Exploring rugby coaches perception and implementation of performance analytics.

Professional coaches commonly rely on performance analysis and metrics to help make decisions regarding their practices, selection and tactics. However, few studies to date have explored coaches' perspectives of performance analysts successful integration into the high-performance environment. The aim of this study was to investigate coaches' philosophies surrounding performance analysis and how they perceived analysts could support and implement these approaches into coaching practices and match preparation. Semi-structured interviews were conducted with five professional elite level Rugby Union coaches to investigate their perceptions of performance analysis, and the contribution of performance analysts to the high-performance environment. Results revealed three main dimensions, including the role, purpose, and desired attributes of a performance analyst. Firstly, the role of the analyst was described in terms of being an information specialist, who collects, filters, and delivers information to stakeholders, and a generalist, who helps coaches utilise technology. Secondly, the purpose of the analyst was described in terms of providing both accountability and support for coaches and players. Finally, the attributes needed of an analyst included the ability to form a close relationship with coaches, communicate complex information in meaningful ways, and who was proactive, innovative, and creative when tasked with delivering information. The findings highlighted the crucial roles, purposes, and attributes of a performance analyst within high-performance Rugby Union identified by coaches and the importance of the coach-analyst relationship to support these dimensions.

Effects of Periodized vs. Nonperiodized Resistance Training on Army-Specific Fitness and Skills Performance.

Heilbronn, BE, Doma, K, Gormann, D, Schumann, M, and Sinclair, WH. Effects of periodized vs. nonperiodized resistance training on army-specific fitness and skills performance. J Strength Cond Res 34(3): 738-753, 2020-This study investigated the effects of periodized resistance training (PRD) and nonperiodized resistance training (NPRD) on army-specific fitness and skills performance measures. Forty-nine serving members of the Australian Army were randomly assigned to 1 of 3 training groups: PRD, NPRD, or no-resistance training (NRT). Resistance training (RT) was performed during PRD and NPRD twice a week for 9 weeks, over a 15-week period, as part of a structured strength and conditioning program. Baseline, mid- and post-testing measures included anthropometric, strength, and army-specific outcome measures. Results indicated that participants who undertook RT significantly improved in 3 repetition maximum (3RM) squat, deadlift, and floor press for both RT groups, at mid- and post-testing (p < 0.05), when compared with NRT. Significant improvements were also observed in 5-km weight load marching postintervention similarly for PRD (p < 0.05) and NPRD (p < 0.01) and simulated fire and movement for both RT groups at both time points (p < 0.01), compared with the NRT group (p > 0.05). Although little difference was observed between periodization models, the current findings suggest greater advantage in developing army-specific performances if a structured RT protocol is included in a generic physical training program compared with a NRT protocol. Therefore, a structured RT program should be considered for military personnel aiming to optimize army-specific fitness and skills performance.

Analysis of Cricket Ball Type and Innings on State Level Cricket Batter's Performance.

Background: The aim of this investigation was to compare the type of cricket balls utilized and innings on cricket batting performance in the First-Class Australian competition. Methods: Batting performance measures of 43 state level cricket batters were collected from two seasons of the Sheffield shield tournament (N = 60 games) that incorporated both Kookaburra™ (n = 30 games) and Duke™ (n = 30 games) cricket balls. Results: First-innings batting performances were significantly greater for the average number of runs scored (37.5 ± 13.4 vs. 31.2 ± 11.3), balls faced (60.7 ± 26.2 vs. 49.9 ± 23.6), boundary 4s (3.8 ± 1.9 vs. 2.9 ± 1.4), and boundary 6s (0.2 ± 0.3 vs. 0.1 ± 0.3) scored per game (p < 0.05), as well as centuries scored (5.74 ± 8.56 vs. 1.49 ± 5.14%) compared to second innings performances (p < 0.05). There were no differences for any batting performance measures as a result of ball type (p > 0.05). However, significantly more wickets were taken by pace bowlers during Duke™ ball games (85.0 ± 12.8 vs. 76.4 ± 13.9%), while relatively more wickets were taken by spin bowlers during Kookaburra™ ball games (14.2 ± 12.5 vs. 22.0 ± 14.1%; p < 0.05). Conclusions: Cricket batting performance was comparable in games involving the Kookaburra™ or Duke™ ball. However, pace bowlers were more successful transferring their skill to the Duke™ ball, while spin bowlers were more successful with the KB™ ball. Subsequently, batters may be able to effectively adapt their movement technique, and transfer their skill to the Duke™ ball conditions. Future research is suggested to examine the influence of the cricket playing surface's deterioration on cricket batter's interceptive performance.

