Analysis of styles of play according to season and end of season rank in the National Rugby League.

OBJECTIVES: This study aimed to identify styles of play in the National Rugby League (NRL) relative to season and end of season rank (position on the NRL ladder) across the 2015-2019 seasons. DESIGN: Retrospective, longitudinal analysis of performance indicators. METHODS: Forty-eight performance indicators (e.g. runs, tackles) from all NRL teams and matches during the 2015-2019 seasons (n=2010) were quantified. Principal component analysis (PCA) was then used to identify styles of play based on dimensions (Factors) of performance indicators. Multivariate analysis of covariance (MANCOVA) was then used to explain these emergent styles of play relative to 'season' and 'end of season rank'. RESULTS: The PCA revealed nine Factors (six attacking, two defensive and one contested style) accounting for ∼51% of seasonal team performance variance. These nine Factors differed across 'seasons', with four showing an effect against 'end of season rank'. From these four, two Factors (ball possession and player efforts) impacted upon the combined effects of 'season' and 'end of season rank'. CONCLUSIONS: The PCA identified nine Factors reflecting a spread of attacking, defensive and contested styles of play within the NRL. These styles differed relative to season and a team's end of season ranking. These results may assist practitioners with the recognition of more contemporary styles of play in the NRL, enabling the development of strategies to exploit competition trends.

Examining the evolution and classification of player position using performance indicators in the National Rugby League during the 2015-2019 seasons.

OBJECTIVES: This study aimed to: 1) examine recent seasonal changes in performance indicators for different National Rugby League (NRL) playing positions; and 2) determine the accuracy of performance indicators to classify and discriminate positional groups in the NRL. DESIGN: Retrospective, longitudinal analysis of individual performance metrics. METHODS: 48 performance indicators (e.g. passes, tackles) from all NRL games during the 2015-2019 seasons were collated for each player´s match-related performance. The following analyses were conducted with all data: (i) one-way ANOVA to identify seasonal changes in performance indicators; (ii) principal component analysis (PCA) to group performance indicators into factors; (iii) two-step cluster analysis to classify playing positions using the identified factors; and (iv) discriminant analysis to discriminate the identified playing positions. RESULTS: ANOVA showed significant differences in performance indicators across seasons (F=2.3-687.7; p=0-0.05; partial η2=0.00-0.075). PCA pooled all performance indicators and identified 14 factors that were included in the two-step cluster analysis (average silhouette=0.5) that identified six positional groups: forwards, 26.7%, adjustables, 17.2%, interchange, 23.2%, backs, 20.9%, interchange forwards, 5.5% and utility backs, 6.5%. Lastly, discriminant analysis revealed five discriminant functions that differentiated playing positions. CONCLUSIONS: Results indicated that player's performance demands across different playing positions did significantly change over recent seasons (2015-2019). Cluster analysis yielded a high-level of accuracy relative to playing position, identifying six clusters that best discriminated positional groups. Unsupervised analytical approaches may provide sports scientists and coaches with meaningful tools to evaluate player performance and future positional suitability in RL.

Predictive modelling of the physical demands during training and competition in professional soccer players.

OBJECTIVES: The present study aimed to predict the cut-off point-values that best differentiate the physical demands of training and competition tasks including friendly matches (FM), small sided games (SSG), large sided games (LSG), mini-goal games (MG) and ball circuit-training (CT) in professional soccer players. DESIGN: Experimental randomized controlled trial. METHODS: Fourteen professional players participated in all tasks with the CT, SSG and MG consisting of 8 repetitions of 4-min game play, interspersed by 2-min of active recovery. The training data were compared to the first 32-min of the LSG and two competitive FM per player. All movement patterns from walking to sprint running were recorded using 10Hz GPS devices while player perception of exertion was recorded via a visual analogue scale, post-task. Decision tree induction was applied to the dataset to assess the cut-off point-values from four training drills (SSG, LSG, MG, and CT) and FM for every parameter combination. RESULTS: Distance covered during jogging (2.3-3.3m/s; >436m), number of decelerations (≤730.5) and accelerations (≤663), and maximum velocity reached (>5.48m/s) characterized the physical demands during competition (FM) with great variability amongst training drills. CONCLUSION: The use of these novel, cut-off points may aid coaches in the design and use of training drills to accurately prepare athletes for soccer competition.

