Weekly Programming of Hamstring-Related Training Contents in European Professional Soccer.

Hamstring injuries in soccer continue to be a challenge for professionals who work with soccer players daily. Although its origin is multifactorial, the proper management of neuromuscular fatigue during the training microcycle is a very important factor to consider. There are no clear guidelines regarding the weekly distribution of certain exercises that demand the hamstrings. The main objective of this study was to describe the usual training practices of professional European soccer teams. An international observational survey design was applied to some of the strength and conditioning coaches of professional soccer teams. The survey included different neuromuscular demanding exercises for the hamstrings. For each exercise, the strength and conditioning coaches had to respond in relation to their frequency of use and timepoint depending on the day of the weekly microcycle. Although there is no strong consensus in this regard, there does seem to be a trend when applying certain exercises, especially on the days matchday-4 and matchday-3.

Exploring countermovement jump variables across competitive levels and playing positions in futsal.

Introduction: The aims of this study were to compare several countermovement jump (CMJ) kinetic variables between professional (PRO) and semi-professional (SEMI-PRO) futsal players and examine the differences amongst playing positions. Methods: CMJ performance from 56 male futsal players (25.2 ± 4.8 years; weight: 74.4 ± 6.4 kg) was analysed. Players were separated into PRO (n = 29; 27.0 ± 4.4 years; 75.4 ± 6.0 kg) and SEMI-PRO (n = 27; 22.7 ± 4.3 years; 73.1 ± 6.8 kg), and according to playing position: defenders (n = 16; 25.4 ± 3.7 years; 75.2 ± 6.0 kg), wingers (n = 26; 23.5 ± 4.5 years; 72.0 ± 6.9 kg), and pivots (n = 14; 28.0 ± 5.6 years; 77.8 ± 4.3 kg). Linear mixed models and effect sizes were used for the analyses based on the mean of two jumps for each variable. Results: PRO players presented a deeper center of mass (COM) displacement (p = 0.002, ES = 0.83), greater eccentric (Ecc) absolute (p = 0.019, ES = 0.61) and relative peak power (p = 0.046, ES = 0.52), and achieved greater Ecc peak velocities (p = 0.004, ES = 0.76) when compared to SEMI-PRO. Non-significant and trivial-to-small differences were observed in all the other CMJ variables according to the competitive level and playing position. Discussion: Ecc capabilities (i.e., deeper COM displacement, greater Ecc absolute and relative peak power, and peak velocity) during vertical jump seem to differentiate PRO and SEMI-PRO players. However, CMJ variables do not discriminate amongst playing positions in futsal players.

Resistance Training Practices of Brazilian Olympic Sprint and Jump Coaches: Toward a Deeper Understanding of Their Choices and Insights (Part III).

In the final part of this three-article collection on the training strategies of Brazilian Olympic sprint and jump coaches, we provide a detailed description of the resistance training methods and exercises most commonly employed by these speed experts. Always with the objective of maximizing the sprint and jump capabilities of their athletes, these experienced coaches primarily utilize variable, eccentric, concentric, machine-based, isometric, complex, and isoinertial resistance training methods in their daily practices. Squats (in their different forms), Olympic weightlifting, ballistics, hip thrusts, lunges, calf raises, core exercises, leg curls, stiff-leg deadlifts, and leg extension are the most commonly prescribed exercises in their training programs, during both the preparatory and competitive periods. Therefore, the current manuscript comprehensively describes and examines these methods, with the additional aim of extrapolating their application to other sports, especially those where sprint speed is a key performance factor.

Speed Training Practices of Brazilian Olympic Sprint and Jump Coaches: Toward a Deeper Understanding of Their Choices and Insights (Part II).

This is the second article in a three-article collection regarding the plyometric, speed, and resistance training practices of Brazilian Olympic sprint and jump coaches. Here, we list and describe six out of the ten speed training methods most commonly employed by these experts to enhance the sprinting capabilities of their athletes. Maximum speed sprinting, form running, resisted sprinting, overspeed running, uphill and downhill running, and sport-specific movement methods are critically examined with reference to their potential application in different sport contexts. In an era when sprint speed is of critical importance across numerous sports, practitioners can employ the methods outlined here to design efficient training programs for their athletes.

