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Background Performance analysis in rugby union has become an integral part of the coaching process. Although performance analysis research in rugby and data collection has progressed, the utility of the insights is not well understood. The primary objective of this review is to consider the current state of performance analysis research in professional rugby union and consider the utility of common methods of analysing performance and the applicability of these methods within professional coaching practice. Methods SPORTDiscus electronic database was searched for relevant articles published between 1 January 1997 and 7 March 2019. Professional, male 15-a-side rugby union studies that included relevant data on tactical and performance evaluation, and statistical compilation of time-motion analysis were included. Studies were categorised based on the main focus and each study was reviewed by assessing a number of factors such as context, opposition analysis, competition and sample size. Results Forty-one studies met the inclusion criteria. The majority of these studies measured performance through the collection and analysis of performance indicators. The majority did not provide context relating to multiple confounding factors such as field location, match location and opposition information. Twenty-nine performance indicators differentiated between successful match outcomes; however, only eight were commonly shared across some studies. Five studies considered rugby union as a dynamical system; however, these studies were limited in analysing lower or national-level competitions. Conclusions The review highlighted the issues associated with assessing isolated measures of performance, lacking contextual information such as the opposition, match location, period within match and field location. A small number of studies have assessed rugby union performance through a dynamical systems lens, identifying successful characteristics in collective behaviour patterns in attacking phases. Performance analysis in international rugby union can be advanced by adopting these approaches in addition to methods currently adopted in other team sports.

Sleeping with low carbohydrate (CHO) availability is a dietary strategy that may enhance training adaptation. However, the impact on an athlete’s health is unclear. This study quantified the effect of a short-term “sleep-low” dietary intervention on markers of iron regulation and immune function in athletes. In a randomized, repeated-measures design, 11 elite triathletes completed two 4-day mixed cycle run training blocks. Key training sessions were structured such that a high-intensity training session was performed in the field on the afternoon of Days 1 and 3, and a low-intensity training (LIT) session was performed on the following morning in the laboratory (Days 2 and 4). The ingestion of CHO was either divided evenly across the day (HIGH) or restricted between the high-intensity training and LIT sessions, so that the LIT session was performed with low CHO availability (LOW). Venous blood and saliva samples were collected prior to and following each LIT session and analyzed for interleukin-6, hepcidin 25, and salivary immunoglobulin-A. Concentrations of interleukin-6 increased acutely after exercise (p p p = .046). There appears to be minimal impact to markers of immune function and iron regulation when acute exposure to low CHO availability is undertaken with expert nutrition and coaching input.

Purpose: The risk of exercise-induced endotoxemia is increased in the heat and is primarily attributable to changes in gut permeability resulting in the translocation of lipopolysaccharides (LPS) into the circulation. The purpose of this study was to quantify the acute changes in gut permeability and LPS translocation during submaximal continuous and high-intensity interval exercise under heat stress. Methods: A total of 12 well-trained male runners (age 37 [7] y, maximal oxygen uptake [VO2max] 61.0 [6.8] mL·min−1·kg−1) undertook 2 treadmill runs of 2 × 15-minutes at 60% and 75% VO2max and up to 8 × 1-minutes at 95% VO2max in HOT (34°C, 68% relative humidity) and COOL (18°C, 57% relative humidity) conditions. Venous blood samples were collected at the baseline, following each running intensity, and 1 hour postexercise. Blood samples were analyzed for markers of intestinal permeability (LPS, LPS binding protein, and intestinal fatty acid–binding protein). Results: The increase in LPS binding protein following each exercise intensity in the HOT condition was 4% (5.3 μg·mL−1, 2.4–8.4; mean, 95% confidence interval, P −1, 1.8–7.4; P = .002), and 30% (3.0 μg·mL−1, 0.03–5.9; P = .047) greater than in the COOL condition. LPS was 69% higher than baseline following running at 75% VO2max in the HOT condition (0.2 endotoxin units·mL−1, 0.1–0.4; P = .011). Intestinal fatty acid–binding protein increased 43% (2.1 ng·mL−1, 0.1–4.2; P = .04) 1 hour postexercise in HOT compared with the COOL condition. Conclusions: Small increases in LPS concentration during exercise in the heat and subsequent increases in intestinal fatty acid–binding protein and LPS binding protein indicate a capacity to tolerate acute, transient intestinal disturbance in well-trained endurance runners.

The final hours of preparation before competition are important for performance. Recovery, preparation and warm up protocols are evolving continuously and include passive and active modalities often developed by "trial and error" approaches. Passive modalities, such as whole-body cryotherapy (WBC), have the potential to enhance both recovery and preparation. Whole-body cryotherapy has generally been used within a recovery setting after competition or strenuous training for athletes, and in clinical settings for the general population. However, the acute hormonal, anti-inflammatory, perceptual and psychological responses yielded by a single, or repeated, bouts of WBC indicate that this practice could enhance an athlete's competition readiness when used alongside traditional elements of active warm-ups in the hours before competition in addition to aiding recovery in the hours after. Here we summarize and evaluate the acute effects of WBC exposures on physiological, performance and perceptual responses, and examine the likelihood these responses could theoretically translate into enhanced athletic performance. The potential to enhance an athlete's performance using acute passive WBC exposure is a novel intervention that requires further investigation.

Purpose: To establish levels of association between physical fitness and match activity profiles of players in the Australian Football League (AFL) participation pathway. Methods: Players (N = 287, range 10.9–19.1 y) were assessed on 20-m sprint, AFL agility, vertical jump and running vertical jump, 20-m multistage fitness test (MSFT), and Athletic Abilities Assessment. Match activity profiles were obtained from global positioning system measures: relative speed, maximal velocity, and relative high-speed running. Results: Correlational analyses revealed moderate relationships between sprint (r = .32–.57, P ≤ .05) and jump test scores (r = .34–.78, P ≤ .05) and match activity profiles in Local U12, Local U14, National U16, and National U18s, except jump tests in National U18s. AFL agility was also moderate to strongly associated in Local U12, Local U14, Local U18, and National U16s (r = .37–.87, P ≤ .05) and strongly associated with relative speed in Local U18s (r = .84, P ≤ .05). Match relative speed and high-speed running were moderate to strongly associated with 20-m MSFT in Local U14, Local U18, and National U18s (r = .41–.95, P ≤ .05) and Athletic Abilities Assessment in Local U12 and Local U18s (r = .35–.67, P ≤ .05). Match activity profile demands increased between Local U12 and National U16s, then plateaued. Conclusions: Physical fitness relates more strongly to match activity profiles in younger adolescent and national-level players. Recruiters should consider adolescent physical fitness and match activity profiles as dynamic across the AFL participation pathway.

Triathlon is characterized by the multidisciplinary nature of the sport where swimming, cycling, and running are completed sequentially in different events, such as the sprint, Olympic, long-distance, and Ironman formats. The large number of training sessions and overall volume undertaken by triathletes to improve fitness and performance can also increase the risk of injury, illness, or excessive fatigue. Short- and medium-term individualized training plans, periodization strategies, and work/rest balance are necessary to minimize interruptions to training due to injury, illness, or maladaptation. Even in the absence of health and wellbeing concerns, it is unclear whether cellular signals triggered by multiple training stimuli that drive training adaptations each day interfere with each other. Distribution of training intensity within and between different sessions is an important aspect of training. Both internal (perceived stress) and external loads (objective metrics) should be considered when monitoring training load. Incorporating strength training to complement the large body of endurance work in triathlon can help avoid overuse injuries. We explore emerging trends and strategies from the latest literature and evidence-based knowledge for improving training readiness and performance during competition in triathlon.

