José Campos

KINEMATICAL ANALYSIS OF THE SNATCH IN ELITE MALE JUNIOR WEIGHTLIFTERS OF DIFFERENT WEIGHT CATEGORIES

The purpose of this study was to analyze the differences in the technical pattern of the snatch in elite junior weightlifters of different weight categories. The sample was a group of 33 men weightlifters from different weight categories. The comparative study included 2 groups, taking into account weight categories. Group A included 17 weightlifters from the lightest categories, 56 and 62 kg; group B included 16 weightlifters from the heaviest categories, 85 and 105 kg. Three-dimensional photogrammetry technique was utilized. Regarding group differences, we can conclude that lifters belonging to heavier categories are more efficient, as they manage to have longer barbell propulsion trajectories, which allows them to exert actions on the barbell for a longer period, especially in the initial lifting phase. They attain greater barbell vertical velocity (p = 0.029), a longer vertical bar trajectory normalized on first pull (p = 0.011), and a greater, although limited, bar height loss on the catch (p = 0.008). Besides, intergroup differences evidence that heavier category lifters observe a different temporal organization of the movement based on a longer first pull (p = 0.000), a shorter transition (p = 0.030), and a longer turnover (p = 0.049). No significant differences were found in the analyzed angular parameters during the first and second pull. We believe the intergroup differences found not to be determining enough to consider a technical model adapted to the characteristics of each body weight category. This confirms that a successful lift is multifactor based and individual dependent. Given its transcendence, this evidence should be taken into account in the technical training of young lifters.

Anticipatory strategies of team-handball goalkeepers

Abstract This study seeks to discover whether handball goalkeepers employ a general anticipatory strategy when facing long distance throws and the effect of uncertainty on these strategies. Seven goalkeepers and four throwers took part. We used a force platform to analyse the goalkeepers movements on the basis of reaction forces and two video cameras synchronised at 500 Hz to film the throw using 3D video techniques. The goalkeepers initiated their movement towards the side of the throw 193 ± 67 ms before the release of the ball and when the uncertainty was reduced the time increased to 349 ± 71 ms. The kinematics analysis of their centre of mass indicated that there was an anticipatory strategy of movement with certain modifications when there was greater uncertainty. All the average scores referring to velocity and lateral movement of the goalkeepers centre of mass are significantly greater than those recorded for the experimental situation with bigger uncertainty. The methodology used has enabled us to tackle the study of anticipation from an analysis of the movement used by goalkeepers to save the ball.

A Comparison of Two Landing Styles in a Two-Foot Vertical Jump

Gutiérrez-Davila, M, Campos, J, and Navarro, E. A comparison of two landing styles in a two-foot vertical jump. J Strength Cond Res 23(1): 325-331, 2009-In team sports, such as basketball and volleyball, the players use different takeoff styles to make the vertical jump. The two-foot vertical jump styles have been classified according to the landing style and identified as hop style, when both feet touch the ground at the same time, and step-close style, when there is a slight delay between the first and second foot making contact with the ground. The aim of this research is to identify the differences between the two styles. Twenty-three subjects participated in the study, of whom 14 were volleyball players and 9 were basketball players. The jumps were video recorded and synchronized with two force platforms at 250 Hz. Two temporal periods of the takeoff were defined according to the reduction or increase in the radial distance between the center of gravity (CG) and the foot support (T - RDCG and T + RDCG, respectively). The findings produced no specific advantages when both styles were compared with respect to takeoff velocity and, consequently, to jump height, but takeoff time was significantly shorter (p < 0.001) in the hop style takeoff. However, this reduction was compensated for by the greater time employed in the last step of the approach run (p < 0.001). When the step-close style was used, the vertical velocity of CG at the beginning of the takeoff is significantly lower. Moreover, the mean vertical force developed during T − RDCG was reduced by −627.7 ± 251.1 N, thus lessening impact on landing. Horizontal velocity at the end of the takeoff is less when the step-close style is used (p < 0.005), suggesting that this style is better for jumps where it is necessary to move horizontally during the flight against an opponent.

Distribution competence of a football clubs goalkeepers

Much of the existing goalkeeper (GK) research is based around GK’s performance but not with a match analysis theme. Research has focused on physiology, psychology and injury prevention. Performance analysis based GK research will significantly increase the standards of GK performance by increasing the knowledge we have of a GK’s match demands. As a consequence of this lack of knowledge surrounding GK’s distribution performance the aim of this study was to increase the understanding of GK’s performance through their distribution performance and to see if the level in which they compete influences this. The subjects used in this study were all professional GK’s from the same club, they were all the first choice GK’s from the clubs 4 most senior teams. The study analysed the GK’s distribution performances through Distribution Location, Type, Success and Outcome data. Results found that there were significant differences (P<0.05) in the GK’s Location, Type and Success of distributions. This research has found that the GK’s did indeed perform differently and that GK’s do truly perform to better standards as their level of competition increases, this is shown by performing simpler tasks to a near perfect standard and performing more difficult tasks well.

Biomechanical Analysis of Anticipation of Elite and Inexperienced Goalkeepers to Distance Shots in Handball

Abstract The objective of this study was to evaluate the anticipation time and kinematic factors in the movement of goalkeepers’ center of mass when making a long-distance throw in handball. The sample group was composed of 14 goalkeepers and field players. A force platform was used to measure the force of the goalkeepers’ reaction movements, while the throwers’ movements were recorded with high-speed cameras. The expert goalkeepers began to move 193 ± 67 ms before the ball was released, with a 67% success rate of interception. The inexperienced goalkeepers began their movement 209 ± 127 ms with a 24% success rate. The time taken by expert goalkeepers to begin a vertical movement of their CM, relative to the moment of the ball’s release, was less than the time taken by inexperienced goalkeepers (77 ± 70 vs. 141 ± 108 ms respectively). The analysis of the velocity and movement indicates that expert goalkeepers wait longer before moving than do inexperienced goalkeepers.

Three-Dimensional Kinematics During the Take-Off Phase in Competitive Long Jumping

The purpose of the present study was to identify the relationships among selected kinematic variables that affect the take-off phase and performance in elite jumpers. The jump distance was found to be related to: I) the athletes approach speed before the instant of touch down; and ii) the exchange in spatial velocity components at take-off, which results in a gain in maximum vertical velocity of the centre of mass (CM), favoured by the use of an optimum touch-down angle of the take-off leg, an active landing of the foot at touch-down, and a motion of the take-off leg during the compression phase that helps to manage the loss of horizontal velocity. Nonetheless, the results show that an adequate velocity transformation requires an adaptive technical model to help jumpers to build an efficient individual technical pattern.

The inside out forehand as a tactical pattern in men’s professional tennis

Abstract The so-called inside out forehand has an active role in the baseline strategy because it offers the players new possibilities of hitting the incoming ball with their preferred shot by covering their weaker side and, at the same time, playing the ball with more open angles and directions which create more aggressive patterns of play. The purpose of this study is to analyse the use of this shot as well as its incidence on the men’s professional game both, right- and left-handed players. Eighteen matches corresponding to Grand Slam and ATP finals played between 2011 and 2014 were analysed. Eleven players (men) with ATP rankings between 1 and 14 were studied. Data show that the inside out forehand is used as a tactical weapon to counter the shots directed to the left-hand side zone of the court. The use of the inside out forehand has multiple consequences and, especially, the relationship between the use of the inside out forehand and the impact zone since it has been shown that as the player moves away laterally from the centre of the court, the percentage of transition shots is reduced, while the percentage of winners and errors increases.