ABSTRACT
Independent locomotion provides autonomy for infants, drastically changing their relationship with their surroundings. From a dynamic systems perspective, the interaction between environment, tasks, and organismic constraints leads to the emergence of new behaviors over time. This 6-month longitudinal study aimed to verify associations between the emergence of locomotor behaviors and infants' characteristics, developmental status, parental beliefs, and practices. This observational study remotely assessed 37 full-term Brazilian infants aged 5 to 15 months, divided into two groups (G1: 5 to 11 months, n = 19; and G2: 9 to 15 months, n = 18). The motor developmental status of infants was closely associated with the emergence of behaviors (p < 0.05). Infants in G2 whose parents agreed with the statement "In typically developing infants, motor development occurs naturally and there is no need to actively stimulate it" started to walk later than those whose parents disagreed. Infants whose parents expected them to walk around 10-11 months walked earlier compared to those expected to walk after 11 months (G2, p = 0.011). Infants in G2 with a high frequency of staying in the supine position started to walk, both with and without support, later than those with a low frequency (p < 0.05). For infants in G1 with a high frequency of playing on the floor, locomotion (p = 0.041) and crawling on hands-and-knees (p = 0.007) started sooner compared to those with a low frequency. Staying in the cradle more frequently was related to a later emergence of supported walk (p = 0.046) among infants in G2. The emergence of locomotor behaviors is associated with motor developmental status, the surfaces where the infant plays, and body position. Parental beliefs and expectations influence how infants are stimulated and, consequently, the emergence of independent walking.
ABSTRACT
The aim of this study was to define a method for evaluating a player's decisions during a game based on the success probability of his actions and for analyzing the player strategy inferred from game actions. There were developed formal definitions of i) the stochastic process of player decisions in game situations and ii) the inference process of player strategy based on his game decisions. The method was applied to the context of soccer goalkeepers. A model of goalkeeper positioning, with geometric parameters and solutions to optimize his position based on the ball position and trajectory, was developed. The model was tested with a sample of 65 professional goalkeepers (28.8 ± 4.1 years old) playing for their national teams in 2010 and 2014 World Cups. The goalkeeper's decisions were compared to decisions from a large dataset of other goalkeepers, defining the probability of success in each game circumstance. There were assessed i) performance in a defined set of classes of game plays; ii) entropy of goalkeepers' decisions; and iii) the effect of goalkeepers' positioning updates on the outcome (save or goal). Goalkeepers' decisions were similar to the ones with the lowest probability of goal on the dataset. Goalkeepers' entropy varied between 24% and 71% of the maximum possible entropy. Positioning dynamics in the instants that preceded the shot indicated that, in goals and saves, goalkeepers optimized their position before the shot in 21.87% and 83.33% of the situations, respectively. These results validate a method to discriminate successful performance. In conclusion, this method enables a more precise assessment of a player's decision-making ability by consulting a representative dataset of equivalent actions to define the probability of his success. Therefore, it supports the evaluation of the player's decision separately from his technical skill execution, which overcomes the scientific challenge of discriminating the evaluation of a player's decision performance from the action result.
Subject(s)
Decision Making , Soccer , Sports , Adult , Humans , Young AdultABSTRACT
Resumo A proposta do presente estudo consiste em verificar a ocorrência temporal dos gols do Campeonato Brasileiro de 2011. Foram analisados 1.017 gols nas 380 partidas da competição. O tempo de jogo foi dividido em períodos pré-definidos de 15 minutos, além dos acréscimos de cada tempo. Os resultados mostram a maior frequência de gols na segunda etapa e que dentro desse período as maiores ocorrências de gols aconteceram a partir dos 60 minutos de jogo. A análise estatística aponta para diferenças significativas no número de gols marcados entre os períodos 0-15 min. x 60-75 min. (p = 0,001) e entre 0-15 min. x 75-90 min. (p = 0,002). O estudo conclui que no Campeonato Brasileiro de 2011 mais gols foram marcados nos 30 minutos finais da segunda etapa, que há maior ocorrência de gols nos acréscimos do segundo tempo em relação ao primeiro e que a separação dos acréscimos do tempo normal de jogo influenciou a classificação temporal dos gols.
Abstract The purpose of the present study was record the time of goals in Brazilian Championship 2011. We analyzed 1017 goals in 380 matches in the competition. The playing time is divided into predefined periods of 15 min. beyond the additions each time. The results show a higher frequency of goals in the second half and that within this period the highest incidences of goals occurred after 60 min. of play. Statistical analysis indicates significant differences in the number of goals scored in the periods 0-15 min. x 60-75 min. (p = 0.001) and between 0-15 min. x 75-90 min. (p = 0.002). The study concludes that the Brazilian championship 2011 more goals are scored in the final thirty minutes of the second half, there is a greater occurrence of goals in additions time of the second half over the first half, and the separation of normal time of additional time influenced the temporal classification of goals.
Resumen El propósito de este estudio es determinar la incidencia de los goles del Campeonato Brasileño 2011. Se analizaron 1.017 goles en 380 partidos de la competición. El tiempo de juego se divide en períodos predefinidos de 15 minutos, aparte de los añadidos de cada tiempo. Los resultados muestran mayor frecuencia de goles en la segunda parte y que dentro de este período las mayores incidencias de goles se produjeron a los 60 minutos de juego. El análisis estadístico indica diferencias significativas en el número de goles marcados en los períodos 0-15 minutos × 60-75 minutos (p = 0,001) y entre 0-15 minutos × 75-90 minutos (p = 0,002). El estudio concluye que en el Campeonato Brasileño 2011 se anotaron más goles en los últimos treinta minutos de la segunda parte, que hay mayor incidencia de goles en el tiempo añadido de la segunda parte en relación con la primera, y que la separación del tiempo añadido del tiempo reglamentario influyó en la clasificación temporal de los goles.
