Predicting haemoglobin deferral using machine learning models: Can we use the same prediction model across countries?

BACKGROUND AND OBJECTIVES: Personalized donation strategies based on haemoglobin (Hb) prediction models may reduce Hb deferrals and hence costs of donation, meanwhile improving commitment of donors. We previously found that prediction models perform better in validation data with a high Hb deferral rate. We therefore investigate how Hb deferral prediction models perform when exchanged with other blood establishments. MATERIALS AND METHODS: Donation data from the past 5 years from random samples of 10,000 donors from Australia, Belgium, Finland, the Netherlands and South Africa were used to fit random forest models for Hb deferral prediction. Trained models were exchanged between blood establishments. Model performance was evaluated using the area under the precision-recall curve (AUPR). Variable importance was assessed using SHapley Additive exPlanations (SHAP) values. RESULTS: Across the validation datasets and exchanged models, the AUPR ranged from 0.05 to 0.43. Exchanged models performed similarly within validation datasets, irrespective of the origin of the training data. Apart from subtle differences, the importance of most predictor variables was similar in all trained models. CONCLUSION: Our results suggest that Hb deferral prediction models trained in different blood establishments perform similarly within different validation datasets, regardless of the deferral rate of their training data. Models learn similar associations in different blood establishments.

An international comparison of haemoglobin deferral prediction models for blood banking.

BACKGROUND AND OBJECTIVES: Blood banks use a haemoglobin (Hb) threshold before blood donation to minimize donors' risk of anaemia. Hb prediction models may guide decisions on which donors to invite, and should ideally also be generally applicable, thus in different countries and settings. In this paper, we compare the outcome of various prediction models in different settings and highlight differences and similarities. MATERIALS AND METHODS: Donation data of repeat donors from the past 5 years of Australia, Belgium, Finland, the Netherlands and South Africa were used to fit five identical prediction models: logistic regression, random forest, support vector machine, linear mixed model and dynamic linear mixed model. Only donors with five or more donation attempts were included to ensure having informative data from all donors. Analyses were performed for men and women separately and outcomes compared. RESULTS: Within countries and overall, different models perform similarly well. However, there are substantial differences in model performance between countries, and there is a positive association between the deferral rate in a country and the ability to predict donor deferral. Nonetheless, the importance of predictor variables across countries is similar and is highest for the previous Hb level. CONCLUSION: The limited impact of model architecture and country indicates that all models show similar relationships between the predictor variables and donor deferral. Donor deferral is found to be better predictable in countries with high deferral rates. Therefore, such countries may benefit more from deferral prediction models than those with low deferral rates.

Situation-specific outcomes (Home Situations Questionnaire) in a randomized controlled trial of individual versus group parent training for children with Hyperkinetic Disorder/Attention-deficit Hyperactivity Disorder.

OBJECTIVES: Assess (a) the variability of behaviour problems in children with Hyperkinetic Disorder/Attention-DeficitHyperactivity Disorder (HKD/ADHD) across a range of family situations and (b) the degree to which behaviour in each situation can be modified through a cognitive behavioural parent training (CBPT). Furthermore (c), compare the effectiveness of training in two different formats and (d) test the proposition that group treatment benefits behaviour in a wider range of situations than individual treatment. METHOD: A registered multicentre randomized controlled trial comparing individual and group parent training to treatment-as-usual (TAU) for N = 237 children with HKD/ADHD. A German version of the Home Situations Questionnaire (HSQ) was employed to examine behaviour problems across a range of family situations, treatment-related changes post-treatment and at 6-month follow-up, while controlling for medication status. RESULTS: Parents reported considerable variance in severity of behaviour problems across situations. All groups improved with time, but individual and group CBPT led to significantly greater improvement than TAU in many family situations. Results present situation-specific treatment trajectories and demonstrate somewhat greater impact of individual compared with group training in certain situations post-training and 6 months later. CONCLUSIONS: CBPT clearly adds to TAU (with effect sizes in the small to moderate range depending on situation). Individual was somewhat more successful than group format (which did not succeed in a wider range of situations). HSQ situations reveal a differentiated picture of child behaviour and treatment results. Situation-specific assessment with an instrument like the HSQ offers promising perspectives that invite further development.

