Search

Objectives: To examine potential changes in mental and physical fatigue across an elite netball pre-season training phase and relationships between mental fatigue, physical fatigue, salivary cortisol (sCort) and alpha-amylase (sAA).Design: Observational with repeated measures.Methods: Across a 16-week pre-season, 10 elite female netballers (25.3 ± 3.7y) rated their physical fatigue, mental fatigue and readiness to perform on 100-mm visual analogue scales, and provided salivary samples for sCort and sAA analyses.Results: Linear mixed model analyses revealed elevated (p < 0.05) ratings of mental fatigue for weeks 12, 14 and 15 v 1; 12, 14 and 15 v 4 and 14 v 7. Higher (p < 0.05) ratings of physical fatigue were reported on weeks 6, 10, 11 and 12-16 compared to week 4; and 10 and 13 compared to week 7. Moderate and large ES differences were found between multiple weeks. Mental and physical fatigue demonstrated a shared variance of 14.3% (r = 0.38, p < 0.001) and an inverse relationship was observed between mental fatigue and readiness to perform (r = -0.50; p < 0.001). Changes in sCort nor sAA were not related to changes in mental or physical fatigue.Conclusions: Mental fatigue fluctuated across the 16-week pre-season phase with elevated ratings observed in the later weeks. Whilst value remains in identifying subjective tools to assess mental fatigue; salivary biomarkers do not appear to be a suitable objective indicator of mental fatigue in the applied sporting environment. Practitioners should work to identify and manage mental fatigue with the same level of importance given to the periodisation of physical fatigue. [ABSTRACT FROM AUTHOR]

Cancer-related fatigue (CRF) is a prevalent and persistent symptom from androgen deprivation therapy (ADT) in prostate cancer. The Mediterranean-style dietary pattern (MED-diet) offers a plausible mechanism to mitigate CRF through reducing inflammation and improving body composition. This study aimed to evaluate the effects of a 12-week MED-diet, compared to usual care, on CRF and quality of life in men with prostate cancer treated with ADT. Twenty-three men (65.9 ± 7.8 years; body mass index: 29.6 ± 2.7 kg/m2; ADT duration: 33.8 ± 35.6 months) receiving ADT for ≥3 months were randomly assigned (1:1) to 12-weeks of usual care or the MED-diet involving six individualised nutrition consults. Primary outcomes included CRF [Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue scale (FACIT-F) and quality of life [FACIT-General (FACIT-G)], secondary outcomes included body mass/composition and interleukin (IL)-6 and IL-8 concentrations measured at baseline, 8-weeks and 12 weeks. Intervention feasibility was measured by intervention safety, study completion rate, consult attendance, and adherence to the MED-diet through the Mediterranean-diet adherence screener (MEDAS). Intention to treat linear mixed models were used to determine changes in outcomes between the MED-diet and usual care at baseline, 8-weeks and 12-weeks. The MED-diet improved CRF (FACIT-F) at 8-weeks [+4.8 (0.0, 9.8); P = 0.05] and 12-weeks [+7.2 (2.2, 12.0); P = 0.005], quality of life (FACIT-G) at 12-weeks [+9.2 (2.7, 15.8); P = 0.006], reduced total body mass at 8-weeks [−2.51 kg (−4.25, −0.78); P = 0.005] and 12-weeks [-2.97 kg (−4.71, −1.25); P = 0.001], lean mass at 8-weeks [−1.50 kg (−2.91, −0.10); P = 0.036], and IL-8 at 8-weeks [-0.18 ng/ml (−0.34, −0.02); P = 0.029] compared to usual care. The MED-diet demonstrated zero adverse events, 91% study completion, 100% attendance, and 81% adherence to the MEDAS. The MED-diet is safe and feasible, and has the potential to improve CRF and quality of life in overweight men treated with ADT compared to usual care. Further exploration of the MED-diet is warranted in a larger powered sample size to consolidate these findings. [ABSTRACT FROM AUTHOR]