Objective: To identify and detail physiological factors that influence cognition in military personnel. Background: Maintenance of cognitive and task performance is important under several scenarios, none more so than in a military context. Personnel are prepared for and trained to tolerate many of the stressors they encounter; however, consideration of stressors typically extends only as far as the physical, psychological, and environmental requirements of a given task. While considering these factors certainly characterizes the broader picture, several physiological states and traits can influence cognition and thus, should also be considered. Method: A systematic review of the electronic databases Medline (PubMed), EMBASE (Scopus), PsycINFO, and Web of Science was conducted from inception up to January 2019. Eligibility criteria included current military personnel, an outcome of cognition, and the assessment of a physiological factor. Results: The search returned 60,564 records, of which 60 were included in the review. Eleven studies examined the impact of demographic factors on cognition, 16 examined fatigue, 10 investigated nutrition, and 24 the impact of biological factors on cognitive performance. Conclusion: Factors identified as having a positive impact on cognition include aerobic fitness, nutritional supplementation, and visual acuity. In contrast, factors identified as having a negative impact include fatigue arising from sustained operations, dehydration, undernutrition, and an exaggerated physiological stress response to a cognitive task or a stressor. A further subset of these factors was considered modifiable. Application: The modifiable factors identified provide avenues for training and preparation to enhance cognition in ways previously unconsidered.

Background: This study investigated the periodization of elite swimmers' training over the 25 weeks preceding the major competition of the season. Methods: We conducted a retrospective observational study of elite male (n = 60) and female (n = 67) swimmers (46 sprint, 81 middle-distance) over 20 competitive seasons (1992-2012). The following variables were monitored: training corresponding to blood lactate 4-6 mmol.L-1, >6 mmol.L-1, and maximal swimming speed; general conditioning and maximal strength training hours; total training load (TTL); and the mean normalized volumes for both in-water and dryland workouts. Latent class mixed modeling was used to identify various TTL pattern groups. The associations between pattern groups and sex, age, competition event, Olympic quadrennial year, training contents, and relative performance were quantified. Results: For the entire cohort, similar to 86-90% of the training was swum at an intensity of [La](b) 4-6 mmol.L-1, and 3.5-4.5% at > 6 mmol.L-1. Three sprint TTL patterns were identified: a pattern with two long similar to 14-15-week macrocycles, one with two similar to 12-13 week macrocycles each composed of a balanced training load, and one with a single stable flat macrocycle. The long pattern elicited the fastest performances and was most prevalent in Olympic quadrennials (i.e., 4 seasons preceding the 2004, 2008, and 2012 Olympic Games). This pattern exhibited moderate week-to-week TTL variability (6 +/- 3%), progressive training load increases between macrocycles, and more training at 6 mmol.L-1. This fastest sprint pattern showed a waveform in the second macrocycle consisting of two progressive load peaks 10-11 and 4-6 weeks before competition. The stable flat pattern was the slowest and showed low TTL variability (4 +/- 3%), training load decreases between macrocycles (P < 0.01), and more training at 4-6 mmol.L-1 (P < 0.01). Conclusion: Progressive increases in training load, macrocycles lasting about 14-15 weeks, and substantial volume of training at intensities 6 mmol.L-1, were associated with peak performance in elite swimmers. This research was partially funded by the French Institute of Sport, Expertise and Performance (INSEP) and the French Ministry in charge of sports under grant no. 14r21.

Scanlan, AT, Wen, N, Pyne, DB, Stojanovic, E, Milanovic, Z, Conte, D, Vaquera, A, and Dalbo, VJ. Power-related determinants of Modified Agility T-test performance in male adolescent basketball players. J Strength Cond Res XX(X): 000-000, 2019-Although the Modified Agility T-test (MAT) has been advocated for assessing change-of-direction performance in basketball, the power-related attributes emphasized during the test are unknown. Therefore, the aim of this study was to identify the power-related determinants of the MAT in basketball players. A cross-sectional, descriptive research design was used whereby national- and state-level male adolescent basketball players (n = 24; 17.3 ± 0.5 years) completed a battery of power-related performance tests. The tests administered included the MAT, isometric midthigh pull, 10-m sprint, countermovement jump, 1-step vertical jump, standing long jump, and repeated lateral bound. Associations between performance during the MAT and other tests were quantified, and performance in each test was compared between faster (>50th percentile) and slower (

Bunch riding in closed circuit cycling courses and some track cycling events are often typified by highly variable power output and a maximal sprint to the finish. How criterium style race demands affect final sprint performance however, is unclear. We studied the effects of 1 h variable power cycling on a subsequent maximal 30 s sprint in the laboratory. Nine well-trained male cyclists/triathletes (O2peak 4.9 ± 0.4 L⋅min-1; mean ± SD) performed two 1 h cycling trials in a randomized order with either a constant (CON) or variable (VAR) power output matched for mean power output. The VAR protocol comprised intervals of varying intensities (40-135% of maximal aerobic power) and durations (10 to 90 s). A 30 s maximal sprint was performed before and immediately after each 1 h cycling trial. When compared with CON, there was a greater reduction in peak (-5.1 ± 6.1%; mean ± 90% confidence limits) and mean (-5.9 ± 5.2%) power output during the 30 s sprint after the 1 h VAR cycle. Variable power cycling, commonly encountered during criterium and triathlon races can impair an optimal final sprint, potentially compromising race performance. Athletes, coaches, and staff should evaluate training (to improve repeat sprint-ability) and race-day strategies (minimize power variability) to optimize the final sprint.

Purpose: The extent to which hepcidin regulation after acute bouts of exercise is influenced by baseline (resting) concentrations of key iron parameters remains uncertain. This investigation explored the influence of selected iron parameters and 25-km race walk time on 3-h post-exercise hepcidin-25 levels in international-level race walkers. Methods: Twenty-four male race walkers completed a graded exercise test and a 25-km race-walk trial. Throughout the 25-km race-walk, venous blood samples were collected pre-exercise, immediately post-exercise, and at 3-h post-exercise. Blood was analysed for serum ferritin, serum iron, Interleukin-6 (IL-6), and hepcidin-25 concentration. Results: IL-6 and hepcidin-25 increased (7.6- and 7.5-fold, respectively) in response to the 25-km race-walk trial (both p < 0.01). Significant individual relationships were evident between 3-h post-exercise hepcidin-25, baseline serum ferritin and serum iron (r > 0.62; p < 0.05). Multiple regression analysis showed that these two iron parameters, in addition to post-exercise IL-6 concentration and 25-km race-walk time, accounted for ~77% of the variance in 3-h post-exercise hepcidin-25 (p < 0.01). A median split by the cohort’s baseline serum ferritin concentration (LOW: 58.0 vs. HIGH: 101.8 µg/L; p < 0.01) showed a significant between group difference in the 3-h post-exercise hepcidin-25 (LOW: 6.0 ± 3.6 vs. 11.3 ± 5.4 nM; p = 0.01), despite no differences in baseline serum iron, post-exercise IL-6, or 25-km race-walk time (all p > 0.05). Conclusion: Despite exercise activating numerous hepcidin regulators, baseline iron status appears to play a dominant role in the regulation of hepcidin-25 in elite-level athletes subsequent to endurance exercise.

