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.

Traditional Free-Weight Vs. Variable Resistance Training Applied to Elite Young Soccer Players During a Short Preseason: Effects on Strength, Speed, and Power Performance.

ABSTRACT: Loturco, I, Pereira, LA, Reis, VP, Zanetti, V, Bishop, C, and Mcguigan, MR. Traditional free-weight vs. variable resistance training applied to elite young soccer players during a short preseason: Effects on strength, speed, and power performance. J Strength Cond Res 36(12): 3432-3439, 2022-Maximizing the neuromuscular capacities of players is a critical challenge during short soccer preseasons. This study compared the effects of 2 strength-power training regimes, on the strength, speed, and power performance of elite young soccer players during a 4-week preseason. Twenty-five under-20 players from the same club were pair matched in 2 training groups as follows: traditional training group (TTG) ( n = 13), athletes performed half-squat (HS) and jump-squat (JS) exercises as traditionally prescribed, and elastic band (EB) group (EBG) ( n = 12), athletes performed HS and JS with EB attached to the barbell. Vertical jump height, 20-m sprint velocity, change of direction (COD) speed, HS and JS power, and 1 repetition maximum (1RM) in the HS were assessed before, after 2-week, and after 4-week of training. A two-way analysis of variance with repeated measures was used to assess the effects of both training protocols over the experimental period. Both strategies were effective for significantly improving HS and JS power (effect sizes [ESs] = 1.00-1.77), HS 1RM (ES = 1.68 and 1.51 for TTG and EBG, respectively), vertical jumping ability (ES = 0.37-0.65), and COD speed (ES = 0.81 and 0.39 for TTG and EBG, respectively), when comparing premeasures and postmeasures. By contrast, both TTG and EBG failed to increase 20-m sprint velocity (ES ranging between -0.54 and 0.23). In conclusion, both training schemes were able to improve the strength and power performance but not the sprint capacity of young soccer players. To accelerate strength gains over very-short time periods (i.e., 2 weeks), variable resistance training may be advantageous. Conversely, to optimize power adaptations in ballistic exercises across a similar time period, traditional free-weight training may be preferred.

Change of Direction Performance in Elite Players From Different Team Sports.

ABSTRACT: Loturco, I, Pereira, LA, Reis, VP, Abad, CCC, Freitas, TT, Azevedo, PHSM and Nimphius, S. Change of direction performance in elite players from different team sports. J Strength Cond Res 36(3): 862-866, 2022-The primary aim of this study was to examine the differences in change of direction (COD) deficit between elite futsal, soccer, handball, and rugby players. A secondary aim was to compare the performance in both COD and linear speed tests among these athletes. One-hundred sixty-one elite male players from 4 team sports performed a 20-m linear sprint speed and a Zigzag COD speed test. The COD deficit was calculated as the difference between linear and Zigzag test velocities. Differences in COD speed, COD deficit, and sprint velocity were assessed via 1-way analysis of variance. The significance level was set at p < 0.05. Soccer players displayed significantly lower performance than the remaining team sports, and rugby players performed better than all the other groups in the Zigzag COD test. Moreover, the COD deficit was significantly higher in soccer players in comparison with the other disciplines (p < 0.05). No differences were observed in the COD deficit among rugby, futsal, and handball players (p > 0.05). In summary, soccer players were slower than futsal, handball, and rugby players to change direction and presented the greatest COD deficit magnitude. By contrast, the fastest athletes in the COD speed test (rugby players) were not more effective than futsal and handball players at changing direction (as they exhibited similar levels of COD deficit). Coaches should be aware of this evidence, which reinforces previous findings, indicating that very specialized training strategies might be required to improve COD performance in professional athletes.

Acute Effects of Progressive Sled Loading on Resisted Sprint Performance and Kinematics.

ABSTRACT: 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.

Impact of Sled Loads on Performance and Kinematics of Elite Sprinters and Rugby Players.