Objectives: Recent research has revealed that low volume resistance 'priming' exercise may improve neuromuscular performance when completed within 48h before competition. The aim of this study was to investigate the current prevalence and application of this strategy by practitioners in sport.Design: This study surveyed practitioners who were currently programming and/or prescribing resistance training programs for high performance athletes.Methods: Sixty-nine practitioners completed the online survey relating to their perceptions of resistance priming exercise strategies and the training methods prescribed in the days prior to competition.Results: Fifty-one percent of respondents currently prescribed priming exercise. Of the practitioners who prescribed this strategy, most respondents (59%) prescribed this session within 8h of competition. Sessions typically included 2-3 upper body and lower body exercises (mean=2.5±0.7 and 2.1±0.6 respectively), usually involving both loaded and unloaded activities. Large variations in exercise selection were reported, however, unloaded jumps (87%), loaded jumps (60%) and bench press (56%) were commonly prescribed. A low volume of sets (mean=2.8±0.9) and repetitions (mean=3.8±1.3) were used during these sessions. Lastly, various resistance loading strategies were prescribed, ranging from unloaded activities to heavy loaded exercises performed at ≥85% 1RM.Conclusions: Priming exercise is currently prescribed by many practitioners to prepare athletes for competition. A wide range of priming exercise methods are used, despite limited evidence supporting these methods. Future research should examine the effects of the various priming methods which are currently applied in practice. [ABSTRACT FROM AUTHOR]

Objectives: Fluctuating endogenous and exogenous ovarian hormones may influence exercise parameters; yet control and verification of ovarian hormone status is rarely reported and limits current exercise science and sports medicine research. The purpose of this study was to determine the effectiveness of an individualised three-step method in identifying the mid-luteal or high hormone phase in endogenous and exogenous hormone cycles in recreationally-active women and determine hormone and demographic characteristics associated with unsuccessful classification.Design: Cross-sectional study design.Methods: Fifty-four recreationally-active women who were either long-term oral contraceptive users (n=28) or experiencing regular natural menstrual cycles (n=26) completed step-wise menstrual mapping, urinary ovulation prediction testing and venous blood sampling for serum/plasma hormone analysis on two days, 6-12days after positive ovulation prediction to verify ovarian hormone concentrations.Results: Mid-luteal phase was successfully verified in 100% of oral contraceptive users, and 70% of naturally-menstruating women. Thirty percent of participants were classified as luteal phase deficient; when excluded, the success of the method was 89%. Lower age, body fat and longer menstrual cycles were significantly associated with luteal phase deficiency.Conclusions: A step-wise method including menstrual cycle mapping, urinary ovulation prediction and serum/plasma hormone measurement was effective at verifying ovarian hormone status. Additional consideration of age, body fat and cycle length enhanced identification of luteal phase deficiency in physically-active women. These findings enable the development of stricter exclusion criteria for female participants in research studies and minimise the influence of ovarian hormone variations within sports and exercise science and medicine research. [ABSTRACT FROM AUTHOR]

Objectives: Collision frequency during rugby league matches is associated with team success, greater and longer lasting fatigue and increased injury risk. This study researched the sensitivity and specificity of microtechnology to count collision events during rugby league matches.Design: Diagnostic accuracy study.Methods: While wearing a microtechnology device (Catapult, S5), eight professional rugby league players were subjected to a total of 380 collision events during matches. Video footage of each match was synchronised with microtechnology data. The occurrence of each collision event was coded in comparison with whether that event was or was not detected by microtechnology.Results: Microtechnology detected 371 true-positive collision events (sensitivity=97.6±1.5%). When low-intensity (<1 PlayerLoad AU), short duration (<1s) events were excluded from the analysis, specificity was 91.7±2.5%, accuracy was 92.7±1.3%, positive likelihood ratio was 11.4×/÷1.4 and the typical error of estimate was 7.8%×/÷1.9 (d=0.29×/÷1.9, small). Microtechnology collisions were strongly and positively correlated with video coded collision events (r=0.96). The ability of microtechnology to detect collision events improved as the intensity and duration of the collision increased.Conclusions: Microtechnology can identify 97.6% of collision events during rugby league match-play. The typical error associated with measuring contact events can be reduced to 7.8%, with accuracy (92.7%) and specificity (91.7%) improving, when low-intensity (<1 PlayerLoad AU) and short duration (<1s) collision reports are excluded. This provides practitioners with a measurement of contact workload during professional rugby league matches. [ABSTRACT FROM AUTHOR]

