| I remember back in physical therapy school | | | | measurements when they compare the right and |
| the importance of evaluating and treating | | | | left sides of their body. First of all, how |
| people with various problems that were often | | | | much is significant? This question has been |
| directly related to poor posture. We remember | | | | the source of much debate in recent decades. |
| as children hearing from our mothers and | | | | There have been numerous studies in the |
| grandmothers to "sit up straight", or "don't | | | | medical literature that examined the effects |
| slouch". Little did they know that we | | | | of leg length on various structures, most |
| physically could not do what they wanted us | | | | notably in regards to the lower extremities |
| to do. For whatever reason, whether it was | | | | and the low back. Leg length discrepancies |
| tight muscles, weak muscles, crooked spines, | | | | break all of the rules required for healthy |
| long or short legs, we just couldn't do what | | | | joints in the lower extremities and the |
| they wanted us to do. Then over time, these | | | | spine. In response to the asymmetry, muscles |
| minor malformations continued to persist and | | | | will structurally shorten or lengthen to |
| even in some cases worsened as we grew older. | | | | adapt to their new position. (See Figure) |
| | | | |
| The purpose of this article is to provide you | | | | There are two types of leg length |
| with some basic information regarding your | | | | discrepancies that are present. A structural |
| body. Most of you have had minor aches and | | | | leg length discrepancy is the anatomical case |
| pains, while others may have experienced, | | | | in which one bone may be longer or shorter |
| unfortunately, more severe injuries. It's | | | | than the other. A functional leg length |
| easy to understand when we have a fall or | | | | discrepancy refers to the result of something |
| trip and land funny on our knee, or twist our | | | | occurring in your body such as a soft tissue |
| ankle from uneven pavement, but it sure is | | | | contracture or abnormal joint mobility. The |
| quite confusing when we awake one day with | | | | most notable functional leg length |
| that little annoying hip pain. The truth of | | | | discrepancy involves the feet. When we say a |
| the matter is that the surprising hip pain | | | | foot is pronated we mean that it is flat |
| has been developing for quite some time. It | | | | (little to no arch integrity), whereas a |
| just decided to show its ugly head at this | | | | supinated foot refers to a foot that has an |
| point in time. But why am I having this pain | | | | arch. Generally speaking, a pronated foot |
| now? I've never had this pain before. Why all | | | | creates a short leg, and supinated foot |
| of a sudden does my hip hurt? I haven't done | | | | creates a long leg. Of course, during the |
| anything out of the ordinary. The importance | | | | normal gait cycle, there are appropriate |
| lies within the body's own adaptive | | | | amounts of supination and pronation that must |
| potential. | | | | occur in order to achieve efficient and |
| | | | effective ambulation. |
| The basic premise here is that the body | | | | |
| functions as a single unit with many | | | | The most important role is being able to |
| components. Each component influences and is | | | | differentiate between the two. Unfortunately, |
| influenced by other components. Efficient and | | | | differentiating the two can be quite |
| normal motion occurs from the complex | | | | difficult. In most cases, both situations |
| integration of all components. Human movement | | | | occur simultaneously, with one masking the |
| is achieved through the relationships of the | | | | actual degree of the other. Differentiating |
| kinetic chain. The kinetic chain includes all | | | | between the two scenarios requires an |
| bones, muscles and joints of the human body, | | | | extensive evaluation that involves gathering |
| but more specifically the lower half; the | | | | information from several manual tests coupled |
| feet, ankles, legs, knees, hips, pelvis, and | | | | with information gained from weight-bearing |
| low back. This linkage system is made up of | | | | x-ray measurements. Once the proper diagnosis |
| many component parts, each with their own set | | | | has been made, there are various treatment |
| of specifications. These specifications are | | | | options that are available. |
| similar to what you might find for certain | | | | |
| machine parts. In a way, the human body can | | | | When a structural leg length discrepancy is |
| be thought of as a machine. However, unlike a | | | | present by itself, the most logical option to |
| machine that is comprised of right angles and | | | | equalize the leg length is simply by placing |
| nuts & bolts, the human body has the | | | | an appropriate lift under the heel or under |
| capacity to compensate for a malfunctioning | | | | the entire foot itself, depending on the |
| part, and in most cases, in more than one | | | | amount of the discrepancy. Most research |
| area. The human body seeks symmetry. It will | | | | reports more than a 1/4 inch difference is |
| do whatever it takes to achieve that and in | | | | pathological. Some studies suggest that even |
| doing so will compromise tissue health. In | | | | an 1/8 inch difference can be detrimental |
| turn, it will wreak havoc on the proper | | | | especially for the running athlete. Running |
| biomechanics of human movement, which will | | | | causes the ground reaction forces to increase |
| greatly affect performance. The human body is | | | | up to fourfold, as well as, increasing the |
| the "great compensator". It will seek and | | | | metabolic demand. The range of motion of all |
| follow the path of least resistance. | | | | joints increases with greater muscle activity |
| | | | required to control these motions. |
| The goal of any movement should seek the | | | | |
| minimum amount of energy expenditure and | | | | Treatment for the functional leg length |
| maximum joint stability. In human walking, | | | | discrepancy requires the skill of a medical |
| the wide variety of structure and control | | | | professional to address any soft tissue |
| requires complex integrations for an | | | | limitations. These are most notably present |
| efficient motor program. The most observable | | | | in which the pelvis may be tilted or twisted |
| sign of this is a smooth progression of the | | | | in an unusual position. This situation |
| body's center of mass during ambulation. | | | | requires manual therapy techniques to align |
| | | | joints properly and to reduce any unwanted |
| Healthy tissue needs force in order to remain | | | | muscle activity. In addition to aggressive |
| healthy. It requires an optimal amount of | | | | manual techniques, the use of custom foot |
| stress. Too much or too little can be | | | | orthotics may be recommended in either a |
| destructive! Remember we talked about how a | | | | structural or a functional leg length |
| tissue's specifications are similar to those | | | | situation. Asymmetrical foot function may be |
| of a machine? Well, when a tissue's tolerance | | | | causing the leg length discrepancy, therefore |
| to absorb force is exceeded, tissue breakdown | | | | appropriate application of an orthotic device |
| occurs and inflammation and pain follow. When | | | | will either correct or accommodate to the |
| inflammation and pain are present, one's | | | | asymmetry. |
| performance will surely suffer the | | | | |
| consequences. | | | | It should be quite clear that any treatment |
| | | | option chosen must be made only after a |
| One significant condition that impacts | | | | thorough examination has been completed. The |
| healthy tissue is a leg length discrepancy. | | | | examination should include an analysis of |
| Oh, but that's normal isn't it? Everybody has | | | | gait, an assessment of muscle length and |
| one leg longer than the other. Don't they? | | | | strength, joint mobility, and careful |
| Sure, not everybody has exact proportional | | | | evaluation of foot function. |