Reaching higher, landing harder: classifying individualized jump intensity zones and ground impact forces in professional male and female volleyball matches

This exploratory study aimed to (i) develop a framework to classify individualized jump intensity zones by combining relative jump height and landing impact force and (ii) explore sex- and position-based differences using these zones among volleyball players. Twenty-four players (13 male, 11 female) from two professional teams were monitored across the 2024–2025 season. Maximum jump height was determined using a spike jump test with an inertial measurement unit (IMU) for each player. In-match jumps were captured using the same IMU, with jump height and landing force recorded. Jump height was expressed as a percentage of individualized maximum jump height from the spike jump test (or in-match measurement if higher). K-means clustering defined five intensity zones for each sex. Descriptive analyses were conducted according to position (middle blockers, outside hitters, opposite hitters, and setters) and sex. Overall, 17,930 jumps in males and 14,725 jumps in females were analysed during matches. Males demonstrated significantly higher average jump heights (57.2 ± 16.3 cm vs. 41.7 ± 13.0 cm, p < 0.001, g = 1.00) and greater landing forces (10.4 ± 5.1 g vs. 8.4 ± 4.7 g, p < 0.001, g = 0.41) than females. Individualized zones were identified, ranging from very low (~25% of maximum jump height) to very high (~80% of maximum jump height) intensities. Landing impact increased progressively across zones, ranging from approximately 6 g in the lowest zone to over 12 g in the highest zone. Middle blockers and outside hitters accumulated more high- and very high-intensity jumps, while setters exhibited more moderate-intensity jumps than other positions. Males showed higher absolute and relative jump heights as well as greater landing forces than females, although intensity zone thresholds were comparable across sexes. This study introduces a novel and individualized method for classifying jump intensity in volleyball, combining jump height and landing impact forces to reflect mechanical output and stress.