Desire such as a person you like.
While exercising such as running or having a race and you need a boost fast. Think in your mind, or making the spell stronger say under your breath
"Heavens of the above, I love (Desire of yours) And I wish of you to let me have faith in myself."
The spell will quickly rub on its effects. If your desire is a person, imagine that the same person is watching you.
It matters on you now to how much stamina has increased.