Relationships between lower-body muscle structure and, lower-body strength, explosiveness and eccentric leg stiffness in adolescent athletes

The purpose of the present study was to determine whether any relationships were present between lower-body muscle structure and, lower-body strength, variables measured during a counter-movement jump (CMJ) and squat jump (SJ), and eccentric leg stiffness, in adolescent athletes. Thirty junior male (n = 23) and female (n = 7) surfing athletes (14.8 ± 1.7 y; 1.63 ± 0.09 m; 54.8 ± 12.1 kg) undertook lower-body muscle structure assessment with ultrasonography and performed a; CMJ, SJ and an isomet-ric mid-thigh pull (IMTP). In addition, eccentric leg stiffness was calculated from variables of the CMJ and IMTP. Moderate to very large relationships (r = 0.46-0.73) were identified be-tween the thickness of the vastus lateralis (VL) and lateral gas-trocnemius (LG) muscles, and VL pennation angle and; peak force (PF) in the CMJ, SJ and IMTP. Additionally, moderate to large relationships (r = 0.37-0.59) were found between eccentric leg stiffness and; VL and LG thickness, VL pennation angle, and LG fascicle length, with a large relationship (r = 0.59) also present with IMTP PF. These results suggest that greater thick-ness of the VL and LG were related to improved maximal dy-namic and isometric strength, likely due to increased hypertro-phy of the extensor muscles. Furthermore, this increased thickness was related to greater eccentric leg stiffness, as the associated enhanced lower-body strength likely allowed for greater neuromuscular activation, and hence less compliance, during a stretch-shortening cycle

Electrochemical and shell-isolated nanoparticle enhanced Raman spectroscopy (SHINERS) approaches to probing novel catalytic nanomaterials

The surface sensitivity of asymmetric catalytic hydrogenation was investigated by utilising platinum single crystal surfaces and a novel in-situ analytical combination of cyclic voltammetry and shell-isolated nanoparticle enhanced Raman spectroscopy (SHINERS). The adsorption behaviour of aqueous Ethyl Pyruvate (EP) on a range of well-defined platinum surfaces, both with and without the presence of electrolytically evolved hydrogen and the chiral modifier Cinchonidine (CD), was monitored by both cyclic voltammetry and Raman spectroscopy. Two key surface intermediates of Ethyl Pyruvate (EP) were identified, the first being the half-hydrogenated state (HHS), reported previously by Attard et al. This intermediate is formed by the addition of a hydrogen atom to the keto-carbonyl group. The presence of second intermediate was also detected, this new species was not present in previous surface enhanced Raman spectroscopy (SERS) spectra and is attributed to chemisorbed EP bound in the μ2 (C, O) configuration. The degree of surface occupation of each intermediate was shown to be sensitive to the structure of the catalyst surface. The new μ2 (C, O) adsorbate was solely present in large quantities on pristine Pt{111} and Pt{100} surfaces. The HHS was only detected in the spectra on these surfaces after the introduction of low coordination defect sites through electrochemical roughening. Similar spectra were produced for intrinsically defected surfaces Pt{110}, Pt{321} and Pt{721}. This was an indicator that for the HHS to form, low coordination sites on the catalyst surface are required. The differing populations of both the intermediate states was further investigated by density functional theory (DFT) calculations, which supports the findings. The μ2 (C, O) state was found to have an appreciably higher stability on the Pt{111} in comparison to the Pt{221} surface. A mechanism was proposed that the μ2 (C, O) EP adsorbate was a precursor to the HHS, with the rates of hydrogen addition on the different surfaces impacting on the population of each adsorption state. With a slow rate of addition of the first hydrogen leading to a low steady-state population of the HHS on terrace sites. The impact of these findings was discussed with regards to enantioselective catalysis and catalyst design. The in-situ combination of cyclic voltammetry and SHINERS was applied to shape-controlled platinum nanoparticles, a more realistic catalytic system and a new asymmetric hydrogenation of α,β-unsaturated aldehydes with limited success. The potential and issues with this analytical approach are also discussed in depth

Increasing the Q-factor of Fabry-Perot etalons using focused Bessel beam illumination

Sensing and filtering applications often require Fabry-Perot (FP) etalons with an Interferometer Transfer Function (ITF) having high visibility, narrow Full Width at Half Maximum (FWHM), and high sensitivity. For the ITF to have these characteristics, the illumination beam must be matched to the modes of the FP cavity. This is challenging when a small illumination element size is needed, as typical focused beams are not matched to the FP cavity modes. Bessel beams are a potential alternative as their structure resembles the FP cavity modes while possessing a focused core. To study the feasibility of using Bessel beam illumination, in this Letter, ITFs of an FP etalon were measured using Bessel and Gaussian illumination beams. A Bessel beam with core size of 28 µm provided an ITF with visibility 3.0 times higher, a FWHM 0.3 times narrower, and a sensitivity 2.2 times higher than a Gaussian beam with waist 32 µm. The results show that Bessel beam illumination can provide ITFs similar to that of collimated beam illumination while also having with a focused core.</p

Tracking 6 Weeks of training/surfing sessions of adolescent competitive surfers: Just what are these young surfers up to?

