Instead of having a real-life spotter stand behind you to grab the barbell should you falter while doing squats or bench presses, you can use the Smith machine. It has safety hooks that catch the bar should it fall, and it also offers a controlled plane of motion. Advanced users say that's a limitation of the machine because it doesn't require the use of as many stabilizer muscles, but for beginners, the control can be a good thing. To use the Smith machine right, learn how to lock the lowest pin in place and how to unrack it safely.
Basic Functions of the Smith Machine
Look along the vertical columns at the sides of the machine, and you'll see a series of short horizontal bars along the columns, about every 8 inches. Then look at the bar itself. Where the bar meets the vertical column, notice the hooklike pieces resting on the horizontal bars. Smith machines require you to either add round weight plates to the bar, or for a pin-loaded version, to set a pin under the desired amount of weight. Remove the pin altogether to lift no weight. With the bar free of added weight, grasp the bar, roll it away from the horizontal bars it's resting on, and raise up the bar a few inches. Then step away from the bar a bit and let it go. Notice how the springs on the hooks force the hooks to move toward the horizontal bar, allowing the hooks to come to rest back on the bar. This safety feature ensures the bar doesn't fall on you should you drop it.
Setting the Lowest Pin
Smith machines also allow you to adjust the settings so the bar only falls down a certain distance, ensuring the bar doesn't land on your chest when you're doing a bench press, for example. The bar should go as low as your range of motion, but no lower, or you could get hurt. Look along the vertical columns, near the bottom, and locate the metal braces surrounding the column, near the horizontal bars. Each brace should have a pin in it that you can remove, allowing you to slide the braces up or down along the column. To figure out how low to place the two braces for a squat, do a squat and notice how close your shoulders are to the floor in the "down" phase. Set the braces a few inches below the height of your shoulders, double-checking that the two braces are at the same height. For the bench press, set the braces at or below the height of your chest while you're lying on the bench.
Performing a Squat
To do a squat, set the weight bar along the column at the height of your upper chest. Add weight to the bar, or use the pin system to set the amount of weight you want to lift. Err on the light side to start; even though you have a safety feature, you don't want to overdo it and cause injury. For comfort, add a tubular piece of padding to the bar at the center, or wrap a towel around it. Stand facing away from the machine, with your feet under the bar slightly wider than shoulder-width apart. Position your shoulders under the bar, forcing you to bend your knees slightly. Grasp the bar firmly and roll it backward and upward slightly as you stand up. Keep the bar rolled back so it doesn't engage with the horizontal bars. Hinge your hips backward, bend your knees forward, and keep your back straight as you lower down. Stop when your thighs are slightly below parallel to the floor, and then press back to standing. After 10 repetitions -- or when your muscles are fatigued -- roll the bar forward slightly, from the standing position, to place it back on the horizontal bars.
Performing Bench Presses
To use the machine for the bench press, slide the bench so it's perpendicular to the bar, placing the bar so it's a few inches lower than the height of your extended arms while lying on the bench. Add weights to the ends of the bar or set the pins to the desired weight, once again starting on the light side to avoid injury. Lie on the bench with your knees bent and your feet resting on the floor, adjusting the bench so that your upper chest is under the bar. Grasp the bar in a wide overhand grip. Roll your wrists back slightly and press upward, disengaging the bar from the horizontal bars. Lower the bar to your chest and then press it back upward until your arms are straight. After 10 repetitions -- or when your muscles are fatigued -- press the bar upward and then roll your wrists forward to set the bar back on the horizontal bars. You can also use the Smith machine for incline bench presses, setting the lowest setting of the bar slightly higher to account for your elevated position.