Alonso-Callejo, A, García-Unanue, J, Guitart-Trench, M, Majano, C, Gallardo, L, and Felipe, J. Validity and reliability of the acceleration-speed profile for assessing running kinematics' variables derived from the force-velocity profile in professional soccer players. J Strength Cond Res 38(3): 563–570, 2024—The aim of this research is to assess the validity and reliability of the acceleration-speed profile (ASP) for measuring the mechanical variables of running kinematics when compared with the force-velocity profile (FVP) obtained by reference systems. The ASP and FVP of 14 male players of an elite football club were assessed during a competitive microcycle. Three ASPs were tested according to the number and type of sessions included in its plotting (ASP1: 5 training sessions and competitive match; ASP2: 5 training sessions; ASP3: competitive match). Force-velocity profile was tested 4 days before match (MD-4) with a 30-m linear sprint using 3 previously validated devices (encoder, mobile App, and global positioning system). Level of significance was p < 0.05. Acceptable reliability (intraclass correlation coefficient > 0.5) was found between the ASP1 and the encoder for all variables (F₀-A₀, V₀-S₀, and V_max). The more reliable ASP method was the ASP1 showing a lower bias than the ASP2 and ASP3 methods for almost all variables and reference systems. For ASP1, lower mean absolute error (MAE: 0.3–0.5) and higher correlation (P-M corr: 0.57–0.92) were found on variables related to the velocity in comparison with variables related to the early acceleration phase (F₀-A₀; MAE: 0.49–0.63; P-M corr: 0.13–0.41). Acceleration-speed profile, when computed with data from a complete competitive week, is a reliable method for analyzing variables derived from velocity and acceleration kinematics. From these results, practitioners could implement ASP and the applications of the FVP previously studied, such as resistance training prescription, performance assessment, and return-to-play management.

Football is a very demanding sport which requires players to exert maximum effort, producing fatigue and eventually injuries. Thermography can be used to detect fatigue and prevent its consequences through thermal asymmetries in the bilateral body areas; however, its adequacy for elite footballers has not been widely studied. Therefore, the objective of the present investigation was to determine the suitability of thermography to detect fatigue in male football players. For this reason, twenty participants were gathered into a pair of subgroups (low [ 0.05) were found in any of the RSA test variables between low and high thermal asymmetry groups for thighs and calves. On the other hand, the low thermal asymmetry hamstring group reported a smaller percentage difference in sprints for the first sprint (%Diff) and a larger percentage difference in sprints two and three with respect to the best sprint (%Best). For CMJs, the low thermal asymmetry hamstring group reported significantly higher values post-RSA test, indicating better performance. Accordingly, thermography can provide information about performance in CMJ and RSA tests through hamstring asymmetries over 0.2 °C. Meanwhile, larger asymmetries than 0.2 °C in calves and thighs do not seem to be related to performance in these tests; therefore, coaches should consider if it is optimal to align players with high hamstring asymmetries.

The choice of service delivery form (direct management, agencification, or indirect management) is one of the most important decisions in the strategic planning of sports systems. However, its influence on efficiency has not been adequately studied in the scientific literature. The aim of this paper is to analyse the service delivery form of sports services on cost efficiency and to study the implications the use of different inputs has for the analysis of cost efficiency in sports services. To answer the objectives of the study, the analysis is divided into three stages. First, the cost efficiency of municipal sports services is estimated through the partial order-m robust frontiers using two different measures of cost (budgetary expenditures and effective cost). Then, the two cost-efficiency estimations were compared by the Li test to analyse the existence of significant differences. Finally, cost efficiency was regressed on several environmental factors by a bootstrapped truncated regression. The results show that there is no significant relationship between the different forms of management when the effective cost is included as an input. However, there is a significant relationship when the budgetary expenditure is specified as input; in this case, direct municipal management is the delivery form with the highest efficiency.

The aim of this study was to analyse the physical demands of U10 players in a 7-a-side-soccer tournament based on the playing positions in 6 consecutive matches by global positioning systems (GPS). Variables of total distance, relative distance in different speed zones, maximum speed, time interval between accelerations, maximum speed acceleration, maximum acceleration, acceleration distance and the number of high-intensity accelerations were analysed. Differences between playing positions were found in the total distance covered by the midfielders. They covered higher total distances than the defenders (+1167 m; 95% CI: 411 to 1922 m; effect size (ES) = 1.41; p < 0.05) and forwards (+1388 m; CI 95%: 712 a 2063 m; TE = 0.85; p < 0.05). The total covered distance increased in the final rounds with respect to the group stage (p < 0.05; ES: 0.44 to 1.62), and high-intensity actions, such as the number of accelerations, were greater in the final rounds compared to the group stage (p < 0.05; ES: 0.44 to 1.62). The physical performance of young football players in a tournament with consecutive matches on a 40 × 62 m football field on the same day is influenced by the playing position and dependent on the level difference between opponents.

The aim of this study was to analyse the effects of the type of extracurricular sport on the body composition, respiratory parameters, and physical condition in prepubertal and pubertal girls. Four hundred and eighty-five female athletes (aged 8–14) from different sports participated in this study. They were gathered into four groups according to the sport typology and maturity level: ‘prepubertal girls who practise collective sports’ (PRE-CS), ‘prepubertal girls who practise individual sports’ (PRE-IS), ‘pubertal girls who practise collective sports’ (PUB-CS), and ‘pubertal girls who practise individual sports’ (PUB-IS). The cardiorespiratory fitness (the 20 m shuttle run test, 20 mSRT), anthropometry, respiratory capacity (forced spirometry), handgrip, CMJ test, and stabilometry were collected. Prepubertal girls showed a lower muscle mass (kg) and fat mass (kg) than pubertal girls regardless of the extracurricular sports typology. PRE-CS and PRE-IS also showed a lower respiratory fitness and physical fitness than pubertal girls (p < 0.05). Pubertal girls did not show significant differences (p > 0.05) in any of the body composition, respiratory fitness, and physical fitness variables when comparing between collective sports and individual sports. The results show that extracurricular participation in these types sports by prepubertal girls can influence their body composition, respiratory fitness, and physical condition.