GPS analysis of a team competing at a national Under 18 field hockey tournament

The purpose of this study was to utilise global-positioning system (GPS) technology to quantify the running demands of national Under 18 field hockey players competing in a regional field hockey tournament. Ten male players (mean ± SD; age 17.2 ± 0.4 years; stature 178.1 ± 5.2 cm; body mass 78.8 ± 8.8 kg) wore GPS units while competing in six matches over seven days at the 2018 New Zealand national under 18 field hockey tournament. GPS enabled the measurement of total distance (TD), low-speed activity (LSA; 0 -14.9 km/hr), and high-speed running (HSR; ≥ 15 km/hr) distances. Differences in running demands (TD, LSA, HSR) between positions were assessed using effect size and percent difference ± 90% confidence intervals. Midfielders covered the most TD and LSA per game and strikers the most HSR during the 6 matches. There were “very large” differences between strikers and midfielders for TD and LSA, strikers and defenders for LSA and HSR, and defenders and midfielders for LSA. These results suggest that these playing positions are sufficiently different to warrant specialised position-specific conditioning training leading into a field hockey tournament

The effects of morning preconditioning protocols on testosterone, cortisol and afternoon sprint cycling performance [conference presentation]

Opportunities exist for athletes to undertake morning exercise protocols in an attempt to potentate afternoon performance. Four sub elite track sprint cyclists completed a morning cycling (Cyc) or weights-based protocol (WP) prior to an afternoon cycling time trial (500m) in a repeated measures, counterbalance crossover design. Measured variables included heart rate, blood lactate, cycling peak power, salivary testosterone (T) and cortisol levels along with time trial performance. Standardised differences in means via magnitude-based inferences were calculated using paired samples T-tests in SPSS version 24 with statistical significance set at p < 0.05. The WP produced significantly faster times in the final 250m in comparison to CycP. The anticipated circadian decline of T was observed after the CycP but was however mitigated following the WP. While slight decreases in 500m times were experienced during the WP, they were not significant and were considered within the normal variations experienced between performances by elite athletes. The effect of the WP on the circadian rhythm of T could be linked to a greater recruitment of muscle fibres. Results suggest a morning resistance protocol can positively affect testosterone levels for afternoon performance. Possible gender and individual responses from conducting a W over Cyc protocol were observed and require further investigation

Hydration and Fluid Needs during Physical Activity

Hydration during physical activity is a key component of both performance and safety. Several factors impact hydration, including, but not limited to: environmental conditions, such as heat and humidity; clothing and cooling strategies; individual fluid losses measured by sweat rate, sweat composition, dietary composition, and nutrition behaviors; and individual attitudes and perceptions of thirst. This Special Issue, “Hydration and Fluid Needs During Physical Activity”, discusses current knowledge and recommendations for assessing, monitoring, and maintaining sufficient hydration during exercise and sport for a diverse range of populations, sports, and conditions. It consists of eleven peer-reviewed papers that cover several aspects relevant to hydration and physical activity

Eye quietness and quiet eye in expert and novice golf performance: an electrooculographic analysis

Quiet eye (QE) is the final ocular fixation on the target of an action (e.g., the ball in golf putting). Camerabased eye-tracking studies have consistently found longer QE durations in experts than novices; however, mechanisms underlying QE are not known. To offer a new perspective we examined the feasibility of measuring the QE using electrooculography (EOG) and developed an index to assess ocular activity across time: eye quietness (EQ). Ten expert and ten novice golfers putted 60 balls to a 2.4 m distant hole. Horizontal EOG (2ms resolution) was recorded from two electrodes placed on the outer sides of the eyes. QE duration was measured using a EOG voltage threshold and comprised the sum of the pre-movement and post-movement initiation components. EQ was computed as the standard deviation of the EOG in 0.5 s bins from –4 to +2 s, relative to backswing initiation: lower values indicate less movement of the eyes, hence greater quietness. Finally, we measured club-ball address and swing durations. T-tests showed that total QE did not differ between groups (p = .31); however, experts had marginally shorter pre-movement QE (p = .08) and longer post-movement QE (p < .001) than novices. A group × time ANOVA revealed that experts had less EQ before backswing initiation and greater EQ after backswing initiation (p = .002). QE durations were inversely correlated with EQ from –1.5 to 1 s (rs = –.48 - –.90, ps = .03 - .001). Experts had longer swing durations than novices (p = .01) and, importantly, swing durations correlated positively with post-movement QE (r = .52, p = .02) and negatively with EQ from 0.5 to 1s (r = –.63, p = .003). This study demonstrates the feasibility of measuring ocular activity using EOG and validates EQ as an index of ocular activity. Its findings challenge the dominant perspective on QE and provide new evidence that expert-novice differences in ocular activity may reflect differences in the kinematics of how experts and novices execute skills

