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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]

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. [ABSTRACT FROM AUTHOR]

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]

BACKGROUND: This study examined the differences in physical and anthropometric traits between specific playing positions (i.e., forwards: front row, second row, back row; backs: half backs, centers, wings/fullbacks) in amateur rugby players and analyzed the magnitude of correlations among jump, sprint, and strength measures in forwards and backs. METHOD: Sixty-four male rugby players were assessed in anthropometrics, a variety of vertical jumps, 10- and 30-m sprint, and strength tests (i.e., squat and bench press). RESULTS: Front row forwards (F FR) demonstrated significantly higher body mass (BM) than second row (F SR) and back row (F BR) (107.4 ± 12.8, 99.1 ± 9.9 and 91.6 ± 7.6 kg respectively; p < 0.001). F FR showed greater absolute strength in bench press and squat, although no differences were found in relative strength. Regarding the differences in jump performance, F BR and F SR showed significantly (p < 0.05) and significant to non-significant (p = 0.042–0.078, ES = 0.90–1.55) higher jumps in all tasks compared to F FR. Moreover, F BR demonstrated lower sprint times and greater maximum sprinting speed (MSS) than F FR (p < 0.01). For the backs, centers (B CEN) were significantly heavier (p < 0.05) and exhibited a non-significantly moderate larger sprint momentum (p = 0.068, ES = 0.75) compared to half backs (B HB). MSS values were small to moderately greater in favor of wings/fullbacks [B WFB ] (p = 0.188–0.059, ES = 0.50–0.71). Finally, statistically significant correlations were found between drop jump (flight time) and jump height across all jump tasks, sprint times and speed for both forwards (r = 0.541 to 0.996, p < 0.001) and backs (r = 0.422 to 0.995, p < 0.05). CONCLUSIONS: In conclusion, F FR demonstrated significant, small to very large differences, when compared to their specific peers, whereas the backs were more similar. Additionally, our results indicated moderate to strong associations between explosive tasks such as sprinting and jumping in both playing positions. [ABSTRACT FROM AUTHOR]

BACKGROUND: The use of force-velocity imbalance (Fvimb) has been proposed as an effective method for prescribing training loads aiming to enhance physical performance. OBJECTIVE: This study aimed to analyse the effects on lower body strength, jump and sprint performance of different individualised resistance training (RT) programmes based on Fvimb in mgby players. METHODS: Thirty-four senior rugby players were divided into four groups according to their Fvimb: Not individualised (NI, n = 8), velocity imbalance (Vimb, n = 6), force imbalance (Fimb, n = 11) and well balanced (WB, n = 9). The intervention period consisted of a 7-week resistance, plyometric and sprint training programme performed twice a week. Pre- and Post-training measures included Force-velocity (Fv) profile, countermovement jump (CMJ), 30 m sprint test and estimated one-repetition maximum in squat (1RM-SQ). RESULTS: Significant "group" x "time" interactions (P < 0.05) were observed for theoretical maximal velocity (V0), theoretical maximal force (F0), and Fvimb. No significant "group" x "time" interactions were observed for the rest of variables analysed. The Vimb group significantly (P < 0.05) increased V0, whereas decreased F0 and Fvimb. The Fimb group showed significant (P < 0.05) decreases in V0, whereas increased F0 and Fvimb. The WB and Nl groups did not show significant changes in these parameters. The WB group induced significant enhancements in 10 m, 20 m, and 30 m sprint times, maximum sprint speed and sprint momentum (SM), whereas Fimb attained significant changes in 20 m and 30 m sprint times. The NI group attained significant improvements (P < 0.05) in SM. No significant changes were observed for 1RM-SQ and jump performance. CONCLUSION: Individualised RT programs based on Fvimb induced improvements in sprint performance. Moreover, individualised RT programs based on Fvimb induced better adjustments of the Fv profile to the theoretical "optimal" Fv profile, although any group improved SQ strength, jump height or maximum power. [ABSTRACT FROM AUTHOR]