Internal load in elite young soccer players during a whole season according to playing positions

The aims of this study were 1) to compare the internal load, measured as session rating of perceived exertion (s-RPE), between training sessions and official matches among playing positions in young elite soccer players and 2) to analyze the s-RPE association between training and official match-play. Nineteen young elite soccer players who competed in the Spanish First Division Under-19 Championship participated in this study. Internal load was registered during 120 training sessions and during 30 official matches. Only the players who participated in all the weekly sessions and played at least 70 min were included in the further analysis. No significant differences (P > 0.05, ES = -0.57/0.62) among playing positions were found in the s-RPE registered by soccer players in training sessions, official matches nor in the total sessions. On the other side, higher s-RPE was observed during trainings in comparison to matches in each playing position (P < 0.001, ES = 5.51-30.77). However, no association was observed between training s-RPE and match s-RPE for the whole of the players (P = 0.60, r = 0.04), nor for each specific playing positions (P = 0.29-0.89, r = -0.11/0.16). These findings could be useful for coaches in order to plan the distribution of the weekly training load. Nonetheless, it is also suggested that internal load monitoring cannot be confidently used, in isolation, as a tool to detect differences in the matchplay demands, attending to playing positions, in young soccer players. Thus, the use of both internal (i.e., s-RPE) and external (i.e., global positioning system measures) load is suggested to manage the training and match load and to prescribe the training sessions appropriately

El entrenamiento de la fuerza para la mejora del rendimiento físico-deportivo y la prevención de lesiones en el fútbol

Programa de Doctorado en Ciencias de la Actividad Física y del DeporteLínea de Investigación: Factores Determinantes del Rendimiento Físico y DeportivoClave Programa: DAFCódigo Línea: 35Esta Tesis Doctoral versa sobre el fútbol, respecto a sus características y la aplicación de un entrenamiento de fuerza con sobrecarga excéntrica que incrementa en pocas semanas la potencia del tren inferior, y produce otras mejoras en variables relacionadas con el rendimiento en el fútbol. También se estudian los efectos de 2 programas de entrenamiento neuromuscular con diferente orientación, para conocer la mejora de cada uno de ellos sobre los futbolistas y si estas mejoras son específicas a cada tipo de entrenamiento. Además, se realiza un estudio descriptivo sobre las lesiones que se producen a lo largo de una temporada en la cantera de un equipo de fútbol profesional, y se analiza el efecto de un programa de fuerza sobre la prevención de lesiones en fútbol. Los resultados obtenidos en los diferentes estudios demuestran que el fútbol es un deporte lesivo que varía según la categoría en el mismo club, que se producen más lesiones en partido que en entrenamiento, que un programa preventivo de fuerza es efectivo en la reducción del número de lesiones musculares en una temporada, que el entrenamiento con un dispositivo inercial con sobrecarga excéntrica mejora el salto vertical, el % de pérdida en el cambio de dirección y la potencia de piernas, y que las diferentes mejoras en el rendimiento en el fútbol depende del tipo de entrenamiento neuromuscular utilizado.Universidad Pablo de Olavide. Departamento de Deporte e InformáticaPostprin

Is a Maximal Strength-Training Program Effective on Physical Fitness, Injury Incidence, and Injury Burden in Semi-Professional Soccer Players? A Randomized Controlled Trial

The aims of the study were to analyze the effects of a 12-week maximal strength- training program on injury incidence, injury burden, and physical fitness in semi-professional soccer players and to compare the perceived exertion load and well-being state between injured and non-injured soccer players. Twenty semi-professional male soccer players participated in this study. Participants were randomly allocated to an experimental group (EG, n = 10 players), who performed a maximal strength-training program, or to a control group (CG, n = 10 players), who only performed their regular soccer training. Physical fitness was measured at baseline and after the training program. In addition, the injury incidence, burden, training/match load, and the state of well-being of the players were recorded. The EG showed significant improvements in vertical jumps, change in direction ability, linear sprints, repeated sprint ability, isometric strength (p < 0.003; effect size = 1.78–11.86), and quadriceps–hamstring imbalance in both legs (p < 0.001; effect size = 2.37–3.71) in comparison to the CG. In addition, the EG players showed a significantly (p < 0.05) lower injury burden (p < 0.001, relative risk = 5.05, 95% confidence interval = 3.27–7.79). This study demonstrated the beneficial effects of a 12-week maximal strength-training program on physical fitness attributes and injury burden in semi-professional soccer players.Javier Raya-González was supported by a Ramón y Cajal postdoctoral fellowship (RYC2021-031072-I) given by the Spanish Ministry of Science and Innovation, the State Research Agency (AEI), and the European Union (NextGenerationEU/PRTR)