Physical, Anthropometric, and Athletic Movement Qualities Discriminate Development Level in a Rugby League Talent Pathway.

Pearce, LA, Sinclair, WH, Leicht, AS, and Woods, CT. Physical, anthropometric, and athletic movement qualities discriminate development level in a rugby league talent pathway. J Strength Cond Res 32(11): 3169-3176, 2018-This study compared the physical, anthropometric, and athletic movement qualities of talent-identified rugby league (RL) players within a development pathway. From a total of 174 players, 3 developmental levels were defined: under 18 (U18; n = 52), under 20 (U20; n = 53), and state league (SL; n = 69). All players performed a test battery that consisted of 5 physical assessments, 2 anthropometric measurements, and an athletic movement assessment. A multivariate analysis of variance modeled the main effect of developmental level (3 levels: U18, U20, and SL) on test criterion variables. Receiver-operating characteristic (ROC) curves were then built for the criterion variables that showed a significant developmental level effect. A significant effect was noted (V = 0.775, F = 5.43, p ≤ 0.05), with the SL players outperforming their U18 and U20 counterparts for measures of body mass, peak and average lower limb power, double lunge (left side), single-leg Romanian deadlift (left and right sides), the push-up, and total athletic ability assessment score (p ≤ 0.05; d = 0.35-1.21). The ROC curves generated an area under the curve of greater than 65% for each test criterion, indicating greater than chance discrimination. These results highlight the physical, anthropometric, and athletic movement qualities discriminant of development level within a RL talent pathway. Practitioners are encouraged to consider the thresholds from the ROC curves as an objective guide to assist with the development of physical performance qualities that may augment player progression in Australian RL.

Heart rate variability responses to acute and repeated postexercise sauna in trained cyclists.

Short- to medium-term (i.e., 4-14 days) heating protocols induce physiological adaptations including improved cardiac autonomic modulations, as assessed using heart rate variability, which may contribute to greater exercise performance. Whether similar cardiac autonomic changes occur during an intense heating protocol (sauna) reported to increase plasma volume in athletes remains to be confirmed. This study examined changes in heart rate and its variability during a single extreme heat (sauna) exposure and repeated exposures in athletes. Six well-trained male cyclists undertook sauna bathing (30 min, 87 °C, 11% relative humidity) immediately after normal training over 10 consecutive days. Heart rate recordings were obtained during each sauna bout. Heart rate and its variability (natural logarithm of root mean square of successive differences, lnRMSSD) were analysed during 10-min periods within the first bout, and changes in heart rate and lnRMSSD were analysed during each bout via magnitude-based inferences. During the first sauna bout, heart rate was almost certainly increased (∼32%, effect size 1.68) and lnRMSSD was almost certainly reduced (∼62%, effect size -5.21) from the first to the last 10-min period, indicating reduced parasympathetic and (or) enhanced sympathetic modulations. Acute exposure to extreme heat stress via sauna produced alterations in heart rate and cardiac autonomic modulations with successive postexercise heat exposures producing unclear changes over a 10-day period. The physiological benefits of intense heating via sauna on cardiac control in athletes remain to be elucidated.

Effect of Different Evasion Maneuvers on Anticipation and Visual Behavior in Elite Rugby League Players.

This study examined the anticipation and visual behavior of elite rugby league players during two different evasion maneuvers (side- and split-steps). Participants (N = 48) included elite rugby league players (n = 38) and controls (n = 10). Each participant watched videos consisting of side- and split-steps, and anticipation of movement and eye behavior were measured. No significant differences between the groups or evasion maneuvers were found. The split-step was significantly harder to predict. Elite players appeared to spend more time viewing the torso and mid-region of the body compared with the controls.

