Assessment of competitive requirements, repeated sprint paddle ability and trainability of paddling performance in surfers

Studies examining the physical demands of surfing, the physiological characteristics of surfers, training techniques and various indices important to surfing performance are limited and characterised by methodological discrepancies. This thesis consists of five studies to assess the competitive requirements, test specific repeat sprint fitness and the trainability of sprint paddling in surfers. Initially an understanding of surfing movement patterns and a determination of the reliability and validity of custom-made GPS units was established (SurfTraX, Gold Coast, Australia) (Study 1: The validity and inter-unit reliability of custom-made SurfTraX GPS units and use during surfing). Durations, intensities, external loads and velocity of movements during competitive surfing were then examined (Study 2: Workloads of competitive surfing: A performance analysis of three surfing competitions). During competition surfers paddle 44% of the total time and have a significantly higher work to rest ratio at a beach-break compared to point-breaks. Further, point-breaks involve longer continuous durations of paddling, with significantly longer rides, compared to the beachbreak. Data from Study 2 aided in forming the rationale for developing and determining the reliability of a novel repeat sprint paddle test (RSPT) (Study 3: The repeat-sprint paddle test: A protocol for measuring surfing athletes’ sprint paddle performance). With lacking appropriate and valid testing protocols for evaluating physiological qualities in surfing athletes, Study 3 determined that the measurements of RSPT total time, best 15m time, and peak velocity from recreational and competitive surfers were reliable between days. Additionally, the smallest worthwhile change ranged from 0.02 to 2.7 s, demonstrating high sensitivity in detecting performance changes. After determining the reliability of the RSPT, this study investigated the durations that adolescent competitive surfers spend surfing and physically training. In the pilot study (Study 4: Tracking 6 Weeks of Training/Surfing Sessions of Adolescent Competitive Surfers: Just what are these young surfers up to?) adolescent surfers provided details on the amount of time spent free surfing, being coached, competing, strength training, conditioning and undertaking balance work over six weeks. It was found that adolescent surfers spent 14 more hours surfing than doing any form of land-based training, including no form of specific paddle training. Following the conclusions of Study 4, Study 5 examined the effectiveness of implementing structured training on the paddling abilities of adolescent surfers (Study 5: Five weeks of sprint and high intensity interval training improves paddling performance in adolescent surfers). It was discovered that high intensity interval training (HIT) (30 s sprint paddling) decreased athletes 400m endurance paddle time, and sprint interval training (SIT) (10 s sprint paddling) decreased the total RSPT time. Such training can be implemented to improve aerobic and repeat sprint paddle ability, which are key aspects of the sport. Additionally, the 400m paddle and RSPT can possibly discriminate between aerobic and anaerobic training adaptations, with aerobic gains likely from HIT and anaerobic gains likely from SIT. Overall, this thesis established greater in-depth information on competitive surfing, an innovative and reliable test to assess repeat sprint ability, and two training methods that produced beneficial sprint and endurance paddle improvements

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

Mapping the community : use of research evidence in policy and practice

Abstract: The use of research evidence (URE) in policy and practice is relevant to many academic disciplines, as well as policy and practice domains. Although there has been increased attention to how such evidence is used, those engaged in scholarship and practice in this area face challenges in advancing the field. This paper attempts to “map the field” with the objective of provoking conversation about where we are and what we need to move forward. Utilizing survey data from scholars, practitioners, and funders connected to the study of the use of research evidence, we explore the extent to which URE work span traditional boundaries of research, practice, and policy, of different practice/policy fields, and of different disciplines. Descriptive and network analyses point to the boundary spanning and multidisciplinarity of this community, but also suggest exclusivity, as well as fragmentation among disciplines and literatures on which this work builds. We conclude with opportunities for to improve the connectedness, inclusiveness, relationship to policy and practice, and sustainability of URE scholarship

Competitive surfing: a physiological profile of athletes and determinants of performance

