Match-play movement demands of international and domestic women's rugby sevens players in an elite dual-level tournament

OBJECTIVES

To characterize and compare match-play movement demands via Global Positioning Systems (GPS) between international and domestic women's rugby sevens players performing in a novel elite dual-level tournament, with consideration to position and tournament characteristics.

DESIGN

Fifty-four rugby sevens players; twenty-one international(5 speed edges, 8 backs, 8 forwards), and thirty-three domestic(10 speed edges, 11 backs, 12 forwards) wore GPS devices during an elite dual-level tournament covering 2 seasons, with 367 full match-play data files analysed. Internationaland domestic players were distributed evenly between competing teams.

METHODS

Match-play movement demands were characterized by distance, speed, and acceleration-based indices from 5 to 10 Hz GPS devices.

RESULTS

International players recorded significantly higher high-intensity match-play movement demands compared to domestic players in distance in high and very high-speed zones (P = 0.01, P = 0.03, P = 0.01, P = 0.03), maximal acceleration (P = 0.001), maximal velocity (P < .001), speed exertion (P = 0.01),       , and acceleration load density (P = 0.03)   . Positional analysis demonstrated forwards displayed the largest significant differences between international and domestic players. . Total and relative match-play movement demands of the dual-leveltournament also showed comparable demands to previous international tournament research .

CONCLUSIONS

Results identify key points of difference in match-play movement demands between player levels in women's rugby sevens, and provides important information on the characteristics of playing positions, and of a dual-level tournament of this nature. This will improve the design and implementation of structures from domestic to international level.

Predicting repeat power ability through common field assessments: is repeat power ability a unique physical quality?

Background

The repeat power ability (RPA) assessment is used to test the ability to repeatedly produce maximal ballistic efforts with an external load. The underpinning physical qualities influencing RPA are undetermined. This study aimed to gain further insight into the physical qualities that determine RPA by analysing the association between physical qualities and an assessment of RPA.

Materials and methods

Ten well-trained male field hockey players performed an RPA assessment consisting of 20 repetitions of loaded countermovement jumps (LCMJ20), with a percent decrement score of peak power output calculated. Over a two-week period, each participant performed the YoYo Intermittent Recovery Test 2 (IRT2), a repeated speed ability assessment incorporating a 180° change of direction (RSA180), a 40-meter linear speed test (40 mST), an isometric mid-thigh pull (IMTP), a countermovement jump (CMJ), and a 3-repetition maximum half squat (HS) assessment. Pearson's correlation analysis was used to determine the strength of relationships between each assessment variable and the LCMJ20. The assessment variables with the strongest relationships within each assessment were used in a stepwise multiple linear regression analysis to determine the best predictor model of LCMJ20.

Results

RSA180percent decrement score (RSA180% had a very strong, significant relationship with LCMJ20 (r = 0.736: p < 0.05). HS relative strength (HSrel) was found to have a significant and very strong, negative relationship with LCMJ20 (r =  - 0.728: p < 0.05). Stepwise multiple linear regression analysis showed RSA180 to explain 48.4% of LCMJ20 variance (Adjusted R2 = 0.484) as the only covariate included in the model.

Conclusion

The findings indicate that RSA180 as a repeated high intensity effort (RHIE) task is strongly related to LCMJ20 and is also the best predictor of LCMJ20. This may suggest that RPA can provide practitioners with information on RHIE performance. The variance between assessment methods indicates that RPA may be a distinct physical quality, future research should assess other physical capacities to better understand the factors contributing to RPA.

The Effects of a Field-Based Priming Session on Perceptual, Physiological, and Performance Markers in Female Rugby Sevens Players

PURPOSE

This study aimed to determine the effects of a field-based priming session on perceptual, physiological, and performance responses in female rugby sevens athletes.

METHODS

Thirteen highly trained female rugby sevens players (age: 20.7 [2.0] y; height: 169.3 [4.8] cm; weight: 68.8 [7.9] kg) completed either a 20-minute field-based priming session or a control condition. Perceptual, physiological, and performance variables were collected at baseline (PRE) and 5 (POST5), 30 (POST30), and 120 minutes (POST120) postintervention. Data were analyzed using Bayesian mixed effects models.

RESULTS

The priming protocol had a larger increase in mental readiness (maximum a posteriori [MAP] = 20, 95% high-density intervals [HDI] = -4 to 42, probability of direction [PD]% = 95, % in region of practical equivalence [ROPE] = 9.7), physical readiness (MAP = 20.1, 95% HDI = -4.6 to 42.1, PD% = 93, % in ROPE = 10.6), and testosterone (MAP = 14.9, 95% HDI = 0.5 to 27.7, PD% = 98, % in ROPE = 5.6) than the control POST30. Cognitive performance decreased POST120 in the priming condition for congruent (MAP = 0.02, 95% HDI = -0.06 to 0.00, PD% = 95, % in ROPE = 6.4) and incongruent tasks (MAP = 0.00, 95% HDI = -0.07 to 0.00, PD% = 98, % in ROPE = 3.2) when compared with the control.

CONCLUSIONS

Perceptual and physiological markers improved POST30 in the priming condition. Findings indicate that perceptual and physiological responses to priming were not coupled with performance improvements. Priming was not accompanied by perceptual, physiological, or performance improvements at POST120.

