Validity of a squash-specific test of change-of-direction speed

Purpose: We examined the validity and reproducibility of a squash-specific test designed to assess change-of-direction speed. Methods: 10 male squash and 10 male association-football and rugby-union players completed the Illinois agility run (IAR) and a squash change-of-direction-speed test (SCODS) on separate days. Tests were repeated after 24 h to assess reproducibility. The best time from three attempts was recorded in each trial. Results: Performance times on the IAR (TE 0.27 s, 1.8%, 90% CI 0.21 to 0.37 s; LOA −0.12 s ± 0.74; LPR slope 1, intercept −2.8) and SCODS (TE 0.18 s, 1.5%, 90% CI 0.14 to 0.24 s; LOA 0.05 s ± 0.49; LPR slope 0.95, intercept 0.5) were reproducible. There were no statistically significant differences in performance time between squash (14.75 ± 0.66 s) and nonsquash players (14.79 ± 0.41 s) on the IAR. Squash players (10.90 ± 0.44 s) outperformed nonsquash players (12.20 ± 0.34 s) on the SCODS (P < .01). Squash player rank significantly correlated with SCODS performance time (Spearman’s ρ = 0.77, P < .01), but not IAR performance time (Spearman’s ρ = 0.43, P = .21). Conclusions: The results suggest that the SCODS test is a better measure of sport-specific capability than an equivalent nonspecific field test and that it is a valid and reliable tool for talent identification and athlete tracking

Reproducibility of physiological and performance measures from a squash-specific fitness test

Purpose We examined the reproducibility of performance and physiological responses on a squash-specific incremental test. Methods Eight trained squash players habituated to procedures with two prior visits performed an incremental squash test to volitional exhaustion on two occasions 7 days apart. Breath-by-breath oxygen uptake (Vo2) and heart rate were determined continuously using a portable telemetric system. Blood lactate concentration at the end of 4-min stages was assessed to determine lactate threshold. Once threshold was determined, test speed was increased every minute until volitional exhaustion for assessment of maximal oxygen uptake (Vo2max), maximum heart rate (HRmax), and performance time. Economy was taken as the 60-s mean of Vo2 in the final minute of the fourth stage (below lactate threshold for all participants). Typical error of measurement (TEM) with associated 90% confidence intervals, limits of agreement, paired sample t tests, and least products regression were used to assess the reproducibility of scores. Results Performance time (TEM 27 s, 4%, 90% CI 19 to 49 s) Vo2max (TEM 2.4 mL·kg−1·min−1, 4.7%, 90% CI 1.7 to 4.3 mL·kg−1·min−1), maximum heart rate (TEM 2 beats·min−1, 1.3%, 90% CI 2 to 4 beats·min−1), and economy (TEM 1.6 mL·kg−1·min−1, 4.1%, 90% CI 1.1 to 2.8 mL·kg−1·min−1) were reproducible. Conclusions The results suggest that endurance performance and physiological responses to a squash-specific fitness test are reproducible

Transient nuclear criticality analysis of aqueous fissile solutions using point nuclear reactor kinetics and phenomenological thermal-hydraulic feedback models

This thesis presents a range of mathematical and computational models for use in transient nuclear criticality safety assessment. A mathematical model for quantifying the uncertainty in the wait-time probability distributions of criticality excursions initiated in the presence of weak intrinsic neutron sources is presented. This model is used to demonstrate the potential influence of parametric uncertainty on the wait-time probability distributions of the 1958 Y-12 criticality accident and experiments on the Caliban reactor. Also presented in this thesis is a new mathematical and computational model of radiolytic gas production and evolution in fissile liquids. This model has been validated against nuclear criticality safety benchmark experiments on fissile solution reactors and has been shown to accurately predict features of the fission power profiles related to the appearance and advection of radiolytic gas voids in the solution. The model has also demonstrated efficacy in predicting the timing and magnitude of secondary peaks in the fission power output. The purpose of this new mathematical and computational radiolytic gas model was to improve the simulation of fissile liquid criticality transients while removing the need for the adjustable heuristic parameters used by existing fissile liquid simulation codes. These parameters, which must be appropriately adjusted to criticality safety benchmark experiments, are dependent on the geometry and composition of the system being analysed. The need for these heuristic parameters therefore precludes the use of these codes as predictive modelling and simulation tools. The new mathematical and computational model, presented in this thesis, offers valuable insights into the behaviour of radiolytic gas in fissile liquid systems.Open Acces

