Medium range exercises are used to gain extra strength and fitness. Usually, heavyweights are used with less number of repetitions. These sort of exercises are mostly the hardest t do. All you need is to have a high level of motivation and stamina, which can be gained by running or cycling.
Positive charge you gave the lines pointing away, negative charge is pointing toward. Don’t have a photo so I can’t fill in the blanks BUT I can tell you the logic