ORIGINAL: psuguru
If the nose is set low then the main gear legs will be inclined backwards, causing the point of contact of the wheels with the ground to be further aft. The other point of view is that the CG will be further forward relative to the mainwheels, so the elevator will have to produce more force to rotate the nose upwards. Really overdoing it will stop the plane rotating at all whereas just a smidegeon will still produce an abrupt take-off.
Actually, the behavior you describe will be caused by the wing actually creating lift in the downward direction because of the negative angle of attack. It would have a little to do about the shift in gear location vs cg location, but it is such a slight change that it is not the main cause of the plane "sticking" to the runway. Even a couple of degrees of negative angle of attack and the airfoil will produce lift towards the ground and you will have a tough time getting it off. However, when you do get rotation, it is followed by the jump in the air because you are probably going very fast and the wing all of a sudden creates a bunch of lift straight up, thus jumping off of the runway.
I designed a high lift plane with a very high lift experimental airfoil, and on the first prototype, the plane was at a slightly negative angle of attack. This was not on purpose, just a construction error and we decided to try it out anyways. It would not leave the runway at all, even after a 300ft roll at full throttle. We then adjusted the landing gear a little and got it to level and the plane took off in 10 feet. Just goes to show that a couple of degrees of angle of attack can make a difference.