RESUMEN

The authors wish to make the following corrections to this paper [...].

RESUMEN

The aim of this study was to examine the effects of chronological age on acceleration and deceleration match performance in professional soccer players. A total of 5317 individual match observations were collected on 420 professional players competing in the Spanish LaLiga during the 2018-2019 season, using a multiple-camera computerised tracking system (TRACAB; ChyronHego, Melville, NY, USA). Players were classified using a k-means cluster analysis into four different age groups: 17-23 years, 24-27 years, 28-30 years, and 31-38 years. Linear mixed models were adjusted to compare the players' match performance according to their age group and playing position (central defenders, external defenders, central midfielders, external midfielders, and forwards). The results showed that players aged between 31-38 years performed a significantly less total number of accelerations (ES=0.30-0.48) and decelerations (ES=0.29-0.49) in comparison with younger players. These age-related physical performance declines were more pronounced among central defenders, central midfielders, and forwards. However, no significant effects were obtained for players' maximum acceleration and deceleration capacities. The current findings provide useful information for coaches and strength and conditioning specialists to better understand the effects of age on players' physical performance and to develop age-tailored training programs.

Asunto(s)

RESUMEN

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) forced a stoppage in the 2019/2020 season of LaLiga™, possibly influencing performance indicators in the return to competition. Therefore, here, we evaluated whether the stoppage due to the coronavirus 2019 disease (COVID-19) lockdown influenced physical performance compared to the start of LaLigaTM in terms of high-intensity efforts. Using a semi-automatic, multiple-camera system, running activities during 22 matches were analyzed. We compared the first 11 matches of the season (pre-lockdown) with the 11 matches just after the restart of LaLiga™ (post-lockdown). The results showed higher (p < 0.05) performance in the pre-lockdown period compared with the post-lockdown period, including in medium-speed running (14.1-21 km/h), high-speed running (21.1-24 km/h), and sprinting speed running distances (>24 km/h). However, the number of accelerations/min and decelerations/min were significantly higher during the post-lockdown period. Therefore, we conclude that the stoppage due to the COVID-19 lockdown generated lower physical performance in the post-lockdown period compared with the pre-lockdown period, most likely due to the accumulation of matches (congested schedules).

Asunto(s)

RESUMEN

BACKGROUND: The aims of this study were: 1) to investigate the impacts that an eccentric overload training (EOT) and a small-side game training (SSGT) have on the characteristics of the accelerations (ACC) and decelerations (DCC) of the players in a soccer match; and 2) to determine if EOT and SSGT could affect the ACC and DCC reduction over time in a soccer match. METHODS: Twenty-three female soccer players from a Spanish professional club were split into three groups: a small-sided game training group (SGG), an eccentric overload training group (EOG) and a control group (CG). RESULTS: The SSG improved the high intensity distance performed (ES [CI]=0.72 [0.22; 1.22]), the number of high intensity actions (ES [CI]=0.65 [0.01; 1.29]), the percentage of repeated high intensity actions (ES [CI]=0.54 [-0.17; 1.25]), the initial velocity of the ACC (ES [CI]=0.55 [-0.08; 1.17]) and the percentage of repeated accelerations (ES [CI]=0.87 [-0.18; 1.91]) with respect to the control group. The EOG obtained better results in distance travelling accelerating (ES [CI]=0.84 [0.09; 1.60]) and decelerating (ES [CI]=0.87 [0.23; 1.51]) above 3 m/s2, maximum ACC (ES [CI]=1.92 [0.90; 2.94]) and DCC (ES [CI]=1.29 [0.44; 2.14]) and the average of maximum ACC (ES [CI]=0.89 [0.23; 1.54]) and DCC (ES [CI]=1.08 [0.62; 1.55]) with respect to the CG. A decrement in the ACC and DCC performance was observed between the first and last 15 minutes of the competition, except for the EOG. CONCLUSIONS: The SSG obtained mainly improvements in variables related with efforts repetitions and the capacity of maintaining the ACC and the DCC over time, while improvements in the EOG were related to intensity in the ACC and DCC.

Asunto(s)

RESUMEN

ABSTRACT: Rey, E, Kalén, A, Lorenzo-Martínez, M, López-Del Campo, R, Nevado-Garrosa, F, and Lago-Peñas, C. Elite soccer players do not cover less distance in the second half of the matches when game interruptions are considered. J Strength Cond Res XX(X): 000-000, 2020-This study aimed to analyze quantitative differences in the physical demands of male elite soccer players between the first and second halves during official matches, accounting for effective playing time (the duration of play after subtracting the game interruptions) and playing positions. A total of 4,249 individual match observations of 412 outfield players competing in the Spanish first division league (LaLiga) were undertaken during the 2018-2019 season, using a computerized tracking system (TRACAB, Chyronhego, New York, NY). The players were classified into 5 positional roles: central defenders (CD), external defenders (ED), central midfielders (CM), external midfielders (EM), and forwards (F). The main results showed that in contrast to those observed when total playing time was considered, independent of playing position, there were no significant differences on high-speed running (HSR) (5.5 ± 2.4 vs. 5.5 ± 2.4 m·min-1) and sprint (5.3 ± 3.3 vs. 5.4 ± 3.3 m·min-1) distances between the first and second halves in professional soccer players when the effective playing time was considered. However, differences in match running performance at HSR and sprint distances between the first and second halves were dependent on players' playing position. Whereas ED and EM maintained HSR and sprint efforts during the second half, CD and CM significantly increased (p < 0.001) the distance covered at sprint during the second period of the match. Contrarily, F were unable to maintain their HSR (6.2 ± 2.3 vs. 5.9 ± 3.3 m·min-1) and sprint (7.0 ± 3.5 vs. 6.5 ± 3.4 m·min-1) match running performances during the second half. Such findings demonstrate that total playing time could overestimate fatigue-induced performance declines. Thus, effective playing time and playing position should be taken into account when interpreting the match running performance of professional soccer players.