A comparison of game-play characteristics between elite youth and senior Australian National Rugby League competitions.

OBJECTIVES: To compare game-play characteristics between elite youth and senior Australian National Rugby League (NRL) competitions. DESIGN: Longitudinal observational. METHODS: The dataset consisted of 12 team performance indicators (e.g., 'all runs', 'offloads' and 'tackles') extracted from all 2016 national under 20 (U20) competition (elite youth; n=372 observations) and National Rugby League (NRL) (elite senior; n=378 observations) matches. Data was classified according to competition (Two levels: U20 and NRL) and modelled using two techniques. Firstly, non-metric multidimensional scaling resolved multivariate competition (dis)similarity, visualised using a two-dimensional ordination. Secondly, a conditional interference (CI) classification tree was grown to reveal the performance indicators most capable of explaining competition level. RESULTS: Non-metric multidimensional scaling revealed high competition dissimilarity, with U20 and NRL teams orienting distinctive positions on the first dimension of the ordination surface. Five team performance indicators were retained within the CI tree ('all runs', 'tackle breaks', 'tackles', 'missed tackles', and 'kicks'), which correctly classified 79% of the U20 observations and 93% of the NRL observations. CONCLUSIONS: Multivariate differences between elite youth and senior rugby league competitions were identified. Specifically, NRL game-play was classified by a greater number of 'all runs', and 'tackles' and a lower number of 'missed tackles' relative to the U20 competition. Given the national U20 competition is purported to assist with the development of prospective NRL players, junior coaches may consider training interventions that primarily aid the tackling capacities of players. This may subsequently assist with talent development and player progression in Australian rugby league.

Non-metric multidimensional performance indicator scaling reveals seasonal and team dissimilarity within the National Rugby League.

OBJECTIVES: Analysing the dissimilarity of seasonal and team profiles within elite sport may reveal the evolutionary dynamics of game-play, while highlighting the similarity of individual team profiles. This study analysed seasonal and team dissimilarity within the National Rugby League (NRL) between the 2005 to 2016 seasons. DESIGN: Longitudinal. METHODS: Total seasonal values for 15 performance indicators were collected for every NRL team over the analysed period (n=190 observations). Non-metric multidimensional scaling was used to reveal seasonal and team dissimilarity. RESULTS: Compared to the 2005 to 2011 seasons, the 2012 to 2016 seasons were in a state of flux, with a relative dissimilarity in the positioning of team profiles on the ordination surface. There was an abrupt change in performance indicator characteristics following the 2012 season, with the 2014 season reflecting a large increase in the total count of 'all run metres' (d=1.21; 90% CI=0.56-1.83), 'kick return metres' (d=2.99; 90% CI=2.12-3.84) and decrease in 'missed tackles' (d=-2.43; 90% CI=-3.19 to -1.64) and 'tackle breaks' (d=-2.41; 90% CI=-3.17 to -1.62). Interpretation of team ordination plots showed that certain teams evolved in (dis)similar ways over the analysed period. CONCLUSIONS: It appears that NRL match-types evolved following the 2012 season and are in a current state of flux. The modification of coaching tactics and rule changes may have contributed to these observations. Coaches could use these results when designing prospective game strategies in the NRL.

Identifying the physical and anthropometric qualities explanatory of paddling adolescents.

