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Redman, KJ, Wade, L, Whitley, R, Connick, MJ, Kelly, VG, and Beckman, EM. The relationship between match tackle outcomes and muscular strength and power in professional rugby league. J Strength Cond Res 36(10): 2853–2861, 2022—Tackling is a fundamental skill in collision sports, such as rugby league. Match success is largely dependent on a player's ability to complete tackles and tolerate physical collisions. High levels of strength and power are key physical qualities necessary for effective tackling because players are required to generate large forces while pushing and pulling their opponents. The aim of this study was to examine the relationship between tackle outcomes and strength and power qualities in professional rugby league. Fourteen rugby league players participated in this study. Maximal strength was assessed through 1 repetition maximum on the back squat, bench press, and bench pull. Lower-body vertical and horizontal powers were evaluated using a countermovement jump and standing broad jump (SBJ), respectively. Upper-body power was assessed on a plyometric push-up (PPU). Postmatch analysis of 5 National Rugby League matches was conducted to examine tackling outcomes. A series of Spearman's rank-order correlations were used to assess the relationship among match tackle outcomes and strength and power variables. Significant associations were observed between play-the-ball speed and SBJ peak power (rs = −0.74, p = 0.003), postcontact metres and PPU peak power (rs = 0.77, p = 0.002), losing the play-the-ball contest in defence with SBJ distance (rs = 0.70, p = 0.006), and ineffective tackles with PPU concentric impulse (rs = 0.70, p = 0.007). These results suggest the development and maintenance of full-body power to enhance the likelihood of positive tackle outcomes during professional rugby league match-play. [ABSTRACT FROM AUTHOR]

Crang, ZL, Hewitt, A, Scott, TJ, Kelly, VG, and Johnston, RD. Relationship between pre-season training load, match performance and match activities in professional rugby league. J Strength Cond Res 36(9): 2581–2588, 2022—This study aimed to establish the relationship between preseason training loads, technical match performance, and physical match activities in rugby league. Twenty-two professional rugby league players (age: 24.7 ± 4.0 years; height: 184.3 ± 4.7 cm; and body mass: 101.1 ± 9.9 kg) participated in the study. Training loads and physical match activities were monitored using global positioning systems. Total distance (m), high-speed running distance (VT1IFT; distance covered above estimated first ventilatory threshold [≥68% of 30–15 intermittent fitness test]) and total session rating of perceived exertion from all field-based (32.5 ± 8.5) and gym-based sessions (39.1 ± 12.5) were used to quantify preseason loads. Physical match activities were measured as total and high-speed running distance relative to individual playing time, whereas technical match activities and performance scores were used to evaluate individual match performance. To examine the relationship between physical match activities, technical performance, and preseason load, Pearson's correlation coefficients were quantified for each in-season game before performing a Fisher Z Transformation. Preseason high-speed running distance was positively associated with high-speed match activities (r = 0.34–0.51), whereas negatively associated with technical performance scores (r = −0.51 to −0.35) and hit up m·min−1 of match-play (r = −0.30 to −0.17). It seems high speed running performed in the preseason period positively influences in-season physical match activity profiles, however, are unlikely to positively impact technical match performance. [ABSTRACT FROM AUTHOR]

Purpose: To determine whether the maximal strength, impulse, and power characteristics of competitive mixed-martial-arts (MMA) athletes differ according to competition level. Methods: Twenty-nine male semiprofessional and amateur MMA competitors were stratified into either higher-level (HL) or lower-level (LL) performers on the basis of competition grade and success. The 1-repetition-maximum (1RM) squat was used to assess lower-body dynamic strength, and a spectrum of impulse, power, force, and velocity variables were evaluated during an incremental-load jump squat. In addition, participants performed an isometric midthigh pull (IMTP) and 1RM bench press to determine whole-body isometric force and upper-body dynamic strength capabilities, respectively. All force and power variables were expressed relative to body mass (BM). Results: The HL competitors produced significantly superior values across a multitude of measures. These included 1RM squat strength (1.84 ± 0.23 vs 1.56 ± 0.24 kg BM; P = .003), in addition to performance in the incremental-load jump squat that revealed greater peak power (P = .005-.002), force (P = .002-.004), and velocity (P = .002-.03) at each load. Higher measures of impulse (P = .01-.04) were noted in a number of conditions. Average power (P = .002-.02) and velocity (P = .01-.04) at all loads in addition to a series of rate-dependent measures were also superior in the HL group (P = .005-.02). The HL competitors' 1RM bench-press values approached significantly greater levels (P = .056) than the LL group's, but IMTP performance did not differ between groups. Conclusions: Maximal lower-body neuromuscular capabilities are key attributes distinguishing HL from LL MMA competitors. This information can be used to inform evidenced-based training and performance-monitoring practices. [ABSTRACT FROM AUTHOR]

