Search

En el fútbol juvenil, el entrenamiento sistemático de fuerza puede mejorar significativamente el rendimiento. Con frecuencia, este tipo de entrenamiento se lleva a cabo durante el período preparatorio y se interrumpe o reduce su énfasis en el período competitivo. El objetivo del presente estudio fue evaluar la eficacia de tres mesociclos consecutivos de entrenamiento combinado de fuerza (levantamiento de pesas y pliometría en los dos primeros, pliometría y cambios de dirección en el tercero) para lograr mejoras continuas en el rendimiento de sprint, salto vertical y cambios de dirección en jugadores de fútbol juvenil masculino. Dieciocho jugadores de fútbol, con una edad de 14,1 ± 0,3 años y sin experiencia previa en entrenamiento estructurado de fuerza, fueron los sujetos del estudio. Antes y después de cada mesociclo, se evaluó a los deportistas en salto con contramovimiento (CMJ), sprint de 5m, sprint de 10m, sprint de 15m, sprint de 20m y cambio de dirección (test 505). Además, se evaluó el rendimiento en ejercicios específicos utilizados en cada mesociclo, que incluyeron sentadilla, sentadilla búlgara, empuje de cadera unilateral y bilateral, y saltos horizontales unilaterales y bilaterales (simples y múltiples). Se observaron mejoras en el rendimiento en los tres mesociclos para todas las variables analizadas (p ≤ 0,05), excepto para el CMJ (p > 0,05) en el último mesociclo. Dado que las mejoras de rendimiento se lograron con magnitudes de carga relativamente bajas, en comparación con las reportadas en intervenciones similares en esta población, se infiere que esta estrategia tiene el potencial de generar mejoras sostenidas a lo largo de todo el año de entrenamiento en futbolistas jóvenes sin experiencia previa en entrenamiento de fuerza., In youth soccer, systematic resistance training can significantly improve performance. Often, this type of training is carried out during the preparatory season and is interrupted or diminishes its emphasis during the competitive season. The objective of this study was to assess the effectiveness of three consecutive mesocycles of combined resistance training (weightlifting and plyometrics in the first two, plyometrics and changes of direction in the third) to achieve continuous improvements in sprinting, vertical jumps, and changes of direction in male youth soccer players. Eighteen soccer players, with an age of 14.1 ± 0.3 years and no previous experience in structured resistance training, were the subjects of the study. Before and after each mesocycle, athletes were tested in countermovement jump (CMJ), 5m sprint, 10m sprint, 15m sprint, 20m sprint, and change of direction (505 test). Additionally, performance was assessed in specific exercises used in each mesocycle, including squats, Bulgarian squats, unilateral and bilateral hip thrusts, and unilateral and bilateral horizontal jumps (single and multiple). Performance improvements were observed in all analyzed variables across the three mesocycles (p ≤ 0.05), except for CMJ (p > 0.05) in the last mesocycle. Considering that these improvements were attained with relatively low loads compared to those reported in similar interventions with this population, it is inferred that this strategy holds the potential to yield sustained performance enhancements throughout the entire year of training for young soccer players lacking prior experience in resistance training.

In the last twenty years, the youth sport experience in the United States has been shaped by a family’s ability to pay. Under the pay-to-play model in American youth sports, advancing to the highest levels of the game not only requires the standard expenditures, but significant investment which accounts for coaching, equipment, travel, training, and other resources. Previous research on the topic has analyzed the impact of income, educational attainment, and race and ethnicity on access to elite-level sports opportunities. The purpose of this study was to investigate the pay-to-play model and factors associated with athletic outcomes at three youth soccer clubs in southern New Jersey. Additionally, the present research conceptualizes parental motivation at these soccer clubs in relation to a child’s participation and advancement in youth soccer. Multiple linear regression models were used to determine whether there was a significant relationship between athletic opportunity, athletic achievement and parental motivation and a parent’s race/ethnicity, socioeconomic status, and educational attainment levels. For athletic opportunity, the data showed that there was no statistical significance in relation to race/ethnicity, socioeconomic status, or educational attainment. Similarly, no statistically significant findings were present for athletic achievement. For parental motivation, findings indicated that Black or African American parents were 57% more likely to have higher levels of motivation for their child’s participation in club soccer. Motivation was also shaped by parental income.

This case summarizes the rehabilitation and return to play management of a 17-year-old elite male soccer player who required surgical stabilization of an Osteochondritis Dissecans (OCD) lesion of the trochlea groove. Trochlea groove lesions represent <1% of OCD cases, resulting in limited evidence to inform practice. The case was initially identified as antalgic running gait, and at this point the player revealed progressively worsening knee pain (over preceding 2 months) which presented as patellofemoral pain with a small knee effusion and quadriceps atrophy present on assessment. No improvement in symptoms after 2 weeks of unloading (no running) and traditional patellofemoral treatment prompted magnetic resonance imaging and computed tomography scans to inform surgical intervention. We present a summary of the four-stage rehabilitation process defined by objective assessments, resulting in a successful return-to-play 24 weeks post-surgery. This case advocates consideration of OCD in the assessment of persistent knee pain in young athletes.

Objetivo: Calcular el consumo máximo de oxígeno a través de un test de campo submáximo (Yo-Yo de recuperación intermitente I) y valorar la percepción subjetiva del esfuerzo y la percepción del grado de recuperación entre jugadores y sus diferentes posiciones en el campo. Método: 32 jugadores de fútbol masculino de 1ª División Andaluza Sub 15, realizaron el test de campo Yo-Yo de recuperación intermitente I para calcular el consumo máximo de oxígeno, posteriormente se registró la percepción de los esfuerzos y la frecuencia cardíaca. Resultados: Diferentes pruebas t comparando los datos obtenidos mostraron tan sólo diferencias significativas en la frecuencia cardíaca tras recuperación de 1’ entre centrocampistas vs delanteros, t(10)= 3.04, p<0.03, d= 1.18. Además, se encontró una correlación entre los datos promediados de la frecuencia cardíaca a velocidad aeróbica máxima y los datos promediados de la percepción del grado de recuperación. Conclusión: Estos datos indican un mejor comportamiento cardiovascular en los centrocampistas, coincidiendo con lo datos existentes en la literatura., Objective: Calculate the maximum oxygen consumption during physical effort in a submaximal field test (Intermittent Recovery Yo-Yo I) and obtain subjective perception of effort and perception of degree of recovery between the different positions occupied by youth soccer’s on the field. Method: 32 male soccer players from the 1st Andalusian Division U15. The maximum oxygen consumption was calculated using the Intermittent Recovery Yo-Yo I field test, consequently efforts perception and heart rate was recorded. Results: Different t-test comparing the data obtained, only reflected significant differences between midfielders vs. forwards in heart rate after of 1’ recovery, t (10) = 3.04, p<0.03, d=1.18. In addition, we found a positive correlation in heart rate at maximum aerobic velocity and perception of degree of recovery data. Conclusions: The data show a better cardiovascular performance in midfielders coincided with literature.

