design approach can be used for material transport and handling tasks in intelligent manufacturing systems