You know, I wonder the same too. Personally, when I pray I just do it where ever I am. I don't do the whole kneeling. When I am at church I just bow my head. It is just a tradition that you don't have to follow. You can pray to God any way you want. Permalink
You dont necessarily have to get on your knees to pray, you dont even have to bow your head and close your eyes...now if your in a Church service, its polite(show respect?) to bow your head and close your eyes during a prayer. You can pray anywhere, it doesnt matter where. Permalink
As others noted, there is no required position to pray. In fact we are told in 1 Thessalonians to 'pray without ceasing' - which would be pretty hard if you had to stay in one position. I often pray while I'm driving, as it is a good chunk of time I spend alone and can talk to God - of course it would be quite dangerous to close my eyes and bow my head.
OTOH, we often do these things because they are a sign of respect and also because they shut out other distractions - if your eyes are closed you are not staring around at other people or whatever while you pray. Permalink