Effects of 2 Different Protocols of Repeated-Sprint Training in Hypoxia in Elite Female Rugby Sevens Players During an Altitude Training Camp

OBJECTIVES

Repeated-sprint training in hypoxia (RSH) is an effective way of improving physical performance compared with similar training in normoxia. RSH efficiency relies on hypoxia severity, but also on the oxidative-glycolytic balance determined by both sprint duration and exercise-to-rest ratio. This study investigated the effect of 2 types of RSH sessions during a classic altitude camp in world-class female rugby sevens players.

METHODS

Sixteen players performed 5 RSH sessions on a cycle ergometer (simulated altitude: 3000 m above sea level [asl]) during a 3-week natural altitude camp (1850 m asl). Players were assigned to 2 different protocols with either a high (RSH1:3, sprint duration: 8-10 s; exercise-to-rest ratios: 1:2-1:3; n = 7) or a low exercise-to-rest ratio (RSH1:5, sprint duration: 5-15 s; exercise-to-rest ratios: 1:2-1:5; n = 9). Repeated-sprint performances (maximal and mean power outputs [PPOmax, and PPOmean]) were measured before and after the intervention, along with physiological responses.

RESULTS

PPOmax (962 [100] to 1020 [143] W, P = .008, Cohen d = 0.47) and PPOmean (733 [71] to 773 [91] W, P = .008, d = 0.50) increased from before to after. A significant interaction effect (P = .048, d = 0.50) was observed for PPOmean, with a larger increase observed in RSH1:3 (P = .003). No interaction effects were observed (P > .05) for the other variables.

CONCLUSION

A classic altitude camp with 5 RSH sessions superimposed on rugby-sevens-specific training led to an improved repeated-sprint performance, suggesting that RSH effects are not blunted by prolonged hypoxic exposure. Interestingly, using a higher exercise-to-rest ratio during RSH appears to be more effective than when applying a lower exercise-to-rest ratio.

Training and Competition Loads in Women's Rugby Sevens Athletes: Are There Implications for Cardiovascular Health?

National- and international-level rugby sevens athletes are exposed to high training and competition loads over the course of a competitive season. Research on load monitoring and body-system responses is widespread; however, the primary focus has been on optimizing performance rather than investigating or improving cardiovascular health. There is a degree of cardiovascular remodeling, as well as local and systemic inflammation, in response to excessive exercise. These responses are moderated by many factors including previous exercise exposure, current exercise intensity and duration, age, race, and gender, as well as sport-specific physiology. For these reasons, high-performing female rugby sevens athletes may have a unique cardiovascular risk profile different from males and other rugby codes. This review aimed to characterize the training and competition loads, as well as the anthropometric and physiological profiles, of female rugby sevens athletes; discuss the potential impacts these may have on the cardiovascular system; and provide recommendations on future research regarding the relationship between rugby sevens training and competition loads and cardiovascular health. Movement demands, competition formatting, and training routines could all contribute to adverse cardiovascular adaptations. Anthropometric data and physiological characteristics may also increase the risk of cardiovascular disease. Future research needs to adopt measures of cardiovascular health to obtain a greater understanding of cardiovascular profiles and risk factors in female rugby sevens athletes.

New Zealand Youth Rugby Sevens: A Comparative Match Demands Study

Rugby sevens has established itself on the world stage since its inclusion in the 2016 Olympics. Participation among New Zealand (NZ) youth has surged. Sevens games have specific high demands, but little is known about these competitive demands in regards to youth. Two NZ male youth squads (U15, n = 13; U19, n = 14) were monitored during a national sevens tournament. Microsensor technology captured heart rate (HR) and kinematic performance. The rating of perceived exertion (RPE) was collected for U15 matches only. U19 and U15 players ran 108 ± 11 and 116 ± 13 m·min^-1 at an average speed (V_AVG) of 6.5 ± 0.6 and 6.9 ± 0.8 km·h^-1. Peak speeds (V_PEAK) reached 33.7 km·h^-1, and high-intensity running distance (HIRD) averaged 252 ± 102 m. U15 (44.3 ± 9.2 game^-1) and U19 (39.4 ± 6.1 game^-1) showed different sprint rates. U15 covered more moderate-velocity distance (20-80% V_MAX) and less low-velocity distance (<20% V_MAX). RPE was 13 ± 1 (U15). An average HR of 90.0 ± 3.9% HR_MAX was recorded. Upwards of 57% of game time was played at >95% HR_MAX. Youth sevens competition is specifically demanding. U15 can experience greater loads than older peers in rugby. Coaches can use this information to optimize players' physical development.

The Validity, Reliability, and Agreement of Global Positioning System Units-Can We Compare Research and Applied Data?

