Comparison Of Landing Mechanics During A Drop Jump In Semitendinosus-gracilis Acl-reconstructed Females And Noninjured Females

Abstract

Women with different types of anterior cruciate ligament (ACL) reconstruction have shown similar landing mechanics as non-injured women. ACL reconstruction using the Semitendinosus-gracilis (SG) graft is one of the preferred options for ACL reconstruction in women. PURPOSE: To compare knee valgus between non-injured women and women with SG ACL reconstruction during a 60-cm double-legged drop jump. METHODS: Twenty-nine females 21-35 years of age (non-injured =15, weight: 60.25 ± 10.63 Kg, height: 161.24 ± 6.70 cm; SG = 15, weight: 67.20 ± 11.46 Kg, height: 166.92 ± 8.44 cm) participated in this investigation. Participants performed 5 trials of a double-legged drop jump from a 60-cm height box. The double-legged landing task involved landing from the 60-cm drop box and immediately jumping vertically as high as possible (countermovement jump). Reflective markers were attached over bony prominences of both legs according to the model embedded in the software. A static trial was used to estimate each subject's joint centers. Five infrared cameras (120 Hz) were used to capture the trajectory of reflective markers during the drop jump. Knee valgus was defined as the minimum distance between markers placed at the lateral femoral epicondyles during the ground contact phase. The ground contact phase was defined as the moment of initial contact until the participant cleared both feet from the floor during the maximal vertical jump push-off. The average valgus from five trials was used for analysis using an Analysis of Variance (ANOVA) to compare knee valgus among groups. RESULTS: The ANOVA revealed no statistically significant differences (p= 0.842) between groups for knee valgus during the ground contact phase of the drop jump. CONCLUSION: Young women with SG ACL reconstruction presented similar knee valgus as young women without knee surgery on a 60-cm double-legged drop jump. It appears that young women who undergo ACL reconstruction with SG autograft do not experience long term landing mechanics deficits that could predispose them to re-injury. NIH Grants G12RR03051 and 1P20 RR11126, and NSCA Foundation supported this project.