The Numbers on The Weights Don't Mean You're Lifting That Much
Keep in mind when you're choosing how much weight to use that you're never moving more load with the goal muscles than the goal muscles can move. For example, imagine doing an arm curl with 25lb super controlled and it's challenging for you vs launching and swinging 50lbs. Your biceps and contributing muscles are still only doing what they can do and the rest of the weight is distributed to other muscles, which were not the intended target. In fact, it's likely you're "cheating" resulted in even less resistance to your goal muscles than the original 25lbs because it's your body's job to make things easy and efficient. Ego lifting only inhibits progress and adds unnecessary risk. Those who measure how strong they are by the numbers they put on a bar or machine often appear very weak when cheating is controlled for. They never gave their muscles a reason to get stronger. Weakness is masked by the skill of cheating, which like anything, you'll get better at if you practice it a lot.