Evaluation and training of sensorimotor abilities in competitive surfers

Study 1: Development of a comprehensive performance testing protocol for competitive surfers Purpose: Appropriate and valid testing protocols for evaluating the physical performances of surfing athletes is not well refined. The purpose of this project was to develop, refine, and evaluate a testing protocol for use with elite surfers, including measures of anthropometry, strength and power, and endurance. Methods: After pilot testing and consultation with athletes, coaches and sport scientists, a specific suite of tests was developed. Forty-four competitive junior surfers (16.2±1.3 years, 166.3±7.3 cm, 57.9±8.5 kg) participated in this study involving a within-day repeated measures analysis, using an Elite Junior Group of 22 international competitors (EJG), to establish reliability of the measures. To reflect validity of the testing measures, a comparison of performance results was then undertaken between the EJG and an age-matched Competitive Junior Group of 22 nationally competitive surfers (CJG). Results: Percent Typical Error of Measurement (%TEM) for primary variables gained from the assessments ranged from 1.1-3.0%, with intra-class correlation coefficients ranging from 0.96- 0.99. One-way analysis of variance revealed that the EJG had lower skinfolds (p=0.005, d=0.9) compared to the CJG, despite no difference in stature (p=0.102) or body mass (p=0.827). The EJG were faster in 15 m sprint-paddle velocity (pd=1.3), had higher lower-body isometric peak force (p=0.04, d=0.7), and superior endurance paddling velocity (p=0.008, d=0.9). Conclusions: The relatively low %TEM of these tests in this population allows for high sensitivity to detect change. The results of this study suggest that competitively superior junior surfers are leaner, and possess superior strength, paddling power, and paddling endurance. Study 2: Comparison of physical capacities between non-selected and selected elite male competitive surfers for the national team Purpose: The purpose of this study was to determine whether a previously validated performance testing protocol for competitive surfers was able to differentiate between Australian elite junior surfers selected (S) to the national team, and those not selected (NS). Methods: Thirty-two elite male competitive junior surfers were divided into two groups (S=16; NS=16). The mean age, stature, body mass, sum of 7 skinfolds and lean body mass ratio (mean ± SD) were 16.17 ± 1.26 y, 173.40 ± 5.30 cm, 62.35 ± 7.40 kg, 41.74 ± 10.82 mm, 1.54 ± 0.35 for the S athletes and 16.13 ± 1.02 y, 170.56 ± 6.6 cm; 61.46 ± 10.10 kg; 49.25 ± 13.04 mm; 1.31 ± 0.30 for the NS athletes. Power (countermovement jump; CMJ), strength (isometric mid-thigh pull), 15 m sprint paddling, and 400 m endurance paddling was measured. Results: There were significant (p ≤ 0.05) differences between the S and NS athletes for relative vertical jump peak force (p=0.01, d=0.9), CMJ height (p=0.01, d=0.9), time to 5, 10, and 15 m sprint paddle, sprint paddle peak velocity (p=0.03, d=0.8; PV), time to 400 m (p=0.04, d=0.7) and endurance paddling velocity (p=0.05, d=0.7). Conclusions: All performance variables, particularly CMJ height, time to 5, 10, and 15 m sprint paddle, sprint paddle PV, time to 400 m and endurance paddling velocity can effectively discriminate between S and NS competitive surfers and this may be important for athlete profiling and training program design. Study 3: The development and evaluation of a drop and stick method to assess landing skills in various levels of competitive surfers The purpose of this study was to develop and evaluate a drop and stick (DS) test method and to assess dynamic postural control in senior elite (SE), junior elite (JE), and junior development (JD) surfers. Nine SE, 22 JE, and 17 JD competitive surfers participated in the study. The athletes completed five drop and stick trials barefoot from a pre-determined box height (0.5 m). The lowest and highest time to stabilisation (TTS) trials were discarded, and the average of the remaining trials were used for analysis. The SE group demonstrated excellent single measures repeatability (ICC=0.90) for TTS, whereas the JE and JD demonstrated good single measures repeatability (ICC 0.82 and 0.88, respectively). In regards to relative peak landing force (rPLF), SE demonstrated poor single measures reliability compared to JE and JD groups. TTS for SE (0.69 ± 0.13 s) group was significantly (p=0.04) lower than the JD (0.85 ± 0.25 s). There were no significant (p=0.41) differences in the TTS between SE (0.69 ± 0.13 s) and JE (0.75 ± 0.16 s) groups or between the JE and JD groups (p=0.09). rPLF for SE (2.7 ± 0.4 body mass; BM) group was significantly lower than the JE (3.8 ± 1.3 BM) and JD (4.0 ± 1.1 BM), with no significant (p=0.63) difference among the JE and JD groups. A possible benchmark approach for practitioners would be to use TTS and rPLF as a qualitative measure of dynamic postural control using a reference scale to discriminate amongst groups. Study 4: Effects of stable and unstable resistance training on strength, power, and sensorimotor abilities in adolescent surfers The purpose of this study was to investigate two different resistance-training interventions (unstable or stable) on strength, power, and sensorimotor abilities in adolescent surfers. Ten competitive female and male high school surfers were assessed before and after each of 2 x 7-week training intervention, using a within-subjects cross-over study design. Results for strength revealed no condition by time interaction or main effect for condition. However, there was a significant main effect for time, with significant strength gains post-training. There was a significant condition by time interaction for power exhibited as a significant decrease from pre- to post-training in the unstable condition, while the stable condition approached significant improvement. These results suggest that unstable and stable resistance training are equally effective in developing strength in previously untrained competitive surfers, but with little effect on sensorimotor abilities. However, unstable training is inferior for the development of lower body power in this population. Study 5: Effect of four weeks detraining on power, strength, and sensorimotor ability of adolescent surfers The purpose of this study was to investigate the effect of four weeks of detraining on power, strength, and sensorimotor ability in adolescent surfers. Nineteen adolescent surfers with an overall mean age, mass, and stature (mean ± SD) of 14.1 ± 1.6 y, 54.0 ± 10.8 kg and 165.1 ± 9.0 cm, respectively, volunteered to participate in four weeks of detraining (surfing participation maintained but resistance training ceased) following seven weeks of periodized resistance training. Power (vertical jump height; VJH), maximal isometric strength (isometric mid-thigh pull; IMTP), and sensorimotor ability (time to stabilization during a drop and stick (DS); TTS) 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. Four weeks of detraining significantly decreased the following variables: VJH by -5.26%, (p = 0.037, d = -0.40), vertical jump peak velocity by -3.73% (p = 0.001, d = -0.51), maximal isometric strength by -5.5%, (p = 0.012, d = -0.21), and relative maximal isometric strength by -7.27% (p = 0.003, d = -0.47). Furthermore, sensorimotor ability worsened, as assessed by TTS, with a significant increase of 61.36% (p = 0.004, d = 0.99), indicating athletes took longer to stabilize from a dynamic landing task. 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

