I’ve looked and looked in the starting strength book and I can’t find it or I just missed it. How many sets and reps for the chin up and back extensions am I supposed to be doing?
Starting with 3 sets of pull ups / chin ups is reasonable, and if you’re already hitting high reps (10+) you could consider using weighted chins, although some folks (like me) tend to get elbow pain from doing lots of weighted chins.
We don’t like using back extensions.