I'm weak when it comes to pullups. I've been doing meltdown training and have only been able to knock out a couple of pull ups by the third set. Should I continue doing pullups, or is there another exercise I can substitue?
Try this instead. Place a bench or stool under the pull-up bar. When you can no longer preform pull-ups place your toes on the top of the bench and use your quads to aid on the pull-up. You can use both legs or one leg depending on your strength. Best of Luck.
A slight variation on Older Lifter's good suggestion, as you already have the bar set for squats use that for the pullups and give assistance as required, that way you aren't relying on the chin bar being free and slowing down the workout, which I would hate to happen as having the oppotunity to actually have a slight rest would take away so much of the fun