On the Development of Analytical Methodologies to Interrogate the Lipid Dynamics and Phase Transition Resulting from the Reduction of Stimuli-responsive Vesicles

The potential is great for liposome drug delivery systems that provide specific contents release at diseased tissue sites upon activation by upregulated enzymes; however, this potential will only come to fruition with mechanistic knowledge of the contents release process. NAD(P)H:quinone oxidoreductase type 1 (NQO1) is a target for reductively-responsive liposomes, as it is an enzyme upregulated in numerous cancer tissues and is capable of reducing quinone propionic acid (QPA) trigger groups to hydroquinones that self-cleave from dioleolylphosphatidylethanolamine (DOPE) liposome surfaces, thereby initiating contents release. This research targets the development of analytical methodologies to observe and characterize the dynamics and resulting phase change of the QPA-DOPE liposomal system. It is known that after reduction, QPA-DOPE vesicles aggregate and that the aggregation is correlated with release of their encapsulated contents. While postulated, the final phase identity of this system has not been identified as the conventional methods used to make this measurement are not capable of studying such a unique and dynamic system. Presented herein are the analytical methods, both developed and adapted, which have been used to investigate a liposomal system capable of redox stimulated contents release. The purpose of this work was to utilize these tools to (1) study the terminal phase identity of QPA-DOPE vesicles after reduction, (2) manipulate the QPA-DOPE liposomal system for triggerable inter-vesical fusion, and (3) investigate the liposome bilayer behavior post-reduction and pre-release. The findings of this work are presented and their significance discussed

The Effectiveness of a Leg-Kicking Training Program on Performance and Physiological Measures of Competitive Swimmers

This study investigated the adaptations in leg muscle metabolism of swimmers following a six-week, leg-kicking swimming training program Fifteen male competitive swimmers were randomly assigned to an experimental group (E; n=8) and a control group (C; n=7). E swimmers performed normal leg-kicking training three times per week, whereas C swimmers performed reduced leg-kicking training (20% and 4% of weekly training distance, respectively). Before and after the training program, all swimmers performed a 200 m leg-kicking and a 400 m full-stroke freestyle time trial and a dry-land exercise test during which peak oxygen uptake, oxygen uptake at 60 W and exercise intensity at ventilatory threshold were measured. After training, there were improvements in leg-kicking time in 200 m (s; −6.0 ± 2.0%, p = 0.044), oxygen uptake at 60 Watts (L·min−1; −20.4 ± 3.0%, p = 0.035) and exercise intensity at ventilatory threshold (Watts; +28.0 ± 5.0%, p = 0.023) in E swimmers, whereas time in 400 m and peak oxygen uptake remained unchanged (p > 0.05). There were no changes in any of the measures for C swimmers (P > 0.05). These results suggest that normal leg-kicking swimming training positively affects the conditioning of the legs, but does not improve aerobic power during the dry-land, leg-kicking exercise test or middle-distance, full-stroke, swimming performance

Towards an Epistemology for Action-Research

Action-research's epistemological problem is that it proposes an opposition to positivist forms of social inquiry while implicitly using a positivist epistemology to justify its own procedures. This work is an attempt to formulate an alternative epistemology for action-research. A selection of action-research writing is critically reviewed in order to show the lacunae and inconsistencies which necessitate a more thoroughly argued theoretical framework. This alternative epistemology is based on a reflexive theory of consciousness and language, and on a dialectical theory of the self-other relationship. In this way it proposes the possibility of a theorizing Subject, and in particular its specific autonomy in relation to theories of ideology and of societal and psychoanalytic determinism. The argument has the following stages. Chapter One introduces the general theme. Chapter Two analyzes the relationship between action and research, not as a process of evaluation or prescription, but as a dialectic of reflexive and critical questioning. Chapter Three critically considers theories of the self and of the unconscious in order to formulate the possibility of critical self-reflection. Chapter Four analyzes the social relationships of the research process, criticizing the Habermasian notion of -emancipation", and analysing the relationship between criteria for the improvement of professional practice and the criteria for adequate research, including a consideration of how action-research might relate to the processes of professionalized institutions. This section involves an analysis of theories of professionalism and bureaucracy. In Chapter Five the argument turns more generally to the forms of validity to which action-research might aspire, criticizing such notions as "naturalistic theory" and "illumination", and formulating validity in terms of reflexivity and dialectics. In this context, also, action-research attempts to invoke "aesthetic" modes of understanding are considered, and a contrast is drawn between action-research's reliance on forms of representational realism and reflexive theories of textual structure and response. Chapter Six, the conclusion, draws together the foregoing arguments in order to present six critical propositions, as a set of implications for the renewed practice of action-research

