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Purpose: To examine associations between exercise heart rate (HRex) during a continuous-fixed submaximal fitness test (CF-SMFT) and an intermittent-variable protocol (semistandardized kicking drill [SSD]) in Australian Football athletes, controlling for external intensities, within-session scheduling, and environmental conditions. Methods: Forty-four professional male Australian Football athletes (22.8 [8.0] y) were monitored over 10 sessions involving a 3-minute CF-SMFT (12 km·h−1) as the first activity and a SSD administered 35.7 (8.0) minutes after the CF-SMFT. Initial heart rate and HRex were collected, with external intensities measured as average velocity (in meters per minute) and average acceleration–deceleration (in meters per second squared). Environmental conditions were sampled. A penalized hierarchical linear mixed model was tuned for a Bayesian information criterion minima using a 10-fold cross-validation, with out-of-sample prediction accuracy assessed via root-mean-squared error. Results: SSD average acceleration–deceleration, initial heart rate, temperature, and ground hardness were significant moderators in the tuned model. When model covariates were held constant, a 1%-point change in SSD HRex associated with a 0.4%-point change in CF-SMFT HRex (95% CI, 0.3–0.5). The tuned model predicted CF-SMFT HRex with an average root-mean-squared error of 2.64 (0.57) over the 10-fold cross-validation, with 74% and 86% of out-of-sample predictions falling within 2.7%-points and 3.7%-points, respectively, from observed values, representing the lower and upper limits for detecting meaningful changes in HRex according to the documented typical error. Conclusions: Our findings support the use of an SSD to monitor physiological state in Australian Football athletes, despite varied scheduling within session. Model predictions of CF-SMFT HRex from SSD HRex closely aligned with observed values, considering measurement imprecision. [ABSTRACT FROM AUTHOR]

Sprint performance is commonly assessed via discrete sprint tests and analyzed through kinematic estimates modeled using a mono-exponential equation, including estimated maximal sprinting speed ( M S S ), relative acceleration ( T A U ), maximum acceleration ( M A C ), and relative propulsive maximal power ( P M A X ). The acceleration–velocity profile (AVP) provides a simple summary of short sprint performance using two parameters: MSS and MAC, which are useful for simplifying descriptions of sprint performance, comparison between athletes and groups of athletes, and estimating changes in performance over time or due to training intervention. However, discrete testing poses logistical challenges and defines an athlete's AVP exclusively from the performance achieved in an isolated testing environment. Recently, an in situ AVP (velocity–acceleration method) was proposed to estimate kinematic parameters from velocity and acceleration data obtained via global or local positioning systems (GPS/LPS) over multiple training sessions, plausibly improving the time efficiency of sprint monitoring and increasing the sample size that defines the athlete's AVP. However, the validity and sensitivity of estimates derived from the velocity–acceleration method in relation to changes in criterion scores remain elusive. To assess the concurrent validity and sensitivity of kinematic measures from the velocity–acceleration method, 31 elite youth basketball athletes (23 males and 8 females) completed two maximal effort 30 m sprint trials. Performance was simultaneously measured by a laser gun and an LPS (Kinexon), with kinematic parameters estimated using the time–velocity and velocity–acceleration methods. Agreement ( % B i a s ) between laser gun and LPS-derived estimates was within the practically significant magnitude ( ± 5%), while confidence intervals for the percentage mean absolute difference ( % M A D ) overlapped practical significance for T A U , M A C , and P M A X using the velocity–acceleration method. Only the M S S parameter showed a sensitivity ( % M D C 95 ) within practical significance (<5%), with all other parameters showing unsatisfactory sensitivity (>10%) for both the time–velocity and velocity–acceleration methods. Thus, sports practitioners may be confident in the concurrent validity and sensitivity of M S S estimates derived in situ using the velocity–acceleration method, while caution should be applied when using this method to infer an athlete's maximal acceleration capabilities. [ABSTRACT FROM AUTHOR]

