Tip #1 - Laugh with them not at them
The best way to stop someone loving exercise is to point out their incompetence. Growth means not being good at something for a while before you're good at it. And we build intrinsic motivation (the most powerful kind of motivation) by feeling good at a skill. While they're in this growth phase, keep it light and fun. That will make them want to keep coming back for more.
Tip #2 - 'Do as I do, and as I say'
Try your best to find some form of exercise that is fun for you. If your kids see you having fun, they'll want to make it a part of their daily routine too.
Tip #3 - Challenge what you know about exercise.
Years of conditioning has made most of us believe that exercise is a chore you have to 'get done'. A lot of the time, this is a cultural issue. In other words, it means that the adults in your life probably made it seem like a chore (knowingly or not). In reality, daily exercise can be an absolute blast.
Tip #4 - If you're stuck for ideas, try this video.
It'll spark their imagination and can help your kids learn a whole new way of approaching exercise.