It appears pilots aren't consulted about the ergonomics of helicopter design. I flew Gazelle in the Army; the seat was absolutely fine for short hops but on long flights, eg UK to Saillagouse, it was agony. Pilots unconsciously lean forward over time due to the slightly curved seat back.
Likewise, thousands of hours in Bell 212s has left me with a weakened coccyx, unable to lift anything heavy.
NEO