橄榄球运动是一项运动强度大、对抗激烈且极具观赏性的球类运动项目。七人制橄榄球比赛由于比赛时间短，比赛强度和难度大大增加，防守水平很大程度上会决定比赛结果。以往研究关于橄榄球防守的研究大多仅对橄榄球运动中Tackle、Scrum、Ruck和Maul等技术进行描述统计，有关比赛中球队防守特点尚不清楚，因此，探讨第十八届亚运会女子七人制橄榄球四强队伍的防守特点，不仅可优化我国女子七人制橄榄球战术训练，帮助中国队进一步提升防守水平，而且可以弥补橄榄球防守理论研究的不足，进一步完善该项目防守方面的相关理论体系。

本研究综合运用文献资料法、专家访谈法、录像解析法、数理统计法和逻辑分析法，以前人研究成果为基础，通过对国内橄榄球专家的访谈对七人制橄榄球比赛防守形式的概念进行界定、对防守形式进行划分、对运动场区进行划分，在此基础上，解析第十八届亚运会女子七人制橄榄球四强队伍比赛视频，对四强球队在比赛中的防守形式特点、防守技术特点和由攻转守防守特点进行统计与分析，归纳总结日本、中国、哈萨克斯坦和泰国四支队伍的防守特点。

本研究结论如下：

1、从防守形式上，中国队的防守形式以压迫式防守为主，阵线调整能力强，能及时补防；日本队防守形式更灵活，以压迫式防守+横移防守为主；哈萨克斯坦队的防守形式虽然以压迫式防守为主，但是整体防守线不是很整齐；泰国队速度较慢，防守以保持整条线的完整横向移动为主。

2、从不同区域不同防守形式的运用上，中场防守形式的运用最多，前场、后场防守形式运用次数明显比中场低，中国队防守更加积极主动，在前场丢球后能立刻转入防守；四强球队在不同区域防守形式的特征与其整体防守形式的运用一致，中国队、哈萨克斯坦队偏好压迫性防守，日本队偏好压迫性防守与横移防守，泰国队偏好运用横移防守。

3、从防守技术上，四强球队的Tackle技术皆以个人直接Tackle为主，哈萨克斯坦队、泰国队两人以上Tackle的运用次数比中日两队多； Tackle反抢的差异不大，日本队运用Tackle时犯规次数最少；四强球队的Tackle主要集中在中场区域，其中哈萨克斯坦队、泰国队中场的Tackle的时效性较差。

4、从由攻转守的防守上，四强球队都重视开球后的反抢，中国队开球后反抢意识更强，防守更到位；中日两队的Ruck反抢次数最多，犯规次数少，Ruck防守质量更高，四强球队在不同区域的Ruck防守情况并无较大差异；从Scrum出球后的整体防守特点看，中日哈三队都重视压迫防守，泰国队出球后更加重视横向移动防守；从Line-out出球后的整体防守特点看，四强球队特点基本一致，在Line-out出球后都采取压迫式防守的形式。

Rugby is a ball game with high intensity, fierce competition and great appreciation. Because of the short playing time, the intensity and difficulty of the game are greatly increased, and the defensive level will largely determine the result of the game. In the past, most of the researches on rugby defense only described and counted the skills of Tackle, Scrum, Ruck and Maul in rugby, but the characteristics of team defense were not clear. Therefore, to explore the defense characteristics of the top four women's seven player rugby teams in the 18th Asian Games can not only optimize the tactical training of women's seven player rugby in China, but also help the Chinese team to enter the first place Step to improve the level of defense, and can make up for the lack of football defense theory research, and further improve the project defense related theoretical system.

Based on the previous research results, this study defines the concept of defense form, divides the defense form, and divides the playground area through the interviews with domestic Rugby experts, and based on the 18th Asian Games women's seven people Based on the observation of the game video of the top four rugby teams, this paper makes statistics and analysis of the defense form, defense technology and defense characteristics of the top four teams in the game, and summarizes the defense characteristics of Japan, China, Kazakhstan and Thailand.

The conclusions of this study are as follows:

1. From the aspect of defense form, Chinese team's defense form is mainly compression defense, with strong front adjustment ability, which can make up defense in time; Japanese team's defense form is more flexible, with compression Defense + lateral defense as the main form; Kazakhstan team's defense form is mainly compression defense, but the overall defense line is not very neat; Thailand team's speed is slow, and the defense is to keep the whole line The complete lateral movement of the main.

2. From the perspective of the application of different defensive forms in different regions, the defensive forms in midfield are the most frequently used. The number of application of the defensive forms in front field and back field is significantly lower than that in midfield. The Chinese team is more active in defense and can immediately turn to defense after losing the ball in front field. The characteristics of the defensive forms in different regions of the top four teams are consistent with the application of the overall defensive forms. The Chinese team and Kazakhstan team are biased The Japanese team preferred the oppressive defense and the lateral defense, while the Thai team preferred the lateral defense.

3. From the perspective of defensive technology, the four teams' Tackle technology is mainly personal direct Tackle, Kazakhstan team and Thailand team use more than two people's Tackle than China and Japan; There is little difference in the counter attack of Tackle, and the Fouls of Japan team are the least when using Tackle; the Tackle of the top four teams are mainly concentrated in the midfield, among which the effectiveness of Kazakhstan team and Thailand team is poor.

4. From the perspective of defense from attack to defense, the top four teams attach great importance to counter attack after kick-off, and the Chinese team is more aware of counter attack after kick-off, and the defense is more in place; the Chinese and Japanese teams have the most number of counter attack, fewer fouls, and higher quality of Ruck defense, and the top four teams have no significant difference in the situation of Ruck defense in different regions; from the perspective of the overall defense characteristics of Scrum after kick-off, the three teams of China, Japan and Kazakhstan all attach great importance to counter attack According to the oppressive defense, Thailand team pays more attention to the lateral moving defense after the ball is out; from the overall defense characteristics after the line out, the four top teams basically have the same characteristics, and take the form of oppressive defense after the line out.