Effects of Footwear on Deadlift Performance between a Hex Bar and Traditional Bar

The conventional deadlift is mainly performed using a straight (traditional) bar, however variations of the deadlift can use other types of bar such as the hexagonal (hex) bar which shifts the loading to a lateral position on the body. Despite the limited research available, training barefoot has become an uprising training modality that anecdotally suggests improved performance. PURPOSE: To observe the performance differences between a hex bar deadlift (HEX) and the traditional bar deadlift (TRAD) in barefoot and shod conditions. METHODS: On day one, one-repetition maximums (1RM) were assessed for thirteen resistance-trained male and female subjects in only the TRAD condition. At least 72hr later, subjects performed five repetitions in four different conditions (barefoot and shod for both HEX and TRAD) at 70% 1RM. A 2 x 2 (footwear x bar) ANOVA was used to assess differences in barbell vertical displacement (DISP), peak vertical velocity (PV), peak vertical ground reaction force (VGRF), total mechanical work (WORK), and lift time (TIME) during the concentric phase. RESULTS: It was observed that there was no significant interaction between the footwear and bar conditions (p\u3e0.05), however there were significant main effects within the footwear condition (p \u3c 0.001) and the bar condition (p = 0.024). The shod condition was observed to have significantly greater DISP (0.522m vs 0.491m) and WORK (473.5J vs 451.9J) compared to the barefoot condition. The HEX condition was observed to have significantly greater PV (0.847m/s vs 0.784m/s) and WORK (474.0J vs 451.3J) compared to the TRAD condition. CONCLUSION: Despite contrary belief, this study suggests that there is no improvement in deadlift performance when lifting barefoot compared to lifting with shoes. However, the shoe does provide an increase in DISP and WORK performed during the deadlift, which implies an increase in the total mechanical load is applied during the shod condition at a given weight. Deadlifting with a hexagonal bar does elicit greater PV and WORK, which can be taken into consideration when being implemented in training programs as mechanical work is related to the volume of work in a training program

Ex-nihilo: Obstacles Surrounding Teaching the Standard Model

The model of the Big Bang is an integral part of the national curriculum for England. Previous work (e.g. Baxter 1989) has shown that pupils often come into education with many and varied prior misconceptions emanating from both internal and external sources. Whilst virtually all of these misconceptions can be remedied, there will remain (by its very nature) the obstacle of ex-nihilo, as characterised by the question `how do you get something from nothing?' There are two origins of this obstacle: conceptual (i.e. knowledge-based) and cultural (e.g. deeply held religious viewpoints). The article shows how the citizenship section of the national curriculum, coming `online' in England from September 2002, presents a new opportunity for exploiting these.Comment: 6 pages. Accepted for publication in Physics E

Extending the scope of poly(styrene)-block-poly(methyl methacrylate) for directed self assembly

Directed self-assembly (DSA) is a promising technique for extending conventional lithographic techniques by being able to print features with critical dimensions under 10 nm. The most widely studied block copolymer system is polystyreneblock- polymethyl methacrylate (PS-b-PMMA). The system is well understood in terms of its synthesis, properties and performance in DSA. However, PS-b-PMMA also has a number of limitations that impact on its performance and hence scope of application. The primary limitation is the low Flory-Huggins polymer-polymer interaction parameter (Χ), which limits the size of features that can be printed by DSA. Another issue with block copolymers in general is that specific molecular weights need to be synthesized to achieve desired morphologies and feature sizes. We are exploring blending ionic liquid additiveswithPS-b-PMMAto increase the Χ parameter. This allows smaller feature sizes to be accessed by PS-b-PMMA. Depending on the amount of additive it is also possible to tune the domain size and the morphology of the systems. These findings may expand the scope of PS-b-PMMA for DSA

Entangled Rings

Consider a ring of N qubits in a translationally invariant quantum state. We ask to what extent each pair of nearest neighbors can be entangled. Under certain assumptions about the form of the state, we find a formula for the maximum possible nearest-neighbor entanglement. We then compare this maximum with the entanglement achieved by the ground state of an antiferromagnetic ring consisting of an even number of spin-1/2 particles. We find that, though the antiferromagnetic ground state does not maximize the nearest-neighbor entanglement relative to all other states, it does so relative to other states having zero z-component of spin.Comment: 19 pages, no figures; v2 includes new results; v3 corrects a numerical error for the case N=

Wearing Knee Sleeves During Back Squats Does Not Improve Mass Lifted or Affect Knee Biomechanics

Purpose:Knee sleeves have become widely popular in the exercise realm, especially for knee support during back squats. Knee sleeves are successful in providing frontal plane knee support during functional tasks, but have not been investigated in back squats. Knee wraps, a somewhat similar elastic material, provide elastic energy that increases weight lifted during back squats. Thus, it is possible the thick neoprene knee sleeves could prove advantageous for back squats. The purpose of this study was to examine the effects of knee sleeves on weight lifted, knee biomechanics, and muscle activations during back squats.Methods:Fifteen resistance trained men and women performed 1-repetition maximum (1-RM) squats to full depth and 80% 1-RM to full and parallel depths during two separate randomized sessions: with/without knee sleeves. Three-dimensional motion capture, force platforms, and electromyography recorded knee biomechanics and activations of the rectus femoris, vastus medialis, biceps femoris long head, and gluteus maximus during all squats.Results:Maximal weight lifted did not improve when using knee sleeves. Frontal plane knee biomechanics did not differ for 1-RM or submaximal squats to either depth between conditions. Knee external rotation moments during descent were larger with sleeves during submaximal squats. Reduced integrated ascent phase gluteus maximus activations occurred during both 1-RM and submaximal squats with knee sleeves.Conclusions:The results of this study show that wearing knee sleeves does not provide additive effects to weight lifted and do not appear to alter frontal plane mechanics during weighted back squats

