教育部报告指出2020年中小学生肥胖率超过10.4%，体质逐年下滑。党和政府高度重视，多次下发相关文件旨在改善目前现状。现有大量的研究表明，联合运动能够有效改善学生体质，但目前大部分联合运动主要是集中在抗阻联合有氧、抗阻联合专项。在HIIT联合抗阻方面的文献较少。本文采用循环抗阻训练联合高强度间歇训练作为干预手段，抓住力量素质和耐力素质发展的关键期，并应用在初三年级。探究此练习对初三学生身体形态、速度、心肺耐力、力量、柔韧等身体素质有何影响，促进学生体质健康。

本研究所采用的方法主要有文献资料法、数理统计法、实验法。选取40名初三学生随机分成实验组（n=20）和对照组（n=20），分别进行十周的训练。实验组首先进行循环抗阻训练，再进行高强度间歇训练。对照组首先进行传统抗阻训练，然后再进行高强度间歇训练。对比训练前后身体形态（BMI、肱三头肌皮褶厚度、腹部皮褶厚度）、力量素质（立定跳远、引体向上/仰卧起坐）、耐力素质（800米/1000米）、速度素质（50米）、柔韧素质（坐位体前屈）的数据变化。通过10周的训练，实验组在BMI、肱三头肌皮褶厚度、腹部皮褶厚度方面显著降低（p＜0.05），立定跳远、仰卧起坐、引体向上、800米、1000米、50米方面显著提高（p＜0.05），坐位体前屈方面不存在显著差异（p＞0.05）。对照组在BMI、肱三头肌皮褶厚度、腹部皮褶厚度方面显著降低（p＜0.05），立定跳远、仰卧起坐、引体向上、800米、1000米、50米方面显著提高（p＜0.05），坐位体前屈方面显著下降（p＜0.05）。实验组对照组实验后各方面均不存在显著差异（p＞0.05）。

本文结论：1.循环抗阻训练配合高强度间歇训练与传统抗阻训练配合高强度间歇训练均能改善学生身体形态，但二者存在不同的效果，前者有利于控制身体质量指数（BMI），后者有利于降低初三学生的体脂肪含量。2.循环抗阻训练配合高强度间歇训练可提高初三学生的力量素质、耐力素质、速度素质，且相较于传统抗阻训练配合高强度间歇训练在改善耐力素质方面效果更好。在改善力量素质、速度素质方面传统抗阻训练配合高强度间歇训练效果更好。3.循环抗阻训练配合高强度间歇训练对学生的柔韧素质没有影响。

According to a report by the Ministry of Education, the obesity rate of primary and secondary school students in 2020 will exceed 10.4%, and their physical fitness will decline year by year. The party and the government attach great importance to it, and have issued relevant documents many times to improve the current situation. A large number of existing studies have shown that joint sports can effectively improve students' physical fitness, but most joint sports currently focus on resistance combined aerobic and resistance combined special projects. There is less literature on HIIT combined impedance. In this paper, circuit resistance training combined with high-intensity interval training is used as an intervention method to seize the critical period for the development of strength and endurance quality, and apply it in the third grade. Explore how this exercise affects the physical fitness of junior three students' physical shape, speed, cardiorespiratory endurance, strength, flexibility, etc., and promote students' physical health.

The methods used in this study mainly include literature, Mathematical Statistics and experiment. Forty junior middle school students were randomly divided into experimental group (n = 20) and control group (n = 20) for ten weeks of training respectively. The experimental group received cyclic resistance training first, and then high-intensity intermittent training. The control group received traditional resistance training first, and then high-intensity interval training. Compare the data changes of body shape (BMI, triceps skinfold thickness, abdominal skinfold thickness), strength quality (standing long jump, pull up / sit ups), endurance quality (800m / 1000m), speed quality (50m) and flexibility quality (sitting body flexion) before and after training.

After 10 weeks of training, the BMI, triceps skinfold thickness and abdominal skinfold thickness of the experimental group decreased significantly (P<0.05), while the standing long jump, sit ups, pull-up, 800m, 1000m and 50m increased significantly (P<0.05). There was no significant difference in sitting forward flexion (P>0.05). In the control group, BMI, triceps skinfold thickness and abdominal skinfold thickness decreased significantly (P<0.05), standing long jump, sit ups, pull-up, 800m, 1000m and 50m increased significantly (P<0.05), and sitting forward flexion decreased significantly (P<0.05).There was no significant difference in all aspects between the experimental group and the control group after the experiment (P>0.05).

Conclusions of this paper:1. Circuit resistance training combined with high-intensity interval training and traditional resistance training combined with high-intensity interval training can both improve students' body shape, but the two have different effects. The former is conducive to controlling body mass index (BMI), while the latter is conducive to reducing Body fat content of junior high school students.2.Circuit resistance training combined with high-intensity interval training can improve the strength, endurance and speed of junior three students, and compared with traditional resistance training combined with high-intensity interval training, it is more effective in improving endurance quality. Traditional resistance training combined with high-intensity interval training is more effective in improving strength quality and speed quality.3.Cyclic resistance training combined with high-intensity interval training had no effect on the flexibility of students.