ABSTRACT

Brosnan, RJ, Watson, G, Stuart, W, Twentyman, C, Kitic, CM, and Schmidt, M. The validity, reliability, and agreement of GPS units-Can we compare research and applied data? J Strength Cond Res 36(12): 3330-3338, 2022-This study's aim was to investigate the validity, within-brand interunit reliability, and between-brand agreement of movement indicators from 3 commonly used global positioning system (GPS) units used in applied and research settings. Forty-two units (GPSports EVO; 10 Hz, n = 13: GPSports HPU; 5 Hz, n = 14: and Catapult S5; 10 Hz, n = 15) were investigated across 3 experiments: a 40-m linear track with all units pushed on a trolley, a sport simulation circuit with all units pulled on a sled, and a similar circuit with 3 models of units placed in a modified GPS vest worn by an athlete between the scapulae. Distance, speed, and acceleration indices were obtained and analyzed with the level of significance set ( ρ < 0.05). The results demonstrated good to moderate (% mean difference; 0-6.5%) validity with criterion and good (coefficient of variation [CV] ± 90% confidence interval [CI]: 0-3.9%) interunit reliability for distance and speed in units. Ten hertz units demonstrated good to moderate (CV ± 90% CI: 0.21-5.58%) interunit reliability in all acceleration and deceleration measures, with 5 Hz units having good to poor (CV ± 90% CI: 4.54-12.78%) results. Agreement ranged from good to moderate (% mean difference; 0.01-7.8%) for distance, speed, and absolute acceleration/deceleration. Agreement ranged from good to poor (% mean difference; 2.21-32.74%) in average acceleration. The GPS units investigated can be compared within and between applied and research settings for distance and speed. However, caution is warranted in acceleration indices. This highlights the importance of testing other commonly used GPS models and brands.

Effects of plyometric training on softer vs. Harder surfaces on jump-related performance in rugby sevens players

This study aimed to compare jump-related performance after plyometric training on harder vs. softer surfaces in rugby sevens players. Fourteen players were randomly assigned to the harder surface group (H-G, n = 7) and softer surface group (S-G, n = 7). Three times per week, in the morning, the players performed plyometric training on different surfaces and strength training. Before and after the 4-week intervention period, squat jump (SJ), countermovement jump (CMJ), and CMJ with arms (CMJA) tests were performed to measure vertical jump displacement (d), rate of force development (r), and power (p). The main results indicated a significant improvement in S-G for CMJd (∆% = +8.2%; p = 0.029; ES = 0.59) and for CMJAp (∆% = +8.7%; p = 0.035; ES = 0.44). These improvements were significant compared to H-G for CMJAd (F_1,12 = 8.50; p = 0.013; ηp2 = 0.41; ES = 0.83) and CMJAp (F_1,12 = 7.69; p = 0.017; ηp2 = 0.39; ES = 0.79). This study reveals that performance related to the counter movement jump with arms on softer surfaces after 4-week plyometric training improved vertical jump displacement and lower body power in rugby sevens players.

Assessing the Relationship Between External and Internal Match Loads in Elite Women's Rugby Sevens

PURPOSE

To assess the relationship between external and internal load during official women's rugby seven matches.

METHODS

Six backs (age = 24.2 [3.2] y; height = 161.5 [7.3] cm; body mass = 59.5 [5.0] kg; playing experience = 5.3 [1.5] y) and 8 forwards (age = 22.4 [2.7] y; height = 167.0 [4.8] cm; body mass = 70.6 [5.6] kg; playing experience = 5.0 [1.5] y) belonging to the women's rugby seven Brazilian national team were monitored across 3 international tournaments during the 2019-20 season, with 2 players excluded from the analysis since they did not participate in any investigated match. Total distance (TD), distance during high-intensity running 18.1 to 20.0 km·h-1 and >20 km·h-1 (sprinting), number of accelerations >1.8 m·s-2 (ACC), and of decelerations <1.8 m·s-2 were used as match load volume measures, while their relative values (TD per minute, high-intensity running per minute, sprinting per minute, ACC per minute, and decelerations per minute) were used as external load match intensity measures. Internal load intensity and volume were assessed using the session rating of perceived exertion (sRPE) and its value multiplied by match duration (sRPE-ML), respectively. Spearman correlations and linear mixed models were used to assess the relationships between internal and external load measures.

RESULTS

A very large relationship (ρ = .830, P < .001) was found between sRPE-ML and TD, with linear mixed models showing that TD statistically affected sRPE-ML (P < .001). Linear mixed models analysis showed that ACC per minute was also affecting the sRPE-ML (P = .017), while sprinting (P = .007) and ACC per minute (P = .005) were the only 2 measures statistically affecting sRPE. However, weak relationships (trivial to large) were found for these and all other measures.

CONCLUSIONS

These results highlight that TD is the main external load measure able to anticipate the internal load responses measured via sRPE-ML in elite women's rugby sevens.

Repeated sprint training under hypoxia improves aerobic performance and repeated sprint ability by enhancing muscle deoxygenation and markers of angiogenesis in rugby sevens

OBJECTIVE

To evaluate the effects of repeated sprint (RS) training in hypoxia on aerobic performance, repeated sprint ability (RSA), and muscle oxygenation in Rugby Sevens.

METHODS

Fourteen Rugby Sevens players were randomly allocated into hypoxic (RSH, F_IO₂ = 14.5%, n = 7) or normoxic (RSN, F_IO₂ = 20.9%, n = 7) groups. Both groups underwent RS training consisting of 3 sets of 6-s × 10 sprints at 140% of velocity at peak oxygen uptake ([Formula: see text]) on a motorized treadmill, 3 days/week for 6 weeks in addition to usual training. Hematological variables, hypoxia-inducible factor-1 alpha (HIF-1α), and vascular endothelial growth factor (VEGF) concentrations were measured. Aerobic performance, RSA, and muscle oxygenation during the running-based anaerobic sprint (RAS) test were analyzed.