A Single Bout of Arm-crank Exercise Promotes Positive Emotions and Post-Exercise Hypotension in Patients with Symptomatic Peripheral Artery Disease.

OBJECTIVE/BACKGROUND: The objective was to analyze the acute effects of a single bout of arm cranking exercise on affective and cardiovascular parameters in patients with symptomatic peripheral artery disease (PAD). METHODS: This was a prospective, controlled, crossover study. Eleven men with symptomatic PAD underwent two experimental sessions in a random order: control or arm crank exercise (15 × 2 minutes bouts of arm crank exercise interrupted by 2 minutes rest intervals). During exercise, ratings of perceived exertion (Borg scale) and affective responses (pleasure/displeasure) were obtained at the first, fifth, tenth, and fifteenth bouts. Before and after the experimental sessions, cardiovascular parameters (blood pressure and heart rate) were obtained. Data were analysed by a two-way repeated measure analysis of variance with significance achieved at p < .05. RESULTS: During the arm crank exercise, patients reported positive feelings of pleasure. During exercise, heart rate (HR) remained within 80-90% of peak HR. Additionally, patients performed arm crank exercise with moderate levels of perceived exertion (Borg rating of 11-13) and with pleasant affective scores (Feeling Scale of +1 to +5). Blood pressure (systolic, diastolic, and mean) increase was lower after arm crank exercise than for control (greatest net effect: -15 ± 11 mmHg [p < .001]; -9 ± 5 mmHg [p < .001]; -9 ± 6 mmHg [p < .001], respectively), while HR increased (greatest net effect: +9 ± 6 beats per minute; p < .001). CONCLUSION: A single bout of arm crank exercise promotes pleasurable feelings while reducing blood pressure in patients with symptomatic PAD.

Walking Capacity Is Positively Related with Heart Rate Variability in Symptomatic Peripheral Artery Disease.

OBJECTIVES: The aim was to investigate the association between walking capacity and HRV in patients with symptomatic peripheral artery disease (PAD). METHODS: This was a cross sectional study. Ninety-five patients were recruited. Patients undertook a supine position for 20 minutes, with the final 10 minutes used to examine for resting HRV. Time domain, frequency domain, and non-linear indices were evaluated. A maximal treadmill test (Gardner protocol) was performed to assess maximal walking distance (MWD) and claudication distance (CD) in groups of PAD patients based upon their walking abilities (low, moderate, high). Differences between PAD patient groups were examined using non-parametric analyses, and Spearman rank correlations identified the relationship between MWD and CD, and HRV parameters. RESULTS: Symptomatic PAD patients with high MWD exhibited significantly greater HRV than patients with low MWD. Furthermore, MWD was positively associated with time domain and non-linear indices of HRV (all p < .05). However, no statistically significant correlations were observed between CD and HRV parameters or between PAD groups. CONCLUSION: A greater walking capacity is associated with better HRV in symptomatic PAD patients.

Reliability of heart rate measures during walking before and after running maximal efforts.

