The aim of this study was to determine the reliability of the squat jump test (SJ) and countermovement jump test (CMJ), in fifty-six children (30 girls and 26 boys) with ages ranging from 6 to 8 years. Each subject performed two evaluation sessions (T1, T2) with seven days between tests. The results show that the CMJ test has a high intratrial reproducibility in T1 and T2 measured through intraclass correlation coefficient (ICC ≥ 0.95). The ICC for the SJ test had a high value (0.99) only in T1. The variability for both tests among children under 9 years of age is higher than those reported for adult subjects in other studies. The intersession reliability was questionable with a high methodical error (ME= 9.86-15.1%, for the SJ and CMJ, respectively) and a significant worsening of the results of CMJ in T2 (p < .05).

Abstract:Kicking ability in soccer has been evaluated predominantly by the maximum ball velocity. The kicking deficit (KD) may be defined as the percentage of the difference between the maximum ball velocity each player achieved by the non-preferred leg kick in relation to the preferred leg kick. This study aimed to compare: side-to-side kicking velocity, vertical jumps and anthropometrics between the younger (G-14) and older (G+14) than 14 years soccer players. An additional aim was to investigate associations among these variables. Participants were 92 young elite soccer players from the development programme of a top Spanish division club. They were divided into two age groups according to their growth and motor development stages (10.80-13.55 years, n=46; 14.02-16.39 years, n=46). Student's t-test showed that the maximum kicking velocity with the preferred and non-preferred leg, jumping performance, and all anthropometric measurements were significantly (p<.01) higher in G+14 compared with G-14. In contrast, KD values remained stable (15.31%-15.83%) without significant differences between the groups. Pearson's correlation analysis revealed that vertical jump tests and anthropometric measurements correlated with kicking ball velocity produced by the preferred and non-preferred leg. Our results demonstrate that kicking skills are still not consolidated and power factors may be determinant for kicking performance in young soccer players. In addition, the KD may be a constant element for both the under and above 14 years soccer players and could result from an unequal and greater use of the preferred leg in comparison with the non-preferred leg.

In this paper we review the most significant studies that deal with the motor enablement experienced by patients with Parkinson's disease in the presence of external rhythmic auditory or visual signals; the different possible causes underlying this enablement are also discussed. Development. The improvements to movement that can be achieved using external stimuli in patients suffering from Parkinson are well documented in the literature. This is why sensory stimulus has become one of the most important points of reference within the rehabilitative strategies that attempt to alleviate the motor difficulties these patients display. Yet, the neurophysiological mechanisms underlying this sensorial enablement have still to be determined. Conclusions. The data we currently have available allows us to consider this type of technique as a useful instrument for improving the motor autonomy of patients with Parkinson and which should be taken into account by health care professionals.