2,532 research outputs found
Comparison of kinematics and electromyographic activity in the last repetition during different repetition maximums in the bench press exercise
The barbell bench press is often performed at different repetition maximums (RM). However, little is known about the last repetition of these repetition maximums in terms of movement kinematics and electromyographic activity in the bench press. This study compared kinematics and electromyographic activity during the last repetition of 1-RM, 3-RM, 6-RM, and 10-RM on the barbell bench press. Twelve healthy recreationally bench press-trained males (body mass: 84.3 ± 7.8 kg, age: 23.5 ± 2.6 years, height: 183.8 ± 4.2 cm) performed the bench press with a self-chosen grip width with four different repetition maximums. The participants bench pressed 96.5 ± 14.1, 88.5 ± 13.0, 81.5 ± 12.3, and 72.8 ± 10.5 kg with the 1-RM, 3-RM, 6-RM, and 10-RM. No differences were found between the bench press conditions in kinematic or electromyographic activity, except for the 10-RM, where a higher barbell velocity was observed at peak barbell deacceleration and first minimum barbell velocity (p †0.05) compared to the 1-RM and 3-RM. Overall, triceps medialis activity increased, whereas biceps brachii activity decreased from the pre-sticking to post-sticking region for all bench conditions (p †0.05). Since slower barbell velocity was observed in the sticking region for the 1-RM and 3-RM conditions compared to the 10-RM condition, we suggest training with these repetition maximums to learn how to grind through the sticking region due to the principle of specificity when the goal is to enhance maximal strength.publishedVersio
Association of performance in strength and plyometric tests with change of direction performance in young female team-sport athletes
publishedVersio
HST Imaging of Globular Clusters in the Edge--on Spiral Galaxies NGC 4565 and NGC 5907
We present a study of the globular cluster systems of two edge-on spiral
galaxies, NGC4565 and NGC5907, from WFPC2 images in the F450W and F814W
filters. The globular cluster systems of both galaxies appear to be similar to
the Galactic globular cluster system. In particular, we derive total numbers of
globular clusters of N_{GC}(4565)= 204+/-38 {+87}{-53} and
N_{GC}(5907)=170+/-41 {+47}{-72} (where the first are statistical, the second
potential systematic errors) for NGC4565 and NGC5907, respectively. This
determination is based on a comparison to the Milky Way system, for which we
adopt a total number of globular clusters of 180+/-20. The specific frequency
of both galaxies is S_N~0.6: indistinguishable from the value for the Milky
Way. The similarity in the globular cluster systems of the two galaxies is
noteworthy since they have significantly different thick disks and
bulge-to-disk ratios. This would suggest that these two components do not play
a major role in the building up of a globular cluster system around late-type
galaxies.Comment: Accepted for publication in the Astronomical Journal, 17 pages incl 5
figures, AAS style two columns. Also available at
http://www.eso.org/~mkissler, Color version of figure 1 only available at
http://www.eso.org/~mkissler (B/W version included
GPS-derived orbits for the GOCE satellite
The first ESA (European Space Agency) Earth explorer core mission GOCE (Gravity field and steady-state Ocean Circulation Explorer) was launched on 17 March 2009 into a sun-synchronous dusk-dawn orbit with an exceptionally low initial altitude of about 280km. The onboard 12-channel dual-frequency GPS (Global Positioning System) receiver delivers 1Hz data, which provides the basis for precise orbit determination (POD) for such a very low orbiting satellite. As part of the European GOCE Gravity Consortium the Astronomical Institute of the University of Bern and the Department of Earth Observation and Space Systems are responsible for the orbit determination of the GOCE satellite within the GOCE High-level Processing Facility. Both quick-look (rapid) and very precise orbit solutions are produced with typical latencies of 1day and 2 weeks, respectively. This article summarizes the special characteristics of the GOCE GPS data, presents POD results for about 2months of data, and shows that both latency and accuracy requirements are met. Satellite Laser Ranging validation shows that an accuracy of 4 and 7cm is achieved for the reduced-dynamic and kinematic Rapid Science Orbit solutions, respectively. The validation of the reduced-dynamic and kinematic Precise Science Orbit solutions is at a level of about 2c
Studies on mechanisms of augmentation of liver regeneration by cyclosporine and FK 506
Evidence could not be found of immune modulation of liver regeneration. The powerful immunosuppressive drug FK 506, which augments the response after partial hepatectomy in normal rats, had the same effect in T cellâdeficient nude rats. The cytotoxicity of natural killer cells in treated nude rats was not significantly changed by FK 506 therapy. However, the serum of FK 506âtreated nude rats increased hepatocyte proliferation when added to thirdâparty hepatocyte cultures, suggesting that FK 506 had induced a serum growth factor in the nude rats or had suppressed an inhibitory factor. A hypothesis was advanced that FK 506 (and cyclosporine) affects hepatic growth by nonimmunological pathways. (HEPATOLOGY 1991;14:140â143.) Copyright © 1991 American Association for the Study of Liver Disease
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