Influence of Pitch Size on Short-Term High Intensity Actions and Body Impacts in Soccer Sided Games

The aim of this study was to compare external training loads between small-sided games (SSGs) and largesided games (LSGs) in soccer players. Twenty outfield soccer players (14.8 ± 0.6 years old) who competed in the Spanish U16 Provincial Division and belonged to the same team participated in the study. The soccer sided games were played at different individual interaction space (IIS) per player (i.e., SSG = 100 m2 and LSG = 200 m2) and were disputed in the same format (five-a-side plus goalkeepers) on two different pitch sizes (i.e., 38 x 26 vs. 53 x 37 m) defending an official soccer-goal. The sided games' duration was 4 bouts of 6 min with 2 min rest intervals between bouts. The results of this study showed no meaningful differences in the total distance and intensity of accelerations and decelerations between SSGs and LSGs except for the lower distance covered at medium intensity (2.5 - 4 m·s-2) observed during LSGs (-10.2%; ES (effect size): -0.51). Players registered greater sprints, maximum velocity (Velmax) and body impacts at different intensities (i.e., I5-6g, I6-6.5g, I6.5-7g, I7-8g, I8-10g,) in LSGs in comparison to SSGs. These findings suggest that an increase in the pitch size (i.e., IIS per player) can induce higher external loads for soccer players.The authors gratefully acknowledge the support of a Spanish government subproject Mixed method approach on performance analysis (in training and competition) in elite and academy sport [PGC2018-098742-B-C33] (2019-2021), from Ministerio de Ciencia, Innovación y Universidades (MCIU), Agencia Estatal de Investigación (AEI), and Fondo Europeo de Desarrollo Regional (FEDER), that is part of the coordinated project New approach of research in physical activity and sport from mixed methods perspective (NARPAS_MM) [SPGC201800X098742CV0

Effects of including endurance and speed sessions withinsmall-sided soccer games periodization on physical fitness

The main aim of this study was to analyse the effects of including additional speed and endurance sessions during small-sided games (SSG) training periodization on physical fitness in professional soccer players. Sixteen outfield players (age = 25.6 +/- 7.6 years) who competed in the First Division of a European League participated in this study. Players were randomly assigned to perform only the SSG periodization (G-SSG group) or to add endurance and speed training contents to the SSG (ES-SSG group). Before and after the 6-week experimental period, a Yo-Yo Intermittent Recovery Test level 1 (YYIR1) and a 40 m sprinting test were performed. Rating of perceived exertion (RPE) was also measured after each training session. The G-SSG group showed a large improvement in the YYIR1 performance (p = 0.018-0.028; ES = 0.521-0.576) after the training programme, whereas no significant changes were observed for the ES-SSG group (p = 0.763-1.000; ES = 0.000-0.014). In addition, no significant differences (p > 0.05, ES = 0.005-361, trivial to small) in sprint performance at 5 and 10 m intervals up to 40 m were observed at post-training in comparison to pre-training evaluation in G-SSG and ES-SSG groups. No significant differences (p > 0.05) between groups were observed at baseline in the YYIR1 test. The 6-week SSG training supported with only six endurance and speed training sessions was no more effective than well-organized SSG alone for improving running endurance in professional soccer players.The project leading to these results has received funding from "La Caixa" Foundation (ID 100010434) and La Caja de Burgos, under agreement LCF/PR/PR18/51130008. The authors gratefully acknowledge the support of a Spanish government subproject Mixed method approach on performance analysis (in training and competition) in elite and academy sport [PGC2018-098742-B-C33] (2019-2021) [del Ministerio de Ciencia, Innovacion y Universidades (MCIU), la Agencia Estatal de Investigacion (AEI) y el Fondo Europeo de Desarrollo Regional (FEDER)], that is part of the coordinated project New approach of research in physical activity and sport from mixed methods perspective (NARPAS_MM) [SPGC201800X098742CV0]