PURPOSE: To examine the changes in resisted sprint performance and kinematics provoked by different sled loads in elite sprinters and rugby players. METHODS: Eight elite male sprinters and 10 rugby union players performed 20-m sprints under 3 loading conditions (0%, 20%, and 60% body mass [BM]). Sprint time was measured in 0 to 5, 5 to 10, and 10 to 20 m, while stride length and hip, knee, and ankle angles were measured using an 8-sensor motion analysis system at the same distances. RESULTS: Sprinters were significantly faster than rugby players in unresisted and resisted sprints using 20% BM (effect size, "ES" [90% confidence limit, CL] range: 0.65 [0.03 to 1.27]; 3.95 [3.10 to 4.81]), but these differences were not significant at 60% BM. Compared to rugby players, sprinters showed lower velocity decrement in resisted sprints using 20% BM (ES [90% CL] range: 0.75 [0.06 to 1.44]; 2.43 [0.83 to 4.02], but higher velocity decrement using 60% BM (ES [90% CL] range: 1.13 [0.43 to 1.82]; 1.46 [0.81 to 2.11]). No significant differences were detected in stride length between sprinters and rugby players for any sprint condition (ES [90% CL] range: 0.02 [-0.72 to 0.76]; 0.84 [0.13 to 1.54]). Rugby players showed higher hip flexion in resisted sprints (ES [90% CL] range: 0.30 [-0.54 to 1.14]; 1.17 [0.20 to 2.15]) and lower plantar flexion in both unresisted and resisted sprints (ES [90% CL] range: 0.78 [0.18 to 1.38]; 1.69 [1.00 to 2.38] than sprinters. CONCLUSIONS: The alterations induced by resisted sprints in sprint velocity and running technique differed between sprinters and rugby players. Some caution should be taken with general sled loads prescriptions, especially when relative loads are based on distinct percentages of BM, as training responses vary among sports and individuals.

Correlations between jump measures and competitive performance remain stable over time in top-level sprinters.

BACKGROUND: We examined the relationships between jump performance measures, sprint tests, and 100-m competition times in 11 top-level sprinters during two successive competitive 4-week mesocycles. METHODS: Physical tests were performed 7-12 days before 3 sequential competitions. Sprinters completed standing long jump, squat and countermovement jumps, and 60-m sprint tests on each occasion. A repeated measures analysis of variance was used to compare the physical assessments and actual competition results among the three moments. A Pearson product-moment correlation coefficient was used to analyze the relationships between the multiple variables over the consecutive mesocycles. Significance level was set at P<0.05. RESULTS: No significant differences were observed among the periods for any jump or sprint performance measure (ES ranging from 0.02 to 0.33; P>0.05). Very large to nearly perfect correlations were observed for all sprint and jump variables and 100-m dash times in the three moments analyzed (P<0.05). CONCLUSIONS: Our data indicate that simple jump measures can be prospectively used to monitor sprint performance. Notably, the standing long jump test was the most consistently related to 100-m time. This simple strategy may help track and field coaches to better adjust the competitive approach of their sprinters, thus optimizing their peak performance.

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.

Variations in the Physical Performance of Olympic Boxers over a Four-Day National Qualifying Tournament.

The aim of this study was to examine changes in body mass (BM) and power-related measures in Olympic boxers during an official qualifying boxing tournament. Fourteen elite amateur boxers from the Brazilian National Team (eight men and six women) participated in this study. Athletes performed three fights in four days against the same opponent of the same weight-category. Before and immediately after every fight, BM, countermovement jump (CMJ) height, and power production in the bench-press and half-squat exercises were assessed in the same order and on the same time of the day. A two-way repeated-measures ANOVA with the Bonferroni post-hoc analysis was used to determine the variations between pre- and post-measures. The statistical significance was set as p < 0.05. The athletes were able to maintain their baseline weight and physical performance throughout the experimental period, as shown by the lack of significant changes in BM, CMJ height, and upper- and lower-limb power output. Throughout a four-day qualifying tournament, the BM and power-related performance of Olympic boxers were not affected either by match execution or by successive matches. As scoring actions are highly dependent on muscle power, it is likely that these combat athletes are able to maintain optimal levels of performance across consecutive matches.

