Dr. Corenman, I have a question about exercise to promote bone growth of a lumbar fusion. I walked the first three months of recovery, now that I’ve resumed cycling 2-3 hours daily I’m thinking about discontinuing walking. Does the weight bearing aspect of walking promote more growth than cycling? I stand at least 30 min. of the cycling workout would this be sufficient or should I continue with the walking. Thanks for your advice on this topic.