I decided to try
Pavel's Fighter Pullup program to improve my weighted pullups before getting back into SimpleFit. I didn't want to get in over my head, so I started at the "3 rep max" level with the 53lb backpack. Each round of the program lasts five days, with a day rest before starting the next round. I started at day 2 of the first round...
Pavel's Fighter Pullups, 3RM week, day 2, 53lb backpack (5/4/2011)
Set 1: 3 chinups, 1 minute rest
Set 2: 2 pullups, 1 minute rest
Set 3: 1 chinup, 1 minute rest
Set 4: 1 pullup, 1 minute rest
Set 5: 1 neutral grip pullup
If I stick with the program I should be up to around 10 reps with the 53lb backpack in less than two months. I'm not sure if I like the idea of going 5 days at a time without rest though, especially with more than a third of my bodyweight strapped to my back. I'm a little concerned about how the connective tissues will hold up, so I might add in more rest days. I'll play it by ear.