Previous studies on HR recovery (HRR) measures have utilized the supine and the seated postures. However, the most common recovery mode in sport and clinical settings after running exercise is active walking. The aim of the current study was to examine the reliability of HR measures during walking (4 km · h(-1)) before and following a maximal test. Twelve endurance athletes performed an incremental running test on 2 days separated by 48 h. Absolute (coefficient of variation, CV, %) and relative [Intraclass correlation coefficient, (ICC)] reliability of time domain and non-linear measures of HR variability (HRV) from 3 min recordings, and HRR parameters over 5 min were assessed. Moderate to very high reliability was identified for most HRV indices with short-term components of time domain and non-linear HRV measures demonstrating the greatest reliability before (CV: 12-22%; ICC: 0.73-0.92) and after exercise (CV: 14-32%; ICC: 0.78-0.91). Most HRR indices and parameters of HRR kinetics demonstrated high to very high reliability with HR values at a given point and the asymptotic value of HR being the most reliable (CV: 2.5-10.6%; ICC: 0.81-0.97). These findings demonstrate these measures as reliable tools for the assessment of autonomic control of HR during walking before and after maximal efforts.

Effect of a training week on heart rate variability in elite youth rugby league players.

The aim of this study was to examine the influence of weekly training including a competitive game on heart rate (HR) variability (HRV). Youth players (n=9, age 17-20 years) were monitored during daily supine rest (10 min) and standing (8 min), 5 times over 8 days. Heart rate recordings were analysed for time domain, frequency (e. g. low frequency [LF], high frequency [HF]) domain and non-linear measures of HRV and compared using ANOVA or Friedman's tests. Relationships between HRV and training workloads were examined via Spearman rank rho (ρ) correlation coefficients. Prior to a game, mean HR was significantly increased and remained elevated until 2 days post-game while parasympathetic modulations (HF) were significantly reduced (p<0.05). The supine to standing change in HRV was significantly reduced for up to 4 days post-game (LF/HF ratio, - 1.0±2.9 vs. - 3.0±1.9, p<0.05). These results confirm that prior to a game, players exhibited reduced parasympathetic and/or predominant sympathetic modulation with the game significantly reducing autonomic responses to standing for up to the following 4 days. Identification of day to day fluctuations in HRV may provide a helpful tool for monitoring player workload to maximise training and game performance.

Seasonal changes in physical performance and heart rate variability in high level futsal players.

The aim of this study was to determine the changes in physical performance and resting heart rate variability (HRV) in professional futsal players during the pre-season and in-season training periods. 11 athletes took part in the study (age=24.3±2.9 years; height=176.3±5.2 cm; weight=76.1±6.3 kg), and performed a repeated-sprint ability (RSA) test [6×40 m (20+20 m with a 180° change of direction) sprints separated by 20 s of passive recovery] and Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1) at 3 different moments (M1=beginning of pre-season; M2=end of pre-season; M3=mid in-season). The HRV indices were assessed at the same moments. After the short pre-season (3-week), mean RSA time (RSAmean) (M1=7.43±0.2 s; M2=7.24±0.2 s; P=0.003), decrement in RSA performance (RSAdecrement) (M1=6.7±0.3%; M2=5.0±0.9%; P=0.001), and Yo-Yo IR1 distance (M1=1.244±298 m; M2=1.491±396 m; P=0.002) were significantly improved (P<0.05). During the in-season (i. e., M3), performance in Yo-Yo IR1 and RSAmean were maintained. In contrast, RSAbest (M2=6.89±0.2 to M3=6.69±0.3; P=0.001) was improved and RSAdecrement (M2=5.0±0.9% to M3=6.6±0.9%; P=0.001) was impaired. At M2, there was an increase in HRV vagal-related indices compared with M1 that was maintained at M3. In conclusion, after a short pre-season, futsal players improved their RSA and Yo-Yo IR1 performance with concomitant improvements in HRV. These indices were maintained during the in-season period while RSAbest was improved and RSAdecrement impaired. Frequent monitoring of these performances and HRV indices may assist with identification of individual training adaptations and/or early signs of maladaption.

Influence of cycle ergometer type and sex on assessment of 30-second anaerobic capacity and power.