Effects of a Congested Fixture Period on Speed and Power Performance of Elite Young Soccer Players.

PURPOSE: To investigate the effects of a match-congested period on straight and curve sprint performance, change of direction (COD) speed and deficit, vertical jumping ability, and half-squat (HS) mean propulsive power (MPP) output in young soccer players. METHODS: A total of 15 under-20 elite male soccer players participated in 14 matches over 8 weeks. The following assessments were performed before and after the congested fixture period: squat and countermovement jumps, 17-m linear sprint, curve sprint test for the "good" (CSGS) and "weak" (CSWS) sides, modified 17-m Zigzag test, and HS MPP. Magnitude-based inferences and a paired t test were used to analyze pre-post changes in the assessed variables. RESULTS: Very likely (P < .05) decreases were noticed in 17-m sprint velocity (effect size [ES] [90% confidence limit; CL], -0.56 [-0.32 to -0.81]) and CSGS (ES [90% CL], -0.72 [-0.40 to 1.03]) after the 8-week period. A possible but nonsignificant impairment was revealed in CSWS (ES [90% CL], -0.18 [0.03 to -0.39]), and countermovement jump (ES [90% CL], -0.21 [-0.54 to 0.12]). Zigzag velocity (ES [90% CL], -2.90 [-2.45 to -3.36]) and COD deficit (ES [90% CL], 0.86 [0.52 to 1.20]) were almost certainly and significantly (P < .05) reduced and increased, respectively, after the match-congested period. An almost certain and significant (P < .05) reduction was found in HS MPP (ES [90% CL], -1.18 [-0.76 to -1.61]). CONCLUSIONS: Straight and curve sprint velocity, COD speed and deficit, and HS MPP were impaired after the match-congested period. Vertical jump height was possibly decreased. Seasonal phases comprising high volumes of soccer-specific training and competition seem to be detrimental to speed-power qualities in under-20 elite soccer players.

Multidirectional sprints in soccer: are there connections between linear, curved, and change-of-direction speed performances?

BACKGROUND: The aim of this study was to investigate the relationships between linear sprint, curve sprint (CS) and change of direction (COD) abilities and vertical jump performance in elite young soccer players. METHODS: Twenty-nine players from the same soccer club participated in this study. On the same day, athletes performed countermovement jump (CMJ), 17-m linear sprint (with a 10-m split time), CS (for both sides) and COD tests. A Pearson product moment correlation was performed to determine the associations between the assessed variables. Significance level was set at P<0.05. RESULTS: Linear sprint was significantly related to CS (r ranging from 0.67 and 0.76; P<0.05) but not to COD performance (r=0.23 and 0.33 for 10- and 17-m, respectively; P>0.05). CS ability (for both good and weak sides) was significantly associated with COD performance (r=0.60 and 0.54, respectively; P<0.05). CMJ height was significantly correlated with both linear and CS velocities (r varying between 0.50 and 0.68; P<0.05), but not with COD velocity (r=0.37; P>0.05). CONCLUSIONS: Based on these findings, it is possible to suggest that training strategies designed to improve vertical jumping capacity may potentially improve both linear and curvilinear sprint abilities. Moreover, increases in COD velocity may also produce positive changes in CS performance.

Transference Effect of Short-Term Optimum Power Load Training on the Punching Impact of Elite Boxers.

