Rugby player

Athlete

Rugby player link (Athlete)
Not typically a sport full of dissidents

A Rugby player can play either professionally or as an amateur, in the several different leagues of the sport, which are traditionally popular in the old British empire countries.

It does imply a rugged physique (when young at least), suited for the military. It is not typically a sport full of dissidents, but instead might point to belonging to "old boys network".