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Purpose: We tested the differences in maximum strength and various parameters of sprint performance between youth backs and forwards. Additionally, we examined the associations among various strength-sprint measures, as well as between unresisted and heavy resisted sprints. Methods: Thirty-two youth rugby players were assessed at the beginning of the season with the following tests: unresisted and resisted (50% body mass) 30-m sprints and 1-repetition maximum (1RM) in the squat exercise. Body mass, sprint velocity, and 1RM values were compared between backs and forwards using an independent t test. Pearson product–moment correlation was used to assess the relationships between absolute and relative 1RM values (rel1RM) and unresisted and resisted sprints. Results: Youth backs outperform forwards in terms of maximum velocity and under resisted sprinting conditions. Furthermore, backs exhibit higher levels of rel1RM compared with forwards. Our findings indicate significant correlations between resisted and unresisted sprinting for several sprint qualities when considering all players together. When participants were divided into different groups, stronger correlations between resisted and unresisted sprints were found among slower/heavier players (forwards). Notably, for faster players (backs), there was no significant correlation between heavy resisted sprints and maximum velocity (r =.25; P =.4). Last, despite their lower rel1RM values compared with backs, for forwards the rel1RM is closely associated with unresisted and resisted sprints. Conclusion: Unlike youth forwards, for youth backs, the ability to sprint faster with heavy sled loads is not associated with the maximum velocity achieved in linear sprints, and higher values of rel1RM do not necessarily lead to improved sprint performance. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the relationships between a series of direct and indirect measures of linear and multidirectional speed performance in elite female rugby sevens players. Methods: Nineteen players from the Brazilian national team performed 40-m linear sprint and 505 change-of-direction (COD) tests on the same day. Based on the linear sprint and COD test performances, the COD deficit (CODD) and deceleration deficit (DD) were also obtained. A Pearson product–moment correlation analysis was used to determine the relationships between linear sprint and COD-derived variables. Results: Linear sprint and 505 COD velocities were not significantly associated (P >.05). Large to very large significant associations (r values ranging from.54 to.78; P <.05) were detected between linear sprint velocity for the different distances tested (10, 15, 30, and 40 m) and CODD. The COD velocity presented a very large inverse significant correlation with CODD and DD (r = −.77 and −.79 respectively; P <.05). A large and significant correlation was identified between CODD and DD (r =.79; P <.05). Conclusions: Significant associations were observed between linear sprint and CODD, suggesting that faster players are less efficient at changing direction. No relationship was found between sprint velocity and DD, highlighting the independent nature of linear sprints and deceleration capabilities. A comprehensive and detailed analysis of multidirectional speed performance should consider not only linear sprint and COD performances but also complementary COD-derived variables such as the CODD and DD. [ABSTRACT FROM AUTHOR]

Post-activation performance enhancement (PAPE) is a key objective following regular warm-up routines, especially in sports that rely heavily on sprinting speed and power. Rugby is a team sport characterized by a range of repeated high-intensity efforts, irrespective of positional roles or match demands. In this study, we examined and compared the effects of two different conditioning activities (CAs) on the power- and speed-related abilities of National Team rugby players. Thirteen male rugby union players sequentially performed countermovement jump (CMJ), 30 m sprint, and change-of-direction (COD) tests (pre-testing session) 5 min before executing either one set of six repetitions of 45 cm drop jumps or one set of six repetitions of flywheel eccentric-overload squats. In addition to the sport-specific tests, the muscle mechanical properties of the athletes were also assessed through the use of tensiomyography (TMG). At post-testing sessions conducted 5 and 10 min after the PAPE protocols, no significant changes were observed in any of the assessed variables, either in positions as backs or forwards. However, some meaningful variations were detected at the individual level when using the "true-changes" analysis. Despite some positive individual changes, it can be concluded that these specific protocols did not elicit the expected responses typically observed in other team-sport athletes. Practitioners are encouraged to implement more comprehensive (but not exhaustive) and tailored PAPE interventions prior to training sessions and competitions. [ABSTRACT FROM AUTHOR]

The maximum velocity achieved during sprinting is a crucial aspect in various sports. Therefore, practitioners use various devices, such as laser or radar guns, timing gates (TG), and global positioning systems (GPS), to assess sprint performance. Although highature speed cameras are considered the most accurate equipment for assessmeasuring ing maximum velocity (Vmax), TG are more commonly used because of their practicality and affordability. Recently, GPS technology has gained attention from the sport science community, primarily because of its applied charcurrent acteristics, enabling "in situ" data exploration. However, there is currently no consensus on the validity, reliability, and sensitivity of GPS in field-based team sports not only for measuring Vmax but also for tracking potential changes in sprint performance. We thoroughly examined the existing liter-highature on the validity, reliability, and sensitivity of GPS technology for assessmeasuring Vmax, with a specific emphasis on its application in team sports. Furthermore, we offer a comprehensive discussion on the capability of these devices to assess potential variations in Vmax. By synthesizing charcurrent research findings, this narrative review sheds light on the strengths and limitations of GPS devices for as-sessing Vmax in field-based team sport athletes. [ABSTRACT FROM AUTHOR]

