The position of hands in Prayer is definitely not one of the integrals of Prayer, for, according to all scholars, salah is deemed as valid regardless of whether one places the hands above or below the navel or on the chest.
There are different opinions regarding this issue. A Muslim must choose what helps him/her maintain humbleness and concentration in Prayer.
Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states that : It is perfectly acceptable to place your hands either below the navel as the Hanafi School teaches, or above the navel as taught by the Shafi`i School. It is also fine, as some hold, to place the hands on the chest, or even to drop them to the side, as is held by some scholars of the Maliki School.

It is highly important for us to know that the differences among various schools of jurisprudence on this issue are not due to the whimsical rulings or improvisations of the imams or the founders of the various schools themselves; rather they are primarily due to the way they have learned the precise practice and precedents of the Prophet (peace and blessings be upon him) through his own Companions. In other words, these differences are coming from the Companions of the Prophet (peace and blessings be upon him) whose legacy the imams transmitted to their disciples.
This is the only conclusion that we can derive if we study the discussions of authentic scholars belonging to various schools on this issue. For instance, Imam Ibn Al-Humam, a great scholar of the Hanafi School, states, “There is no well attested report from the Prophet (peace and blessings be upon him) obliging us to place our hands either below or above our navels in a definite sense.” Imam Tirmidhi, the author of the great work of Hadith, points out that there are authentic reports from the Companions and their successors indicating that while some of them opted for placing the hands below the navel, others preferred placing them above. Imam Ibn Al-Mundhir also confirms the above statement. There are also reports from Imam Ahmad indicating both views, while he looked unfavorably towards placing the hands on the chest itself rather than below it.