Yard work has decent IP benefits, but spear and pole shaking is better.
I think the best stuff comes from solo and then paired training with someone who is developed themselves for a plethera of reasons. Kata is kindergarten level stuff for IP/aiki-which elbow power is an expression of- that will forever be limited due to the limitations of that venue. IME, it actually prevents serious development.
I really just see it as general conditioning right now. Some things have a pole shaking feel to me more than others. For instance, post hole diggers and from this past weekend, swinging a pick axe for hours on end. Definintely different, but similar in some ways. Other things seem to provide different conditioning. Throwing 60lb bags of top soil and gravel on my shoulders and moving them from place to place. You quickly feel how the shoulders can raise/tense to support that load and how the lower back, hips/kua, etc start to tense up and kick in when fatigue sets in. When you relax all that stuff out of the way and just let it pass through you, it's stupidly easy to do and takes very little muscle as we commonly think about it. One of the most interesting things to me was the sensation in the feet and the stability that resulted from keeping that pressure in one part of the foot vs. another. One part I felt extremely stable and connected to the ground and the other my feet felt loose, unstable and disconnected from the rest of me. That particular feeling in the feet is something that I've been thinking about a lot when I train in general, so it stood out to me.