TY - GEN A1 - Nobari, Hadi A1 - Mahmoudzadeh Khalili, Sara A1 - Denche Zamorano, Angel Manuel A1 - ‪Bowman, ‪Thomas G. A1 - Granacher, Urs T1 - Workload is associated with the occurrence of non-contact injuries in professional male soccer players: A pilot study T2 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Injuries in professional soccer are a significant concern for teams, and they are caused amongst others by high training load. This cohort study describes the relationship between workload parameters and the occurrence of non-contact injuries, during weeks with high and low workload in professional soccer players throughout the season. Twenty-one professional soccer players aged 28.3 ± 3.9 yrs. who competed in the Iranian Persian Gulf Pro League participated in this 48-week study. The external load was monitored using global positioning system (GPS, GPSPORTS Systems Pty Ltd) and the type of injury was documented daily by the team's medical staff. Odds ratio (OR) and relative risk (RR) were calculated for non-contact injuries for high- and low-load weeks according to acute (AW), chronic (CW), acute to chronic workload ratio (ACWR), and AW variation (Δ-Acute) values. By using Poisson distribution, the interval between previous and new injuries were estimated. Overall, 12 non-contact injuries occurred during high load and 9 during low load weeks. Based on the variables ACWR and Δ-AW, there was a significantly increased risk of sustaining non-contact injuries (p < 0.05) during high-load weeks for ACWR (OR: 4.67), and Δ-AW (OR: 4.07). Finally, the expected time between injuries was significantly shorter in high load weeks for ACWR [1.25 vs. 3.33, rate ratio time (RRT)] and Δ-AW (1.33 vs. 3.45, RRT) respectively, compared to low load weeks. The risk of sustaining injuries was significantly larger during high workload weeks for ACWR, and Δ-AW compared with low workload weeks. The observed high OR in high load weeks indicate that there is a significant relationship between workload and occurrence of non-contact injuries. The predicted time to new injuries is shorter in high load weeks compared to low load weeks. Therefore, the frequency of injuries is higher during high load weeks for ACWR and Δ-AW. ACWR and Δ-AW appear to be good indicators for estimating the injury risk, and the time interval between injuries. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 784 KW - ACWR KW - external load KW - football KW - prevention KW - performance KW - injury risk Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-562216 SN - 1866-8364 SP - 1 EP - 9 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Nobari, Hadi A1 - Mahmoudzadeh Khalili, Sara A1 - Denche Zamorano, Angel Manuel A1 - Bowman, ‪Thomas G. A1 - Granacher, Urs T1 - Workload is associated with the occurrence of non-contact injuries in professional male soccer players: A pilot study JF - Frontiers in Psychology N2 - Injuries in professional soccer are a significant concern for teams, and they are caused amongst others by high training load. This cohort study describes the relationship between workload parameters and the occurrence of non-contact injuries, during weeks with high and low workload in professional soccer players throughout the season. Twenty-one professional soccer players aged 28.3 ± 3.9 yrs. who competed in the Iranian Persian Gulf Pro League participated in this 48-week study. The external load was monitored using global positioning system (GPS, GPSPORTS Systems Pty Ltd) and the type of injury was documented daily by the team's medical staff. Odds ratio (OR) and relative risk (RR) were calculated for non-contact injuries for high- and low-load weeks according to acute (AW), chronic (CW), acute to chronic workload ratio (ACWR), and AW variation (Δ-Acute) values. By using Poisson distribution, the interval between previous and new injuries were estimated. Overall, 12 non-contact injuries occurred during high load and 9 during low load weeks. Based on the variables ACWR and Δ-AW, there was a significantly increased risk of sustaining non-contact injuries (p < 0.05) during high-load weeks for ACWR (OR: 4.67), and Δ-AW (OR: 4.07). Finally, the expected time between injuries was significantly shorter in high load weeks for ACWR [1.25 vs. 3.33, rate ratio time (RRT)] and Δ-AW (1.33 vs. 3.45, RRT) respectively, compared to low load weeks. The risk of sustaining injuries was significantly larger during high workload weeks for ACWR, and Δ-AW compared with low workload weeks. The observed high OR in high load weeks indicate that there is a significant relationship between workload and occurrence of non-contact injuries. The predicted time to new injuries is shorter in high load weeks compared to low load weeks. Therefore, the frequency of injuries is higher during high load weeks for