Purpose:Targeted passive heating and completion of dryland-based activation exercises within the warm-up can enhance sprint freestyle performance. The authors investigated if these interventions would also elicit improvements in sprint breaststroke swimming performance.Methods:Ten national and internationally competitive swimmers (~805 FINA (Fédération internationale de natation) 2014 scoring points; 6 men, mean ± SD 20 ± 1 y; 4 women, 21 ± 3 y) completed a standardized pool warm-up (1550 m) followed by a 30-min transition phase and a 100-m breaststroke time trial. In the transition phase, swimmers wore a conventional tracksuit and remained seated (control) or wore tracksuit pants with integrated heating elements and performed a 5-min dryland-based exercise routine (combo) in a crossover design.Results:Performance in the 100-m time trial (control: 68.6 ± 4.0 s, combo: 68.4 ± 3.9 s, P = .55) and start times to 15 m (control: 7.3 ± 0.6 s; combo: 7.3 ± 0.6 s; P = .81) were not different between conditions. It was unclear (P = .36) whether combo (–0.12°C ± 0.19°C [mean ± 90% confidence limits]) elicited an improvement in core temperature maintenance in the transition phase compared with control (–0.31°C ± 0.19°C). Skin temperature immediately before commencement of the time trial was higher (by ~1°C, P = .01) within combo (30.13°C ± 0.88°C [mean ± SD]) compared with control (29.11°C ± 1.20°C). Lower-body power output was not different between conditions before the time trial.Conclusions:Targeted passive heating and completion of dryland-based activation exercises in the transition phase does not enhance sprint breaststroke performance despite eliciting elevated skin temperature immediately before time trial commencement.

To inform recruitment, selection, training and testing of male and female rugby sevens players game running movement patterns and physical characteristics were quantified across junior, senior, and elite playing levels. Anthropometric and physical testing (40 m sprint, vertical jump, Yo-Yo IR1) occurred prior to players’ national championships or international tournaments (n = 110 players), while game movements were obtained via GPS (n = 499 game files). The game movements of male players were similar across playing levels except for number of impacts >10 g which were 2 to 4-fold higher in elite (25.0 ± 11.2 impacts · game−1; mean ± SD), than junior (6.3 ± 3.5) and senior (11.8 ± 6.6) players. In men, there were fewer substantial correlations between on- and off-field measures which may reflect similar physical attributes across playing levels, and that other (strength, technical or tactical) factors may better differentiate these players. In females, elite players had more favourable on- and off-...

To verify the metabolic responses of oxygen consumption (V[Combining Dot Above]O2), heart rate (HR), blood lactate concentrations [La], and rate of perceived exertion (RPE) when swimming at an intensity corresponding to the critical velocity (CV) assessed by a 4-parameter model (CV4par), and to check the reliability when using only a single 400-m maximal front crawl bout (T400) for CV4par assessment in age-group swimmers. Ten age-group swimmers (14-16 years old) performed 50-, 100-, 200-, 400- (T400), 800-, and 1,500-m maximal front crawl bouts to calculate CV4par. V[Combining Dot Above]O2, HR, [La], and RPE were measured immediately after bouts. Swimmers then performed 3 × 10-minute front crawl (45 seconds rest) at CV4par. V[Combining Dot Above]O2, HR, [La], and RPE were measured after 10 minutes of rest (Rest), warm-up (Pre), each 10-minute repetition, and at the end of the test (Post). CV4par was 1.33 ± 0.08 m·s. V[Combining Dot Above]O2, HR, [La], and RPE were similar between first 10-minute and Post time points in the 3 × 10-minute protocol. CV4par was equivalent to 92 ± 2% of the mean swimming speed of T400 (v400) for these swimmers. CV4par calculated through a single T400 (92%v400) showed excellent agreement (r = 0.30; 95% CI: -0.04 to 0.05 m·s, p = 0.39), low coefficient of variation (2%), and root mean square error of 0.02 ± 0.01 m·s when plotted against CV4par assessed through a 4-parameter model. These results generated the equation CV4par = 0.92 × v400. A single T400 can be used reliably to estimate the CV4par typically derived with 6 efforts in age-group swimmers.

The specificity of contemporary training practices of international rugby sevens players is unknown. We quantified the positional group-specific activity profiles and physiological demands of on-field training activities and compared these with match demands. Twenty-two international matches and 63 rugby-specific training drills were monitored in 25 backs and 17 forwards from a national squad of male rugby sevens players over a 21-month period. Drills were classified into 3 categories: low-intensity skill refining (n = 23 drills, 560 observations), moderate- to high-intensity skill refining (n = 28 drills, 600 observations), and game simulation (n = 12 drills, 365 observations). Movement patterns (via Global Positioning System devices) and physiological load (via heart rate monitors) were recorded for all activities, and the differences between training and matches were quantified using magnitude-based inferential statistics. Distance covered in total and at ≥3.5 m·s, maximal velocity, and frequency of accelerations and decelerations were lower for forwards during competition compared with those for backs by a small but practically important magnitude. No clear positional group differences were observed for physiological load during matches. Training demands exceeded match demands only for frequency of decelerations of forwards during moderate- to high-intensity skill-refining drills and only by a small amount. Accelerations and distance covered at ≥6 m·s were closer to match values for forwards than for backs during all training activities, but training drills consistently fell below the demands of international competition. Coaches could therefore improve physical and physiological specificity by increasing the movement demands and intensity of training drills.

This study determined whether body composition, strength, and power changes that occur during preseason can be maintained during an international rugby sevens season. Fourteen male international rugby sevens players (age 21.4 ± 2.2 years; mean ± SD) were categorized as forward (n = 7) or back (n = 7), and assessed for height, mass (M), skinfolds (S) (∑7), upper-body (UB) strength, lower-body (LB) strength, and LB power. Bench press, back squat, and a countermovement jump were used to measure strength and power at 3 time points: initial, early season, and late season. Forwards were taller (185 ± 4 cm), heavier (95 ± 6 kg), and possessed a greater lean body mass (55.5 ± 4.0 M·S) than backs (181 ± 8 cm, 88.5 ± 5.5 kg, and 51.9 ± 3.4 M·S). Over the full season, small (∼5 ± 5%; mean ± 90% confidence limits) positive changes occurred in body composition. Lower-body strength gained during the preseason, decayed in-season, whereas UB strength increased moderately (∼10 ± 3%) across the season. Power showed inconsistencies between measured variables with a moderate positive change across the season in mean velocity and relative peak power. Forwards showed a small decrease in peak power (relative and absolute). Moderate changes were observed in mean power over the season, forwards decreasing (∼6 ± 6%) and backs increasing (∼8 ± 6%). Rugby sevens forwards in this study found it difficult to maintain and improve power qualities in-season. Training loads of forwards and backs should be differentiated to maximize strength and power in-season.

For special populations such as people with a mental health issue or learning disability, a disconnect between the ability to accurately monitor and regulate exercise behaviour can lead to reduced levels of physical activity, which, in turn, is associated with additional physical or mental health problems. Activity pacing is a strategy used in clinical settings to address issues of pain amelioration, while self-pacing research is now well addressed in sport and exercise science literature. It has been proposed recently that these overlapping areas of investigation collectively support the development of self-regulatory, lifestyle exercise skills across broad population groups. Activity pacing appears to have substantial application in numerous development and rehabilitation settings and, therefore, the purpose of this short communication is to articulate how an activity pacing approach could be utilized among population groups in whom self-regulatory skills may require development. This paper provides specific examples of exercise practice across 2 discrete populations: children, and people with mental health and learning difficulties. In these cases, homeostatic regulatory processes may either be altered, or the individual may require extrinsic support to appropriately self-regulate exercise performance. A support-based exercise environment or approach such as programmatic activity (lifestyle) pacing would be beneficial to facilitate supervised and education-based self-regulation until such time as fully self-regulated exercise is feasible. LAY ABSTRACT Activity pacing is a practical means of supporting selfregulation in physical activity. This could be achieved through lifestyle support or in specific practical sport or physical activity situations, depending on the population. Improving the development of self-regulatory, lifestyle exercise skills across broad population groups could be helpful in addressing deficiencies in physical activity levels, which, in turn, can be associated with additional physical or mental health problems. This paper provides specific examples of pacing-based exercise practice across 2 example populations: children, and people with mental health and learning difficulties. In these cases, self-regulation processes may need to be developed, or require external support. Pacing is therefore relevant to different populations in different ways.

