What gives the power and strenght to the FAITH (mosne'ho-loins)
to support/sustain the INTELLECT (head) that contemplates Hashem's greatness, and the LOVE and FEAR (arms) of Hashem?
( The loins support the upper body).
It's TORAH (SHE'BAAL PEH).
The Torah is the food that nourishes the soul's faith.
AIN OIZ ELO TORAH.
"There is no strength but Torah".
"Girding one's loins" in order to arouse a love and fear of Hashem...
The ideal time for this is during Davening.
Davening is the ideal opportunity to meditate on the Greatness of Hashem and to create within himself a feeling of awe and love of Him.
Concentrate during Davening from the depths of the heart.
(thankyou "lessons in Tanya",
this Sholom Ber Wineberg, he's good.)