The use of anting-anting and orasyon (prayers) is common among older Filipino martial artists, and is, I would say, more prevalent among those who fought frequently in challenge matches or lived in dangerous circumstances. It should be noted that although orasyons are strongly rooted in the Roman Catholic faith, the use of anting-anting includes some cross-over into native, animist religion.
Another point to consider is that anting-anting have no powers in and of themselves but acquire psychological and spiritual significance through practitioner's participation in the rites and rituals of his or her religious faith, wherein the amulet is infused with a personal, spiritual significance. In a similar fashion, the mere words of a prayer do not have any eficacy - it is the intention behind the recitation of the prayer that gives the individual words their significance.
Also consider that orasyon often have specific purposes and that they are frequently used by eskrimadors that are involved in the healing arts. For example, Momoy Canete became well known in the San Nicolas barrio of Cebu City as a healer. Often during Eskrima practice he would pause to treat patients from the neighborhood with spiritual healing and hilot in his courtyard. As he massaged an injury, aligned bones, or healed illness, he recited spiritual words and prayers. Momoy attributed his skill to God and claimed that concentrated prayer developed his ability to heal.
Ultimately the use of anting anting and orayson is not much different than, for example, touching a picture of Jesus attached to the sun visor of your car as you start on a long distance drive - or placing your hand over a St. Christopher medal and saying a prayer as your plane starts to lift off, etc.
Rey Galang has written an article on anting anting that is available through the Bakbakan site:
http://www.bakbakan.com/, and I think there is also information available through a couple of Mark Wiley's books.
Best,
Steve Lamade