Abstract
The purpose of this study was to compare joint couplingpatterns and variability of the rearfoot and tibia during running subjects who were treated with two types of orthotic devices to that of controls.  Eleven subjects with various lower extremity injuries were treated unsuccessfully with a standard orthotic, and then successfully with an inverted orthotic. Three-dimensional kinematic data were collected while subjects ran without orthoses and then in standard and inverted orthoses.  Eleven healthy subjects ran without orthoses for comparison.  The rearfoot inversion/eversion and tibial internal/external rotation joint coupling pattern and variability relationship was assessed using a vector coding technique. It was hypothesized that when the treated runners ran without orthotic devices, they would exhibit lower joint coupling ang les and lower joint coupling variability compared to the controls.  In addition, it was hypothesized that there would be no difference in the coupling angle or coupling variability between the standard and no orthotic conditions of the treated runners.  Finally, it was hypothesized that couplingang angle would decrease and variability would increase in the inverted versus the standard and non-orthotic conditions.  No significant differences in joint coupling patternor variability were observed between the treated and control subjects. In addition, no significant differences were noted between theorthotic conditions in the treated group. These results suggest that foot orthotic devices do not produce significant changes inrearfoot–tibial coupling. Therefore, the relief experienced with the inverted orthotic is likely due to factors other than alterations in this coupling.

The importance of core stability to prevent and treat running injuries ore stability training is gaining popularity in the running community as more runners are madeaware of how weakness in the “core” of the body can negatively influence lower extremity iomechanics and running performance.  The lumbar, pelvis and hip region together areconsidered to be the core of the body and optimal core function involves both mobility and tability.  When the core is functioning efficiently, advantageous length-tension relationships aremaintained which allow the runner to produce strong movements in the extremities. More mportantly, proper core stability can help maximize running performance, maintain the center ofgravity over the base of support, control lower extremity limb motion while running, and help revent running-related injuries.

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Abstract

Objective:

To determine bilateral lower extremity joint accommodations during gait in anterior cruciate ligament deficient subjects and uninjured controls.Design. Gait testing of 10 chronic anterior cruciate ligament deficient subjects prior to and 3 months following reconstructive surgery, and 10 uninjured controls.

Background:

It is possible that bilateral joint accommodations could occur as a result of anterior cruciate ligament injury and in response to surgical repair.  Few studies have investigated bilateral joint accommodations to anterior cruciate ligament injury andthere is little consistency in the reported results.

Methods:

Bilateral lower extremity kinematic and kinetic data were collected from 12 walking trials and inverse dynamics calculationswere made to estimate bilateral knee and hip joint angle, moment, and power patterns during the stance phase of gait.

Results:

Control subjects exhibited asymmetrical hip but symmetrical knee joint moment and power patterns.  In contrast, theanterior cruciate ligament deficient subjects exhibited symmetrical hip and asymmetrical knee joint moment and power patternsprior to and following reconstructive surgery.

Conclusions:

Gait asymmetry in healthy subjects should not be considered pathological.  In addition, chronic anterior cruciateligament injury results in joint specific, bilateral lower extremity accommodations in gait mechanics.  These accommodations persist3 months following surgical repair.