RESULTS

RSH caused no changes in hemoglobin concentration and hematocrit but significant improvements in [Formula: see text] (7.5%, p = 0.03, ES = 1.07), time to exhaustion (17.6%, p = 0.05, ES = 0.92), and fatigue index (FI, - 12.3%, p = 0.01, ES = 1.39) during the RSA test compared to baseline but not RSN. While ∆deoxygenated hemoglobin was significantly increased both after RSH and RSN (p < 0.05), ∆tissue saturation index (- 56.1%, p = 0.01, ES = 1.35) and ∆oxygenated hemoglobin (- 54.7%, p = 0.04, ES = 0.97) were significantly decreased after RSH. These changes were concomitant with increased levels of HIF-1α and VEGF in serum after RSH with a strong negative correlation between ∆FI and ∆deoxygenated hemoglobin after RSH (r = - 0.81, p = 0.03).

CONCLUSION

There was minimal benefit from adding RSH to standard Rugby Sevens training, in eliciting improvements in aerobic performance and resistance to fatigue, possibly by enhanced muscle deoxygenation and increased serum HIF-1α and VEGF concentrations.

Evaluation of a randomized nutrition intervention combining nutrition education and cooking workshops on dietary intakes and psychosocial determinants of performance in university football athletes

Although nutrition influences performance, many athletes, including football players, do not meet nutritional requirements for their sport. The objective of this study was to determine the impact of a nutrition intervention combining nutrition education and cooking workshops on nutrition knowledge, intention, and perceived behavioral control in the preparation of healthy meals, dietary intakes, and diet quality in male university football players. Athletes ( n = 23; age: 22 ± 1 year) were randomly assigned to an intervention (2 h/week) ( n = 13) or control group ( n = 10) over three weeks. Questionnaires were completed before (pre), immediately after (post 1), and two months after the intervention (post 2). Dietary intakes and diet quality were evaluated from three web-based 24-h dietary recalls per visit. Mixed linear models for repeated measures with Tukey’s post hoc test were performed to determine the effects of the intervention on all outcomes. There was a group by time interaction for nutrition knowledge ( p = 0.002) that was higher immediately after and two months after the intervention compared to the control group. No differences on other outcomes were observed. Combining nutrition education and cooking workshops improved nutrition knowledge, but did not affect intention and perceived behavioral control in the preparation of healthy meals, dietary intakes, and diet quality in male university football athletes.

Influence of Congested Match Schedules, Pre-Match Well-Being and Level of Opponents on Match Loads during World Rugby Women's Sevens Series

This study aimed at assessing (1) the effect of congested match schedules on match loads and well-being as well as (2) pre-match well-being and level of opponents on match loads in elite women’s rugby sevens. Eleven players of the Brazilian women’s rugby sevens national team were investigated across three 2019-20 HSVC World Rugby Women’s Seven Series tournaments to assess: (1) within-tournament match-to-match changes in various external and internal match load measures; (2) daily changes in players’ well-being collected before the commencement of a tournament (day one) and during or post-tournament (day two to day four); and (3) the effect of pre-match well-being and level of opponents (high vs. low level) on match loads. Results revealed no between-match significant differences (p > 0.05) in most of the investigated match load measures. A congested match schedule negatively affected perceived fatigue (p < 0.001), muscle soreness (p = 0.004) and overall wellness (p < 0.001), with post hoc analyses showing decreased values on day four compared to previous days (small-to-moderate effect sizes). Finally, pre-match well-being and level of opponents did not affect match loads (p > 0.05). These results highlighted the necessity to embrace a multidimensional approach when adopting monitoring systems in elite women’s rugby sevens during tournaments and to consider various contextual factors possibly affecting match loads, besides those investigated.

Monitoring external load in elite male handball players depending on playing positions

Monitoring workload is critical for elite training and competition, as well as preventing potential sports injuries. The assessment of external load in team sports has been provided with new technologies that help coaches to individualize training and optimize their team's playing system. In this study we characterized the physical demands of an elite handball team during an entire sports season. Novel data are reported for each playing position of this highly strenuous body-contact team sport. Sixteen world top players (5 wings, 2 centre backs, 6 backs, 3 line players) were equipped with a local positioning system (WIMU PRO) during fourteen official Spanish first league matches. Playing time, total distance covered at different running speeds, and acceleration variables were monitored. During a handball match, wings cover the greater distance by high-speed running (> 5.0 m·s-1): 410.3 ± 193.2 m, and by sprint (> 6.7 m·s-1): 98.0 ± 75.4 m. Centre backs perform the following playing position that supports the highest speed intensities during the matches: high-speed running: 243.2 ± 130.2 m; sprint: 62.0 ± 54.2 m. Centre backs also register the largest number of high-intensity decelerations (n = 142.7 ± 59.5) compared to wings (n = 112.9 ± 56.0), backs (n = 105.2 ± 49.2) and line players: 99.6 ± 28.9). This study provides helpful information for professional coaches and their technical staff to optimize training load and individualize the physical demands of their elite male handball players depending on each playing position.