Sand and grass surfaces are equally effective in promoting positive adaptations in the sprint performance of elite young soccer players.

This study compared the effects of two sprint-jump training programmes, performed on either sand or grass surfaces, on the sprint and jump performance of elite young soccer players over an 8-week training period. Fifteen under-20 soccer players were randomly allocated to the sand (n = 7) or grass (n = 8) group. Athletes performed 12 training sessions, comprising vertical and horizontal jump exercises, and linear and change-of-direction (COD) sprint drills. Pre- and post-measurements were completed in the following order: vertical jump, sprint speed at 10 m and 17 m, curve sprint (CS), and modified Zigzag COD tests. Between-group differences were determined using a two-way ANOVA with repeated measures and effect sizes (ES). No improvements in jump performance were found in either group. Significant increases were observed in the sand group for acceleration in 0-10 m and for 10- and 17-m linear sprint velocity (ES = 1.15, 1.16, and 1.81, respectively; P < 0.05). In contrast, no significant differences were detected for acceleration and linear sprint velocity in the grass group, comparing pre- and post-tests (ES ranging from 0.01 to 0.47; P > 0.05). Both sand and grass groups revealed similar increases in the CS and COD velocities after the training period (ES ranging from 0.98 to 1.93; P < 0.05). In conclusion, sprint-jump training programmes performed on both grass and sand surfaces elicited significant improvements in CS and COD performances, whereas acceleration and linear sprint velocity increased only in the sand group, after a short-term training period. The sand training surface was proven to be a practical strategy to improve sprint performance in all its forms in soccer players, which is of great interest and importance for coaches and sport scientists working in elite soccer.

Interpreting match performance in elite futsal: considerations for normalizing variables using effective time.

Introduction: This study aimed to investigate the physical and individual technical-tactical performance of elite futsal players. Methods: Thirteen National Team futsal players (27.4 ± 4.7 years, 70.3 ± 7.6 kg, 176.3 ± 5.5 cm) competed in 15 official matches in three distinct competitions. Session rate of perceived exertion (sRPE) and player load (PL) were measured for assessing physical internal and external load, respectively. Individual tactical actions were analyzed using Instat Scout®, considering variables such as fouls, shots, shots on target, goals, successful dribbles, passes, successful passes, ball losses, ball recoveries, and challenges won. Results: The cluster analysis classified the players into two groups: "high-involvement" (HIGH) and "low-involvement" (LOW), based on their average effective playing time, sRPE, and PL. A linear mixed model was used to examine the differences in external and internal load and technical-tactical variables between the two groups, accounting for individual repeated measures. Considering absolute values, HIGH players presented higher sRPE, RPE, total PL, shots, goals, passes, successful passes, ball losses and recoveries, and challenges won (p = 0.001-0.039; ES = 0.43-2.48), when compared to their LOW counterparts. However, when analyzed relative to effective time, LOW players reached higher total PL and shots per minute (p = 0.001-0.012; ES = 0.39-0.93) when compared to HIGH players. Non-significant differences were found for the rest of the variables. Discussion: In summary, these results emphasize the importance of normalizing internal and external load variables and technical-tactical performance variables per effective playing time in futsal. The current findings indicate that players with lower involvement can present the same or even higher physical and technical-tactical performance compared to teammates with more playing time.

Plyometric Training Practices of Brazilian Olympic Sprint and Jump Coaches: Toward a Deeper Understanding of Their Choices and Insights.

Plyometric training is extensively used by coaches to enhance neuromuscular performance in a wide variety of sports. Due to the high demands of sprint speed and power output in elite sprinters and jumpers, sprint and jump coaches are likely to have great knowledge on this topic. Undoubtedly, this expertise is even more pronounced for Olympic coaches, who work with some of the fastest and most powerful athletes in the world, and who are required to continually maintain these athletes at optimal performance levels. Describing and discussing the practices commonly adopted by these coaches in detail and extrapolating this experience to other sport coaching contexts and disciplines may be extremely relevant. The current article presents, explores, and illustrates the plyometric training practices of Brazilian Olympic sprint and jump coaches, with a special focus on training programming and exercise selection.

