How Long Is “Judo Jymnastics”?

In a gym, a girl is pulling some pulleys, to gain arm strength, while three men and three girls watch a judo demonstration in the middle of the room. A girl wearing a sweater and shorts applies a succession of holds to a young man in a sleeveless undershirt and a black trunks: over the shoulder projection, arm lock, over the hip projection, sideways headlock and knee to the face, sacrifice fall followed by school-girl pin, kidney punching followed by a groin kick, sideways kick to the knee and arm-lock, eye-gouge and kick to the ribs, attack to both legs with arms and legs, arm-lock and tripping followed by a leg blow to the throat, disarming a knife attack from above, and then an up-thrust with the knife, disarming a revolver menace from the back, usage of a leather belt to strangle and throw an attacker, usage of hair holds for control and throw of the opponent, and KO punching. The man simulates different forms of attack and stands gamely every time - except the last.