I don't understand the humor, but let me elaborate:
Kano Jigoro was reportedly about 5'2, and 90 lbs. He used "kuzushi" (off balancing) in his techniques:
“ Usually it had been him that threw me. Now, instead of being thrown, I was throwing him with increasing regularity. I could do this despite the fact that he was of the Kito-ryu school and was especially adept at throwing techniques. This apparently surprised him, and he was quite upset over it for quite a while. What I had done was quite unusual. But it was the result of my study of how to
break the posture of the opponent. It was true that I had been studying the problem for quite some time, together with that of reading the opponent's motion. But it was here that I first tried to apply thoroughly the principle of breaking the opponent's posture before moving in for the throw...
I told Mr. Iikubo about this, explaining that the throw should be applied after one has broken the opponent's posture. Then he said to me: "This is right. I am afraid I have nothing more to teach you."
Soon afterward, I was initiated in the mystery of Kito-ryu jujitsu and received all his books and manuscripts of the school.
”
— Kanō Jigorō, in reporting his discovery
[15]
(
https://en.wikipedia.org/wiki/Kanō_Jigorō)
Wrestling being about athleticism, and strength I would think is self explanatory.
Where is the humor?