Spartan Daily, April 16, 1985

Volume 84, Issue 49https://scholarworks.sjsu.edu/spartandaily/7302/thumbnail.jp

Spartan Daily, August 30, 2002

Volume 119, Issue 3https://scholarworks.sjsu.edu/spartandaily/10647/thumbnail.jp

Effects of Expected Service Life Exposures on the Functional Properties and Impact Performance of an American Football Helmet Outer Shell Material

The purpose of this dissertation is to gain a greater scientific understanding of the changes in functional material properties and impact performance of an American football helmet outer shell material under expected service life exposures. The research goals are to (i) quantify chemical, physical, thermal, and mechanical degradation of an American football outer shell material under expected environmental conditions and (ii) develop a linear drop test impact protocol to employ expected on-field impact conditions to American football helmet components and a plaque-foam (i.e., shell-liner) surrogate. Overall, a step-wise progression of analysis was demonstrated to concurrently quantify and understand changes in material properties at the molecular, microscopic, and macroscopic levels. Changes across chemical, physical, thermal, and mechanical properties were evaluated following laboratory exposures to 480 hours of accelerated weathering, increasing intensities of n-Butyl acetate solvent, and 12 repetitive linear plaque-foam impacts. In Chapter II, an instrumented drop test setup was substantiated to investigate linear impact attenuation performance. In Chapter III, laboratory exposure to UV light, oxygen, moisture, and elevated temperatures induced molecular degradative bi-products and physical aging up to ~1% into the plaque thickness which led to altered aesthetic properties, chemi-crystallization, and an increased resistance to surface indentation and tensile deformation. In Chapter IV, solvent-induced plasticization, crystallization, and stress-cracking of up to ~3% into the plaque thickness led to an increase in surface porosity which scattered light and decreased tensile properties. In Chapter V, impact exposure induced rubber-toughener (RT) cavitation that generated voids via delamination at the RT-matrix interface at which led to rings of stress-whitening, strain-induced crystallization, increased butadiene RT density, and shifts surface modulus and tensile properties. This dissertation preliminarily substantiated (i) a drop test setup attempting to accurately replicate on-field impact conditions to investigate linear impact attenuation performance, and (ii) polymer techniques and protocols that could elucidate the rates and degrees of material degradation

An investigation of heat stress epidemiology, prevention guidelines, and sporting environment

As temperatures rise, the frequency of heatwaves, extreme summer heat and less night-time cooling increases. An uncontrolled increase in heat production affects performance and subsequently affects the health of the athlete resulting in exertional heat illness (EHI). EHI is a result of an uncontrollable rise in core body temperature arising from a thermoregulatory response. With rising temperatures, the risk of EHI when exercising or participating in sport increases. However, assessing the risk of EHI is contingent on accurate epidemiological data and addressing the risk of EHI is reliant on effective evidence-based interventions. This thesis assessed the risk of EHI through four interlinked studies: (ⅰ) an analysis of heat-related sports and leisure hospitalisations and emergency department presentations to determine trends in incidence rates and compare them with meteorological trends; (ⅱ) a document analysis of all sports and leisure activity heat-related injury prevention resources in Australia to develop an understanding of the content within those resources; (ⅲ) an investigation of surface temperatures of commonly used artificial sports surfaces to assess the risk posed by such surfaces and measure the differences in microclimates; and, (ⅳ) an assessment of the concordance of meteorological data of multiple artificial sports surfaces with meteorological data from the nearest Bureau of Meteorology (BOM) weather station and a local City of Ballarat (COB) environmental monitoring system (EMS). A total of 1055 heat injury hospitalisations and emergency department (ED) presentations were recorded between July 2008 and June 2018, which included 171 sport-related hospitalisations,139 ED presentations, 83 leisure-related hospitalisations and 662 ED presentations. There were significant correlations between ED presentations for heat-related sports injuries and mean, minimum and maximum temperature, mean and maximum temperature anomaly, summer maximum temperature, and summer maximum temperature anomaly. Three overarching categories emerged through the document analysis process: preventive strategies (n=299, 63.9%), risk factors (n=94, 20.1%), and treatment (n=75, 16.0%). Activity modification, which included information on rescheduling games and extra breaks, was the most common intervention. Cricket, soccer, swimming, and triathlon had the most complete set of heat resources. During the 2020–2021 summer period a total of 1245 measurements were recorded across five artificial sports surfaces: athletics, hockey, lawn bowls, soccer, tennis. The lawn bowls turf was the hottest surface with a mean surface temperature of 54.43 (± 13.46) °C. An increase in surface temperature corresponded to an increase in air temperature, wet bulb temperature and a decrease in relative humidity but the effect varied across the five surfaces. An increase in solar radiation and air temperature also corresponded to an increase in surface temperature. On all five surfaces measured, the BOM air temperatures were the lowest, followed by the on-site air temperatures and then the COB air temperatures on all surfaces. The highest Wet Bulb Globe Temperature (WBGT) measurements of 24.38 (± 2.39) °C were recorded by the COB sensor, while the lowest WBGT measurements 20.76 (± 1.99) °C were recorded by the BOM. There was a statistically significant difference in the WBGT categorisation between on-site estimate measurements and BOM measurements, p <0.001. The incidence of heat-related hospitalisations and ED presentations provides a baseline from which heat-related guidelines and interventions can be developed, evaluated, and modified. Heat resources considered in the document analysis suggest EHI is preventable if appropriate precautions are implemented. With a focus on preventing EHI, heat resources mainly provided recommendations on modifying activities and reducing exposure to extreme conditions. These results imply the EHI risk posed by artificial sport surfaces are not uniform and safety polices should be updated to reflect the link between air temperature and surface temperature. Understanding how surface temperature is influenced by air temperature, solar radiation and cloud cover allows for more accurate predictions of playing conditions on these artificial sport surfaces. Differences were observed between the individual meteorological measurements, the WBGT measurements and the heat stress categorisation. Overall, a significant discord existed for both individual meteorological variables and WBGT modelled from multiple sources of available data. The findings from this thesis have implications for athlete welfare and strengthening future interventions. Overall, this doctoral research project quantifies the scale of heat-related injuries, reviews the policies to address these heat-related injuries and provides new knowledge on the risk posed by artificial sports surfaces.Doctor of Philosoph