Walking Biomechanics and Energetics of Individuals with a Visual Impairment: A Preliminary Report

Purpose. Although walking gait in sighted populations is well researched, few studies have investigated persons with visual impairments (VIs). Given the lack of physical activity in people with VIs, it is possible that reduced efficiency in walking could adversely affect activity. The purposes of this preliminary study were to (1) examine the biomechanics and energetics utilized during independent and guided walking in subjects with VIs, and (2) compare gait biomechanics between people with VIs and sighted controls. Methods. Three-dimensional motion capture and force platforms were used during independent and guided walking at self-selected speeds. Joint angles, moments, external work, and recovery were compared. Results. The VI group performed independent walking slower and with reduced stride lengths compared with guided walking and sighted controls. Hip range of motion and peak joint moments were reduced during independent walking in the VI group compared with guided walking and controls. Work was greater by 114%, 32%, and 16% in the VI group during independent than during guided walking. Recovery was 11% greater in guided vs. independent walking. Conclusions. In the presented preliminary study among 3 persons with congenital VIs, independent walking was a less efficient mode of walking compared with guided walking and that of sighted controls

Evaluating Loss to Follow-Up in Newborn Hearing Screening in a Southern State

Objective: The aim of this study was to examine loss to follow-up on the usage of diagnostic or intervention services for South Carolina infants screened or diagnosed with hearing loss and the risk factors associated with loss to follow up. Design: A cross sectional analysis of data from South Carolina was used to examine loss to follow-up on the use of audiologic evaluation services after initial newborn hearing screening and receipt of intervention services after confirmation of hearing loss. Results: Three percent (3.1%) of all children screened in the state of South Carolina did not pass their newborn hearing screening test in 2013 with less than half (49.1%) of those children not reported to have used audiologic diagnostic services within one month of their initial screening test. Factors significant with receipt of services include birth weight, mother’s education, insurance type, and rurality. The degree of hearing loss was a significant determinant of receiving intervention at some point in time. Conclusions: The highest risk children are “lost follow-up” for both the initial diagnostic services and follow-up intervention services in South Carolina. Interventions targeted at specific groups are needed to improve the delivery of hearing services and prevent a public health shortfall

Footwear Affects Conventional and Sumo Deadlift Performance

Barefoot weightlifting has become a popular training modality in recent years due to anecdotal suggestions of improved performance. However, research to support these anecdotal claims is limited. Therefore, the purpose of this study was to assess the differences between the conventional deadlift (CD) and the sumo deadlift (SD) in barefoot and shod conditions. On day one, one-repetition maximums (1 RM) were assessed for thirty subjects in both the CD and SD styles. At least 72 h later, subjects returned to perform five repetitions in four different conditions (barefoot and shod for both CD and SD) at 70% 1 RM. A 2 X 2 (footwear x lifting style) MANOVA was used to assess differences between peak vertical ground reaction force (VGRF), total mechanical work (WORK), barbell vertical displacement (DISP), peak vertical velocity (PV) and lift time (TIME) during the concentric phase. The CD displayed significant increases in VGRF, DISP, WORK, and TIME over the SD. The shod condition displayed increased WORK, DISP, and TIME compared to the barefoot condition. This study suggests that lifting barefoot does not improve performance as no differences in VGRF or PV were evident. The presence of a shoe does appear to increase the DISP and WORK required to complete the lift, suggesting an increased work load is present while wearing shoes

Duplex ultrasound imaging alone is sufficient for midterm endovascular aneurysm repair surveillance: A cost analysis study and prospective comparison with computed tomography scan

ObjectiveEarly in our experience with endovascular aortic aneurysm repair (EVAR) we performed both serial computed tomography scans and duplex ultrasound (DU) imaging in our post-EVAR surveillance regimen. Later we conducted a prospective study with DU imaging as the sole surveillance study and determined cost savings and outcome using this strategy.MethodsFrom September 21, 1998, to May 30, 2008, 250 patients underwent EVAR at our hospital. Before July 1, 2004, EVAR patients underwent CT and DU imaging performed every 6 months during the first year and then annually if no problems were identified (group 1). We compared aneurysm sac size, presence of endoleak, and graft patency between the two scanning modalities. After July 1, 2004, patients underwent surveillance using DU imaging as the sole surveillance study unless a problem was detected (group 2). CT and DU imaging charges for each regimen were compared using our 2008 health system pricing and Medicare reimbursements. All DU examinations were performed in our accredited noninvasive vascular laboratory by experienced technologists. Statistical analysis was performed using Pearson correlation coefficient.ResultsDU and CT scans were equivalent in determining aneurysm sac diameter after EVAR (P < .001). DU and CT were each as likely to falsely suggest an endoleak when none existed and were as likely to miss an endoleak. Using DU imaging alone would have reduced cost of EVAR surveillance by 29% ($534,356) in group 1. Cost savings of$1595 per patient per year were realized in group 2 by eliminating CT scan surveillance. None of the group 2 patients sustained an adverse event such as rupture, graft migration, or limb occlusion as a result of having DU imaging performed as the sole follow-up modality.ConclusionSurveillance of EVAR patients can be performed accurately, safely, and cost-effectively with DU as the sole imaging study