According to your age, you should be in high school, so it is very good for you to take time out to run in the playground every day. Do 20 push-ups before going to bed at night and do 1-2 groups; Sit-ups are in groups of 20 and do 2-3 groups.

In addition, you can search Baidu Post Bar for "Prisoner Fitness", which is also suitable for exercises lacking equipment and venues.

Note: persistence will be effective.

Hope to adopt!