Salat Positions

The Quran speaks of three positions to be observed during the Salat, they are: Standing, Bowing and Prostrating.

The following verses confirm that the Salat starts in the standing position:

You shall maintain the Salawaat and the Salat Al-Wusta, and stand devoutly obedient before God. 2:238

So the angels called out to him while he was standing, praying in the sanctuary: "God gives you news of John, confirming a Word from God He will be honourable and celibate, as well as a prophet, from among the righteous." 3:39

And if you are among them and you lead the Salat for them, let a group of them stand with you and let them hold on to their weapons. 4:102

After the standing position comes the bowing and prostrating:

We appointed for Abraham the location of the House: "Do not associate anything with Me, and purify My House for those passing by and those standing, bowing, and prostrating." 22:26

Muhammad, the messenger of God, and those with him are stern with the disbelievers and merciful amongst one another. You see them bowing and prostrating, seeking favour from God and consent. 48:29

The Salat ends with prostration:

Then once they have prostrated, let them be positioned behind you and let another group, who has not yet observed the Salat, observe the Salat with you while remaining cautious and while holding on to their weapons. 4:102

The words 'once they have prostrated' indicate clearly that prostration marks the end of the Salat, after which a new group comes to observe their Salat in the place of the first group. There is no mention in 4:102, or anywhere else in the Quran, that the believers should follow prostration by standing once again and repeating the cycle.

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These three Quranic physical movements (standing, bowing and prostrating) are not required during the times of emergencies, fear, and unusual circumstances:

If you fear, then on foot or riding. Then once you are secure, remember God as He taught you what you previously did not know. 2:239

Positions of hands, eyes and head

Various schools of interpretation instruct that the hands must be raised to the sides of the forehead while reciting 'Allahu Akbar'. Others instruct the hands to be wrapped around the waist while standing. Others instruct that the forefinger must point outwards while reciting 'La ilaha Ila Allah' while sitting down after sujood.
None of these movements are found in the Quran, therefore none of them are required by God.