@article{RamirezCampilloAlvarezGarciaPinillosetal.2018, author = {Ramirez-Campillo, Rodrigo and Alvarez, Cristian and Garcia-Pinillos, Felipe and Sanchez-Sanchez, Javier and Yanci, Javier and Castillo, Daniel and Loturco, Irineu and Chaabene, Helmi and Moran, Jason and Izquierdo, Mikel}, title = {Optimal reactive strength index}, series = {Journal of strength and conditioning research : the research journal of the NSCA}, volume = {32}, journal = {Journal of strength and conditioning research : the research journal of the NSCA}, number = {4}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, issn = {1064-8011}, doi = {10.1519/JSC.0000000000002467}, pages = {885 -- 893}, year = {2018}, abstract = {Ramirez-Campillo, R, Alvarez, C, Garc{\´i}a-Pinillos, F, Sanchez-Sanchez, J, Yanci, J, Castillo, D, Loturco, I, Chaabene, H, Moran, J, and Izquierdo, M. Optimal reactive strength index: is it an accurate variable to optimize plyometric training effects on measures of physical fitness in young soccer players? J Strength Cond Res 32(4): 885-893, 2018—This study aimed to compare the effects of drop-jump training using a fixed drop-box height (i.e., 30-cm [FIXED]) vs. an optimal (OPT) drop-box height (i.e., 10-cm to 40-cm: generating an OPT reactive strength index [RSI]) in youth soccer players' physical fitness. Athletes were randomly allocated to a control group (n = 24; age = 13.7 years), a fixed drop-box height group (FIXED, n = 25; age = 13.9 years), or an OPT drop-box height group (OPT, n = 24; age = 13.1 years). Before and after 7 weeks of training, tests for the assessment of jumping (countermovement jump [CMJ], 5 multiple bounds), speed (20-m sprint time), change of direction ability (CODA [Illinois test]), strength {RSI and 5 maximal squat repetition test (5 repetition maximum [RM])}, endurance (2.4-km time trial), and kicking ability (maximal kicking distance) were undertaken. Analyses revealed main effects of time for all dependent variables (p < 0.001, d = 0.24-0.72), except for 20-m sprint time. Analyses also revealed group × time interactions for CMJ (p < 0.001, d = 0.51), depth jump (DJ) (p < 0.001, d = 0.30), 20-m sprint time (p < 0.001, d = 0.25), CODA (p < 0.001, d = 0.22), and 5RM (p < 0.01, d = 0.16). Post hoc analyses revealed increases for the FIXED group (CMJ: 7.4\%, d = 0.36; DJ: 19.2\%, d = 0.49; CODA: -3.1\%, d = -0.21; 5RM: 10.5\%, d = 0.32) and the OPT group (CMJ: 16.7\%, d = 0.76; DJ: 36.1\%, d = 0.79; CODA: -4.4\%, d = -0.34; 5RM: 18.1\%, d = 0.47). Post hoc analyses also revealed increases for the OPT group in 20-m sprint time (-3.7\%, d = 0.27). Therefore, to maximize the effects of plyometric training, an OPT approach is recommended. However, using adequate fixed drop-box heights may provide a rational and practical alternative.}, language = {en} } @misc{RamirezCampilloAlvarezGarciaHermosoetal.2018, author = {Ramirez-Campillo, Rodrigo and Alvarez, Cristian and Garcia-Hermoso, Antonio and Ramirez-Velez, Robinson and Gentil, Paulo and Asadi, Abbas and Chaabene, Helmi and Moran, Jason and Meylan, Cesar and Garcia-de-Alcaraz, Antonio and Sanchez-Sanchez, Javier and Nakamura, Fabio Y. and Granacher, Urs and Kraemer, William and Izquierdo, Mikel}, title = {Methodological characteristics and future directions for plyometric jump training research}, series = {Sports medicine}, volume = {48}, journal = {Sports medicine}, number = {5}, publisher = {Springer}, address = {Northcote}, issn = {0112-1642}, doi = {10.1007/s40279-018-0870-z}, pages = {1059 -- 1081}, year = {2018}, abstract = {Recently, there has been a proliferation of published articles on the effect of plyometric jump training, including several review articles and meta-analyses. However, these types of research articles are generally of narrow scope. Furthermore, methodological limitations among studies (e.g., a lack of active/passive control groups) prevent the generalization of results, and these factors need to be addressed by researchers. On that basis, the aims of this scoping review were to (1) characterize the main elements of plyometric jump training studies (e.g., training protocols) and (2) provide future directions for research. From 648 potentially relevant articles, 242 were eligible for inclusion in this review. The main issues identified related to an insufficient number of studies conducted in females, youths, and individual sports (~ 24.0, ~ 37.0, and ~ 12.0\% of overall studies, respectively); insufficient reporting of effect size values and training prescription (~ 34.0 and ~ 55.0\% of overall studies, respectively); and studies missing an active/passive control group and randomization (~ 40.0 and ~ 20.0\% of overall studies, respectively). Furthermore, plyometric jump training was often combined with other training methods and added to participants' daily training routines (~ 47.0 and ~ 39.0\% of overall studies, respectively), thus distorting conclusions on its independent effects. Additionally, most studies lasted no longer than 7 weeks. In future, researchers are advised to conduct plyometric training studies of high methodological quality (e.g., randomized controlled trials). More research is needed in females, youth, and individual sports. Finally, the identification of specific dose-response relationships following plyometric training is needed to specifically tailor intervention programs, particularly in the long term.}, language = {en} } @misc{MoranRamirezCampilloGranacher2018, author = {Moran, Jason and Ramirez-Campillo, Rodrigo and Granacher, Urs}, title = {Effects of Jumping Exercise on Muscular Power in Older Adults}, series = {Sports medicine}, volume = {48}, journal = {Sports medicine}, number = {12}, publisher = {Springer}, address = {Northcote}, issn = {0112-1642}, doi = {10.1007/s40279-018-1002-5}, pages = {2843 -- 2857}, year = {2018}, abstract = {Background Jump training (JT) can be used to enhance the ability of skeletal muscle to exert maximal force in as short a time as possible. Despite its usefulness as a method of performance enhancement in athletes, only a small number of studies have investigated its effects on muscle power in older adults. Objectives The aims of this meta-analysis were to measure the effect of JT on muscular power in older adults (≥ 50 years), and to establish appropriate programming guidelines for this population. Data Sources The data sources utilised were Google Scholar, PubMed, and Microsoft Academic. Study Eligibility Criteria Studies were eligible for inclusion if they comprised JT interventions in healthy adults (≥ 50 years) who were free of any medical condition that could impair movement. Study Appraisal and Synthesis Methods The inverse variance random-effects model for meta-analyses was used because it allocates a proportionate weight to trials based on the size of their individual standard errors and facilitates analysis while accounting for heterogeneity across studies. Effect sizes (ESs), calculated from a measure of muscular power, were represented by the standardised mean difference and were presented alongside 95\% confidence intervals (CIs). Results Thirteen training groups across nine studies were included in this meta-analysis. The magnitude of the main effect was 'moderate' (0.66, 95\% CI 0.33, 0.98). ESs were larger in non-obese participants (body mass index [BMI] < 30 vs. ≥ 30 kg/m2; 1.03 [95\% CI 0.34, 1.73] vs. 0.53 [95\% CI - 0.03, 1.09]). Among the studies included in this review, just one reported an acute injury, which did not result in the participant ceasing their involvement. JT was more effective in programmes with more than one exercise (range 1-4 exercises; ES = 0.74 [95\% CI - 0.49, 1.96] vs. 0.53 [95\% CI 0.29, 0.78]), more than two sets per exercise (range 1-4 sets; ES = 0.91 [95\% CI 0.04, 1.77] vs. 0.68 [95\% CI 0.15, 1.21]), more than three jumps per set (range 1-14 jumps; ES = 1.02 [95\% CI 0.16, 1.87] vs. 0.53 [95\% CI - 0.03, 1.09]) and more than 25 jumps per session (range 6-200 jumps; ES = 0.88 [95\% CI 0.05, 1.70] vs. 0.49 [95\% CI 0.14, 0.83]). Conclusions JT is safe and effective in older adults. Practitioners should construct varied JT programmes that include more than one exercise and comprise more than two sets per exercise, more than three jumps per set, and 60 s of recovery between sets. An upper limit of three sets per exercise and ten jumps per set is recommended. Up to three training sessions per week can be performed.