No, the lift was shaky because of the female. (According to my ex-BF.) When I was watching the movie for the first time, with my ex-BF, who used to be a dancer, he said Jennifer Grey's balance & weight was all wrong. There IS an actual technique to a lift. he said she didn't know how to balance herself to make herself "light." The closest I can explain it is: anyone had a small kid that just doesn't want to be picked up and moved, like to go to bed? They make themselves into dead weight and heavy, and suddenly they are hard to move or pick up. Whereas, normally you can lift them right up and play piggy-back with no problems. It's kind of like that. Patrick Swayzee, who was an accomplished dancer, even had a hard time lifting Jennifer up because her balance 7 how she held herself was off. She kind of plopped into his arms.
And there Jennifer was again, and the only advice she could give was "Trust yourself."

And since Derek didn't know how to teach Bindi to balance her weight properly either, the lift ended up heavy & shaky.