Abs toning

suggy62

Looking for opinions on what people find best for toning their abs.

I'm a 51yo male, 5'9" and down to 193lbs having lost about 45lbs so far. I'm aiming to get to about 180lbs.

Mostly I've been low cal, high cardio & walking (25 - )30 miles per week, sometimes a lot more, but I'd like to get a bit of definition to my abs.

So what do people find most effective for their abs either at home or at the gym?

Thanks in advance