In my high school years , I ignored studying and focused on my club activities .
When I was in high school I ignored my studies and tried hard with club activities.
高校時代は勉強はそっちのけで部活に一生懸命だった
In my high school years , I ignored studying and focused on my club activities .
高校時代 - high school years
そっちのけ - ignore
○○に一生懸命 - focused on ○○/ tried hard with ○○
参考になれば幸いです。