Individualized Physical Performance Metrics in 3 × 3 Basketball Games Using Match-Play Data

3 × 3 basketball is a high-intensity intermittent sport practiced by both professional and recreational athletes. However, the use of predefined absolute thresholds to quantify external load may overlook meaningful inter-individual differences in movement intensity. This study examined internal and external load demands during official 3 × 3 match play using individualized, performance-based load zones. Seventeen male players were monitored across 38 valid match observations during a two-day tournament. External load was collected via inertial measurement units, while internal load was assessed through continuous heart-rate monitoring. Raw triaxial accelerometer data were processed in Python to remove gravitational components and reconstruct speed–acceleration profiles, allowing identification of individual acceleration, deceleration, and jump events. Statistical analyses were conducted using linear mixed-effects models with Bonferroni-adjusted post hoc comparisons to evaluate differences between absolute and individualized zones. Players sustained high physiological strain, operating at approximately 85–90% of HRmax, and performed frequent high-intensity mechanical actions. Individualized acceleration, deceleration, and jump zones yielded a more even dispersion of events across low-, moderate-, and high-intensity categories. In contrast, predefined absolute thresholds classified over 90% of events as low intensity, masking meaningful variability. These findings highlight substantial inter-individual differences in 3 × 3 match demands and support the use of individualized load profiling for accurate monitoring, performance evaluation, and training prescription.