That Damn Outer Thigh - by Melissa Gissubel

Almost all gyms have an “outer thigh machine” (see figure 1 below).  It’s the machine in which you place yourself in a seated position and then press the outer thigh outward against pads.  The machine illustrates with words and pictures that it works the “outer thigh muscle” and therefore, one would assume that by doing this, the thighs are getting a good workout and will therefore become toned. 
 

Problem is, there is no “outer thigh muscle”. 
 

This means, among other things, not only is the exercise not working, it’s probably setting you up for injury.
 

 The muscle that is primarily responsible for moving your leg outward to the side away from your body (abduction) is the gluteus medius.  This is where the true issue lies: That particular muscle doesn’t even function in that capacity when your hip is in a seated position. The seated abduction machine does not work the hip abductors because the hip (femur) is in a flexed position. There has been biomechanical analysis that has provided evidence that the seated abduction machine places improper forces on the hip joint and cartilage and, in time, may lead to deterioration of the joint’s surface and creating restriction from chronic isolation based training is a common precedent to dysfunction, pain and injury. 
 

In fact, research shows that in the seated position, the piriformis and the tensor fasciae latae (2 very small muscles of the hip) are being loaded and the gluteus medius and minimus are in a poor position to abduct the hip (1).  The glute medius and minimus along with the gluteus maximus are the muscles that need to be toned and conditioned to address the saddlebag problem of which most people complain, and of which the machine purports to address. Muscle fiber alignment as it relates to the direction of resistance will ultimately dictate which muscles are used.  When the hips are flexed, the muscle fiber alignment of the glute medius (as well as the glute minimus) no longer matches the direction of resistance. Hence, it is in a poor position to abduct the hip.
 

So if those muscles aren’t being worked, just what muscles are we really training here?  According to the operational diagrams pictured on the machine, it is the abductor “muscle” that runs down the outside of the leg that is getting a work out. I find this particularly strange because there are absolutely NO abductor muscle(s) that run laterally down the leg. The “muscle” pictured is actually the ITB (Iliotibial Band), a tendon that is the continuation of the tensor fasciae latae. 
           
As a result, the “outer thigh” machine may be more of a risk then a benefit. Because the IT band gets overworked and shortened in this position, the body has to compensate and override the imbalances that are happening. The next thing that occurs is low back dysfunction as a result of an anterior pelvic tilt that forms (caused by tight low back extensors, tensor fascia latae, hip flexors, and weakened gluteal muscles). Your body works as a kinetic chain and if one muscle is tight then the other muscles have to pick up the slack.  Many postural problems such as externally rotated feet (a.k.a walking like a duck) and hyperlordosis (exaggerated lumbar curve in the spine) can be created.   

Figure 1 - uuugghhh….
 

We already know that as a societal whole, we all sit down too much - now adding resistance in the same position and moving our legs out to the side is going to make us better?  Stand up and grab some dumb bells or tubing to make the exercise more functional, safe, and effective.
 
References:
 
1. Hittner, Noah.  (2003). Avoiding the Traditional Pitfalls of Training.(www.ptonthenet.com)
 

About the author: Melissa Gissubel