Context: Repeat-high-intensity efforts (RHIEs) have recently been shown to occur at critical periods of rugby league matches. Purpose: To examine the effect that caffeine has on RHIE performance in rugby league players. Methods: Using a double-blind, placebo-controlled, crossover design, 11 semiprofessional rugby league players (age 19.0 ± 0.5 y, body mass 87.4 ± 12.9 kg, height 178.9 ± 2.6 cm) completed 2 experimental trials that involved completing an RHIE test after either caffeine (300 mg caffeine) or placebo (vitamin H) ingestion. Each trial consisted of 3 sets of 20-m sprints interspersed with bouts of tackling. During the RHIE test, 20-m-sprint time, heart rate (HR), rating of perceived exertion (RPE), and blood lactate were measured. Results: Total time to complete the nine 20-m sprints during the caffeine condition was 1.0% faster (28.46 ± 1.4 s) than during the placebo condition (28.77 ± 1.7 s) (ES = 0.18, 90%CI --0.7 to 0.1 s). This resulted in a very likely chance of caffeine being of benefit to RHIE performance (99% likely to be beneficial). These improvements were more pronounced in the early stages of the test, with a 1.3%, 1.0%, and 0.9% improvement in sprint performance during sets 1, 2, and 3 respectively. There was no significant difference in RPE across the 3 sets (P = .47, 0.48, 1.00) or mean HR (P = .36), maximal HR (P = .74), or blood lactate (P = .50) between treatment conditions. Conclusion: Preexercise ingestion of 300 mg caffeine produced practically meaningful improvements in RHIE performance in rugby league players. [ABSTRACT FROM AUTHOR]

The rapid growth in trick progression for competitive snowboarding over the past 20 years has resulted in increased physical demands required from snowboarding athletes. Despite a wealth of knowledge surrounding strength and conditioning principles for other sports, researchers are yet to address the novel strength and conditioning challenges faced by the freestyle nature of competitive snowboarding. This article, therefore, offers practitioners strategies to address the unique considerations surrounding cultural qualities, injury prevention, unstable surface training, skill acquisition, and recovery strategies for the effective implementation of strength and conditioning interventions for snowboarding athletes. [ABSTRACT FROM AUTHOR]

Competitive snowboarding (SB) has rapidly grown in popularity since its introduction into the Olympics in 1998. This growth has seen a significant increase in trick difficulty and the associated physical demands required for success. Despite the increase in physical requirements, there are currently no evidence-based recommendations that incorporate strength and conditioning or injury prevention programs. This article draws on current research that details the physical demands of SB and integrates relevant strength and conditioning principles to create an evidence-based training plan. This plan highlights the essential physical attributes for snowboard athletes that are important for successful performance and mitigating injury risk. [ABSTRACT FROM AUTHOR]

Redman, K, Steel, K, Kelly, V, and Siegler, J. Effects of a rugby league match simulation on decision-making in elite junior rugby league. J Strength Cond Res 35(7): 1972– 1980, 2021—The paucity of research on decision-making in Rugby league within the context of a match, and the potential for age and playing experience to influence decision-making ability, warrants further investigation. Therefore, the aim of this study was to determine the effects of a simulated rugby league match on decisionmaking in elite junior rugby league players. Twenty male junior rugby league players (age 15.9 ± 0.9 years, body mass 87.3 ± 14.3 kg, height 1.82 ± 0.07 m, playing experience 10.2 ± 2.4 years) completed a match simulation protocol that replicated the physiological demands of an elite junior rugby league match. Decision-making performance was measured prematch, midmatch, and postmatch simulation through a reactive agility test and video-based temporal occlusion task. Upper- and lower-body neuromuscular measures as well as ratings of perceived exertion were obtained before decision-making assessments to quantify fatigue. A 2-way mixed analysis of variance with Bonferroni corrections was used to assess changes during the simulation, and significance was accepted at p < 0.05. The main finding of this study was despite observing a decline in neuromuscular function during the match simulation protocol (countermovement jump declined 1.9 ± 0.6 cm [95% confidence intervals 0.4–3.5]; p < 0.05), this decline did not significantly affect decision-making performance (reactive agility test [p = 0.58]; temporal occlusion [p = 0.88]). These results suggest elite junior rugby league players are capable of sustaining performance during a progressively fatiguing match simulation. [ABSTRACT FROM AUTHOR]