Objectives: To investigate β-alanine supplementation use and level of knowledge amongst professional footballers.Design: Cross-sectional survey of Australian professional football players.Methods: Questionnaires assessing β-alanine supplementation behaviours, level of knowledge and sources of information were completed by professional rugby union (RU) (n=87), rugby league (RL) (n=180) and Australian Rules Football (ARF) (n=303) players.Results: Approximately 61% of athletes reported β-alanine use, however use by ARF football players (44%) was lower than that of RU (80%) and RL players (80%). The majority of respondents were not using β-alanine in accordance with recommendations. Only 35% of the participants were able to correctly identify the potential benefits of β-alanine supplementation. The main information sources that influenced players' decision to use β-alanine were strength and conditioning coach (71%) and dietitian (52%). Forty-eight per cent of athletes never read labels prior to supplementing and only 11% completed their own research on β-alanine. Compared to RL and ARF players, RU players had both a greater knowledge of β-alanine supplementation and better supplementation practices.Conclusions: Despite over half the surveyed professional footballers using β-alanine, the majority of athletes used β-alanine in a manner inconsistent with recommendations. A better understanding of the environment and culture within professional football codes is required before supplement use becomes consistent with evidence based supplement recommendations. [ABSTRACT FROM AUTHOR]

As land is converted to agriculture (e.g., pastures), natural vegetation is repeatedly disturbed, creating various levels of habitat alteration in which flowering plants and pollinators (e.g., bees) interact. Community structure of flowering plants, bees, and flower-bee interactions may each respond to disturbance, but potentially in different ways or magnitudes. We studied flowering plants, bees, and their interactions across four mechanical disturbance levels in and near Archbold Biological Station, Florida (USA) for one year, using repeated sampling with standard techniques in replicated plots. Data were analyzed for community structure, flower-bee interactions and bipartite network structure. Over 7500 flowering plants (81 species) and almost 5000 bees (48 species) were sampled, representing > 80% of estimated species richness. Disturbance altered available flower diversity and both shifted and simplified compositions of floral and bee communities. Importantly, the number of foraging bee species did not decrease with disturbance but fewer bee species interacted with flowers given greater disturbance, indicating that disturbance reduced successful foraging. Interaction networks became simpler with disturbance, and the non-native European honey bee ( Apis mellifera ) became more dominant as disturbance intensity increased. Flower-bee interactions were most sensitive to disturbance. For some native bees, anthropogenic disturbance may contribute to ecological trap conditions and drive long-term diversity patterns. Attention to interaction networks will help land managers identify plant species to conserve and restore flowering plants that are vital to native pollinator communities. [ABSTRACT FROM AUTHOR]

• Humans impact terrestrial ecosystems through our actions, often permanently. • We find equations to predict a major human impact – our removal of plants. • Humans act like other predators to use more plants where more exist. • But climate, human population, economy, and technology also affect that pattern. • Strong predictions for where impacts occur helps to better manage those impacts. Human impacts on natural systems are often analysed using a statistical model based on the 50-year old IPAT concept, where impact (I) is a function of population (P), affluence (A), and technology (T). Varied results have accrued, but problems remain: ecological predictors are not part of the anthropocentric IPAT concept or statistical model; vastly different countries are often treated as statistical replicates; alternative hypotheses are rarely compared; and most studies evaluated only CO 2 emissions as impacts. Here we compare alternative mixed-effect models to predict human appropriation of net primary production (HANPP) as an indicator of global human impacts at relatively fine scale (5 arc-min grid). Predictors represent anthropocentric (P, A and T) and/or ecological (plant biomass and climate) effects, with countries (N = 168) and/or anthropogenic biomes (anthromes; N = 19) as random effects. The most efficient models predict location and amount of HANPP well (R2 = 0.91 and 0.63, respectively) and use all predictors listed above. In both cases, ecological predictors and population have greatest effects on HANPP, consistent with a general, ecological predator–prey relationship modified by socio-ecological conditions. Global human impacts on terrestrial ecosystems (measured as HANPP) depend on both ecological and socioeconomic factors revealed here. Understanding these relationships is a necessary step toward mitigating human impacts on land. [ABSTRACT FROM AUTHOR]

