Many pastors expect the person they lay hands and pray for to fall backwards. Many worshipers also seem to be attracted to this falling, thinking it's an act of the Holy Spirit though there was no result from this. To me this act does not seemed to be biblical. Please let me know whether I am correct and your views about it.
The practice is typically called being "slain in the Spirit."
God said that He told us everything we need to know concerning life and godliness. "Grace and peace be multiplied to you in the knowledge of God and of Jesus our Lord, as His divine power has given to us all things that pertain to life and godliness, through the knowledge of Him who called us by glory and virtue, by which have been given to us exceedingly great and precious promises, that through these you may be partakers of the divine nature, having escaped the corruption that is in the world through lust" (II Peter 1:2-4).
Understanding this, those who claim that God requires people to fall down first must show that this from the Scriptures. We find evidence of unclean spirits (demons) causing people to fall and lose control of themselves. "Then they brought him to Him. And when he saw Him, immediately the spirit convulsed him, and he fell on the ground and wallowed, foaming at the mouth" (Mark 9:20). But this was not the characteristic of the Holy Spirit coming upon people.
Second, there has to be evidence that every Christian had the Spirit fall upon them. There are records of some receiving the Spirit, but the comments made show that it was a rare event for the Spirit to directly come upon a person. See: Cornelius Received the Holy Spirit.
Third, the Bible shows a consistent patter that the Apostles had the ability to lay hands to bestow the gifts of the Spirit on others but not other Christians. See: Belief, Baptism, and Signs Following – Still Today?
Finally, it would have to be shown that gifts of the Spirit and direct interaction of the Holy Spirit continues today. What we find is that God said that miraculous gifts would come to an end. See: Have Miracles Ceased?