Translation:I like exercising on weekends.
I agree with you that adding furigana would be a good compromise. It would not only look neater, but it would also familiarise learners with the kanji for the word. I hope it's not too difficult to carry out.
As for words using half kanji and half kana, there are actually two expamples that come to my mind. Both 子ども(子供) and 友だち(友達) can be written with just kanji or with mixture of kanji/kana. I've seen both forms of both examples being used. (if this is what you meant and if you are interested)