The purpose of this study focuses on the relationship between parental involvement in sport, support for autonomy, basic psychological needs, motivation and sports commitment, of 208 soccer players over 9 years of age with a mean of 12, 66 years old, applying the Spanish version of the Parental Involvement Sport Questionnaire that assesses the pressure that parents exert on their children, support for autonomy, satisfaction of basic psychological needs, motivation and commitment to sport were also valued current and future; In other words, the influence of social agents in the soccer player's environment was studied: parents, coach and teammates. A reliability, descriptive and bivariate correlation analysis was carried out. The results have shown that the support of the sports environment favors the strengthening of the commitment and development of soccer players, while the pressure increases the possibilities of sports abandonment. Meanwhile support for autonomy develops basic psychological needs, motivation and sports commitment. Just as demotivation is not related to variables such as support for autonomy and sports commitment. Parents are recommended to direct their children's directive behaviors and involvement in sports, improving support and understanding in a way that reduces the perception of pressure from their children; in turn, the coaches provide support for autonomy to ensure sports commitment.

Objetivo: Calcular el consumo máximo de oxígeno a través de un test de campo submáximo (Yo-Yo de recuperación intermitente I) y valorar la percepción subjetiva del esfuerzo y la percepción del grado de recuperación entre jugadores y sus diferentes posiciones en el campo. Método: 32 jugadores de fútbol masculino de 1ª División Andaluza Sub 15, realizaron el test de campo Yo-Yo de recuperación intermitente I para calcular el consumo máximo de oxígeno, posteriormente se registró la percepción de los esfuerzos y la frecuencia cardíaca. Resultados: Diferentes pruebas t comparando los datos obtenidos mostraron tan sólo diferencias significativas en la frecuencia cardíaca tras recuperación de 1’ entre centrocampistas vs delanteros, t(10)= 3.04, p<0.03, d= 1.18. Además, se encontró una correlación entre los datos promediados de la frecuencia cardíaca a velocidad aeróbica máxima y los datos promediados de la percepción del grado de recuperación. Conclusión: Estos datos indican un mejor comportamiento cardiovascular en los centrocampistas, coincidiendo con lo datos existentes en la literatura., Objective: Calculate the maximum oxygen consumption during physical effort in a submaximal field test (Intermittent Recovery Yo-Yo I) and obtain subjective perception of effort and perception of degree of recovery between the different positions occupied by youth soccer’s on the field. Method: 32 male soccer players from the 1st Andalusian Division U15. The maximum oxygen consumption was calculated using the Intermittent Recovery Yo-Yo I field test, consequently efforts perception and heart rate was recorded. Results: Different t-test comparing the data obtained, only reflected significant differences between midfielders vs. forwards in heart rate after of 1’ recovery, t (10) = 3.04, p<0.03, d=1.18. In addition, we found a positive correlation in heart rate at maximum aerobic velocity and perception of degree of recovery data. Conclusions: The data show a better cardiovascular performance in midfielders coincided with literature.

This case summarizes the rehabilitation and return to play management of a 17-year-old elite male soccer player who required surgical stabilization of an Osteochondritis Dissecans (OCD) lesion of the trochlea groove. Trochlea groove lesions represent <1% of OCD cases, resulting in limited evidence to inform practice. The case was initially identified as antalgic running gait, and at this point the player revealed progressively worsening knee pain (over preceding 2 months) which presented as patellofemoral pain with a small knee effusion and quadriceps atrophy present on assessment. No improvement in symptoms after 2 weeks of unloading (no running) and traditional patellofemoral treatment prompted magnetic resonance imaging and computed tomography scans to inform surgical intervention. We present a summary of the four-stage rehabilitation process defined by objective assessments, resulting in a successful return-to-play 24 weeks post-surgery. This case advocates consideration of OCD in the assessment of persistent knee pain in young athletes.

Plyometric jump training (PJT) is a frequently used and effective means to improve amateur and elite soccer players' physical fitness. However, it is unresolved how different PJT frequencies per week with equal overall training volume may affect training-induced adaptations. Therefore, the aim of this study was to compare the effects of an in-season 8 week PJT with one session vs. two sessions per week and equal training volume on components of physical fitness in amateur female soccer players. A single-blind randomized controlled trial was conducted. Participants (N = 23; age, 21.4 +/- 3.2 years) were randomly assigned to a one session PJT per-week (PJT-1, n = 8), two sessions PJT per-week (PJT-2, n = 8) or an active control group (CON, n = 7). Before and after training, participants performed countermovement jumps (CMJ), drop-jumps from a 20-cm drop-height (DJ20), a maximal kicking velocity test (MKV), the 15-m linear sprint-time test, the Meylan test for the assessment of change of direction ability (CoDA), and the Yo-Yo intermittent recovery endurance test (Yo-YoIR1). Results revealed significant main effects of time for the CMJ, DJ20, MKV, 15-m sprint, CoDA, and the Yo-YoIR1 (all p < 0.001; d = 0.57-0.83). Significant group xtime interactions were observed for the CMJ, DJ20, MKV, 15-m sprint, CoDA, and the Yo-YoIR1 (all p < 0.05; d = 0.36-0.51). Post-hoc analyses showed similar improvements for PJT-1 and PJT-2 groups in CMJ (Delta 10.6%, d = 0.37; and Delta 10.1%, d = 0.51, respectively), DJ20 (Delta l2.9%, d = 0.47; and Delta 13.1%, d = 0.54, respectively), MKV (Delta 8.6%, d = 0.52; and Delta 9.1%, d = 0.47, respectively), 15-m sprint (M.3%, d = 2.25; and Delta 9.5%, d = 2.67, respectively), CoDA (Delta 7.5%, d = 1.68; and Delta 7.4%, d = 1.16, respectively), and YoYoIR1 (Delta 10.3%, d = 0.22; and Delta 9.9%, d = 0.26, respectively). No significant pre-post changes were found for CON (all p > 0.05; Delta 0.5-4.2%, d = 0.03-0.2). In conclusion, higher PJT exp

The purpose of this study was to assess the relationship between: Peak oxygen uptake (VO2max) and running economy (RE) with physical measures associated with elite youth soccer performance obtained during soccer match-play. Seventeen highly trained youth soccer players (age: 13.3±0.4y) volunteered to participate. Initially player’s ventilatory threshold (VT) and VO2max was established using a treadmill protocol. On the subsequent visit, players ran for 4 min, at three different speeds (8km/h, 80%VT and 95%VT). Physical soccer-based performance was assessed using a maximal Yo-Yo IR1 and via Global positioning systems (GPS) derived variables obtained during three, 2x20min, 11 v 11 soccer matches. Partial correlations revealed significant relationships between relative VO2max and measures of physical soccer performance (r = 0.54–0.88). Moreover, measures of ventilatory equivalent (VEVO2), a determinant of RE, at all sub-maximal exercise intensities were inversely related to the volume (m) and percentage (%) of very high intensity activities. Current findings emphasise the need for high levels of cardio-respiratory fitness in high level youth soccer players, with superior levels of fitness being associated with a greater amount of high and very high intensity activity during soccer match-play.