}, language = {en} } @misc{MoranBlagroveDruryetal.2019, author = {Moran, Jason and Blagrove, Richard C. and Drury, Benjamin and Fernandes, John F. T. and Paxton, Kevin and Chaabene, Helmi and Ramirez-Campillo, Rodrigo}, title = {Effects of Small-Sided Games vs. Conventional Endurance Training on Endurance Performance in Male Youth Soccer Players: A Meta-Analytical Comparison}, series = {Sports medicine}, volume = {49}, journal = {Sports medicine}, number = {5}, publisher = {Springer}, address = {Northcote}, issn = {0112-1642}, doi = {10.1007/s40279-019-01086-w}, pages = {731 -- 742}, year = {2019}, abstract = {Background Small-sided games have been suggested as a viable alternative to conventional endurance training to enhance endurance performance in youth soccer players. This has important implications for long-term athlete development because it suggests that players can increase aerobic endurance through activities that closely resemble their sport of choice. Data Sources The data sources utilised were Google Scholar, PubMed and Microsoft Academic. Study Eligibility Criteria Studies were eligible for inclusion if interventions were carried out in male soccer players (aged < 18years) and compared the effects of small-sided games and conventional endurance training on aerobic endurance performance. We defined small-sided games as modified [soccer] games played on reduced pitch areas, often using adapted rules and involving a smaller number of players than traditional games. We defined conventional endurance training as continuous running or extensive interval training consisting of work durations>3min. Study Appraisal and Synthesis Methods The inverse-variance random-effects model for meta-analyses was used because it allocates a proportionate weight to trials based on the size of their individual standard errors and facilitates analysis whilst accounting for heterogeneity across studies. Effect sizes were represented by the standardised mean difference and presented alongside 95\% confidence intervals. Results Seven studies were included in this meta-analysis. Both modes of training were effective in increasing endurance performance. Within-mode effect sizes were both of moderate magnitude [small-sided games: 0.82 (95\% confidence interval 0.05, 1.60), Z=2.07 (p=0.04); conventional endurance training: 0.89 (95\% confidence interval 0.06, 1.72), Z=2.10 (p=0.04)]. There were only trivial differences [0.04 (95\% confidence interval -0.36, 0.43), Z=0.18 (p=0.86)] between the effects on aerobic endurance performance of small-sided games and conventional endurance training. Subgroup analyses showed mostly trivial differences between the training methods across key programming variables such as set duration (>= or < 4 min) and recovery period between sets (>= or< 3min). Programmes that were longer than 8 weeks favoured small-sided games [effect size=0.45 (95\% confidence interval -0.12, 1.02), Z=1.54 (p=0.12)], with the opposite being true for conventional endurance training [effect size=-0.33 (95\% confidence interval -0.79, 0.14), Z=1.39 (p=0.16)]. Programmes with more than 4 sets per session favoured small-sided games [effect size=0.53 (95\% confidence interval -0.52, 1.58), Z=0.98 (p=0.33)] with only a trivial difference between those with 4, or fewer, sets [effect size=-0.13 (95\% confidence interval -0.52, 0.26), Z=0.65 (p=0.52)]. Conclusions Small-sided games are as effective as conventional endurance training for increasing aerobic endurance performance in male youth soccer players. This is important for practitioners as it means that small-sided games can allow both endurance and skills training to be carried out simultaneously, thus providing a more efficient training stimulus. Small-sided games offer the same benefits as conventional endurance training with two sessions per week, with4 sets of 4 min of activity, interspersed with recovery periods of 3min, recommended in this population.}, language = {en} } @article{SammoudNegraChaabeneetal.2019, author = {Sammoud, Senda and Negra, Yassine and Chaabene, Helmi and Bouguezzi, Raja and Moran, Jason and Granacher, Urs}, title = {The Effects of Plyometric Jump Training on Jumping and Swimming Performances in Prepubertal Male Swimmers}, series = {Journal of sports science \& medicine}, volume = {18}, journal = {Journal of sports science \& medicine}, number = {4}, publisher = {Department of Sports Medicine, Medical Faculty of Uludag University}, address = {Bursa}, issn = {1303-2968}, pages = {805 -- 811}, year = {2019}, abstract = {Swimming performance can be improved not only by in-water sport-specific training but also by means of dry land-training (e.g., plyometric jump training [PJT]). This study