In fact, there is no precise definition of fitness time. The key is to look at the intensity. You can start with the most basic big moves, such as flat bench press, and you can practice chest muscles, deltoid toes and triceps. Basically, you can start practicing from 70% of the maximum recommended weight, and each group is 8 to 12, and the muscle gain effect is the best. Do 3 to 4 groups, rest for half a minute to one minute between each group, and don't rest for too long, which is better for muscle stimulation. Take a rest for 4 to 5 minutes after practicing one action, and then change to the next one. Like the landlord, you are probably a novice. You have been practicing bench press, dumbbell lift and sit-ups from the beginning. It usually takes me about 40 minutes to finish this series of exercises. So the 20 minutes you said may be shorter. Remember to supplement protein and carbohydrates within 20 minutes to 1 half an hour after practice to promote muscle growth, drink some milk, eat some fruits, bread and eggs.

I wish you reach your ideal figure!