Aim The main purpose of this study was to investigate and compare the effects of a very heavy resisted sprint training regimen and a unresisted sprint training regimen on sprint, acceleration and jump performance in late pubertal adolescent football (soccer) players at mid- to post-PHV and >95% PAH. Method In total 27 male football players were recruited as volunteer participants. The participants had no previous experience with resisted sprint training. The participants were randomly assigned to either the resisted sprint (RST) (n=9) or unresisted sprint (UST) (n=10) training group. However, the grouping was matched based on the force-velocity (F-v) profiling. A control group (i.e. TAU group n=8) was matched with the experimental groups based on age and anthropometrics. The training was done twice a week for four weeks, consisting of either resisted or unresisted sprints. 24 of the original 27 participants could later be included for statistical analysis. During intervention the TAU group performed the regular team training with no additional stimuli from the researchers. Anthropometrics, sprint, acceleration and jump performance testing was tested pre- and post-training intervention. Results The four-week training intervention resulted in significant improvements of sprint- and acceleration for the RST-group. The improvements were 3,8% (±0.05) in T30, 4,2% (±0.06) in T20, 5,7% (±0.06) in T10, and 7,9% (±0.06) in the T5. The RST and UST groups also had significant improvements in both vertical and horizontal jump performance. Further there were several significant between group changes in both sprint and jump performance favoring the RST group over both the UST and TAU groups. Conclusion The conclusions are that in this population a very heavy RST regimen elicits improvements in sprint and acceleration performance whilst a UST regimen does not. Further, both the RST- and UST- training regimens elicit improvements in both vertical and horizontal jump per, Abstrakt Syfte Det huvudsakliga syftet med denna studie var att undersöka och jämföra effekterna av väldigt tungt belastad sprintträning och obelastad sprintträning på sprint-, acceleration och hopprestation hos unga fotbollsspelare i sena tonåren som ligger på en mognadsgrad av ”mid- post-PHV” samt >95% PAH. Metod Totalt 27 fotbollsspelare rekryterades som frivilliga deltagare. Deltagarna hade ingen tidigare erfarenhet av belastad sprintträning. Deltagarna blev slumpmässigt indelade till antingen den belastade (RST) eller den obelastade (UST) träningsgruppen. Dock skedde grupperingen med deltagarnas kraft- hastighetsprofilering som bas, då grupperna blev matchade efter denna. Kontrollgruppen (TAU n=8) matchades med experimentgrupperna efter ålder och antropometri. Träningen bestod av väldigt tungt belastad eller obelastad sprintträning och utfördes två gånger i veckan under fyra veckor. 24 av de initialt 27 deltagarna kunde inkluderas för vidare analys. Under interventionen genomförde TAU den vanliga lagträningen utan ytterligare träningsstimuli från forskarna. Antropometri, sprint, acceleration och hopprestation testades före respektive efter interventionen. Resultat Den fyra veckor långa träningsinterventionen resulterade i signifikanta förbättringar i sprint och acceleration för RST-gruppen. Förbättringarna var 3,8% (±0.05) i T30, 4,2% (±0.06) i T20, 5,7% (±0.06) i T10, och 7,9% (±0.06) i T5. RST och UST grupperna hade också signifikanta förbättringar i både vertikal och horisontell hopprestation. Vidare fanns det flera signifikanta mellangruppsskillnader i både sprint- och hopprestation till fördel för RST gruppen över både UST och TAU grupperna. Konklusion Konklusionen är att ett väldigt tungt RST-träningsprogram framkallar signifikanta förbättringar i både sprint, acceleration och hopprestation medan ett UST-träningsprogram inte gör det. Vidare kan konkluderas att både ett RST- och ett UST-träningsprogram

Plyometric jump training (PJT) is a frequently used and effective means to improve amateur and elite soccer players' physical fitness. However, it is unresolved how different PJT frequencies per week with equal overall training volume may affect training-induced adaptations. Therefore, the aim of this study was to compare the effects of an in-season 8 week PJT with one session vs. two sessions per week and equal training volume on components of physical fitness in amateur female soccer players. A single-blind randomized controlled trial was conducted. Participants (N = 23; age, 21.4 +/- 3.2 years) were randomly assigned to a one session PJT per-week (PJT-1, n = 8), two sessions PJT per-week (PJT-2, n = 8) or an active control group (CON, n = 7). Before and after training, participants performed countermovement jumps (CMJ), drop-jumps from a 20-cm drop-height (DJ20), a maximal kicking velocity test (MKV), the 15-m linear sprint-time test, the Meylan test for the assessment of change of direction ability (CoDA), and the Yo-Yo intermittent recovery endurance test (Yo-YoIR1). Results revealed significant main effects of time for the CMJ, DJ20, MKV, 15-m sprint, CoDA, and the Yo-YoIR1 (all p < 0.001; d = 0.57-0.83). Significant group xtime interactions were observed for the CMJ, DJ20, MKV, 15-m sprint, CoDA, and the Yo-YoIR1 (all p < 0.05; d = 0.36-0.51). Post-hoc analyses showed similar improvements for PJT-1 and PJT-2 groups in CMJ (Delta 10.6%, d = 0.37; and Delta 10.1%, d = 0.51, respectively), DJ20 (Delta l2.9%, d = 0.47; and Delta 13.1%, d = 0.54, respectively), MKV (Delta 8.6%, d = 0.52; and Delta 9.1%, d = 0.47, respectively), 15-m sprint (M.3%, d = 2.25; and Delta 9.5%, d = 2.67, respectively), CoDA (Delta 7.5%, d = 1.68; and Delta 7.4%, d = 1.16, respectively), and YoYoIR1 (Delta 10.3%, d = 0.22; and Delta 9.9%, d = 0.26, respectively). No significant pre-post changes were found for CON (all p > 0.05; Delta 0.5-4.2%, d = 0.03-0.2). In conclusion, higher PJT exp