Differences in physical performance between Olympic and non-Olympic female rugby sevens players

BACKGROUND

This study compared the physical performance of National female rugby sevens players selected or not selected to form the Brazilian National Olympic team.

METHODS

Thirty women rugby sevens players from the Brazilian National team (15 Olympic and 15 non-Olympic athletes) participated in this study. Tests were performed on consecutive days, in the following order: day 1) standing long jump (SLJ); squat and countermovement jumps (SJ and CMJ); and one-repetition maximum test in the bench-press, prone-row, and parallel squat exercises; day 2) 40-m linear sprint; Pro-agility and L-drill change of direction tests; and Yo-Yo intermittent recovery test level 1 (IR1). The differences between groups in all variables examined were analyzed using the independent t test and effect sizes (ES).

RESULTS

Greater jump performances were noticed for the Olympic players in all jump tests compared to the non-Olympics (ES=0.95, ES=1.05, and ES=0.93, for SLJ, SJ, and CMJ, respectively; P<0.05). Olympics revealed shorter sprint times than non-Olympics in 40-m distance (ES=0.88; P<0.05). Higher one-repetition maximum in the bench-press and Yo-Yo IR1 distance were also observed for the Olympics in comparison to non-Olympic players (ES=0.65 and 0.93, respectively; P<0.05).

CONCLUSIONS

Lower-body power, upper-body strength, maximal sprint velocity and aerobic fitness were found to be important for distinguishing between Olympic and non-Olympic female rugby sevens players. Coaches and practitioners should prioritize the development of these physical qualities in these team-sport athletes.

The Effect of High Volume Power Training on Repeated High-Intensity Performance and the Assessment of Repeat Power Ability: A Systematic Review

BACKGROUND

High volume power training (HVPT) involves high volumes of high-velocity resistance training, with the aim to improve repeated high-intensity efforts (RHIEs). Repeat power ability (RPA) is the ability to repeatedly produce maximal or near maximal efforts. Assessments of RPA using external loading may determine the ability to perform repeat RHIEs typical of many sports and, therefore, provide useful information on the effectiveness of training.

OBJECTIVES

(1) Identify the different HVPT protocols; (2) examine the acute responses and chronic adaptations to different HVPT protocols; (3) identify different lower body RPA assessment protocols and highlight similarities, differences and potential limitations between each protocol, and; (4) describe the reliability and validity of RPA assessments.

METHODS

An electronic search was performed using SPORTDiscus, PubMed, CINAHL and Embase for studies utilising HVPT protocols and assessments of RPA. Eligible studies included peer-reviewed journal articles published in English.

RESULTS

Twenty studies met the inclusion criteria of the final review. Of the eight longitudinal studies, three were rated as fair and five were rated as poor methodological quality, respectively. In contrast, all 12 cross-sectional studies were considered to have a low risk of bias. Preliminary evidence suggests that HVPT can enhance RHIE, RPA, anaerobic capacity, anaerobic power and aerobic performance. HVPT generally consists of 2-3 sessions per week, utilising loads of 30-40% 1 repetition maximum (RM), for 3-5 sets of 10-20 repetitions, with inter-set rest periods of 2-3 min. RPA assessments can be valid and reliable and may provide useful information on an athlete's ability to perform RHIE and the success of HVPT programmes.

CONCLUSIONS

HVPT can be used to improve a number of physical qualities including RPA and RHIE; while a variety of RPA assessments provide valid and reliable information regarding the athlete's ability to perform RHIEs. Considering the heterogeneity in the HVPT protocols currently used and the relatively low volume and quality of longitudinal publications in this area, further studies are needed to identify the effects of a variety of HVPT methods on RPA, RHIE and other performance outcomes and to identify the most valid and reliable RPA outcomes to use in such studies.

Changes in Core Temperature During an Elite Female Rugby Sevens Tournament

PURPOSE

To characterize player core temperature (Tc) across a World Rugby Women's Sevens Series tournament day (WRWSS) and determine the efficacy of commonly employed cold-water-immersion (CWI) protocols.

METHODS

Tc was measured in 12 elite female rugby sevens athletes across 3 games (G1-3) from day 1 of the Sydney WRWSS tournament. Symptoms of exertional heat illness, perceptual scales, CWI details, playing minutes, external-load data (measured by global positioning systems), and wet-bulb globe temperature (range 18.5°C-20.1°C) were also collected. Linear mixed models and magnitude-based inferences were used to assess differences in Tc between periods (G1-3 and warm-ups [WU]).

RESULTS

Average Tc was "very likely" lower (effect size; ±90% confidence limit -0.33; ±0.18) in G1 than in G2. Peak Tc was "very likely" (0.71; ±0.28) associated with increased playing time. CWI did not remove the accumulated Tc due to WU and match-play activity (∼1°C-2°C rise in Tc still present compared with Tc at WU onset for players ≥6-min match play).

CONCLUSIONS

Elite WRWSS athletes experienced high Tc during WU (Tc peak 37.9-39.0°C) and matches (Tc peak 37.9-39.8°C), a magnitude known to reduce intermittent high-intensity physical performance (≥39°C). The CWI protocol resulted in players (≥6-min match play) with ∼1°C to 2°C raised Tc compared with Tc at WU onset.