Effects of Caffeine Supplementation on Power Performance in a Flywheel Device: A Randomised, Double-Blind Cross-Over Study

[EN] Despite the demonstrated evidence of the importance of eccentric contractions in sports performance, no research has evaluated the ergogenic effects of caffeine on this type of contraction means during flywheel exercises. Therefore, the aims of the present study were to compare the power outcomes, using different inertial loads, between caffeine and placebo conditions. Twenty-four young, healthy, and active men (age: 22.5 4.8 years) took part in the study. A crossed, randomised double-blind design was used to analyse the effects of caffeine on lower limb power outcomes during a flywheel half-squat exercise. Participants completed four sets of eight all-out repetitions with a fixed three-minutes rest interval, and each set was performed using different inertial loads (i.e., 0.025, 0.050, 0.075 and 0.100 kg m2). Both the mean power (MP) and peak power (PP) in concentric (CON) and eccentric (ECC) movement phases at each inertial load were recorded after participants were administered either a caffeine supplement (6 mg kg1) or placebo (sucrose). Participants receiving a caffeine supplementation demonstrated improvements versus the placebo in total MP (MPtotal), as well as MP in CON phase (MPcon) and in ECC phase (MPecc) at each inertial load (22.68 to 26.53%; p < 0.01, effect size (ES) = 0.89–1.40). In addition, greater improvements with caffeine ingestion were obtained with respect to the placebo condition (18.79 to 24.98%; p < 0.01, ES = 1.03–1.40) in total PP (PPtotal), as well as PP in CON phase (PPcon) and in ECC phase (PPecc) at each inertial load. Thus, the supplementation of 6 mg kg1 caffeine may be considered to maximise on-field physical performance in those sports characterised by high demands of resistance.SIThe costs of caffeine supplement, English translation, and publication costs will be paid by the University Isabel I, Burgos, Spain

A Comparison in Physical Fitness Attributes, Physical Activity Behaviors, Nutritional Habits, and Nutritional Knowledge Between Elite Male and Female Youth Basketball Players

Background: Limited evidence exists comprehensively assessing physical fitness attributes, physical activity behaviors, nutritional habits, and nutritional knowledge according to sex in basketball players during early adolescence. Insight of this nature could be used to optimize the training process and lifestyles in young basketball players. Objective: To compare physical fitness attributes, physical activity levels, nutritional habits, and nutritional knowledge between elite male and female basketball players under 14 years of age (U-14). Methods: Twenty-three U-14 basketball players (male, n = 13 and female, n = 10) from the same elite basketball academy (Spanish Asociacion de Clubes de Baloncesto [ACB] League) participated in this study. Physical fitness attributes were assessed using a basketball-specific test battery (countermovement jump, drop jump, linear sprint, Lane Agility Drill, 505 change-of-direction, and repeated-change-of-direction tests), while physical activity levels (Physical Activity Questionnaire for Adolescents, PAQ-A), nutritional habits (Turconi questionnaire), and nutritional knowledge (Turconi questionnaire) were assessed using questionnaires. Results: Male players exhibited better physical fitness in all tests (p 0.05). Of note, a high proportion of players declared never or only sometimes eating fruit (males: 23%; females: 40%) and vegetables (males: 46%; females: 70%). In addition, relatively poor nutritional knowledge was evident in all players with the group correctly answering <50% of nutritional questions overall (4.57 +/- 1.88 out of 11 points, 42%) and according to sex (males: 4.07 +/- 2.10, 37%; females: 5.20 +/- 1.40, 47%). Conclusion: These findings emphasize the necessity to perform individualized prescription of training stimuli across sexes to optimize the physical preparedness and development of youth basketball players. Additionally, strategies such as nutrition-focused education interventions may be necessary in this population given the low consumption of fruits and vegetables, as well as the poor nutritional knowledge observed in players.The research leading to these results has received funding from la Caixa Foundation and Caja de Burgos Foundation, under agreement LCF/PR/PR18/51130008 (SS-D, DC, and JR-G

Effects of Nutrition Education Interventions in Team Sport Players. A Systematic Review

