Approximately 70% of penalty kicks in men’s professional football are scored, hence being decisive in increasing the chances of winning, since matches have only 2.5 goals on average. This study assesses the improving chances for the goalkeeper to save penalty kicks, using actual shot speeds in computer simulation and considering actual and experimental data. Simulated kicks were directed at the goal divided in nine areas. The goalkeeper’s movement was chosen to start at five different times before, at and after the instant of the kicker’s impact on the ball. Chances of saving were analysed through logistic regression taking into account area of the goal, ball speed and moment of goalkeeper’s reaction. Saves were found to depend essentially on the beginning of the goalkeeper’s motion according to the area. In the central areas of the goal, saves were statiscally independent of ball speed and time of reaction. The goal region further away from the centre, where real shots are frequently saved, presented highest dispersion. This suggests that saves depend mainly on the goalkeeper’s reaction time but also on the ball speed. Finally, chances are low (but not inexistent) near the posts.

Jump performance is related to the ability of lower limb muscles to produce power during the push-off phase. However, it is not known if the power associated with the action of active and passive elements of the lower limb muscles change significantly in jumps with positive and negative loads. In this study, the power associated with the action of passive and active components of lower limb muscles as a whole in squat jumps (SJ) with increase and decrease in the external load is analyzed Fourteen trained male subjects (22.5 ± 2.1 years; 176.5 ± 5.4 cm; 75.8 ± 5.8 kg; BMI 24.3 ± 1.8) performed SJ on a force plate. A functional electromechanical dynamometer (FEMD) system was used to change the external load in a range of −30 to +30% of the subject’s body weight. A model comprising a mass, a spring, an active element, and a damper was used. We applied an optimization principle to determine power in center of mass (CoM) (ptot), the powers associated with active element (pact), damper (pƔ), and spring (pk) during the push-off phase. Significant differences between loading conditions for each variable were tested by repeated-measures one-way ANOVA with Bonferroni post hoc analysis, p < 0.05. Shapes of the average curves for instantaneous variation of pact, pƔ, pk, and ptot during push-off with positive loads were closer to 0% than with negative loads. As the load increased, maximum values of ptot, pƔ, and pk decreased. Only with a negative load of −30% did ptot increase significantly, this was not accompanied by changes in pact, pƔ, and pk. The load of one’s own body provides conditions for develop high pact peaks, although the maximum ptot is not achieved in that condition. The increase in negative loads produces a significant increase in ptot, but not in pact and can be interpreted as a situation in which the power delivered to the system by the action of active components is better used. The SJ with positive load, although more similar to the instantaneous changes that occur to the SJ with body weight are not gestures where high power is developed.

The speed and angle of ball throwing in handball penalty were measured and the effects of the muscular fatigue and the differential tasks implied in the different field positions on these variables were studied. The ball thrown by ten players of the female Uruguayan national handball team were 2-D kinematically analysed in the lateral plane. Ball speed and output angle were analysed taking into account the match time and the player’s position, either back or wing, using paired sample t-test (p<0.05). A significantly higher speed (p=0.0006) during the first half of match time, compared to the second, was found. Significant difference in the speed according to the position in the field was also warranted (p=0.00015), with backs throwing faster than wings. The throwing angle showed no differences for match time and position (p=0.43 and p=0.63, respectively). The variation in speed during the match could be due to the effect of the increase in muscular fatigue. The difference found for this variable according to the field position is congruent with the function players carried out during the match. The small variations in the shot angles are interpreted as indicative of technique predominance not affected by muscular fatigue.

The aim of this article was to understand how active power is used in squat and countermovement jumps. A simple empirical model comprising a mass, a spring, an active element and a damper, together with an optimisation principle, was used to identify the mechanical factors that maximise performance of jumps without countermovement (squat jumps, SJ) and with countermovement (CMJ). Twelve amateur volleyball players performed SJ from two initial positions and CMJ with two degrees of counterbalancing, while kinematic data were collected (jump height, push‐off duration and position of the centre of mass). The model adjusted well to real data of SJ through all the impulse phase, and slightly less adequately at the end of this phase for CMJ. Nevertheless, it provides a satisfactory explanation for the generation and utilisation of active power for both type of jumps. On average, the estimated power of the active elements, the spring, and the damper were greater in the SJ. Based upon the result obtained with this model, we suggest that active power is best evaluated with SJ. The reason for this is that, during this kind of jump, the elements associated with the damper consume much of the energy produced by the active elements. The participation of the elements that consume the energy generated by the active elements is less in CMJ than in SJ, allowing for a better utilisation of this energy. In this way it is possible to achieve a better performance in CMJ with less active power.