It is completely normal for a child to hate to practice anything. I remember I used to love to play the piano, but hating having to practice. I think for me personally the reason I hated practice was because I wasn't good at it at that time, you have to practice to get good at anything. But when you are a kid you just don't understand that.
Maybe sports aren't her thing. Maybe you regular sports aren't her thing, maybe you could try golf, music lessons, girl scouts (or Indian Princess). Maybe if she sees you doing an activity that you enjoy that is outdoors maybe she will enjoy it as well. We as moms tend to get so busy that we forget to go outside sometimes and do things! I know I do. Also you can always tell her that if she practices and does her best that she can go to the movies with you, or you will rent a movie with her....
Also, here is another idea, maybe since she is so into movies, let her make her own movie. Let her edit and put the music to it. If this is something she enjoys doing, watching movies, then make her understand what is going on. I'm sure that there are movie making places, but use this as a way to get her to try new things. Tell her that she can do this, if she gives this a try.
Also I would limit her viewing. I know that I am guilty of letting my 3 year old watch tv, more than she should, but sometimes that is all I can do because I have to take care of the other 2, especially my 8 month old, nurse him to bed. Anyway, what I do with my 3 year old is if she starts to give me grief regarding turning the TV off or getting upset because I have said No she can not watch the tv I tell her she will have no more tv for the day if she keeps up with the attitude, and sometimes it ends up that she doesn't get any tv for 2 or 3 days...that only happens on very rare occassions. Just a thought.
One more note, about the training wheels. Sometimes the hardest thing about being a parent is being mean. Take that training wheels off, pad her up, and make her do it. She can refuse all she wants, but as a parent you make the rules and she will have to deal with it. I know that sounds horribly mean, but you know what is best for her, and pushing her to do something you know she will enjoy and is safe is what we are here for. You have to push your kids sometimes. Oh, and are you making her stick with the activities for the whole year/season or do you take her out when she complains that she doesn't like it? Because if you take her out too soon she will never give anything a try and will always end up giving up. Good luck and I hope this helps you a little bit.