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

Povezanost između snage trupa i pokazatelja sportske uspješnosti

Development of core muscle strength and power to improve sport performance has been a controversial issue yielding mixed results. The purpose of this study was to investigate the relationship between two core field tests emphasizing power and measures of sport performance. Participants were twenty healthy, recreationally active males (age 23.40±1.88 yrs, height 174.63±5.81 cm, mass 76.08±7.67 kg). Participants were tested on four performance variables (40-yd sprint, shuttle run [5-10-5], vertical jump, and 1RM back squat) and two core field tests (front abdominal power throw [FAPT] and side abdominal power throw [SAPT]). Results demonstrated significant moderate correlations between the FAPT and 1RM back squat (r=.652) and relative back squat (r=.509). No other significant correlations were found. Results indicate that although the FAPT and SAPT tests are easy to perform in the field, most, but not all, performance measures were unrelated to core power. In order to properly assess the core and its role in human performance, it is necessary to evaluate sport-specific muscle actions and movements.Razvijanje mišićne jakosti i snage trupa kako bi se unaprijedila sportska izvedba i uspješnost jest kontroverzan znanstveni i stručni problem istraživanje kojega daje miješane rezultate. Cilj je ovoga istraživanja bilo utvrđivanje povezanosti između dva terenska testa za procjenu snage trupa i pokazatelja sportske uspješnosti. Uzorak ispitanika činilo je 20 zdravih, rekreativno aktivnih muškaraca (dob 23,40±1,88 godina, tjelesna visina 174,63±5,81 cm, tjelesna masa 76,08±7,67 kg). Sportska uspješnost ispitanika procijenjena je četirima testovima (sprint na 40 jarda, shuttle run: 5-10-5 jarda, vertikalni skok i maksimalni stražnji čučanj), a snaga njihova trupa (core) procijenjena je dvama terenskim testovima (eksplozivno bacanje medicinke prema naprijed – FAPT, i eksplozivno bacanje medicinke strance – SAPT). Rezultati analiza su pokazali značajne umjerene korelacije između FAPT i maksimalnoga stražnjega čučnja (r=,652) i relativnoga stražnjega čučnja (r=,509). Nisu utvrđene značajne korelacije između ostalih testova. Rezultati pokazuju da, iako je terenske testove FAPT i SAPT vrlo lako provoditi, većina, ali ne i sve varijable koje procjenjuju sportsku uspješnost nisu u korelaciji sa snagom trupa procijenjenom navedenim testovima. Da bi se adekvatno procijenila snaga trupa i njena uloga u sportskoj izvedbi i uspješnosti, potrebno je vrednovati sportu svojstvene mišićne akcije i kretnje

