Dumbbells are definitely necessary, and it is best to splice them together. You can do squats, hard pulls and double bends. A pair of dumbbells can exercise almost all muscles. Double-headed bending, double-headed practice. Practice three heads with vertical bending. Find a flat stool to do dumbbell bench press, and the bird will be caught in the chest. You can practice your shoulders. Dumbbells bend over and row to practice their backs. Squat hard pull, leg exercise, core waist and abdomen. It is best to assemble different weights, because different actions use different weights. Dumbbells are really an essential medicine for home fitness.