What the Rack Pull Is For
A rack pull is a deadlift that starts from pins or blocks instead of the floor, usually with the bar just below the knees. The shorter range of motion lets you handle more weight than your deadlift, which builds the upper back, traps and hip extensors that lock out a heavy pull.
It also gets you comfortable with heavy weight in your hands. Many lifters use rack pulls alongside the deadlift, and some use them to keep pulling heavy through a stretch when a full range deadlift does not suit them.
Set the pins so the bar starts a few inches below your knees, keep your shins close to vertical, and finish tall without leaning back. Sets of 3 to 5 reps tend to carry over well, and pulls from very high pins carry over less.
Log your rack pulls and this page charts your rep PRs and tonnage, ready to compare with your deadlift, so you can see how the two move together.