Brighid, earth mother, strength:

Image of stained glass piece by Gail Donovan
From http://www.orderwhitemoon.org/goddess/Brighid.html.

Also from this website, an invocation:

I call upon the strength of the Earth,
The vitality of the Sun,
And the life force within me!

Power flows through my body.

It purges and purifies all that is harmful.
It imbues every cell of my body with radiant health.
Strength and beauty shine through me.

I honor my body.
I shape my body.
I nourish my body with good food and good thoughts.

My mind and body are in harmony,
And I shall be whole and healthy!
So it is, and so shall it be!