When you want to say "I am good at running" in English, you can use the phrase "I excel at running" or "I am skilled at running."

Another common way to express this is "Running is one of my strengths" or "I am a strong runner." These phrases clearly convey your ability in running.

For a more casual tone, you could say "I’m great at running" or "Running is my thing." Choose the expression that best fits your context.