[Tim Gray]

Thanks, someone elsewhere just pointed the holding back thing too. To clarify for people without the text: many powers allow their target(s) a saving throw to resist, and the difficulty for that is based on the Adept level of the "caster". You can choose to reduce your effective Adept level for a cast, which makes it easier to resist but less likely to fatigue you. This is not mentioned in the section about fatigue from power use.

Yes, there are Feats that muck around with the relationship between various properties of a power, including fatigue.