Objectives This study examined the influence of physical qualities on markers of fatigue and muscle damage following rugby league match-play. Design Between subjects design. Methods Twenty-one male youth rugby league players (age 19.2 ± 0.7 years; height 180.7 ± 5.6 cm; body mass 89.9 ± 10.0 kg) participated in the study. Yo-Yo intermittent recovery test (level 1), 3 repetition maximum back squat and bench press were assessed prior to 2 competitive fixtures. Neuromuscular fatigue (countermovement jump [CMJ] and plyometric push-up [PP]), and blood creatine kinase (CK) were assessed before and after match-play. During match-play, movements were recorded using microtechnology. Players were divided into high- and low-groups based on physical qualities. Results High Yo-Yo and squat performance resulted in greater loads during match-play ( p < 0.05). There were larger reductions in CMJ power in the low Yo-Yo group at both 24 (ES = −1.83), and 48 h post-match (ES = −1.33). Despite greater internal and external match loads, changes in CMJ power were similar between squat groups. There were larger increases in blood CK in the low Yo-Yo group at 24 (73% vs. 176%; ES = 1.50) and 48 h post-match (28% vs. 80%; ES = 1.22). Despite greater contact loads, the high squat group exhibited smaller changes in blood CK post-match (ES = 0.25–0.39). Conclusions Post-match fatigue is lower in players with well-developed high-intensity running ability, and lower body strength, despite these players having greater internal and external match loads. [ABSTRACT FROM AUTHOR]

Objectives Physical contact is frequent in rugby league competition and is thought to be a major contributor to the fatigue and creatine kinase (CK) response, although direct evidence is lacking. The aim of this study was to investigate the influence that physical contact had on the fatigue and CK response to small-sided games. Design Cross-over, counter-balanced study. Methods Twenty-three junior elite rugby league players were divided into two groups. Group one played a contact game on day 1 before playing a non-contact game 72 h later; group two played the games in reverse order. The rules were identical for each game, with the only difference being a 10 s contact bout every 50 s during the contact game. Upper and lower body neuromuscular fatigue and blood concentrations of CK were assessed immediately before, immediately after, and 12 and 24 h after the games. During each game, players wore global positioning system units to provide information on movements. Results CK increased after both games, peaking immediately following the non-contact game; CK was still rising 24 h following the contact game. The difference between the two conditions was practically meaningful at this point (likelihood = likely, 82%; ES = 0.86). There were moderate to large reductions in upper body power following the contact game (ES = -0.74 to -1.86), and no reductions following the non-contact game. Conclusions This study indicates that large increases in blood CK and upper body fatigue result from physical contact. Training sessions involving physical contact should be performed well in advance of scheduled games. [ABSTRACT FROM AUTHOR]

Objectives To determine whether differences in training status, body composition and/or habitual caffeine intake influenced serum caffeine concentrations following caffeine ingestion. Design Single-blind. Methods Trained cyclists/triathletes (n = 14) and active (n = 14) males consumed 6 mg kg-1 anhydrous caffeine. Peak, total and time to peak serum caffeine concentrations were determined from venous blood samples at baseline and 6 time-points over 4 h following intake. Body composition was assessed by dual energy X-ray absorptiometry and habitual caffeine intake by a questionnaire. Results Trained cyclists/triathletes had 16% lower peak caffeine concentrations following caffeine ingestion compared to active individuals, although this was not statistically significant (p = 0.066). There was no significant difference between trained cyclists/triathletes and active males in total (p = 0.131) or time to peak (p = 0.249) serum caffeine concentrations. Fat mass was significantly associated with total (r = 0.427, p = 0.038) but not peak (r = 0.343, p = 0.101) or time to peak serum caffeine concentration (β = 0.00008, p = 0.961). There were no associations between habitual caffeine intake and peak, total or time to peak serum caffeine concentrations. Conclusions Following caffeine ingestion three findings from the study were evident: (1) endurance-trained athletes trended towards lower peak caffeine concentrations compared to active males; (2) higher fat mass was associated with higher concentrations of caffeine in the blood over 4 h, and (3) habitual caffeine intake does not appear to influence serum caffeine concentrations. Identification of the optimal conditions to ensure peak availability of caffeine within the blood and/or overcoming some of the variation in how individuals respond to caffeine requires consideration of the training status and body composition of the athlete. [ABSTRACT FROM AUTHOR]

