Channelling Reiki into your body is a very simple non invasive way of quite literally giving you an energy boost.

You do not have to understand how or why to accept it.

Channelled reiki into your body will locally  affect the magnetic field and therefore create a change in the flow of charged particles in the area.  For example allowing positively charged Calcium ions to migrate into the painful area and start the healing process to sore muscles.

Its all about helping your body to find its equilibrium and heal itself, generally the higher your energy the better you feel so why not go for it?