In your first warm-up set, you want to do 12 reps with about 50 percent of your heavy, 4- to 6-rep set weight and then rest for 1 minute. This set should feel very light and easy. For instance, if you did 3 sets of 5 reps with 225 pounds on the bench last week, you would start your warm-up with about 110 pounds and do 12 reps, followed by 1 minute of rest.