Objectives The purpose of the present study was to examine a possible dose-response between pre-exercise pseudoephedrine intake and cycling time trial performance. Design Randomised, double-blind, crossover trial. Methods Ten trained male endurance cyclists (26.5 ± 6.2 years, 75.1 ± 5.9 kg, 70.6 ± 6.8 mL kg-1 min-1) undertook three cycling time trials in which a fixed amount of work (7 kJ kg-1 body mass) was completed in the shortest possible time. Sixty minutes before the start of exercise, subjects orally ingested either 2.3 mg kg-1 or 2.8 mg kg-1 body mass of pseudoephedrine or a placebo in a randomised and double-blind manner. Venous blood was sampled at baseline, pre- and post-warm up and post-exercise for the analysis of pH and lactate and glucose concentrations; plasma catecholamine and pseudoephedrine concentrations were measured at all times except post-warm up. Results Cycling time trial performance (~30 min) was not enhanced by pseudoephedrine ingestion. Plasma pseudoephedrine concentration increased from pre-warm up to post-exercise in both treatment conditions, with the 2.8 mg kg-1 body mass dose producing the highest concentration at both time points (2.8 mg kg-1 > 2.3 mg kg-1 > placebo; p < 0.001). Conclusions There was large individual variation in plasma pseudoephedrine concentration between subjects following pseudoephedrine administration. A number of factors clearly influence the uptake and appearance of pseudoephedrine in the blood and these are not yet fully understood. Combined with subsequent differences in plasma pseudoephedrine between individuals, this may partially explain the present findings and also the inconsistencies in performance following pseudoephedrine administration in previous studies. [ABSTRACT FROM AUTHOR]

Physical activity (PA) is related to colorectal cancer (CRC) mortality, with approximately 15% of CRC deaths worldwide attributable to physical inactivity. Moreover, higher levels of PA in CRC survivors have been associated with a reduced risk of the disease recurring. Despite the recognised nexus between PA and the risk of CRC, the physiological mechanisms underlying the inverse relationship between PA and mortality following CRC diagnosis are less apparent, with evidence primarily drawn from epidemiological studies. The insulin-like growth factor (IGF) axis plays a central role in cellular growth, proliferation regulation, differentiation and apoptosis. Specifically, high levels of insulin-like growth factor 1 (IGF-1) have been consistently linked to the severity of CRC tumours. Further, insulin-like growth factor binding protein 3 (IGFBP-3) regulates the bioavailability of IGF-I and therefore plays a central role in CRC prognosis. Decreasing levels of IGF-1 and increasing levels of IGFBP-3 may thus be a plausible mechanism underlying the inverse association between PA and CRC survival. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to assess the physiological responses to an intensified rugby league competition and explore the relationships between fatigue and match performance. Design: Prospective cohort study. Methods: Fifteen junior rugby league players (n =8 forwards, 7 backs; mean±SE, age 16.6±0.2 years; body mass 81.6±3.0kg; and height 178.9±1.8cm) competed in five 40min games over 5 days (two games each on days 1 and 2, one game on day 4, and no games on days 3 and 5). Over the competition, players performed a countermovement jump to assess neuromuscular fatigue, provided a fingertip blood sample to measure blood creatine kinase, and completed a questionnaire to monitor perceived wellbeing; ratings of perceived effort were recorded following each game. Global positioning system and video analysis of each game were used to assess match performance. Results: Over the first 3 days, there were progressive and large increases in neuromuscular fatigue which peaked 12h after game 4 (forwards ES=4.45, p =0.014; backs ES=3.62, p =0.029), and muscle damage which peaked 1h post game 4 (forwards ES=4.45, p =0.004; backs ES=3.94 p =0.012), as well as reductions in perceived wellbeing. These measures gradually recovered over the final 2 days of the competition. Compared to the backs, the forwards experienced greater increases in creatine kinase following game 2 (ES=1.30) and game 4 (ES=1.24) and reductions in perceived wellbeing (ES=0.25–0.46). Match intensity, high-speed running, and repeated-high intensity effort bouts decreased in games 4 and 5 of the competition. Small to large associations were observed between the changes in fatigue, muscle damage and match performance, with significant correlations between creatine kinase and repeated high-intensity effort bout number (r =−0.70, p =0.031) and frequency (r =0.74, p =0.002) and low-speed activity (r =−0.56, p =0.029). Conclusions: Fatigue and muscle damage accumulate over an intensified competition, which is likely to contribute to reductions in high-intensity activities and work rates during competition. [ABSTRACT FROM AUTHOR]

