Does performing dumbbell curls on both arms at the same time make a bigger impact than switching off for a rep on each arm?
If you are focused on working your biceps, it does not really matter which method you choose, as long as your form is correct. However, you might find alternating dumbbell curls easier than doing both arms at once. This could be because of a phenomenon called bilateral force deficit, where each arm can lift more weight individually than they can together. The exact reason isn’t fully understood, but it might have something to do with how our nervous system works. It’s not a major issue, but it’s good to keep in mind.
When you alternate between arms, it gives each one a brief break, which might help you squeeze out an extra rep. I usually alternate for that reason and because it allows me to concentrate more on the mind-muscle connection with each arm. It’s tough to fully focus on the stretch and squeeze of the biceps when working both at the same time.
Hope that clarifies things!