I think it means that if you are set up, ready to cast, with your rig dangling at the end of your rod, you'll have about 6 to 8 turns of shock leader on the reel spool.
I'd think no more than a few metres or maybe a couple of rod lengths?( depends on how big the retrieve ratio on the reel is I guess)
When I fish Shields pier, I use 24lb main line with enough 35lb line as a leader, to allow about 8 turns onto my reel before starting the lift up the wall.