Objectives: Aviation Rescue Firefighters (ARFF) require physical fitness specific to the aviation environment. This study aims to determine the physical fitness of ARFF and predictors of performance on ARFF-specific tasks from laboratory-based fitness measures.Design: Cross-sectional, observational study.Methods: Forty-two male ARFF (mean±SD; age 38.4±7.6 years, body mass index 26.2±2.2kgm-2) completed a physical fitness testing battery, comprising maximal aerobic capacity (V˙O2max), lactate threshold, anaerobic power, body composition (dual-energy X-ray absorptiometry), muscular strength (3 repetition maximum (3RM) bench and leg press) and muscular endurance (maximum curl ups and push ups) under controlled laboratory conditions. On a separate occasion, ARFF completed timed work-related tasks including a hose drag, dummy drag, Stihl saw hold, stair climb and simulated ARFF emergency protocol.Results: All participants finished the simulated ARFF emergency protocol under the criterion time (5min 50s); the average completion time was 4min and 31s. Performance time on the simulated ARFF emergency protocol was inversely correlated to V˙O2max (r=-0.514; p<0.001), anaerobic step test performance (r=-0.549; p<0.001), height (r=-0.325; p=0.038) and lean mass (r=-0.429; p=0.005). Higher fat mass (r=0.318; p=0.043) and % body fat (r=0.481; p=0.001) were associated with slower performance time. Muscular strength, muscular endurance and flexibility were not related to performance on the simulated ARFF emergency protocol.Conclusions: Aerobic and anaerobic capacities, as well as body composition are the strongest predictors of simulated ARFF emergency protocol performance. This study highlights the importance of aerobic and anaerobic fitness, compared to muscular strength or muscular endurance, for ARFF job-specific performance, employment and training. [ABSTRACT FROM AUTHOR]

Objectives: To explore the prevalence of obstructive sleep apnea (OSA) within a professional rugby league team and determine associations of OSA with ethnicity, positional group, and physical characteristics.Design: Observational prospective cohort study.Methods: Twenty-two professional rugby league athletes underwent one night of home-based polysomnography with apnea-hypopnea index (AHI), rapid eye movement (REM)AHI, non-REMAHI and supineAHI determined to indicate OSA. Linear models were used to assess if playing position (back or forward) or ethnicity (European-Australian or Polynesian) influenced AHI, REMAHI, non-REMAHI and supineAHI. Models were also built to determine differences according to body composition.Results: Seven athletes were classified with mild OSA (6 forwards and 1 back, 3 European-Australians, and 4 Polynesians) and three with moderate OSA (2 forwards and 1 back, 3 Polynesians). When considering ethnicity, differences were observed between Polynesians and European-Australians for REMAHI (ES=0.90, p=0.02). Increased body mass index (BMI) was associated with a moderate increase in AHI (r=0.38, p=0.04) and non-REMAHI (r=0.36, p=0.05), while higher skinfold thickness moderately related to a higher AHI (r=0.40, p=0.05) non-REMAHI (r=0.47, p=0.02), and supineAHI (r=0.41, p=0.04).Conclusions: This exploratory study found 10 cases of OSA. Polynesian athletes and athletes classified as forwards constituted the majority of reported cases, suggesting their susceptibility to OSA. Furthermore, the data suggests that athletes with greater BMI and skinfold thickness may be predisposed to OSA. [ABSTRACT FROM AUTHOR]

Objectives: To assess the magnitude of changes in, and relationships between, physical and mental fatigue pre-to-post match in elite development netballers.Design: Observational.Methods: Twelve female netballers (21.3±2.9 years) competing in the Australian Netball League reported perceptual measures of mental and physical fatigue pre- and post-match on 12 separate competition occasions. Minutes played, to allow for calculation of weighted changes (ratings proportional to playing time), positional groups and performance analysis variables were also assessed.Results: Post-match ratings were higher (p<0.01) than pre-match for both mental (pre: 31.02±19.28; post: 44.73±24.47) and physical fatigue (pre: 28.86±15.37; post: 47.21±24.67). The correlation coefficient between change in mental and physical fatigue (r=0.37, p<0.01) revealed a shared variance of 13.9%. Acute changes in mental fatigue were related to minutes played (r=0.32, p<0.01) as was change in physical fatigue (r=0.59, p<0.01). No differences in change in mental fatigue were found between positional groups (p=0.07) though change in physical fatigue was higher for shooters compared to defenders (p<0.05). Performance variables revealed no relationships with mental or physical fatigue, with the exception of turnover number with both post-match weighted physical (r= -0.23, p<0.01) and weighted-change in physical fatigue (r=-0.16, p<0.05).Conclusions: Mental and physical fatigue were found to increase across netball matches in elite development athletes. Mental fatigue emerged as a largely separate construct to physical fatigue. [ABSTRACT FROM AUTHOR]

Eukaryotic tRNA-guanine transglycosylase (TGT) – an enzyme recently recognised to be of potential therapeutic importance – catalyses base-exchange of guanine for queuine at the wobble position of tRNAs associated with 4 amino acids via a distinct mechanism to that reported for its eubacterial homologue. The presence of queuine is unequivocally required as a trigger for reaction between the enzyme and tRNA and exhibits cooperativity not seen using guanine as a substrate. [ABSTRACT FROM AUTHOR]

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