Er...take them on longer hikes! At their age they can easily do 10 miles! It does take time to work up to it.

But..honestly? Don't worry so much about training. Half of hiking hard miles is upstairs anyways <img src="/forums/images/graemlins/wink.gif" alt="" /> If you can hike miles already, then just getting out for jaunts is all that matters. Training is way overrated IMO.
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