Farley, Oliver; Harris, Nigel K.; Kilding, Andrew E.
With the growth in competitive surfing internationally, there has been an increase in the attention given to the conditioning of competitive surfing athletes. Surfing is an intermittent, high performance sport requiring the athlete to perform multiple endurance paddling bouts and explosive paddling bursts to catch the wave. During a session, athletes are required to paddle out through the breaking waves to the take-off zone (where the ocean swell forms into a wave for the surfer to catch and ride), which can require up to 10 minutes of strenuous work. In addition to this, repeated duck-diving requiring breath holding under advancing broken waves adds to the intensity of surfing (4–12). Once the surfer has reached the take-off zone, durations of continuous paddling to the waves, against currents, and moving to different locations will ensue. These activities stress the aerobic and anaerobic energy systems, especially when repeatedly paddling to gain enough momentum to catch the forming wave. Therefore, it has been proposed that surf athletes require muscular endurance, power of the upper torso, and excellent cardiorespiratory endurance and recovery abilities (6). Surf athletes' aerobic endurance measures via peak oxygen uptake (V[Combining Dot Above]O2peak) have been quantified using a variety of protocols and testing methods (swim bench ergometery [4,9], tethered board paddling and hand cranking , and modified kayak ergometer arm paddling ) with a range of values observed (recreational: 37.8 ± 4.5 ml·kg−1·min−1 , 54.2 ± 10.2 ml·kg−1·min−1 ; competitive: 39.5 ± 3.1 ml·kg−1·min−1 , 40.4 ± 2.9 and 41.6 ± 4.0 ml·kg−1·min−1 , 47.9 ± 6.3 and 50.0 ± 4.7 ml·kg−1·min−1 (12]). To date, only 2 studies (4,12) have investigated the relationship between V[Combining Dot Above]O2peak levels and surfing performance, both reporting that no significant relationship exists.
In addition to aerobic power, surf competitions demand a high anaerobic power when producing powerful strokes to position the board in the right location and gain enough momentum to catch waves (6,9,11). Anaerobic power has been assessed during maximal-intensity exercise using a swim bench ergometer on a variety of athlete populations (1,2,4,13–17). Literature on the use of ergometers to test swimmers and surfers' anaerobic power has established their reliability (5,13,17). Importantly, studies have also shown high correlations between swimming performance and power outputs obtained from swim bench ergometry testing (2,5,13,15,16), supporting the theory that swim bench power output is a potentially useful indicator of performance. However, only one study to date (5) has measured the power output of surfers using maximal-intensity paddling on a swim bench ergometer. Higher upper-body power outputs (348 ± 78 W) than that of other athletes, such as competitive swimmers (17) and surf lifesavers (13) (304 ± 22 and 326 ± 29 W, respectively), were reported suggesting that surfers possess comparatively high upper-body power outputs (5). Therefore, conceivably upper-body anaerobic fitness may be of importance to surfing competitors, however, to our knowledge, no study has reported the relationship between anaerobic power and surfing performance. Therefore, the purpose of this study was to first quantify the anaerobic and aerobic power characteristics of competitive surf athletes using a customized surf paddle–specific ergometer and thereafter determine the interrelationships between anaerobic power, aerobic capacity, and competitive surfing performance.
Experimental Approach to the Problem
The aerobic capacity and anaerobic power of nationally ranked surf athletes were determined over multiple testing occasions using a customized surf paddle–specific ergometer. Thereafter, the interrelationships between these components of physical performance and surfing performance, as assessed by season rank, were determined using correlation analysis.
Eight male (20.4 ± 6.6 years, 71.1 ± 11.2 kg, 181.4 ± 7.8 cm) national-level surfers volunteered to participate in an incremental V[Combining Dot Above]O2peak test and 20 male (23.3 ± 5.6 years, 72.8 ± 8.8 kg, 179.4 ± 6.8 cm) participated in a power test. The subjects who had a history of surfing at least 3 times per week and had competed for at least 3 years were tested during the final 2 events of the competitive season and the conclusion of the season. All the subjects were from the current top 35 ranked surfers in New Zealand and competing in the sanctioned New Zealand Surf Association competition. The subjects were tested following their normal routine of sleep, nutritional and hydration levels before testing. Ethics approval from the University Ethics Committee was gained before the commencement of the study, and written informed consent was obtained from each subject before commencing data collection.
A Dansprint kayak ergometer (Dansprint ApS, Denmark) was modified with a surfboard and hand paddles, similar to that of Mendez-Villanueva et al. (12), with subjects lying prone on a 6 ft. (1.8 m) by 0.48-m surfboard in an attempt to simulate a surfing-specific paddling action. Two 125-mm-wide and 210-mm-long hydro swim paddles with heavy duty velcro straps held the subjects' hands in place. The pulley cable ropes were attached to the middle of the velcro straps (Figures 1 and 2).
