Characteristics of High-Impact Movements Observed in High School Handball Players During Games.

Background: In handball, injury occurs more frequently during actual games than during handball practice. However, mechanical loading during actual games is unknown. Purpose: The purpose of this study was to describe body impact characteristics during handball games using accelerometers, and to investigate sex differences in these characteristics. Study Design: Comparative observational study. Methods: Acceleration data were measured during practice games in 24 high school handball players (12 males, 12 females). The acceleration was set to 1 gravitational acceleration (G) when each axis direction was aligned with the direction of gravity during data collection. High-impact movements with a resultant acceleration of ≥ 6G were extracted, and video images was used to identify movements and plays during which the high-impact movements occurred. The number of cases, percentage, frequency (cases/min ･ person), and 95% confidence interval of the frequency were calculated for the movement classification, play classification, and movement classification × play classification. The peak acceleration values of resultant accelerations of ≥ 6G were also obtained. Results: The frequencies of resultant acceleration ≥ 6G were 5.3 cases/min ･ person for males and 4.7 cases/min ･ person for females. Deceleration and sprinting were the most frequent motion categories in both sexes. High-impact movements were more frequent in fast attack-related play in males and attack-to-defense transitions in females. Conclusion: High-impact movements are more frequent in plays related to fast attacks in males and when switching from attack to defense in females. High-impact movements are more likely to occur during the switch from attack to defense in females. Level of evidence: 3.