Using too much weight is a surefire way to expose yourself to injury and undermine your progress. You see in order to lift a weight that exceeds your current capabilities your body has to find a way to make the exercise easier. There’s a variety of ways your body can do this – from reducing the range of motion and the amount of time under tension to recruiting the assistance of additional muscle’s to help generate more force. One way or another, this simply amounts to doing less work and in this instance, less work means less muscle.
The second problem with using too much weight is that it can cause serious injury. Too much weight and a degradation of form go hand-in-hand and when this occurs, muscle’s can become overloaded in planes of movement they’re weak in. The end result is often ruptures, tears and even dislocations. None of which are exactly ideal. So do yourself a favour. Leave your ego at the door and select a load appropriate to the exercise you’re performing and your levels of strength. This will save you injury, embarrassment and will help you achieve better results in the long run.