The ergometer was raised by 300 mm to ensure that none of the subjects touched the ground with the hand paddles. Additionally, the front of the ergometer was raised to 400 mm to simulate how the board would lie in the water when paddling (as the weight of the surfer weighs down the rear end of the board). Furthermore, this reduced the amount of lumbar hyperextension needed to paddle and hence was perceived as a more comfortable and natural paddle position. At the end of the ergometer, a board was attached for foot support. Raw data from the ergometer were exported into Microsoft Excel 2010 (©2010 Microsoft Corporation) for subsequent analysis.
For V[Combining Dot Above]O2peak assessments, a mixing-chamber metabolic analyzer was used (Metalyzer II, Cortex, Biophysik, Leipzig, Germany). The O2 and CO2 gas concentration analyzers and low-resistance turbine were calibrated before each test with alpha gases and air of known composition and volume, respectively. The subjects also wore a heart rate (HR) monitor (Polar T31, Polar Electro Oy, Kempele, Finland) fastened around the Sternum and T7-T9 Thoracic Vertebra, transmitting HR (5-second intervals) wirelessly to the short-range telemetry receiver (Polar 4000 Sport Tester, Polar Electro, Kempele, Finland) attached to the Metalyzer.
All physical data were collected in a temperature-controlled laboratory during and after specific sanctioned surf competitions. Specifically, the anaerobic power data were collected during 2 surf competitions (2 weeks apart). The V[Combining Dot Above]O2peak was collected 2 weeks after the conclusion of the competitive season. The dependent variable, surfing performance, was based on official season ranking from accumulated competition points.
Anaerobic Power Output Testing
The subjects were first familiarized with all the equipment and procedures. After a standardized warm-up (3 minutes of light-intensity 30-W continuous paddling combined with three 5-second maximal-intensity paddling efforts performed every minute separated by a 20-second rest) followed by a 10-minute rest, a countdown to start the subjects was given to perform a 10-second maximal-intensity effort. Average and peak power outputs (watts) and speed (kilometers per hour) per stroke were calculated via the Dansprint kayak ergometer software. The ergometer flywheel was set to the highest available resistance setting (10 out of 10) in an attempt to simulate water resistance (5).
Aerobic V[Combining Dot Above]O2peak Uptake Testing
The subjects performed a standardized warm-up paddle (1-minute incremental paddles starting at 20 W) of 5 minutes, followed by a 2-minute rest before initiating the test protocol. The flywheel was set at the lowest resistance level (1 out of 10) to avoid accelerated local muscular fatigue. The subjects then performed an incremental ramp test starting at 20 W during which power was increased by 5 W every minute until volitional exhaustion. The subjects were required to stay within ±5 W of the target power output throughout the test. Ventilation and expired gases were analyzed by the metabolic analyzer throughout the test. After completion, oxygen uptake (V[Combining Dot Above]O2) values were averaged over 30-second intervals with peak oxygen uptake (V[Combining Dot Above]O2peak) taken as the highest 30-second V[Combining Dot Above]O2 value.
Variables of interest recorded for subsequent analysis from the anaerobic power output test were anaerobic peak power: the maximal power output (watts) recorded during the 10-second paddle. Variables of interest recorded for subsequent analysis from V[Combining Dot Above]O2peak uptake testing were aerobic peak power (watts) and peak oxygen uptake (V[Combining Dot Above]O2peak).
Descriptive statistics throughout are presented as means and SDs to represent centrality and spread of data. Pearson's correlation coefficients were used to determine the interrelationships between variables of interest. Statistical significance was defined as p ≤ 0.05. Reliability of repeated measures of the anaerobic peak power assessment was determined with intraclass coefficients (ICCs).
Table 1 presents the mean (±SD) anaerobic power and V[Combining Dot Above]O2peak data. The ICC for 3 repeated anaerobic power tests was 0.97.
Table 2 presents the intercorrelation matrix between aerobic and anaerobic outputs and season rank. Rank obtained during the time of testing in competitive season significantly correlated with relative anaerobic peak power watts per kilogram (r = −0.50, p = 0.02), absolute anaerobic peak power (r = 0.55, p = 0.01) and mean anaerobic power (r = −0.57, p = 0.01). There were no significant correlations between any of the other measured variables and season rank. There were significant intercorrelations between absolute anaerobic power and peak aerobic power, and the aerobic V[Combining Dot Above]O2peak values (r = 0.87, p = 0.03, n = 6) (r = 0.78, p = 0.02), respectively. Figure 3 shows the relationship between the absolute peak anaerobic power output (n = 20) and season ranking.