Purpose: To compare the strength, speed, and power performance of elite sprinters with and without visual impairment. Methods: Twelve elite able-bodied sprinters and 15 Paralympic sprinters with visual impairment took part in this study. Sprinters from both groups performed the following tests: squat and countermovement jumps, maximum bar-power output in the half-squat and jump-squat exercises, and 60-m sprint. The differences between groups in all variables examined were analyzed using the independent t test. Results: Olympic sprinters revealed better performances in all tests when compared with Paralympic sprinters with visual impairment (effect sizes ranging from 1.29 to 9.04; P <.001). Differences of ∼32% and ∼20% were found for the half-squat and loaded and unloaded vertical jumps, respectively. Smaller differences (from ∼8% to ∼11%) were obtained in linear sprint performance. Conclusions: Between-groups differences peaked at low-velocity exercises (eg, ∼32% in the half-squat) and decreased as movement velocity and specificity increased (eg, ∼8% at 60-m sprint). Thus, the greatest differences between Olympic and Paralympic sprinters seem to be related to their ability to apply force at low movement velocities. Coaches are encouraged to work on all sprinting phases and across the entire force–velocity spectrum, bearing in mind that improvements in strength capacity will possibly lead to increased sprint performance in Paralympic sprinters with visual impairment, especially in the acceleration phase of sprinting. [ABSTRACT FROM AUTHOR]

This study assessed the validity of 5-m (TG5) and 10-m (TG10) split times measured with timing gates to estimate maximum sprint speed (MSS) against a criterion measure radar gun (RG) during the maximum velocity phase of a 30-m sprint. Nineteen amateur rugby players performed two 30-m sprints. The timing gates were placed at the starting line and at 5-, 10-, 20-, 25- and 30-m. In addition, a RG was used to measure instantaneous velocity. Both trials per participant were used selected as references. MSS obtained from TG10, TG5 and RG showed high intraclass correlation coefficients (0.971–0.978), low coefficients of variation (1.14–1.70%) and smallest detectable changes (<0.02 m/s). Pairwise comparison revealed differences (p = 0.002) in MSS when comparing TG10 to RG, but not TG5 and RG (p = 0.957). Almost perfect correlations were found between RG, TG5 and TG10 (r > 0.926, p < 0.001). In conclusion, MSS obtained from TG5, TG10 and RG presented good intra-session reliability. However, practitioners should be aware that substantial differences exist between TG10 and RG. For the assessment of MSS in team-sport athletes, it is recommended the use of TG5 for more accurate estimations when a gold standard criterion is not available. [ABSTRACT FROM AUTHOR]

Introduction: Warm-up is a primordial element to optimise sport performance in both training and competitions. The main objective of this study was to compare the acute effect of two warm-up protocols for physical and technical-decisional performance in U16 football players. Material and Methods: We applied an integrated warm-up protocol (IWP) of 5 vs 5 in a small space of 20x28 m and an analytical warm-up protocol (AWP) of 12 dynamic exercises that are commonly used in football. Each warm-up was carried out 7 days apart and alternated. After each warm-up, the intensity of the load was recorded through the rate of perceived exertion (RPE), physical performance was recorded using the T30 speed test (time to sprint 30 m) and the kicking speed test, and the Loughborough Soccer Passing Test (LSPT) was applied, which evaluates the football skills of passing and decision making. Results: The results show greater technical-decisional performance in LSPT (p = 0.020, ES = 0.55 small) after executing the IWP. However, in T30 (p = 0.129, ES = 0.417 small) and kicking (p = 0.374, ES = -0.29 small), no significant differences were observed. Conclusion: IWP presents greater performance in the technical-decisional test of LSPT, and both warm-up protocols have a similar component of intensity and performance in T30 and kicking. [ABSTRACT FROM AUTHOR]

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The aim of this study was to compare the peak force (PF), peak power (PP), and peak velocity (PV) outputs produced during half-squat (HS) and jump squat (JS) exercises executed at 20, 40, 60, and 80% of 1 repetition maximum (1RM) in the HS (HS 1RM) and to compute and compare the strength deficit (SDef) achieved in these exercises across these loads. Twenty-four national rugby union players (age: 25.7 ± 3.6 years) performed HS 1RM and a progressive loading test in the HS and JS exercises. The PF, PP, and PV values were obtained in all loads for both exercises, and the SDef was calculated as the percentage difference between the PF at distinct relative intensities and the PF at HS 1RM. The differences in HS and JS variables were determined using an analysis of variance with repeated measures. Higher PF, PP, and PV outputs were generated in the JS in comparison with the HS exercise (p < 0.05); moreover, the SDef magnitudes were significantly lower in the JS (p < 0.01), for all loading conditions. Importantly, the differences in SDef, and as a consequence, PF, PP, and PV decreased progressively with increasing load. Overall, the loaded JS exhibited increased levels of PF, PP, and PV and reduced levels of SDef when compared to the traditional HS performed across a range of loads. The JS is indicated to reduce the SDef and improve the athletes’ ability to apply force at higher velocities. Nevertheless, with heavier loads (i.e.,≥80% HS 1RM), its potential advantages and effectiveness may be seriously compromised. [ABSTRACT FROM AUTHOR]