Considering nutrition education interventions have been frequently implemented in team sport athletes and have shown promising results, this study aimed to summarize the effects of nutrition education interventions on eating habits, nutrition knowledge, body composition, and physical performance in team sport athletes. A systematic review was conducted using the following databases: PubMed/MEDLINE, Web of Science and SPORTDiscus. A total of 14 studies met the inclusion criteria for the review. The methodological quality of included studies was evaluated, and each study was assessed according to the analyzed variables (i.e., eating habits, nutrition knowledge, body composition, and physical performance). Most studies showed improvements in or maintenance of variables used to indicate eating habits, nutrition knowledge, and body composition. However, limited studies examined the effect of nutrition education interventions on physical performance, with existing studies demonstrating disparate results. These findings suggest implementation of nutrition education interventions in team sport athletes could be an effective strategy to improve their eating habits, nutrition knowledge, and body composition. Due to the heterogeneity across the included studies regarding sport modality, competition level, age, and sex of the athletes investigated, as well as the intervention type adopted (i.e., online or face-to-face), it is difficult to establish optimal nutrition education interventions for each analyzed variable.The research leading to these results has received funding from “la Caixa” Foundation and Caja de Burgos Foundation, under agreement LCF/PR/PR18/51130008

Effects of caffeine, beetroot juice and its interaction consumption on exercise-related fatigue

The aim of this study was to analyze the effect of different supplementation conditions on fatigue and performance in flywheel half-squat tests in senior men. Sixteen active males (age: 22.8±4.9 years; body mass index: 23.7±2.4 kg*m-2) participated in the intervention during a 4-week period. Four experimental conditions were established using a double-blind design: placebo, caffeine (CAF), beetroot juice (BRJ), and combined BRJ+CAF. To assess the effect of supplementation, participants completed a countermovement jump (CMJ) before (Pre), 30 s after (Post-30s) and 180 s after (Post-180 s) completing a flywheel half-squat exercise protocol (four sets of eight all-out repetitions, with a 3-min inter-set rest, using different inertial loads). Additionally, the mean power output during the flywheel half-squat protocol was recorded. A repeated measures ANOVA showed greater mean power (~1000 W, p<.001) produced in flywheel exercise after the CAF, BRJ and BRJ+CAF consumption compared to the placebo condition. After placebo, CAF and BRJ, CMJ performance at Post-180 s was reduced compared to Pre (p=.003-.087, two-way ANOVA; ES=-0.39/-0.49), although no significant performance reduction (p=.087) was noted after BRJ+CAF. In conclusion, compared to placebo, CAF, BRJ, and BRJ+CAF allow greater total mean power in the flywheel half-squat power test, although without effects on exercise-related fatigue. Additionally, BRJ+CAF improved recovery after a high demanding power-production protocol

The effects of defensive style and final game outcome on the external training load of professional basketball players

[EN] This study aimed to analyse the influence of different contextual factors (i.e., defensive style and game outcome) on basketball players’ external load during games-based drills using ultrawideband (UWB) technology. Fourteen male professional basketball players belonging to an elite reserve Spanish club (ACB) participated in this study. The games-based drills consisted of one bout of 10 min played 5vs5 in which players were instructed to use man-to-man defence (MMD) and/or zone defence (ZD). In addition, the final game outcome (i.e., winning or losing) of the game-based drill was registered. External load variables per minute were recorded: total distance covered, distance covered in different speed zones, distance covered while accelerating and decelerating, maximum speed, steps, jumps and player load. A two-way ANOVA with the Tukey post hoc test was used to assess the impact of defensive style and final game outcome and the interaction of both factors on the external load encountered by basketball players. No meaningful differences (unclear) were found in the external loads between playing with MMD and with ZD and between winning and losing teams except for greater distance at high-speed running (18.0–24.0 km·h-1) in winning teams (p < 0.05, ES = 0.68, moderate). A significant interaction between defensive style and final game outcome was found for high decelerations (> -2 m·s-2) (p = 0.041; ES = 0.70) and jumps (p = 0.037; ES = 0.68). These results could potentially help coaching staff in prescribing an appropriate workload during basketball-specific gamebased drills, and ultimately enhance the match performance.The project leading to these results has received funding from “La Caixa” Foundation (ID 100010434) and La Caja de Burgos, under agreement LCF/PR/PR18/51130008Fondo Europeo de Desarrollo Regional (FEDER)] (NARPAS_MM) [SPGC201800X098742CV0]