Nonlocal Teleparallel Cosmology

Even though it is not possible to differentiate General Relativity from Teleparallel Gravity using classical experiments, it could be possible to discriminate between them by quantum gravitational effects. These effects have motivated the introduction of nonlocal deformations of General Relativity, and similar effects are also expected to occur in Teleparallel Gravity. Here, we study nonlocal deformations of Teleparallel Gravity along with its cosmological solutions. We observe that Nonlocal Teleparallel Gravity (like nonlocal General Relativity) is consistent with the present cosmological data obtained by SNe Ia + BAO + CC + $H_0$ observations. Along this track, future experiments probing nonlocal effects could be used to test whether General Relativity or Teleparallel Gravity give the most consistent picture of gravitational interaction.Comment: Accepted for publication in EPJC. Some small changes and references adde

TWENTY- FIVE YEAR TRENDS OF AUTHORSHIP AND SAMPLING IN ISBS PROCEEDINGS

This study documented the trends in authorship and sampling in ISBS Proceedings over the last 25 years. Original research articles of the 1984, 1989, 1994, 1999, 2004, and 2009 proceedings were reviewed for data on authors, sample sizes, sample-author ratio, and rates of single authorship and hyperauthorship (6 or more). Narrative reviews, modeling papers, and technical notes, were excluded from analysis. The mean number of authors per paper significantly increased (71%), along with increased rates of hyperauthorship, and a decline in rates of single authorship (92%) since 1984. Sample sizes varied widely across papers and did not appear to change over time. Increased collaboration in sports biomechanics has not increased sample sizes of original research published in ISBS Proceedings

Validity of IPhone Apps to Measure Knee Range of Motion in Clinical Settings

poster abstractRange of motion (ROM) of joints is a measure of musculoskeletal function in clinical and athletics settings. ROM in uniaxial joints is measured using a two-arm goniometer (GON). Although GON are inexpensive and can be used in different planes, there are limitation in accuracy and reproducibility. New IPhone apps have been developed to measure ROM using photography (PT tools, Dr.Goniometer and Photogoniometer), or the accelerometry and they also provide a permanent record of the measurement. The purpose of this study to compare the accuracy of the several IPhone apps against standard clinical [goniometer (GON)] and laboratory [electro-goniometer (EGON)] methods of measuring ROM. An EGON was attached the knee of 15 subjects knee while the performed five trials of knee extensionflexion). Three photography and one accelerometer based apps were compared against the EGON. The EGON data were compared against the GON used in clinical settings. Intraclass correlation (ICC) between methods and the Bland-Altman method (BAM) of assessing clinical agreement were used to determine validity. The ICC between the EGON and GON was r =.969 and with a BAM showing good clinical agreement between the two techniques. ICC of the photography based apps ranged from (.709-.721) and the accelerometer based goniometer was .671. The results of the BAM showed moderate to poor agreement between the methods, which indicate the some of the apps may not be suitable to use in clinical settings. The small screen size of the IPhone makes it difficult to accurately identify the joints centers. Small errors on placing the joint centers can lead to large errors of the knee joint angle. Accelerometer based apps are difficult to align and can be affected by muscle and adipose tissue of leg. It is possible that photography based apps when used on an IPad will provide better accuracy and be suitable to clinical settings

COMPARISON OF TWO METHODS OF MANUAL DIGITIZATION ON ACCURACY AND TIME OF COMPLETION

The purpose of this study was to compare the accuracy and time efficacy of two methods of manual digitization (frame by frame, FXF and points over frame, POF). Two groups (experienced, N=20 and inexperience, N= 20) digitized markers using the FXF and POF method. The markers were digitized automatically using software HUMAN and the coordinates from the automatic digitizing were the true values and the manually digitized values were the measured values. These coordinates were used to compute an average root mean square (RMS) value for each subject. An ANOVA (Group x Method) was used to analyze the difference between digitizing time and RMS values. The POF method was more accurate than the FXF method in all of the landmarks analyzed. The advantage of the POF method lies in the ability of the subjects to continuously track the same point throughout the trial

Shock Absorption Properties of Soccer Headgear

poster abstractSoccer have gained tremendous success in the US with more than 3 million registered youth playing this year. With the concurrent increase of concussion awareness, manufactures of soccer apparel have introduced headgear to help dissipate forces from impacts with the ball as well as other surfaces such as body parts, ground, or goal posts. Most manufactures claim that such headgear can significantly reduce impact forces by as much of 50% during a collision. Therefore, the purpose of this study was to evaluate the shock absorption properties of three commercially available soccer headgear [Full Gear 90 (F90), Head blast soccer band (HB), and Forcefield headband (FF)]. A drop test was used to the simulate headsurface collision. A hard medicine ball weighing 2.5 kg was dropped from distance of 1 meter onto the surface of an AMTI force platform. The force platform recorded the magnitude of the force at a sampling rate of 1000 Hz. Ten trials for each conditions (no head gear-control, F90, HB and FF) were recorded and the impulse and maximum impact force were calculate using SigmaPlot. Oneway-ANOVA were used to determine significant differences in force and impulse across headgear. Although significant difference were found between the headgears for impulse and maximum force, overall these difference were minimal. There were less than a 10% reduction in maximum force and 4% reduction in impulse. Manufacturer’s claims of 50% reduction in impact forces seem to be unfounded. There is no scientific evidence that suggest that soccer headgear reduce the risk in injuries

