If you’ve been working your arms like crazy lately but aren’t seeing any changes in your muscles yet, a tiny, effortless, tweak in your form could make all the difference. According to one expert, your hands (and what you do with them!) are the key to that sculpted look.

“Your grip is one of your body’s three main power sources, behind your glutes and core,” Karen Smith, Dallas-based trainer and master kettlebell instructor, told Women’s Health. “When you can grasp a weight more securely, you transfer more energy to your muscles so they can handle more time under tension, carry heavier loads, and even produce more reps.”

“When you can grasp a weight more securely, you transfer more energy to your muscles so they can handle more time under tension, carry heavier loads, and even produce more reps.” —Karen Smith, trainer

By improving your grip—and squeezing your dumbbells instead of holding them loosely during your workout—you could totally bridge the difference between crushing your reps and crushing your reps with toned biceps. Those hard-to-open jars in your pantry won’t even stand a chance.

This is the intense arm workout Ashley Graham swears by. Or, work your arms and abs at the same time with this five-minute routine.