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: catelli

THA is a reliable method to improve the quality of life in osteoarthritis patients. However, it is still unclear whether it would lead to improved functional mobility. The purpose was to develop a biomechanical functional score to quantify the joint mechanics of THA patients compared to healthy participants (CTRL).
Twenty-four THA patients and 12 CTRL (age-, sex-, and BMI-matched) participants were recruited and underwent motion analysis for different ADLs tasks prior and nine months after THA. Three-dimensional joint kinematics and ground reaction forces were collected and five kinematic and six kinetic variables were included in the analysis. The normalized root-mean-square-deviation (nRMSD) was calculated between the THA and the CTRL groups for both pre- and post-op conditions: nRMSD= √((∑_(t=1)^n(x_(1,t)- y_(1,t))^2)/n)⁄(x_max-x_min). Kinematics and kinetics improvement scores (KMIS and KNIS) were calculated to estimate pre/post-op differences: KMIS=∑_(i=1)^n〖〖(KM〗_(pre/ctrl i)-〖KM〗_(post/ctrl i))〗; KNIS=∑_(i=1)^n〖〖(KN〗_(pre/ctrl i)- 〖KN〗_(post/ctrl i))〗.
THA patients experienced post-op improvements, with kinetics variables closely resembling the CTRLs, especially on hip and knee power production. Total improvement scores showed that THA experienced greater improvements during a squat task and this can be a practical approach to evaluate the change in biomechanical function and highlight small improvements that may go unnoticed with traditional statistical analysis.


Name: youngwook.kim

Background: Several risk factors have been identified as contributors to the development of shoulder injuries, including glenohumeral internal rotation deficit, rotator cuff weakness, and shoulder instability. However, lasting deficits of the physical characteristics among overhead athletes with a history of a shoulder injury are unknown. Objective: To compare shoulder range of motion (ROM), strength, and upper-quarter dynamic balance between collegiate overhead athletes with and without a history of a shoulder injury. Methods: 58 overhead athletes were distributed into a shoulder injury history group (n=25) and healthy group (n=33). All participants were fully participating in NCAA Division I baseball, softball, volleyball, or tennis and free of any symptoms of shoulder injuries. An investigator measured active ROM for dominant shoulder internal rotation (IR), external rotation (ER), and horizontal adduction (HAD) using a digital inclinometer. Isometric strength for dominant shoulder IR and ER at 90° of abduction was measured using a hand-held dynamometer. The upper quarter dynamic balance was assessed via the Upper Quarter Y-Balance Test (UQYBT). Results: The injury group demonstrated a lower UQYBT mean score in the superolateral direction. However, there were no statistically significant intergroup differences in shoulder ROM, strength, ER/IR strength ratio, and UQYBT in the medial direction and inferolateral direction. Conclusions: Overhead athletes with a previous history of shoulder injury had poorer UQYBT in the superolateral direction despite a lack of ongoing symptoms or deficits in function. Well-planed dynamic balance training and related strengthening exercises may be warranted for overhead athletes to improve their upper quarter functions.


Name: gtierne

The tackle height law in rugby union has been an area of concern for many years. It is currently set at the line of the ball carrier’s shoulder. The goal of this study is to use Model-Based Image-Matching (MBIM) and human volunteer tackles in a marker-based 3D motion analysis laboratory to examine the severity of a legal tackle to the shoulder/chest of the ball carrier (with no head contact) and the effect of tackles above and below the chest on ball carrier inertial head kinematics, respectively.
From the real-world tackles, the estimated ball carrier peak resultant change in head angular velocity was 30.4 rad/s (23.1 rad/s, 14.0 rad/s and 21.8 rad/s in the coronal, sagittal and transverse direction, respectively). In the staged tackles, the median peak resultant head linear and angular acceleration and change in head angular velocity values for tackles above the chest were greater than for below the chest. The results support the proposition of lowering the current tackle height law. Due to the real-world tackle (MBIM), the ball carrier head kinematics indicated a greater than 75% chance of sustaining a concussion, based on the literature. This was the case even though no contact was made with the ball carrier’s head. Therefore, repeatedly engaging in this type of legal tackle may be detrimental for long-term brain health. However, by lowering the tackle height law to below the chest, ball carrier inertial head kinematics can be reduced significantly, thus reducing the repetitive loading placed on the brain.


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
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: 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: Nicholas_Romanchuk

ACL injury mechanisms are commonly determined from evidence gathered during highly controlled lab-based activities. However, many non-contact ACL ruptures occur following a reaction to an external stimulus, when athletes are unable to pre-plan their movement strategy1. The purpose of this study was to determine if unanticipated drop-jump landing altered lower-limb biomechanics.

