Landing performance and lower extremity injuries in competitive surfing

Competitive surfing involves highXrisk manoeuvres that may impose injury risk, especially in the lower extremity. Although the dynamic environment of surfing is a major factor of unpredictable determinants for injury risk, there may be athlete qualities with importance for prevention. Previous studies suggest that dynamic loading and landing tasks represent major risk factors, and should therefore be included in athlete assessments and risk analysis. The purpose of this thesis was to investigate landing tasks that may be related to surfing performance and injury risk. It involved studying manoeuvres and landing tasks to establish its relevance for surfing athletes, develop multifactorial assessment protocols, as well as observe mechanisms and factors influencing lower extremity injury risk in high performance surfing. Study 1 examined manoeuvres of the competitive season of the World Championship Tour, reporting on frequency and scores. Although reXentries were the most common manoeuvres, waves including aerial manoeuvres and tube rides scored higher on average; 7.40 ± 1.53 and ± 6.82 ± 2.13 respectively, compared to 5.03 ± 2.21 for turning manoeuvre waves. Therefore, aerial manoeuvres and barrel rides are necessary for high performance surfing Study 2 evaluated impact forces, accelerations and dorsiflexion range of motion in five different landing tasks. A drop and stick landing, two surf stance landings and two gymnastic type landings were performed by eleven competitive athletes. The peak acceleration was about 50% higher whilst landing on a board in a miniXtrampoline gymnastic exercise compared to a surf stance landing from a 50 cm box (p≤0.05). Furthermore, the dorsiflexion ranges of motion in the gymnastic type landings were lower than the other landing types (p≤0.05). The greater load observed in the more complex tasks indicate that the risk involved may be higher in these, compared to general landing tasks. Study 3 provided information of the circumstances of surfing injuries, by video analysis (N=13). Factors that were found to distinguish between injury situations and non-injury situations were deep knee flexion at water contact, upper body lateral displacement, knee valgus, perturbations in the landing and direction of board relative riding direction. For safety, athletes should practice landing competency and increase adaptability to sudden environmental changes. Study 4 describes the development of a model based on the five measures ankle dorsiflexion range of motion, lower body strength, and time to stabilisation, peak force and a frontal plane video analysis during a drop and stick landing. The model was based on normative data from 71 surfing athletes and developed into a score based on exponential functions for four groups of athletes (male, female, junior and senior). It was concluded easy to implement, and may be useful in the assessment of landing competency of surfing athletes. Study 5 was a prospective study of competitive surfing athletes, observing injuries during six months. Furthermore, the athletes (N=48) were tested on baseline assessments to reveal whether any of the variables could be useful as indicator of injury risk from closed kinetic chain movements. There were 22 injuries reported during the period, whereof 8 were categorised closed kinetic chain injuries. Two baseline measures were found to be potential risk factors; the model of landing qualities and bilateral squat asymmetry (p≤0.05). Athletes with excessively poor assessment results on landings and bilateral squat may be alerted of potential injury risk. Landing competency and other bilateral movements can be tested and trained in the land-based preparation of surfing athletes, and seem to be relevant for competitive surfing athletes. If excessively poor scores on these assessments expose the athlete to injury risk, then athletes should aim for satisfactory scores before successively training high-risk manoeuvres in the surfing context

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

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

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

Producing Feedstock for Biofuels: Land-Use and Local Environmental Impacts

This report covers Chalmers responsibilities for subtask 1.3 - land-use patterns as well as parts of subtask 3.4 – data for other environmental impacts, in the EU Biofuel Baseline projec

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

Fee Arrangements and Fee Shifting: Lessons From the Experience in Ontario

About one-third of oestrogen receptor alpha-positive breast cancer patients treated with tamoxifen relapse. Here we identify the nuclear receptor retinoic acid receptor alpha as a marker of tamoxifen resistance. Using quantitative mass spectrometry-based proteomics, we show that retinoic acid receptor alpha protein networks and levels differ in a tamoxifen-sensitive (MCF7) and a tamoxifen-resistant (LCC2) cell line. High intratumoural retinoic acid receptor alpha protein levels also correlate with reduced relapse-free survival in oestrogen receptor alpha-positive breast cancer patients treated with adjuvant tamoxifen solely. A similar retinoic acid receptor alpha expression pattern is seen in a comparable independent patient cohort. An oestrogen receptor alpha and retinoic acid receptor alpha ligand screening reveals that tamoxifen-resistant LCC2 cells have increased sensitivity to retinoic acid receptor alpha ligands and are less sensitive to oestrogen receptor alpha ligands compared with MCF7 cells. Our data indicate that retinoic acid receptor alpha may be a novel therapeutic target and a predictive factor for oestrogen receptor alpha-positive breast cancer patients treated with adjuvant tamoxifen

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