Application of arbitrary and individualized load quantification strategies over the weekly microcycle in professional soccer players.

The aims of this study were to: (a) determine the differences in external load quantification between arbitrary and individual speed thresholds over the weekly microcycle in professional soccer players, and (b) analyse the association between internal load and different external load quantification strategies (ELQSs). Ten professional outfield players were monitored during training sessions and official matches using 10 Hz GPS devices over a 6-week in-season period. The absolute and relative ("R" before the distance category) distances covered were calculated for the following external load variables: medium-intensity running distance (MIR), high-intensity running (HIR), sprint distance (SD), and very high-intensity running (VHIR). Individualized thresholds were determined based on maximal sprinting speed (MSS) and the last speed achieved during the 30-15 Intermittent Fitness Test (VIFT) of each player. In terms of match-day workload, significant differences (p < 0.05) were observed between arbitrary and individualized strategies (i.e., MSS and VIFT) for the distance covered in MIR, HIR, SD, VHIR, RHIR, RSD, and RVHIR. The MSS strategy compared to arbitrary thresholds revealed significant differences (p < 0.05) for distance covered in HIR, RHIR, and VHIR during all training sessions. The present results showed that arbitrary thresholds lead to underestimation of external load absolute and relative metrics compared to the MSS strategy throughout the microcycle. The VIFT strategy mainly revealed differences in external load quantification regarding MD compared to arbitrary thresholds. Individualized speed threshold strategies did not achieve better associations with internal load measures in comparison with arbitrary thresholds in professional soccer players.

Influence of the Weekly and Match-play Load on Muscle Injury in Professional Football Players.

The aim of this investigation was to examine the impact of the weekly training load and the match running patterns prior to a muscle injury as potential risk factors of muscle injury in professional football players. Forty male professional football players participated in the investigation. Running distances at different intensities 5 min and 15 min prior to the injury were compared to the same time-points in official matches of the same player with no injury events. Furthermore, the cummulative session rating of perceived exertion (sRPE) and training load of the week prior to the injury were compared to a control week (mean value of training weeks without injury). Nineteen players suffered 31 non-contact muscle injuries during matches. The distance covered at 21-24 km/h (p<0.001; effect size (ES)=0.62) and at>24 km/h (p=0.004; ES=0.51) over the 5-min period prior to the injury was greater than in matches without injury. The cumulative sRPE (p=0.014; ES=1.33) and training volume (p=0.002; ES=2.45) in the week prior to the injury was higher than in a control week. The current data suggest that the combination of a training week with a high load and a short period of high intensity running during the match might increase the risk of muscle injury in professional footballers.

Analysis of professional soccer players in competitive match play based on submaximum intensity periods.

The main objective of this study is to analyse sub-maximum intensity periods (SubMIP's) manifested by professional soccer players during official matches (number of events and time spent in each event), according to the player position, match halve and match, and also to group the players according to their SubMip values during the competition. Methods: We collected a total of 247 individual records of 14 players using Global Positioning System (GPS) during 15 official league matches (Azerbaijan Premier League 2019-2020). We calculated both the number of SubMIPs events and the time each player spent in the SubMIPs zone (threshold of 85% MIP). We analysed the possible independence of the variables with the Kruskal-Wallis test and the possible specific relationships between the groups using a post-hoc analysis with Dunn's test. In order to explore the possible distribution of physical demands in homogeneous groups, a cluster analysis was performed. Results: The statistical analysis showed significant differences between the individual variables in the number of events and in the time spent by the player above the threshold in distance covered at speed >19.8 km/h (HSR), distance covered at speed >25.2 km/h (Sprint), acceleration density (AccDens), mean metabolic power (MetPow), metres per minute (Mmin) and high metabolic load distance >25.5 W/kg (HMLD). Differences were also found according to the playing position in MetPow, Mmin and between halves in AccDens, MetPow, Mmin. In the clustering based on the time spent by the player in SubMIPs, three main groups were described: (1) the centroid was located in lower values in each of the variables; (2) there were an accentuation of the AccDens variable; (3) all the variables, except AccDens, were accentuated. Conclusions: The main differences with regard to SubMIPs were related to the player's individual physical performance and not to position. However, the player's position could act as an attractor and show significant differences during matches.

Relationships between rating-of-perceived-exertion- and heart-rate-derived internal training load in professional soccer players: a comparison of on-field integrated training sessions.

PURPOSE: To describe the internal training load (ITL) of common training sessions performed during a typical week and to determine the relationships between different indicators of ITL commonly employed in professional football (soccer). METHODS: Session-rating-of-perceived-exertion TL (sRPE-TL) and heart-rate- (HR) derived measurements of ITL as Edwards TL and Stagno training impulses (TRIMPMOD) were used in 9 players during 3 periods of the season. The relationships between them were analyzed in different training sessions during a typical week: skill drills/circuit training + small-sided games (SCT+SSGs), ball-possession games+technical-tactical exercises (BPG+TTE), tactical training (TT), and prematch activation (PMa). RESULTS: HR values obtained during SCT+SSGs and BPG+TTE were substantially greater than those in the other 2 sessions, all the ITL markers and session duration were substantially greater in SCT+SSGs than in any other session, and all ITL measures in BPG+TTE were substantially greater than in TT and PMa sessions. Large relationships were found between HR>80% HRmax and HR>90% HRmax vs sRPE-TL during BPG+TTE and TT sessions (r=.61-.68). Very large relationships were found between Edwards TL and sRPE-TL and between TRIMPMOD and sRPE-TL in sessions with BPG+TTE and TT (r=.73-.87). Correlations between the different HR-based methods were always extremely large (r=.92-.98), and unclear correlations were observed for other relationships between variables. CONCLUSION: sRPE-TL provided variable-magnitude within-individual correlations with HR-derived measures of training intensity and load during different types of training sessions typically performed during a week in professional soccer. Caution should be applied when using RPE- or HR-derived measures of exercise intensity/load in soccer training interchangeably.