Macronutrient content of pasteurised donor human milk: Variability between batches from single-donor pools at an Australian milk bank.

AIM: This study aimed to characterise the between-batch variability of pasteurised donor human milk (PDHM) produced from single-donor pools at Australian Red Cross Lifeblood's milk bank and identify key donor characteristics that predict macronutrient content. METHODS: Macronutrient content from 200 batches of PDHM was measured using a mid-infrared human milk analyser (Miris, Uppsala, Sweden). Linear mixed models were used to study the impact of stage of lactation and gestational age on macronutrient content. Coefficients of determination (R2 ) were calculated to estimate the impact of the individual donor on overall variability. RESULTS: Macronutrient content of PDHM varied considerably, with between-batch variations of 2.8 and 6.4-fold for protein and fat content, respectively. Mean crude protein content was 1.16 g/100 mL, ranging from 0.7 to 1.96 g/100 mL. Mean fat content was 3.85 g/100 mL, ranging from 1.46 to 9.39 g/100 mL. Stage of lactation was identified as a predictor for protein content and gestational age at birth for fat content. Individual donor effect explained 55 and 35% of the variance for fat and protein content, respectively. CONCLUSIONS: This study highlights the variation in macronutrient content in PDHM at an Australian milk bank. Variability could be reduced through the implementation of targeted multiple-donor pooling using the key donor characteristics identified in this study along with the measurement of macronutrient content of individual donors at the time of first donation. However, the clinical benefit of a reduction in between-batch variation, achieved through multiple-donor pooling, would need to be assessed to justify additional efforts associated with PDHM processing changes.

Predicting the unpredictable: analysing the entropy and spatial distribution of ball movement patterns in field hockey.

Analysing the ball movement patterns of team invasion sports provides practical insight into successful strategies by identifying how and where to move the ball to create goal scoring opportunities. The aim of this study was to analyse the entropy and spatial distribution of ball movement patterns in international field hockey teams. A notational analysis system was developed in SportsCode to analyse 131 matches (n = 57 men, n = 74 women) from the 2019 Pro League tournament. The start and end location of each ball movement and the outcome of each play was recorded. Calculated variables included game possession (%), entropy, possession per zone (%) and progression rates. Decision trees identified that higher circle possession and direct movements to goal from deep attack, and lower build attack and build defence entropy, were the strategies most likely to lead to goal shots. However, teams should be unpredictable when the opposition are organised to maintain possession and unbalance the defence. Match context only had small effects on ball movement strategies highlighting there is more than one way to be successful. Executing strategies that exploit these factors should lead to greater attacking opportunities and success. Analysing the dynamic, complexity of international hockey allows coaches to prepare specific strategies for individual teams.

Identifying and analysing game styles and factors influencing a team's strategy in field hockey.

Characterising a team's game style is a performance analysis approach that captures game events, and groups them into profiles using clustering techniques to identify the consistent (and winning) strategies a team implements. The aim of this study was to identify the game styles of international hockey teams. Video footage from the 2019 Pro League tournament (n = 74 female and n = 57 male matches) were analysed retrospectively using a notational analysis system in SportsCode™. Variables were arranged into six game style categories (established attack game actions, counter attack game actions, established attack success, counter attack success, set pieces, tempo) and two game style types identified per category using a k-means clustering algorithm. Decision trees were used to identify the influence of extrinsic and intrinsic match factors on the probability of a team playing a particular game style. Opposition and other reference team game style categories were shown to be more important in predicting a game style category than contextual factors. Examination of team profiles highlights how different strategies are successful for different teams such as high-intensity attack or absorbing pressure and counter attacking. This performance analysis process provides practical insights into the holistic performance of international hockey teams.

The impact of high-intensity interval training exercise on breast cancer survivors: a pilot study to explore fitness, cardiac regulation and biomarkers of the stress systems.

