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: cbutowicz

The purpose of this study was to determine differences in core stability between collegiate football players with and without non-traumatic shoulder pain. 20 collegiate football players completed tests of trunk control and muscle capacity. Control was assessed via an unstable chair placed on a force plate. Static control was assessed by center of pressure movement during seated balance using 95% confidence ellipse area (CEA; mm2) and mean velocity (MVEL; mm/s). Dynamic control was assessed during a speed and accuracy target acquisition task. Directional control (DC; mm; COP path to target) and precision control (movement around target prior to acquisition (PC; CEA mm2)) were measured. Capacity was assessed by trunk flexor (FLEX; s) and extensor endurance (EXT; s) and double-leg lowering (DLL; °). MANOVA (Eta) and t-tests (Cohen’s d) assessed group differences (p < 0.05) Core stability was not significantly different between groups. Data presented as mean ± stdev (No Pain/Pain), p-value, effect size: Static control- CEA 183 ± 129/ 131 ± 85 and MVEL 5.7 ± 3.0/6.4 ± 2.6, p = 0.38, Eta =.33; Dynamic Control- DC 49± 9/46 ± 6, p = 0.49, d =.39 and PC 143 ± 72/93± 25, p = 0.051, d = 0.93; Capacity: FLEX 77 ± 38/99 ± 32, EXT 74 ± 22/69± 28, p = 0.22, Eta= .40 and DLLT 14 ± 10/15 ± 11, p = 0.92, d =.05. Our data do not provide evidence of diminished core stability in football players with shoulder pain.

Name: chigh

Previous research has shown the utility of vibrotactile feedback to improve postural sway characteristics in persons with vestibular deficits. Tactile feedback given through vibration has been used more as a modality of training but immediate effects on postural control among older adults have not been investigated.
PURPOSE: To compare the immediate effects of tactile vibration on postural sway in healthy older adults in challenging stance and sensory conditions. METHODS: 10 healthy older adults (76.4 ± 6.8years), performed five standing balance conditions on a AMTI forceplate for 30s each: feet together on firm surface eyes open (C1), eyes closed (C2); feet together on foam surface eyes open (C3), eyes closed (C4), and tandem stance on firm surface eyes open (C5). Participants did 2 trials of each condition both with and without vibrotactile feedback. The feedback was given using a waist belt with sensors that were activated when participants swayed in a particular direction as detected by an Xbox Kinect camera (Sensory Kinetics system; Engineering Acoustics, Casselberry, FL). Center of pressure sway area was compared within each condition using a paired samples t-test to estimate the effect of vibration. RESULTS: See Table 1. Since only 5 subjects could complete C4 data was not included in statistical analysis. CONCLUSION: Tactile vibration did not acutely effect postural sway in challenging stance conditions in healthy older adults. Long term effects of tactile vibration on postural sway in challenging stance conditions need to be investigated.

Listed In: Physical Therapy
Name: stahl22

Purpose: To validate an instrumented figure skating blade that is designed to measure impact forces while skating. Methods: Seven subjects (Age: 21.3±2.8 yrs, Ht: 166.9±2.5 cm, Mass: 64.7±7.9 kg) performed 20 landings each onto artificial ice while landing on the instrumented blade from heights of 17.5cm, 25cm, and 33cm. A custom instrumented blade calibrated to measure in forces in Newtons (N) was used to measure impact forces (1000Hz) during landings. These forces were compared to forces obtained while subjects landed on AMTI force plates located underneath the artificial ice surface. Boot angle (250Hz) and force plate data (1000Hz) were collected using Vicon Nexus. Custom LabVIEW programs were used to determine peak force, loading rate, impulse, and the correlation between the blade force data and the force plate data. Paired T-tests were used to compare peak force, loading rate, and impulse between the blade and force plate data. Alpha = 0.05. Results: Correlations between the blade force data and force plate data were good to excellent: mean r (±SD) = .86 ± 0.08. No significant differences were found for peak force and impulse between the blade and force plate data. Peak force means (±SD) were 1353.7 ± 352.2 N for the blade and 1361.2 ± 309.7 N for the force plate (p=.86). Conclusion: The custom instrumented blade is a valid tool for measuring peak forces and impulse during landings. Current research is focused on increasing the gain of the instrumented blade to improve loading rate accuracy.

