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!