How to introduce resistance into Wii Fit exercises

Wii Fit suggests that for certain strength-training exercises, you might want to introduce resistance once you've gotten used to the exercise.

Problem: it's hard to hold a weight/waterbottle/whatever in your hand while you're holding the Wii controller in your hand, and it won't count your reps if you don't have the controller in your hand. And holding both the controller and the weight in the same hand makes it difficult to maintain your grip on the weight, which is a wee bit unsafe.

Solution: use an elastic to strap the controller to the weight. Hold the weight and do the reps normally. This way the Wii controller will still count the reps, but you don't have to wrap your hand around a controller AND a weight.