Send a video of you swinging a 20 pound warhammer then
Swinging is different but he wasn’t able to LIFT it. I’ll gladly send you a video of me lifting 20 pounds.
Like Tedrius said in your CRT, it was a quote meant to establish just how damn strong Robert was in his prime, that a fairly normal man like Ned was scarcely capable of lifting his weapons. It was likely hyperbolic to a fairly liberal extent, since no man without severe physical impairment, even in his middle age, should be utterly incapable of even barely lifting 20 pounds, even if leverage is against him (so ignore my first reply, kinda dumb retort I admit). It's best to take Ned's actual feats, such as barely managing to keep up with Arthur Dayne for a few seconds, ultra-casually choking out a normal dude like Petyr Baelish with a single hand, and putting up a good fight against a casual Jaime Lannister, as more valid than what is likely a hyperbolic statement meant to assert past Robert Baratheon's near-superhuman strength.