Not sure what you're wearing or if you care about concealment but one of the most comfortable holsters for vigorous hiking and climbing I found was a typical crappy padded Uncle Mike's I had for a J-frame. I imagine it would work similarly for running. Not very tactical but was comfortable and protected my body from the gun very nicely. I think it worked well with a J-frame mostly due to the light weight, a model 29 might not work with this idea.
