I think it is better to exercise outdoors.

Because when we exercise outdoors, There are many activities we can do.

When I was young, l did many do a lot of outdoors activities such as playing tennis, swimming and soccer as all.

-> weight 앞에 소유격을 붙여 사용하시는 경우가 많은데, 잘못된 사용으로 유의하시면 좋겠습니다.

전체적으로 질문에 대한 답변을 잘 해주셨습니다. 수고하셨습니다:)