My understanding of "a circle without meat" is that your waist and abdomen don't have much subcutaneous fat. I don't know if this understanding is correct.

If you train to improve your basketball ability, you should focus on training thigh muscles (quadriceps femoris) and calf muscles (gastrocnemius and soleus). And in order to improve the stability of your aerial posture, you should also exercise your abdominal muscles (rectus abdominis, oblique abdominis).

Training plan.

Standard squat: facing the wall, feet apart slightly wider than shoulders, toes against the wall. Put your hands on the wall and look up as far as you can. Then squat down and ask your knees not to touch the wall, and your thighs and calves are at 90 degrees. Get up.

Number of groups: 4 groups

Group interval: 1 min

Number of each group: 60% of the limit number you can do this action at a time.

Frequency: three times a week, training every other day.

Load-bearing heel: You can make your own load-bearing bag with schoolbags and bulky reference books.

See the picture above for the action. The number of groups, interval between groups, frequency and times of each group are the same as those of squat.

Abdominal muscles: It is suggested that you can follow abdominal muscle training's video for 8 minutes every day. Abdominal muscle training is much more comprehensive than sit-ups, with little risk and no easy injury to cervical and lumbar vertebrae. Do it once a day. You can slow down, but the movements must be standard.