Presidential Closing Remarks 12:05 PM – 12:15 PM: Immediately Following President's Lectures ROOM: Ballroom 2/3 and Ballroom 1: B-17 Free Communication/Slide – Landing Mechanics: WEDNESDAY, MAY 31, 2006 1:00 PM – 3:00 PM: ROOM 401
Gender differences during landings have been suggested to provide a rationale for the greater number of knee injuries sustained by female athletes. Several studies have reported gender differences in landing mechanics, but no standardized protocol to examine the jump landing has been established. While all jump landings may exhibit some similar characteristics it may be that observed gender differences in lower extremity mechanics vary depending on the type of landing protocol used. PURPOSe: To evaluate gender differences in landing mechanics under two different types of landings.
METHODS: Thirteen male (M) and female (F) varsity intercollegiate soccer players were selected to participate in the study. Kinematic and kinetic data were collected using a Flock of Birds motion analysis system with a Bertec force platform during a jumping task. For the task, individuals jumped off a 20cm platform that was placed half of the subj ect's height from the center of the force platform. Upon landing on the force platform (T1) the subject performed a counter movement jump and was instructed to jump as high as possible and then land on the force platform (T2). The data were processed using Motion Monitor software and custom Lab View programs were developed to identify the variables of interest. Sagittal plane motion (peak (PK) and excursion (EXC)) at the hip (H) and knee (K) were analyzed during the eccentric phase of knee flexion during both periods on the force platform. As well, peak vertical ground reaction force (PVGRF) and time to PVGRF were examined. Gender differences between the two types of landings were analyzed using a mixed factor repeated measures ANOVA.
RESULTS: F demonstrated increased HEXC (43.9 deg vs. 55.8 deg) from T1 to T2 compared to M (40.7 deg vs. 41.7 deg, p = 0.04). However, F demonstrated a smaller decrease in KPK (F= 5.2 deg, M= 12.3 deg, p=0.07) and HPK (F= +0.6 deg, M= 8.4 deg, p=0.09) than M from T1 to T2. Main effects were observed for type of landing for KEXC and PVGRF. T2 was associated with decreased KECX (82.9 v 71.5) but greater PVGRF (2.6 BW v 2.8 BW) than T1. No significant differences were observed for time to PVGRF.
CONCLUSIONS: Males and females utilize different strategies at the hip and knee during different types of landings. These results may shed light on discrepancies in gender-based differences in lower extremity sagittal plane mechanics in recent literature.