1. I am serious about running.
2. I take running very seriously.
3. Running is a serious commitment for me.
4. I am dedicated to running.
5. I am committed to my running routine.
6. I take my running seriously and consistently.
7. Running is not just a hobby for me, it's a serious pursuit.
希望这些句子能帮助你表达你的决心和热情!