Certain weight lifting machines have been designed to cause the resistance to change during the lift to compensate for the changes in available strength in the muscle throughout the range of motion. Examples are the bench press, leg press and shoulder press machines in our weight room which utilize a lever system to vary the resistance. Nautilus is also variable resistance. It uses a cam shaped like a nautilus shell to vary the resistance during the lift. A type of training in which one applies a strong stretch to the muscle before concentrically contracting.
Examples are hops, bounds, box jumping, and depth jumps.
This type of exercise overloads the muscle by exaggerating the stretch reflex. Thought to develop power. Weight training done rapidly and as forcefully as possible usually utilizing variations of the olympic lifts. Competitive athletes which must develop power most often use these exercises. From the Greek meaning same speed.