Walking inclines

Question
HI, I am a 34 yr old female who is about 20 pounds overweight after last child.  My BMI is 27.  In 02' in ran a full marathon and in 07' I ran a half.  Then in Aug 07' I injured my plantar fascia on the rt foot.  I went through all conservative treatments with two PRP injections and finally had the EPF surgery in March.  Through all of this I found out from a geneticist that I have a mild collagen disorder that is attributing to me not healing and my very flat, flexible, no stability feet.  I have been through 3 pair of professional orthotics and am now working with a pedorthist on my fourth pair.  The geneticist said no walking or running, but when she found that I had a vitamin D deficiency, which lead to a bone scan that showed osteopenia in spine and hips, then she said I do need to walk, but have to have good orthotics.  My questions are:  Are there any good tricks with getting orthotics to work besides weaning and constantly letting the pedorthist work with them?  Although it hurts the bottom of my feet, I have been walking a 5 - 8% incline on the treadmill at 2.5-3.0 for about 30 min.  This is kinda hard on my lower back and I am wondering if it is hurting my feet or plantar?  What is a proper routine to ease into hill walking?  I cannot get my heart rate high enough with plain walking because my feet won't allow me to go 4.0.  Is the treadmill okay?  I cannot walk outside because of severe outdoor allergies (I went into anaphylaxis in June of 08, two epipens brought me out) my time outside is limited and I should avoid working out outdoors.  I know it sounds like I should live in a bubble,(it's been a rough couple of years) but I really am very healthy and need to get this weight off.  Thanks for your time.

Answer
I cannot help you with answers about the orthotics for your special problems. But there is a proper way to ease into the hill walking.

I agree that steep hills can stress the back, so you must give yourself time to adapt. The time-honored method for that is interval training with gradual progression. You may have used interval training in preparing for your races.

Here is a sample program. Start your workouts by walking briskly at 1-2% incline for ten minutes as a warm-up. Then increase the grade to 8% for about 2 minutes before returning to 1-2%. After a 2 minute recovery interval, repeat. End your workout with ten minutes of slower walking at 1-2%. If at all possible keep the walking pace constant through these elevation cycles. Start with 4 cycles and add a cycle each week until you reach at least an hour total. If you have time and this is working well for you, you certainly can extend the workout longer than one hour.

The first week of this may seem too easy, but your tendons and ligaments need time to adapt. Hopefully, just sticking to a slow, steady progression should keep the lower back from hurting, while still challenging you. But if it does, don't hesitate to hold back the progression for longer than a week. If need be, you can even reduce the number of intervals you are doing.

You need to hear one final thing. Don't get too wrapped up in a need to have your heart rate at a certain level. I understand your desire to do this, and it would be important for competitive running. But you will still get 90% of the health benefits even without the high heart rates.