ACWR and Δ-AW. ACWR and Δ-AW appear to be good indicators for estimating the injury risk, and the time interval between injuries. KW - ACWR KW - external load KW - football KW - prevention KW - performance KW - injury risk Y1 - 2022 U6 - https://doi.org/10.3389/fpsyg.2022.925722 SN - 1664-1078 SP - 1 EP - 9 PB - Frontiers CY - Lausanne, Schweiz ER - TY - GEN A1 - Ramirez-Campillo, Rodrigo A1 - Moran, Jason A1 - Oliver, Jonathan L. A1 - Pedley, Jason S. A1 - Lloyd, Rhodri S. A1 - Granacher, Urs T1 - Programming Plyometric-Jump Training in Soccer: A Review T2 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe N2 - The aim of this review was to describe and summarize the scientific literature on programming parameters related to jump or plyometric training in male and female soccer players of different ages and fitness levels. A literature search was conducted in the electronic databases PubMed, Web of Science and Scopus using keywords related to the main topic of this study (e.g., “ballistic” and “plyometric”). According to the PICOS framework, the population for the review was restricted to soccer players, involved in jump or plyometric training. Among 7556 identified studies, 90 were eligible for inclusion. Only 12 studies were found for females. Most studies (n = 52) were conducted with youth male players. Moreover, only 35 studies determined the effectiveness of a given jump training programming factor. Based on the limited available research, it seems that a dose of 7 weeks (1–2 sessions per week), with ~80 jumps (specific of combined types) per session, using near-maximal or maximal intensity, with adequate recovery between repetitions (<15 s), sets (≥30 s) and sessions (≥24–48 h), using progressive overload and taper strategies, using appropriate surfaces (e.g., grass), and applied in a well-rested state, when combined with other training methods, would increase the outcome of effective and safe plyometric-jump training interventions aimed at improving soccer players physical fitness. In conclusion, jump training is an effective and easy-to-administer training approach for youth, adult, male and female soccer players. However, optimal programming for plyometric-jump training in soccer is yet to be determined in future research. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 813 KW - human physical conditioning KW - exercise KW - resistance training KW - muscle strength KW - plyometric exercise KW - musculoskeletal and neural physiological phenomena KW - movement KW - sports KW - football KW - youth sport Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-581031 SN - 1866-8364 IS - 813 ER - TY - JOUR A1 - Ramirez-Campillo, Rodrigo A1 - Moran, Jason A1 - Oliver, Jonathan L. A1 - Pedley, Jason S. A1 - Lloyd, Rhodri S. A1 - Granacher, Urs T1 - Programming Plyometric-Jump Training in Soccer: A Review JF - Sports N2 - The aim of this review was to describe and summarize the scientific literature on programming parameters related to jump or plyometric training in male and female soccer players of different ages and fitness levels. A literature search was conducted in the electronic databases PubMed, Web of Science and Scopus using keywords related to the main topic of this study (e.g., “ballistic” and “plyometric”). According to the PICOS framework, the population for the review was restricted to soccer players, involved in jump or plyometric training. Among 7556 identified studies, 90 were eligible for inclusion. Only 12 studies were found for females. Most studies (n = 52) were conducted with youth male players. Moreover, only 35 studies determined the effectiveness of a given jump training programming factor. Based on the limited available research, it seems that a dose of 7 weeks (1–2 sessions per week), with ~80 jumps (specific of combined types) per session, using near-maximal or maximal intensity, with adequate recovery between repetitions (<15 s), sets (≥30 s) and sessions (≥24–48 h), using progressive overload and taper strategies, using appropriate surfaces (e.g., grass), and applied in a well-rested state, when combined with other training methods, would increase the outcome of effective and safe plyometric-jump training interventions aimed at improving soccer players physical fitness. In conclusion, jump training is an effective and easy-to-administer training approach for youth, adult, male and female soccer players. However, optimal programming for plyometric-jump training in soccer is yet to be determined in future research. KW - human physical conditioning KW - exercise KW - resistance training KW - muscle strength KW - plyometric exercise KW - musculoskeletal and neural physiological phenomena KW - movement KW - sports KW - football KW - youth sport Y1 - 2022 U6 - https://doi.org/10.3390/sports10060094 SN - 2075-4663 VL - 10 SP - 1 EP - 20 PB - MDPI CY - Basel, Schweiz ET - 6 ER - TY - GEN A1 - Sariati, Dorsaf A1 - Zouhal, Hassane A1 - Hammami, Raouf A1 - Clark, Cain Craig Truman A1 - Nebigh, Ammar A1 - Chtara, Moktar A1 - Hackney, Anthony C. A1 - Souissi, Nizar A1 - Granacher, Urs A1 - Ben Ounis, Omar T1 - Association Between Mental Imagery and Change of Direction Performance in Young Elite Soccer Players of Different Maturity Status T2 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Previous studies have not considered the potential influence of maturity status on the relationship between mental imagery and change of direction (CoD) speed in youth soccer. Accordingly, this cross-sectional study examined the association between mental imagery and CoD performance in young elite soccer players of different maturity status. Forty young male soccer players, aged 10-17 years, were assigned into two groups according to their predicted age at peak height velocity (PHV) (Pre-PHV; n = 20 and Post-PHV; n = 20). Participants were evaluated on soccer-specific tests of CoD with (CoDBall-15m) and without (CoD-15m) the ball. Participants completed the movement imagery questionnaire (MIQ) with the three- dimensional structure, internal visual imagery (IVI), external visual imagery (EVI), as well as kinesthetic imagery (KI). The Post-PHV players achieved significantly better results than Pre-PHV in EVI (ES = 1.58, large; p < 0.001), CoD-15m (ES = 2.09, very large; p < 0.001) and CoDBall-15m (ES = 1.60, large; p < 0.001). Correlations were significantly different between maturity groups, where, for the pre-PHV group, a negative very large correlation was observed between CoDBall-15m and KI (r = –0.73, p = 0.001). For the post-PHV group, large negative correlations were observed between CoD-15m and IVI (r = –0.55, p = 0.011), EVI (r = –062, p = 0.003), and KI (r = –0.52, p = 0.020). A large negative correlation of CoDBall-15m with EVI (r = –0.55, p = 0.012) and very large correlation with KI (r = –0.79, p = 0.001) were also observed. This study provides evidence of the theoretical and practical use for the CoD tasks stimulus with imagery. We recommend that sport psychology specialists, coaches, and athletes integrated imagery for CoD tasks in pre-pubertal soccer players to further improve CoD related performance. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 754 KW - mental imagery KW - football KW - maturation KW - speed KW - adolescents Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-544655 SN - 1866-8364 SP - 1 EP - 9 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Sariati, Dorsaf A1 - Zouhal, Hassane A1 - Hammami, Raouf A1 - Clark, Cain Craig Truman A1 - Nebigh, Ammar A1 - Chtara, Moktar A1 - Hackney, Anthony C. A1 - Souissi, Nizar A1 - Granacher, Urs A1 - Ben Ounis, Omar T1 - Association Between Mental Imagery and Change of Direction Performance in Young Elite Soccer Players of Different Maturity Status JF - Frontiers in Psychology N2 - Previous studies have not considered the potential influence of maturity status on the relationship between mental imagery and change of direction (CoD) speed in youth soccer. Accordingly, this cross-sectional study examined the association between mental imagery and CoD performance in young elite soccer players of different maturity status. Forty young male soccer players, aged 10-17 years, were assigned into two groups according to their predicted age at peak height velocity (PHV) (Pre-PHV; n = 20 and Post-PHV; n = 20). Participants were evaluated on soccer-specific tests of CoD with (CoDBall-15m) and without (CoD-15m) the ball. Participants completed the movement imagery questionnaire (MIQ) with the three- dimensional structure, internal visual imagery (IVI), external visual imagery (EVI), as well as kinesthetic imagery (KI). The Post-PHV players achieved significantly better results than Pre-PHV in EVI (ES = 1.58, large; p < 0.001), CoD-15m (ES = 2.09, very large; p < 0.001) and CoDBall-15m (ES = 1.60, large; p < 0.001). Correlations were significantly different between maturity groups, where, for the pre-PHV group, a negative very large correlation was observed between CoDBall-15m and KI (r = –0.73, p = 0.001). For the post-PHV group, large negative correlations were observed between CoD-15m and IVI (r = –0.55, p = 0.011), EVI (r = –062, p = 0.003), and KI (r = –0.52, p = 0.020). A large negative correlation of CoDBall-15m with EVI (r = –0.55, p = 0.012) and very large correlation with KI (r = –0.79, p = 0.001) were also observed. This study provides evidence of the theoretical and practical use for the CoD tasks stimulus with imagery. We recommend that sport psychology specialists, coaches, and athletes integrated imagery for CoD tasks in pre-pubertal soccer players to further improve CoD related performance. KW - mental imagery