RESUMEN

The aim of this study was to investigate the effects of fatigue induced by repeated sprint in the kicking accuracy and velocity in female soccer players. Eighteen Under-23 female soccer players from a Spanish professional club were subjected to a fatigue protocol based on a repeated-sprint ability (RSA) test. Measurements of the kicking velocity (maximal ball velocity) and accuracy (Loughborough Soccer Shooting Test) were taken before and after fatigue induction. Correlations between the change in the maximal ball velocity/accuracy and the heart rate (HR), the fatigue index (FI), the sprint decrement (Sdec) and the rating of perceived exertion (RPE) were made. There was a significant difference between maximal ball velocity under fatigue conditions with respect to non-fatigue conditions (p = 0.001; ES = 0.89). However, despite a lower kicking accuracy punctuation with fatigue, this was not statistically significant (p = 0.433; ES = 0.22). Significant correlations were found between the maximal kicking velocity and the FI (r = 0.632, p < 0.01) and the Sdec (r = -0.554, p < 0.05) and between the kicking accuracy and the RPE (r = -0.506, p < 0.05). In conclusion, there was a significant reduction in the maximal kicking velocity, but not in the kicking accuracy, under fatigued conditions. The RSA-related FI and Sdec were the best predictors of the maximal kicking velocity and the RPE for the kicking accuracy.

Asunto(s)

RESUMEN

El objetivo del estudio fue comparar las demandas físicas de dos situaciones de fútbol reducido, modificando el espacio relativo de juego. El estudio siguió un diseño pre-experimental de grupo único. Un total de diez deportistas profesionales pertenecientes a un equipo de primera división de la liga española de futbol fueron sometidos a dos tareas de fútbol reducido: 7x7 (25x45 m) y 11x11 (60x45 m). Mediante GPS se midieron las siguientes variables cinemáticas: distancia recorrida, distancia recorrida a alta intensidad, número de aceleraciones moderadas, número de aceleraciones medias, número de aceleraciones máximas, duración de las aceleraciones, y distancia recorrida durante las aceleraciones. Se procedió con estadística descriptiva y, tras comprobar la normalidad de las distribuciones, se procedió con prueba T para muestras relacionadas, estimándose el tamaño del efecto mediante el porcentaje de cambio. En la situación 11x11 los jugadores recorrieron más distancia (p = 0,003), corrieron más distancia a altas velocidades (p = 0,016) y se produjeron aceleraciones más duraderas en tiempo (p = 0,017) y en distancia recorrida (p = 0,001). En la situación de juego 7x7 se registraron mayor número de aceleraciones moderadas (p = 0,002) y medias (p = 0,004). Mientras que la carga de trabajo total es mayor en la situación 11x11, el 7x7 es más exigente en cuanto a aceleraciones y cambios de ritmo, lo que implica una carga interna distinta, de orientación más neuromuscular. A juicio de los autores de este trabajo, las demandas físicas propias del 7x7, en el que se realizan un mayor número de aceleraciones, convierten al 7x7 en un ejercicio idóneo para trabajar la fuerza específi ca en un contexto en el que se integran aspectos físico, técnico y táctico

The aim of the present study was to compare the physical demands of two SSG (small sided games) modifying the relative pitch area per player. The study followed a pre-experimental design only group. A total of ten professional soccer players belonging to a team of Spanish fi rst division soccer league were monitored during two diff erent SSG: 7x7 (25x45 m) and 11x11 (60x45 m). Using GPS the following cinematic variables were measured: distance, distance at high speed running, number of moderate accelerations, average number of accelerations, number of maximal acceleration, duration of acceleration, and distance traveled during acceleration. After checking the normal distribution, data were analyzed by T test for related sample, and eff ect size was estimated using percentage change. According to the results, in 11x11 SSG players covered more total distance (p = 0.003), covered more distance at high intensity running (p = 0.016) and accelerations occurred along more time (p = 0.017) and distance (p = 0.001). In the 7x7 SSG more number of moderate (p = 0.002) and medium (p = 0.004) accelerations were registered. Even though the total workload is higher in the 11x11 situation, 7x7 is more demanding in terms of accelerations and direction changes, which implies a diff erent internal load, more neuromuscular. Furthermore, the physical demands of the SSG 7x7, where a higher number of accelerations are performed, becoming the 7x7 an ideal task to work specifi c strength, in a context where physical, technical and tactical aspects are integrated

Asunto(s)