>> Stick religiously to a training program. Strains and sprains, often due to poor conditioning, tank many trips. Trail running, especially on hills, combined with leg- and back-strengthening exercises, prepare you the most efficiently. For legs, think squats, hamstring curls, and calf raises.
>> For a good basic regimen, each week do: three to four cardio sessions (with one of these being a long endurance hike with a weighted pack), two strength-training sessions (each separated by at least one day), and one to two rest days. Start this program two to three months before your trip.
>> On any big trek with heavy loads, if you don’t strengthen your back muscles beforehand, you’ll be hunched and hurting. Melanie Pfister, a Pilates instructor in Jackson, Wyoming, prescribes this routine for a strong, ache-free back.