Machines Suck!

Way back when, researchers used electrical stimulation on muscles to determine their function. What happens when they stimulated the quadriceps? Knee extension. The hamstrings? Knee flexion. The adductors? Hip adduction. I don't know about you, but I think this is an extremely simple depiction of the human body. What happens every time you take a step? Your glutes, hamstrings, quads, adductors, calves, and the other stabilizers in the lead leg are used in conjunction to decelerate knee flexion. Now what happens in that same leg as it begins to propel itself off the floor? The glutes, hamstrings, quads, adductors, calves, and the remaining stabilizers are used to accelerate knee extension. This is precisely why we shouldn't train muscles in isolation - our bodies simply don't function that way - hence, the term functional training. Now, soon after this research - companies began making machines to simulate the "function" of the different muscle groups. The age of Nautilus machines began.

I'm going to take you through four different machines that suck, for lack of a better word. The leg extension, the leg curl, the hip abduction machine, and the hip adduction machine.

Lets start with what seems like every woman's favorite machine...the inner thigh machine:

The hip adduction machine is used to target the adductors. Take a look at the adductors:


Truth is, the adductors are a complex of five different muscles: the Adductor Brevis, Adductor Magnus, Adductor Longus, the Gracilis, and the Pectineus. Now in the frontal (side to side) plane, all of these muscles are used in hip adduction. However when you start to break things down into real-life functional movements - these muscles all take on a secondary role. The Pectineus and Adductor Brevis are used as hip flexors, while the Adductor Magnus and Longus, and Gracilis are used as hip extensors. When the hip is in a position of flexion (think about hugging your knee to your chest), the adductors are in a greater position to contribute to hip extension. On the other hand, when the hip is in a position of extension (thinking about standing tall and bringing one leg behind you), the adductors are in a greater position to contribute to hip flexion.
Think about a soccer player kicking a ball:

Now take a look at her right leg - its in almost full hip extension. Based on what I just told you, the adductors are now in a position to contribute to hip flexion as well as adduction. The exact motion of the follow through of the corner kick. Now think about a hockey player as they skate:

This hockey players right leg is in a state of flexion. The adductors are now in position to contribute to hip extension in order to push the skate down and propel themselves further down the ice.
The adductors are used in so many different ways, and treating this whole group of muscles as if it only has one single function is both near-sighted and also dangerous. Imbalances could develop within the complex itself and could lead to all sorts of groin injuries.


The hip abduction machine follows the same theme. The main muscle used in hip abduction is the Gluteus Medius. Even though it is a single muscle, it has both anterior and posterior fibers. The anterior fibers are used for internal rotation of the femur, while the posterior fibers are used for external rotation. Again, this machine only focuses on the hip abduction component. Also, when the hips are flexed in this position, it is hard to fire and activate the glutes effectively (think about flexing your arm so that your biceps contract, your triceps on the other side is forced to relax - this is known as reciprocal inhibition).

The leg curl. When you walk, run, sprint, go up stairs - your glutes and hamstrings are used synergistically to produce hip extension. In any real-life setting, the hamstrings NEVER work in isolation of the glutes. Now take a look at the leg curl machine:

Knee flexion and therefore hamstring recruitment, BUT no activation of the glutes. Now lets say leg curls are the only exercise you use to work your posterior chain (glutes, hamstrings, lower back). Instead of training your body to use your glutes and hamstrings synergistically to produce hip extension like in a deadlift - you are training your body to preferentially recruit the hamstrings. Now what happens, when you start running or sprinting? Your glutes are so underdeveloped that the hamstrings now have to work overtime to compensate for the lack of function at the glutes. The end result? A pulled hamstring.

The leg extension machine.

Another machine that makes absolutely no sense. When in life would you ever bring your knee up towards your body and then try to kick your leg out in that position. Unless you're the karate kid, I'm assuming never.

The quadriceps consist of four muscles: the Vastus Medialis, Vastus Lateralis, Vastus Intermedius, and the Rectus Femoris. The Rectus Femoris is also a hip flexor and is commonly tight in most of the American population, because of how much time we spend sitting in a hips flexed position. According to EMG studies of the leg extension exercise, the Rectus Femoris showed improved activity, while in EMG studies of a squat - the Vasti muscles showed more improved activity. Now, the Vasti muscles are much more powerful as knee extensors than the Rectus Femoris and also serve as stabilizers to the knee. So why would we use an exercise that improved activity in an area that is already tight, and also delay activity in a muscle group whose recruitment is imperative for optimal knee health. Also, add in the fact that the ACL is in constant tension, the hip adductors/abductors are not working at all throughout the movement, there is more knee movement, and more joint stress - you're really looking at a pretty dangerous peice of equipment.

With all this being said - no machine is ever going to be able to replace free weights or body weights as a more effective form of exercise. There are a few machines I do use occasionally, but that's for another blog post...

In the meantime,

Train Hard!

Jason