High-Intensity Acceleration and Deceleration Demands in Elite Team Sports Competitive Match Play: A Systematic Review and Meta-Analysis of Observational Studies

BACKGROUND

The external movement loads imposed on players during competitive team sports are commonly measured using global positioning system devices. Information gleaned from analyses is employed to calibrate physical conditioning and injury prevention strategies with the external loads imposed during match play. Intense accelerations and decelerations are considered particularly important indicators of external load. However, to date, no prior meta-analysis has compared high and very high intensity acceleration and deceleration demands in elite team sports during competitive match play.

OBJECTIVE

The objective of this systematic review and meta-analysis was to quantify and compare high and very high intensity acceleration vs. deceleration demands occurring during competitive match play in elite team sport contexts.

METHODS

A systematic review of four electronic databases (CINAHL, MEDLINE, SPORTDiscus, Web of Science) was conducted to identify peer-reviewed articles published between January 2010 and April 2018 that had reported higher intensity (> 2.5 m·s-2) accelerations and decelerations concurrently in elite team sports competitive match play. A Boolean search phrase was developed using key words synonymous to team sports (population), acceleration and deceleration (comparators) and match play (outcome). Articles only eligible for meta-analysis were those that reported either or both high (> 2.5 m·s-2) and very high (> 3.5 m·s-2) intensity accelerations and decelerations concurrently using global positioning system devices (sampling rate: ≥ 5 Hz) during elite able-bodied (mean age: ≥ 18 years) team sports competitive match play (match time: ≥ 75%). Separate inverse random-effects meta-analyses were conducted to compare: (1) standardised mean differences (SMDs) in the frequency of high and very high intensity accelerations and decelerations occurring during match play, and (2) SMDs of temporal changes in high and very high intensity accelerations and decelerations across first and second half periods of match play. Using recent guidelines recommended for the collection, processing and reporting of global positioning system data, a checklist was produced to help inform a judgement about the methodological limitations (risk of detection bias) aligned to 'data collection', 'data processing' and 'normative profile' for each eligible study. For each study, each outcome was rated as either 'low', 'unclear' or 'high' risk of bias.

RESULTS

A total of 19 studies met the eligibility criteria, comprising seven team sports including American Football (n = 1), Australian Football (n = 2), hockey (n = 1), rugby league (n = 4), rugby sevens (n = 3), rugby union (n = 2) and soccer (n = 6) with a total of 469 male participants (mean age: 18-29 years). Analysis showed only American Football reported a greater frequency of high (SMD = 1.26; 95% confidence interval [CI] 1.06-1.43) and very high (SMD = 0.19; 95% CI - 0.42 to 0.80) intensity accelerations compared to decelerations. All other sports had a greater frequency of high and very high intensity decelerations compared to accelerations, with soccer demonstrating the greatest difference for both the high (SMD = - 1.74; 95% CI - 1.28 to - 2.21) and very high (SMD = - 3.19; 95% CI - 2.05 to - 4.33) intensity categories. When examining the temporal changes from the first to the second half periods of match play, there was a small decrease in both the frequency of high and very high intensity accelerations (SMD = 0.50 and 0.49, respectively) and decelerations (SMD = 0.42 and 0.46, respectively). The greatest risk of bias (40% 'high' risk of bias) observed across studies was in the 'data collection' procedures. The lowest risk of bias (35% 'low' risk of bias) was found in the development of a 'normative profile'.

CONCLUSIONS

To ensure that elite players are optimally prepared for the high-intensity accelerations and decelerations imposed during competitive match play, it is imperative that players are exposed to comparable demands under controlled training conditions. The results of this meta-analysis, accordingly, can inform practical training designs. Finally, guidelines and recommendations for conducting future research, using global positioning system devices, are suggested.

Technical determinants of tackle and ruck performance in International Rugby Sevens

Abstract Rugby Sevens ('Sevens') is one of the fastest growing sports in the world. This growth was marked by the inclusion of the sport in the Olympic Games in 2016. The most frequently occurring contact events in Sevens are the tackle and ruck. Performing specific techniques during these contact events can reduce the risk of injury and increase the likelihood of success. Therefore, the purpose of this study was to identify the technical determinants associated with tackle and ruck performance outcomes in Sevens. A total of 4799 tackles and 1405 rucks from the 2014/2015 HSBC Sevens World Series were coded for contact, post-contact, ruck, match contextual variables and outcomes. Relative risk ratio (RR), the ratio of the probability of an outcome occurring when a variable was observed, was determined using multinomial logistic regression. A moderate ball-carrier leg drive reduced the probability of losing possession by 25% (RR 0.75, 95% CI, 0.58-0.97, p < .05). Conversely, ball-carriers had a 53% higher likelihood of losing possession when the tackler executed a moderate leg drive (RR 1.53, 95% CI, 1.09-2.14, p ≤ .05). Maintaining possession at the ruck was more likely to occur when committing one attacker compared to two (RR 0.31, 95% CI, 0.19-0.49, p < .001). Active ball-carrier placement also increased the likelihood of maintaining possession at the ruck (RR 14.67, 95% CI, 9.55-22.56, p < .001). Sevens coaches and trainers can now positively design evidence-based technical training programmes and emphasise specific tackle techniques in training using data from Sevens video analysis. Also, given that this is the first study to relate tackle technical determinants to an outcome (i.e. the first 'how' study) in Sevens, this work provides the foundation for similar Sevens video analysis studies in the future.

