本研究以长期跑步锻炼作为干预手段，观察在不同干预时间内对大学生体成分和体能的影响，基于测试结果，并系统性地研究不同群体之间的共性与不同，为大学生跑步锻炼提供更加系统全面的科学指导方案。本研究使用了文献资料法、数理统计法和实验研究法。以大学生跑步爱好者（实验组）和普通大学生（对照组）为研究对象。选取清华大学中长跑一队，中长跑二队21人进行实验干预，73名普通大学生为对照组，受试者均为男性。对实验组进行为期6个月和12个月的长跑训练，观察其对体成分、体能指标的影响。体成分测试使用生物电阻抗法，体能测试包含有氧耐力、平衡能力、柔韧性、核心力量、下肢力量等指标。研究结果：大学生跑步爱好者和普通大学生之间体成分存在较大差异， 6个月的干预时间内实验组的变化集中在身体代谢方面，主要为细胞内液ICW和细胞外液ECW的增加，以及肌肉含量的显著性增加；12个月的长跑训练对大学生跑步爱好者体成分的影响效果更加显著，主要表现为肌肉和去脂体重指标显著增加，P＜0.05（P=0.026，0.017）；蛋白质含量增加，P＜0.01（P=0.009）；脂肪重量和体脂率出现明显下降，脂肪重量P＜0.05（P=0.011），体脂率P=0.01；体能方面为6和12个月的长跑训练使核心力量下降，但是皮褶厚度降低，P＜0.05（P=0.022）；3km成绩快速提升，P＜0.01（P=0.006），表明有氧能力显著提升。研究结论：长期跑步运动对大学生体成分有积极改善，能有效减少体内脂肪含量和体脂率，同时增加肌肉含量，改善身体代谢，锻炼时间越长，效果越明显；长跑训练对体成分的改变受到运动量、运动强度以及每周锻炼频次等因素的影响；长跑训练会使有氧能力得到快速提升，但是核心力量也容易随之下降，在日常的跑步训练中应该综合考虑耐力和力量的融合，按照个性化原则制定合适的训练计划。同时也应依据不同阶段的目标，合理配比力量和耐力的训练占比。

This study takes long-term running exercise as an intervention means to observe the influence of different intervention times on the body composition and physical fitness of college students. Based on the test results, the similarities and differences among different groups are systematically studied to provide a more systematic and comprehensive scientific guidance program for college students‘ running exercise.This study uses the method of literature, mathematical statistics and experimental research. College runners (experimental group) and ordinary college students (control group) were selected as the research objects. Twenty-one students from the Middle and long distance running team and the second middle and long distance running team of Tsinghua University were selected for the experimental intervention, and 73 ordinary college students were the control group, all of whom were male. The experimental group underwent long-distance running training for 6 months and 12 months, and the effects on body composition and physical fitness were observed. The body composition test uses the bioresistance method, and the physical fitness test includes indicators such as aerobic endurance, balance, flexibility, core strength, and lower limb strength.Results: There were significant differences in body composition between college runners and ordinary college students. The changes in the experimental group during the 6-month intervention period were concentrated in body metabolism, mainly the increase of intracellular fluid ICW and ECW, and the significant increase of muscle content. 12 months of long-distance running training had more significant effects on body composition of college runners, mainly manifested as significant increases in muscle and fat-free body mass index, P < 0.05 (P=0.026, 0.017); Protein content was increased, P < 0.01 (P=0.009); Fat weight and body fat percentage decreased significantly, fat weight P < 0.05 (P=0.011), body fat percentage P=0.01; In terms of physical fitness, 6 and 12 months of long-distance running training decreased the core strength, but the skin fold thickness decreased, P < 0.05 (P=0.022); The results of 3km were improved rapidly, P < 0.01 (P=0.006), indicating a significant increase in aerobic capacity.Conclusion: Long-term running can positively improve the body composition of college students, effectively reduce body fat content and body fat percentage, increase muscle content and improve body metabolism, and the longer the exercise time, the more obvious the effect; The change of body composition of long-distance running training was affected by the amount of exercise, the intensity of exercise and the frequency of weekly exercise. Long-distance running training will make aerobic capacity get rapid improvement, but the core strength is also easy to decline, in the daily running training should consider the integration of endurance and strength, in accordance with the personalized principle to develop a suitable training plan. At the same time, the training proportion of strength and endurance should be reasonable according to the goals of different stages.