Having developed my dynamism through studying abroad and my physical strength through school club activities, the spirit of cooperation is my strong point.
「Having...」=「Because I have...」
「Having developed my dynamism through studying abroad and my physical strength through school club activities,...」
ポイント：「having developed」は一回だけ使いました。同じ言葉使う場合で、よく２回目をスキップします。
I’m proactive, a team player, and have the stamina to take on challenges. These qualities were developed through studying abroad and participating in club activities.
こんにちは！
ご質問ありがとうございます。
ご質問について、いくつか言い方が考えられますが、例えば、
I’m proactive, a team player, and have the stamina to take on challenges. These qualities were developed through studying abroad and participating in club activities.
とすると、「留学で培った行動力と部活動で培った体力、[協調性](https://eikaiwa.dmm.com/uknow/questions/58868/)が強み。」となります。
役に立ちそうな単語とフレーズ
proactive 自ら行動できる
team player 協調性のある人
stamina 体力
take on challenges 挑戦に立ち向かう
study abroad 留学
club activities 部活動
参考になれば幸いです。
アメリカ合衆国 
日本 