This study examined the influence of cycle ergometer type and sex on assessment of 30-s anaerobic capacity and power. 41 healthy adults performed a 30-s anaerobic cycle test using a mechanically- (ME) and air-braked (AE) ergometer in a randomised order, approximately 7 days apart. Peak heart rate (HR) and rating of perceived exertion were similar between tests with peak HR greater for females compared to males (187.0 ± 9.1 vs. 180.8 ± 9.9 bpm, p<0.05). Peak power (1 100 ± 330 vs. 802 ± 225 W), mean power (793 ± 223 vs. 587 ± 156 W) and total work (23.8 ± 6.7 vs. 17.6 ± 4.7 kJ) were greater for AE compared to ME (p<0.001) and greater for males compared to females (p<0.001). The mean difference for anaerobic capacity and power between AE and ME were similar for males and females (37-41% vs. 33-35%, p>0.05). Peak lactate was greater for AE compared to ME (16.1 ± 3.4 vs. 14.8 ± 2.9 mmol·L (-1); p<0.05) and greater for males compared to females (16.2 ± 3.5 vs. 14.6 ± 2.7 mmol·L (-1); p<0.05). The current study demonstrated that anaerobic power and capacity were substantially greater when assessed using AE compared to the traditional ME with the difference between ergometer types unaffected by sex. Ergometer type should be considered when comparing anaerobic results across populations and/or studies.

The effects of including quality of life responses in models to predict walking performance of patients with intermittent claudication.

OBJECTIVES: To examine the accuracy of previously developed prediction models of treadmill walking performance in patients with intermittent claudication (IC) due to peripheral arterial disease (PAD); and to examine the accuracy of new prediction models. DESIGN: Analysis of data collected in a previous randomised clinical trial. MATERIALS: Ninety-three assessments of 28 patients diagnosed with IC due to PAD. METHODS: Patients undertook routine clinical assessments, quality of life (QOL) questionnaires and treadmill walking tests. Walking performance and estimates based on prediction models were compared via paired t-tests or Wilcoxon Rank Sum tests. Stepwise linear regression generated models to predict walking performance from clinical measures and QOL responses. Accuracy was determined as the absolute error between model estimates and patient results. RESULTS: Walking performance was significantly underestimated (35-71% error) by previously developed prediction models. Models developed in the current study identified QOL responses as the most significant predictors of current walking performance but these models still resulted in substantial errors (19-84%). CONCLUSIONS: Previously published predictors of walking performance significantly underestimated patient's ability in practise. Predictions based upon clinical measurements and QOL responses were developed however, their accuracy was also limited. Further research is needed regarding walking performance prediction to assist clinicians with assessment of PAD severity and treatment effectiveness.

Impact of fire-fighters training on a female with smoldering multiple myeloma.

The purpose of this study was to examine the influence of a fire-fighting training regime on the cardiac autonomic control of a middle-aged female diagnosed with smoldering multiple myeloma (SMM). Cardiac autonomic control was monitored by heart rate variability (HRV) analysis in the patient during the last six-week period of a one and half year training period. Compared with healthy, physically active age-matched females, the patient demonstrated similar HRV parameters. Furthermore, the patient experienced a positive evolution of the SMM during this training period. These findings indicate: 1) the beneficial effects of high intensity physical training on cardiac autonomic function in a SMM patient; 2) the potential value of HRV monitoring in cancer patients undertaking regular physical activity.

The reliability of VO2(peak) determination in healthy females during an incremental arm ergometry test.

This study examined the reliability of an incremental arm ergometry (AE) protocol during peak aerobic power (VO2(peak)) determination in healthy females. Fifteen females completed two incremental AE tests to exhaustion, seven to eleven days apart, using a mechanically braked arm ergometer. The initial work rate was 16W and increased by 16W every two minutes until exhaustion. Significant differences between tests were determined by repeated measures ANOVA, and paired t-tests or Wilcoxon signed-rank tests, where appropriate. Reliability was determined by intraclass correlation coefficients (ICC), typical error, coefficient of variation (CV) and measurement bias/ratio and 95% limits of agreement (LOA). Peak cardio-respiratory responses were similar between tests, except for tidal volume (1.95 +/-0.47 vs. 1.81 +/- 0.41 L, P<0.05). Reliability for peak variables was moderate to high (ICC=0.659-0.941; CV< or =10%) while LOA were considerable for most variables including VO2(peak) (LOA=0.57 L.min(-1)). Similar peak cardio-respiratory responses, low CV and moderate-high ICC confirmed the reliability of the current incremental AE protocol to be similar to that of prior reported protocols for VO2(peak) determination. Substantial within-participant variability (LOA) for respiratory rate and tidal volume was common during the AE protocol and possibly reflects the influence of respiratory entrainment on reliability that requires further investigation.

