Assessing the Relationship and Convergent Validity of Player Load and Dynamic Stress Load in Basketball: A Multivariable Regression Analysis

Purpose: This study aimed to assess the strength of the relationship between Player Load and dynamic stress load (DSL); to evaluate the convergent validity between Player Load, DSL, and other external-load parameters in basketball; and to develop multiple-regression models to explain the relative importance of different external-load parameters to Player Load and DSL. Methods: Thirteen male basketball players less than 18 years old (age: 16.9 y, height: 198.1 cm, and body mass: 80.2 kg) participated in this study during the 2023-24 season. Players' physical demands were monitored with a local positioning system that was combined with inertial microsensors (WIMU PRO, RealTrack Systems SL). The accelerometer-derived metrics analyzed in this study were Player Load and DSL and other external-load metrics. Results: Player Load and DSL showed a very large repeated-measure relationship, rm_corr = .781. Player Load showed a relationship with total distance (.967, almost perfect), high-speed running (.687, large), acceleration distance (.680, large), and deceleration distance (.661, large). Dynamic stress load showed a significant relationship with total distance (.662, large), high-speed running (.663, large), acceleration distance (.426, moderate), and deceleration distance (.412, moderate). Conclusions: Player Load and DSL are correlated but not interchangeable. Player Load correlates at least moderately with all external-load measures monitored, with total distance and step count being almost perfect. Although DSL is correlated well with impacts, step count, and jump count over 3 gravitational forces, it correlates to a lesser extent with all metrics. Finally, this study developed 2 multiple-regression models to explain the relative importance of external-load parameters.