Change-of-Direction and Deceleration Deficits in National-Team Female Rugby Sevens Players: Interrelationships and Associations With Speed-Related Performance.

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.

Mixed Training Programs Applied to Young Soccer Players: Effects on Speed-Power Abilities.

We compared the effects of two 4-week strength-power-speed training protocols on physical performance of young soccer players. Twenty-three highly trained under-20 soccer players were randomly allocated to two mixed-training groups: 1) "traditional" (TRAD: n=11), comprising vertically oriented strength-power exercises and linear sprints; or 2) "multidirectional" (MULTI: n=12), combining vertically and horizontally oriented strength-power exercises, linear sprints, and change-of-direction (COD) drills. Squat jump (SJ) and countermovement jump, 2) linear sprint, COD speed, and 3) jump-squat (JS) and hip-thrust (HT) power tests were performed pre- and post-training. Differences were determined using a two-way ANOVA with repeated measures and "target scores" were used to detect real changes in performance. No group-time interactions were found for any of the variables (p>0.05). Significant increases (p<0.05) in 20-m sprint velocity, JS- and HT-power were found in both groups, and in SJ in TRAD. Individual analyses revealed a greater number of meaningful changes in zig-zag velocity in MULTI while most players in TRAD displayed meaningful increases in SJ height. In conclusion, both training protocols resulted in similar adaptations but, at the individual level, it appears that MULTI protocol is superior to improve COD ability while TRAD should be preferred to maximize vertical jumping capabilities during short soccer pre-seasons.

SCS 5th Annual Conference. São Paulo, Brazil, 2022.

On behalf of the Strength and Conditioning Society (SCS) and the Nucleus of High Performance in Sport (NAR), we are pleased to present the abstracts of the SCS 5th Annual Conference, which, for the first time, took place outside of Europe. The event was held at NAR's state-of-the-art facilities in São Paulo, Brazil, on 3-5 November 2022, and comprised several invited sessions from international and national speakers on a variety of topics related to strength and conditioning practices and their application to health, injury prevention and sports performance. These included strength training in high-performance sports and older adults, sleep and recovery in elite athletes, performance optimization of the female athlete, high-intensity interval training, velocity-based resistance training, and running and cycling biomechanics, among others. The Conference also included different practical workshops conducted by renowned academics and practitioners on post-competition recovery strategies, plyometric training, hamstring strain injuries in soccer, and resisted sprint training. Finally, the event disseminated up-to-date strength and conditioning research by providing practitioners and researchers with the opportunity to present their most recent findings. In this regard, all abstracts of the communications presented at the SCS 5th Annual Conference can be found in this Conference Report.

Strength and Conditioning Practices of Brazilian Olympic Sprint and Jump Coaches.

Olympic coaches are likely to have adequate knowledge and implement effective training programs. This study aimed to describe and critically examine the strength and conditioning practices adopted by Brazilian Olympic sprint and jump coaches. Nineteen Olympic coaches (age: 50.2 ± 10.8 years; professional experience: 25.9 ± 13.1 years) completed a survey consisting of eight sections: 1) background information; 2) strength-power development; 3) speed training; 4) plyometrics; 5) flexibility training; 6) physical testing; 7) technology use; and 8) programming. It was noticed that coaches prioritized the development of explosiveness, power, and sprinting speed in their training programs, given the specific requirements of sprint and jump events. Nevertheless, unexpectedly, we observed: (1) large variations in the number of repetitions performed per set during resistance training in the off-season period, (2) a higher volume of resistance training prescribed during the competitive period (compared to other sports), and (3) infrequent use of traditional periodization models. These findings are probably related to the complex characteristics of modern competitive sports (e.g., congested competitive schedule) and the individual needs of sprinters and jumpers. Identification of training practices commonly used by leading track and field coaches may help practitioners and sport scientists create more effective research projects and training programs.

Half-Squat and Jump Squat Exercises Performed Across a Range of Loads: Differences in Mechanical Outputs and Strength Deficits.

ABSTRACT: Loturco, I, McGuigan, MR, Freitas, TT, Bishop, C, Zabaloy, S, Mercer, VP, Moura, TBMA, Arruda, AFS, Ramos, MS, Pereira, LA, and Pareja-Blanco, F. Half-squat and jump squat exercises performed across a range of loads: differences in mechanical outputs and strength deficits. J Strength Cond Res 37(5): 1052-1056, 2023-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.