Pain perception in contact sports

La douleur est une sensation universelle pour qui les termes descriptifs élicitent une reconnaissance immédiate. Les sensations de brûlure, de démangeaisons ou de tranchements aigus servent de signal d’alarme ayant pour but d’éviter des dommages corporels. Chez les athlètes, cette alerte est souvent ignorée afin d’atteindre l’excellence en performance. Dépendant du sport, le type de douleur ressenti peut varier. Dans le cas des athlètes d’endurance, la douleur survient naturellement dans le muscle due aux contractions répétées sur une longue période. Alternativement, les athlètes pratiquant un sport de contact doivent aussi anticiper de la douleur « mécanique » produite par des coups infligés par les adversaires. La différence dans la demande et la spécificité de chaque sport sont cependant rarement prises en considération dans les études sur la douleur chez les athlètes. Dans le cadre de ce mémoire de maitrise, une revue de portée a été réalisée pour mieux comprendre comment la perception de la douleur chez les athlètes de sports de contact est étudiée. Trois composantes ont été analysées : Les types de sports de contacts étudiés, les groupes auxquels ils sont comparés, et les méthodes utilisées pour induire expérimentalement la douleur. Onze études ont été retenues. Deux sous-catégories de sports de contact ont été identifiées. Les sports de combat ont plus souvent été inclus dans ces études que les sports d’équipe. Ces athlètes étaient comparés à des groupes composés de non-athlètes et d’athlètes de sports « non-contact ». Quatre méthodes d’induction expérimentale de la douleur ont été utilisés, soit, la pression mécanique, le froid, la chaleur et l’ischémie musculaire. Une justification des choix de méthode d’induction de la douleur ou types d’athlètes inclus dans le cas d’un groupe contrôle de sport non-contact est rarement fourni. Un vide existe dans la littérature quant à la comparaison de la perception de la douleur d’athlètes de sport de contact avec un groupe d’athlètes non-contact et une méthode d’induction expérimentale de la douleur choisi délibérément pour mieux refléter la réalité de la pratique sportive. Un protocole expérimental est proposé pour combler ce besoin.Pain is a universal sensation whose descriptive terms elicit immediate recognition. The burning, itching, or sharp feelings serve as an alarm system meant to avoid bodily harm. In athletes, this warning is often ignored in the pursuit of performance. Depending on the sport, the type of pain encountered can vary. In the case of endurance athletes, pain occurs naturally within the muscle due to repeated contraction over a long period. Alternatively, athletes in contact sports must also anticipate mechanical pain caused by opponents. The difference in demand and the specificity of each sport are however very rarely taken into consideration when studying pain in athletes. A scoping review was used to better understand how pain perception in contact sport athletes is being studied. Three components were analysed: the types of contact sports being studied, the groups they are being compared to, and the methods used to experimentally induce and study pain. A total of 11 articles were included. Two subcategories of contact sport were identified. Combat sports were more often included in studies than team contact sport. These athletes were compared to both non-athletes and non-contact athletes. Four methods of experimental pain induction were used, namely, the pain pressure test, the cold pressor test, an ischemic pain protocol, and heat pain protocol. Justification was not always provided for either pain protocol selection or non-contact athletes selected as control group. A gap exists in the literature in comparing contact sport athletes’ pain perception with a deliberately chosen athlete control group using a pain induction protocol meant to emulate a facet of pain experienced during exercise. A protocol proposal is included in the discussion to meet this demand