Objectives: To examine the effect of a high carbohydrate meal on serum caffeine concentration following caffeine intake. Design: Randomised, double-blind, crossover. Methods: Fourteen healthy males randomly completed 4 trials, each separated by 5 days. Participants either remained fasted (on 2 occasions) or ingested a high carbohydrate meal (2.0gkg−1 carbohydrate, 42.4±0.6kJkg−1) prior to consuming either 6 or 9mgkg−1 anhydrous caffeine. Venous blood was sampled for the analysis of serum caffeine at baseline and at 6 time-points over 4h following caffeine intake. Results: Peak caffeine concentration occurred 60min following ingestion for both the 6 and 9mgkg−1 fasted (p <0.001) trials compared to 120 and 180min following ingestion for the 6 and 9mgkg−1 fed trials, respectively (p <0.001). Peak concentration was greater in the 9mgkg−1 fasted trial than the corresponding fed condition (70±9μmolL−1 and 56±6μmolL−1, respectively) and both were greater than the 6mgkg−1 conditions (44±8μmolL−1 and 38±8μmolL−1 for 6mgkg−1 fasted and fed, respectively). Area under the caffeine curve was significantly greater (p <0.001) in the 9mgkg−1 fasted trial (3262μmolL−1 h−1), whilst areas were lowest in the 6mgkg−1 fed trial (1644μmolL−1 h−1). Conclusions: A high carbohydrate meal consumed prior to caffeine ingestion significantly reduced serum caffeine concentrations and delayed time to peak concentration. Differences in research findings between caffeine supplementation studies may, at least in part, be related to variations in postprandial timing of caffeine intake. The influence of postprandial timing should be considered when athletes consume caffeine with the aim of enhancing performance. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: To investigate whether coinciding peak serum caffeine concentration with the onset of exercise enhances subsequent endurance performance. Design: Randomised, double-blind, crossover. Methods: In this randomised, placebo-controlled, double-blind crossover study, 14 male trained cyclists and triathletes (age 31±5year, body mass 75.4±5.7kg, VO2max 69.5±6.1mLkg−1 min−1 and peak power output 417±35W, mean±SD) consumed 6mgkg−1 caffeine or a placebo either 1h (C 1h) prior to completing a 40km time trial or when the start of exercise coincided with individual peak serum caffeine concentrations (C peak). C peak was determined from a separate ‘caffeine profiling’ session that involved monitoring caffeine concentrations in the blood every 30min over a 4h period. Results: Following caffeine ingestion, peak serum caffeine occurred 120min in 12 participants and 150min in 2 participants. Time to complete the 40km time trial was significantly faster (2.0%; p =0.002) in C 1h compared to placebo. No statistically significant improvement in performance was noted in the C peak trial versus placebo (1.1%; p =0.240). Whilst no differences in metabolic markers were found between C peak and placebo conditions, plasma concentrations of glucose (p =0.005), norepinephrine and epinephrine (p ≤0.002) were higher in the C 1h trial 6min post-exercise versus placebo. Conclusions: In contrast to coinciding peak serum caffeine concentration with exercise onset, caffeine consumed 60min prior to exercise resulted in significant improvements in 40km time trial performance. The ergogenic effect of caffeine was not found to be related to peak caffeine concentration in the blood at the onset of endurance exercise. [Copyright &y& Elsevier]

