Hi Wycoller
Yes I think you are right, many 16 & 17 yr olds do have the capability to race over 6 miles comfortably, one lad I know has a 33 minute 10k road pb, and distances is something myself & several others are looking at right now. We are getting as much decent research based material as we can in terms of the physiological and psychological demands made upon young runners.
But as you say, we have to take into account that we are seeking to encourage fell running for all juniors as well as testing them. The fact that your daughter was distressed is a classic example getting the balance right between challenging the best runners & encouraging everyone else to stay in the sport through having an enjoyable experince, building strength, capability and capacity over time. There is also often a huge difference between chronological age & biological age as Im sure you know.
Also, if the races distances were extended, a probable side effect would be increased training volumes to compete well at these distances and I know of 5 young runners currently out with some form of Osgood Schlatters. The feedback Ive got from them is training volumes increased were too fast, not allowing decent time for adaptation. Juniors can be very highly motivated and very willing to push hard and please/impress coaches/parents, so again I feel we have to balance the messages about committment & a hard work ethic with a longer term development approach.
But I'm not a physiologist, hence the discussions with various universities, seeking decent appropriate reasearch papers and thinking about the implications of a change beyond the race itself. And of course, distance is but one component of a fell race, the ascent and particularly the loading on young joints of steep, speedy descents is an aspect that hardly applies to a track 3000m or a 5k road race.
However, as I say, I am thinking about race distances and I always welcome thoughts & feedback on anything that will improve the overall experience for all juniors. At the last junior do on the U18 trophy the past winners made intersting reading, not many still running/racing that we could see.
Duncan