Aim The main purpose of this study was to investigate and compare the effects of a very heavy resisted sprint training regimen and a unresisted sprint training regimen on sprint, acceleration and jump performance in late pubertal adolescent football (soccer) players at mid- to post-PHV and >95% PAH. Method In total 27 male football players were recruited as volunteer participants. The participants had no previous experience with resisted sprint training. The participants were randomly assigned to either the resisted sprint (RST) (n=9) or unresisted sprint (UST) (n=10) training group. However, the grouping was matched based on the force-velocity (F-v) profiling. A control group (i.e. TAU group n=8) was matched with the experimental groups based on age and anthropometrics. The training was done twice a week for four weeks, consisting of either resisted or unresisted sprints. 24 of the original 27 participants could later be included for statistical analysis. During intervention the TAU group performed the regular team training with no additional stimuli from the researchers. Anthropometrics, sprint, acceleration and jump performance testing was tested pre- and post-training intervention. Results The four-week training intervention resulted in significant improvements of sprint- and acceleration for the RST-group. The improvements were 3,8% (±0.05) in T30, 4,2% (±0.06) in T20, 5,7% (±0.06) in T10, and 7,9% (±0.06) in the T5. The RST and UST groups also had significant improvements in both vertical and horizontal jump performance. Further there were several significant between group changes in both sprint and jump performance favoring the RST group over both the UST and TAU groups. Conclusion The conclusions are that in this population a very heavy RST regimen elicits improvements in sprint and acceleration performance whilst a UST regimen does not. Further, both the RST- and UST- training regimens elicit improvements in both vertical and horizontal jump per, Abstrakt Syfte Det huvudsakliga syftet med denna studie var att undersöka och jämföra effekterna av väldigt tungt belastad sprintträning och obelastad sprintträning på sprint-, acceleration och hopprestation hos unga fotbollsspelare i sena tonåren som ligger på en mognadsgrad av ”mid- post-PHV” samt >95% PAH. Metod Totalt 27 fotbollsspelare rekryterades som frivilliga deltagare. Deltagarna hade ingen tidigare erfarenhet av belastad sprintträning. Deltagarna blev slumpmässigt indelade till antingen den belastade (RST) eller den obelastade (UST) träningsgruppen. Dock skedde grupperingen med deltagarnas kraft- hastighetsprofilering som bas, då grupperna blev matchade efter denna. Kontrollgruppen (TAU n=8) matchades med experimentgrupperna efter ålder och antropometri. Träningen bestod av väldigt tungt belastad eller obelastad sprintträning och utfördes två gånger i veckan under fyra veckor. 24 av de initialt 27 deltagarna kunde inkluderas för vidare analys. Under interventionen genomförde TAU den vanliga lagträningen utan ytterligare träningsstimuli från forskarna. Antropometri, sprint, acceleration och hopprestation testades före respektive efter interventionen. Resultat Den fyra veckor långa träningsinterventionen resulterade i signifikanta förbättringar i sprint och acceleration för RST-gruppen. Förbättringarna var 3,8% (±0.05) i T30, 4,2% (±0.06) i T20, 5,7% (±0.06) i T10, och 7,9% (±0.06) i T5. RST och UST grupperna hade också signifikanta förbättringar i både vertikal och horisontell hopprestation. Vidare fanns det flera signifikanta mellangruppsskillnader i både sprint- och hopprestation till fördel för RST gruppen över både UST och TAU grupperna. Konklusion Konklusionen är att ett väldigt tungt RST-träningsprogram framkallar signifikanta förbättringar i både sprint, acceleration och hopprestation medan ett UST-träningsprogram inte gör det. Vidare kan konkluderas att både ett RST- och ett UST-träningsprogram

Plyometric jump training (PJT) is a frequently used and effective means to improve amateur and elite soccer players' physical fitness. However, it is unresolved how different PJT frequencies per week with equal overall training volume may affect training-induced adaptations. Therefore, the aim of this study was to compare the effects of an in-season 8 week PJT with one session vs. two sessions per week and equal training volume on components of physical fitness in amateur female soccer players. A single-blind randomized controlled trial was conducted. Participants (N = 23; age, 21.4 +/- 3.2 years) were randomly assigned to a one session PJT per-week (PJT-1, n = 8), two sessions PJT per-week (PJT-2, n = 8) or an active control group (CON, n = 7). Before and after training, participants performed countermovement jumps (CMJ), drop-jumps from a 20-cm drop-height (DJ20), a maximal kicking velocity test (MKV), the 15-m linear sprint-time test, the Meylan test for the assessment of change of direction ability (CoDA), and the Yo-Yo intermittent recovery endurance test (Yo-YoIR1). Results revealed significant main effects of time for the CMJ, DJ20, MKV, 15-m sprint, CoDA, and the Yo-YoIR1 (all p < 0.001; d = 0.57-0.83). Significant group xtime interactions were observed for the CMJ, DJ20, MKV, 15-m sprint, CoDA, and the Yo-YoIR1 (all p < 0.05; d = 0.36-0.51). Post-hoc analyses showed similar improvements for PJT-1 and PJT-2 groups in CMJ (Delta 10.6%, d = 0.37; and Delta 10.1%, d = 0.51, respectively), DJ20 (Delta l2.9%, d = 0.47; and Delta 13.1%, d = 0.54, respectively), MKV (Delta 8.6%, d = 0.52; and Delta 9.1%, d = 0.47, respectively), 15-m sprint (M.3%, d = 2.25; and Delta 9.5%, d = 2.67, respectively), CoDA (Delta 7.5%, d = 1.68; and Delta 7.4%, d = 1.16, respectively), and YoYoIR1 (Delta 10.3%, d = 0.22; and Delta 9.9%, d = 0.26, respectively). No significant pre-post changes were found for CON (all p > 0.05; Delta 0.5-4.2%, d = 0.03-0.2). In conclusion, higher PJT exp

The purpose of this study was to assess the relationship between: Peak oxygen uptake (VO2max) and running economy (RE) with physical measures associated with elite youth soccer performance obtained during soccer match-play. Seventeen highly trained youth soccer players (age: 13.3±0.4y) volunteered to participate. Initially player’s ventilatory threshold (VT) and VO2max was established using a treadmill protocol. On the subsequent visit, players ran for 4 min, at three different speeds (8km/h, 80%VT and 95%VT). Physical soccer-based performance was assessed using a maximal Yo-Yo IR1 and via Global positioning systems (GPS) derived variables obtained during three, 2x20min, 11 v 11 soccer matches. Partial correlations revealed significant relationships between relative VO2max and measures of physical soccer performance (r = 0.54–0.88). Moreover, measures of ventilatory equivalent (VEVO2), a determinant of RE, at all sub-maximal exercise intensities were inversely related to the volume (m) and percentage (%) of very high intensity activities. Current findings emphasise the need for high levels of cardio-respiratory fitness in high level youth soccer players, with superior levels of fitness being associated with a greater amount of high and very high intensity activity during soccer match-play.