EFFECTS OF LEG DOMINANCE ON THE SINGLE LEG HOP FUNCTIONAL TEST IN NON-INJURED ADULTS

The purpose of this study was to determine the effects of leg dominance on the single leg hop (SLH) functional test used in ACL rehabilitation. Twenty-two subjects performed four manipulative, and two standing balance tests to determine leg dominance; and three trials of a standing broad jump and the single leg hop test on both lower limbs. Ground reaction forces were measure using two force platforms (AMTI) and the distance jumped were recorded. T-tests for dependent measure (SPSS) were used to determine difference between dominant and non-dominant limb. Subjects were able to significantly jump farther, produce more vertical and horizontal ground reaction forces when using the dominant leg, except when they jumped from both legs. Clinicians should take in consideration the effects of leg dominance on the single leg hop test results

EFFECTS OF LEG DOMINANCE ON THE SINGLE LEG HOP FUNCTIONAL TEST IN NON-INJURED ADULTS

The purpose of this study was to determine the effects of leg dominance on the single leg hop (SLH) functional test used in ACL rehabilitation. Twenty-two subjects performed four manipulative, and two standing balance tests to determine leg dominance; and three trials of a standing broad jump and the single leg hop test on both lower limbs. Ground reaction forces were measure using two force platforms (AMTI) and the distance jumped were recorded. T-tests for dependent measure (SPSS) were used to determine difference between dominant and non-dominant limb. Subjects were able to significantly jump farther, produce more vertical and horizontal ground reaction forces when using the dominant leg, except when they jumped from both legs. Clinicians should take in consideration the effects of leg dominance on the single leg hop test results

De la agroindustria a la agroecología: una reflexión para el caso ecuatoriano

La presente, consiste en una investigación documental, que estudia dos agrofilosofías, por un lado, la agricultura industrial –cuyo sistema es hegemónico en el mundo-, la cuál, tiene por objetivo la maximización de los beneficios –por medio de la maximización de la producción-. Por otro lado, la agricultura agroecológica, la cuál, tiene por objetivo la sostenibilidad de la producción. Como se verá, estas respectivas premisas, tienen consecuencias muy diferentes, tanto en los ámbitos económico, como social, ambiental, e incluso ontológico, esta investigación, tiene por objeto presentarlas y examinarlas, para su comparación y juicio

Effects of physical training on proprioception in older women

Older adulthood is accompanied by declines in muscular strength, coordination, function, and increased risk of falling. Resistance training increases muscular strength in this population but its effect on proprioception is unknown. To evaluate the effect of resistance training on proprioception, community dwelling older women completed a three-month exercise study. A resistance training (RT) group (N=19) underwent supervised weight training three times per week while a non-strength trained control (NSTC) group (N=19) performed range-of-motion activities that mimicked the movements of the RT group without the benefit of muscle loading. Subjects were evaluated at baseline, 6, and 12 weeks for strength and proprioception. Muscular strength was assessed by measuring the subject’s one repetition maximum performance on four different exercises. Static proprioception was measured by the subject’s ability to reproduce a target knee joint angle while dynamic proprioception was measured by the subject’s ability to detect passive knee motion. The RT group made significant strength improvements compared to the NSTC group. Proprioception significantly improved in both groups by 6 weeks. Our findings suggest that improvements in proprioception can be obtained via regular activity that is independent of heavy muscle loading

ENERGY RETURN OF DIFFERENT SHAPES OF TRACK SPIKES

Different track spike designs (pin, pyramid, post, Christmas tree, and modified Christmas tree) are all touted as being advantageous for track and field performance, but these claims have not been tested and reported in peer-reviewed literature. The purpose of this study was to examine how track spike design impacted energy return on a Mondo track surface. Load-deformation curves of the spikes driven by a machine into the track surface were determined and the energy absorbed and the energy returned by each spike was calculated. On the Mondo track surface, the modified Christmas tree design generated significantly more energy return than the other spike designs while the pin spike absorbed (and therefore returned) significantly less energy than the other spike designs. This information could useful for athletes and coaches looking to enhance performance on a Mondo track