Keeping a young runner motivated

I've been encouraging my elder son (now 11) to run since he was about 7 or 8. His basic aerobic fitness was always q good (probably because Mrs S walked him the 3/4 mile to/from primary school), and 2 years ago was progressing really well.
Last year was a disaster however, as he had Achilles tendinitis (sorted with stretching exercises) & one or two health problems (also now cleared). Earlier this year we also found that he had a tendency to (vigorous) exercise-induced asthma - he now has an inhaler for this.
He's now started at secondary school, whose regime means it's much less convenient to take him to the nearest athletics club in the evenings. On the other hand, the school is v keen on its cross country & athletics, so that seems like the natural replacement.
Unfortunately it seems he's struggled at several of the school X-C sessions so far, apparently due to a regularly recurring stitch. Knowing how he eats, I doubt whether it's due to lunchtime overindulgence, and I wondered if there could be any age-related reason why he might be prone to this.
On the one hand, I'd like to get to the bottom of this and sort it out just to restore his confidence. I'm sure that, once he can run with his peers without worrying about what might next go wrong, the ability he showed in the past will show itself again.
On the negative side, I'm concerned that, with all the setbacks he's had over the last 18 months or so, more negative experiences will put him off running altogether. It's currently his only source of significant exercise (now he gets the bus to school), and he needs some sort of antidote to the PS2/Gameboy/PC games he now seems to play constantly.....

Any thoughts....?

Be gentle with him, Mike! Talented junior runners often burn out early. I have two ex-county-level girl runners on my list, one of whom was also an academic high-flier at junior school, and both had stopped running by the mid-teens and become teenage pregnancy statistics by 18 - so much for running improving self-esteem! And the poor lad has already had a serious overuse injury.

What does he want to do? If he's struggling with XC at school and is dreading sessions, take him out of it. Let him have a rest from running and exercise in a way where he doesn't pressurise himself to perform - swimming, hill-walking, cycling excursions, that sort of thing. If he's a good runner and has you as a role model, he'll get round to wanting to run again.

I've got the opposite - a slightly chunky 11-year-old who wants to be a runner. She's happy enough to potter around at fun runs, but has got her training mapped out for the next 6 years, at which point she intends to do her first half-marathon. We walk and swim together and have the occasional gentle jog or climb a hill, but if I let her have free rein she'd half-kill herself in a week.

Vrap,

Self-esteem was one of the things I had in mind. When he was running well - in particular after he beat a significant number of adults in a fun run 2 years ago - it did wonders for his self esteem.
He has had opportunities to put his name down to run for the school, but hasn't done so - there's the lack of confidence - but maybe that would put him under some pressure to perform, so perhaps its just as well.
Talking to him this evening, his response to his stitch problem seems to be more one of annoyance than despair. We've decided that on his next X-C outing at school, he'll try breathing in and out on his left footstrike rather than his right (which is where he's been getting the stitches) & see if that makes a difference.
We do biking and hill-walking as & when opportunity allows - trouble is, with the nights closing in now, such opportunity tends only to arise at the weekends - once more mundane business (shopping et al) has been sorted.

I agree completely about the difficulty of fitting in family exercise, Mike, especially when you're also trying to make time for your own training. I was quite cross to discover that I couldn't take my daughter to the gym with me in the evenings to have a swim because they don't allow children in after 7pm, and while I'm quite glad that OTHER people's kids aren't milling around there in the evenings, I resent not being able to take Kevin, who is a good swimmer and doesn't mess around. And fitting in time to "train" her for her forthcoming Ben Nevis climb is tricky. We have to go a fair distance to find a decent-sized hill to climb, and weekends are the only opportunity.

I don't have any sporting ambitions for my children, though. All I want is for them to grow up regarding walking as a viable form of transport. Anything else will be a bonus.