The aim of the study was to assess the relationship between reactive agility and change of direction speed (CODS) among amateur soccer players using running tests with four directional changes. Sixteen amateur soccer players (24.1 ± 3.3 years; 72.4 ± 7.3 kg; 178.7 ± 6 cm) completed CODS and reactive agility tests with four changes of direction using the SpeedCourt™ system (Globalspeed GmbH, Hemsbach, Germany). Countermovement jump (CMJ) height and maximal foot tapping count (completed in 3 seconds) were also measured with the same device. In the reactive agility test, participants had to react to a series of light stimuli projected onto a screen. Total time was shorter in the CODS test than in the reactive agility test (p < 0.001). Nonsignificant correlations were found among variables measured in the CODS, reactive agility, and CMJ tests. Low common variance (r = 0.03-0.18) was found between CODS and reactive agility test variables. The results of this study underscore the importance of cognitive factors in reactive agility performance and suggest that specific methods may be required for training and testing reactive agility and CODS.

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Arm swing improves vertical jump height but the underlying mechanism is not well understood. We assume that the negative acceleration of arm swing can increase the load and tension of the lower limb's extensor muscles enhancing force output and resulting in higher jump. The purpose of this study was to examine how arm swing affects the EMG activity of the lower limb muscles during vertical jumping in relation to the arm swing kinematics.Sixteen physically active male college students were asked to perform squat (SJ) and countermovement jumps (CMJ) with arms akimbo and with arm swing. Jumps were carried out on a force platform while kinematic data and EMG activity of the right lower limb were measured.Jumping height increased by 33% in SJ and by 18.9% in CMJ when performed with arm swing. In SJ with arm swing the vertical ground reaction force (GRF) was larger during the negative acceleration of the arm (71-91% of the jump, p < 0.001) with significantly slower relative joint extension. Similarly, in CMJAS during the negative acceleration of the arm vertical GRF was larger (89-97% of the jump, p < 0.001) compared to CMJ. Arm swing increased the jump time, net impulse and take off velocity in both jumps. No differences were detected in EMG between jumps carried out with and without arm swing.When jumps carried out with arm swing, we can observe higher vertical GRF during the negative acceleration of the arm swing that indicate higher load on the lower limb, but we cannot confirm our initial idea with the results of the EMG comparison. Increase in jump height can be explained by the extended jump time resulting in greater mechanical variables in jumps with arm swing.

The aim of the study was to develop and assess the reliability of a functional agility test containing offensive elements for water polo players. Eighteen young male (15.3 ± 0.5 years, 178.3 ± 4.7 cm, 69.4 ± 10.0 kg) water polo players with a minimum of 5 years of sport-specific experience participated in this study. The test contained reactive high-intensity short-term swimming with changes in direction and manoeuvres after perceiving unknown stimuli given by tester players, and also included a shooting task at a goal, first from 7 m and then from 5 m. Execution time and shooting efficiency were measured by two experienced water polo coaches (Evaluators A and B). All statistical analyses were calculated using SPSS. The intrarater reliability between attempts showed good reliability for both evaluators (Evaluator A: ICC: 0.87; 95% CI: 0.66–0.95 and Evaluator B: ICC: 0.88; 95% CI: 0.68–0.96). Interrater reliability between Evaluators A and B was excellent at both attempts (Attempt 1: ICC: 0.97; 95% CI: 0.93–0.99 and Attempt 2: ICC: 0.98; 95% CI: 0.91–0.99). A lack of correlation between shooting performance from 7 m and 5 m distances and execution time was observed in the protocol. The test we presented in this study was found to be a reliable measurement tool for testing offensive agility performance based on open skill nature among water polo players.