Small grip and stance changes shift which muscles work hardest. Wide-elbow rows hit your upper back, close-elbow rows target your lats. Seated shoulder press lets you go heavier, standing press engages your core more. Supinated bicep curls isolate the biceps, overhand grip works your forearms instead.
When you do a dumbbell row with your elbow out wide, you're gonna work more of your upper back. When you do a dumbbell row with your elbow close to your body, you're gonna work more of the side of your back. When you do a shoulder press sitting down, you're gonna be able to lift heavier weight and work your shoulders more. When you do a shoulder press standing up, you'll lift a bit lighter weight, but you will work your core more. When you do bicep curls with your palms facing up, you're gonna work more of your bicep. And when you do curls with an overhand grip, You're going to work more of your forearm, and when you're doing these side bends, they're pretty much a waste of time and you don't have to do them.
