for someone to be in good nick requires large muscles and a ripped stomach. The term average nick comes as an insult to a person who really gives it there all in the gym five days a week but just cannot get there muscles big enough or stomach ripped enough to be considered in good nick
Greg - "I've been going to the gym 5 days a week for 6 months"
Richard - "Have you?"
Greg - "yea think its working"
Richard - "em... i suppose your in average nick"