Doncaster, G and Unnithan, V. Between-game variation of physical soccer performance measures in highly trained youth soccer players. J Strength Cond Res 33(7): 1912-1920, 2019-To assess the between-game variation in measures of physical performance during 11 vs. 11 soccer match play, over a short period, in highly trained youth soccer players. A single-cohort, observational, study design was used. Physical match performance data were collected from 17, male, highly trained, youth soccer players (age, 13.3 ± 0.4 years) over 3, 2 × 20 minutes, 11 vs. 11 matches. Using 10-Hz global positioning systems, the variables selected for analyses were total distance (TD), high-speed running (HSR), very high-speed running (VHSR), number of high-speed running efforts (HSReff), and number of very high-speed running efforts (VHSReff). Match data were also separated into cumulative 5-minute epochs, to identify the peak 5-minute epoch and the mean of the cumulative 5-minute epochs for each match. Variability was quantified using the coefficient of variation (CV), standard error of measurement, and intraclass correlation coefficient. Between- and within-player smallest worthwhile changes (SWC) were also calculated for each variable to aid in the interpretation of the data. Analysis of the variance between games reported a low CV for TD (3.8%) but larger CVs for HSR (33.3%), HSReff (35.4%), and VHSR and VHSReff (59.6 and 57.4%, respectively). Analysis of 5-minute epochs (peak and average) found an increase in the CVs beyond that of the values reported for the whole match. Between-player SWC in high-intensity physical performance data ranged from 24.7 to 42.4%, whereas within-player SWC ranged from 1.2 to 79.9%. The between-game variability of high-intensity and very high-intensity activities in youth soccer players, across 3 soccer matches over a short period (2 weeks), is relatively "large" and specific to the individual, thus highlighting the need for caution when interpreting phy

Doncaster, G and Unnithan, V. Between-game variation of physical soccer performance measures in highly trained youth soccer players. J Strength Cond Res 33(7): 1912-1920, 2019-To assess the between-game variation in measures of physical performance during 11 vs. 11 soccer match play, over a short period, in highly trained youth soccer players. A single-cohort, observational, study design was used. Physical match performance data were collected from 17, male, highly trained, youth soccer players (age, 13.3 ± 0.4 years) over 3, 2 × 20 minutes, 11 vs. 11 matches. Using 10-Hz global positioning systems, the variables selected for analyses were total distance (TD), high-speed running (HSR), very high-speed running (VHSR), number of high-speed running efforts (HSReff), and number of very high-speed running efforts (VHSReff). Match data were also separated into cumulative 5-minute epochs, to identify the peak 5-minute epoch and the mean of the cumulative 5-minute epochs for each match. Variability was quantified using the coefficient of variation (CV), standard error of measurement, and intraclass correlation coefficient. Between- and within-player smallest worthwhile changes (SWC) were also calculated for each variable to aid in the interpretation of the data. Analysis of the variance between games reported a low CV for TD (3.8%) but larger CVs for HSR (33.3%), HSReff (35.4%), and VHSR and VHSReff (59.6 and 57.4%, respectively). Analysis of 5-minute epochs (peak and average) found an increase in the CVs beyond that of the values reported for the whole match. Between-player SWC in high-intensity physical performance data ranged from 24.7 to 42.4%, whereas within-player SWC ranged from 1.2 to 79.9%. The between-game variability of high-intensity and very high-intensity activities in youth soccer players, across 3 soccer matches over a short period (2 weeks), is relatively "large" and specific to the individual, thus highlighting the need for caution when interpreting phy

The aim of the present study is to analyse the influence of different large-sided games (LSGs) on the physical and physiological variables in under-12s (U12) and -13s (U13) soccer players. The effects of the combination of different number of players per team, 7, 9, and 11 (P7, P9, and P11, respectively) with three relative pitch areas, 100, 200, and 300 m(2) (A100, A200, and A300, respectively), were analysed in this study. The variables analysed were: 1) global indicator such as total distance (TD); work:rest ratio (W:R); player-load (PL) and maximal speed (V-max); 2) heart rate (HR) mean and time spent in different intensity zones of HR (<75%, 75-84%, 84-90% and >90%), and; 3) five absolute (<8, 8-13, 13-16 and >16 Km h(-1)) and three relative speed categories (<40%, 40-60% and >60% V-max). The results support the theory that a change in format (player number and pitch dimensions) affects no similarly in the two players categories. Although it can seem that U13 players are more demanded in this kind of LSG, when the work load is assessed from a relative point of view, great pitch dimensions and/or high number of player per team are involved in the training task to the U12 players. The results of this study could alert to the coaches to avoid some types of LSGs for the U12 players such as:P11 played in A100, A200 or A300, P9 played in A200 or A300 and P7 played in A300 due to that U13>U12 in several physical and physiological variables (W:R, time spent in 84-90% HRmax, distance in 8-13 and 13-16 Km h(-1) and time spent in 40-60% V-max). These results may help youth soccer coaches to plan the progressive introduction of LSGs so that task demands are adapted to the physiological and physical development of participants.

Purpose: To examine the relationship between oxygen uptake kinetics (VO 2 kinetics) and physical measures associated with soccer match play, within a group of highly trained youth soccer players. Methods: Seventeen highly trained youth soccer players (age: 13.3 ± 0.4 year, self-assessed Tanner stage: 3 ± 1) volunteered for the study. Players initially completed an incremental treadmill protocol to exhaustion, to establish gaseous exchange threshold (GET) and VO 2max (59.1 ± 5.4 mL kg −1 min −1). On subsequent visits, players completed a step transition protocol from rest–moderate-intensity exercise, followed by an immediate transition, and from moderate- to severe-intensity exercise (moderate: 95 % GET, severe: 60 %∆), during which VO 2 kinetics were determined. Physical soccer-based performance was assessed using a maximal Yo–Yo intermittent recovery test level 1 (Yo–Yo IR1) and via GPS-derived measures of physical soccer performance during soccer match play, three 2 × 20 min, 11 v 11 matches, to gain measures of physical performance during soccer match play. Results: Partial correlations revealed significant inverse relationships between the unloaded-to-moderate transition time constant (tau) and: Yo–Yo IR1 performance (r = −0.58, P = 0.02) and GPS variables [total distance (TD): r = −0.64, P = 0.007, high-speed running (HSR): r = −0.64, P = 0.008 and high-speed running efforts (HSReff): r = −0.66, P = 0.005]. Conclusion: Measures of VO 2 kinetics are related to physical measures associated with soccer match play and could potentially be used to distinguish between those of superior physical performance, within a group of highly trained youth soccer players.

The aim of the present study is to analyse the influence of different large-sided games (LSGs) on the physical and physiological variables in under-12s (U12) and -13s (U13) soccer players. The effects of the combination of different number of players per team, 7, 9, and 11 (P7, P9, and P11, respectively) with three relative pitch areas, 100, 200, and 300 m(2) (A100, A200, and A300, respectively), were analysed in this study. The variables analysed were: 1) global indicator such as total distance (TD); work:rest ratio (W:R); player-load (PL) and maximal speed (V-max); 2) heart rate (HR) mean and time spent in different intensity zones of HR (<75%, 75-84%, 84-90% and >90%), and; 3) five absolute (<8, 8-13, 13-16 and >16 Km h(-1)) and three relative speed categories (<40%, 40-60% and >60% V-max). The results support the theory that a change in format (player number and pitch dimensions) affects no similarly in the two players categories. Although it can seem that U13 players are more demanded in this kind of LSG, when the work load is assessed from a relative point of view, great pitch dimensions and/or high number of player per team are involved in the training task to the U12 players. The results of this study could alert to the coaches to avoid some types of LSGs for the U12 players such as:P11 played in A100, A200 or A300, P9 played in A200 or A300 and P7 played in A300 due to that U13>U12 in several physical and physiological variables (W:R, time spent in 84-90% HRmax, distance in 8-13 and 13-16 Km h(-1) and time spent in 40-60% V-max). These results may help youth soccer coaches to plan the progressive introduction of LSGs so that task demands are adapted to the physiological and physical development of participants.