BACKGROUND: Cardiovascular disease (CVD) remains the largest cause of death in breast cancer survivors. The aim of this study was to explore the impact of exercise intensity on aerobic fitness and autonomic cardiac regulation (heart rate variability (HRV)) and salivary biomarkers of the stress systems (HPA-axis, cortisol; sympathetic nervous system, α-amylase) and mucosal immunity (secretory(s)-IgA), markers of increased risk of CVD in breast cancer survivors. METHODS: Participants were randomly assigned to; 1) high intensity interval training (HIIT); 2) moderate-intensity, continuous aerobic training (CMIT); or 3) a wait-list control (CON) for a 12-week (36 session) stationary cycling intervention. Cardiorespiratory fitness (VO2peak), resting HRV and salivary biomarkers were measured at baseline 2-4 d pre-intervention and 2-4 d post the last exercise session. RESULTS: Seventeen participants were included in this study (62 ± 8 years, HIIT; n = 6, CMIT; n = 5, CON; n = 6). A significant improvement (p ≤ 0.05) was observed for VO2peak in the HIIT group; 19.3% (B = 3.98, 95%CI = [1.89; 4.02]) and a non-significant increase in the CMIT group; 5.6% (B = 1.96, 95%CI = [- 0.11; 4.03]), compared with a 2.6% (B = - 0.64, 95%CI = [- 2.10; 0.82]) decrease in the CON group. Post intervention improvements in HRV markers of vagal activity (log (ln)LF/HF, LnRMSSD) and sympathetic nervous system (α-amylase waking response) occurred for individuals exhibiting outlying (> 95% CI) levels at baseline compared to general population. CONCLUSION: High intensity interval training improved cardiovascular fitness in breast cancer survivors and improved cardiac regulation, and sympathetic nervous system (stress) responses in some individuals. High-intensity interval training was safe and effective for breast cancer survivors to participate in with promising results as a time efficient intensity to improve physical health and stress, reducing CVD risk. TRIAL REGISTRATION: This pilot study was retrospectively registered through the Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12620000684921 .

Key viral immune genes and pathways identify elite athletes with URS.

PURPOSE: Habitual intense exercise may increase the incidence of upper respiratory symptoms (URS) in elite athletes. This study investigated whether immune gene expression could identify gene markers that discriminate athletes with a higher prevalence of URS. METHODS: This cross-sectional analysis of elite Australian athletes from various sports investigated whether athletes retrospectively reporting URS for two days or more in a month (n=38), had an altered immune gene expression profile compared with asymptomatic athletes (n=33). Peripheral blood samples were collected during Olympic selection events with corresponding URS data collected for the one-month period before sampling. Digital immune gene expression analysis was undertaken using the NanoString PanCancer Immune Profiling panel. RESULTS: Fifty immune genes were differentially expressed between the groups (p<0.05) and approximately 78% of these genes were more highly expressed in athletes reporting URS. Many of these genes were interferon-stimulated genes or genes involved in the Jak/Stat signalling pathway. Only interferon alpha inducible protein 27 (IFI27), an interferon stimulated gene involved in viral response, remained significantly higher in athletes reporting URS (log2 fold-difference=2.49, odds ratio 1.02 per unit increase; p<0.01) post-adjustment and discriminated athletes reporting URS from asymptomatic athletes with 78% accuracy. CONCLUSIONS: Expression of IFI27 could differentiate athletes reporting URS from asymptomatic athletes, a gene that is upregulated in the immune response to viral infection. Upregulation of viral signalling pathways provides novel information on the potential aetiology of URS in elite Olympic athletes.

Glucocorticoid prescribing habits of sports medicine physicians working in high-performance sport: a 30-nation survey.

OBJECTIVES: Glucocorticoids are commonly prescribed in medicine. When administered via certain routes, glucocorticoids are prohibited for incompetition use by WADA. The glucocorticoid prescribing habits of sports medicine doctors have not been reported. METHODS: An online survey was distributed internationally to physicians working in high-performance sports. The survey queried the doctors about their use of glucocorticoids with athletes and their understanding of WADA's regulations regarding glucocorticoid use in competition. RESULTS: 603 sports medicine doctors from 30 different countries participated. The majority (>85%) routinely injected glucocorticoids and/or prescribed glucocorticoids by other routes. There were substantial differences in the common routes of injection as well as types of glucocorticoid used among the physicians from various countries. A relatively small percentage of sports doctors (<25%) accurately identified which routes of glucocorticoid administration are prohibited in competition by WADA. There was a great variation in how long before competition the use of glucocorticoids would cause the doctor to consider applying for a therapeutic use exemption (TUE). A better understanding of the clearance rates of glucocorticoids from athletes' bodies would greatly aid sports medicine doctors' decisions on how and when to apply for a TUE. A small number of doctors had observed side effects of glucocorticoid administration, with the majority of side effects being minor in nature. CONCLUSION: Glucocorticoids are widely prescribed by sports physicians. There is a need to better educate sports physicians on the current WADA regulations in relation to glucocorticoid administration.

