How can you contend and manage forces coming in from outside when you can't even manage and balance forces within.
It's kind of nice being able to say with a straight face that hammers can help "build" a quality budo body (even if we may not know in our lifetimes exactly how or why that happens).
As for PVC, in Hawaii it's now largely gathering dust while folks address their respective bags of hammers. All in good time. . . .
I'm happy for Meyer Goo, and for those seeking peace of mind regarding what aiki is. While many are busy trying to figure out from afar how and why what you're talking about and sharing works, this Goo guy had the great fortune, then burden, of having taken ukemi from Ueshiba (how many people on this board with an opinion of any stripe can say they know what Ueshiba's aiki felt like first hand?) then going through most of his life lamenting the almost complete lack of those qualities elsewhere in the art to which he's been so long devoted. Through your example and model, I hope Goo Sensei lives to be able to express the aiki that inspired him over half a century ago.
If an aikidoka with a skeptical bent and a genuine scientific pedigree really wants to figure out what makes this stuff tick, really the thing to do is get the training, do the training, revel in and scrutinize the results (as slow coming as they may be), then use that first-hand understanding, ability and self-examination to marshall his/her resources in the research community to do the in-depth analysis using him/her as a guinea pig. As with tum-mo, all of that may not pay off with empirical understanding of the how's and why's after all's said and done, but the data collected along the way in of itself might be worth the effort.
Off to do a shiatsu on the wife, then bring my bag of hammers to bear against some bungee cords. . . .