examined the effects of an 8-week PJT on proxies of muscle power and swimming performance in prepubertal male swimmers. Participants were randomly allocated to a PJT group (PJT; n = 14; age: 10.3 +/- 0.4 years, maturity-offset = -3 +/- 0.3) or a control group (CG; n = 12; age: 10.5 +/- 0.4 years, maturity-offset = -2.8 +/- 0.3). Swimmers in PJT and CG performed 6 training sessions per week. Each training session lasted between 80 and 90 minutes. Over the 8 weeks in-season training period, PJT performed two PJT sessions per week, each lasting between 25 to 30 minutes (similar to 1 hour per week) in replacement of sport-specific swimming drills. During that time, CG followed their regular sport-specific swimming training (e.g., coordination, breathing, improving swimming strokes). Overall training volume was similar between groups. Pre- and post-training, tests were conducted to assess proxies of muscle power (countermovement-jump [CMJ]), standing-long-jump [SLJ]) and sport-specific swimming performances (15-, 25-, and 50-m front-crawl, 25-m kick without push [25-m kick WP], and 25-m front-crawl WP). No training or test-related injuries were detected over the course of the study. Between-group analyses derived from magnitude-based inferences showed trivial-to-large effects in favour of PJT for all tests (ES = 0.28 to 1.43). Within-group analyses for the PJT showed small performance improvements for CMJ (effect-size [ES] = 0.53), 25-m kick WP (ES = 0.25), and 50-m front crawl (ES = 0.56) tests. Moderate performance improvements were observed for the SLJ, 25-m front-crawl WP, 15-m and 25-m front-crawl tests (ES = 0.95, 0.60, 0.99, and 0.85, respectively). For CG, the within-group results showed trivial performance declines for the CMJ (ES=-0.13) and the 50-m front-crawl test (ES = -0.04). In addition, trivial-to-small performance improvements were observed for the SLJ (ES = 0.09), 25-m kick WP (ES = 0.02), 25-m front-crawl WP (ES = 0.19), 25-m front-crawl (ES = 0.2), (SLJ [ES = 0.09, and 15-m front crawl (ES = 0.36). Short-term in-season PJT, integrated into the regular swimming training, was more effective than regular swimming training alone in improving jump and sport-specific swimming performances in prepubertal male swimmers.}, language = {en} } @article{RamirezCampilloAndradeNikolaidisetal.2020, author = {Ramirez-Campillo, Rodrigo and Andrade, David C. and Nikolaidis, Pantelis T. and Moran, Jason and Clemente, Filipe Manuel and Chaabene, Helmi and Comfort, Paul}, title = {Effects of plyometric jump training on vertical jump height of volleyball players: a systematic review with meta-analysis of randomized-controlled trial}, series = {Journal of Sports Science and Medicine}, volume = {19}, journal = {Journal of Sports Science and Medicine}, publisher = {Wiley-Blackwell}, address = {Oxford}, pages = {11}, year = {2020}, abstract = {This meta-analysis aimed to assess the effects of plyometric jump training (PJT) on volleyball players' vertical jump height (VJH), comparing changes with those observed in a matched control group. A literature search in the databases of PubMed, MEDLINE, Web of Science, and SCOPUS was conducted. Only randomized-controlled trials and studies that included a pre-to-post intervention assessment of VJH were included. They involved only healthy volleyball players with no restrictions on age or sex. Data were independently extracted from the included studies by two authors. The Physiotherapy Evidence Database scale was used to assess the risk of bias, and methodological quality, of eligible studies included in the review. From 7,081 records, 14 studies were meta-analysed. A moderate Cohen's d effect size (ES = 0.82, p <0.001) was observed for VJH, with moderate heterogeneity (I2 = 34.4\%, p = 0.09) and no publication bias (Egger's test, p = 0.59). Analyses of moderator variables revealed no significant differences for PJT program duration (≤8 vs. >8 weeks, ES = 0.79 vs. 0.87, respectively), frequency (≤2 vs. >2 sessions/week, ES = 0.83 vs. 0.78, respectively), total number of sessions (≤16 vs. >16 sessions, ES = 0.73 vs. 0.92, respectively), sex (female vs. male, ES = 1.3 vs. 0.5, respectively), age (≥19 vs. <19 years of age, ES = 0.89 vs. 0.70, respectively), and volume (>2,000 vs. <2,000 jumps, ES = 0.76 vs. 0.79, respectively). In conclusion, PJT appears to be effective in inducing improvements in volleyball players' VJH. Improvements in VJH may be achieved by both male and female volleyball players, in different age groups, with programs of relatively low volume and frequency. Though PJT seems to be safe for volleyball players, it is recommended that an individualized approach, according to player position, is adopted with some players (e.g. libero) less prepared to sustain PJT loads.