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We present a critical reflection on the mechanical variable Player Load, which is based on acceleration data and commonly used in sports. Our motivation to write this paper came from the difficulties that we encountered in the calculation and interpretation of Player Load using our own data, since we did not use the Catapult Sports equipment, which is a merchandise of the company that proposed this variable. We reviewed existing literature in order to understand Player Load better; we found many inconsistencies in PL calculation methods and in the meanings attached to it. Accordingly, this paper presents a brief discussion on the meanings that have been assigned to Player Load, its limitations, and the lack of clear and complete information about Player Load calculation methods. Moreover, the use of arbitrary units and different practical meanings in the literature has associated Player Load with many physical quantities, thereby resulting in difficulties in determining what Player Load measures within the context of sports. It seems that Player Load is related to the magnitude of changes in acceleration, but not the magnitude of acceleration itself. Therefore, coaches and sports scientists should take this information into account when they use Player Load to prescribe and monitor external loads. We concluded that a deeper discussion of Player Load as a descriptor of external load is warranted in the sports sciences literature.

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ABSTRACT This study aimed compare individual tactical behavior and network properties of players with higher and lower tactical skills during soccer small-sided games. The sample was composed of 18 U-17 elite soccer players (16.2 years old) from the same national level team. Players were divided into group 1 and group 2, with higher and lower tactical skill, respectively, measured by the FUT-SAT. After this, they played 12 small-sided games in a 36x27m field with all rules of the formal game. Players' tactical behavior was assessed through the incidence of fundamental tactical principles during the SSG. Total links, density and clustering coefficient were defined as the general network metrics. Data were analyzed through independent t-test and Mann-Whitney test. Results showed that group 1 presented higher values of total links (p=0.007) and density (p=0.007). Group 1 also presented a higher incidence of defensive unity (p=0.001), while group 2 realized more actions of defensive balance (p=0.008) and recovery balance (p=0.038). We conclude that tactical skills are able to constraint individual team behavior in small-sided games.

RESUMO Este estudo objetivou comparar o comportamento tático individual e as propriedades da rede de interações de atletas com maior e menor capacidade tática durante pequenos jogos no futebol. A amostra foi composta por 19 jogadores de futebol sub-17 (16.2 anos) de um mesmo time, de nível nacional. Jogadores foram divididos em grupo 1 e grupo 2, com maior e menor capacidade tática, respectivamente, medida pelo FUT-SAT. Na sequência, eles participaram de 12 pequenos jogos em um campo de 36mx27m com todas as regras do jogo formal. Avaliou-se o comportamento tático dos jogadores por meio da incidência dos princípios táticos fundamentais durante os pequenos jogos. Total links, densidade e clustering coefficient foram definidos com as medidas das propriedades gerais da rede. Analisaram-se os dados por meio do teste t independente e do teste de Mann-Whitney. Os resultados mostraram que o grupo 1 apresentou maiores valores para total links (p=0.007) e densidade (p=0.007). O grupo 1 apresentou ainda maior incidência de ações de unidade defensiva (p=0.001), enquanto o grupo 2 realizou mais ações de equilíbrio defensivo (p=0.008) e equilíbrio de recuperação (p=0.038). Conclui-se que a capacidade tática influencia o comportamento individual e coletivo durante pequenos jogos.

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Abstract This study aimed to compare the tactical behavior of young soccer players during small-sided games played with team composition criteria based on procedural tactical knowledge, aerobic power and speed performance. Eighteen male soccer players played 3vs.3 small-sided games with teams balanced according to players' performance on Sprint Test, Yo-Yo Intermittent Recovery Test and the field test of the System of Tactical Assessment in Soccer. Data related to the incidence of tactical principles were analyzed through the proportions chi-square test with Bonferroni's correction. One-way ANOVA was used to compare players' offensive and defensive tactical performance. Results showed different incidence of offensive and defensive tactical principles in games with different teams' composition criteria. It has also been shown a higher defensive performance when the teams' composition criteria was based on players' procedural tactical knowledge.

Resumo Este estudo objetivou comparar o comportamento tático de jovens atletas de futebol durante pequenos jogos com critérios de composição das equipes baseados no conhecimento tático processual, capacidade aeróbica e desempenho de velocidade. Dezoito jogadores participaram de pequenos jogos na configuração 3vs.3 com equipes equilibradas de acordo com o desempenho no Teste de Sprint, no Yo-Yo Intermittent Recovery Test e no teste de campo do Sistema de Avaliação Tática no Futebol - FUT-SAT Analisaram-se os dados relativos à incidência dos princípios táticos por meio do teste de qui-quadrado de proporções e conduziram-se comparações pareadas a partir da correção de Bonferroni. Para a comparação do desempenho tático ofensivo e defensivo recorreu-se à ANOVA one-way. Resultados apontaram diferenças na incidência de princípios táticos ofensivos e defensivos a partir da utilização dos três diferentes critérios de composição das equipes. Observou-se ainda maior desempenho tático defensivo a partir da composição das equipes baseada no conhecimento tático processual dos atletas

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OBJECTIVE: The aim of this study was to investigate the behavior of the force applied during the Maitland grade III anteroposterior joint mobilization of the talus and its effect on dorsiflexion range of motion (ROM). METHODS: Two examiners performed measurements of dorsiflexion ROM on both ankles of healthy volunteers using a universal goniometer. The anteroposterior talus mobilization was first applied by examiner A for 30 seconds. Examiner B then repeated the same procedure. A platform was placed under the volunteer's leg to register the forces obtained during mobilization. After the procedure, examiner A assessed the ankle dorsiflexion. RESULTS: The results showed consistency regarding maximal forces applied throughout the 30 seconds of mobilization as well as low consistency upon the minimal forces. A significant increase in dorsiflexion ROM of the ankle was found immediately after joint mobilization. CONCLUSIONS: The results of the present study have shown consistent maximal forces applied by one examiner and inconsistent minimal forces during an ankle mobilization in healthy volunteers when the same examiner was compared. Moreover, the applied force was able to increase dorsiflexion ROM after the Maitland grade III anteroposterior mobilization of the talus.

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