strain for effect
To attempt conspicuously and unconvincingly to produce some kind of dramatic or artistic effect, as in a speech, performance, piece of writing, etc. I just felt like she was straining for effect from the beginning of the play right through to the very end. It's so embarrassing reading my old journal entries and seeing how hard I strained for effect back then.
strain for an effect
to work very hard to try to achieve some effect. The actors were straining so hard for an effect that they forgot their lines. Don't strain for effect so much. The authors of this drama knew what they were doing, and it's in the lines already.