ABSTRACT: Loturco, I, Pereira, LA, Kobal, R, Fernandes, V, Reis, VP, Romano, F, Alves, M, Freitas, TT, and McGuigan, M. Transference effect of short-term optimum power load training on the punching impact of elite boxers. J Strength Cond Res 35(9): 2373-2378, 2021-This study examined the changes in bench press (BP), jump squat (JS), and half-squat (HS) power outputs induced by a short-term (1 week) training scheme based on the optimum power load (OPL) applied to national boxing athletes and measured the transference effect coefficient (TEC) of these exercises on punching impact. Eight elite boxing athletes from the Brazilian National team participated in this study. Athletes were tested before and after 3 power-oriented training sessions performed at the OPL. The physical assessments comprised punching impact measures (jabs and crosses) at fixed and self-selected distances, and bar-power output in BP, HS, and JS exercises. Magnitude-based differences were used to compare pre-training and post-training sessions. Transference effect coefficient was calculated as the ratio between the result gain in the "untrained exercises" (punching impact in jabs and crosses) and "trained exercises" (HS, JS, and BP), for variables presenting an effect size of at least 0.2. The OPL training elicited meaningful increases in the punching impact forces (∼8%) and in both JS and HS power outputs (∼12 and ∼14%, respectively), but not in BP power output. There was an effective transference (TEC = ∼0.80) of JS and HS performance gains to punching impact force, suggesting that increases in lower-limb power can be directly transferred to punching impact. These results provide coaches and practitioners with valuable information about how to rapidly and effectively increase the punching impact force of elite amateur boxers.

Differences in Change of Direction Speed and Deficit Between Male and Female National Rugby Sevens Players.

ABSTRACT: Freitas, TT, Alcaraz, PE, Calleja-González, J, Arruda, AFS, Guerriero, A, Kobal, R, Reis, VP, Pereira, LA, and Loturco, I. Differences in change of direction speed and deficit between male and female national rugby sevens players. J Strength Cond Res 35(11): 3170-3176, 2021-The aims of this study were to assess the change of direction (COD) deficit in different tasks and to investigate the differences in COD ability and COD deficit between male and female rugby sevens players. Thirty-six elite rugby players from the Brazilian National senior sevens teams (18 males and 18 females) completed the following physical assessments: squat and countermovement jumps; drop jump from a 45-cm height; horizontal single and triple jumps; 40-m linear sprint; Pro-agility, L-drill, and Zig-zag COD tests; and 1 repetition maximum test in the squat exercise. The differences between male and female performances were determined using magnitude-based inferences, an independent t test, and effect sizes (ES). Pearson's product-moment correlations were performed to determine the relationships among the different COD velocities and COD deficits. Men demonstrated likely to almost certainly significantly higher performances than women in all speed-power assessments and COD tasks (ES ranging from 0.61 to 2.09; p < 0.05), with the exception of the Zig-zag drill (ES = 0.24; p > 0.05). Furthermore, males displayed significantly greater COD deficits in all tests and higher sprint momentum (ES ranging from 0.78 to 2.95; p < 0.05). Large significant relationships among COD velocities (r ranging from 0.71 to 0.88; p < 0.05) and almost perfect significant correlations among all COD deficits (r ranging from 0.90 to 0.95; p < 0.05) were obtained in both sexes. The present results indicate that male rugby players are less efficient at changing direction, relative to their maximum sprint velocity. In addition, the correlations between the different COD deficits and COD speeds suggest that elite rugby players demonstrate similar ability to change direction, independently of the angle of directional change. From a practical perspective, this implies that a more comprehensive training strategy including eccentric exercises, acceleration-deceleration drills, and directional change technique is warranted to improve the COD ability (and reduce the COD deficit) of faster and more powerful rugby sevens players.

Relationship Between Power Output and Speed-Related Performance in Brazilian Wheelchair Basketball Players.

This study aimed to investigate the association between the optimum power load in the bench press (BP), shoulder press (SP), and prone bench pull (PBP) exercises and acceleration (ACC) and speed performances in 11 National Team wheelchair basketball (WB) players with similar levels of disability. All athletes were previously familiarized with the testing procedures that were performed on the same day during the competitive period of the season. First, athletes performed a wheelchair 20-m sprint assessment and, subsequently, a maximum power load test to determine the mean propulsive power (MPP) in the BP, SP, and PBP. A Pearson product-moment correlation was used to examine the relationships between sprint velocity (VEL), ACC, and the MPP in the three exercises. The significance level was set as p < .05. Large to very large significant associations were observed between VEL and ACC and the MPP in the BP, SP, and PBP exercises (r varying from .60 to .77; p < .05). The results reveal that WB players who produce more power in these three exercises are also able to accelerate faster and achieve higher speeds over short distances. Given the key importance of high and successive ACCs during wheelchair game-related maneuvers, it is recommended that coaches frequently assess the optimum power load in BP, SP, and PBP in WB players, even during their regular training sessions.

