[quoting Quinn's paper] Czikszentmihalyi expands the concept of challenge, indicating that the level of challenge needs to be matched to skills, and should be greater than average.
It is my understanding of the flow theory that challenge needs to be matched to skills. If the performer's skills are below average, the challenge should be average (that is, somewhat beyond the skill of the performer). But if, as you say, the challenge should be matched to skills and should be greater than average, where does this leave our below average performer? Wouldn't the challenge prove to be too difficult and hence cause anxiety and frustration, possibly resulting in abandoning the activity altogether? Similarly when you have a high achiever giving him/her greater than average challenge would be below his/her skills, that would be no challenge at all, but will cause boredom. Neither our hypothetical below average performer, nor the high achiever will experience flow.
Have I misunderstood something in your paper or in Czikszentmihalyi's flow theory?