The provision or restriction of select nutrients in an athlete’s diet can elicit a variety of changes in fuel utilization, training adaptation, and performance outcomes. Furthermore, nutrient availability can also influence athlete health, with one key system of interest being iron metabolism. The aim of this review was to synthesize the current evidence examining the impact of dietary manipulations on the iron regulatory response to exercise. Specifically, we assessed the impact of both acute and chronic carbohydrate (CHO) restriction on iron metabolism, with relevance to contemporary sports nutrition approaches, including models of periodized CHO availability and ketogenic low CHO high fat diets. Additionally, we reviewed the current evidence linking poor iron status and altered hepcidin activity with low energy availability in athletes. A cohesive understanding of these interactions guides nutritional recommendations for athletes struggling to maintain healthy iron stores, and highlights future directions and knowledge gaps specific to elite athletes.

Although performance and biomechanical evaluations are becoming more swimming-specific, dryland testing permits monitoring of a larger number of performance-related variables. However, as the degree of comparability of measurements conducted in-water and on land conditions is unclear, we aimed to assess the differences between force production in these two different conditions. Twelve elite swimmers performed a 30 s tethered swimming test and four isokinetic tests (shoulder and knee extension at 90 and 300&deg, /s) to assess peak force, peak and average torque, and power symmetry index. We observed contralateral symmetry in all the tests performed, e.g., for 30 s tethered swimming and peak torque shoulder extension at 90&deg, /s: 178 &plusmn, 50 vs. 183 &plusmn, 56 N (p = 0.38) and 95 &plusmn, 37 vs. 94 &plusmn, 35 N &times, m (p = 0.52). Moderate to very large direct relationships were evident between dryland testing and swimming force production (r = 0.62 to 0.96, p &lt, 0.05). Swimmers maintained similar symmetry index values independently of the testing conditions (r = &minus, 0.06 to &minus, 0.41 and 0.04 to 0.44, p = 0.18&ndash, 0.88). Asymmetries in water seems to be more related to technical constraints than muscular imbalances, but swimmers that displayed higher propulsive forces were the ones with greater force values on land. Thus, tethered swimming and isokinetic evaluations are useful for assessing muscular imbalances regarding propulsive force production and technical asymmetries.

Purpose The short-term restriction of carbohydrate (CHO) can potentially influence iron regulation via modification of postexercise interleukin-6 (IL-6) and hepcidin levels. This study examined the effect of a chronic ketogenic low-CHO high-fat (LCHF) diet on iron status and iron-regulatory markers in elite athletes. Methods International-level race walkers (n = 50) were allocated to one of three dietary interventions: (i) a high-CHO diet (n = 16), (ii) a periodized CHO availability (n = 17), or (iii) an LCHF diet (n = 17) while completing a periodized training program for 3 wk. A 19- to 25-km race walking test protocol was completed at baseline and after adaptation, and changes in serum ferritin, IL-6, and hepcidin concentrations were measured. Results from high-CHO and periodized CHO were combined into one group (CHO; n = 33) for analysis. Results The decrease in serum ferritin across the intervention period was substantially greater in the CHO group (37%) compared with the LCHF (23%) group (P = 0.021). After dietary intervention, the postexercise increase in IL-6 was greater in LCHF (13.6-fold increase; 95% confidence interval [CI] = 7.1–21.4) than athletes adhering to a CHO-rich diet (7.6-fold increase; 95% CI = 5.5–10.2; P = 0.033). Although no significant differences occurred between diets, CI values indicate that 3 h postexercise hepcidin concentrations were lower after dietary intervention compared with baseline in CHO (β = −4.3; 95% CI = −6.6 to −2.0), with no differences evident in LCHF. Conclusion Athletes who adhered to a CHO-rich diet experienced favorable changes to the postexercise IL-6 and hepcidin response, relative to the LCHF group. Lower serum ferritin after 3 wk of additional dietary CHO might reflect a larger more adaptive hematological response to training.

Objectives Adhering to a low carbohydrate (CHO) high fat (LCHF) diet can alter markers of iron metabolism in endurance athletes. This investigation examined the re-introduction of CHO prior to, and during exercise on the iron-regulatory response to exercise in a homogenous (in regard to serum ferritin concentration) group of athletes adapted to a LCHF diet. Design Parallel groups design. Methods Three weeks prior to the exercise trials, twenty-three elite race walkers adhered to either a CHO-rich (n = 14) or LCHF diet (n = 9). A standardised 19–25 km race walk was performed while athletes were still adhering to their allocated dietary intervention (Adapt). A second test was performed three days later, where all athletes were placed on a high CHO diet (CHO Restoration). Venous blood samples were collected pre-, post- and 3 h post-exercise and measured for interleukin-6 (IL-6) and hepcidin-25. Results The post-exercise IL-6 increase was greater in LCHF (p < 0.001) during both the Adapt (LCHF: 13.1-fold increase; 95% CI: 5.6–23.0, CHO: 8.0-fold increase; 5.1–11.1) and CHO Restoration trials (LCHF: 18.5-fold increase; 10.9–28.9, CHO: 6.3-fold increase; 3.9–9.5); outcomes were not different between trials (p = 0.84). Hepcidin-25 concentrations increased 3 h post-exercise (p < 0.001), however, they did not differ between trials (p = 0.46) or diets (p = 0.84). Conclusions The elevated IL-6 response in athletes adapted to a LCHF diet was not attenuated by an acute increase in exogenous CHO availability. Despite diet-induced differences in IL-6 response to exercise, post-exercise hepcidin levels were similar between diets and trials, indicating CHO availability has minimal influence on post-exercise iron metabolism.

Context/Background: International-level swimmers periodize their training to qualify for major championships, then improve further at these events. However, the effects of various factors that could affect performance progressions have not been described systematically. Purpose: To quantify the pattern of change in performance between season best qualifying time and the major championships of the year and to assess the influence of time between performance peaks, ranking at the major events, stroke, event distance, sex, age, and country. Methods: A total of 7832 official competition times recorded at 4 FINA World Championships and 2 Olympic Games between 2011 and 2017 were compared with each swimmer’s season best time prior to the major event of the year. Percentage change in performance was related with the time elapsed between season best and major competition, race event, sex, age, and country using linear mixed modeling. Results: Faster performance (−0.79% [0.67%]; mean [SD]) at the major competition of the year occurred in 38% of all observations vs 62% no change or regression (1.10% [0.88%]). The timing between performance peaks (130 d) had little effect on performance progressions (P = .83). Only medal winners (−0.87% [0.91%]), finalists (−0.16% [0.97%]), and US swimmers (−0.44% [1.08%]) progressed between competitions. Stroke, event distance, sex, and age had trivial impact on performance progression. Conclusions: Performance progressions at Olympic Games and World Championships were not determined by timing between performance peaks. Performance progression at a major competition appears necessary to win a medal or make the final, independent of race event, sex, and age.

Carbohydrate (CHO) availability could alter mucosal immune responses to exercise. This study compared the effect of three dietary approaches to CHO availability on resting and post-exercise s-IgA levels. Elite race walkers (n = 26) adhered to a high CHO diet (HCHO), periodised CHO availability (PCHO) or a low CHO/high fat diet (LCHF) for 3 weeks while completing an intensified training program. HCHO and PCHO groups consumed 8.0–8.5 g.kg−1 CHO daily, with timing of ingestion manipulated to alter CHO availability around key training sessions. The LCHF diet comprised 80% fat and restricted CHO to < 50 g.day−1. A race walk test protocol (19 km females, 25 km males) was completed at baseline, after adaptation, and following CHO restoration. On each occasion, saliva samples were obtained pre- and post-exercise to quantify s-IgA levels. Resting s-IgA secretion rate substantially increased ~ two-fold post-intervention in all groups (HCHO: 2.2 ± 2.2, PCHO: 2.8 ± 3.2, LCHF: 1.6 ± 1.6; fold-change± 95% confidence limits), however, no substantial differences between dietary treatments were evident. Post-exercise, substantial 20–130% increases in s-IgA concentration and 43–64% reductions in flow rate occurred in all dietary treatments, with trivial differences evident between groups. It appears that high volume training overrides any effect of manipulating CHO availability on mucosal immunity in elite athletes.