Povezanost između snage trupa i pokazatelja sportske uspješnosti

Development of core muscle strength and power to improve sport performance has been a controversial issue yielding mixed results. The purpose of this study was to investigate the relationship between two core field tests emphasizing power and measures of sport performance. Participants were twenty healthy, recreationally active males (age 23.40±1.88 yrs, height 174.63±5.81 cm, mass 76.08±7.67 kg). Participants were tested on four performance variables (40-yd sprint, shuttle run [5-10-5], vertical jump, and 1RM back squat) and two core field tests (front abdominal power throw [FAPT] and side abdominal power throw [SAPT]). Results demonstrated significant moderate correlations between the FAPT and 1RM back squat (r=.652) and relative back squat (r=.509). No other significant correlations were found. Results indicate that although the FAPT and SAPT tests are easy to perform in the field, most, but not all, performance measures were unrelated to core power. In order to properly assess the core and its role in human performance, it is necessary to evaluate sport-specific muscle actions and movements.Razvijanje mišićne jakosti i snage trupa kako bi se unaprijedila sportska izvedba i uspješnost jest kontroverzan znanstveni i stručni problem istraživanje kojega daje miješane rezultate. Cilj je ovoga istraživanja bilo utvrđivanje povezanosti između dva terenska testa za procjenu snage trupa i pokazatelja sportske uspješnosti. Uzorak ispitanika činilo je 20 zdravih, rekreativno aktivnih muškaraca (dob 23,40±1,88 godina, tjelesna visina 174,63±5,81 cm, tjelesna masa 76,08±7,67 kg). Sportska uspješnost ispitanika procijenjena je četirima testovima (sprint na 40 jarda, shuttle run: 5-10-5 jarda, vertikalni skok i maksimalni stražnji čučanj), a snaga njihova trupa (core) procijenjena je dvama terenskim testovima (eksplozivno bacanje medicinke prema naprijed – FAPT, i eksplozivno bacanje medicinke strance – SAPT). Rezultati analiza su pokazali značajne umjerene korelacije između FAPT i maksimalnoga stražnjega čučnja (r=,652) i relativnoga stražnjega čučnja (r=,509). Nisu utvrđene značajne korelacije između ostalih testova. Rezultati pokazuju da, iako je terenske testove FAPT i SAPT vrlo lako provoditi, većina, ali ne i sve varijable koje procjenjuju sportsku uspješnost nisu u korelaciji sa snagom trupa procijenjenom navedenim testovima. Da bi se adekvatno procijenila snaga trupa i njena uloga u sportskoj izvedbi i uspješnosti, potrebno je vrednovati sportu svojstvene mišićne akcije i kretnje

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

Analytical study of the sth-order perturbative corrections to the solution to a one-dimensional harmonic oscillator perturbed by a spatially power-law potential Vper(x) = λxα

In this work, we present a rigorous mathematical scheme for the derivation of the sth-order perturbative corrections to the solution to a one-dimensional harmonic oscillator perturbed by the potential V-per(x) = lambda x(alpha), where alpha is a positive integer, using the non-degenerate time-independent perturbation theory. To do so, we derive a generalized formula for the integral I = integral(+infinity)(-infinity)x(alpha)exp(-x(2))H-n(x)H-m(x)d(x), where H-n(x) denotes the Hermite polynomial of degree n, using the generating function of orthogonal polynomials. Finally, the analytical results with alpha = 3 and alpha = 4 are discussed in detail and compared with the numerical calculations obtained by the Lagrange-mesh method