Understanding the developmental levels of fundamental movement skills has a critical role in the improvement of motor competence in childhood. In this respect, the use of Microsoft Kinect to assess vertical jumping skill and to predict developmental levels in 9- to 12-yr.-old children was evaluated. 41 boys and girls repeated the countermovement jump test three times. Vertical jumping skill levels were categorized using observational records, while kinematic and temporal parameters were estimated using a biomechanical model based on data acquired by the Kinect. Multivariate analysis of variance (MANOVA) and discriminant analysis verified that the height of the jump and the flight height predict the primary differences in jumping skill developmental levels, and the Kinect-based assessment discriminates these levels.

This study tested the feasibility of using an inertial measurement unit to discriminate different developmental levels of children performing the standing long jump (SLJ). Sixty-four children (54.6% boys, 46.4% girls) aged 8 to 11 years old (M ¼ 9.17, SD ¼ 0.97) performed the SLJ three times and were classified by rater observations into three developmental levels. Concurrently, they wore an inertial measurement unit from which a set of temporal and kinematic parameters for the quantitative assessment of their jumps. A multivariate analysis of variance revealed that variability among the developmental groups was identified by the overall set of parameters, while discriminant function analysis verified that these parameters discriminated among developmental levels. Primary predictors for developmental group discrimination were maximum peak acceleration in the vertical and anteroposterior directions, respectively, and normalized preparation time. These outcomes represent significant steps toward improving the assessment of SLJ rate of development in childhood and supporting physical education.

Tennis serve is a closed-skill motion influenced by the kinematic chain concept. An important role on the final performance is surely linked to the knee joint motion, although only few studies addressed lower-limb influence. In this work we propose a study about the proprioceptive angle size of knee joint in the first flat serve produced by tennis players of different performance levels. Twelve subjects involved in the study are divided in three groups using the ITN classification code: beginner, intermediate and advanced players. A simple biomechanical model of lower limb was proposed to study the knee joint motion. Three flat serves were recorded using three synchronized cams. A specific algorithm was developed to obtain the maximum flexion value of front knee using coordinates of lower-limb joints. Speed of impact (S B ) and height of impact (H B )were also evaluated to compare results with previous works and to assess the tennis players' performance. Results showed a statistical meaningful difference among three groups in all performance indexes. Moreover a strong correlation was found among knee motion and S B and H B .

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