Interrelationships Between Multiple Speed Tests in Youth Soccer: Are Players Equally Efficient at Performing Different Sprint and Change of Direction Tasks?

ABSTRACT: Freitas, TT, Pereira, LA, Alcaraz, PE, Cadore, EL, Grazioli, R, Azevedo, PHSM, Jeffreys, I, and Loturco, I. Interrelationships between multiple speed tests in youth soccer: Are players equally efficient at performing different sprint and COD tasks? J Strength Cond Res 37(4): 848-853, 2023-We investigated the relationships between linear and multidirectional sprint tests in elite young soccer players, using different speed measurements and their associated deficits. Twenty-three under-17 and 17 under-16 soccer players performed, on the same day, 17-m linear sprint (with 10-m split times), curve sprints for "good" and "weak" sides (CSGS and CSWS, respectively), and zigzag and 505 change of direction (COD) tests. The Pearson's product moment test was used to determine the relationships among the tested variables. Significance level was set at p < 0.05. Large and very large significant correlations were observed between CSGS and CSWS and 10-m ( r = 0.73 and r = 0.53, respectively; p < 0.0001) and 17-m sprint velocity ( r = 0.84 and r = 0.74, respectively; p < 0.0001). Moderate and significant associations were identified between zigzag and 17-m sprint performances ( r = 0.40; p = 0.02). No significant relationships were found between 505 performance and 17-m sprint velocity and between the different COD tasks ( p > 0.05). Significant correlations were observed between sprint performance at 10- and 17-m and both CS and COD deficits ( r values ranging from 0.37 to 0.54; p < 0.05). In general, higher linear sprinting velocities were associated with superior performances in smoother multidirectional tasks (i.e., CS and zigzag tests) but not in more aggressive COD maneuvers (i.e., 505). Faster athletes in linear actions presented greater CS and COD deficits. No associations were detected between the different COD measurements, supporting the notion that the technical and mechanical demands of COD actions are angle and velocity dependent. From a practical perspective, comprehensive speed testing batteries (i.e., incorporating linear sprints, CS, and different COD assessments) should be administered to young soccer players, to better understand their ability to change direction and sprint over multiple trajectories.

Neuromuscular Performance Changes in Elite Futsal Players Over a Competitive Season.

ABSTRACT: Spyrou, K, Alcaraz, PE, Marín-Cascales, E, Herrero-Carrasco, R, Cohen, DD, and Freitas, TT. Neuromuscular performance changes in elite futsal players over a competitive season. J Strength Cond Res 37(5): 1111-1116, 2023-A professional futsal season imposes a great amount of physiological and mechanical stress on players. The main aim of this study was to examine the changes in neuromuscular performance qualities across the season. Ten professional male players performed a 10-m sprint, standing long jumps (SLJs), and countermovement jumps (CMJs) during the competitive season (i.e., every ∼5 weeks from September to January). A one-way repeated measures ANOVA with post hoc pairwise comparisons and effect sizes (ESs) were used to analyze potential differences among these assessments. A significant and large decline was found in concentric peak power ( p = 0.040; ES = 1.24). A nonsignificant and moderate decrease was observed in sprint ability ( p = 0.155; ES = 1.03), CMJ height ( p = 0.175; ES = 1.00), and SLJ distance ( p = 0.164; ES = 1.03). Regarding other CMJ kinetic variables, nonsignificant and moderate changes were found. In summary, considering the neuromuscular performance tests and variables assessed, only concentric peak power in CMJ decreased significantly across the season; however, nonsignificant decrements were observed in sprinting time, SLJ, CMJ height, and other kinetic metrics. CMJ variables during the jump-land cycle should be incorporated alongside more traditional measures (e.g., jump height) to monitor performance during the season.

Sprint and Jump Training on Sand vs. Grass Surfaces: Effects on the Physical Performance of Young Soccer Players.

