抄録
The purpose of this study is to observe the jump height from preparatory to match periods and investigate the effect of changes in physical activity volume on jumping performance in female collegiate volleyball players. The sample data of thirty-four players (Age: 19.1±1.0, Height: 168.0±5.9cm, Weight: 63.2±6.2kg) was obtained from the KANTO divisionIwomen collegiate volleyball league in the 2018 autumn and 2019 spring and autumn periods. The physical activity was recorded daily during volleyball training using Active Style Pro HJA-750c (OMRON co.). Other than the measurements of body composition, counter-movement jump (CMJ) and CMJ with arm swing (CMJ-AS) were completed by preparation (Pre and Post1) and match periods (Post2 and Post3). Furthermore, the sample data was classified as decrease and maintain groups based on the ratio of changes in jump height from Pre to Post1. The results revealed that physical activity was highest in Post1 and decreased by approximately 50% in Post2. The jump height was considerably lower in Post1 than in Pre but remarkably higher in Post2. In the comparison between the decrease and maintain groups, the physical activity volume of Post1 was more common in the decrease group than in the maintain group. These findings revealed that the jumping performance of female collegiate volleyball players is influenced by the increases and decreases of physical activity volume during volleyball training.
https://ror.org/04r69jb93 