Curve sprinting in soccer: relationship with linear sprints and vertical jump performance.

We examined the relationships among linear speed, vertical jumping ability and curve sprint (CS) performance. Moreover, the correlations between linear and curvilinear sprint velocities and CS deficit were tested. Twenty-eight under-20 soccer players performed squat and countermovement jumps, 17-m linear sprint (with split times at 5 and 10 m), and a CS test for both sides. For the first time, the new proposed CS deficit was calculated as the difference between 17-m velocity and CS test velocity. Pearson's product moment of correlation was performed to determine the relationships among the distinct variables tested. Significance level was set at P < 0.05. Large to very large relationships between linear sprint speed and CS performance were observed, on both the "good" and "weak" sides. In addition, moderate to large correlations between linear and curve sprint abilities and vertical jumps were found. Finally, the CS deficit was negatively associated with the CS good side performance. Linear sprint and CS velocities for both good and weak sides were closely related. The CS deficit was only related to the CS weak side performance, and the vertical jumping ability was significantly associated with both linear and curvilinear sprint velocities. The present results suggest that training methods capable of improving linear sprint and vertical jumping abilities may also improve CS performance.

Resisted Sprint Velocity in Female Soccer Players: Influence of Physical Capacities.

This study aimed to examine the effects of different sled overloads on maximum sprint velocity achieved by female soccer players with different strength, speed, and power levels. Twenty elite female soccer players from the same club participated. On the same day, athletes performed: linear and resisted-sprint tests with 30 and 60 % of body-mass over 5-, 10-, and 20-m; half-squat maximum bar-power output, and half-squat one-repetition maximum assessment. A median split analysis was used to divide players into two groups according to their velocity, half-squat one-repetition maximum, and half-squat power. Differences in percentage decreases between unresisted- and resisted-sprints comparing higher and lower groups were analyzed using magnitude-based inferences. Overall, the stronger, faster, and more powerful players were less affected by both loads, as demonstrated by their lower decreases in velocity over the different distances. However, half-squat power appeared to be more sensitive for indicating impairments in resisted-sprint performance, due to meaningful differences in percentage decreases observed between higher and lower power groups. Notably, overloads of 30 and 60% of body-mass provoked substantial reductions in resisted-sprint velocity (~22.9% for 30% and ~51.4% for 60% of body-mass, relative to unresisted-sprint velocity). Athletes with superior power levels are less affected by the progressive sled overloading.

Effects of Drop Jumps on 1000-m Performance Time and Pacing in Elite Male and Female Endurance Runners.

PURPOSE: To evaluate the effect of drop jumps (DJs) on performance time and pacing in a field test (ie, 1000 m) commonly used to evaluate endurance runners and to evaluate running and jumping performance in male and female athletes separately. METHODS: Twenty elite endurance runners (male, n = 10, 27.8 [7.0] y, 62.3 [5.2] kg; female, n = 10, 25.9 [5.3] y, 51.7 [4.1] kg) competing in middle- and long-distance events participated in this study. After determination of the box height associated with the best reactive strength index, athletes randomly performed a warm-up with or without the inclusion of 5 DJs with the highest reactive strength index prior to a 1000-m track test. Performance time and pacing (250-m splits) were determined. Countermovement-jump heights at different time points and blood lactate concentration after running tests were also recorded. RESULTS: A "possible" faster 1000-m time (162.4 vs 165.3 s) with a "very likely" faster first split (38.8 vs 40.3 s) was observed in male athletes in the DJ condition. In contrast, female athletes showed a "possible" slower running time (186.8 vs 184.8 s) and a "likely" greater blood lactate concentration after the 1000-m test in the DJ condition. Male and female athletes presented greater countermovement-jump performances after warm-up and running tests in both conditions. CONCLUSIONS: The inclusion of 5 DJs with the height associated with the best reactive strength index induced a "possible" improvement in 1000-m performance time in elite male endurance runners. The current protocol should be avoided in female athletes.

