Squat on one leg.

One-legged squat is very stable to the knee joint, and many people may not finish it for the first time. It is suggested to start with the simplest squat with bare hands, and then practice one-legged squat after gaining ability.

pull-up

Pull-ups are irreplaceable actions to exercise back muscles. You can also do pull-ups on the door beam, or do pull-ups on the stool with a mop to exercise your back muscles.

stand upside down

Standing upside down against the wall can alleviate the lumbar muscle strain caused by sitting posture. The word can be inverted for 30 seconds, and the longest can't exceed 5 minutes, so as not to suffer from inversion syndrome.

push-up

You can use two chairs instead of parallel bars, put your hands on the chairs to support your body, cross your feet backwards and lift them off the ground, then bend your arms to the limit, and then push your body backwards with your arms until your arms bend slightly, so that you can keep your body as steady as possible during the whole movement and avoid shoulder injuries.