Despite a huge growth in competitive surfing there is still a paucity of research available to underpin assessment and conditioning practice. Limited research investigating surfers’ aerobic and anaerobic fitness provides an initial insight into the physiological demands of surfing; however it is limited in terms of competitive surfing and is characterized by methodological discrepancies. Likewise performance analysis has not been utilized extensively in surfing. Information available to-date suggests that competitive surfing is characterized by repeat high intensity intermittent bouts of paddling interspersed with moderate and high heart rates. Additionally, research evidence indicates that surfers possess moderately high aerobic fitness levels, comparable to other athletic groups such as competitive swimmers and surf life savers. To understand more about the sport of surfing, fundamental research into competitive surfing is needed. Therefore, the objectives of this study were to use methods of performance analysis to measure the physical outputs, workloads and activity patterns of elite surfers during competitions, and to specifically measure their anaerobic power output and peak oxygen uptake (VO2peak) on a modified kayak ergometer, and the relationship between these outputs and surfing performance. The study investigated the performance of surfing athletes during competitive surfing events. Twelve national ranked surfers were fitted with heart rate monitors and Global Positioning System (GPS) units and videoed during two sanctioned competitions. From the 32 videos analysed the greatest amount of time spent during surfing was paddling 54 ± 6.3%. Remaining stationary represented 28 ± 6.9% of the total time, wave riding and paddling for a wave represented only 8 ± 2%, and 4 ± 1.5% respectively. Surfers spent 61 ± 7% of the total paddling bouts and 64 ± 6.8% of total stationary bouts between 1 - 10 seconds. The average speed recorded via GPS for all subjects was 3.7 ± 0.6 km/h, with an average maximum speed of 33.4 ± 6.5 km/h (45 km/h was the peak). Surfers spent 58 ± 9.9% of the total speed zones between 1 – 4 km/h. The average distance covered from the two events combined was 1605 ± 313.5 meters. During the heats, surfers spent 60% of the total time between 56% and 74% of age predicted heart rate maximum (HRmax), 19% above 46% HRmax and approximately 3% above 83% HRmax. The mean HR during the surf competitions was 139.7 ± 11. b.min-1 (64.4% HRmax), with a (mean) peak of 190 ± 12. b.min-1 (87.5% HRmax). The aerobic VO2peak uptake and anaerobic peak power of nationally ranked surf athletes was determined over multiple testing occasions using a customized surf-paddle specific, kayak ergometer. Eight national level surfers participated in the incremental VO2peak test and 20 participated in the anaerobic power test. A kayak ergometer was modified with a surfboard and hand paddles, in an attempt to simulate a surfing-specific paddling action. The subjects’ peak power (W) output calculated via the kayak ergometer computer was 205 ± 54.3 W, during a 10 second maximal intensity simulated paddle. A key finding from the current study was the significant relationship between surfers season ranking and anaerobic peak power output (r= -0.55, P= 0.02). Although correlations do not imply cause and effect, such a finding provides theoretical support for the importance of anaerobic paddling power in assessment batteries and conditioning practice for surf athletes. During the incremental VO2peak uptake test, subjects recorded a VO2peak of 44.0 ± 8.26 mL/kg/min, a result similar to previous studies. We found that there was no significant correlation between the surfers’ season ranking and aerobic VO2peak values, or aerobic peak power outputs. Thus suggesting that peak oxygen uptake and peak aerobic power are not defining measures of surfing ability. In conclusion, competitive surfing involves repeated measures of low intensity paddling, followed by intermittent high intensity bouts of all out paddling intercalated with relatively short recovery periods, combined with intermittent breath holding. Paddle power is conceivably important for competitive surfing athletes due to the significant relationship between surfers’ season rank and peak anaerobic power. The ability to produce maximal power might improve surfing performance by allowing more powerful surf athletes to paddle and catch waves that lower ranked competitors miss

Adaptive Optics pre-compensated laser uplink to LEO and GEO

We present the results from a Monte Carlo computer simulation of adaptive optics (AO) pre-compensated laser uplink propagation through the Earth’s atmospheric turbulence from the ground to orbiting satellites. The simulation includes the so-called point-ahead angle and tests several potential AO mitigation modes such as tip/tilt or full AO from the downlink beam, and a laser guide star at the point ahead angle. The performance of these modes, as measured by metrics relevant for free-space optical communication, are compared with no correction and perfect correction. The aim of the study is to investigate fundamental limitations of free-space optical communications with AO pre-compensation and a point-ahead angle, therefore the results represent an upper bound of AO corrected performance, demonstrating the potential of pre-compensation technology. Performance is assessed with varying launch aperture size, wavelength, launch geometry, ground layer turbulence strength (i.e. day/night), elevation angle and satellite orbit (Low-Earth and Geostationary). By exploring this large parameter space we are able examine trends on performance with the aim of informing the design of future optical ground stations and demonstrating and quantifying the potential upper bounds of adaptive optics performance in free-space optical communications

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

First On-Sky Demonstration of a Scintillation Correction technique using Tomographic Wavefront Sensing

Scintillation noise significantly limits high precision ground-based photometry of bright stars. In this paper we present the first ever on-sky demonstration of scintillation correction. The technique uses tomographic wavefront sensing to estimate the spatial-temporal intensity fluctuations induced by high altitude optical turbulence. With an estimate of the altitudes and relative strengths of the turbulent layers above the telescope, the wavefront sensor data from multiple guide stars can be combined to estimate the phase aberrations of the wavefront at each altitude through the use of a tomographic algorithm. This 3D model of the phase aberrations can then be used to estimate the intensity fluctuations across the telescope pupil via Fresnel propagation. The measured photometric data for a given target within the field of view can then be corrected for the effects of scintillation using this estimate in post-processing. A simple proof-of-concept experiment using a wavefront sensor and a stereo-SCIDAR turbulence profiler attached to the 2.5m Isaac Newton Telescope was performed for a range of exposure times using the Orion Trapezium cluster as the reference stars. The results from this on-sky demonstration as well as simulations estimating the expected performance for a full tomographic AO system with laser guide stars are presented. On-sky the scintillation index was reduced on average by a factor of 1.9, with a peak of 3.4. For a full tomographic system we expect to achieve a maximum reduction in the scintillation index by a factor of ∼25

Optical sparse telescope arrays and scintillation noise

Fresnel propagation of starlight after it passes through high altitude turbulence in the Earth’s atmosphere results in random fluctuations of the intensity at ground level, known as scintillation. This effect adds random noise to photometric measurements with ground-based optical telescopes. Spatial correlation of the intensity fluctuations means that the fractional photometric noise due to scintillation may be substantially smaller for a sparse array of small aperture telescopes than for a single large aperture of the same total area. Assuming that the photometric noise for each telescope is independent, averaging the light curves measured by N telescopes reduces the noise by a factor of N−−√⁠. For example, for bright stars, the signal-to-noise ratio of a 2.54 m telescope can be achieved for an array of thirty 20 cm telescopes if the scintillation noise measured for each telescope is uncorrelated. In this paper, we present results from simulation and from observations at the Isaac Newton Telescope. These explore the impact that several parameters have on the measured correlation of the scintillation noise between neighbouring telescopes. We show that there is significant correlation between neighbouring telescopes with separations parallel to the wind direction of the dominant high altitude turbulent layer. We find that the telescopes in an array should be separated by at least twice their aperture diameter so that there is negligible correlation of the photometric noise. We discuss additional benefits of using sparse telescope arrays, including reduced cost and increased field of view

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