Efficiency is a word that refers to the ability to do something without wasting any resources, whether these resources are time, money, or materials. If you are efficient in your household budget then you will not waste time or money on anything that is not essential. Efficiency of movement means not wasting any energy, instead you will use as few movements as possible to accomplish what you are trying to do and reserve energy for other things.
Real difficulties can be overcome; it is only the imaginary ones that are unconquerable.