Virtual Poster Session

Welcome to the Virtual Poster Session, a new and powerful tool for networking and information exchange. Here you can share your work, search though the poster library, and start a dialogue with others in your field. Each uploaded poster that pertains to force measurement and testing can currently be used to apply for an academic travel scholarship; please see the Scholarships page for application details and deadlines.

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Name: lschroe1

Noncontact ACL injuries occur during movements that involve sudden decelerations and changes in direction due to combined sagittal and frontal plane knee loading. Previous studies have shown altered knee mechanics when decision-making is involved, which may better simulate game-like scenarios in a lab setting. The purpose of this study was to determine how two unanticipated stimuli alter knee biomechanics during a dynamic task. Eight females and eight males, all recreationally-active, participated. Participants completed two unanticipated 45-degree cutting conditions (visual stimulus (VS); human defensive opponent (DO)). For the VS condition, a custom computer program presented one of three visual stimuli in a random order. For the DO condition, a research assistant attempted to “block” the participant’s running path with a defensive move, using the same three random-order tasks as in VS. For both conditions, participants had a reaction time range of 400-500 milliseconds. Separate 2×2 mixed-model repeated measures ANOVAs (condition×sex) were performed, with an alpha level of .05. Results showed a significant condition main effect for knee extension moments, which were greater in DO compared to VS (p=.009). Significant interactions were present for peak knee flexion angles and peak knee adduction moments. Females had greater flexion angles (p=.001) and adduction moments (p=.030) in VS compared to DO. Women had less knee flexion and more adduction moment in VS, possibly suggesting this stimulus amplifies ACL injury risk factors in females. A human defender increased sagittal plane loading in a manner that may better represent loading in game situations.


Name: stevenag

Obesity and female sex are considered independent risk factors for the development of knee osteoarthritis (KOA) which may be due to aberrant gait biomechanics. Few data exist on the interaction of obesity and female sex despite their independent influence on KOA risk. The purpose of this study was to examine the influence of sex and BMI on knee joint sagittal and frontal plane gait mechanics. Dependent variables included the knee flexion moment (KFM) and first peak knee adduction moment (KAM1). Gait biomechanics were assessed in 42 obese and 39 normal weight participants that were matched on age and sex. Kinematic and kinetic data were sampled using a 9-camera Qualisys system and 2 AMTI force-plates. Participants completed walking trials in laboratory standard neutral-cushion footwear at self-selected speed and the external KFM and KAM1 during the first 50% of stance was extracted and normalized to a product of bodyweight (N) and height (m). A 2 (BMI) by 2 (Sex) analysis of co-variance (α=0.05) was used to examine dependent variables with gait speed as a covariate. The BMI by sex interaction was not significant for KFM (p=0.073) or KAM1 (p=0.703). A main effect was observed for sex and females exhibited smaller KFM (p=0.05) and greater KAM1 (p=0.004) compared to males. No differences were found in normalized knee moments between BMI groups. Regardless of BMI, females exhibited aberrant gait mechanics that are indicative of KOA progression. Further studies are needed examining the influence of altered gait in young, healthy females on knee cartilage morphology.


Listed In: Biomechanics, Gait
Name: sgcone

The anterior cruciate ligament (ACL) stabilizes the lower limb against translational and rotational loads while the knee is is multiple postures. Surgical reconstruction, the most common treatment for ACL tears, is intended to replicate the biomechanical function of the native ACL in the postures and activities related to daily living and high-impact activities. In order to improve outcomes from ACL reconstructions in patients in pediatric and adolescent age groups, we need to improve our understanding of the knee posture dependent biomechanical function of the ACL. As such, the objective of this study was to quantify flexion angle dependent changes in the response of the ACL and the total knee to applied loads in the anterior-posterior and varus-valgus directions using a skeletally immature porcine model. To do this, we collected stifle (knee) joints from female Yorkshire-cross pigs at ages ranging from 1.5 to 18 months (n=30 total). The joints were tested using a 6 degree-of-freedom universal force sensing robotic system under applied anterior-posterior loads and varus-valgus moments at 40° and 60° of flexion. Studied parameters included anterior-posterior tibial translation (APTT), varus-valgus rotation (VVR), and anterior force carried by the ACL and its anteromedial and posterolateral bundles. We found increased knee laxity (APTT and VVR) was associated with both younger age and increased knee flexion. Greater anterior force carried in the ACL, and specifically in the anteromedial bundle, was associated with increased flexion, regardless of age. These findings have implications in intraoperative graft assessment and biomechanical models.


Name: Thijs Ackermans

Stair falls are a major problem for older people. The present study: a) applied a novel multivariate approach to characterize the overall stair behaviour while ascending and descending stairs and b) investigated whether the selected stepping behaviour was maintained irrespective of step dimensions. K-means clustering was used to characterize the overall behaviour of 70 older (>65 y) and 25 younger adults based on biomechanically risky and conservative strategies. Age and fall history were not unique factors of the clusters, highlighting the limitations of conventional comparisons. Moreover, changing the staircase to ‘easier’ step dimensions tended to have no effect on the selected stepping behaviour. Further research should implement this multivariate method using a longitudinal approach to identify the behaviours that can differentiate those who will experience a stair fall from those who will not.


Listed In: Biomechanics, Gait