Methods of performance analysis in team invasion sports: A systematic review.

The objective of this review was to systematically describe the traditional and contemporary data capture and analytic methods employed in performance analysis research in team invasion sports, evaluate the practicality of these methods, and formulate practical recommendations on methods for analysing tactics and strategies in team invasion sports. A systematic search of the databases SPORTDiscus, Web of Science, Scopus, MEDLINE and PubMed was performed. Keywords addressed performance analysis methods and team invasion sports, with all other disciplines of sports science excluded. A total of 537 articles were included in the review and six main themes of research identified. Themes included game actions, dynamic game actions, movement patterns, collective team behaviours, social network analysis and game styles. Performance analysis research has predominantly focused on identifying key performance indicators related to success by analysing differences in game actions between successful and less successful teams. However, these measures are outcome-focused and only provide limited insight into winning team's strategy. Team invasion sports are now viewed as dynamic, complex systems with opposing teams as interacting parts. Strategies and tactics should be analysed using a holistic process-orientated approach by recording dynamic actions, collective team behaviours and passing networks, and viewing them in game styles.

Adding Telephone and Text Support to an Obesity Management Program Improves Behavioral Adherence and Clinical Outcomes. A Randomized Controlled Crossover Trial.

BACKGROUND: Behavioral treatment strategies improve adherence to lifestyle intervention for adults with obesity, but can be time and resource intensive when delivered via traditional face-to-face care. This study aimed to investigate the efficacy and optimal timing of using telephone calls and text message as adjunctive tools to support a community-based obesity management program. METHOD: This 8-month randomized controlled crossover trial recruited 61 adults with class III obesity (BMI > 40 kg/m2) enrolled in a publicly funded obesity management service (OMS). Participants were randomly assigned to receive telephone and text message support in addition to standard OMS care, or standard OMS care alone. After 4 months, participants crossed over to the alternative sequence. The technological support was based on self-determination theory. Outcome measures included diet, physical activity, anthropometry, self-efficacy, and treatment self-regulation. RESULTS: Telephone and text message support improved lifestyle intervention adherence and clinical outcomes when compared with standard care. Participants who received the intervention in the first 4-month period lost 4.87 kg, compared with no weight loss (+ 0.38 kg) in the standard care only group. There was no evidence to indicate an optimal timing of the intervention, with both groups achieving significant results by the end of the intervention. CONCLUSION: These results suggest a high degree of promise for the incorporation of telephone and text message support into community-based obesity management services. The findings have the potential to improve existing practices and reduce the burden on the health care system by demonstrating a resource-effective improvement to obesity management service delivery.

Urinary Hydroxyproline Is Only Suitable As a Biomarker for Acute Intake, Up to 6 hr Postingestion of Collagen Proteins in "Free-Living," Healthy, Active Males.

The urinary excretion of hydroxyproline (Hyp), abundant in collagen protein, may serve as a biomarker of habitual collagen intake, assisting with investigations of current interest in the role of dietary collagen intake in supporting the synthesis of collagenous body tissues. This study investigated the time course of urinary Hyp excretion in "free-living," healthy, active males following the ingestion of a standardized bolus (20 g) of collagenous (gelatin and a hydrolyzed collagen powder) and dairy (calcium caseinate and hydrolyzed casein) proteins. The excretion of Hyp was assessed over a 24-hr period, separated into three collection periods: 0-6, 6-12, and 12-24 hr. Hyp was elevated for 0-6 hr after the consumption of collagen-containing supplements (gelatin 31.3 ± 8.8 mmol/mol and hydrolyzed collagen 33.7 ± 22.0 mmol/mol vs. baseline: gelatin 2.4 ± 1.7 mmol/mol and hydrolyzed collagen 2.8 ± 1.5 mmol/mol; p < .05), but not for the dairy protein supplements (calcium caseinate 3.4 ± 1.7 mmol/mol and hydrolyzed casein 4.0 ± 3.7 mmol/mol; p > .05). Therefore, urinary Hyp reflects an acute intake of collagenous protein, but is not suitable as a biomarker for quantifying habitual collagen intake, provided through regular dietary practices in "free-living," healthy, active males.

