Nowadays, more and more college students’ physical health is getting worse because of their living habits and self-consciousness. In order to improve the physical quality of college students as much as possible, the experiment uses the improved iterative dichotomiser III (ID3) decision tree to make decisions on the physical condition of some college students and the corresponding sports mode recommendation, and compares the results with the traditional ID3 algorithm. In the experimental results, the information entropy ratio of the improved ID3 algorithm is 89.5%, the operation information loss rate is 4.136%, and the accuracy of motion mode decision is 92.58%. The average relative time is 12.7, and the accuracy of physical health decision making is 90.02%. The above two values are not significant compared with the traditional ID3 algorithm. The experimental results show that the improved ID3 algorithm has significant optimization in the stability of information transmission and the accuracy of sports recommendation decision making, and can be applied to the physical health evaluation and sports recommendation of college students in a certain range.

The study compared different training modalities, such as high-intensity interval training versus continuous endurance training, on selected health-related physical fitness, biochemical and haematological parameters of teenage players yielding similar mechanical work and training duration. A random sampling technique was employed and affirmed by the Ethical Committee of Sichuan Province, China. Forty-five teenage sports players aging 18–19 from Sichuan Province, China, were categorized into two experimental and one control group (n = 15) subjects. The groups were allocated separately to high-intensity interval training, continuous endurance training, and control group for a three-month physical exercise program. Each group’s training intensity was set based on the resting heart rate, to assess the effects on health-related physical fitness using fitness gram variables such as cardiovascular endurance, muscular endurance, and flexibility. Biochemical and haematological fasting blood samples were taken and tested at baseline and post three months of training. Detailed descriptive statistics were carried out for the interpretation of the data. All the statistical analysis was completed using the IBM SPSS 20. Paired t-test and one-way ANCOVA were used to evaluate the effect of two aerobic training methods, and to determine the exact difference between the groups, Scheffe’s post hoc test was employed. The result of the study shows that cardiovascular endurance in HIIT showed a better performance of (25.6%) than in C.E.T. (18.1%). Regarding muscular endurance, C.E.T. achieved 19.6% and HIIT 16.2%. For flexibility, HIIT improved by (6.5%) while C.E.T. (5.8%). Accordingly, the study revealed significant changes in teenage sports players’ health-related fitness, biochemical and haematological parameters.