This workout is designed and popular with bodybuilders. This is not recommended because of the high risk of injury. During the concentric phase (as you push the weight up), your spotter will assist you. The spotter when then allow you to lower the weight slowly on your own.
Learn how to increase your gains using cheat training. This technique involves performing a set of exercises to exhaustion, then performing a few more repetitions by breaking good form and allowing momentum and other muscle groups to assist. This not not a recommended form of training. Only experienced individuals should try this.