30 seconds is a long time at GSP speed! One thing I didn't mention is the destructive side if they don't get enough exercise. Obviously it varies from dog to dog, but mine will start chewing on things if he misses one walk. I've never seen a breed with such high energy, not even a Border Collie. He seems to love running just for the sake of running.
Have you ever seen an Irish Setter? Faster than you could believe and completely full of energy that lasts and lasts. Most of their running speed is from 15 to 18 miles per hour and that is a pace they set. Running at full tilt is a question on the speed. 1 of mine passed my wife in the car at 35 miles per hour on a blast of speed after it got loose on her once. Now she does it the easy way and just go outside and opens the car door. Within a few minutes it will be setting in the car waiting for a ride...