The aim of the present study is to analyse the influence of different large-sided games (LSGs) on the physical and physiological variables in under-12s (U12) and -13s (U13) soccer players. The effects of the combination of different number of players per team, 7, 9, and 11 (P7, P9, and P11, respectively) with three relative pitch areas, 100, 200, and 300 m(2) (A100, A200, and A300, respectively), were analysed in this study. The variables analysed were: 1) global indicator such as total distance (TD); work:rest ratio (W:R); player-load (PL) and maximal speed (V-max); 2) heart rate (HR) mean and time spent in different intensity zones of HR (<75%, 75-84%, 84-90% and >90%), and; 3) five absolute (<8, 8-13, 13-16 and >16 Km h(-1)) and three relative speed categories (<40%, 40-60% and >60% V-max). The results support the theory that a change in format (player number and pitch dimensions) affects no similarly in the two players categories. Although it can seem that U13 players are more demanded in this kind of LSG, when the work load is assessed from a relative point of view, great pitch dimensions and/or high number of player per team are involved in the training task to the U12 players. The results of this study could alert to the coaches to avoid some types of LSGs for the U12 players such as:P11 played in A100, A200 or A300, P9 played in A200 or A300 and P7 played in A300 due to that U13>U12 in several physical and physiological variables (W:R, time spent in 84-90% HRmax, distance in 8-13 and 13-16 Km h(-1) and time spent in 40-60% V-max). These results may help youth soccer coaches to plan the progressive introduction of LSGs so that task demands are adapted to the physiological and physical development of participants.

Purpose: To examine the relationship between oxygen uptake kinetics (VO 2 kinetics) and physical measures associated with soccer match play, within a group of highly trained youth soccer players. Methods: Seventeen highly trained youth soccer players (age: 13.3 ± 0.4 year, self-assessed Tanner stage: 3 ± 1) volunteered for the study. Players initially completed an incremental treadmill protocol to exhaustion, to establish gaseous exchange threshold (GET) and VO 2max (59.1 ± 5.4 mL kg −1 min −1). On subsequent visits, players completed a step transition protocol from rest–moderate-intensity exercise, followed by an immediate transition, and from moderate- to severe-intensity exercise (moderate: 95 % GET, severe: 60 %∆), during which VO 2 kinetics were determined. Physical soccer-based performance was assessed using a maximal Yo–Yo intermittent recovery test level 1 (Yo–Yo IR1) and via GPS-derived measures of physical soccer performance during soccer match play, three 2 × 20 min, 11 v 11 matches, to gain measures of physical performance during soccer match play. Results: Partial correlations revealed significant inverse relationships between the unloaded-to-moderate transition time constant (tau) and: Yo–Yo IR1 performance (r = −0.58, P = 0.02) and GPS variables [total distance (TD): r = −0.64, P = 0.007, high-speed running (HSR): r = −0.64, P = 0.008 and high-speed running efforts (HSReff): r = −0.66, P = 0.005]. Conclusion: Measures of VO 2 kinetics are related to physical measures associated with soccer match play and could potentially be used to distinguish between those of superior physical performance, within a group of highly trained youth soccer players.

The purpose of this study was to compare the effects of Small-Sided Games (SSG) vs. Interval Training (IT) in soccer training on aerobic fitness and physical enjoyment in youth elite soccer players during the last 8 weeks of the season. Seventeen U-16 male soccer players (age = 15.5 +/- 0.6 years, and 8.5 years of experience) of a Spanish First Division club academy were randomized to 2 different groups for 6 weeks: SSG group (n = 9) and IT group (n = 8). In addition to the usual technical and tactical sessions and competitive games, the SSG group performed 11 sessions with different SSGs, whereas the IT group performed the same number of sessions of IT. Players were tested before and after the 6-week training intervention with a continuous maximal multistage running field test and the counter movement jump test (CMJ). At the end of the study, players answered the physical activity enjoyment scale (PACES). During the study, heart rate (HR) and session perceived effort (sRPE) were assessed. SSGs were as effective as IT in maintaining the aerobic fitness in elite young soccer players during the last weeks of the season. Players in the SSG group declared a greater physical enjoyment than IT (P = 0.006; ES = 1.86 +/- 1.07). Coaches could use SSG training during the last weeks of the season as an option without fear of losing aerobic fitness while promoting high physical enjoyment.

314 p., The aim of the present study was to determine anthropometric, physical and physiological characteristics of high level players, to analyze how these parameters change across time and to determine their relevance in the selection process of a professional soccer club. The study involves a longitudinal analysis during 4 competitive seasons of young soccer players of the Athletic Club of Bilbao that were evaluated annually on two occasions. Anthropometry, physical performance tests, salivary hormones concentration, chronological age and age at peak height velocity were measured. We observed that as players get older they grew and performed better. However, results indicate that changes in performance were significantly affected by growth and maturation. Thus, the patterns of physical growth and maturation of young players merit more detailed consideration. Besides, it seems clear that a large body size and a small amount of body fat are relevant anthropometric parameters involved in the selection process of high level soccer players. Moreover, we observed that anthropometrical and physical performance characteristics can differentiate between players that are selected from those that are not. Also, results demonstrate that these procedures may eliminate late maturer’s with potential and exclude players born late. Finally, it seems that technical staff of the club selects players with a large body size, advanced maturity, and particularly older chronological age and less body fat.

The purpose of this study was to compare the effects of Small-Sided Games (SSG) vs. Interval Training (IT) in soccer training on aerobic fitness and physical enjoyment in youth elite soccer players during the last 8 weeks of the season. Seventeen U-16 male soccer players (age = 15.5 +/- 0.6 years, and 8.5 years of experience) of a Spanish First Division club academy were randomized to 2 different groups for 6 weeks: SSG group (n = 9) and IT group (n = 8). In addition to the usual technical and tactical sessions and competitive games, the SSG group performed 11 sessions with different SSGs, whereas the IT group performed the same number of sessions of IT. Players were tested before and after the 6-week training intervention with a continuous maximal multistage running field test and the counter movement jump test (CMJ). At the end of the study, players answered the physical activity enjoyment scale (PACES). During the study, heart rate (HR) and session perceived effort (sRPE) were assessed. SSGs were as effective as IT in maintaining the aerobic fitness in elite young soccer players during the last weeks of the season. Players in the SSG group declared a greater physical enjoyment than IT (P = 0.006; ES = 1.86 +/- 1.07). Coaches could use SSG training during the last weeks of the season as an option without fear of losing aerobic fitness while promoting high physical enjoyment.

