The short answer is yes. There are many people who, like myself, believe that "ki" is really just about certain bio-mechanical functions, and has nothing to do with mystical energy you channel from the ground or air. The deal with the ground is really about being able to push off of it.
If you get lifted up, as others have said, there are ways to make yourself "heavy" and hard to manipulate. You can also "throw" your weight around to off-balance the attacker. Daito-ryu has a famous "throw" where nage is lifted up by 4-6 people, and then becomes really heavy and knocks them all down. You can see it at about 3:15 in this video
. Lastly, in such a situation, you could also use "ki strength" to help break the grip.
(But don't ask me how, I'm not that far along in my own training.)