}, language = {en} } @article{NegraChaabeneSammoudetal.2020, author = {Negra, Yassine and Chaabene, Helmi and Sammoud, Senda and Prieske, Olaf and Moran, Jason and Ramirez-Campillo, Rodrigo and Nejmaoui, Ali and Granacher, Urs}, title = {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}, series = {International journal of sports physiology and performance : IJSSP}, volume = {15}, journal = {International journal of sports physiology and performance : IJSSP}, number = {2}, publisher = {Human Kinetics}, address = {Champaign, Ill.}, issn = {1555-0265}, doi = {10.1123/ijspp.2018-0866}, pages = {189 -- 195}, year = {2020}, abstract = {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.}, language = {en} } @article{ChaabenePrieskeMoranetal.2020, author = {Chaabene, Helmi and Prieske, Olaf and Moran, Jason and Negra, Yassine and Attia, Ahmed and Granacher, Urs}, title = {Effects of resistance training on Change-of-Direction speed in youth and young physically active and athletic adults: a systematic review with meta-analysis}, series = {Sports medicine : the world's premier sports medicine preview journal}, volume = {50}, journal = {Sports medicine : the world's premier sports medicine preview journal}, number = {8}, publisher = {Springer}, address = {Berlin [u.a.]}, issn = {0112-1642}, doi = {10.1007/s40279-020-01293-w}, pages = {1483 -- 1499}, year = {2020}, abstract = {Background Change-of-direction (CoD) speed is a physical fitness attribute in many field-based team and individual sports. To date, no systematic review with meta-analysis available has examined the effects of resistance training (RT) on CoD speed in youth and adults. Objective To aggregate the effects of RT on CoD speed in youth and young physically active and athletic adults, and to identify the key RT programme variables for training prescription. Data sources A systematic literature search was conducted with PubMed, Web of Science, and Google Scholar, with no date restrictions, up to October 2019, to identify studies related to the effects of RT on CoD speed. Study Eligibility Criteria Only controlled studies with baseline and follow-up measures were included if they examined the effects of RT (i.e., muscle actions against external resistances) on CoD speed in healthy youth (8-18 years) and young physically active/athletic male or female adults (19-28 years). Study Appraisal and Synthesis Methods A random-effects model was used to calculate weighted standardised mean differences (SMD) between intervention and control groups. In addition, an independent single training factor analysis (i.e., RT frequency, intensity, volume) was undertaken. Further, to verify if any RT variable moderated effects on CoD speed, a multivariate random-effects meta-regression was conducted. The methodological quality of the included studies was assessed using the physiotherapy evidence database (PEDro) scale. Results Fifteen studies, comprising 19 experimental groups, were included. The methodological quality of the studies was acceptable with a median PEDro score of 6. There was a significant large effect size of RT on CoD speed across all studies (SMD = - 0.82 [- 1.14 to - 0.49]). Subgroup analyses showed large effect sizes on CoD speed in males (SMD = - 0.95) contrasting with moderate improvements in females (SMD = - 0.60). There were large effect sizes on CoD speed in children (SMD = - 1.28) and adolescents (SMD = - 1.21) contrasting with moderate effects in adults (SMD = - 0.63). There was a moderate effect in elite athletes (SMD = - 0.69) contrasting with a large effect in subelite athletes (SMD = - 0.86). Differences between subgroups were not statistically significant. Similar improvements were observed regarding the effects of independently computed training variables. In terms of RT frequency, our results indicated that two sessions per week induced large effects on CoD speed (SMD = - 1.07) while programmes with three sessions resulted in moderate effects (SMD = - 0.53). For total