The effect of training mode on the validity of training load measures for quantifying the training dose in professional rugby league

Establishing the accurate quantification of the training load is a key focus for researchers and sport scientists to maximise the likelihood of appropriate training prescription. In the field, there are numerous methods adopted to quantify the physiological, physical, mechanical, and other loads placed on team sports athletes, including global positioning systems, accelerometry, heart rate and session rating of perceived exertion. Each method can be classified within one of two theoretical constructs: the external or internal training load. Due to the lack of a gold standard criterion, previous research has investigated validity through relationships with criterion measures of load or dose-response associations with chronic changes in physical fitness. The current research designs within investigations into the validity of those methods have failed to consider the influence of the mode of training on the validity of the measures. As strength and conditioning coaches utilise a variety of training modes to stress the various physiological systems to promote the adaptations required to succeed in competition, investigating the influence of training type on training load validity is warranted.To achieve this, the research (Chapters 3-6) was conducted within two professional rugby league clubs, where training load data (global positioning system, accelerometry, heart rate, session rating of perceived exertion) were collected across three twelve week pre-season preparatory periods. Training sessions were demarcated by training mode. The results of the first study showed that meaningful differences in the distances covered within arbitrary speed-and metabolic power-derived-thresholds exist between field-based training modes (small-sided games, conditioning, skills, speed). These differences in external load also led to differences in the perceptual- and heart-rate-derived internal load response. Establishing how those differences in demands influence the relationships between multiple external and internal training load methods is important to establish the validity of individual methods across different modes of training. In our case study approach in study two, the main finding was that when session rating of perceived exertion (sRPE) demonstrated trivial differences across multiple skills training sessions, large variation was present (coefficient of variation range 31-93%) in other training load methods (individualised training impulse [iTRIMP], Body Load™, Total Number of Impacts, high-speed distance) which reduced (coefficient of variation range 3-78%) when sRPE demonstrated trivial differences during small-sided games. This provided initial evidence that training load measures provide different information which might be influenced by the training mode. However, a more comprehensive investigation was needed. In the third study we aimed to examine the influence of training mode on the variance explained between measures of external (arbitrary high-speed distance, Body Load™, total-impacts) and internal (iTRIMP, sRPE) training load over two twelve week pre-season preparatory periods. This was replicated in our fourth study, across a shorter period of training from a different team utilising different methods in which to represent the external (individualised high-speed distance, PlayerLoad™) and internal (heart rate exertion index [HREI], sRPE) training load. During both investigations, we determined the structure of the interrelationships of multiple internal and external load methods via a principal-component analysis (PCA). Within the findings of both investigations, the extraction of multiple dimensions (two principal components) in certain modes of training suggests a single training load measure cannot explain all the information provided by multiple measures used to represent the training load in professional rugby league players. Therefore, if a single measure is used this could underrepresent the actual load imposed onto players. However, establishing the ‘dose-response’ associations between training load and the changes in training outcomes, such as physical fitness is also needed to establish validity. As a result, during study five, we aimed to determine the influence of training mode on the ‘dose-response’ relationship between measures of external (PlayerLoad™ ) and internal (sRPE, HREI) training load and acute changes in physical performance (countermovement jump, 10- and 20-m sprint, Yo-Yo intermittent recovery test level 1) following conditioning and speed training. sRPE was the only training load measure to provide meaningful relationships with changes in Yo-Yo intermittent recovery test level 1 performance. This provides the first evidence of the acute dose-response validity of the sRPE method. No measure provided meaningful relationships with all changes in performance. Therefore, further investigation is warranted to establish whether a combination of measures reflect better those changes than individual measures. The findings of the thesis suggests that practitioner should consider the implementation of both external and internal training load methods within their monitoring practices and researchers should establish multivariate and mode-specific relationships between training load methods to elucidate appropriate evidence of validity

#USportsSoMale: Gender (In)equity in Canadian Interuniversity Varsity Sport

Herein we examine the current state of gender (in)equity within Canadian interuniversity varsity sport (U SPORTS). In so doing, we build upon the previous work of Canada’s Centre for Sport Policy Studies at University of Toronto (see Norman et al., 2021). In our examination, we accessed all 56 U SPORTS universities’ Department of Athletics official webpages. We investigated the opportunities for women to participate as student-athletes on U SPORTS interuniversity varsity sport teams as well as opportunities for women to serve as sport leaders as their universities’ Directors of Athletics (DAs) and head coaches. Our findings suggest the current situation in Canadian universities remains bleak. We also argue that immediate attention and action is needed—by multiple potential stakeholders—for meaningful change to occur. Finally, considering these findings, we offer suggestions for moving forward and creating change

Collision activity during training increases total energy expenditure measured via doubly labelled water

