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Machines vs. Free Weights
Compound Exercise – An exercise in weight training that uses multiple joints. Secondary muscles assist the primary muscles in performing the exercise. Normally, you perform heavier compound exercises prior to isolation exercises. For example, Squats use several muscle groups.
Isolation Exercise – An exercise in weight training that works a single joint. These exercises isolate a single muscle without working other muscle groups. For example, bicep curls only hit the bicep.
Are machines or free weights preferable?
They both have their place in the gym. You should periodically switch between machines and free weights depending on your needs. I have found that experimentation is needed to make appropriate decisions for specific exercises.
Here are some examples that I have found from my own workouts.
I prefer to use compound movements (squats, dead lifts) with free weight barbells or a Smith Machine.
For pressing movements I combine exercises with machine presses and free weights (usually dumbbells).
With machines I can use more weight, and form is easier to perfect since it is guided. Or at the end of a workout when I am fatigued, I will use machines to isolate and burn a muscle. For example, machine curls where I can get a burn and get help to maintain good form.
On some machines this can be beneficial, while with others it might be restrictive and not work well with your bone structure. Take time to properly adjust machines to your height to operate them comfortably. Understand what safety features are available and how to use them before you engage the weights. Free weights, especially dumbbells, often force you to balance in several directions, which require the added use of stabilizing muscles. This is beneficial for an overall good workout.
Variable Resistance Machine - The resistance is variable, which means that the stress (weight resistance) is greater at some points in the movement than others. For example, you can feel the weight more at the bottom of a curl than at the top.
Non-Variable Resistance Machines – The resistance is not variable, which means that they exert equal resistance throughout the movement of an exercise.
Why work with machines?
There are variable resistance machines for isolation (single-joint) exercises that control the path of the exercise. I prefer these machines for finishing a workout with a burn of a muscle. For example, I use a curl machine at the end of my bicep routine to burn out the muscle completely. This routine includes sets that mix 10 to 12 full reps with five reps of partials, and another five reps of negatives or forced reps with the help of a workout partner. At this point in a workout it is no longer important to stimulate stabilizer muscles and it is preferable that the machine guides the path of the weights. Non-variable resistance machines work more muscle than variable resistance machines. Non-variable resistance machines provide more muscle stimulation through an equal amount of resistance throughout the movement.
Variable resistance machines facilitate compound (multi-joint) movements. An example of such a machine is an overhead press machine. More muscles are involved in these exercises. In an overhead press machine the pectorals are the primary muscle worked and the triceps and front deltoids are exercised secondarily. The machine provides the stabilization so you do not use as many muscles. There are two types of variable resistance machines:
Dependent limb motion uses a single structure for performing the movement so you do not have to balance the weight between your left and right limbs (arms or legs). Your body’s left and right side limbs are forced by the machine to lift or press both sides equally. This uses less muscle than an independent limb motion machine, described below.
The independent limb motion (dual axis) machine has independent sides for you to lift. These machines are more challenging than the dependent limb motion machines since they drive you to provide equal force with each limb individually. This type of machine encourages symmetrical strength development.
Why use free weights?
Free weight exercises require greater stabilization by engaging more muscles. They engage more of your core muscles (abs, serratus, obliques, and erector spinae). The disadvantage is the greater risk of injury from loss of control of the weight both during the exercise and from picking up or returning the weights.
Isolation (one-joint) exercises performed with free weights such as barbells or dumbbells can offer more stimulation than a machine that controls the path of the movement. Consequently I prefer to be seated rather than standing for most dumbbell exercises. Sitting stops you from cheating by engaging other muscles to help with the movement, which detracts from the muscles’ isolated use. For example, watch someone executing an exercise with poor form at the gym. You will often see them perform a standing bicep curl, front raises, or side laterals, often bending their knees and springing up or leaning back and using momentum. This is not what they should be doing. They should be keeping the rest of their body as stable as possible. They might not realize how much isolation to the intended muscles they lose, and how much extra risk of injury they face from handling heavier weights than then necessary for the benefit they gain. Try performing a side lateral while seated, which allows you to benefit from the greater isolation. Barbell curls can be performed with your back against the wall, as another example. The more isolation you seek, the more you will want to use machines. This is why I like to use both machines and free weights in various combinations.
Compound (multi-jointed) exercises performed with free weights are the most widely used since they stimulate the greatest variety of muscles. Incline chest presses and seated overhead presses with dumbbells and squats and dead lifts with a barbell all use more stabilization muscles than machines require. Dumbbells generally provide more stimulation than a barbell since they require greater balance between arms.
Are exercises that use your body as the weight good for you?
Yes, exercises such as dips, pushups, lunges, and chins where your body does all the movement are my top recommendations. Cardio exercise with the treadmill, stair stepper, etc. are also examples where your body is the main weight used. This type of exercise delivers the most muscle stimulation possible.