Zacca, R, Azevedo, R, Chainok, P, Vilas-Boas, JP, Castro, FAdS, Pyne, DB, and Fernandes, RJ. Monitoring age-group swimmers over a training macrocycle: energetics, technique, and anthropometrics. J Strength Cond Res 34(3): 818-827, 2020-The aim of this study was to quantify changes and contributions of energetic, technique, and anthropometric profiles across the first training macrocycle (16-week) in a traditional 3-peak swimming season. Twenty-four age-group swimmers (10 boys and 14 girls age 14.4 ± 0.9 years) of equal maturational stage were monitored through a 400-m test in front crawl (T400). Energetic, technique, and anthropometric characteristics were compared before (experimental testing 1, E1) and after the preparatory (E2), specific (E3), and competitive (E4) training periods. Sex interaction was not significant for any variable. Multiple linear regressions and principal component analysis were used to identify the most influential variables and the relative contribution of each domain (energetics, technique, and anthropometrics) to changes in swimming performance of T400. The relative contributions for performance of T400 at E1, E2, E3, and E4 were 15, 12, 6, and 13% for energetics, 78, 85, 75, and 70% for technique, and 7, 3, 19 and 17% for anthropometrics, respectively. Technique played the main role during the first 16-week macrocycle in a competitive season, regardless of small fluctuations in the influence of energetics and anthropometrics. Changes and influence of energetics, technique, and anthropometric on age-group swimmers' performance could be described by the T400 swimming test, providing a comprehensive biophysical overview of the main contributors to swimming performance.

To determine the validity of the lactate threshold (LT) and maximal oxygen uptake ([Formula: see text]) determined during graded exercise test (GXT) of different durations and using different LT calculations. Trained male cyclists (n = 17) completed five GXTs of varying stage length (1, 3, 4, 7 and 10 min) to establish the LT, and a series of 30-min constant power bouts to establish the maximal lactate steady state (MLSS). [Formula: see text] was assessed during each GXT and a subsequent verification exhaustive bout (VEB), and 14 different LTs were calculated from four of the GXTs (3, 4, 7 and 10 min)-yielding a total 56 LTs. Agreement was assessed between the highest [Formula: see text] measured during each GXT ([Formula: see text]) as well as between each LT and MLSS. [Formula: see text] and LT data were analysed using mean difference (MD) and intraclass correlation (ICC).The [Formula: see text] value from GXT1 was 61.0 ± 5.3 mL.kg-1.min-1 and the peak power 420 ± 55 W (mean ± SD). The power at the MLSS was 264 ± 39 W. [Formula: see text] from GXT3, 4, 7, 10 underestimated [Formula: see text] by ~1-5 mL.kg-1.min-1. Many of the traditional LT methods were not valid and a newly developed Modified Dmax method derived from GXT4 provided the most valid estimate of the MLSS (MD = 1.1 W; ICC = 0.96).The data highlight how GXT protocol design and data analysis influence the determination of both [Formula: see text] and LT. It is also apparent that [Formula: see text] and LT cannot be determined in a single GXT, even with the inclusion of a VEB.

Jones, JV, Pyne, DB, Haff, GG, and Newton, RU. Comparison between elite and subelite swimmers on dry land and tumble turn leg extensor force-time characteristics. J Strength Cond Res 32(6): 1762-1769, 2018-Elite swimmers demonstrate faster swimming turn times that are potentially a result of having better strength-power characteristics than subelite swimmers. We quantified differences between dry-land and swimming turn force-time characteristics in elite swimmers and subelite swimmers. Subelite (11 males: 17.4 ± 0.6 years; 10 females: 17.1 ± 0.6 years) and elite swimmers (15 male: 23.2 ± 2.3 years; 7 female: 21.6 ± 2.5 years) were tested in a cross-sectional design. All swimmers performed a body weight and loaded (20 kg females, 30 kg males) squat jump (SJ) on a portable force platform. On the same day, all swimmers completed swimming turn analyses using a force platform fixed within the pool wall. The magnitude of difference between groups was estimated using a standardized mean difference (effect size statistic). Elite male and female swimmers had superior swimming turn and dry-land force-time characteristics to subelite swimmers in all tests. The standardized mean differences between groups ranged from small to very large. The largest differences were SJ peak velocity unloaded (3.07 ± 1.0 m·s males, 3.49 ± 2.29 m·s females; standardized mean difference ± 90% confidence limits) and SJ peak power unloaded (2.59 ± 0.79 w male, 2.80 ± 1.64 w female) with elite male and female swimmers having a ∼25-50% higher performance than the subelites in both characteristics. Elite swimmers exhibit superior strength and power characteristics for the swimming turn compared with younger and less experienced swimmers. A well-planned and executed strength and conditioning program is needed for emerging swimmers to develop these qualities, as they transition to senior levels.

Pacing strategy, or how energy is distributed during exercise, can substantially impact athletic performance and is considered crucial for optimal performance in many sports. This is particularly true in swimming given the highly resistive properties of water and low mechanical efficiency of the swimming action. The aim of this systematic review was to determine the pacing strategies utilised by competitive swimmers in competition and their reproducibility, and to examine the impact of different pacing strategies on kinematic, metabolic and performance variables. This will provide valuable and practical information to coaches and sports science practitioners. The databases Web of Science, Scopus, SPORTDiscus and PubMed were searched for published articles up to 1 August 2017. A total of 23 studies examining pool-based swimming competitions or experimental trials in English-language and peer-reviewed journals were included in this review. In short- and middle-distance swimming events maintenance of swimming velocity is critical, whereas in long-distance events a low lap-to-lap variability and the ability to produce an end spurt in the final lap(s) are key. The most effective strategy in the individual medley (IM) is to conserve energy during the butterfly leg to optimise performance in subsequent legs. The pacing profiles of senior swimmers remain relatively stable irrespective of opponents, competition stage or type, and performance time. Implementing event-specific pacing strategies should benefit the performance of competitive swimmers. Given differences between swimmers, there is a need for greater individualisation when considering pacing strategy selection across distances and strokes.

Wen, N, Dalbo, VJ, Burgos, B, Pyne, DB, and Scanlan, AT. Power testing in basketball: Current practice and future recommendations. J Strength Cond Res 32(9): 2686-2700, 2018-Numerous foundational movements performed during basketball are predicated on underlying power-related attributes, including speed, change-of-direction (COD), and jumping. Accordingly, fitness testing batteries for basketball have incorporated an assortment of linear speed tests, COD tests, and jump tests. However, because of the wide variety of testing options, it is difficult for basketball practitioners to select appropriate testing protocols for the assessment of power-related attributes. As a result, there is a need to review the relevant literature to identify game-specific, power-related attributes important in basketball and the most appropriate tests available to assess power-related attributes for basketball practitioners. Therefore, the aims of this review were to: (a) identify essential power-related attributes important in basketball; (b) discuss the suitability of common and novel power-related tests; and (c) provide recommendations for future research and best practice approaches for basketball coaching staff. In this review, we propose a series of novel tests that are more targeted and specific to basketball movements including: (a) 5- and 10-m linear sprints, (b) modified agility T-test, (c) change-of-direction deficit (CODD), (d) lateral bound, (e) Sargent jump, (f) one-step jump, and (g) isometric midthigh pull test. Improved testing of power-related attributes should enable basketball practitioners to develop targeted training plans for enhancing player performance.