ABSTRACT: Pereira, LA, Freitas, TT, Zabaloy, S, Ferreira, RCA, Silva, ML, Azevedo, PHSM, and Loturco, I. Sprint and jump training on sand versus grass surfaces: effects on the physical performance of young soccer players. J Strength Cond Res 37(9): 1828-1833, 2023-The aims of this study were to (a) examine the effects of a 6-week sand training program including both sprint and jump exercises on the speed-related and vertical jump performance of elite young soccer players and (b) compare the changes induced by a sand training scheme with those induced by a similar training program (in volume, intensity, and exercise types) performed on grass. Twenty-four under-20 soccer players were randomly allocated to 2 training groups, as follows: "sand" ( n = 12) or "grass" ( n = 12) groups. Athletes performed squat and countermovement jumps, linear sprints, and Zigzag change-of-direction speed tests at pre-, mid- (after 6 training sessions), and postintervention (after 12 training sessions). Both groups exhibited similar increases in the vertical jump and Zigzag performance after the 6-week training period ( p values ranging from 0.0001 to 0.025; effect size ranging from 1.05 to 3.78, for main effect of time). No significant changes were detected for the linear sprint velocity for both the groups ( p values ranging from 0.079 to 1.00; effect size ranging from 0.07 to 0.65, for main effect of time). In summary, training on sand or grass surfaces resulted in similar improvements in the physical performance of elite young soccer players. This study confirms the current evidence on the effectiveness of both soft and harder training surfaces in improving the sprint and jump performance of team-sport athletes.

Does External Load Reflect Acute Neuromuscular Fatigue and Rating of Perceived Exertion in Elite Young Soccer Players?

ABSTRACT: Martínez-Serrano, A, Freitas, TT, Franquesa, X, Enrich, E, Mallol, M, and Alcaraz, PE. Does external load reflect acute neuromuscular fatigue and rating of perceived exertion in elite young soccer players? J Strength Cond Res 37(3): e1-e7, 2023-This study aimed to analyze the acute and residual effects of increased high-speed running (HSR) demands during an in-season training microcycle in young elite soccer players on localized neuromuscular fatigue (NMF) of the knee extensors (KE), posterior chain muscles, and rating of perceived exertion (RPE). Thirty-four elite young soccer players (age = 17.1 ± 0.8 years) were assessed in 2 consecutive days at different time points (baseline, POST-activation gym-based session, POST-small-sided game [SSG], POST-training 1 [TR1], POST-6H, POST-24H, POST-preventive gym-based session, and POST-training 2 [TR2]). Neuromuscular fatigue of the KE and posterior chain muscles was measured with a maximum voluntary isometric contraction (MVIC). External (total distance, number of accelerations or decelerations, and HSR distance) and internal (RPE) load was assessed during the SSG, TR1, and TR2 sessions. Players were divided through a median split, into "HIGH" or "LOW" group according to the training demands. The alpha level was set at p ≤ 0.05. A 2-way mixed effects model ANOVA showed a significant decreased in 90:20 MVIC after TR1 in the "HIGH" HSR group ( p = 0.037; effect size [ES] = 0.45). No significant differences in RPE were found after TR1 ( p = 0.637; ES = 0.58) and TR2 ( p = 0.109; ES = 0.62) when comparing the "HIGH" HSR group with the "LOW" HSR group. Assessing player's force production capabilities can be an effective strategy to detect NMF when HSR demands are acutely increased. Special caution should be taken when prescribing the training load of the training session based solely on RPE, as NMF might be present.

Biological maturation, contextual factors, and future career in basketball: A possible interrelationship?

This study aimed to analyse the relationship between the maturational state and contextual factors with future basketball career success in Under-16 (U16) Portuguese youth preparing for the U16 European Basketball Championships. Eighty-five Under-15 (U15) and U16 male basketball players (height: 189.7 ± 6.53 cm; body mass: 81.1 ± 9.96 kg; the age of peak height velocity: 13.3 ± 0.7 y) were selected by the Portuguese national coaching staff to participate in a national team training camp in 2016, 2017, and 2018 years. A binary logistic regression was employed to identify the influence of maturation, born quartile, demographic, geographic and economic characteristics, and sport career (i.e., drop out during first season and chance of playing professionally). Early maturing players were typically classified as inside players. Training experience and predicted adult height, and type of first club were able to predict players who dropped out during their first season at senior level (both p < 0.01). No variables were able to predict who played in a professional league during their first season at senior level. Practitioners should use these data to consider how national level basketball players are identified and developed, but also keep in mind of their specific contextual factors.

