The purpose of this study is to highlight the evolution of the explosive strength in the 4-year interval of the backs compartment and the level of adaptation to the game requirements. The hypothesis in this study is that the explosive strength of the lower limbs in rugby backs developed during the past 4 years, trying to keep up with the higher needs in the first Romanian league. Explosive power was measured using the ‘Just Jump System’, which is a plyometric test mat on which the players conducted a set of three tests: squat jump, control movement jump and free jump. The forwards significantly improved their explosive strength in a 4-year period. Although the total body mass got bigger, the players managed to improve their lower limbs’ explosive strength; this fact proves a good physical adaptation to the requirements of the rugby game.   Keywords: Power, jump.

The present study aims to identify if and how motor skills such as speed and agility can be improved by using training activities corresponding to performance in volleyball. The experiment included a total of 16 male athletes (17–18 years old), divided into two groups (control and experimental group). The tests applied in the research were the Illinois test and the Hexagon test, since speed, agility and quickness are essential to high performance in volleyball. After the initial tests, the experimental group became part of a 6-week training programme, designed to learn and master speed and agility drills. The results obtained at the final control tests demonstrated that the indicators of motor skills registered a real progress. This confirmed our working hypothesis stating that physical exercises, motor games and other means, specific to the game of volleyball, can influence the development of motor skills.   Keywords: Agility, speed, performance sport, Illinois test, Hexagon test, volleyball training.