Futuristic-looking, complex machinery designed to give your muscles the ‘ultimate workout’ is typically less effective than good-old barbells and dumbbells. Using simple free weights (barbells and dumbbells) on basic multi-joint exercises, like the squat, bench press, shoulder press, and deadlift, is still the most effective means of resistance exercise ever invented. Scientific research has shown that many exercise machines lack the proper eccentric component of an exercise that’s necessary to stimulate muscle tissue to grow.