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《Gait & posture》2022
BackgroundFalls are common during pregnancy and present potential for injury to the pregnant individual and the baby.Research questionDo center of pressure characteristics during single leg stance differ between participants during and after pregnancy and nulligravida participants in the presence and absence of visual input?MethodsNineteen pregnant participants completed testing during the second trimester, the third trimester, and 4–6 months post-partum. Matched, nulligravida females completed testing once. All participants performed single leg stance on a force platform on each limb for up to 20 s with eyes open and with eyes closed. Center of pressure characteristics were compared between pregnant and nulligravida females using three separate 2 × 2 mixed way ANOVAs, one for each pregnancy time point (second trimester, third trimester, and post-partum) with Bonferroni correction.ResultsPregnant females demonstrated smaller single leg stance time with eyes closed during the third trimester. During the second and third trimester, pregnant participants demonstrated smaller sway and sway velocity across eyes open and eyes closed conditions. During the third trimester and post-partum, pregnant participants demonstrated greater median frequency of the center of pressure data. Pregnant participants also demonstrated smaller sample entropy in the anteroposterior direction during the second and third trimesters and in the mediolateral direction during the second trimester.SignificanceThe decreased total sway and sway velocity observed during pregnancy may reflect rigidity or a protective strategy during single limb stance. Additionally, center of pressure data were less smooth and more repetitive during pregnancy indicating robust differences in postural control strategies and potentially increased fall risk. Because single limb stance is a component of many activities of daily living, the single limb stance task may have clinical utility for testing or training balance in this population with a goal of decreasing falls. 相似文献
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《Gait & posture》2022
BackgroundFoot orthoses (FOs) are used to manage foot pathologies such as plantar fasciopathy. 3D printed custom-made FOs are increasingly being manufactured. Although these 3D-printed FOs look like traditionally heat-moulded FOs, there are few studies comparing FOs made using these two different manufacturing processes.Research questionHow effective are 3D-printed FOs (3D-Print) compared to traditionally-made (Traditional) or no FOs (Control), in changing biomechanical parameters of flat-footed individuals with unilateral plantar fasciopathy?MethodsThirteen participants with unilateral plantar fasciopathy walked with shoes under three conditions: Control, 3D-print, and Traditional. 2 × 3 repeated measures analysis of variance (ANOVAs) with Bonferroni post-hoc tests were used to compare discrete kinematic and kinetic variables between limbs and conditions. Waveform analyses were also conducted using statistical parametric mapping (SPM).ResultsThere was a significant condition main effect for arch height drop (p = 0.01; ηp2 =0.54). There was 0.87 mm (95% CI [−1.84, −0.20]) less arch height drop in 3D-print compared to Traditional. The SPM analyses revealed condition main effects on ankle moment (p < 0.001) and ankle power (p < 0.001). There were significant differences between control condition and both 3D-print and Traditional conditions. For ankle moment and power, there were no differences between 3D-print and Traditional conditions.Significance3D-printed FOs are more effective in reducing arch height drop, whist both FOs lowered ankle plantarflexion moment and power compared to no FOs. The results support the use of 3D-printed FOs as being equally effective as traditionally-made FOs in changing lower limb biomechanics for a population of flat-footed individuals with unilateral plantar fasciopathy. 相似文献
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《Acta orthopaedica et traumatologica turcica》2019,53(6):490-496
ObjectiveThe aim of this study was to compare the biomechanical resistance to rotational and axial forces of a conventional locking nail with a newly designed intramedullary humeral nail developed for humeral shaft fractures with a secure locking mechanism through the distal part of the nail.MethodsInSafeLOCK humeral nail system (group 1, TST, Istanbul, Turkey) and Expert humeral nail system (group 2, DePuy Synthes, Bettlach, Switzerland) of the same size (9 × 300 mm) were examined. In total, 24 fourth-generation humerus sawbones were used in the experiment. Osteotomy was performed at the humerus shaft, and a defect was created by removing 1 cm of bone. After pre-loading 5000 cycles at a frequency of 2 Hz and a force of 50–250 N for axial loading and 5000 torsion torques between 0.5 Nm and 6.5 Nm at a 2 Hz frequency for torsional loading, the failure load values of each load were recorded. Distal interlocking was performed with an endopin in group 1, while a double cortex screw was used in group 2.ResultsAll samples successfully passed the cyclic loading. The initial and final stiffness values were similar between the groups after axial loading (p = 0.873 and p = 0.522, respectively). The mean axial failure load values in groups 1 and 2 were 2627 ± 164 N and 7141 ± 1491 N, respectively. A significant difference was found in the axial failure load values (p = 0.004). Significant differences were observed between the initial and final torsional stiffness between the two groups (p = 0.004 and p = 0.004, respectively). No significant difference was found in the failure load values after torsional loading (11791 ± 2055 N.mm and 16997 ± 5440 N.mm) (p = 0.055).ConclusionThese results provide a biomechanical demonstration of the adequate stability of both nails after axial and rotational loading. The reliability of the newly developed InSafeLOCK humeral nail system, which does not require fluoroscopic control and an additional incision for distal locking, supports its use in the clinic. 相似文献
