I've seen a few of these threads and had the idea of wheelbarrowing as being a good exercise for backpacking. I don't know and I am not a sports scientist but it seems like wheelbarrowing works on your whole body especially the legs when going uphill. If you have yard work to do anyway maybe it would provide additional motivation for moving the wood pile or remulching the back 40. Any exercise that enhances your physical condition would be better than none.