Surfers frequently implement a burst of maximal-intensity paddling for several seconds to catch waves and a high-intensity paddle when padding out through breaking waves (6,8–11). Hence, the ability to produce power is conceivably important for competitive surfing athletes. The peak anaerobic power output achieved on the modified ergometer during the current study was 205 ± 54 W, lower than those recorded for maximal-paddling performance in other studies (5,17). However, we used a modified kayak ergometer rather than a swim bench ergometer adopted previously (5,17), thus possibly explaining the discrepancy. A novel finding from this study was the significant relationship between surfers season ranking and anaerobic peak power output (r = −0.50, p = 0.02). Although we acknowledge that correlations do not imply cause and effect and that the magnitude of the relationship is only moderate (although significant), it could be speculated that higher anaerobic power outputs allow more accomplished surfing athletes to catch some waves that their lower ranked counterparts might miss and therefore score higher. Such a finding provides theoretical support for the importance of anaerobic paddling power in assessment batteries and conditioning practice for surf athletes.
The V[Combining Dot Above]O2peak values observed in this study (44.0 ± 8.26 ml·kg−1·min−1) were similar to those reported in previous surfing studies (4,7,9,12) and comparable with those of other upper-body athletic populations measured in the prone position such as for swimmers (50–70 ml·kg−1·min−1) (3) and surf-life savers (40 ml·kg−1·min−1) (13). Given that aerobic fitness is considered a fundamental aspect of the sport (6,8,10,12), it was interesting that there was no significant correlation between the surfers' season ranking and relative V[Combining Dot Above]O2peak values (r = −0.02, p = 0.97). Although it is possible that low size confounded the statistical power, our findings are supported by those of other previous studies using similar sample sizes (4,7,9,12).
In this study, the peak aerobic power (watts) achieved during the incremental ramp test was 158 ± 21 W, similar to those reported by Mendez-Villanueva et al. (12) (155 ± 37 W) using similar protocols. In comparison, Loveless and Minahan (4) reported 199 ± 24 and 199 ± 44 W for competitive and recreational surfers, respectively. The difference (20.6%) between the findings of this study and those of Loveless and Minahan (4) may be owing to the differences in test protocols such as the increments used, equipment, and level of subjects' training experience. We found no significant correlation between peak aerobic power and season rank (r = −0.26, p = 0.54) suggesting that peak aerobic power is not a determinant of performance. In support, Loveless and Minahan (4) noted that peak aerobic power output did not differentiate between competitive and recreational surfers (t = 0.035, p = 0.97). However, Mendez-Villanueva et al. (12) reported that season rank significantly correlated with peak aerobic power output achieved during arm paddling (r = −0.67, p = 0.01). This could be owing to the difference in ramp protocol or may be associated with subjects being able to generate energy anaerobically at the later stages of the test or having improved exercise efficiency (4). Mendez-Villanueva et al. (12) did not report anaerobic peak power, so it is difficult to speculate on the influence of that on incremental peak aerobic power. Finally, we observed a significant correlation of (r = 0.87; p = 0.03; n = 6) between peak anaerobic power and peak aerobic power. Thus, strength and conditioning practitioners might find it expedient to test only aerobic power (incorporating the anaerobic power) given that the anaerobic test does not provide prognostic and diagnostic information of unique value. Although we acknowledge that correlations do not imply cause and effect, it does provide further theoretical support for the importance of paddling power.
Peak and mean anaerobic power can be quantified reliably, in the laboratory using a surf paddling–specific ergometry, to provide practitioners' insights into surfers' power outputs. We found no significant relationship between peak oxygen uptake and season rank, thus suggesting that peak oxygen uptake is not a defining measure of surfing ability. However, there was a significant relationship between surfers' season rank and peak anaerobic power. Although no significant correlation was observed between V[Combining Dot Above]O2peak and season performance, it may be contested that a certain level of aerobic capacity is still an important requisite for surfing performance given the generally reported moderate to high levels of aerobic fitness in surf athletes. It is unclear how peak power outputs measured during this study on a modified swim bench ergometer correlate with power generated when paddling on-water during surfing. Therefore, the development of a reliable and valid on-water assessment for anaerobic and aerobic outputs of surfers would be worthwhile. Future research should monitor the changes in anaerobic and aerobic outputs of surf-specific exercises and surf performance over a training intervention to better inform practitioners of assessment and conditioning priorities.
The application of the findings of this study should aid the strength and conditioning coach in creating training protocols designed to increase anaerobic power and endurance and aerobic endurance for surfing. Conceivably, improvements to maximal-paddling power output might improve surfing performance by allowing more powerful surf athletes to paddle and catch waves that lower ranked competitors miss. Therefore, assessment and conditioning practice should emphasize anaerobic power in a surf-specific swim paddle movement and should detail the loading parameters specific to surfing. Anaerobic power and endurance and cardiovascular endurance associated with physical performance in surfing could be developed through sport-specific and cross training.
The authors wish to acknowledge the involvement of Surfing New Zealand and gratitude to the surfers involved during the research and Scott Sinton for the photographs. No funding was received for this study, and there were no conflicts of interest.
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