You can invoke an Aspect once per exchange.
You may invoke as many applicable Aspects per exchange as you wish and can pay for.
You may invoke an applicable Aspect as many times during a scene as you wish and can pay for.
Diaspora has a rule called Scope. Some example Scopes are personal, equipment, scene, etc. You may only invoke a single Aspect per Scope per exchange, so it doesn't matter if your character is "strong as an ox" and "has arms like phone poles" because those are both a personal Scope and so only one can be applied to the same exchange.
Of course, Scopes don't apply to Dresden.