I cant do barbells exercises.I dont know why.I can grab 55 pound dumbells and do dumbell bench presses with relative ease, but i can't do anything with a barbell even if it's there's like 70 pounds total on it total, I can't do one rep.I can also do 89kg on the chest press machine but I'm siting for that and I can use my legs and back to push.Still I struggle with tiny weights on the barbell.Why?I even see girls at the gym do more.Did I like tear something and that's making it harder? Why doesn't is affect me when I do dumbells?Other exercises dont give me as much trouble.