Prevalence of illness, poor mental health and sleep quality and low energy availability prior to the 2016 Summer Olympic Games.

OBJECTIVE: Establish the prevalence of illness symptoms, poor sleep quality, poor mental health symptoms, low energy availability and stress-recovery state in an Olympic cohort late in the 3 months prior to the Summer Olympic Games. METHODS: Olympic athletes (n=317) from 11 sports were invited to complete questionnaires administered 3 months before the Rio 2016 Olympic Games. These questionnaires included the Depression, Anxiety and Stress Questionnaire, Perceived Stress Scale, Dispositional Resilience Scale, Recovery-Stress Questionnaire (REST-Q-52 item), Low Energy Availability in Females Questionnaire (LEAF-Q), Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index and custom-made questionnaires on probiotic usage and travel. Multiple illness (case) definitions were applied. ORs and attributable fractions in the population were used. Factor analyses were used to explore the relationships between variables. RESULTS: The response rate was of 42% (male, n=47, age 25.8±4.1 years; female, n=85, age 24.3±3.9 years). Low energy availability was associated with sustaining an illness in the previous month (upper respiratory, OR=3.8, 95% CI 1.2 to 12). The main factor relating to illness pertained to a combination of anxiety and stress-recovery states (as measured by the REST-Q-52 item). All participants reported at least one episode of illness in the last month (100% prevalence). CONCLUSIONS: All participants reported at least one illness symptom in the previous month. Low energy availability was a leading variable associated with illness in Olympic-class athletes. The estimates duration of symptoms ranged from 2 to 7 days. Factor analyses show the interdependence of various health domains and support multidisciplinary care.

The effects of football match congestion in an international tournament on hip adductor squeeze strength and pain in elite youth players.

The purpose of this study was to investigate the effect of a congested international tournament match schedule on adductor strength and pain in elite youth football players. Twenty-two male players (age: 15.53 ± 0.48 years, height: 174.87 ± 7.59 cm, weight: 67.45 ± 7.40 kg) were included. The 5-second adductor squeeze strength was captured daily using a hand-held dynamometer during a 7-game international tournament. Pain during the squeeze test was recorded using numerical pain ratings (0-10) to quantify groin pain. Sessional rate of perceived exertion (sRPE) was collected during the tournament. Adductor strength changed significantly during the tournament in relation to time (F(14,294.94) = 1.89, p = 0.027) and cumulative sRPE (F(1,314) = 5.59, p = 0.019). Cumulative sRPE displayed a negative relationship with strength (B = -0.008, SE = 0.0032, 95%CI = -0.014,-0.002). The results indicate that for every 100 match sRPE arbitrary units the squeeze peak force reduced by 0.8N. Sixteen (72.7%) players demonstrated clinically meaningful strength reductions (>15%) during the tournament. Match congestion impacts on hip adductor squeeze strength in male youth football players. A negative relationship between match sRPE and adductor strength exists. Player monitoring involving the 5-second adductor squeeze test can be captured effectively and is suitable to include as part of secondary injury prevention during or immediately after a congested tournament.

Low carbohydrate, high fat diet impairs exercise economy and negates the performance benefit from intensified training in elite race walkers.

