The form allows you to perform an exercise correctly and to get the best results from an exercise. It’s best to do less work than to do it incorrectly. The correct form emphasizes three stages in an exercise: concentric, eccentric, and isometric.
The concentric is the explosive part of a lift, while the eccentric is the recoil, and the isometric is the pause portion of the lift. The concentric part of the lift shows the power, and the eccentric portion allows you to keep the muscle under constant tension as the isometric portion helps you reset and control the weight.
The more difficult an exercise becomes, the quicker form breaks down. By not abandoning the correct technique during an exercise you get the best result. Also, it is important to remember that the right technique allows you to work the muscles intended.