Physiological correlates of performance in international-standard squash players

Tactical, technical and fitness factors are important for success in elite squash. While tactical and endurance fitness aspects have been explored, altered demands that have resulted from rule changes and absence of specific tests of high-intensity exercise capabilities have prevented identification of elements of fitness that correlate with performance in elite-standard players. Accordingly, the purpose of this study was to investigate relationships between test scores and player rank in such players. With institutional ethics approval, 31 players from the England Squash performance programme participated (11 women and 20 men, mean±SD body mass 62.4±5.5 kg and 73.1±7.5 kg respectively). After habituation, participants completed countermovement and drop-jump tests, squash-specific tests of change-of-direction speed and multiple-sprint ability and the multistage fitness test in one test session. Short recoveries were allowed between tests. World rank at the time of testing was obtained from the Professional Squash Association website. In men, change-of-direction speed (??=?0.59, p?=?0.02, n?=?14) multiple-sprint ability (??=?0.78, p<0.01, n?=?13) and fastest sprint from the multiple-sprint test (??=?0.86, p<0.01, n?=?13) correlated with world rank. In women, only fastest repetition from the multiple-sprint test correlated with world rank (??=?0.65, p?=?0.04, n?=?10). Measures of high-intensity exercise capability correlated with world rank in elite-standard men and women players. Endurance capability did not relate to rank in either the men or women. The results suggest that high-intensity, variable-direction exercise capabilities are important for success in elite squash

The meiosis-specific Cdc20 family-member Ama1 promotes binding of the Ssp2 activator to the Smk1 MAP kinase.

Smk1 is a meiosis-specific MAP kinase (MAPK) in budding yeast that is required for spore formation. It is localized to prospore membranes (PSMs), the structures that engulf haploid cells during meiosis II (MII). Similar to canonically activated MAPKs, Smk1 is controlled by phosphorylation of its activation-loop threonine (T) and tyrosine (Y). However, activation loop phosphorylation occurs via a noncanonical two-step mechanism in which 1) the cyclin-dependent kinase activating kinase Cak1 phosphorylaytes T207 during MI, and 2) Smk1 autophosphorylates Y209 as MII draws to a close. Autophosphorylation of Y209 and catalytic activity for substrates require Ssp2, a meiosis-specific protein that is translationally repressed until anaphase of MII. Ama1 is a meiosis-specific targeting subunit of the anaphase-promoting complex/cyclosome that regulates multiple steps in meiotic development, including exit from MII. Here, we show that Ama1 activates autophosphorylation of Smk1 on Y209 by promoting formation of the Ssp2/Smk1 complex at PSMs. These findings link meiotic exit to Smk1 activation and spore wall assembly

Considerations for the scientific support process and applications to case studies

Case studies are vehicle to bridge the gap between science and practice because they provide opportunities to blend observations and interventions that have taken place in real-world environments with scientific rigour. The purpose of this invited commentary is to present considerations for those providing applied sport science support to athletes with the intention of broadcasting this information to the scientific community. We present a four phased approach (1: Athlete overview; 2: Needs analysis; 3: Intervention planning; 4: Results,evaluation and conclusion) for scientific support to assist practitioners in the development and implementation of scientific support. These considerations are presented in the form of ‘performance questions’ designed to guide and critically evaluate the scientific support process and aid the transfer of this knowledge via case studies