OBJECTIVES: This study aimed to identify the physical and/or anthropometric qualities explanatory of adolescent surf lifesavers participating in paddling activities. DESIGN: Cross-sectional observational study. METHODS: A total of 53 (14-18years) male participants were recruited and classified into two groups; paddlers (n=30; actively participating in paddling), non-paddlers (n=23; not actively participating in paddling). All participants completed a testing battery that consisted of 16 physical (isometric strength and muscular endurance) and anthropometric (height, mass, segment lengths and breadths) assessments. Binary logistic regression models and receiver operating characteristic curves were built to identify the physical and/or anthropometric qualities most explanatory of paddling status (two levels: 1=paddlers, 0=non-paddlers). RESULTS: Significant between group differences were noted for 14 of the 16 assessments (P<0.05; d=0.59-1.29). However, it was the combination of horizontal shoulder abduction isometric strength, body mass, and sitting height that provided the greatest association with paddling status (Akaike Information Criterion=47.13). This full model successfully detected 87% and 70% of the paddlers and non-paddlers, respectively, with an area under the curve of 84.2%. CONCLUSIONS: These results indicate that there are distinctive physical and anthropometric qualities that may be advantageous for prospective paddling athletes to possess. Practitioners should integrate assessments of horizontal shoulder abduction isometric strength, body mass, and sitting height, as well as their subsequent cut-off thresholds, into talent detection programs focused toward the recognition of performance potential in paddling-oriented sports.

Postactivation potentiation of dynamic conditioning contractions on rowing sprint performance.

OBJECTIVES: This study examined the post-activation potentiation effects of maximal dynamic contractions and gender on rowing sprint ability. DESIGN: Repeated measures. METHODS: Thirty-four male (n=17) and female (n=17) university students with experience in rowing took part in this study conducted across three weeks. Following familiarisation of the 10-second maximal rowing performance test on a rowing ergometer during Week 1, participants were randomly allocated to either complete a control or experimental session during Week 2 and 3. One rowing performance test was conducted during the control session whilst two rowing performance tests were conducted during the experimental session separated by 6-min. The first rowing performance test during the experimental session was used to: (1) compare measures with the control session to assess day-to-day repeatability; and (2) induce post-activation potentiation effects for the second rowing performance test. RESULTS: Based on effect size calculations, results showed moderate-large increases for average power output (+2.5%), peak power output (+1.5%) and power output during first stroke (+0.79%). CONCLUSIONS: Maximal dynamic contractions on a rowing ergometer improved subsequent rowing sprint ability in recreationally experienced male and female rowers. Accordingly, dynamic conditioning contractions on a rowing ergometer may enhance subsequent sprint-start for rowing competition success.

PLAYERS' PERCEPTIONS OF HOME ADVANTAGE IN THE AUSTRALIAN RUGBY LEAGUE COMPETITION.

This study was designed to pilot a survey to explore players' perception of home advantage in a rugby league. Twenty-seven players from one team with an identified home advantage believed a home advantage existed as a result of their home crowd (52%), family and friends' support (41%), normal travel (45%) and sleeping arrangements (37%), home weather conditions (48%), and familiarity with playing amenities (37%). However, the players were less definite about influences while playing away from home. The current sample of players identified differing influences, highlighting individual variations in perceived determinants. Individual interviews or focus groups will be required for further exploration.

The repeated bout effect of typical lower body strength training sessions on sub-maximal running performance and hormonal response.

PURPOSE: This study examined the effects of two typical strength training sessions performed 1 week apart (i.e. repeated bout effect) on sub-maximal running performance and hormonal. METHODS: Fourteen resistance-untrained men (age 24.0 ± 3.9 years; height 1.83 ± 0.11 m; body mass 77.4 ± 14.0 kg; VOpeak 48.1 ± 6.1 M kg(-1) min(-1)) undertook two bouts of high-intensity strength training sessions (i.e. six-repetition maximum). Creatine kinase (CK), delayed-onset muscle soreness (DOMS), counter-movement jump (CMJ) as well as concentrations of serum testosterone, cortisol and testosterone/cortisol ratio (T/C) were examined prior to and immediately post, 24 (T24) and 48 (T48) h post each strength training bout. Sub-maximal running performance was also conducted at T24 and T48 of each bout. RESULTS: When measures were compared between bouts at T48, the degree of elevation in CK (-58.4 ± 55.6 %) and DOMS (-31.43 ± 42.9 %) and acute reduction in CMJ measures (4.1 ± 5.4 %) were attenuated (p < 0.05) following the second bout. Cortisol was increased until T24 (p < 0.05) although there were no differences between bouts and no differences were found for testosterone and T/C ratio (p > 0.05). Sub-maximal running performance was impaired until T24, although changes were not attenuated following the second bout. CONCLUSIONS: The initial bout appeared to provide protection against a number of muscle damage indicators suggesting a greater need for recovery following the initial session of typical lower body resistance exercises in resistance-untrained men although sub-maximal running should be avoided following the first two sessions.