Pareja-Blanco, F, Pereira, LA, Freitas, TT, Alcaraz, PE, Reis, VP, Guerriero, A, Arruda, AFS, Zabaloy, S, De Villarreal, ES, and Loturco, I. Acute effects of progressive sled loading on resisted sprint performance and kinematics. J Strength Cond Res 36(6): 1524–1531, 2022—We examined the effects of 5 loading conditions (0, 20, 40, 60, and 80% of body-mass [BM]) on resisted sprint performance and kinematics in male rugby players over different distances. Ten players from the Brazilian National Team (20.1 ± 3.3 years; 88.7 ± 18.8 kg; 178.3 ± 6.2 cm) performed 20-m sprints under the 5 loading conditions. Sprint times in 5, 10, and 20 m were recorded. Stride length (SL), and hip, knee, and ankle angles were measured using an eight-sensor motion analysis system. The kinematic parameters were calculated over the different distances. Heavier loads led to significantly greater velocity loss (p < 0.001–0.05). Significant reductions in SL were also observed when comparing 0% BM and all resisted sprints in all assessed distances (p < 0.001–0.05, effect size [ES]: 1.35–4.99). Very heavy (80% BM) sled load provoked significantly greater decreases in SL than the rest of loading conditions (p < 0.01–0.05). Important kinematic alterations were observed for all loading conditions and sprint distances when compared with 0% BM (ES: 0.76–1.79, for hip-angle; 0.20–1.40, for knee-angle; and 0.73–1.88, for ankle-angle). Moreover, 80% BM induced significantly higher hip flexion, lower knee flexion, and higher ankle dorsiflexion than 20% BM condition at 5–10 and 10–20 m distances (p < 0.05). Lighter sled loads (<40% BM) seem to be more adequate to improve speed ability without provoking drastic changes in the unloaded sprinting technique, whereas heavier loads may be more suitable for optimizing horizontal force production and thus, acceleration performance. [ABSTRACT FROM AUTHOR]

Purpose: We tested the differences in maximum strength and various parameters of sprint performance between youth backs and forwards. Additionally, we examined the associations among various strength-sprint measures, as well as between unresisted and heavy resisted sprints., Methods: Thirty-two youth rugby players were assessed at the beginning of the season with the following tests: unresisted and resisted (50% body mass) 30-m sprints and 1-repetition maximum (1RM) in the squat exercise. Body mass, sprint velocity, and 1RM values were compared between backs and forwards using an independent t test. Pearson product-moment correlation was used to assess the relationships between absolute and relative 1RM values (rel1RM) and unresisted and resisted sprints., Results: Youth backs outperform forwards in terms of maximum velocity and under resisted sprinting conditions. Furthermore, backs exhibit higher levels of rel1RM compared with forwards. Our findings indicate significant correlations between resisted and unresisted sprinting for several sprint qualities when considering all players together. When participants were divided into different groups, stronger correlations between resisted and unresisted sprints were found among slower/heavier players (forwards). Notably, for faster players (backs), there was no significant correlation between heavy resisted sprints and maximum velocity (r = .25; P = .4). Last, despite their lower rel1RM values compared with backs, for forwards the rel1RM is closely associated with unresisted and resisted sprints., Conclusion: Unlike youth forwards, for youth backs, the ability to sprint faster with heavy sled loads is not associated with the maximum velocity achieved in linear sprints, and higher values of rel1RM do not necessarily lead to improved sprint performance.

This study aimed to determine, through the use of a highly sensitive statistical tool, whether real changes in performance were present; and compare the rates of meaningful variations in strength, speed, and power parameters at different time-points during the competitive season in national team rugby players. Thirty-two players were assessed 5 times across the season using the following tests: squat jump and countermovement jump tests; 30-m sprint velocity; and one-repetition maximum (1RM) in the half-squat and bench-press exercises. A repeated-measures analysis of variance was conducted to test for differences between successive time-points. Individual coefficients of variation values were used to set target scores for post-measurements and examine whether changes in performance parameters were greater than the natural test variance, thus providing an indication of whether "true changes" occurred. No significant changes were detected in the vertical jump height, 1RM measures, and sprint velocity and momentum throughout the 11-month period ( P > 0.05). True changes occurred much more frequently for strength-power measures than for sprint velocity and momentum. Elite rugby union players did not exhibit significant variations in neuromuscular performance across the competitive period, when a group-based analysis was conducted. However, at the individual level, "true changes" in strength-power-(but not in speed-) related qualities were consistently observed over the competitive season., Competing Interests: The authors declare no conflict of interest., (Copyright © Institute of Sport – National Research Instutite.)