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《Gait & posture》2019
BackgroundAltered spine kinematics are a common in people with LBP. This may be especially true for populations such as dancers, who are required to perform repetitive movements of the spine, although this remains unclear.Research questionDo dancers with recent LBP display altered spine kinematics compared to their asymptomatic counterparts?MethodsA cross-sectional study of multi-segment spine kinematics was performed. Forty-seven pre-professional and professional female dancers either with LBP in the past two months (n = 26) or no LBP in the past 12 months (n = 21) participated. Range of motion (ROM) during standing side bending, seated rotation, and walking gait were compared.ResultsFemale dancers with LBP displayed reduced upper lumbar transverse plane ROM in seated rotation (Effect Size (ES)= −0.61, 95% Confidence Interval (CI): −1.20, 0.02, p = 0.04), as well as reduced lower lumbar transverse plane ROM (ES=−0.65, 95% CI: −1.24, −0.06, p = 0.03) in gait. However, there was increased lower thoracic transverse plane ROM (ES = 0.62, 95% CI: 0.04, 1.21, p = 0.04) during gait. No differences in the frontal plane were observed.SignificanceAltered transverse plane spine kinematics were evident in dancers with recent LBP for select segments and tasks. This may reflect a protective movement strategy. However, as the effect sizes of observed differences were moderate, and the total number of differences between groups was small, collectively, it seems only subtle differences in spine kinematics differentiate dancers with LBP to dancers without. 相似文献
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《The Knee》2021
BackgroundIt remains unknown how biomechanics change in posterior lateral knee using different fixation techniques in lateral meniscal allograft transplantation (MAT) during simulated toe-touch partial weight-bearing. This study aimed to compare the biomechanical effects on posterior knee between bridge and bone plug fixation in lateral MAT.MethodsIntact knee, bone bridge fixation, and bone plug fixation were tested with 500 N of axial load during knee flexion at 0°, 30°, and 60°, which simulated toe-touch partial weight-bearing. Contact area and peak pressure were assessed on posterior knee and the shift of peak pressure position were measured.ResultsOn the posterior lateral compartment, the contact mechanics of bone bridge fixation were similar to those of the intact knee (all P-values > 0.05), but its peak pressure was higher than that of intact knee at 60° (P = 0.002). For bone plug fixation, the contact area of the posterior lateral knee was significantly lower than those of intact knee and bone bridge fixation at 30° and 60° (all P-values < 0.05). The peak pressure of the posterior lateral knee was higher than that of the intact knee at all flexions and higher than that of bone bridge fixation at 30° and 60° (all P-values < 0.05). The peak pressure position of bone plug fixation shifted more laterally and posteriorly compared with intact knee and bone bridge fixation during knee flexion.ConclusionBone bridges could maintain posterior knee biomechanics better than bone plug fixation during knee bending during partial weight-bearing. 相似文献
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《Journal of Science and Medicine in Sport》2021,24(11):1161-1165
ObjectivesIncreased tibial axial acceleration and reduced shock attenuation are associated with running injuries and are believed to be influenced by surface type. Trail running has increased in popularity and is thought to have softer surface properties than paved surface, but it is unclear if trail surfaces influence tibial acceleration and shock attenuation. The purpose of this study was to investigate peak triaxial and resultant tibial acceleration as well as axial and resultant shock attenuation among dirt, gravel, and paved surfaces.DesignFifteen recreational runners (12 females, 3 males, age = 27.7 ± 9.1 years) ran over dirt, gravel, and paved surfaces in a trail environment while instrumented with triaxial tibial and head accelerometers.MethodsDifferences between tri-planar peak tibial accelerations (braking, propulsion, axial, medial, lateral, and resultant) and shock attenuations (axial and resultant) among surface types were assessed with one-way ANOVAs with Bonferroni post-hoc tests.ResultsNo significant differences were found for tibial accelerations or shock attenuations among surface types (p > 0.05).ConclusionsDirt and gravel trail running surfaces do not have lower tibial accelerations or greater shock attenuation than paved surfaces. While runners are encouraged to enjoy the psychological benefits of trail running, trail surfaces do not appear to reduce loading forces associated with running-related injuries. 相似文献