The assessment of weekly and even monthly surf practice/training hours is vital for understanding the loads these up and coming surfers endure. Such information will help understand what kind of training these athletes are undertaking, how long they are surfing, what they consider training, and also areas that should be improved upon in terms of specific training. The purpose of this study was to establish surfers\u27 training hours in terms of strength, balance and conditioning hours, as well as surfing hours, coached hours and competition hours. The monitoring of the athletes will provide insights into the weekly surf hours compared to land-based training these athletes do.https://ro.ecu.edu.au/ecuposters/1008/thumbnail.jp

Assessing depleted uranium (DU) contamination of soil, plants and earthworms at UK weapons testing sites

Depleted uranium (DU) weapons testing programmes have been conducted at two locations within the UK. An investigation was therefore carried out to assess the extent of any environmental contamination arising from these test programmes using both alpha spectrometry and mass spectrometry techniques. Uranium isotopic signatures indicative of DU contamination were observed in soil, plant and earthworm samples collected in the immediate vicinity of test firing points and targets, but contamination was found to be localised to these areas. The paper demonstrates the superiority of the 235U:238U ratio over the 234U:238U ratio for identifying and quantifying DU contamination in environmental samples and also describes the respective circumstances under which alpha spectrometry or mass spectrometry may be the more appropriate analytical tool

The validity and inter-unit reliability of custom-made SurfTraX GPS units and use during surfing

The purposes of the study were to: i) gain further understanding of the movement patterns during surfing using custom made GPS units which are designed for surfing (SurfTraX, Gold Coast, Australia), and ii) determine the validity and inter-unit reliability of these units.https://ro.ecu.edu.au/ecuposters/1009/thumbnail.jp

Comparison of the 400 metre timed endurance surf paddle between elite competitive surfers, competitive surfers and recreational surfers

Surf competitions demand the ability to out paddle opposition to gain an optimal position for wave take offs. Those who can out paddle a heat opponent and catch waves at the most critical point when breaking are likely to maximize their scoring potential. Currently appropriate and valid testing protocols evaluating the physiological fitness of surfing athletes are not well established. The purpose of this study was to determine whether the testing procedure of a pool based, 400 endurance time trial is more appropriate (compared to geometry testing) given the nature of the sport, and pride a test that is a better discriminator of performance.https://ro.ecu.edu.au/ecuposters/1010/thumbnail.jp

Effect of four weeks detraining on strength, power, and sensorimotor ability of adolescent surfers

Background: Surfing is a high skill sport that requires a considerable amount of time in a variety of ocean conditions to help develop the fundamental techniques. Objective: The purpose of this study was to investigate the effect of four weeks of detraining on strength, power, and sensorimotor ability in adolescent surfers. Methods: Nineteen adolescent surfers (13.8 A 1.7 y, 53.6 A 10.8 kg and 165.1 A 8.9 cm) participated in four weeks of detraining (surfing participation maintained but resistance training ceased) following seven weeks of periodized resistance training. Maximal isometric strength, power, and sensorimotor ability pre-test results were determined from the conclusion (post-test) of the first seven-week training block while post-test results were measured at the start (pre-test) of a second seven-week training block. Results: Four weeks of detraining significantly decreased the following variables: Vertical jump height by -5.26%, (p=0.037, d= 0.40), vertical jump peak velocity by -3.73% (p=0.001, d= 0.51), isometric strength by -5.5%, (p=0.012, d= 0.22), and relative isometric strength by -7.27% (p=0.003, d= 0.47). Furthermore, sensorimotor ability worsened, with a significant increase of 61.36% (p=0.004, d= 1.01), indicating that athletes took longer to stabilize from a dynamic landing task. Conclusions: This demonstrates that surfing, in the absence of resistance training, is not a sufficient training stimulus to maintain physical characteristics. Adolescent surfers with a relatively low training age should avoid cessation of resistance training and strive to maintain consistent resistance training in conjunction with surf training in order to avoid negative decrements in physical characteristics that are associated with surfing performance

Scoring Analysis of the Men’s 2013 World Championship Tour of Surfing

The study compared scores obtained by the 10 highest and lowest ranked athletes on the men’s 2013 World Championship Tour (WCT) of surfing. Significant differences (p\u3c.001) were identified between the two groups’ average wave scores, average total scores and total heats competed. In addition, the average standard deviation (SD) of each surfer’s wave score was significantly different (p = .020) between the two groups. Significant moderate correlations were identified between athletes’ average placing and the SD of their wave scores (r = .596, p = .006), and total heat scores (r=.474, p=.035). Repeated measures ANOVA also revealed significant differences between heat scores obtained during the final and all previous rounds (p \u3c .001-.041). In conclusion, higher ranked surfers achieved higher wave scores and heat totals, and were more consistent in scoring. On average, a 1.04 point increase per wave score would allow a bottom 10 ranked surfer to reach the top 10, a small but impactful gain

RELEVANCE, RELIABILITY AND LIMITATIONS OF A DROP AND STICK LANDING ANALYSIS

The vertical force data from a drop and stick landing can be used to derive a number of variables. Previous studies have generally focused on the time to stabilization and peak force aspects, and issues related to reliability have been reported. This study investigated reliability for time to stabilisation, peak force, time to peak force, stiffness, rate of force dissipation, impulse and eccentric power (EP) among five professional elite surfing athletes. This data was also compared to data of aerial success in World Championship Tour competitions. The results revealed the best relationship between relative stiffness as well as eccentric power and completion rate of aerial manoeuvres. Further, eccentric power had the best reliability of the variables and may therefore be an interesting variable to study further