Wearing long pants while working outdoors in the tropics does not yield higher body temperatures.

OBJECTIVE: To compare the thermoregulatory demands of outdoor workers wearing long or knee-length pants while working in situ in a tropical environment. METHODS: Fifteen male (35.8 ± 10.5 yr) outdoor Council workers completed their daily occupational duties (construction or gardening) in trials conducted six days apart: once wearing knee-length shorts (SHORTS) and once wearing full-length pants (PANTS). Body mass and hydration were assessed prior to and following each trial with core body (T(C) ) and mean skin temperature (MST; weighted from sites: chest, arm, thigh and calf) assessed at 30-minute intervals throughout each trial. RESULTS: No significant differences between SHORTS and PANTS for T(C) , maximum T(C) , heart rate, MST or body mass changes. Skin temperature at the calf was greater for PANTS (33.8 ± 0.4°C) compared to SHORTS (32.9 ± 0.4°C; p<0.05). Hydration assessments identified 36.7% of participants commenced work hypohydrated while the average body mass lost throughout the workday was 2.5 ± 1.5%. Main effects of time were observed for heart rate and MST but no other assessed variable. CONCLUSION: The additional exposed surface area available for heat exchange when wearing shorts is insufficient to elicit differences in thermoregulatory demands of outdoor employees under the assessed conditions. IMPLICATIONS: These results suggest the use of SHORTS or PANTS can be determined by occupational duty requirements rather than risk of heat-related illness during very-light to moderate workloads completed under warm and humid environmental conditions.

Identification and reliability of pacing strategies in outrigger canoeing ergometry.

This study examined the pacing strategies utilised; and the performance reproducibility during repeated outrigger canoeing ergometer time trials. Trained female outrigger canoeists (N=11) completed four 1000m outrigger canoe ergometer time trials. There was a significant 1.5% improvement in 1000m time in trial four compared to trial one. A fast start strategy was adopted in 36 of the 44 trials (82%) followed by a deceleration during the mid stages. As trials progressed there was an increased adoption of negative pacing (fast finish) between the last two splits, indicating a learning effect of pacing strategy across repeated trials. These results demonstrate that although some performance improvement was evident between the first and fourth time trials, the 1000m outrigger ergometer time trial is a reliable test that may be used as a tool to assist with crew selection and performance monitoring. Further, on account of the variation in pacing strategy noted in the fourth trial, the authors recommend utilising one familiarisation session and one test session when assessing performance such that learning or training adaptations resulting from multiple trials do not impact on results.

Efficacy of field treatments to reduce body core temperature in hyperthermic subjects.

PURPOSE: To contrast the effects of three postcooling techniques in reducing body core temperature (Tc) in exercise-induced hyperthermic participants on the cessation of exercise. METHODS: Eleven healthy active male volunteers were cooled during a 40-min period using three different methods: ice packs to the neck, axillae, and groin (ICE); water spray and fan (FAN); and 2 L of chilled (20 degrees C) intravenous saline administered during a 20-min period (IV). Rate of decrease in Tc, cardiovascular responses, and any incidence of reported adverse effects were investigated. Trials were presented in a counterbalanced order with the volunteers' body core temperature being elevated to 40.0 degrees C on three occasions via an intermittent walk-run (2 min at 6 km x h and 4 min at 10 km x h) protocol conducted within a climate-controlled chamber (34.2 +/- 0.5 degrees C and 62.3 +/- 3.1% relative humidity). RESULTS: Rate of Tc reduction during the first 20 min of cooling was greater for FAN compared with ICE (0.09 +/- 0.02 degrees C.min vs 0.07 +/- 0.02 degrees C.min, P < 0.05), whereas IV did not differ with the other trials (0.08 +/- 0.01 degrees C.min, P > 0.05). Three participants complained of numbness or paresthesia in their arm or hand during administration of the chilled saline, although these symptoms resolved within 5 min of ceasing the infusion. CONCLUSIONS: All three cooling techniques reduced Tc and would be suitable for first aid application in a field setting during transportation to adequate medical facilities. Chilled IV saline did not produce any contraindications, providing a suitable alternative for Tc cooling.

