Which muscles did you strain? If you have strained something that generally means you shouldn't use them (unless it's in a therapeutic/restorative capacity), which is different from "no impact."
For example, if I strain some muscles in my leg I probably should work on stretching and healing and maybe shouldn't try to use them (even in swimming, biking, etc). If I have knee pain, I probably shouldn't do high-impact activity, like running, and can substitute it for biking, swimming, etc.
Giving us an idea of which muscles you strained could help us come up with alternatives. Though, caveat, asking those questions to a physical therapist would be better. As many injuries as I've had and as many times as I've been in PT this is really different from actually being able to give sound advice on the subject