Abstract: Objectives: To investigate the physical demands of professional rugby league match-play using microtechnology, and to compare these demands with typical training activities used to prepare players for competition. Design: Prospective cohort study. Methods: Thirty elite rugby league players participated in this study. Seven hundred and eighty-six. training data sets and 104 data sets from National Rugby League matches were collected over one playing season. Movement was recorded using a commercially available microtechnology unit (minimaxX, Catapult Innovations), which provided information on speeds, distances, accelerations, physical collisions and repeated high-intensity efforts. Results: Mean distances covered during match-play by the hit-up forwards, wide-running forwards, adjustables, and outside backs were 3,569m, 5,561m, 6,411m, and 6,819m, respectively. Hit-up forwards and wide-running forwards were engaged in a greater number of moderate and heavy collisions than the adjustables and outside backs, and more repeated high-intensity effort bouts per minute of play (1 bout every 4.8–6.3min). The physical demands of traditional conditioning, repeated high-intensity effort exercise, and skill training activities were all lower than the physical demands of competition. Conclusions: These results demonstrate that absolute distances covered during professional rugby league matches are greater for outside backs, while the collision and repeated high-intensity effort demands are higher for hit-up forwards and wide-running forwards. The specific physical demands of competitive play, especially those demands associated with collisions and repeated high-intensity efforts, were not well matched by those observed in traditional conditioning, repeated high-intensity effort exercise, and skills training activities. Further research is required to investigate whether modifications need to be made to these training activities to better prepare players for the demands of National Rugby League competition. [Copyright &y& Elsevier]

Abstract: Objective: To document the frequency of physical collisions and incidence of contact injury in professional rugby league match-play. Design: Prospective cohort study. Methods: Video recordings of 77 National Rugby League (NRL) matches were coded for the number and type of physical collisions in which players were involved. Each match was analysed and coded for defensive (i.e. tackles, missed tackles, and ineffective tackles) and attacking collisions (i.e. tackled in possession, broken tackles, offloads, support runs, and decoy runs). Injuries that occurred as a result of a physical collision were also recorded. Results: The total number of physical collisions performed per game was greatest in the wide running forwards (47 [95% CI, 42–52]), and was significantly greater (P <0.05) than the hit-up forwards (36 [95% CI, 32–40]), adjustables (29 [95% CI, 26–32]), and outside backs (24 [95% CI, 22–27]) positional groups. A total of 48 collision injuries were sustained, resulting in an overall injury incidence of 10.6 (95% CI, 7.6–13.6) per 10,000 collisions. Injuries resulting from attacking collisions were consistently higher than injuries sustained in defensive collisions. Wide running forwards had the lowest incidence of injury, and the adjustables and outside backs had the highest incidence of injury. Conclusions: These results highlight the physical demands associated with collisions and tackles in professional rugby league. Furthermore, the results of this study suggest that playing position and the type of collision sustained have a greater influence over contact injury risk in rugby league than the number of physical collisions performed. [Copyright &y& Elsevier]

Abstract: Objectives: To investigate the relationship between training load and injury in professional rugby league players; Design: Prospective cohort study; Methods: Seventy-nine professional rugby league players (mean±SD age, 23.3±3.8 years) participated in this four-year study. A periodized field, strength, and power training program was implemented, with training loads progressively increased in the general preparatory phase of the season and reduced during the competitive phase of the season. Training loads and injuries were recorded for each training session. Results: Training load was significantly related (P <0.05) to overall injury (r =0.82), non-contact field injury (r =0.82), and contact field injury (r =0.80) rates. Significant relationships were also observed between the field training load and overall field injury (r =0.68), non-contact field injury (r =0.65), and contact field injury (r =0.63) rates. Strength and power training loads were significantly related to the incidence of strength and power injuries (r =0.63). There was no significant relationship between field training loads and the incidence of strength and power injuries. However, strength and power training loads were significantly (P <0.01) associated with the incidence of contact (r =0.75) and non-contact (r =0.82) field training injuries. Conclusions: These findings suggest that the harder rugby league players train, the more injuries they will sustain, and that high strength and power training loads may contribute indirectly to field injuries. Monitoring of training loads and careful scheduling of field and gymnasium sessions to avoid residual fatigue is warranted to minimize the effect of training-related injuries on professional rugby league players. [Copyright &y& Elsevier]

