David Rodríguez Ruiz

BASKETBALL SCORING IN NBA GAMES: AN EXAMPLE OF COMPLEXITY

Scoring in a basketball game is a process highly dynamic and non-linear type. The level of NBA teams improve each season. They incorporate to their rosters the best players in the world. These and other mechanisms, make the scoring in the NBA basketball games be something exciting, where, on rare occasions, we really know what will be the result at the end of the game. We analyzed all the games of the 2005-06, 2006-07, 2007-08, 2008-09, 2009-10 NBA regular seasons (6150 games). We have studied the evolution of the scoring and the time intervals between points. These do not behave uniformly, but present more predictable areas. In turn, we have analyzed the scoring in the games regarding the differences in points. Exists different areas of behavior related with the scorea and each zone has a different nature. There are point that we can consider as tipping points. The presence of these critical points suggests that there are phase transitions where the dynamic scoring of the games varies significantly.Abstract Scoring in a basketball game is a highly dynamic, non-linear process. NBA teams try to be more and more competitive each season. For instance, they incorporate into their rosters the best players in the world. This and other mechanisms concur to make the scoring process in NBA games exciting and rarely predictable. This paper is to study the behavior of timing and scoring in basketball games. The authors analyze all the games in five NBA regular seasons (2005–06, 2006–07, 2007–08, 2008–09, 2009–10), for a total of 6150 games. Scoring does not behave uniformly; therefore, the authors also analyze the distributions of the differences in points in the basketball games. To further analyze the behavior of the tail of the distribution, the authors also carry out a semilog-plot and a log-log plot to verify whether this trend approaches a Poisson distribution or a PL. This paper reveals different areas of behavior related to the score, with specific instances of time that could be considered tipping points of the game. The presence of these critical points suggests that there are phase transitions where the dynamic scoring of the games varies significantly.

Gender differences in the knee musculature function in professional volleyball players

Chronic patellar tendinopathy is a common pathology in sporting population. To date, there is no agreed upon protocol as election treatment. Eccentric exercises have been used with satisfactory outcomes (3). The purpose of this trial was to compare the effects of two eccentric exercise protocols.

Normalized response speed and jumping-related techniques after training in female volleyball players

Chronic patellar tendinopathy is a common pathology in sporting population. To date, there is no agreed upon protocol as election treatment. Eccentric exercises have been used with satisfactory outcomes (3). The purpose of this trial was to compare the effects of two eccentric exercise protocols.

Características Antropométricas de los Jugadores Españoles de Voley Playa: Comparación por Categorías

El objetivo de este estudio fue determinar las caracteristicas antropometricas del jugador espanol (hombres y mujeres) de voley playa y comparar el perfil antropometrico de estos deportistas en las diferentes categorias en las que se organiza la competicion: Sub-19, Sub-21 y Absoluto. Fueron evaluados 150 jugadores (79 hombres y 71 mujeres) participantes en el Campeonato de Espana de voley playa celebrado en 2011. La estatura presento valores que responden, en los hombres, a patrones evolutivos propios de edad y morfotipo (Sub19M: 184,50±6,95 cm; Sub21M: 182,89±7,28 cm; AbsM: 186,93±6,58 cm). Este comportamiento no se repitio entre las mujeres (Sub19F: 169,84±6,46 cm; Sub21F: 173,43±5,98 cm; AbsF: 175,28±6,17 cm). El peso muscular aumento por cada categoria con diferencias estadisticamente significativas entre AbsM vs. Sub19M (p=0,002), AbsM vs. Sub21M (p=0,001) y Sub21F vs. Sub19F (p=0,02). Los valores de peso corporal y porcentaje graso mostraron diferencias menos relevantes con diferencias estadisticamente significativas entre el grupo Sub21F (p=0,003) y el Sub19F (p=0,009). Los jugadores espanoles de voley playa Absolutos, tanto hombres como mujeres, presentan un peso corporal y una estatura inferior a la de los jugadores de alto nivel internacional. El peso muscular y el peso graso muestran en ambos sexos, en valores absolutos, valores crecientes con cada categoria de edad, pero no se confirma esta tendencia cuando el parametro se expresa en porcentajes respecto al peso corporal. El jugador de voley playa tiende a incrementar el valor de la mesomorfia con el cambio de categoria, tanto en hombres (3,33±1,09; 3,77±1,28; 4,28±1,07) como en mujeres (2,75±1,02; 2,86±1,21; 3,36±0,92).

