Comparison of Knee Joint Kinematics between Generic and Sport-Specific Agility Tests in Youth Basketball Players

Purpose: Basketball is a popular sport, characterized by short and rapid changes of direction (COD), such as dribbling movements. The majority of agility tests used in basketball players focused only on kinematic analysis of generic agility skills. However, these tests do not assess the kinematics during sport-specific movements, which are highly present during matches and training sessions. Thus, the aim of this study was to compare the COD kinematics between a generic and sport-specific agility test in basketball players under 13 years old. Methods: A total of 21 basketball players (mean age 12.2 ± 0.3 years) were enrolled in this study. All players were tested on the same day after a proper 10-min warm-up. Each player performed two agility tests: a V-cut dribbling test without a ball (generic agility test) and with a ball (sport-specific agility test). The tests consisted of a 25- meter sprint with 4 CODs of 45 every 5 m. The kinematic data were collected using a set of 17 inertial sensors (Xsens MTw Awinda). The kinematic parameters analyzed were the minimum and maximum peaks, and the range of motion (ROM) of adduction-abduction (AA), flexion–extension (FE), and internal–external rotations (IE) of the knee joint. In the analysis, the term ‘‘pivot leg’’ refers to the leg responsible for pivoting, while ‘‘non-pivot leg’’ refers to the contralateral leg. All the kinematic variables were compared between the tests using a paired T-test. A p-value lower than 0.05 was considered statistically significant. Results: The basketball players showed no differences in the knee ROM of each kinematic parameter of the pivot leg between the generic and sport-specific agility tests (p[0.05). The non-pivot leg showed the same results except for the flexion–extension ROM, which was higher in the agility test performed without the ball (p\0.01). In addition, during the COD, the non-pivot knee showed higher extension peaks in the agility tests without the ball (p\0.05). Conclusions: The findings of this study indicate that the presence of a ball during agility tests does not significantly affect the knee ROM of the pivot leg in young (under 13 y.o.) basketball players. However, the non-pivot leg exhibits greater flexion–extension ROM and higher extension peaks when performing agility tests without the ball.