Listed In: Biomechanics
Name: bryappie

Footwear plays a significant role in, and can influence children’s gait. Footwear type is especially important as a child grows and develops from a novice to an expert walker. Compared to barefoot walking, children generally have increased spatiotemporal (ST) gait parameters while walking with footwear. Gait variability has also shown to be affected by footwear. The degree of stiffness in footwear could have a large influence on children’s gait and variability. This study investigated effects of footwear stiffness on ST gait parameters and gait variability in novice walkers. Children with an average age of 33.3 ( 7.0) months participated in a single data collection. Heel and toe marker positions were acquired for one minute of walking per condition. Participants walked on the treadmill in three levels of footwear stiffness (rigid: hard-soled stiff shoe, semi-rigid: EVA sole athletic shoe, compliant: moccasin soft-sole shoe) and barefoot. ST gait parameters and gait variability were calculated for each condition using marker. and treadmill forces. ST parameters all increased in the rigid and semi-rigid footwear conditions compared to soft-sole and barefoot. Interestingly, there were no differences between barefoot and wearing a moccasin for any of the ST variables. There were no differences in SD and COV between any of the footwear conditions. The moccasin shoe promotes walking most similar to normal barefoot walking. Standard measures of variability failed to detect differences between footwear conditions. Further investigation into different measurements is necessary to parse out what effect footwear has on children’s gait variability.

Listed In: Biomechanics, Gait
Name: gtierne

Rugby is intrinsically an impact sport which results in concussions being a frequent injury within the game. Repeated concussion is linked to early-onset dementia and depression, and the rules for limiting repeated concussion are an ongoing controversy. Therefore a greater understanding of the dynamics of head impacts in rugby and the mechanism of concussion is required. Accordingly, this study focuses on assessing the use of Model Based Image Matching (MBIM) and multi-camera view video for measuring six degree of freedom head kinematics during an impact event in rugby union. The matching is performed on video evidence using 3-D animation software Poser 4. The surroundings are built in the virtual environment based on the real dimensions of the sport field. A skeleton model is then used to fit the player’s anthropometry for each video frame thus allowing player kinematics to be measured. The results from this initial study suggest that the MBIM method can be applied to head impact cases in rugby union. The head kinematics results from this case are similar to those reported in literature. The MBIM method should be applied to a number of head impact cases to establish thresholds for concussion injuries in rugby. The data gained from the MBIM method can allow for more reliable kinematic data to be inputted into finite element analysis and rigid body simulations of concussion impacts. This can allow multi-axis force measurements to be measured within the brain and neck. This can ultimately lead to an improvement in concussion injury prevention and management.

Name: clachanc

Compliant flooring is a promising intervention for reducing fall-related injuries among long-term care residents but may increase the forces required for direct care staff to perform pushing tasks. We analyzed initial and sustained hand forces required for care staff to push a wheelchair (n=14) or two floor-based lifts (traditional manual and motor-driven) (n=14), loaded with average and ninetieth percentile resident weights, over four flooring systems. Compliant subflooring increased push forces compared to concrete subflooring, especially with vinyl overlay, but pushing over a compliant subfloor with vinyl overlay did not require more force than pushing over a concrete subfloor with carpet overlay. Compared to the traditional lift, the motor-driven lift substantially reduced push forces on all flooring systems. With the motor-driven lift only, resident weight did not influence push forces. These results provide new knowledge about the effects of compliant flooring and motor-driven lifts on push forces in long term care.

Listed In: Other
Name: sunkukwon

Chronic ankle instability (CAI) patients often exhibit altered walking mechanics, due to strength and proprioceptive deficits associated with CAI. Reduced strength and proprioception function may alter walking energetic patterns, by reducing energy absorption and generation capability. It is unclear whether strength and proprioceptive training can affect walking energetics for CAI patients. PURPOSE: To examine the effect of a 6-week ankle and hip rehab program on ankle, knee, and hip joint energetic patterns during walking in CAI patients. METHODS: 15 CAI patients (23 ± 2 yrs, 178 ± 8 cm, 76 ± 9 kg, 83 ± 7% FAAM ADL, 56 ± 10% FAAM Sports, 3.6 ± 1.1 MAII, 4.7 ± 2.0 ankle sprains) performed ankle and hip strength and proprioceptive exercises (i.e., theraband, wobble board, etc.) 3 times per week, for 6 weeks (rehab group). 14 CAI patients (22 ± 2 yrs, 177 ± 9 cm, 75 ± 12 kg, 81 ± 9% FAAM ADL, 56 ± 12% FAAM Sports, 3.4 ± 1.2 MAII, 5.9 ± 3.3 sprains) performed no rehab exercises (control group). We measured ankle, knee, and hip joint power during walking for all patients before and after 6 week duration. Functional statistics (α = 0.05) were used to evaluate the influence of the rehab exercises on joint power for both groups across the entire stance phase of walking. RESULTS: The rehab intervention resulted in up to 0.07 W/kg more positive ankle power (concentric) between 19 and 26% of stance and up to 0.06 W/kg more positive knee power (concentric) between 40 and 48% of stance. No changes were detected in hip joint power during the stance phase of walking. CONCLUSION: Strength and proprioceptive training resulted in an improved gait energetic efficiency via increased ankle and knee power generation during mid-stance. As greater muscular strength can lead to an increase in power absorption and generation, the intervention focusing on strength could be beneficial in improving walking energetics in a CAI population.

