Isotonic exercises involve moving your joints and muscles rhythmically and repetitively through their ranges of motion using low resistance, while isometric exercises are static and require you to contract your muscles without joint motion.
Substations are normally outdoors and are enclosed by a wire fence. However in residential or high density areas, the substation may be indoors and housed inside a building to restrict the humming noise of the huge transformers. slide 2 of 6 View of a Substation
In the transmission substation the voltage is increased substantially using step up transformers. The voltage is increased to reduce the transmission losses over long distances. This electricity then is supplied to a power substation where it is stepped down using step down transformers and then supplied to a distribution grid.