Power training in elite young soccer players: Effects of using loads above or below the optimum power zone.

This study aimed to examine the effects of two jump squat (JS) training programs involving different loading ranges in under-20 soccer players during a preseason period. Twenty-three elite young soccer players performed sprint speed (at 5-, 10-, and 20-m), change-of-direction (COD) speed, JS peak-power (PP), and countermovement jump (CMJ) tests pre and post four weeks of training. Athletes were pair-matched in two groups according to their optimum power loads (OPL) as follows: lower than OPL (LOPL; athletes who trained at a load 20% lower than the OPL) and higher than OPL (HOPL; athletes who trained at a load 20% higher than the OPL). Magnitude-based inferences were used to compare pre- and post-training measures. Meaningful increases in the PP JS were observed for both groups. Likely and possible improvements were observed in the 5- and 10-m sprint velocity in the LOPL group. Meanwhile, possible and likely improvements were observed in the CMJ, 5- and 10-m sprint velocity, and COD speed in the HOPL group. Overall, both training schemes induced positive changes in athletic performance. Soccer coaches and sport scientists can implement the JS OPL-based training schemes presented here, either separately or combined, to improve the physical performance of youth soccer players.

Comparing the magnitude and direction of asymmetry during the squat, countermovement and drop jump tests in elite youth female soccer players.

The aims of the present study were to provide an in-depth comparison of inter-limb asymmetry and determine how consistently asymmetry favours the same limb during different vertical jump tests. Eighteen elite female under-17 soccer players conducted unilateral squat jumps (SJ), countermovement jumps (CMJ) and drop jumps (DJ) on a portable force platform, with jump height, peak force, concentric impulse and peak power as common metrics across tests. For the magnitude of asymmetry, concentric impulse was significantly greater during the SJ test compared to CMJ (p = 0.019) and DJ (p = 0.003). No other significant differences in magnitude were present. For the direction of asymmetry, Kappa coefficients revealed fair to substantial levels of agreement between the SJ and CMJ (Kappa = 0.35 to 0.61) tests, but only slight to fair levels of agreement between the SJ and DJ (Kappa = -0.26 to 0.18) and CMJ and DJ (Kappa = -0.13 to 0.26) tests. These results highlight that the mean asymmetry value may be a poor indicator of true variability of between-limb differences in healthy athletes. The direction of asymmetry may provide a useful monitoring tool for practitioners in healthy athletes, when no obvious between-limb deficit exists.

Change of Direction Deficit in National Team Rugby Union Players: Is There an Influence of Playing Position?

The aim of this study was to investigate the change of direction (COD) ability and deficits of elite rugby union players, discriminating between position (backs and forwards), and between "faster and slower players", in multiple COD tasks. Twenty-four male rugby union players from the Brazilian senior National team completed the following assessments: Squat and countermovement jumps; drop jump; standing long jump, horizontal triple jumps; 40-m linear sprint; Pro-agility, L-Drill, and Zig-zag COD tests; and squat 1-repetition maximum. The differences between backs and forwards and between faster and slower performers were examined using magnitude-based inferences. Backs were faster (in both linear and COD speed tests) and jumped higher than forwards. Moreover, they generated an inferior sprint momentum. No differences were found in COD deficit between playing positions. However, when dividing the sample by median split, faster players outperformed their slower counterparts in all power⁻speed variables and presented higher COD deficits. These results suggest that separating rugby players by playing position might not discriminate players with different COD skills and that the median split analysis is more sensitive to identifying these differences. Furthermore, the present data indicate that faster rugby players are less efficient at changing direction and tolerating higher approach velocities in COD maneuvers.