314 p., The aim of the present study was to determine anthropometric, physical and physiological characteristics of high level players, to analyze how these parameters change across time and to determine their relevance in the selection process of a professional soccer club. The study involves a longitudinal analysis during 4 competitive seasons of young soccer players of the Athletic Club of Bilbao that were evaluated annually on two occasions. Anthropometry, physical performance tests, salivary hormones concentration, chronological age and age at peak height velocity were measured. We observed that as players get older they grew and performed better. However, results indicate that changes in performance were significantly affected by growth and maturation. Thus, the patterns of physical growth and maturation of young players merit more detailed consideration. Besides, it seems clear that a large body size and a small amount of body fat are relevant anthropometric parameters involved in the selection process of high level soccer players. Moreover, we observed that anthropometrical and physical performance characteristics can differentiate between players that are selected from those that are not. Also, results demonstrate that these procedures may eliminate late maturer’s with potential and exclude players born late. Finally, it seems that technical staff of the club selects players with a large body size, advanced maturity, and particularly older chronological age and less body fat.

The purpose of this study was to compare the effects of Small-Sided Games (SSG) vs. Interval Training (IT) in soccer training on aerobic fitness and physical enjoyment in youth elite soccer players during the last 8 weeks of the season. Seventeen U-16 male soccer players (age = 15.5 +/- 0.6 years, and 8.5 years of experience) of a Spanish First Division club academy were randomized to 2 different groups for 6 weeks: SSG group (n = 9) and IT group (n = 8). In addition to the usual technical and tactical sessions and competitive games, the SSG group performed 11 sessions with different SSGs, whereas the IT group performed the same number of sessions of IT. Players were tested before and after the 6-week training intervention with a continuous maximal multistage running field test and the counter movement jump test (CMJ). At the end of the study, players answered the physical activity enjoyment scale (PACES). During the study, heart rate (HR) and session perceived effort (sRPE) were assessed. SSGs were as effective as IT in maintaining the aerobic fitness in elite young soccer players during the last weeks of the season. Players in the SSG group declared a greater physical enjoyment than IT (P = 0.006; ES = 1.86 +/- 1.07). Coaches could use SSG training during the last weeks of the season as an option without fear of losing aerobic fitness while promoting high physical enjoyment.

314 p., The aim of the present study was to determine anthropometric, physical and physiological characteristics of high level players, to analyze how these parameters change across time and to determine their relevance in the selection process of a professional soccer club. The study involves a longitudinal analysis during 4 competitive seasons of young soccer players of the Athletic Club of Bilbao that were evaluated annually on two occasions. Anthropometry, physical performance tests, salivary hormones concentration, chronological age and age at peak height velocity were measured. We observed that as players get older they grew and performed better. However, results indicate that changes in performance were significantly affected by growth and maturation. Thus, the patterns of physical growth and maturation of young players merit more detailed consideration. Besides, it seems clear that a large body size and a small amount of body fat are relevant anthropometric parameters involved in the selection process of high level soccer players. Moreover, we observed that anthropometrical and physical performance characteristics can differentiate between players that are selected from those that are not. Also, results demonstrate that these procedures may eliminate late maturer’s with potential and exclude players born late. Finally, it seems that technical staff of the club selects players with a large body size, advanced maturity, and particularly older chronological age and less body fat.

Literature underscores the complex role of coaches in sport organizations, especially in youth sectors. Their need for support, not only on the technical level, is emerging. In recent years an interesting international debate has evolved regarding what education is most suitable to support coach development. The article intends to enter this debate by proposing an educational model for youth soccer coaches. This educational proposal is the outcome of reflection that originated from various experiences with about 110 Italian youth soccer coaches over the past six years. The first part is dedicated to a review of the literature on coaching education, and the second to the educational model presented (e.g., theoretical background, characteristics, setting, outcomes, and considerations regarding the management of this educational process). The strength of this model was precisely to have put some recurrent issues in dialogue with the specific organizational contexts in which the educational programs were implemented.

The purpose of this research was to assess relationships between subjective and external measures of training load in professional youth footballers, whilst accounting for the effect of the stage of the season. Data for ratings of perceived exertion (RPE) and seven global positioning systems (GPS) derived measures were collected from 20 players (age=17.4±1.3yrs, height=178.0±8.1 cm, mass=71.8±7.2 kg) across a 47-week season. The season was categorised by a pre-season phase, and two competitive phases (Comp1, Comp2). The structure of the data were investigated using principal component analysis. An extraction criterion of component with eigenvalues ≥1.0 was used. Two components were retained for the pre-season period explaining a cumulative variance of 77.1%. Single components were retained for both Comp1 and Comp2 explaining 73.3% and 74.3% of variance, respectively. Identification of single components may suggest that measures are related and can be used interchangeably, however these interpretations should be considered with caution. The identification of multiple components in the pre-season phase suggests that univariate measures may not be sufficient when considering load experienced. These results suggest that factoring load based on measures of volume and intensity should be considered.

Einleitung: Fußball gehört zu den Sportarten mit den höchsten Verletzungsraten. Bereits im Nachwuchsfußball werden hohe Verletzungsraten der unteren Extremität registriert. Mittlerweile haben zahlreiche wissenschaftliche Untersuchungen Risikofaktoren für Sportverletzungen evaluiert. Forschungsergebnisse zeigten, dass Asymmetrien der Extremitäten in Kraft- oder koordinativen Fähigkeiten einen modifizierbaren Risikofaktor für Verletzungen der unteren Extremität darstellen. Außerdem identifizierten Studien einheitlich die Verletzungshistorie als einen starken Risikofaktor für Verletzungen gleicher oder anderer Art. Zusätzlich wurden stärkere Asymmetrien der Extremitäten nach Verletzungen der unteren Extremität festgestellt. Es gibt aktuell wenig bekannte Studien, die sich mit den Auswirkungen von Verletzungen auf die Beinsymmetrie bei Nachwuchsfußballern befasst haben. Außerdem gibt es nach aktuellem Kenntnisstand nur wenige Untersuchungen zu Veränderungen von Asymmetrien bei Nachwuchsfußballern unterschiedlicher Altersklassen. Zielsetzung: Daher war das Ziel dieser Masterarbeit zu untersuchen, inwiefern sich eine vorherige Verletzung in der Rückrunde der letzten Saison bei Nachwuchsfußballern auf die Beinsymmetrie in Kraft- und koordinativen Tests auswirkt. Ein weiteres Ziel dieser Arbeit war es zu prüfen, ob es Unterschiede in der Beinsymmetrie bei Nachwuchsfußballern unterschiedlicher Altersklassen gibt. Methodik: Es handelte sich um eine retrospektive Analyse. Die Verletzungen der Nachwuchsspieler der Tiroler Akademie der Rückrunde der letzten Saison wurden evaluiert. Insgesamt nahmen 59 Spieler der U15, U16 und U18 im Alter von 14-17 Jahren an der Untersuchung teil. Mittels einer Testbatterie aus 6 verschiedenen Kraft- und Koordination Tests wurde die Beinsymmetrie (Limb Symmetrie Index) der Spieler in der Vorbereitung der Saison analysiert. Es wurden folgende Testverfahren angewendet: Y-Balance Test (YBT), Single-Leg Hop (SLH), einbeiniger Stability Test (ST), is, Introduction: Soccer has one of the highest injury rates in all sports. High injury rates of the lower extremity have also been reported in elite youth soccer players. Recently, risk factors for sports injury have been investigated in many studies. Research indicates that greater asymmetry in lower body functional performance displays a modifiable risk factor. In addition, a previous injury has been identified as another strong risk factor for a subsequent lower limb injury. In this context, greater asymmetries have been reported in athletes after injuries. Currently, there is a lack of evidence about the impact of lower limb injuries on leg symmetry in youth soccer players. Moreover, only few studies have evaluated the effect of maturation on leg symmetry in youth athletes. Objective: Therefore, the aim of this study was to investigate the impact of a previous lower limb injury on lower limb symmetry in strength related and coordination related tasks in elite youth soccer players. Another aim was to evaluate the effect of age on leg symmetry in three different age groups. Methods: This study was a retrospective analysis. All injuries of the players of the Tyrolean youth soccer academy in the second half of the last season have been analyzed. 59 players of three age groups (U15, U16, U18) with the age of 14-17 years participated in this study. A screening battery, consisting of 6 different tests (coordination and strength related) was used to determine the leg symmetry (limb symmetry index). The following test were applied: Y- Balance Test (YBT), single-leg hop (SLH), one-leg stability Test (ST), one-leg isometric press strength test (ILT), one-leg isometric knee flexion test (HISO), Nordic Hamstring Exercise (NHE). A linear regression analysis was conducted to examine if a previous injury displays a predictor for leg symmetry. Furthermore, differences in leg symmetry between the age groups were examined. The level of significance was set at p<0.05. Results: 41 inju, eingereicht von BSc, BSc Sven Hansen, in englischer Sprache, Masterarbeit Universität Innsbruck 2021