Summary: Central hemodynamics such as ascending aortic blood pressure (BP), wave reflection and myocardial perfusion are clinically important in the context of cardiovascular health. Ultra-endurance athletes may be at greater risk of cardiovascular abnormalities due to chronically increased physiological stress placed on the cardiovascular system. This study was a cross-sectional investigation that compared central hemodynamics in ultra-endurance athletes and matched controls. Forty-four athletes (36 males; aged mean±S.D., 34±8 years) undergoing ultra-endurance training (16.3±3.7h/week) were compared to 44 matched recreationally active (1.2±0.9h/week) controls (36 males; aged 34±8 years). Brachial BP was measured using an oscillometric device while central hemodynamics including ascending aortic BP, wave reflection (augmentation index, AIx), ejection duration, sub-endocardial perfusion (SEVR) and timing of the reflected wave (T R) were determined by applanation tonometry and pulse wave analysis. There were no significant (P >0.05) differences between groups in AIx (athletes and controls; 6±12% versus 6±13%, respectively), T R (athletes and controls; 165±22ms versus 165±19ms, respectively), brachial (athletes and controls; 51±9mmHg versus 48±12mmHg, respectively) or central pulse pressure (33±5mmHg versus 31±7mmHg). However, athletes had significantly increased SEVR (226±42% versus 198±46%; P <0.001) despite having a longer ejection duration (348±19ms versus 339±18ms; P <0.05). Furthermore, the amount of exercise training volume was significantly related to central (r =−0.46; P =0.002), but not brachial pulse pressure (r =−0.28; P >0.05). Ultra-endurance athletes had increased sub-endocardial perfusion capacity and the quantity of exercise training was associated with central rather than peripheral hemodynamics. [Copyright &y& Elsevier]

Growing demand for food from finite agricultural lands requires the optimization of agricultural management, including the potential interactive effects of these practices on ecosystems. We experimentally examined the interactive and temporal effects of three ranching practices (pasture management intensity, livestock grazing, and prescribed fire) on soil nutrients in 40 geographically-isolated seasonal wetlands. Wetlands were embedded in a subtropical ranch, and the long-term experiment used a factorial design with wetlands as experimental units. Soils (0–15 cm) were collected three times over 9 years; at experiment start (2007), one year after prescribed burns started (2009), and seven years later (2016). Samples were analyzed for soil bulk density, organic matter (OM), total nitrogen (N), carbon (C), and phosphorous (P). A lag effect was observed in response to fire; differences were not observed in 2009, but were detected in 2016 after multiple fire cycles had occurred. Rangeland practices showed 2- and 3-way interactive effects, especially for total P and N stocks. Total P increased most in the wetlands embedded within highly managed, grazed, and burned pastures (2.31 ± 0.76 g m −2 yr −1 ), consistent with legacy effects of historical fertilizer application, cattle activity, and ash deposit due to fire. Wetlands in semi-natural and burned pastures had the lowest rates of soil N storage (5.13 ± 7.33 g m −2 yr −1 ) compared to all other treatments (24.5 ± 10.8 g m −2 yr −1 ). Total C stocks were not significantly impacted by ranching practices throughout the study. In summary, ranching practices can additively and interactively alter soil nutrient stocks after a time lag, and legacy effects of P application still impact wetlands decades later. Our study is one of few focused on ranchland wetlands and shows that wetlands in highly managed, grazed, and/or burned pastures can sequester soil P and N, playing an important role in nutrient processing for agricultural landscapes and watersheds. [ABSTRACT FROM AUTHOR]

Greater understanding of land management effects on species richness and composition is needed to manage biodiversity-related ecosystem services in agricultural ecosystems. Here we studied responses of vascular plants, macroinvertebrates, and ectothermic vertebrates to local and regional factors in two ranchland management intensities (semi-natural and highly-managed). Samples were collected in 40 separate wetlands embedded in the two management intensities. Based on community assembly theory, we expected a shift from regional to local-based factors as predictors of communities where local conditions become more limiting. We also expected highly managed ranchlands to most strongly “filter” community membership to become more homogeneous. Both predictions were supported though results sometimes differed among taxa. Wetland communities embedded in highly managed pastures were more homogeneous and significantly different from those in semi-natural pastures. Overall, regional factors related to propagule dispersal were most important in semi-natural pastures, and local factors (especially nutrients) were most important in highly managed pastures. However, some community metrics were consistently affected most by local or regional factors regardless of land use intensity. For instance, vegetation richness and vertebrate composition were consistently influenced by local factors, whereas macroinvertebrate composition was consistently influenced by regional factors. Based on our results, biodiversity conservation will be most effective if management efforts focus on improving local habitat conditions in highly managed areas, and on preserving regional heterogeneity in more natural areas. Taxon-specific conservation strategies should account for taxon-specific sensitivities to local and regional processes. [ABSTRACT FROM AUTHOR]