Purpose: Collision sports are characterised by frequent high intensity collisions that induce substantial muscle damage, potentially increasing the energetic cost of recovery. Therefore, this study investigated the energetic cost of collision-based activity for the first time across any sport. Methods: Using a randomised crossover design, six professional young male rugby league players completed two different five-day pre-season training microcycles. Players completed either a collision (COLL; 20 competitive one-on-one collisions) or non-collision (nCOLL; matched for kinematic demands, excluding collisions) training session on the first day of each microcycle, exactly seven days apart. All remaining training sessions were matched and did not involve any collision-based activity. Total energy expenditure was measured using doubly labelled water, the literature gold standard. Results: Collisions resulted in a very likely higher (4.96 ± 0.97 MJ; ES = 0.30 ±0.07; p=0.0021) total energy expenditure across the five-day COLL training microcycle (95.07 ± 16.66 MJ) compared with the nCOLL training microcycle (90.34 ± 16.97 MJ). The COLL training session also resulted in a very likely higher (200 ± 102 AU; ES = 1.43 ±0.74; p=0.007) session rating of perceived exertion and a very likely greater (-14.6 ± 3.3%; ES = -1.60 ±0.51; p=0.002) decrease in wellbeing 24h later. Conclusions: A single collision training session considerably increased total energy expenditure. This may explain the large energy expenditures of collision sport athletes, which appear to exceed kinematic training and match demands. These findings suggest fuelling professional collision-sport athletes appropriately for the "muscle damage caused” alongside the kinematic “work required”. Key words: Nutrition, Recovery, Contact, Rugb

A systematic map of studies testing the relationship between temperature and animal reproduction

Funding: This work was funded by the European Society for Evolution (which funds a Special Topic Network on Evolutionary Ecology of Thermal Fertility Limits to CF, AB, RRS and TARP), the Natural Environment Research Council (NE/P002692/1 to TARP, AB and RRS, NE/X011550/1 to LRD and TARP), the Biotechnology and \Biological Sciences Research Council (BB/W016753/1 to AB, TARP and RRS) and a Heisenberg fellowship from the German Research Foundation (FR 2973/11-1 to CF).1. Exposure to extreme temperatures can negatively affect animal reproduction, by disrupting the ability of individuals to produce any offspring (fertility), or the number of offspring produced by fertile individuals (fecundity). This has important ecological consequences, because reproduction is the ultimate measure of population fitness: a reduction in reproductive output lowers the population growth rate and increases the extinction risk. Despite this importance, there have been no large‐scale summaries of the evidence for effect of temperature on reproduction. 2. We provide a systematic map of studies testing the relationship between temperature and animal reproduction. We systematically searched for published studies that statistically test for a direct link between temperature and animal reproduction, in terms of fertility, fecundity or indirect measures of reproductive potential (gamete and gonad traits). 3. Overall, we collated a large and rich evidence base, with 1654 papers that met our inclusion criteria, encompassing 1191 species. 4. The map revealed several important research gaps. Insects made up almost half of the dataset, but reptiles and amphibians were uncommon, as were non‐arthropod invertebrates. Fecundity was the most common reproductive trait examined, and relatively few studies measured fertility. It was uncommon for experimental studies to test exposure of different life stages, exposure to short‐term heat or cold shock, exposure to temperature fluctuations, or to independently assess male and female effects. Studies were most often published in journals focusing on entomology and pest control, ecology and evolution, aquaculture and fisheries science, and marine biology. Finally, while individuals were sampled from every continent, there was a strong sampling bias towards mid‐latitudes in the Northern Hemisphere, such that the tropics and polar regions are less well sampled. 5. This map reveals a rich literature of studies testing the relationship between temperature and animal reproduction, but also uncovers substantial missing treatment of taxa, traits, and thermal regimes. This database will provide a valuable resource for future quantitative meta‐analyses, and direct future studies aiming to fill identified gaps.Publisher PDFPeer reviewe

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Systematic approaches to assessing high-temperature limits to fertility in animals

Critical thermal limits (CTLs) gauge the physiological impact of temperature on survival or critical biological function, aiding predictions of species range shifts and climatic resilience. Two recent Drosophila species studies, using similar approaches to determine temperatures that induce sterility (thermal fertility limits [TFLs]), reveal that TFLs are often lower than CTLs and that TFLs better predict both current species distributions and extinction probability. Moreover, many studies show fertility is more sensitive at less extreme temperatures than survival (thermal sensitivity of fertility [TSF]). These results present a more pessimistic outlook on the consequences of climate change. However, unlike CTLs, TFL data are limited to Drosophila, and variability in TSF methods poses challenges in predicting species responses to increasing temperature. To address these data and methodological gaps, we propose 3 standardized approaches for assessing thermal impacts on fertility. We focus on adult obligate sexual terrestrial invertebrates but also provide modifications for other animal groups and life-history stages. We first outline a “gold-standard” protocol for determining TFLs, focussing on the effects of short-term heat shocks and simulating more frequent extreme heat events predicted by climate models. As this approach may be difficult to apply to some organisms, we then provide a standardized TSF protocol. Finally, we provide a framework to quantify fertility loss in response to extreme heat events in nature, given the limitations in laboratory approaches. Applying these standardized approaches across many taxa, similar to CTLs, will allow robust tests of the impact of fertility loss on species responses to increasing temperatures