Modification for Pullups

[Addie Wimbrow]

what is a modification for a Pull up...without any weights or equipment?

[Eric Montgomery]

You said no equipment, but I'm assuming you would still have access to a fixed bar somewhere.

Jumping pullups--just don't resist on the negative (downward) portion of the movement unless you want rhabdo or compartment syndrome
Negative pullups--lower yourself slowly from above the bar. Again, don't do too many of them.
Ring rows if you have rings, or you can do pretty much the same thing if you have access to a waist-high bar. Just kick your feet out so your body is at a ~45 degree angle to the ground then pull your chest to the bar. Keep your body tight. Adjust the position of your feet to vary the difficulty level....body closer to horizontal makes them harder, body closer to vertical makes them easier.