Einleitung: Fußball gehört zu den Sportarten mit den höchsten Verletzungsraten. Bereits im Nachwuchsfußball werden hohe Verletzungsraten der unteren Extremität registriert. Mittlerweile haben zahlreiche wissenschaftliche Untersuchungen Risikofaktoren für Sportverletzungen evaluiert. Forschungsergebnisse zeigten, dass Asymmetrien der Extremitäten in Kraft- oder koordinativen Fähigkeiten einen modifizierbaren Risikofaktor für Verletzungen der unteren Extremität darstellen. Außerdem identifizierten Studien einheitlich die Verletzungshistorie als einen starken Risikofaktor für Verletzungen gleicher oder anderer Art. Zusätzlich wurden stärkere Asymmetrien der Extremitäten nach Verletzungen der unteren Extremität festgestellt. Es gibt aktuell wenig bekannte Studien, die sich mit den Auswirkungen von Verletzungen auf die Beinsymmetrie bei Nachwuchsfußballern befasst haben. Außerdem gibt es nach aktuellem Kenntnisstand nur wenige Untersuchungen zu Veränderungen von Asymmetrien bei Nachwuchsfußballern unterschiedlicher Altersklassen. Zielsetzung: Daher war das Ziel dieser Masterarbeit zu untersuchen, inwiefern sich eine vorherige Verletzung in der Rückrunde der letzten Saison bei Nachwuchsfußballern auf die Beinsymmetrie in Kraft- und koordinativen Tests auswirkt. Ein weiteres Ziel dieser Arbeit war es zu prüfen, ob es Unterschiede in der Beinsymmetrie bei Nachwuchsfußballern unterschiedlicher Altersklassen gibt. Methodik: Es handelte sich um eine retrospektive Analyse. Die Verletzungen der Nachwuchsspieler der Tiroler Akademie der Rückrunde der letzten Saison wurden evaluiert. Insgesamt nahmen 59 Spieler der U15, U16 und U18 im Alter von 14-17 Jahren an der Untersuchung teil. Mittels einer Testbatterie aus 6 verschiedenen Kraft- und Koordination Tests wurde die Beinsymmetrie (Limb Symmetrie Index) der Spieler in der Vorbereitung der Saison analysiert. Es wurden folgende Testverfahren angewendet: Y-Balance Test (YBT), Single-Leg Hop (SLH), einbeiniger Stability Test (ST), is, Introduction: Soccer has one of the highest injury rates in all sports. High injury rates of the lower extremity have also been reported in elite youth soccer players. Recently, risk factors for sports injury have been investigated in many studies. Research indicates that greater asymmetry in lower body functional performance displays a modifiable risk factor. In addition, a previous injury has been identified as another strong risk factor for a subsequent lower limb injury. In this context, greater asymmetries have been reported in athletes after injuries. Currently, there is a lack of evidence about the impact of lower limb injuries on leg symmetry in youth soccer players. Moreover, only few studies have evaluated the effect of maturation on leg symmetry in youth athletes. Objective: Therefore, the aim of this study was to investigate the impact of a previous lower limb injury on lower limb symmetry in strength related and coordination related tasks in elite youth soccer players. Another aim was to evaluate the effect of age on leg symmetry in three different age groups. Methods: This study was a retrospective analysis. All injuries of the players of the Tyrolean youth soccer academy in the second half of the last season have been analyzed. 59 players of three age groups (U15, U16, U18) with the age of 14-17 years participated in this study. A screening battery, consisting of 6 different tests (coordination and strength related) was used to determine the leg symmetry (limb symmetry index). The following test were applied: Y- Balance Test (YBT), single-leg hop (SLH), one-leg stability Test (ST), one-leg isometric press strength test (ILT), one-leg isometric knee flexion test (HISO), Nordic Hamstring Exercise (NHE). A linear regression analysis was conducted to examine if a previous injury displays a predictor for leg symmetry. Furthermore, differences in leg symmetry between the age groups were examined. The level of significance was set at p<0.05. Results: 41 inju, eingereicht von BSc, BSc Sven Hansen, in englischer Sprache, Masterarbeit Universität Innsbruck 2021

The purpose of this research was to assess relationships between subjective and external measures of training load in professional youth footballers, whilst accounting for the effect of the stage of the season. Data for ratings of perceived exertion (RPE) and seven global positioning systems (GPS) derived measures were collected from 20 players (age=17.4±1.3yrs, height=178.0±8.1 cm, mass=71.8±7.2 kg) across a 47-week season. The season was categorised by a pre-season phase, and two competitive phases (Comp1, Comp2). The structure of the data were investigated using principal component analysis. An extraction criterion of component with eigenvalues ≥1.0 was used. Two components were retained for the pre-season period explaining a cumulative variance of 77.1%. Single components were retained for both Comp1 and Comp2 explaining 73.3% and 74.3% of variance, respectively. Identification of single components may suggest that measures are related and can be used interchangeably, however these interpretations should be considered with caution. The identification of multiple components in the pre-season phase suggests that univariate measures may not be sufficient when considering load experienced. These results suggest that factoring load based on measures of volume and intensity should be considered.