Upper respiratory illness is the most common reason for non‐injury‐related presentation to a sports medicine clinic, accounting for 35–65% of illness presentations. Recurrent or persistent respiratory illness can have a negative impact on health and performance of athletes undertaking high levels of strenuous exercise. The cause of upper respiratory symptoms (URS) in athletes can be uncertain but the majority of cases are related to common respiratory viruses, viral reactivation, allergic responses to aeroallergens and exercise‐related trauma to the integrity of respiratory epithelial membranes. Bacterial respiratory infections are uncommon in athletes. Undiagnosed or inappropriately treated asthma and/or allergy are common findings in clinical assessments of elite athletes experiencing recurrent URS. High‐performance athletes with recurrent episodes of URS should undergo a thorough clinical assessment to exclude underlying treatable conditions of respiratory inflammation. Identifying athletes at risk of recurrent URS is important in order to prescribe preventative clinical, training and lifestyle strategies. Monitoring secretion rates and falling concentrations of salivary IgA can identify athletes at risk of URS. Therapeutic interventions are limited by the uncertainty of the underlying cause of inflammation. Topical anti‐inflammatory sprays can be beneficial for some athletes. Dietary supplementation with bovine colostrum, probiotics and selected antioxidants can reduce the incidence or severity of URS in some athletes. Preliminary studies on athletes prone to URS indicate a genetic predisposition to a pro‐inflammatory response and a dysregulated anti‐inflammatory cytokine response to intense exercise as a possible mechanism of respiratory inflammation. This review focuses on respiratory infections and inflammation in elite/professional athletes., The February 2016 issue contains a Special Feature on the Effects of exercise on the immune system and metabolism coming into the Olympic year. The role of the immune system in exercise is complex and challenging. Too little exercise can depress the immune system. In contrast, too much exercise can also lead to a compromised immune system. This is a challenge that athletes face as they prepare for competition. Immunology & Cell Biology thanks the coordinators of this Special Feature ‐ Mark Febbraio and Graeme Lancaster ‐ for their planning and input.

AB Purpose: A bioenergetical analysis of different exercise modes near maximal oxygen consumption (V[spacing dot above]O2max) intensity is scarce, hampering the prescription of training to enhance performance. We assessed the time sustained in swimming, rowing, running, and cycling at an intensity eliciting V[spacing dot above]O2max and determined the specific oxygen uptake (V[spacing dot above]O2) kinetics and total energy expenditure (Etot-tlim). Methods: Four subgroups of 10 swimmers, 10 rowers, 10 runners, and 10 cyclists performed (i) an incremental protocol to assess the velocity (vV[spacing dot above]O2max) or power (wV[spacing dot above]O2max) associated with V[spacing dot above]O2max and (ii) a square wave transition exercise from rest to vV[spacing dot above]O2max/wV[spacing dot above]O2max to assess the time to voluntary exhaustion (Tlim-100%V[spacing dot above]O2max). The V[spacing dot above]O2 was measured using a telemetric portable gas analyzer (K4b2, Cosmed, Rome, Italy) and V[spacing dot above]O2 kinetics analyzed using a double exponential curve fit. Etot-tlim was computed as the sum of its three components: aerobic (Aer), anaerobic lactic (Analac), and anaerobic alactic (Anaalac) contributions. Results: No differences were evident in Tlim-100% V[spacing dot above]O2max between exercise modes (mean +/- SD: swimming, 187 +/- 25; rowing, 199 +/- 52; running, 245 +/- 46; and cycling, 227 +/- 48 s). In contrast, the V[spacing dot above]O2 kinetics profile exhibited a slower response in swimming (21 +/- 3 s) compared with the other three modes of exercise (rowing, 12 +/- 3; running, 10 +/- 3; and cycling, 16 +/- 4 s) (P < 0.001). Etot-tlim was similar between exercise modes even if the Analac contribution was smaller in swimming compared with the other sports (P < 0.001). Conclusion: Although there were different V[spacing dot above]O2 kinetics and ventilatory patterns, the Tlim-100%V[spacing dot above]O2max was similar between exercise modes most likely related to the common central and peripheral level of fitness in our athletes.

AB Purpose: The objective of this study is to investigate the relation between sport training and the risk of common illnesses: upper respiratory tract and pulmonary infections (URTPI), muscular affections (MA), and all-type pathologies in highly trained swimmers. Methods: Twenty-eight French professional swimmers were monitored weekly for 4 yr. Training variables included 1) in-water and dryland intensity levels: low-load, high-load, resistance, maximal strength, and general conditioning training (expressed as the percentage of the maximal load performed by each subject, at each intensity level over the study period); and 2) training periods: moderate, intensive, taper, competition, and postcompetition. Illnesses were diagnosed by a sports physician using a standardized questionnaire. Mixed-effects logistic regression analyses were used to model odds ratios for the association between common illnesses and training variables, adjusted for sport season, semiseason (summer or winter), age, competition level, sex, and history of recent events, whereas controlling for heterogeneity among swimmers. Results: The risk of common illnesses was significantly higher in winter months, for national swimmers (for URTPI), and in cases of history of recent event (notably for MA). The odds of URTPI increased 1.08 (95% CI, 1.01-1.16) and 1.10 (95% CI, 1.01-1.19) times for every 10% increase in resistance and high-load trainings, respectively. The odds of MA increased by 1.49 (95% CI, 1.14-1.96) and 1.63 (95% CI, 1.20-2.21) for each 10% increase in high load and general conditioning training, respectively. The odds of illnesses were 50%-70% significantly higher during intensive training periods. Conclusion: Particular attention must be paid to illness prevention strategies during periods of intensive training, particularly in the winter months or in case of the recent medical episode.

Purpose: To compare the dynamics of maximal oxygen uptake (), blood lactate ([La]b), total energy expenditure (Etot), and contributions of the aerobic (Eaer), alactic anaerobic (Ean,al), and lactic anaerobic (Ean,lac) metabolic energy pathways over 4 consecutive 25-m laps (L0–25, L25–50, etc) of a 100-m maximal freestyle swim. Methods: Elite swimmers comprising 26 juniors (age = 16 [1] y) and 23 seniors (age = 24 [5] y) performed 100 m at maximal speed and then 3 trials (25, 50, and 75 m) at the same pace as that of the 100 m. [La]b was collected, and was measured 20 s postexercise. Results: The estimated energetic contributions for the 100-m trial are presented as mean (SD): Eaer, 51% (8%); Ean,al, 18% (2%); Ean,lac, 31% (9%). increased from L0–25 to L25–50 (mean = 3.5 L·min−1; 90% confidence interval [CI], 3.4–3.7 L·min−1 to mean = 4.2 L·min−1; 90% CI, 4.0–4.3 L·min−1) and then stabilized in the 2nd 50 m (mean = 4.1 L·min−1; 90% CI, 3.9–4.3 L·min−1 to mean = 4.2 L·min−1; 90% CI, 4.0–4.4 L·min−1). Etot (juniors, 138 [18] kJ; seniors, 168 [26] kJ), Ean,al (juniors, 27 [3] kJ; seniors, 30 [3] kJ), and Ean,lac (juniors, 38 [12] kJ; seniors, 62 [24] kJ) were 11–58% higher in seniors. Faster swimmers (n = 26) had higher , 90% CI 4.4–4.8 L·min−1 vs 3.9 L·min−1, 90% CI 3.6–4.2 L·min−1), and Eaer power was associated with fast performances (P Conclusion: Faster swimmers were characterized by higher and less time to reach the highest at ∼50 m of the 100-m swim. Anaerobic qualities become more important with age.