Although research has enhanced our understanding of inter-tier differences in match demands within elite 15-a-side rugby union, current understanding of differences between tournament tiers of elite-international rugby sevens (RS) is limited. The present study aimed to compare match demands across three tiers of elite-international RS by position and tournament round, and to analyse the demands recorded by Full-match players relative to Substitutes. Match demands were quantified via Global-positioning system (10Hz) and triaxial load (100Hz) data. Nineteen matches were monitored (4 tournaments; Pool: 134, Cup: 81), totalling 215 player-observations (Backs: 17, Forwards: 5). Standard mean differences (ES) were analysed. Backs recorded greater demands than Forwards across 82% of the variables. Relative PlayerLoadTM was greater during World Series (WS) (Backs: 14.6±1.8, Forwards: 12.4±1.3 AU·min−1) and World Cup Qualifier (WCQ) (Backs: 14.7±1.8, Forwards: 13.1±1.3 AU·min−1) than Olympic Qualifier (OQ) (Backs: 11.3±1.5, Forwards: 9.2±1.0 AU·min−1) matches. Differences between Pool and Cup matches for relative high-intensity distance, accelerations, and decelerations were trivial-to-small (ES range: -0.08–0.35). Substitutes recorded greater relative distances than Full-match players (ES range: 0.36–0.77), with moderate differences in sprint (Full-match: 0.5±0.2, Substitutes: 0.7 ± 0.3 count·min−1) and acceleration counts (Full-match: 1.8±0.6, Substitutes: 2.3±1.0 count·min−1) amongst forwards. A trend indicated Substitutes covered greater relative distances at high-velocities in both groups (ES range: 0.01–0.62). High-performance practitioners in elite-international RS should consider: Backs achieve higher running volumes and intensities per-match than Forwards; demands are similar between WCQ and WS matches, both of which tended to be superior to OQ matches; Pool and Cup matches elicited similar demands; and substitutes should be prepared to perform at higher-intensities per-minute of involvement than players completing full-matches. [ABSTRACT FROM AUTHOR]

Though research has developed an understanding of the physical demands of male basketball competition, less is known regarding professional female basketball. Advancements in load monitoring -- e.g., accelerometer technology -- have allowed practitioners to detect movement patterns in indoor sports. The aims of this study were to document the microsensor derived physical demands of match play and investigate differences in physical demands across match quarters and positions in professional female basketball. Fourteen athletes from a professional basketball team were observed over 10 matches. Data were collected using microsensor technology; units were worn by players inside sports vests. Outcome variables included: Actual Playing Time, PlayerLoadTM, Inertial Movement Analysis (IMA) variables and Repeated High-Intensity Efforts (RHIE). Data were analysed for statistical differences using a two-way Analysis of Variance test and post-hoc Bonferroni test for multiple comparisons. Guards experienced significantly greater Actual Playing Time (61.24 ± 20.20 min) and PlayerLoadTM (485.60 ± 158.08 arbitrary units, AU) compared to Forwards (52.60 ± 20.72 min, 411.56 ± 161.84 AU) and Centres (46.24 ± 19.08 min, 394.44 ± 166.96 AU) (all p values <0.05). Guards performed more total jumps (27.32 ± 17.60) compared with forwards (21.80 ± 13.20) (p = 0.046), while centres performed more jumps per minute (0.59 ± 0.93 jumps.min-1) compared with forwards (0.42 ± 0.64 jumps.min-1) (p = 0.041). The only significant difference in movement variables across quarters observed was greater relative RHIE in quarter 4 compared to quarter 3 (0.016 ± 0.013 vs 0.008 ± 0.012 bouts per minute). It is recommended that guards complete longer duration metabolic conditioning drills compared to forwards and centres. Coaches should also include conditioning strategies that increase high-intensity efforts later in the conditioning session. [ABSTRACT FROM AUTHOR]

This article, titled "Average Velocity and Average Acceleration in World Series Rugby Sevens," explores the differences in external intensity between forwards and backs in rugby sevens. The study collected GPS data from 22 international rugby sevens players and found that backs had significantly higher average velocity and average acceleration compared to forwards. The study also found a strong positive correlation between average velocity and average acceleration in both positional groups. The findings suggest that practitioners should consider these positional differences when planning the physical preparation of rugby sevens players. Further research is needed to determine the effectiveness of average acceleration in monitoring intensity during close-contact activities in rugby sevens. [Extracted from the article]

This article, titled "Effects of Acute Locomotor Load on Eccentric Hamstring Strength Indices: A Preliminary Investigation in Professional Australian Football," explores the relationship between acute locomotor load and eccentric hamstring strength in professional Australian football players. The study found that the maximum force produced during the Nordic exercise was inversely related to the acute meterage covered at individualized high-speed zones. The authors suggest that high-performance practitioners should consider acute locomotor load when interpreting eccentric hamstring strength indices. The study highlights the importance of considering factors such as neuromuscular fatigue and training load in assessing hamstring injury risk in Australian football players. [Extracted from the article]