Load monitoring, strength training, and recovery in futsal: Practitioners' perspectives.

This study aimed to describe the current practices in futsal regarding a variety of topics related to performance and injury risk mitigation. Thirty-seven coaches from Spain and Portugal completed a questionnaire consisting of 28 closed questions organized in four categories: a) background information; b) training load (TL) monitoring and assessment of players' physical qualities; c) strength training (ST) practices; and d) recovery (REC) methods. The results showed that coaches varied in experience (1-8 years) and age (from 20 years to >50 years). Overall, 97.3% of the participants declared monitoring TL, with rating of perceived exertion, heart rate monitors, and wearable technology being used by 86.5%, 40.5%, and 37.8%, respectively. Neuromuscular and strength testing are the most common practices to evaluate performance and fatigue during the season. ST is a significant component of futsal, being performed 3 times/week during the pre- and in-season. ST is prescribed via %1RM - XRM (59.5%), velocity-based training (21.7%), repetitions in reserve (18.9%), until failure (10.8%), and circuit training (2.7%). 'Better Monitoring', 'More Individualized', 'Better Facilities', 'More Staff', and 'More Time' were the main aspects to improve ST. Multiple post-match REC strategies are used, with durations ranging from 0-15 to 16-30 min independently of game location.

Changes in body composition and physical performance measures during a regular competitive season among young backs and forwards rugby players.

This study aimed to compare the changes in body composition and physical qualities of under 19's backs and forwards during the season (i.e. from pre-season [Pre-S] to end-season [End-S]). Twenty-seven male youth rugby union players (mean ± SD: age, Forwards [n = 11]: 17.5 ± 1.2 and Backs [n = 16]: 17.0 ± 0.9 years) participated in this study. Participants were tested twice (i.e. at Pre-S and End-S) and completed: anthropometric, body composition, countermovement and squat jumps, 30-m sprint, squat and bench press 1-repetition maximum (SQ-1RM and BP-1RM). Significant differences were observed between Pre-S and End-S for body mass (BM) and lean mass (LM), among both playing positions (p < 0.034; ES > 0.71), whereas all other variables remained unchanged. Regarding physical performance, backs and forwards showed greater SQ-1RM and BP-1RM, respectively (p < 0.043; ES>-0.69). Moreover, backs and forwards exhibited higher split times from 5 to 30 m (p: 0.013 to <0.001). Substantial increases were observed in BM and LM for backs and forwards, which may have negatively impacted acceleration (i.e. 5-m sprint time) and initial sprint momentum for both playing positions. Our findings highlight the importance of carefully balancing changes in BM and body composition, to avoiding the detrimental effects of these variations on sprint performance.

Squat and countermovement jump performance across a range of loads: a comparison between Smith machine and free weight execution modes in elite sprinters.

The aims of this study were to: 1) provide and compare the height achieved during Smith machine (SM) and free weight (FW) loaded jumps executed over a wide spectrum of loads (40-120% of body mass [BM]); and 2) test the difference between loaded and unloaded squat jump (SJ) and countermovement jump (CMJ) attempts in ten highly trained male sprinters. On the first visit, athletes performed unloaded SJ and CMJ, loaded SJ with loads corresponding to 40, 60, 80, 100, and 120% BM, and loaded CMJ at 100% BM using an Olympic barbell (FW). On the second visit, they performed loaded SJ and CMJ tests under the same loading conditions on the SM device and, subsequently, a half-squat one-repetition maximum (1RM) assessment. The relative strength (RS = 1RM/BM) of the athletes was 2.54 ± 0.15. Loaded SJ performance was similar between SM and FW, and across all loading conditions. Differences in favour of CMJ (higher jump heights compared with SJ) were superior in the unloaded condition but decreased progressively as a function of loading. In summary, sprinters achieved similar SJ heights across a comprehensive range of loads, regardless of the execution mode (FW or SM). The positive effect of the countermovement on jump performance is progressively reduced with increasing load.