Why are you still at zero pull-ups?
You have been hanging from a bar for weeks. Maybe months. You pull. Your chin refuses to clear the bar. You drop back down and feel like your body is betraying you. It is not. The program is betraying you.
The standard advice is brutally incomplete. Jump up, do negatives, repeat. That skips three layers of foundational strength that need to exist before a negative rep does anything useful for you.
A pull-up is a full-body tension event. Your lats initiate. Your biceps assist. Your core prevents your hips from swinging out and stealing the load. Your scapulae depress and retract before your elbows bend even one degree. If any of those links is missing, the chain breaks. You hang there. You feel weak. You are not weak. You are just untrained in the right sequence.
Most gym-goers also confuse a chin-up with a pull-up and treat them as the same movement. They are not. A chin-up uses a supinated grip and loads the biceps heavily. A pull-up uses a pronated grip and forces the lats to carry far more of the work. Both are legitimate. Treating them as identical skips important mechanics.
The other overlooked cause is grip. People with weak grip strength fatigue their forearms before their lats ever get a real training stimulus. Your lats might be completely capable of pulling, but if your hands open at rep three, the set ends at rep three and your lats learn nothing.
Common misconception: lat pulldowns directly transfer to pull-ups. They do not, not one-to-one. A machine keeps the load path consistent and eliminates the need to stabilise the scapula actively. A bar demands scapular control the machine was never teaching you. Use lat pulldowns as a supplement, not a substitute.
The fix is staged. You address scapular strength first, grip endurance second, and only then introduce partial and full range work. Skip the staging and you will be at zero for another six months.