Studying with reversed flashcards

I use my Anki decks both ways at the same time, and it seems to work for me. I find it harder to remember the Spanish words so English to Spanish is harder, but mixing them up seems to reinforce the meaning both ways. I have also found that using verbs in context is much more effective than just the infinitive -

Están nadando en la piscina

Good luck with your learning!

Personally, I think using your deck in the forwards direction is more effective for your listening and reading skills. You can see or hear the word nadar and quickly think of to swim, which improves your comprehension.

However, if you are in a conversation where you need to use your Spanish speaking skills, it is likely that the English word to swim will come to mind before the Spanish word. So if you use your flashcards in reverse, when you think to swim in that conversation, you'll find it easier to remember the word nadar than if you had only used your cards in that one direction. In this case, it is unhelpful to think nadar and then see a picture of a swimmer, because in real life, you are probably more likely to see a swimmer and have to think nadar.

Of course, there's probably no point studying them at the same time. Study it in one direction one day, and then the other direction the next, and it will even count as an additional review for you!