

解説の山田さんの専門はテニスです。
彼はスポーツ医学が専門だそうです。
サッカーは専門ではないので、よくわかりません。
"せんもん(専門)" is in the lesson "Sport news" (Level 41), along with 11 other useful words. LinDuo has 180 topic lessons like this one, 2,379 words in total. Every word has an illustration, a transcription and pronunciation in a female and a male voice. Just 10–15 minutes a day is enough to learn them all. Free, and works offline.