Moderate-term reproducibility of heart rate variability during rest and light to moderate exercise in children.

Previous studies have demonstrated the high reproducibility of heart rate variability (HRV) measures in adults while little information exists concerning HRV reproducibility in children. Subsequently, the aim of the current study was to examine the moderate-term reproducibility of heart rate and frequency domain measures of HRV during rest and light to moderate exercise in children. Ten healthy children (6 males, 4 females) aged between 7 and 12 years of age volunteered for this study with HRV recordings obtained during supine rest and three treadmill walking exercise work rates (< or =60% maximum heart rate), initially and then 8 weeks later. Differences (P < 0.05) between variables were examined using paired t-tests or Wilcoxon signed rank tests while reliability and reproducibility were examined by intraclass correlation coefficients (ICC), coefficients of variation (CV), and mean bias ratio and ratio limits of agreement (LOA). Heart rate and all measures of HRV at rest and exercise were unchanged after 8 weeks. Significant ICC were documented primarily during rest (0.72-0.85) while weaker relationships (-0.02-0.87) were evident during exercise. A large range of CV was identified during rest (6-33%) and exercise (3-128%) while the ratio LOA were variable and substantial (1.04-2.73). Despite similar HRV over an 8-week period, variable ICC and sizable CV and ratio LOA indicate moderate to poor reproducibility of HRV in children, particularly during light to moderate exercise. Studies examining HRV in children should include age- or maturation stage-matched control participants to address the age-related change in HRV and inadequate HRV reliability.

Moderate-term reproducibility of heart rate variability during rest and light to moderate exercise in children

Previous studies have demonstrated the high reproducibility of heart rate variability (HRV) measures in adults while little information exists concerning HRV reproducibility in children. Subsequently, the aim of the current study was to examine the moderate-term reproducibility of heart rate and frequency domain measures of HRV during rest and light to moderate exercise in children. Ten healthy children (6 males, 4 females) aged between 7 and 12 years of age volunteered for this study with HRV recordings obtained during supine rest and three treadmill walking exercise work rates (¡Ü60 percent maximum heart rate), initially and then 8 weeks later. Differences (P < 0.05) between variables were examined using paired t-tests or Wilcoxon signed rank tests while reliability and reproducibility were examined by intraclass correlation coefficients (ICC), coefficients of variation (CV), and mean bias ratio and ratio limits of agreement (LOA). Heart rate and all measures of HRV at rest and exercise were unchanged after 8 weeks. Significant ICC were documented primarily during rest (0.72-0.85) while weaker relationships (-0.02-0.87) were evident during exercise. A large range of CV was identified during rest (6-33 percent) and exercise (3-128 percent) while the ratio LOA were variable and substantial (1.04-2.73). Despite similar HRV over an 8-week period, variable ICC and sizable CV and ratio LOA indicate moderate to poor reproducibility of HRV in children, particularly during light to moderate exercise. Studies examining HRV in children should include age- or maturation stage-matched control participants to address the age-related change in HRV and inadequate HRV reliability.

Determinants of endothelial function in a cohort of patients with peripheral artery disease.

