Endurance

Begin a consistent program of aerobic conditioning, such as jogging, cycling, cross-country
skiing, stair climbing, elliptical training, etc. A typical regimen to prepare for climbing season
would be to start with three 30-minute sessions/week at low to moderate intensity, gradually
working up to 60 minutes each at moderate to high intensity, while including a 2+ hour
endurance workout at low intensity on the weekend.

Full-body resistance

A program of full-body resistance training to increase strength and balance in the core, legs and
upper body is highly recommended. This is particularly important if you have had any previous
problems with your back, shoulders, knees or hips. Many climbers use yoga and Pilates in
addition to or in place of traditional gym weight training. If you are not experienced at
resistance training, please consult a qualified trainer or instructor to develop a safe program
appropriate for you.

Check the lower back strengthening exercises. 

Conditioning

The best conditioning for alpine climbing is hiking uphill with a loaded backpack. At least twice a
month (working up to every week if possible), do hikes with significant elevation gain. Gradually
increase the amount of weight you carry in your pack, working up to at least your expected
overnight pack weight. Helpful hint: load your pack with jugs of water – one gallon weighs 8
pounds. Great training hikes along I-90 include Tiger Mountain, Rattlesnake Ledges, Mt. Si,
Mailbox Peak, Granite Mountain, Pratt Mountain, and McClellan Butte.

Techniques

Indoor climbing walls like those at Vertical World, and Stone Gardens
provide another type of workout. While indoor climbing is different from alpine climbing, the
footwork and balance techniques you learn will help you with the rock climbing 

Tips on reducing the lactic acid.

Also see Mount Rainier Training Plan here