I've decided to plank 4 times a day as I've been reading how isometric exercises are supposed to be very good for you.
Anyway - I'm not very good! I've built up from 28 seconds to 59 seconds over the past week and aim to get to being able to hold it for 2 mins (I think anything after that is possibly diminishing returns?)
Anyway- what can you do and what's considered decent?