THE EFFECT OF EARLY SYSTEMATIC GYMNASTICS TRAINING ON POSTURAL CONTROL

Background Its well established that by the age of 13, children are capable of applying a postural strategy looking very similar to that adopted by the adults. Its also widely acknowledgment that several years of sport training and competition implies to master stability, particularly in those sports requiring fine postural control, such as rhythmic gymnastics (Viullerme, et al, 2001). The aim of this study was to analyze the effect of early systematic gymnastic training on postural performance and control, by comparing young rhythmic gymnastics with their normally active counterparts (non-athletes). Methods Twenty-two gymnastics girls of national level (RG: 9.59±1.1 years old; 29.9±5.5kg; 1.37±0.08 m) and nineteen non-athletes girls (non-AT: 9.74±1.0 years old; 38.7±7.3kg; 1.40±0.07 m) participated in the investigation. All Subjects performed a battery of static balance tests under three different conditions: bipedal posture as immobile as possible for 20 seconds with Eyes Open (EO), Eyes Closed (EC) and Unipedal “en-dehors” Posture (UEP). All test were performed while standing on a platform force (MuscleLab® TM system, type PFMA 4000, collection rate of 100Hz). Based on the displacement of the center of pressure variables analyzed were: Ellipse Area of 95 (A95), Mean Velocity (MV). Data were tested (SPSS-v19) for normal distribution using the Shapiro-Wilk test and the U of Mann-Whitney adjustment for non-parametric data (significance level p≤0.05). Results Both investigated groups were similar as regards their anthropometric data. Neither the body mass (p=0.18) nor the body height (p=0.39) differentiated between the RG and non-AT. Moreover, significant differences were observed when comparing groups for MV, but not for A95, in all conditions. Interestingly, RG showed greater values of MV than non-AT in all conditions, although both groups had comparable values of surface A95. In absence of vision (EO vs EC), both groups significantly increased theirs MV, but there was a trend to be weaker this effect in gymnasts. Conclusions Expertise in RG did not seem to improve postural strategies compared with non-AT young females. This result is in accordance with other authors that supported the idea that improvement of performance due to learning is specific to the task and not directly transferred or generalized to more usual upright stance in young females. The level of a given athlete in his activity does not implicate a corresponding level in performing usual postures (Asseman, et al., 2004).

EXPERTISE AND STRATEGIES ON POSTURAL CONTROL OF YOUNG SURFERS AT DIFFERENT LEVEL OF COMPETITION

Background Investigation of postural control in sports which require excellent postural performance, like surfing, gives insight into development of specific control strategies. The aim of the current study was to compare postural performance and strategy between young surfers of different levels of competition (international and national). Methods Twenty surfers were separated in two groups in accordance with their competition level: Ten international level surfers (INT) (17.7±1.7 years; 172.6±8.42 cm; 65.0±10.3 kg; 7.75±3.6 surfing years) and 10 national level surfers (NAT) (15.80±1.75 years; 168.60±12.02 cm; 59.25±12.12 kg; 6.6±3.6 surfing years). Subjects performed a battery of static balance tests under three different conditions: eyes open (EO), eyes closed (EC) and while performing a concurrent cognitive task (modified stroop test -MST). All tests were performed while standing on a platform force (MuscleLab® TM system, type PFMA 4000, collection rate of 100Hz), in bipedal posture, staying as immobile as possible for 30 seconds. Based on the displacement of the center of pressure, variables analyzed were: Ellipse Area of 95% (A95), Mean Velocity (MV) and frequency analysis (fast Fourier transform). Data was tested (SPSS-v17) for normal distribution using the Shapiro-Wilk test and the U of Mann-Whitney adjustment for non-parametric data (significance level p≤0.05). Results Both groups showed significantly greater values for MV when comparing the effect of the condition to the control test, EO vs. EC (p=0.007), and EO vs. MST (p=0.027). However, no differences were found in either of the variables when level of competition was analyzed. Although, INT showed smaller values of MV and A95 in all tests, except for A95 in the MST condition, evidencing better postural control (Palliard et al., 2006). Mean Velocity values for INT were: 17.1±3.9; 19.6±3.9; 19.5±7.2 mm/s2, and for NAT were: 18.7±3.3; 21.6±4.4; 21.2±7.2 mm/s2, for EO, EC, and MST condition, respectively. Values of A95 for INT were: 137.9 ±100.9; 148.1±58.7; 158.2 ±117.9 mm2 and for NAT were: 141.9±44.9; 260.2±209.20; 138.6±55.9 mm2, again for EO,EC and MST. In respect to the spectral analysis, INT showed a trend to use a greater portion of energy in the low frequency band in all conditions. Conclusions Our results could indicate that experience in the surfing environment may result in specific strategy adaptation, by means of a more efficient visio-vestibular input (Chapman et al., 2008). A better understanding of these strategies can help athletic trainers and clinicians to develop exercises in an attempt to enhance performance, reduce risk of musculoskeletal injuries or for rehabilitation therapies purposes.