Critical speed (CS) testing is useful in monitoring training in swimmers, however, completing a series of time trials (TTs) regularly is time-consuming. The 3-minute test may be a solution with positive initial findings. This investigation examined whether a modified 3-minute test (12 × 25 m) could assess CS and supra-CS distance capacity (D') in swimmers. A series of 12 × 25 m intervals were completed unpaced at maximal effort, interspersed with 5 s rest periods. The model speed = a e

Background Australian football (AF) players require endurance, strength, speed, and agility to be successful. Tests assessing physical characteristics are commonly used for talent identification; however, their ability to differentiate between players across the Australian Football League’s (AFL) participation pathway remains unclear. The objective of this review was to quantify the physical characteristics of male AF players across the AFL participation pathway. Methods A search of databases was undertaken. Studies examining tests of physical performance were included, with 27 meeting the inclusion/exclusion criteria. Study appraisal was conducted using a checklist of selection criteria. Results The 20-m sprint time was the most reported test, followed by vertical jump (VJ), AFL planned agility, and 20-m multi-stage fitness test (MSFT). The fastest times for 20-m sprint were for Elite AFL players (range 2.94–3.13 s), with local-level players the slowest (3.22–4.06 s). State Junior Under (U) 18s (58–66 cm) had higher jumps than senior players, with the lowest jumps reported for Local U10s (mean 31 cm). No elite-level data were reported for the AFL planned agility or 20-m MSFT. AFL planned agility times were only reported for talent pathway levels, with large performance variability evident across all levels (8.17–9.12 s). Only mean 20-m MSFT scores were reported from Local U10s to National Draft Camp (6.10–13.50 shuttles). Conclusions Talent pathway players exhibit similar mean test scores irrespective of the physical test, with the exception of 20-m sprint and VJ. Physical tests can discriminate between local participation level players but are less useful within the AFL talent pathway.

To study the variability in stroking parameters between and within laps and individuals during competitions, we compared and modeled the changes of speed, stroke rate, and stroke length in 32 top-level male and female swimmers over 4 laps (L1–L4) in 200-m freestyle events using video-derived 2-dimensional direct linear transformation. For the whole group, speed was greater in L1, with significant decreases across L2, L3, and L4 (1.80 ± 0.10 vs 1.73 ± 0.08; 1.69 ± 0.09; 1.66 ± 0.09 · s−1, P P −1, P P P

ObjectiveEstablish 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.MethodsOlympic 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.ResultsThe 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).ConclusionsAll 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.

Exercise and sport sciences continue to grow as a collective set of disciplines investigating a broad array of basic and applied research questions. Despite the progress, there is room for improvement. A number of problems pertaining to reliability and validity of research practices hinder advancement and the potential impact of the field. These problems include inadequate validation of surrogate outcomes, too few longitudinal and replication studies, limited reporting of null or trivial results, and insufficient scientific transparency. The purpose of this review is to discuss these problems as they pertain to exercise and sport sciences based on their treatment in other disciplines, namely psychology and medicine, and to propose a number of solutions and recommendations.

Zacca, R, Azevedo, R, Peterson Silveira, R, Vilas-Boas, JP, Pyne, DB, Castro, FAdS, and Fernandes, RJ. Comparison of incremental intermittent and time trial testing in age-group swimmers. J Strength Cond Res 33(3): 801-810, 2019-The aim of this study was to compare physiological and biomechanical characteristics between an incremental intermittent test and a time trial protocol in age-group swimmers. Eleven national level age-group swimmers (6 men and 5 women) performed a 7 × 200-m incremental intermittent protocol (until exhaustion; 30-second rest) and a 400-m test (T400) in front crawl on separate days. Cardiorespiratory variables were measured continuously using a telemetric portable gas analyzer. Swimming speed, stroke rate, stroke length, and stroke index were assessed by video analysis. Physiological (oxygen uptake, heart rate, and lactate concentrations) and biomechanical variables between seventh 200-m step (in which the minimal swimming speed that elicits maximal oxygen uptake-vV[Combining Dot Above]O2max was identified) and T400 (time trial/fixed distance) were compared with a paired student's t test, Pearson's product-moment correlation, Passing-Bablok regression, and Bland-Altman plot analyses. There were high level of agreement and high correlations (r-values ∼0.90; p ≤ 0.05) for all physiological variables between the seventh 200-m step and T400. Similarly, there were high level of agreements and high correlations (r-values ∼0.90; p ≤ 0.05) for all biomechanical variables and only trivial bias in swimming speed (0.03 m·s; 2%). Primary physiological and biomechanical responses between incremental intermittent and representative time trial protocols were similar, but best practice dictates protocols should not be used interchangeably to minimize errors in prescribing swimming training speeds. The T400 is a valid, useful, and easier to administer test for aerobic power assessment in age-group swimmers.

BACKGROUND Given the likely influence that high training loads, contact-induced hemolysis and female-specific requirements have on the incidence of iron deficiency, characterizing the direction and magnitude of fluctuations in iron status over an international season is important for managing player health and physical performance in rugby sevens. METHODS Australian national male (N.=27) and female (N.=23) rugby sevens players undertook blood tests at pre-season, mid-season, and end-season. Hemoglobin (Hb), hematocrit (Hct), ferritin, transferrin and transferrin saturation were quantified. Female athletes also reported oral contraceptive use and a subset (N.=7) provided 7-day food diaries to quantify iron intake. RESULTS Male players typically had a three-fold higher ferritin concentration than females. Pre-season ferritin concentrations in male (151±66 µg/L) and female (51±24 µg/L) players declined substantially (~20%) by mid-season but recovered by end-season. Over the season 23% of female players were classified as iron deficient (ferritin

Clinical and laboratory identification of the underlying risk of respiratory illness in athletes has proved problematic. The aim of this study was to determine whether clinical data, combined with immune responses to standardised exercise protocols and genetic cytokine polymorphism status, could identify the risk of respiratory illness (symptoms) in a cohort of highly-trained athletes. Male endurance athletes (n=16; VO2max 66.5 ± 5.1 mL.kg-1.min-1) underwent a clinical evaluation of known risk factors by a physician and comprehensive laboratory analysis of immune responses both at rest and after two cycling ergometer tests: 60 min at 65% VO2max (LONG); and 6 x 3 min intervals at 90% VO2max (INTENSE). Blood tests were performed to determine Epstein Barr virus (EBV) status and DNA was genotyped for a panel of cytokine gene polymorphisms. Saliva was collected for measurement of IgA and detection of EBV DNA. Athletes were then followed for 9 months for self-reported episodes of respiratory illness, with confirmation of the underlying cause by a sports physician. There were no associations with risk of respiratory illness identified for any parameter assessed in the clinical evaluations. The laboratory parameters associated with an increased risk of respiratory illnesses in highly-trained athletes were cytokine gene polymorphisms for the high expression of IL-6 and IFN-ɣ; expression of EBV-DNA in saliva; and low levels of salivary IgA concentration. A genetic risk score was developed for the cumulative number of minor alleles for the cytokines evaluated. Athletes prone to recurrent respiratory illness were more likely to have immune disturbances that allow viral reactivation, and a genetic predisposition to pro-inflammatory cytokine responses to intense exercise.

