Blog Written by: Kathleen White
Reviewed by: Stephen Thomas
The Effects of Neuromuscular Training on the Gait Patterns of ACL-deficient Men and Women
Di Stasi SL, Snyder-Mackler L. Clin Biomech (Bristol, Avon). 2011 Nov 5. [Epub ahead of print] (link to abstract)
After anterior cruciate ligament (ACL) rupture in the US the most common plan of treatment is to undergo reconstruction. Typically, the better the functional level of the patient before surgery, the better the outcome after surgery. Neuromuscular training has been implemented for athletic individuals to prevent ACL injury, to enhance performance, and to improve movement deficiencies throughout rehabilitation. Perturbation (PERT) training is a neuromuscular training program that involves the manipulation of unstable surfaces in both unilateral and bilateral stance positions. It has been implemented prior to ACL reconstruction (ACLR) in an attempt to improve functional status going into surgery [Fitzgerald, 2000]. It has been documented that individuals who receive PERT training before surgery compared to those who received strengthening alone, at 6 months after ACLR demonstrate decreased gait deviations [Hartigan, 2009]. However, these variations have not been evaluated based on gender and have not been examined immediately before and after PERT training. Therefore the purpose of this study was to evaluate gait patterns before and after PERT training in ACL-deficient men and women that are within 7 months of their initial injury. It was hypothesized that men and women would respond differently to the training intervention and this would be observed through gait variables. Gait kinematics and kinetics were recorded with motion capture systems before and after a standard 10 PERT training sessions. Before training, the involved limbs of women demonstrated decreased hip and knee flexion angles and moments at peak knee flexion during gait compared to their own uninvolved limb as well as both limbs of men. Women also demonstrated decreased knee excursions and increased hip excursions compared to men during early stance phase. Prior to training, men only demonstrated knee extensor moment deviations compared to their uninvolved limb. After training, a more symmetrical gait pattern was seen for women between involved and uninvolved limbs. The only deviations that persisted were knee extensor moments between limbs of both men and women.
It is well known that women demonstrate different movement patterns than men that put them at higher risk for ACL injury, which include increased knee valgus angle and increased forces during landing tasks [Hewett, 2000]. This study demonstrated that after ACL injury and before surgery, women move differently than men. This intervention of PERT training also demonstrated the ability to decrease these abnormal gait patterns in women and this symmetrical gait pattern has been found to be maintained at 6 months after surgery compared to those who only received strength training [Hartigan 2009]. Yet the bigger questions still remain. What do these gait deviations mean for our patients? Do fewer gait deviations mean higher function? Improved athletic ability? Lower rate of re-injury? Lower incidence of OA? This study provides continued support for gender differences in athletes with ACL injuries, however we are still unable to predict if these early gait abnormalities influence the long term results of these individuals.