Influence of postexercise cooling techniques on heart rate variability in men.

The reduction of core body temperature (T(C)) is vitally important in the treatment of hyperthermia; however, little is known regarding the impact of cooling treatments on the autonomic control of heart rate (HR). The aim of the present study was to examine the influence of three field-based hyperthermia treatments on the neural control of HR via heart rate variability (HRV). Following exercise-induced hyperthermia (T(C) approximately 40.0 degrees C) in a warm environment (34.2 +/- 0.5 degrees C), nine healthy, active men were treated during recovery, in a randomized order, with intravenous cold saline infusion (IV) or ice packs (ICE) or fan cooling with intermittent water spray (FAN) for 40 min. During each treatment, HR dynamics via power spectral (VLF, LF, HF), Poincare plot (SD1, SD2), approximate entropy (ApEn) and short- (alpha(1)) and long-term (alpha(2)) fractal scaling analyses were determined every 10 min. At recovery onset, HR and T(C) were similar between treatments and were significantly reduced over the 40 min recovery period. During recovery, HR and alpha(2) were significantly reduced from initial levels but were significantly greater for IV compared with ICE and FAN. In contrast, VLF, LF, HF, SD1, SD2 and ApEn increased during recovery, with all being significantly lower for IV compared with ICE and/or FAN. The present results demonstrated that IV, compared with ICE and FAN, resulted in significantly greater HR, reduced spectral and geometrical HRV, lower HR complexity and reduced long-term HR control, indicative of reduced vagal and/or increased sympathetic modulation. Specific treatments for exercise-induced hyperthermia may result in an altered sympathovagal balance that requires further examination.

Blood lactate, heart rate and rating of perceived exertion responses of elite surf lifesavers to high-performance competition.

A paucity of empirical research exists into surf lifesaving competition from which coaches and athletes may formulate training and recovery strategies. Seventeen (male=9; female=8) high-performance surf lifesavers (21.2+/-3.9 years) contested multiple rounds of team and individual events at a 2-day surf lifesaving competition. Individual events consisted of the multi-discipline ironman (IRON), paddle board (BOARD) and surf swim (SWIM). Blood lactate (BLa), rating of perceived exertion (RPE) and heart rate (HR) were determined following heats, semi-finals and final. IRON HR and RPE following semi-finals (153.0+/-21.6beatsmin(-1) and 14.4+/-1.5) and final (171.0+/-9.1beatsmin(-1) and 19.1+/-0.2) were greater than heats (141.8+/-17.2beatsmin(-1) and 12.0+/-1.9; p<0.05) and final BLa (10.5+/-2.8mmolL(-1)) was greater than heats (5.8+/-3.6mmolL(-1); p<0.05). BOARD BLa and HR were greater after the final (9.0+/-2.8mmolL(-1) and 159.0+/-19.9beatsmin(-1)) compared to heats (4.7+/-2.4mmolL(-1) and 133.0+/-17.1beatsmin(-1); p<0.05). No significant differences were identified for SWIM. RPE-HR relationships were identified for pooled IRON and BOARD results following semi-finals (0.668; p<0.05) and finals (r=0.741; p<0.05). In conclusion, high-performance surf lifesavers employ race strategies with all-out maximal exercise limited to semi-finals and finals.

Effect of exercise mode on heart rate variability during steady state exercise.