KW - football KW - maturation KW - speed KW - adolescents Y1 - 2021 U6 - https://doi.org/10.3389/fpsyg.2021.665508 SN - 1664-1078 VL - 12 SP - 1 EP - 9 PB - Frontiers Research Foundation CY - Lausanne, Schweiz ER - TY - JOUR A1 - Sariati, Dorsaf A1 - Hammami, Raouf A1 - Zouhal, Hassane A1 - Clark, Cain Craig Truman A1 - Nebigh, Ammar A1 - Chtara, Moktar A1 - Chortane, Sabri Gaied A1 - Hackney, Anthony C. A1 - Souissi, Nizar A1 - Granacher, Urs A1 - Ben Ounis, Omar ED - Trecroci, Athos T1 - Improvement of Physical Performance Following a 6 Week Change-of-Direction Training Program in Elite Youth Soccer Players of Different Maturity Levels JF - Frontiers in physiology N2 - Background: Change-of-direction (CoD) is a necessary physical ability of a field sport and may vary in youth players according to their maturation status. Objectives: The aim of this study is: to compare the effectiveness of a 6-week CoD training intervention on dynamic balance (CS-YBT), horizontal jump (5JT), speed (10 and 30-m linear sprint times), CoD with (15 m-CoD + B) and without (15 m-CoD) the ball, in youth male soccer players at different levels of maturity [pre- and post-peak height velocity (PHV)]. Materials and Methods: Thirty elite male youth soccer players aged 10–17 years from the Tunisian first division participated in this study. The players were divided into pre- (G1, n = 15) and post-PHV (G2, n = 15) groups. Both groups completed a similar 6-week training program with two sessions per week of four CoD exercises. All players completed the following tests before and after intervention: CS-YBT; 5 JT; 10, 30, and 15 m-CoD; and 15 m-CoD + B, and data were analyzed using ANCOVA. Results: All 30 players completed the study according to the study design and methodology. Adherence rate was 100% across all groups, and no training or test-related injuries were reported. Pre-PHV and post-PHV groups showed significant amelioration post-intervention for all dependent variables (after test > before test; p < 0.01, d = 0.09–1.51). ANOVA revealed a significant group × time interaction only for CS-YBT (F = 4.45; p < 0.04; η2 = 0.14), 5JT (F = 6.39; p < 0.02; η2 = 0.18), and 15 m-CoD (F = 7.88; p < 0.01; η2 = 0.22). CS-YBT, 5JT, and 15 m-CoD improved significantly in the post-PHV group (+ 4.56%, effect size = 1.51; + 4.51%, effect size = 1.05; and -3.08%, effect size = 0.51, respectively), more than the pre-PHV group (+ 2.77%, effect size = 0.85; + 2.91%, effect size = 0.54; and -1.56%, effect size = 0.20, respectively). Conclusion: The CoD training program improved balance, horizontal jump, and CoD without the ball in male preadolescent and adolescent soccer players, and this improvement was greater in the post-PHV players. The maturity status of the athletes should be considered when programming CoD training for soccer players. KW - youth soccer KW - peak height velocity KW - change of direction speed KW - training adaptation KW - football Y1 - 2021 U6 - https://doi.org/10.3389/fphys.2021.668437 SN - 1664-042X VL - 12 SP - 1 EP - 8 PB - Frontiers Research Foundation CY - Lausanne, Schweiz ER - TY - GEN A1 - Granacher, Urs A1 - Nobari, Hadi A1 - Ruivo Alves, Ana A1 - Clemente, Filipe Manuel A1 - Pérez-Gómez, Jorge A1 - Clark, Cain Craig Truman A1 - Zouhal, Hassane T1 - Associations Between Variations in Accumulated Workload and Physiological Variables in Young Male Soccer Players Over the Course of a Season T2 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe N2 - This study sought to analyze the relationship between in-season training workload with changes in aerobic power (VO2max), maximum and resting heart rate (HRmax and HRrest), linear sprint medium (LSM), and short test (LSS), in soccer players younger than 16 years (under-16 soccer players). We additionally aimed to explain changes in fitness levels during the in-season through regression models, considering accumulated load, baseline levels, and peak height velocity (PHV) as predictors. Twenty-three male sub-elite soccer players aged 15.5 ± 0.2 years (PHV: 13.6 ± 0.4 years; body height: 172.7 ± 4.2 cm; body mass: 61.3 ± 5.6 kg; body fat: 13.7% ± 3.9%; VO2max: 48.4 ± 2.6 mL⋅kg–1⋅min–1), were tested three times across the season (i.e., early-season (EaS), mid-season (MiS), and end-season (EnS) for VO2max, HRmax, LSM, and LSS. Aerobic and speed variables gradually improved over the season and had a strong association with PHV. Moreover, the HRmax demonstrated improvements from EaS to EnS; however, this was more evident in the intermediate period (from EaS to MiS) and had a strong association with VO2max. Regression analysis showed significant predictions for VO2max [F(2, 20) = 8.18, p ≤ 0.001] with an R2 of 0.45. In conclusion, the meaningful variation of youth players’ fitness levels can be observed across the season, and such changes can be partially explained by the load imposed. