No. The Bible does not command people to assume any particular position in talking with God. On the contrary there are various positions people assume when talking to God. In Scripture we find people praying the following way:

1.Kneeling  

The martyr Stephen knelt as he prayed.  

Then he knelt down and cried out with a loud voice. Lord, do not charge them with this sin (Acts 7:60).  

When Simon Peter brought a woman back from the dead he knelt in prayer.

But Peter put them all out, and knelt down and prayed (Acts 9:40).

2.Standing  

The Scriptures give examples of people praying while standing:

The Pharisee stood and prayed thus with himself (Luke 18:11).

3.Eyes Open   

In the garden of Gethsemane Jesus prayed with his eyes open.

Jesus spoke these words, lifted up His eyes to heaven, and said  (John 17:1).

4.Fall On Face   

In the Garden of Gethsemane Jesus fell upon His face when He prayed.

He went a little farther and fell on His face, and prayed, saying (Matthew 26:39).

 
Summary

Hence we see prayer to God is not so much the position of the body but the right attitude of the heart. The Bible says:

But the LORD said to Samuel, Do not look at his appearance or at the height of his stature, because I have rejected him; for God sees not as man sees, for man looks at the outward appearance, but the LORD looks at the heart (1 Samuel 16:7)