STRONGLY.
Having ample strength; muscular; powerful.
Forceful; violent; energetic; effective.
Firm; stable.
She says that she doesn't think you are at all strong." – Girls of the Forest by L. T. Meade
That is, if you feel strong enough... – Alias The Lone Wolf by Louis Joseph Vance
My arms are strong enough. – The After House by Mary Roberts Rinehart