KEY POINTS: Three weeks of intensified training and mild energy deficit in elite race walkers increases peak aerobic capacity independent of dietary support. Adaptation to a ketogenic low carbohydrate, high fat (LCHF) diet markedly increases rates of whole-body fat oxidation during exercise in race walkers over a range of exercise intensities. The increased rates of fat oxidation result in reduced economy (increased oxygen demand for a given speed) at velocities that translate to real-life race performance in elite race walkers. In contrast to training with diets providing chronic or periodised high carbohydrate availability, adaptation to an LCHF diet impairs performance in elite endurance athletes despite a significant improvement in peak aerobic capacity. ABSTRACT: We investigated the effects of adaptation to a ketogenic low carbohydrate (CHO), high fat diet (LCHF) during 3 weeks of intensified training on metabolism and performance of world-class endurance athletes. We controlled three isoenergetic diets in elite race walkers: high CHO availability (g kg-1  day-1 : 8.6 CHO, 2.1 protein, 1.2 fat) consumed before, during and after training (HCHO, n = 9); identical macronutrient intake, periodised within or between days to alternate between low and high CHO availability (PCHO, n = 10); LCHF (< 50 g day-1 CHO; 78% energy as fat; 2.1 g kg-1  day-1 protein; LCHF, n = 10). Post-intervention, V̇O2 peak during race walking increased in all groups (P < 0.001, 90% CI: 2.55, 5.20%). LCHF was associated with markedly increased rates of whole-body fat oxidation, attaining peak rates of 1.57 ± 0.32 g min-1 during 2 h of walking at ∼80% V̇O2 peak . However, LCHF also increased the oxygen (O2 ) cost of race walking at velocities relevant to real-life race performance: O2 uptake (expressed as a percentage of new V̇O2 peak ) at a speed approximating 20 km race pace was reduced in HCHO and PCHO (90% CI: -7.047, -2.55 and -5.18, -0.86, respectively), but was maintained at pre-intervention levels in LCHF. HCHO and PCHO groups improved times for 10 km race walk: 6.6% (90% CI: 4.1, 9.1%) and 5.3% (3.4, 7.2%), with no improvement (-1.6% (-8.5, 5.3%)) for the LCHF group. In contrast to training with diets providing chronic or periodised high-CHO availability, and despite a significant improvement in V̇O2 peak , adaptation to the topical LCHF diet negated performance benefits in elite endurance athletes, in part due to reduced exercise economy.

Developing a multivariate prediction model of falls among older community-dwelling adults using measures of neuromuscular control and proprioceptive acuity: A pilot study.

OBJECTIVE: To examine whether measures of neuromuscular control and proprioceptive acuity were predictive of falls in an older community-dwelling population and to develop a multivariate prediction model. METHODS: Fifty-eight adults aged above 60 living independently in the community were recruited for a prospective falls study. On entry, they undertook a Sensory Organisation Test (SOT) and an Active Movement Extent Discrimination Assessment (AMEDA) and completed a short fall risk questionnaire. Participants were monitored for falls over the subsequent 12 months. Prior to analysis, falls were classified into three categories based on the difficulty of the activity being undertaken and the demands of the environment in which the fall occurred. Logistic regression was used to predict the probability of a fall. RESULTS: For falls occurring under the least challenging circumstances, the model fitted using the AMEDA score and two of the questions from the fall risk questionnaire, related to balance and confidence, achieved a specificity of 87% and sensitivity of 83%. Falls occurring in more challenging circumstances could not be predicted with any accuracy based on the variables recorded at inception. CONCLUSIONS: This study highlights the importance of considering the heterogeneous nature of falls. Poorer proprioceptive acuity appears to play a role in falls occurring where neither the environment nor the activity is challenging, but not in falls occurring in other circumstances. Falls in the least-challenging circumstances affected 15% of participants, but this group was considerably more likely to have multiple falls, increasing their vulnerability to adverse consequences.

Next generation sequencing to identify iron status and individualise blood donors' experience.

BACKGROUND: Young adults form the majority of first-time blood donors to Australian Red Cross Lifeblood. However, these donors pose unique challenges for donor safety. Young blood donors, who are still undergoing neurological and physical development, have been found to have lower iron stores, and have higher risks of iron deficiency anaemia when compared to older adults and non-donors. Identifying young donors with higher iron stores may improve donor health and experience, increase donor retention, and reduce the burden on product donation. In addition, these measures could be used to individualise donation frequency. MATERIALS AND METHODS: Stored DNA samples from young male donors (18-25 years; No.=47) were sequenced using a custom panel of genes identified in the literature to be associated with iron homeostasis. The custom sequencing panel used in this study identified and reported variants to human genome version 19 (Hg19). RESULTS: 82 gene variants were analysed. Only one of which, rs8177181, was found to have a statistically significant (p<0.05) association with plasma ferritin level. Heterozygous alleles of this Transferrin gene variant, rs8177181T>A, significantly predicted a positive effect on ferritin levels (p=0.03). DISCUSSION: This study identified gene variants involved in iron homeostasis using a custom sequencing panel and analysed their association with ferritin levels in a young male blood donor population. Additional studies of factors associated with iron deficiency in blood donors are required if a goal of personalised blood donation protocols is to be achieved.