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 741 KW - internal load KW - heart rate KW - linear sprint KW - aerobic power KW - football Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-540440 SN - 1866-8364 SP - 1 EP - 12 PB - Universität Potsdam CY - Potsdam ER - TY - JOUR A1 - Negra, Yassine A1 - Chaabene, Helmi A1 - Sammoud, Senda A1 - Prieske, Olaf A1 - Moran, Jason A1 - Ramirez-Campillo, Rodrigo A1 - Nejmaoui, Ali A1 - Granacher, Urs T1 - The increased effectiveness of loaded versus unloaded plyometric jump training in improving muscle power, speed, change of direction, and kicking-distance performance in prepubertal male soccer players JF - International journal of sports physiology and performance : IJSSP N2 - Purpose: To examine the effects of loaded (LPJT) versus unloaded plyometric jump training (UPJT) programs on measures of muscle power, speed, change of direction (CoD), and kicking-distance performance in prepubertal male soccer players. Methods: Participants (N = 29) were randomly assigned to a LPJT group (n = 13; age = 13.0 [0.7] y) using weighted vests or UPJT group (n = 16; age = 13.0 [0.5] y) using body mass only. Before and after the intervention, tests for the assessment of proxies of muscle power (ie, countermovement jump, standing long jump); speed (ie, 5-, 10-, and 20-m sprint); CoD (ie, Illinois CoD test, modified 505 agility test); and kicking-distance were conducted. Data were analyzed using magnitude-based inferences. Results: Within-group analyses for the LPJT group showed large and very large improvements for 10-m sprint time (effect size [ES] = 2.00) and modified 505 CoD (ES = 2.83) tests, respectively. For the same group, moderate improvements were observed for the Illinois CoD test (ES = 0.61), 5- and 20-m sprint time test (ES = 1.00 for both the tests), countermovement jump test (ES = 1.00), and the maximal kicking-distance test (ES = 0.90). Small enhancements in the standing long jump test (ES = 0.50) were apparent. Regarding the UPJT group, small improvements were observed for all tests (ES = 0.33-0.57), except 5- and 10-m sprint time (ES = 1.00 and 0.63, respectively). Between-group analyses favored the LPJT group for the modified 505 CoD (ES = 0.61), standing long jump (ES = 0.50), and maximal kicking-distance tests (ES = 0.57), but not for the 5-m sprint time test (ES = 1.00). Only trivial between-group differences were shown for the remaining tests (ES = 0.00-0.09). Conclusion: Overall, LPJT appears to be more effective than UPJT in improving measures of muscle power, speed, CoD, and kicking-distance performance in prepubertal male soccer players. KW - young KW - football KW - stretch-shortening cycle KW - maturity KW - athletic KW - performance Y1 - 2020 U6 - https://doi.org/10.1123/ijspp.2018-0866 SN - 1555-0265 SN - 1555-0273 VL - 15 IS - 2 SP - 189 EP - 195 PB - Human Kinetics CY - Champaign, Ill. ER - TY - JOUR A1 - Moran, Jason A1 - Paxton, Kevin A1 - Jones, Ben A1 - Granacher, Urs A1 - Sandercock, Gavin Rh A1 - Hope, Edward A1 - Ramirez-Campillo, Rodrigo T1 - Variable long-term developmental trajectories of short sprint speed and jumping height in English Premier League academy soccer players: an applied case study JF - Journal of sports sciences N2 - Growth and maturation affect long term physical performance, making the appraisal of athletic ability difficult. We sought to longitudinally track youth soccer players to assess the developmental trajectory of athletic performance over a 6-year period in an English Premier League academy. Age-specific z-scores were calculated for sprint and jump performance from a sample of male youth soccer players (n = 140). A case study approach was used to analyse the longitudinal curves of the six players with the longest tenure. The trajectories of the sprint times of players 1 and 3 were characterised by a marked difference in respective performance levels up until peak height velocity (PHV) when player 1 achieved a substantial increase in sprint speed and player 3 experienced a large decrease. Player 5 was consistently a better performer than player 2 until PHV when the sprint and jump performance of the former markedly decreased and he was overtaken by the latter. Fluctuations in players' physical performance can occur quickly and in drastic fashion. Coaches must be aware that suppressed, or inflated, performance could be temporary and selection and deselection decisions should not be made based on information gathered over a short time period. KW - youth KW - football KW - talent KW - running velocity KW - muscular power Y1 - 2020 U6 - https://doi.org/10.1080/02640414.2020.1792689 SN - 0264-0414 SN - 1466-447X VL - 38 IS - 22 SP - 2525 EP - 2531 PB - Routledge, Taylor & Francis Group CY - London ER -