It is a hypothesis that if humans fall into the Black Hole, they would be shredded into a million pieces. The highly intensive gravitational force in a black hole could pull and stretch your body parts into microscopic particles.
That depends on into what kind of black hole you decide to jump. If it's an old super massive black hole, it is not impossible, as far as we know, that you may survive. At any case, the effect you are talking about is unbounded tidal deformations.
if you where to see a friend fall into a black hole they would seem like they have stopped moving but in reality they are being pulled into single strands and then completely destroyed. just a fun fact but to answer your question because the gravity is so intense that it pulls you molecules into long strings. Also known as string theory.