Ten participants performed two counter-balanced single-leg drop-jump landing conditions (anticipated and unanticipated). Unanticipated landings were conducted by randomly displaying either a left or right arrow immediately following jump takeoff. The visual cue was triggered by the participant making contact with a force platform, set at a threshold of 10N. Three-dimensional kinematic and kinetic data for the ankle, knee and hip were time-normalized over the jumping and landing phase and with-in participant averaged over the successful trials. Paired sample t-tests, using Statistical Parametric Mapping, evaluated between condition differences over the jumping and landing phases (α = 0.05).
Participants landed with significantly greater hip abduction (p=0.004) during the unanticipated condition over the entire landing phase (0-100%). Participants also landed with significantly less hip external rotation (p=0.048) over the final 17% of the landing phase.

Although no differences were identified at the knee joint, participants landed with greater hip abduction and less external rotation when the movement was unaticipated. Given that proximal factors play a contributing role towards controling knee mechanics, the altered hip position could be a compensatory strategy to limit knee abduction and reduce ACL injury risk during unanticipated tasks2.

1. Olsen et al. AJSM 2004;32(4):1002-1012
2. Powers JOSPT 2010;40(2):42-51


Listed In: Biomechanics
Name: mnvakula

Background: Approximately 33% of the adult population in the United States is considered obese (28), which increases the risk of comorbidities such as osteoarthritis (OA) (34). The most notable feature of OA is the loss of articular cartilage within a joint, resulting in pain and physical disability (3). The association between obesity and OA is due to a combination of mechanical and metabolic factors (3). Greater weight from obesity adds stress to articular cartilage in weight-bearing joints, and contributes to cartilage breakdown (21). Previous studies have demonstrated an association between gait biomechanics and OA in older populations (15, 25), but data are lacking in young obese individuals without OA. Young obese compared to normal weight adults have lesser knee flexion excursion (KFE) (31), and greater vertical loading rates (vLR) during gait (30, 31). However, the source of aberrant gait mechanics in obese adults is unclear, and could be related to impaired shock attenuation from weakened musculature in the lower extremity. Obese young adults have deficits in quadriceps function after normalizing to fat-free mass, and walk slower compared to normal weight young adults. RTD was moderately associated with KEM at habitual gait speed, and KEM was also lesser in obese compared to normal weight adults. The lesser KEM in the obese group suggests that obese young adults walk with a quadriceps avoidance gait, which may contribute to knee OA development. Exercise interventions targeting RTD may be useful for improving walking mechanics in obese adults.


Name: bthakkar

INTRODUCTION:Previous studies have reported that men and women demonstrate distinctly different biomechanics during running and that older runners use a variety of biomechanical adaptations compared with younger runners. It is hypothesized that excessive asymmetry due to biomechanical and anatomical abnormalities contributes to increased risk of injuries, however it is still unclear how age and gender might impact this.METHODS: A cross sectional study was employed and healthy recreational runners were categorized into four groups based on age and gender.Two-way multivariate analysis of variance was performed with age and gender as factors and Symmetry Angle values for peak hip adduction angle (HA), peak knee adduction moment (KAM), peak knee flexion angle (KF), and peak vertical ground reaction force (VGRF) were used as the dependent variables. RESULTS: Overall, gender had a significant effect on HA asymmetry (p=0.02) and both gender and age showed a significant interaction effect on KAM asymmetry (p=0.04).CONCLUSIONS:This study suggests that interlimb asymmetry in running gait for KAM and HA also differs with aging and gender.Understanding age and gender related adaptations in interlimb asymmetry will help improve running performance and develop programs aimed at reducing injury rates.


Name: DKingston

When performing high knee flexion movements (>120º), thigh-calf (TC) and heel-gluteal (HG) structures come into contact and transmit force between segments. Previous work has only assessed the effect of these forces on net external knee joint forces and moments in the sagittal plane. Therefore, the purpose of this study was to quantify the effect of incorporating the 3D location and orientation of TC and HG force vectors on external forces and moments acting on the knee. Sixteen participants (8 M/F) completed five repetitions of six high-flexion movements. Kinematics, kinetics, and pressure distribution (of TC and HG contact) were measured from the right lower limb. Inverse dynamics were calculated with and without TC and HG force, to determine the change in magnitude. During high knee flexion movements, there was a significant reduction in AP forces (~50%) and F/E moments (~27%) as a result of considering contact between lower limb segments. Novel to this study was the ability to account for the 3D force vector and CoF location of TC and HG by tracking the motion of the pressure mat allowing the effect on frontal plane moments to be determined. There was a significant increase in the Ab/Ad moment (~60% in two movements) which is a known risk factor for knee osteoarthritis development. These results will improve the biofidelity of future high flexion musculoskeletal models of the knee. Future work is required to determine if findings from this young and healthy population translates to occupational or individuals that habitually kneel.


Listed In: Biomechanics