Listed In: Biomechanics, Gait
Name: jastein

Mechanography during the vertical jump test allows for evaluation of force-time variables reflecting jump execution, which may enhance screening for functional deficits that reduce physical performance and determining mechanistic causes underlying performance changes. However, utility of jump mechanography for evaluation is limited by scant test-retest reliability data of force-time variables. Purpose: To examine test-retest reliability of jump execution variables assessed from mechanography using two different protocols. Methods: 32 women (mean ± SD: age = 20.8 ± 1.3 yr, height = 167.6 ± 6.3 cm, mass = 68.2 ± 12.7 kg) and 16 men (age = 22.1 ± 1.9 yr, height = 181.5 ± 5.0 cm, mass = 94.1 ± 24.6 kg) attended a familiarization session followed by two testing sessions, all one week apart, during which they performed the vertical jump test and had mechanography data recorded. Participants performed six squat jumps (SJ) per session, with squat depth self-selected for the first three jumps and controlled using a goniometer to 110º knee flexion for the remaining three jumps. Raw data were sampled at 1,000 Hz and filtered with a cutoff frequency of 90.9 Hz using Bertec Digital AcquireTM. Jump execution variables were calculated using a macro program in Microsoft Visual Basic. Eight force-time variables were assessed. Test-retest reliability was quantified as the systematic error (using %difference between jumps), random error (using coefficients of variation), and test-retest correlations (using intraclass correlation coefficients).Results: Jump execution variables demonstrated good reliability, evidenced by very small systematic errors (mean ±95%CI: –1.2 ±2.3%), small random errors (mean ±95%CI: 17.8 ±3.7%), and very strong test-retest correlations (range: 0.73-0.97). Differences in random errors between controlled and self-selected protocols were negligible (mean ±95%CI: 1.3 ±2.3%). Conclusion: Jump execution variables demonstrated good reliability, with no meaningful differences between the controlled and self-selected SJ depth protocols. To simplify testing, a self-selected SJ depth protocol can be used to assess force-time variables with negligible impact on measurement error

Listed In: Biomechanics
Name: asondall

The purpose of the study was to determine whether increasing trunk flexion (TF) and whole body inclination (WBI) angles influences peak knee, hip, and trunk kinematics and kinetics during running. Nineteen participants ran over ground at a self-selected speed under three postures: self-selected normal (SSN), TF, and WBI. Analyses revealed significant differences between conditions for peak knee, hip, and trunk flexion angles and peak knee and hip extension moments. Both TF and WBI postures are effective strategies for reducing peak knee extension moments during running with more load distributed to the hips. This may reduce PFJ stress and therefore aid in knee injury prevention and management. Individual preference of either altered running posture should be utilized in a clinical setting.

Listed In: Biomechanics
Name: lschroe1

Collegiate softball has become increasingly popular since the passage of Title IX. As with any sport, injuries are a common occurrence. Interestingly, the base runner is at the highest risk of injury, and rounding the base, specifically, has resulted in approximately 187 game-day injuries. Rounding the base involves planting the right foot on a raised surface and cutting to the left, a dynamic movement often associated with noncontact ACL injuries. Frontal plane loading and unbalanced quadriceps-to-hamstring co-contraction indices (Q:H CCI) have been associated with increasing the likelihood of noncontact ACL injuries occurring. Neuromuscular abnormalities pre- and post-contact have also been suggested to increase the risk of injury. To date, no study has analyzed the effect of rounding a base on noncontact ACL injury risk factors in softball players. Nine recreationally active females completed two base conditions. The first simulated rounding a base with no base on the force platform (NB), and the second simulated rounding a base with a base on the force platform (WB). Three-dimensional motion capture, one force platform, and electromyography were utilized. Results indicated the WB condition reduced the risk of noncontact ACL injury by decreasing frontal plane loading. Movement patterns at the ankle and abnormal foot strikes may provide a better explanation for why noncontact ACL injuries occur while rounding first base. Post-contact Q:H CCI was significantly greater than pre-contact, indicating significantly greater quadriceps activity post-contact. Neuromuscular training could potentially reduce the load applied to the ACL and decrease the risk of injury.