Dennis: My back hurts every time I SEE that milk crate! I can split horizontal-like for hours with no break ,but sit me down for 60 seconds in that crate position and I will be in total agony! I guess it's all about whatever is wrong with your spine, mine is multiple herniated discs. I can still do all sorts of wood processing the old fashion way with hand tools, except split a piece of Dennis wood with a wedge and sledge!
Tony, I also have multiple bad discs in both back and neck. Standing in one place is pure Hell for me. Sitting would be a bit more comfortable if higher but sitting low like this does not hurt my back and it gives me great leverage for lifting the logs.