I've developed a severe muscle tear in my tibialis posterior muscle, about midway between calf and ankle. I've stopped running for about 3 weeks now and yet it still seems to hurt quite a bit when I walk or get up from sitting down and it hurts a lot when I go up and down the stairs. It doesn't hurt at all when I cycle so I've been doing a bit of stationary biking but I don't really enjoy it. Do you think using the elliptical or aqua jogging will aggravate the injury?
Are you sure it is a torn muscle? Most muscle injuries are not the severe tears we see in professional contact sports, but of the micro-tear variety. They can be just as painful. In fact, complete tears have been known to be nearly painless, at least for a while.
Has your arch fallen? The Tib. P. pulls up on the arch to maintain its shape and resist pronation. A dysfunctional muscle will allow the arch to collapse, though it may not happen all at once. Use the standing test to insert fingers under the arch to measure for differences between left and right arches.
Sit with your knee bent and position the thumbs of both hands on the rear of the calf just below the protruding Gastroc muscle. The rear calf muscles should be relaxed. Slowly apply pressure in between the Tibia and Fibula at this spot. Fish around for the most sensitive parts of the Tib P. extending from here down to the Achilles. Since the muscle is a supinator, slowly pronate your foot while pinning this muscle with your thumbs, effectively stretching it in place. Do this while dorsiflexing the ankle as well.