Extreme environmental conditions present athletes with diverse challenges; however, not all sporting events are limited by thermoregulatory parameters. The purpose of this leading article is to identify specific instances where hot environmental conditions either compromise or augment performance and, where heat acclimation appears justified, evaluate the effectiveness of pre-event acclimation processes. To identify events likely to be receptive to pre-competition heat adaptation protocols, we clustered and quantified the magnitude of difference in performance of elite athletes competing in International Association of Athletics Federations (IAAF) World Championships (1999-2011) in hot environments (25 °C) with those in cooler temperate conditions (25 °C). Athletes in endurance events performed worse in hot conditions (~3 % reduction in performance, Cohen's d0.8; large impairment), while in contrast, performance in short-duration sprint events was augmented in the heat compared with temperate conditions (~1 % improvement, Cohen's d0.8; large performance gain). As endurance events were identified as compromised by the heat, we evaluated common short-term heat acclimation (≤7 days, STHA) and medium-term heat acclimation (8-14 days, MTHA) protocols. This process identified beneficial effects of heat acclimation on performance using both STHA (2.4 ± 3.5 %) and MTHA protocols (10.2 ± 14.0 %). These effects were differentially greater for MTHA, which also demonstrated larger reductions in both endpoint exercise heart rate (STHA: -3.5 ± 1.8 % vs MTHA: -7.0 ± 1.9 %) and endpoint core temperature (STHA: -0.7 ± 0.7 % vs -0.8 ± 0.3 %). It appears that worthwhile acclimation is achievable for endurance athletes via both short-and medium-length protocols but more is gained using MTHA. Conversely, it is also conceivable that heat acclimation may be counterproductive for sprinters. As high-performance athletes are often time-poor, shorter duration protocols may be of practical preference for endurance athletes where satisfactory outcomes can be achieved.

Probiotic supplementation has traditionally focused on gut health. However, in recent years, the clinical applications of probiotics have broadened to allergic, metabolic, inflammatory, gastrointestinal and respiratory conditions. Gastrointestinal health is important for regulating adaptation to exercise and physical activity. Symptoms such as nausea, bloating, cramping, pain, diarrhoea and bleeding occur in some athletes, particularly during prolonged exhaustive events. Several studies conducted since 2006 examining probiotic supplementation in athletes or highly active individuals indicate modest clinical benefits in terms of reduced frequency, severity and/or duration of respiratory and gastrointestinal illness. The likely mechanisms of action for probiotics include direct interaction with the gut microbiota, interaction with the mucosal immune system and immune signalling to a variety of organs and systems. Practical issues to consider include medical and dietary screening of athletes, sourcing of recommended probiotics and formulations, dose-response requirements for different probiotic strains, storage, handling and transport of supplements and timing of supplementation in relation to travel and competition.

Background and aims The immune mechanisms by which probiotics reduce susceptibility to upper respiratory tract illness is uncertain. The aim of this study was to examine purported cell-mediated immune mechanisms that might explain the reduction in respiratory illness observed following daily supplementation with Bifidobacterium animalis subsp. lactis Bl-04 (Bl-04) and a combined Lactobacillus acidophilus NCFM & B. animalis subsp. lactis BI-07 (NCFM & Bi-07). Methods A cohort of 144 healthy physically active individuals were allocated to daily supplementation consumed as a beverage with Bl-04 (n = 46) supplemented at a dosage of 2.0 × 109 colony forming units (cfu) per day, NCFM & Bi-07 (n = 47) at a dosage of 5.0 × 109 CFU per day each, or a placebo (n = 51) over 150 d. Markers included plasma cytokines, metalloproteinases and neurotrophins, peripheral blood leucocyte numbers, antibody-dependent and antibody-independent NK cell activity (NKCA), and peripheral blood mononuclear cell (PBMC) phagocytosis. Results A total of 125 subjects were included in the final analysis. No significant effects were observed on cytokines, on white cell differentials, NKCA or PBMC phagocytosis from pre- to post-supplementation. The biomarkers that increased significantly from pre- to post-supplementation were the concentration of plasma macrophage inflammatory protein (MIP)-1δ which was higher in the Bl-04 than placebo group (Bl-04 25% ± 11%, placebo −3.3% ± 9.4%; mean ± SD, P = 0.003) while the concentration of plasma matrix metallo-proteinase (MMP)-1 decreased by 11% ± 16% in the NCFM & Bi-07 group and increased by 21% ± 17% in the placebo group, which was a significant 26% difference (8–41%; P = 0.02). Conclusion Probiotic supplementation had little effect on parameters of the innate immune system. Mechanisms explaining the beneficial effect of Bl-04 or NCFM & Bi-07 supplementation on respiratory illness remain unclear.

The effectiveness of human movement is the culmination of several musculoskeletal factors; asymmetry in movement could reduce optimal performance. The aims of this study were to quantify relationships between bilateral hand-force production, swimming performance, and the influence of fatigue. Paralympic swimmers (n=21, aged 20.9 ± 4.7 yr) were categorised into no, high- and low-range physical disability groups and performed two 100 m time trials to measure swimming performance. Bilateral hand-force was measured over two 60 s maximal tests on a swim-bench ergometer to quantify the degree of asymmetry. Large relationships between mean force and swimming velocity were seen for both the high- (r=0.62, ±0.45; r-value, ±90% confidence limits) and low-range (r=0.62, ±0.50) groups. Asymmetry was related to level of disability, with the smallest difference of 6.7, ±2.6 N in the no-musculoskeletal disability group. This difference increased to 13.1, ±10.0 N and 13.5, ±16.2 N in the high- and low-range groups. Between the first and last 15 s of the swim-bench test, reductions in mean force were small for the physical disabilities groups. Similarly, changes in asymmetry were small for both the no-physical and low-range groups. Paralympic swimmers with a more severe physical impairment typically generate substantially lower force and velocity.

The aim of the study was to assess the differences in maximal isometric trunk extension and flexion strength during standing, sitting and kneeling. Additionally, we were interested in correlations between the maximal strength in sagittal, frontal and transverse plane, measured in the sitting position. Sixty healthy subjects (24 male, 36 female; age 41.3 ± 15.1 yrs; body height 1.70 ± 0.09 m; body mass 72.7 ± 13.3 kg) performed maximal voluntary isometric contractions of the trunk flexor and extensor muscles in standing, sitting and kneeling position. The subjects also performed lateral flexions and rotations in the sitting position. Each task was repeated three times and average of maximal forces was used for data analysis. RANOVA with post-hoc testing was applied to the flexion and extension data. The level of statistical significance was set to p < 0.05. Overall, in both genders together, the highest average force for trunk extension was recorded in sitting posture (910.5 ± 271.5 N), followed by kneeling (834.3 ± 242.9 N) and standing (504.0 ± 165.4 N), compared with flexion, where we observed the opposite trend (508.5 ± 213.0 N, 450.9 ± 165.7 N and 443.4 ± 153.1 N, respectively). Post-hoc tests showed significant differences in all extension positions (p < 0.0001) and between sitting/standing (p = 0.018) and kneeling/standing (p = 0.033) flexion exertions. The extension/flexion ratio for sitting was 2.1 ± 0.4, for kneeling 1.9 ± 0.4, followed by standing, where motion forward approximately equals motion backward (1.1 ± 0.6). Trunk sagittal-transverse strength showed the strongest correlation, followed by frontal-transverse and sagittal-frontal plane correlation pairs (R2 = 0.830, 0.712 and 0.657). The baseline trunk isometric strength data provided by this study should help further strength diagnostics, more precisely, the prevention of low back disorders.

PURPOSE: To investigate the impact of CHO re-introduction in athletes previously adapted to a LCHF diet on subsequent inflammatory and hepcidin responses to exercise. METHODS: In the three weeks prior to the exercise trials, twenty-three elite race walkers adhered to either a CHO-rich (n=14) or LCHF diet (n=9). A 19-25 km race walking protocol was performed while the race walkers were still adhering to their allocated dietary intervention (Adapt). A second exercise test was performed three days later, where the LCHF consumed CHO 2 h prior to, and during the exercise protocol (in line with sports nutrition guidelines) for the first time in 3.5 weeks (CHO Restoration). Venous blood samples were collected pre-, post- and 3 h post-exercise and analysed for serum ferritin, interleukin-6 (IL-6) and hepcidin-25. RESULTS: Serum ferritin concentration was similar between trials (p=0.48) and dietary groups (p=0.93). The post-exercise IL-6 increase was greater in LCHF (p