pack riding(n = noun.act) - riding with a pack;
is a kind of horseback riding, riding

back pack, blister pack, bubble pack, butt pack, cross-country riding, disc pack, disk pack, endurance riding, face pack, fanny pack, horseback riding, ice pack, little red riding hood, pack, pack animal, pack away, pack horse, pack ice, pack in, pack of cards, pack of troubles, pack off, pack on, pack rat, pack saddle, pack tent, pack thread, pack together, power pack, riding, riding bitt, riding boot, riding breeches, riding crop, riding habit, riding horse, riding lamp, riding light, riding master, riding mower, riding school, six pack, trail riding, waist pack, wolf pack