I think that it’s a major mistake to avoid pulling straps like the plague. You’ll hear reasons like, “It’s not a pure pull” and “You’ll weaken your grip” or “Your forearms will get smaller.” All of these sound convincing, but they don’t hold any water.
Research has discovered (and confirmed for hardcore bodybuilders) that the use of wrist straps offers a significant advantage compared to bare hands for weightlifting. On pull-ups, for example, straps allow subjects to complete an average of one extra rep on all sets performed. Same for dumbbell rows. In fact, straps have been shown to allow lifters to complete an average of two extra reps on all sets attempted. Two more reps than you’d normally be able to do.
What’s better for developing back muscle and strength than being able to complete 1–2 additional reps on every set of your back workout , no matter what your body type or physique goals. When you string those reps together over the course of weeks, months and years, do the math. That’s a lot of work either accomplished or missed, and all those extra reps happen to be those completed at or near muscle failure.
So regardless of what your trainer tells you, always use straps when hitting back. Never let your back development be at the mercy of your grip. If you can do dumbbell rows with 80 pounds for 10 reps without straps, but you choose to do 100-pound rows for 10 reps with straps, not only does your back benefit, but your grip will also be just as strong as before. By adding weight with straps, your grip doesn’t magically get weaker. Now if you want to build a stronger grip, train for grip and forearm strength some other time, just not when it can detract from the goal at hand.