Interchangeability of two tracking systems to register physical demands in football: multiple camera video versus GPS technology / Intercambiabilidad de dos sistemas de seguimiento para registrar lasdemandas físicas en el fútbol: video cámara múltiple versus tecnología GPS

The main aim of this investigation was to study the agreement between the distances covered at various speeds by professional soccer players in official matches using a Video-based system (VBS) and a Global Position System (GPS), and to create equations that predict distances from those obtained by other technologies. For these purposes twelve professional soccer (La Liga Santander) players' activities in official matches were registered simultaneously with a semi-automatic multiple-camera or VBS (TRACAB(R), system offered by Mediacoach(R)) and GPS (GPEXE(R), Exelio, Udine, Italia). The measured variables were the distance covered by the players at various speeds ranges such as: < 7, from 7 to 14, from 14 to 21, from 21 to 24, and > 24, (all in km.h-1) and as well several time slots (15, 30 and 45 minutes) were considered. The agreement between the distance recorded by VBS and GPS was studied using the Bland-Altman method. Furthermore, calibration equations using linear regression models were calculated in order to allow interchangeability of data from VBS to GPS and viceversa. The results showed that the agreement between VBS and GPS was low due to elevated systematic (from 3.3 m to -164.4 m) and random error (from 29.3 m to 274.8 m). VBS measured systematically more distance that GPS and the difference between VBS and GPS tended significantly to rise as the distance increased. However, the calibration equations were significant (p < 0.05) and predicted the distance from one system to another well (R2 = 0.55-0.90). In conclusion, the distance recorded by VBS and GPS cannot be used interchangeably and the calibration equations provided by this study should be used to compare or exchange distances between the two systems

Los objetivos de este estudio han sido estudiar el grado de acuerdo entre las distancias recorridas a diferentes velocidades por jugadores profesionales del futbol (La Liga Santander) registradas por el sistema semiautomático de multi-cámara (VBS) y el Sistema de Posicionamiento Global (GPS), y encontrar ecuaciones de calibración entre los dos sistemas. Para ello se regis-traron las actividades de once jugadores profesionales de fútbol en partidos oficiales simultáneamente con el VBS (TRACAB(R), system offered by Mediacoach(R)) y GPS (GPEXE(R), Exelio, Udine, Italia). Las variables medidas fueron la distancia recorrida por los jugadores en diferentes rangos de velocidad, tales como: < 7, de 7 a 14, de 14 a 21, de 21 a 24, y > 24, (todos en km.h-1) considerándose varios intervalos de tiempo (15, 30 y 45 minutos). El acuerdo entre la distancia registrada por VBS y GPS se estudió utilizando el método de Bland-Altman. Además, las ecuaciones de calibración, usando modelos de regresión lineal, se calcularon para permitir la intercambiabilidad de datos del sistema semiautomático a los GPS y viceversa. Los resultados mostraron que el acuerdo entre VBS y GPS fue bajo debido a un elevado error sistemático (de 3.3 m a -164.4 m) y aleatorio (de 29.3 m a 274.8 m). VBS midió sistemáticamente más distancia que GPS y la diferencia entre VBS y GPS tendió a aumentar significativamente a medida que aumentó la distancia recorrida. Sin embargo, las ecuaciones de calibración fueron significativas (p < 0.05) y predijeron bien la distancia de un sistema a otro (R2= 0.55-0.90). En conclusión, la distancia registrada por VBS y GPS no se puede utilizar de manera intercambiable y las ecuaciones de calibración proporcionadas por este estudio se podrían usar para comparar e intercambiar las distancias entre los dos sistemas

Propuesta de readaptación tras meniscectomía parcial en futbolistas / Proposed rehabilitation after partial meniscectomy in soccer players

Las lesiones de menisco son habituales en el fútbol, aunque su frecuencia es más baja que las lesiones musculotendinosas u otras lesiones de rodilla en este deporte. Cuando estas lesiones necesitan intervención quirúrgica, actualmente se opta por conservar la mayor parte del menisco posible, evitando o retrasando de esta forma la posible artrosis futura. Por tanto, la meniscectomía parcial se ha convertido en la intervención más exitosa para el tratamiento y la curación de las lesiones meniscales. Una temprana e intensiva rehabilitación tras la misma puede llevar a reducir el tiempo de baja, permitiendo al futbolista regresar a la competición de forma más segura. Así, el proceso de readaptación deportiva ha de ser correctamente planificado, tanto para la zona lesionada como para el resto de estructuras que inciden en el rendimiento deportivo del futbolista, teniendo como meta final una segura integración a los entrenamientos y a la competición(AU)

Meniscus injuries are quite common in soccer, although they are less frequent than muscle or tendon injuries or other knee injuries in this sport. Nowadays, when surgery is needed for these injuries, the majority of the meniscus is conserved, avoiding or delaying any future possible degenerative osteoarthritis. Therefore, partial meniscectomy has become one of the most successful surgeries for treating and healing meniscus injuries. An early and intensive rehabilitation can lead to a reduction in time off training, enabling the soccer player to safely return to competition. Thus, the rehabilitation process must be properly planned, both for the injured area and the other structures that affect the sports performance soccer player, with the final aim being to restart training sessions and competition(AU)