My husband has been practicing his golf swing there.
My husband has been working on his golf swing there.
この場合、次のような言い方ができますよ。
ーMy husband has been practicing his golf swing there.
「夫がそこでゴルフのスイングを練習してるの」
to practice one's golf swing「ゴルフスイングの練習をする」
ーMy husband has been working on his golf swing there.
「夫がそこでゴルフスイングに取り組んでるの」
to work on one's golf swing「ゴルフスイングに取り組む」
ご参考まで!