This study examined the effect of exercise mode on geometrical, and time and frequency domain measures of heart rate variability (HRV) during steady-state, moderate intensity exercise of the same HR. Seventeen healthy, active male participants volunteered for this study and completed a treadmill VO2max determination. One week later, cardiorespiratory, perceptual and HRV measures were recorded during seated rest (15 min) and consecutive bouts (15 min) of steady-state exercise at 50 and 65% of maximal HR. Exercise was performed using either upper body (arm ergometer), lower body (cycle) or whole body (treadmill) modes. Separated by 1 week and in a random order, participants undertook the same procedures with the remaining exercise modes. Cardiorespiratory, perceptual and HRV responses were determined during rest and steady-state exercise and analysed by two-way (mode vs. stage) repeated measures ANOVA and post hoc pairwise comparisons. Apart from a reduced respiratory rate during lower body exercise, whole and lower body exercise resulted in similar cardiorespiratory, perceptual and HRV responses. Compared to whole or lower body exercise, upper body exercise resulted in significantly (P < 0.05) greater measures of HRV particularly those within the very low (0-0.04 Hz) and low (0.04-0.15 Hz) frequency bands, greater rating of perceived exertion and less oxygen consumption. Upper body, moderate intensity exercise resulted in greater HRV compared to whole or lower body exercise with further studies necessary to elucidate the mechanisms and clinical implications for this greater HRV.

Thermoregulatory responses of junior lifesavers wearing protective clothing.

This study investigated the influence of protective clothing worn to prevent marine stinger envenomation on the thermoregulatory responses of pre-pubescent surf lifesavers exercising in situ under hot and humid conditions (27 degrees C, 78% relative humidity). Participants performed beach and water activities typically associated with junior surf lifesaving competition in a randomised cross-over design on two separate occasions 7 days apart: one wearing a full-length Lycra stinger suit (S) and one wearing normal swimwear (SW). Skin (T(SK)) and core (T(C)) body temperatures, skin blood flow (SKBF), heart rate (HR), body mass, thermal comfort and perceived effort were assessed pre-, mid- (following beach activities) and post-exercise (following water activities). Sweat rates were compared between S and SW. T(C) was greater following beach activities for S (37.78 degrees C+/-0.06) compared to SW (37.60 degrees C+/-0.07; p<0.05) and male participants experienced greater T(C) (37.97 degrees C+/-0.09) than their female counterparts (37.71 degrees C+/-0.07 degrees C). T(SK) following both the beach and water activities were lower than pre-exercise (p<0.05). SKBF was significantly increased for calf across time (p<0.01). Male participants experienced a higher HR for S compared to female participants (p<0.01) while the opposite applied to SW (p<0.01). There were no gender or between-condition differences for sweat rate or perceived effort. There was evidence of heat storage while stinger suits were worn during beach activities in the absence of any differences in exercise intensity or sweat rate. The results of the present study suggest that the stinger suits should be limited to water-based activities.

Pre-pubertal children and exercise in hot and humid environments: a brief review.

The ability of pre-pubertal children to regulate their body temperature under thermoneutral environments is similar to that of an adult albeit via differing routes. However, this ability is challenged when exposed to extreme environments. Thermoregulatory responses of pre-pubertal children differ from adults via adaptations that occur during growth and maturation and disadvantage children when exercising in hot and humid environments. When ambient temperatures exceed that of the skin, an influx of thermal energy from the environment increases thermal stress. When coupled with exercise, the increased thermal stress results in reduced physical performance and an increased risk of developing heat-related illness. Evidence suggesting the severity of heat-related illness is greater in pre-pubertal children than adults is inconclusive because age-related differences in thermoregulatory responses are attributed to either morphologic or functional changes. Additionally, the majority of research on pre-pubertal children exercising in the heat has been maturational or comparative studies with adults conducted in the near absence of convective cooling, complicating extrapolation to field-based environments. However, current consensus is that pre-pubertal children are disadvantaged when exercising in extreme temperatures and that care should be taken in preparing for and conducting sporting activities in hot and humid environments for pre-pubertal children. Key pointsPre-pubertal children's ability to thermoregulate when exposed to hot and humid environments is deficient compared to adults.Research into the severity of heat-related illness in pre-pubertal children is inconclusive.Discretion should be used in applying findings from indoor studies to outdoor activities due to the influence of the velocity of circulating air on thermoregulation.