If you lift heavy, you will can lift both light and heavy. If you lift ONLY light, you will got small and week. The true: you must lift heavy AND light, your body needs stress!
+Eduard Dimitrov please look both at the article and research fully and my response to your comment. Your opinion on this is not supported by scientific research. And the fact that we both agree on the body needing stress to trigger the adaptive response suggests you are responding without reading through it, which is a real shame.