Yes, indeed, and not only in bodily matters. It is true regarding spiritual strength too, may be even more so.
Only regularity of spiritual activity (whatever it may be – reading books, chanting mantras, meditating or praying) makes us strong in that particular aspect. In whatever area we do exercise, there we develop. So every spiritual activity is an exercise. It is a workout for the soul or the true self.
If we do something only once in a while, sporadically, it will give us the same kind of result. In spiritual activity we try to reach out of material world, and it s not a cheap thing to achieve.
It has very mystical manifestation in the area of spiritually based moral behavior. If a person is always truthful, than he or she acquires the power of speaking the truth. It means that everything said becomes the truth. I think it is a real strength.
If you found this interesting, questionable or inspiring, please, share with your friends or discuss it here in the comments