Limiting the Rise in Core Temperature During a Rugby Sevens Warm-Up With an Ice Vest

PURPOSE

To determine how a cooling vest worn during a warm-up could influence selected performance (countermovement jump [CMJ]), physical (global positioning system [GPS] metrics), and psychophysiological (body temperature and perceptual) variables.

METHODS

In a randomized, crossover design, 12 elite male World Rugby Sevens Series athletes completed an outdoor (wet bulb globe temperature 23-27°C) match-specific externally valid 30-min warm-up wearing a phase-change cooling vest (VEST) and without (CONTROL), on separate occasions 7 d apart. CMJ was assessed before and after the warm-up, with GPS indices and heart rate monitored during the warm-ups, while core temperature (Tc; ingestible telemetric pill; n = 6) was recorded throughout the experimental period. Measures of thermal sensation (TS) and thermal comfort (TC) was obtained pre-warm-up and post-warm-up, with rating of perceived exertion (RPE) taken post-warm-ups.

RESULTS

Athletes in VEST had a lower ΔTc (mean [SD]: VEST = 1.3°C [0.1°C]; CONTROL = 2.0°C [0.2°C]) from pre-warm-up to post-warm-up (effect size; ±90% confidence limit: -1.54; ±0.62) and Tc peak (mean [SD]: VEST = 37.8°C [0.3°C]; CONTROL = 38.5°C [0.3°C]) at the end of the warm-up (-1.59; ±0.64) compared with CONTROL. Athletes in VEST demonstrated a decrease in ΔTS (-1.59; ±0.72) and ΔTC (-1.63; ±0.73) pre-warm-up to post-warm-up, with a lower RPE post-warm-up (-1.01; ±0.46) than CONTROL. Changes in CMJ and GPS indices were trivial between conditions (effect size < 0.2).

CONCLUSIONS

Wearing the vest prior to and during a warm-up can elicit favorable alterations in physiological (Tc) and perceptual (TS, TC, and RPE) warm-up responses, without compromising the utilized warm-up characteristics or physical-performance measures.

Preconditioning Strategy in Rugby-7s Players: Beneficial or Detrimental?

PURPOSE

Preconditioning strategies are considered as opportunities to optimize performance on competition day. While investigations conducted in rugby players on the effects of a morning preconditioning session already exist, additional work is warranted. The aim of this study was to monitor changes in physical and psychophysiological indicators among international Rugby-7s players following a priming exercise.

METHODS

In a randomized crossover-design, fourteen under-18 international Rugby-7s players completed, at 8:00am, a preconditioning session consisting of a warm-up followed by small-sided games, accelerations and 2 x 50-m maximal sprints (Experimental) or no pre-loading session (Control). Following a 2-hour break, the players performed a set of six 30-m sprints and a Rugby-7s match. Recovery-stress state and salivary stress-markers levels were assessed before the preloading session (Pre), immediately after (Post-1), before the testing session (Post-2) and after (Post-3).

RESULTS

Experimental-Control differences in performance across a repeated sprint test consisting of six 30-m sprints were very likely trivial (+0.2 ±0.7%, 3/97/1%). During the match, the total distance covered and the frequency of decelerations were possibly lower (small) in Experimental compared to Control. Differences observed in the other parameters were unclear or possibly trivial. At Post-2, the perceived recovery-stress state was improved (small difference) in Experimental compared with Control. No difference in salivary cortisol response was observed while the preconditioning session induced a higher stimulation of salivary testosterone and alpha-amylase.

CONCLUSIONS

The players' ability to repeat sprints and physical activity in match-play did not improve but their psychophysiological state was positively affected after the present pre-conditioning session.

Training Periodization Over an Elite Rugby Sevens Season: From Theory to Practice

PURPOSE

To describe the training periodization in rugby sevens players competing in the World Rugby Sevens Series during a non-Olympic season.

METHODS

Workload data were collected over a 33-wk period in 12 male players participating in a full competitive season. Workload was quantified using session rating of perceived exertion and global positioning system-derived data during training and competition. Self-reported well-being was assessed using a questionnaire. Each variable was analyzed weekly and through 5 mesocycles (preseason, in-season 1-4), each of which ended with competition blocks.

RESULTS

The perceived load decreased throughout the season for the full squad (-68% [26%] between preseason and final competitive block, large effect) and when unavailable players were removed from the analysis (-38% [42%], moderate). Weekly perceived load was highly variable, with a typical periodization in 4 phases during each mesocycle (regeneration, training overload, taper, and competition). During the preseason, the workload was higher during the overload training phase than during the competitive period (range: +23% to +59%, large to very large, for the distance covered above individual maximal aerobic speed and the number of accelerations). This observation no longer persisted during the season. The well-being score decreased almost certainly from in-season 3 (moderate).

CONCLUSIONS

These results highlighted the apparent difficulty in maintaining high-load training periods throughout the season in players engaged on the World Rugby Sevens Series despite ∼4-7 training weeks separating each competitive block. This observation was likely explained by the difficulties inherent to the World Rugby Sevens Series (risk of contact injury, calendar, and multiple long-haul travel episodes) and potentially by limited squad-rotation policies.