Capture, analyse, visualise: An exemplar of performance analysis in practice in field hockey.

The goal of performance analysis is to capture the multitude of factors that affect sports strategy, and present them in an informative, interpretable, and accessible format. The aim of this study was to outline a performance analysis process in field hockey that captures, analyses and visualises strategy in layers of detail culminating in the creation of an RStudio Shiny application. Computerised notational analysis systems were developed to capture in-game events and ball tracking data of 74 matches from the Women's Pro League 2019. Game styles were developed using k-means cluster analysis to reduce detailed in-game events into practical profiles to identify the attack types, game actions and tempo of a team's strategy. Ball movement profiles were developed to identify the predictability (entropy) and direction (progression rates) of ball movements, and consequent distribution of possession in different attacking zones. The Shiny application, an interactive web-platform, links the information from simple game profiles with detailed game variables to understand each teams' holistic game plan, how they are different, and how to exploit these differences. The process outlined can be applied to any team invasion sport to understand, develop and communicate successful strategies under different match situations.

Daily surveillance of falls is feasible and reveals a high incidence of falls among older adults.

OBJECTIVE: To ensure accurate data capture for a fall study through a system of daily contact with participants. METHODS: Fifty-eight adults older than 60 years of age and living independently in the community in Canberra, Australia, were recruited for a prospective fall study. We adopted a system of daily contact with study participants for at least 12 months, either by email or by text, asking whether they had suffered a fall in the previous 24 h. At the final testing session, we asked participants whether they had experienced a fall during the previous twelve months. RESULTS: We found no evidence that the daily reporting regime led to excess participant attrition. Only three participants withdrew over the course of the study, and the burden of responding was not cited as a factor in any of these cases. Of the 55 participants who completed the full twelve-month study period, 38 (69%) experienced at least one fall. We also identified inconsistencies between recall of falls occurring during the last twelve months of the study and the contemporaneously recorded data. CONCLUSIONS: Previous studies have found that increasing the reporting demands on fall study participants will lead to higher attrition. This study demonstrates that it is possible to maintain participant engagement and minimise attrition with appropriate design of reporting procedures. We confirm existing evidence regarding the unreliability of retrospective recall of falls. The study highlights the importance of comprehensive and accurate data capture and points to the possibility of under-reporting of fall incidence.

Stressed and Not Sleeping: Poor Sleep and Psychological Stress in Elite Athletes Prior to the Rio 2016 Olympic Games.

PURPOSE: Psychological stress is reported to be an important contributor to reduced sleep quality and quantity observed in elite athletes. The purpose of this study was to explore the association between psychological stress and sleep and to identify if specific aspects of sleep are disturbed. METHODS: One hundred thirty-one elite athletes (mean [SD], male: n = 46, age 25.8 [4.1] y; female: n = 85, age 24.3 [3.9] y) from a range of sports completed a series of questionnaires in a 1-month period approximately 4 months before the 2016 Rio Olympic Games. Questionnaires included the Pittsburgh Sleep Quality Index; Recovery-Stress Questionnaire; Depression, Anxiety, and Stress Scale (DASS 21); and Perceived Stress Scale (PSS). RESULTS: Regression analysis identified the PSS and DASS stress as the main variables associated with sleep. A PSS score of 6.5 or higher was associated with poor sleep. In addition, a PSS score lower than 6.5 combined with a DASS stress score higher than 4.5 was also associated with poor sleep. Univariate analyses on subcomponents of the Pittsburgh Sleep Quality Index confirmed that PSS is associated with lower sleep quality (t99 = 2.40, P = .018), increased sleep disturbances (t99 = 3.37, P = .001), and increased daytime dysfunction (t99 = 2.93, P = .004). DASS stress was associated with increased sleep latency (t94 = 2.73, P = .008), increased sleep disturbances (t94 = 2.25, P = .027), and increased daytime dysfunction (t94 = 3.58, P = .001). CONCLUSIONS: A higher stress state and higher perceived stress were associated with poorer sleep, in particular increased sleep disturbances and increased daytime dysfunction. Data suggest that relatively low levels of psychological stress are associated with poor sleep in elite athletes.