“Isometric alternating bicep curls are a great exercise to build stability in your shoulders, forearms, and biceps,” says Zetlin. To do this while sitting, you’ll need to bring two small dumbbells in your carry-on. “Hold both dumbbells with your palms up at your hip-level and curl one dumbbell upward to your chest,” he says. While doing 12 reps with one dumbbell, you’ll hold the other stationary; then switch for 12 reps on the other side. Do three sets, but “be sure to keep your elbows close to your body with your wrists not falling downward,” he adds.