Usually to extract juice from vegetable, we throw the vegetable into the blender. So, are there other ways that we can extract juice?
Is it that you don't have access to a blender, or you don't like other effects it has in the process of extracting juice? Pretty much any effective method is going to mangle the vegetables and not leave any better or worse an end product in the de-juiced vegetables.
Assuming it's lack of a blender: If they aren't soft and juicy enough to squeeze out juice, pulverizing them with a meat tenderizing hammer while they're in a freezer-strength baggie (strong enough to prevent vegetable shrapnel from flying all over your kitchen) would probably net you at least a few good gulps.