First of all, the muscles exercised by practicing arm machine are different from those involved in lifting things in peacetime, so it is not easy to compare them. Arm exercisers mainly practice triceps and pectoral muscles. Lifting things mainly depends on the strength of your hands, waist and abdomen muscles and leg muscles. Secondly, the arm strength device with elastic force of 30KG is mainly shared by the pectoral muscles and the arm muscles, and the sharing ratio will be different according to your posture.