Kinematics of assisted and unassisted plyometric training of vertical jumping and rebounding in youth male football players –A six-week training study

The purpose of this study was to compare the kinematics of assisted and unassisted plyometric training of vertical jumping and rebounding activities following a six-week training intervention. 13 youth males from a professional football academy completed six weeks of either unassisted (n = 6) or band-assisted (n = 7) plyometric training sessions twice a week during their competitive season. Pre- and post-assessments of counter-movement jump (CMJ) height, 50 cm drop-jump (DJ50) ground contact time (GCT), jump height and reactive strength index (RSI), and submaximal-hopping (SMH) GCT, jump height and RSI were compared. Pre- and post-assessment ankle angle at touch-down (TD), peak flexion (PF) and mid-flight (MF) were also analysed for the submaximal-hop test only. Following training, significant main effects of time were observed for CMJ height, DJ50 GCT and MF ankle angle (p < 0.05) and a significant effect of group was observed for DJ50 RSI (p < 0.05). These results suggest that both unassisted and assisted plyometric training may be useful for enhancing the kinematics and technical performance of plyometric activities in a youth male football population

The Effect of Two Different Assisted Plyometric Programmes on Vertical Jumping Kinetics in Young Male Football Players

Assisted jumping is documented to improve lower body power, however no current research evaluates it from a skill development standpoint, with limited data evaluating assisted plyometrics. 15 youth football players were separated into a band assisted (BAP) (n = 8) or ground-based plyometrics (GBP) (n = 7) group. Both groups followed similar 6-week plyometric interventions. BAP used resistance bands to increase flight time during all jumps, while GBP performed bodyweight jumps. Participants completed countermovement jumps (CMJ), drop jumps (DJ) and a submaximal hopping (SH) test pre- and postintervention. Both groups significantly improved jump height and relative peak power in the CMJ (p < 0.05). Neither groups significantly improved reactive strength index (RSI) in the DJ or SH tests, however GBP had a significantly greater mean RSI compared to BAP in the post-test (p < 0.05). Overall, these data demonstrate that band assisted jump training (using a directly transferable assistance method) is effective at improving some vertical jumping kinetics. However, conflicting factors related to mechanical loading, biological maturity and the selected band assistance, limit definitive conclusions. Future research should consider replicating the current study and explore the reasons for the lack of difference between assisted and unassisted conditions

The path to Net Zero carbon emissions for veterinary practice

The urgent need to reduce greenhouse gas emissions in line with the Paris Agreement is a compelling reason for the entire veterinary profession to act on climate change because of its impact on animal health. The aim of this perspective is to provide a business framework that veterinary practices can use to implement the path to Net Zero carbon emissions. Practice management is identified as a key stakeholder capable of implementing significant change within the sector. Climate related business opportunities and challenges are identified and integrated into a stepwise process for practices to follow. The pathway requires establishing a culture of sustainability within the veterinary team, measuring and reporting emissions, setting targets and systematically prioritizing reductions. Practices can begin this process immediately by reducing emissions under direct control of the business (Scope 1) and emissions from electricity purchases (Scope 2). To complete the pathway, emissions from all other activities (Scope 3) will need to be reduced and offset. Reduction of Scope 3 emissions is more challenging and will require collaboration between all supply chain stakeholders. The progression of climate change is now inevitable and a proactive approach from veterinary leaders, in particular practice management, will provide new opportunities, manage risks and inspire the broader veterinary sector to join their efforts to achieve a better future for animal health

Hubble Space Telescope Imaging of the Circumstellar Nebulosity of T Tauri

Short-exposure Planetary Camera images of T Tauri have been obtained using broadband filters spanning the wavelength range 0.55-0.80 μm. The optically visible star lies very close to an arc of reflection nebulosity. The arc's northern arm extends approximately 5" from the star, while its southwestern arm appears brighter and extends only 2". The arc shows an approximate symmetry along an axis toward the west-northwest, the direction of Hind's Nebula and the blueshifted molecular outflow. The morphology of the reflected light is similar to models of scattered light within an illuminated, axisymmetric outflow cavity in a circumbinary envelope, viewed ≈ 45° from the outflow axis. However, our model images do not successfully account for the amount of limb brightening that is seen. No optical counterpart to the infrared companion is seen to a limiting magnitude of V = 19.6, which suggests A_V > 7 mag toward this source. There is no evidence for an optical tertiary, to a limiting ΔV = 5.1 mag fainter than the primary, at the position where such an object has been previously reported

Stellar Populations at the Center of IC 1613

We have observed the center of the Local Group dwarf irregular galaxy IC 1613 with WFPC2 aboard the Hubble Space Telescope in the F439W, F555W, and F814W filters. We find a dominant old stellar population (aged ~7 Gyr), identifiable by the strong red giant branch (RGB) and red clump populations. From the (V-I) color of the RGB, we estimate a mean metallicity of the intermediate-age stellar population [Fe/H] = -1.38 +/- 0.31. We confirm a distance of 715 +/- 40 kpc using the I-magnitude of the RGB tip. The main-sequence luminosity function down to I ~25 provides evidence for a roughly constant SFR of approximately 0.00035 solar masses per year across the WFPC2 field of view (0.22 square kpc) during the past 250-350 Myr. Structure in the blue loop luminosity function implies that the SFR was ~50% higher 400-900 Myr ago than today. The mean heavy element abundance of these young stars is 1/10th solar. The best explanation for a red spur on the main-sequence at I = 24.7 is the blue horizontal branch component of a very old stellar population at the center of IC 1613. We have also imaged a broader area of IC 1613 using the 3.5-meter WIYN telescope under excellent seeing conditions. The AGB-star luminosity function is consistent with a period of continuous star formation over at least the age range 2-10 Gyr. We present an approximate age-metallicity relation for IC 1613, which appears similar to that of the Small Magellanic Cloud. We compare the Hess diagram of IC 1613 to similar data for three other Local Group dwarf galaxies, and find that it most closely resembles the nearby, transition-type dwarf galaxy Pegasus (DDO 216).Comment: To appear in the September 1999 Astronomical Journal. LaTeX, uses AASTeX v4.0, emulateapj style file, 19 pages, 12 postscript figures, 2 tables. 5 of the figures available separately via the WW

Hubble Space Telescope Observations of the Draco Dwarf Spheroidal

We present an F606W-F814W color-magnitude diagram for the Draco dwarf spheroidal galaxy based on Hubble Space Telescope WFPC2 images. The luminosity function is well-sampled to 3 magnitudes below the turn-off. We see no evidence for multiple turnoffs and conclude that, at least over the field of the view of the WFPC2, star formation was primarily single-epoch. If the observed number of blue stragglers is due to extended star formation, then roughly 6% (upper limit) of the stars could be half as old as the bulk of the galaxy. The color difference between the red giant branch and the turnoff is consistent with an old population and is very similar to that observed in the old, metal-poor Galactic globular clusters M68 and M92. Despite its red horizontal branch, Draco appears to be older than M68 and M92 by 1.6 +/- 2.5 Gyrs, lending support to the argument that the ``second parameter'' which governs horizontal branch morphology must be something other than age. Draco's observed luminosity function is very similar to that of M68, and the derived initial mass function is consistent with that of the solar neighborhood.Comment: 16 pages, AASTeX, 9 postscript figures, figures 1 and 2 available at ftp://bb3.jpl.nasa.gov/pub/draco/. Accepted for publication in the Astronomical Journa