When planning take-off procedures, you (the pilot) should have a point in mind along the runway in which should the airplane not become airborne that the take-off be immediately aborted. 
As per the Airplane Flying Handbook, if the airplane exhibits a natural tendency to lift off before reaching Vr/Vx (where required), it is generally advisable to lift off and accelerate in ground effect and then climb at Vx as appropriate. This method is preferable rather than forcing the airplane to remain on the ground as this may cause a &quot;wheelbarrowing&quot; effect and will hinder acceleration and overall aircraft performance. 
There is no such thing as a &quot;forced take off&quot;- so don&#039;t let a bad judgment call