OBJECTIVES: Endothelial dysfunction assessed by brachial artery flow-mediated dilatation (FMD) has been associated with cardiovascular events. There have been relatively few studies examining FMD or other measures of endothelial function in patients with peripheral artery disease (PAD). The aim of this study was to examine determinants of FMD in a homogenous cohort of patients with PAD. METHODS: We prospectively assessed patients presenting with life style-limiting intermittent claudication to establish the presence of cardiovascular risk factors, obesity and metabolic syndrome. Fasting serum was assayed for lipids, C-reactive protein, adiponectin, leptin, resistin and osteoprotegerin (OPG). FMD was measured by high-resolution ultrasound. RESULTS: Serum concentrations of OPG were elevated in patients with obesity and metabolic syndrome. FMD was impaired in patients with obesity and metabolic syndrome and negatively correlated with serum concentrations of OPG. By multiple regression analysis, metabolic syndrome was independently associated with impaired FMD after adjustment for age, smoking, ischaemic heart disease, cerebrovascular disease and severity of PAD. CONCLUSIONS: Our findings suggest that metabolic syndrome is an important determinant of endothelial function in patients with PAD, and OPG may be a useful biomarker of this effect.

Predictors of 1000-m outrigger canoeing performance.

UNLABELLED: This study examined the relationships between body composition, peak oxygen consumption and 1000-m time trial performance of female outrigger canoeists. PROCEDURES: Female outrigger canoeists (n = 17) completed anthropometric profiling and a 1000-m outrigger ergometer time trial, during which expired air was measured continuously and analysed at 15-s intervals for determination of peak oxygen consumption. Heart rate, stroke rate and power output were also recorded at 15-s intervals. Blood lactate was measured immediately and at 3-, 5- and 7-min post-exercise. Mean power output, peak power output and progressive split times were highly correlated (r > 0.80) to 1000-m performance. Arm girths, humerus breadth, mesomorphy, peak oxygen consumption, ventilation, mean heart rate and peak lactate were moderately correlated (r > 0.50) to 1000-m performance. Stepwise multiple regression analysis verified that mean power output and to a lesser extent flexed arm girth, humerus breadth, waist girth and sitting height can predict 1000-m performance. Enhanced 1000-m performance of female outrigger canoeists appears to be achieved through a combination of greater power production and maintenance, a muscular stature and to a lesser extent, a higher aerobic capacity. These characteristics should be considered when selecting crews.

Aerobic power and anthropometric characteristics of elite basketball referees.

AIM: The current study aimed to document the aerobic power and body composition of elite basketball referees. METHODS: Prior to the 2000/2001 Men's National Basketball League season, 25 male elite referees completed the Multistage Shuttle run test followed by body composition (body fat%) determination via bioelectrical impedance (BI) (Adult and Athlete modes) and a restricted anthropometric profile. Significant correlations between BI and anthropometric measures were examined via Pearson product correlation coefficients. RESULTS: Referees demonstrated a mean (SD) aerobic power of 50.8 (3.2) mL . kg-1 . min(-1) and body fat% of 23.8% (8.4%). Body fat% was similar for BI (Adult) and several anthropometric equations. Significant correlations were obtained between BI (Adult) and body fat%, and BI (Adult) and sum of skinfolds. Similar correlations were obtained for BI (Athlete) mode despite a significantly lower body fat%. Regression equations for the prediction of body fat% and sum of skinfolds from BI (Adult) were determined. CONCLUSIONS: Elite basketball referees demonstrated significantly greater aerobic power and similar body composition to the general community. In the euhydrated state, BI (Adult) provided a valid measurement of body fat% in elite basketball referees.

Cardiovascular stress on an elite basketball referee during national competition.

This case report examined the cardiovascular stress imposed on an experienced elite basketball referee during national competition. The average heart rate was similar for all matches, approximated 73% of maximum heart rate, and was experienced for most (>63%) of the match. Similar relative exercise intensity was demonstrated regardless of match play (men's v women's) and officiating type (two v three-referee). Further study is needed to document the physiological characteristics of elite basketball referees for greater performance.