Leg length discrepancy (LLD), one leg being longer than the other, is incredibly common. Several causes can
lead to LLD, such as an injury during childhood that influenced the growth rate
of one leg. Many adults have a leg length discrepancy and don't even know it.
The
average leg length difference in adults is about 1.1 cm and many individuals
are entirely asymptomatic. This is because the other regions of the lower body
compensate for the leg length discrepancy, thus preventing any problem. If,
however, you are struggling with injury and believe LLD might be the cause,
seeing a physician is the best way to get an accurate diagnosis.
Measuring leg length can be complicated. Often using a tape
measure isn't entirely accurate, so getting an X-ray or CT scan is the most
effective way to discover your exact leg length discrepancy.
Despite leg length discrepancy being quite common, there has
not been a ton of research completed on its effect on distance running. There
has, however, been substantial research on LLD in general. One article by Dr. Joseph C. D'Amico, published in Podiatry
Today, gives a great background on how LLD can affect other areas of the
body as well as when and how to treat cases.
The most common ailment suffered by those with a leg length
discrepancy is lower back pain. This is due to the longer leg which puts extra pressure
on the lower back. LLD can also create a plethora of other injuries such as IT
band syndrome, plantar fasciitis or runner's knee.
Since a leg length discrepancy can cause so many issues, it
would seem like anyone with a discrepancy should seek treatment. Researchers
disagree on this, though. Some believe that those with a difference between
1-1.5cm need not do anything if they are asymptomatic.
Others believe that
anyone with a discrepancy over 6mm should attempt to fix that discrepancy
because the LLD could cause a problem down the road. There is no consensus on
who should seek treatment for LLD, but it seems like until further research is
completed, those who do not have symptoms should not worry about LLD.
For those who are struggling with pain due to a leg length
discrepancy, the most common treatment is to put a heel lift in the shoe of
your shorter leg. Another solution that can be used either in addition to a
heel lift or independently is to strengthen weak muscles and improve range of
motion in the lower extremities. Often, muscular imbalances cause by LLD can be
fixed through physical therapy, making it so those with low-level LLD need not
seek further treatment.
Remember, leg length discrepancies are incredibly common.
Many runners worldwide successfully compete despite LLD. If you are struggling
with injury caused by a leg length discrepancy, know that you will get over it
and be back running before you know it!