Comparison of injury rates between cadets with limb length inequalities and matched control subjects over 1 year of military training and athletic participation. Mil Med. 2006 Jun;171(6):522-5
In clinical practice, it is the normally 60-80 year olds that can no longer compensate for their LLI and present with symptoms. That being said, it is still hard to believe that there was no increase in symptoms. Could it be that athletes break down for multiple reasons, and since LLI was only one of them, they could not see an increase. Tough study to control this one variable. On the clinical side, if you treat a short leg, and the symptoms get better, you are good to go. Rich
Hi Rich,
Actually, it's not that hard to believe there were no symptoms.
In walking, say there is a 20" stride length.
If there was a 1/2" limb length difference that would be the equivalent of walking up or down a slope where there was one foot change in altitude over 40 horizontal feet.
The short leg is not falling that far to have significantly more force on it.
Or is it the long leg that is supposed to have more force because of the little bit of increased vertical acceleration.
With running, the strides are even longer and the relative change in height would be even less.
Eric, the reason you are great in biomechanics is that you think in ways that I don't to get to the solution. Great thoughts. Yes, it is a small force which takes repetitive stress (more seen in runners or cyclists or rowers) or prolonged stress (like in my example of 60-80 year olds) to cause symptoms for sure. The elderly population gets in trouble due to the prolonged compensations more than their actual deformity. Rich