Can we use GPS for assessing sprinting performance in rugby sevens? A concurrent validity and between-device reliability study

The purpose of this study was to (1) provide data on maximal sprinting speed (MSS) and maximal acceleration (Amax) in elite rugby sevens players measured with GPS devices, (2) test the concurrent validity of the signal derived from a radar device and a commercially available 16 Hz GPS device, and (2) assess the between-device reliability of MSS and Amax of the same GPS. Fifteen elite rugby sevens players (90 ± 12 kg; 181 ± 8 cm; 26 ± 5 y) participated in the maximal sprinting test. A subset of five players participated in the concurrent validity and between-devices reliability study. A concurrent validity protocol compared the GPS units and a radar device (Stalker ATS II). The between-device reliability of the GPS signal during maximal sprint running was also assessed using 6 V2 GPS units (Sensorevery-where, Digital Simulation, Paris, France) attached to a custom-made steel sled and pushed by the five athletes who performed a combined total of 15 linear 40m sprints. CV ranged from 0.5, ±0.1 % for MSS and smoothed MSS to 6.4, ±1.1 % for Amax. TEM was trivial for MSS and smoothed MSS (0.09, ±0.01) and small for Amax and smoothed Amax (0.54, ±0.09 and 0.39, ±0.06 respectively). Mean bias ranged from -1.6, ±1.0 % to -3.0, ±1.1 % for smoothed MSS and MSS respectively. TEE were small (2.0, ±0.55 to 1.6, ±0.4 %, for MSS and smoothed MSS respectively. The main results indicate that the GPS units were highly reliable for assessing MSS and provided acceptable signal to noise ratio for measuring Amax, especially when a smoothing 0.5-s moving average is used. This 16 Hz GPS device provides sport scientists and coaches with an accurate and reliable means to monitor running performance in elite rugby sevens.

Alterations in core temperature during World Rugby Sevens Series tournaments in temperate and warm environments †

PURPOSE

To characterize player core temperature (Tc) across two separate World Rugby Sevens Series (WRSS) tournaments in temperate and warm environments.

METHODS

Tc was collected in seventeen playing members of one men's team competing at the Singapore (n = 12) and London (n = 11) WRSS tournaments. Exertional heat illness (EHI) symptoms, cooling strategy use, playing minutes and wet blub globe temperature (WBGT) were also collected. Linear mixed models and magnitude-based inferences assessed differences in Tc between all periods within-and between tournaments and were also used to assess the effect of WBGT and playing minutes on Tc.

RESULTS

Several players experienced Tc in excess of 38°C during warm-ups and 39°C during games. The highest mean Tc values were observed in the final game on all days and in Singapore Day Two, there were substantial game-on-game increases in mean Tc. These Tc responses were associated with playing minutes (effect size; ±90% CL = 0.38; ±0.20), although the effect of WBGT was trivial and unclear. Further, there were no differences in Tc between the two tournaments in the different environments. Despite high individual peak Tc values (Singapore 39.9°C; London 39.6°C); no signs/symptoms of EHI were reported, voluntary post-game cooling usage was minimal, and pre- and mid-cooling strategies were not implemented.

CONCLUSIONS

During WRSS matches, peak Tc values approached thresholds associated with EHI (>40°C) and exceeded those demonstrated to reduce repeated sprint performance (>39°C). Practitioners may consider the use of compatible cooling and heat acclimation strategies to minimize Tc increase and maximize player preparedness and recovery.

Maximum Movement Workloads and High-Intensity Workload Demands by Position in NCAA Division I Collegiate Football

Sanders, GJ, Roll, B, Peacock, CA, and Kollock, RO. Maximum movement workloads and high-intensity workload demands by position in NCAA Division I collegiate football. J Strength Cond Res 34(7): 1974-1981, 2020-The purpose of the study was to quantify the average and maximum (i.e., peak) movement workloads, and the percent of those workloads performed at high intensity by NCAA Division I football athletes during competitive games. Using global positioning system devices (Catapult Sports), low, moderate, and high and total multidirectional movement workloads were quantified by each position. Strategically achieving maximal workloads may improve both conditioning and rehabilitation protocols for athletes as they prepare for competition or return to play after an injury. A total of 40 football athletes were included in the analysis. For the data to be included, athletes were required to participate in ≥75% of the offensive or defensive snaps for any given game. There was a total of 286 data downloads from 13 different games for 8 different football positions. Data were calculated and compared by offensive and defensive position to establish the mean, SD, and maximum workloads during competitive games. The percent high-intensity workload profile was established to assess the total number and percent of high-intensity movement workloads by position. The profile was calculated by dividing a position's maximal high-intensity movement workload by the total (e.g., sum of maximal low, moderate, and high-intensity movements) movement workload. One-way analysis of variances revealed that there was a main effect of football position for total movement workloads and the percent of workloads performed at high intensities (p ≤ 0.025 for all). Maximal high-intensity workloads were 1.6-4.3 times greater than average high-intensity workloads, and the percent of total workloads performed at high intensities varied greatly by position. Strategically training for and using maximal movement workloads can help ensure that athletes are achieving workloads that are similar to the greatest demands of a competitive game.