training intervention duration, we observed large effects for <= 8 weeks (SMD = - 0.81) and > 8 weeks (SMD = - 0.85). For single session duration, we found large effects for <= 30 min and >= 45 min (both SMD = - 1.00). In terms of number of training sessions, we identified large effects for <= 16 sessions (SMD = - 0.83) and > 16 sessions (SMD = - 0.81). For training intensity, we found moderate effects for light-to-moderate (SMD = - 0.76) and vigorous-to-near maximal intensities (SMD = - 0.77). With regards to RT type, we observed large effects for free weights (SMD = - 0.99) and machine-based training (SMD = - 0.80). For combined free weights and machine-based training, moderate effects were identified (SMD = - 0.77). The meta-regression outcomes showed that none of the included training variables significantly predicted the effects of RT on CoD speed (R-2 = 0.00). Conclusions RT seems to be an effective means to improve CoD speed in youth and young physically active and athletic adults. Our findings indicate that the impact of RT on CoD speed may be more prominent in males than in females and in youth than in adults. Additionally, independently computed single factor analyses for different training variables showed that higher compared with lower RT intensities, frequencies, and volumes appear not to have an advantage on the magnitude of CoD speed improvements. In terms of RT type, similar improvements were observed following machine-based and free weights training.}, language = {en} } @article{MoranPaxtonJonesetal.2020, author = {Moran, Jason and Paxton, Kevin and Jones, Ben and Granacher, Urs and Sandercock, Gavin Rh and Hope, Edward and Ramirez-Campillo, Rodrigo}, title = {Variable long-term developmental trajectories of short sprint speed and jumping height in English Premier League academy soccer players: an applied case study}, series = {Journal of sports sciences}, volume = {38}, journal = {Journal of sports sciences}, number = {22}, publisher = {Routledge, Taylor \& Francis Group}, address = {London}, issn = {0264-0414}, doi = {10.1080/02640414.2020.1792689}, pages = {2525 -- 2531}, year = {2020}, abstract = {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.}, language = {en} } @article{CoppalleRaveMoranetal.2021, author = {Coppalle, Sullivan and Rav{\´e}, Guillaume and Moran, Jason and Salhi, Iyed and Ben Abderrahman, Abderraouf and Zouita, Sghaeir and Granacher, Urs and Zouhal, Hassane}, title = {Internal and External Training Load in Under-19 versus Professional Soccer Players during the In-Season Period}, series = {International Journal of Environmental Research and Public Health}, volume = {18}, journal = {International Journal of Environmental Research and Public Health}, number = {2}, publisher = {MDPI AG}, address = {Basel}, issn = {1660-4601}, doi = {10.3390/ijerph18020558}, pages = {10}, year = {2021}, abstract = {This study aimed to compare the training load of a professional under-19 soccer team (U-19) to that of an elite adult team (EAT), from the same club, during the in-season period. Thirty-nine healthy soccer players were involved (EAT [n = 20]; U-19 [n = 19]) in the study which spanned four weeks. Training load (TL) was monitored as external TL, using a global positioning system (GPS), and internal TL, using a rating of perceived exertion (RPE). TL data were recorded after each training session. During soccer matches, players' RPEs were recorded. The internal TL was quantified daily by means of the session rating of perceived exertion (session-RPE) using Borg's 0-10 scale. For GPS data, the selected running speed intensities (over 0.5 s time intervals) were 12-15.9 km/h; 16-19.9 km/h; 20-24.9 km/h; >25 km/h (sprint). Distances covered between 16 and 19.9 km/h, > 20 km/h and >25 km/h were significantly higher in U-19 compared to EAT over the course of the study (p = 0.023, d = 0.243, small; p = 0.016, d = 0.298, small; and p = 0.001, d = 0.564, small, respectively). EAT players performed significantly fewer sprints per week compared to U-19 players (p = 0.002, d = 0.526, small). RPE was significantly higher in U-19 compared to EAT (p = 0.001, d = 0.188, trivial). The external and internal measures of TL were significantly higher in the U-19 group compared to the EAT soccer players. In conclusion, the results obtained show that the training load is greater in U19 compared to EAT.}, language = {en} }