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Physiological profiles of Australian surf boat rowers
Physiological Profiles of Australian Surf Boat Rowers James W Fell I & Philip T Gaffney 2 1Central Queensland University, Mackay, Queensland, Australia. 2Griffith University, Gold Coast, Queensland, Australia.
Fell, J.W., & Gaffney, P.T. (2001). Physiological profiles of Australian surfboat rowers. Journal of Science and Medicine in Sport 4 (2): 188-195. The physiological profiles of 17 open grade (OG) and 13 reserve grade (RG) male surfboat rowers (SBR) aged 19-44 years were determined and compared. Parameters investigated included anthropometryt agility, isometric strength, flexibility, rowing ergometer performance (MT), peak VO2 and arterialised blood pH, lactate and bicarbonate. Means were compared using t-tests. Multiple regression analyses provided a number of models for the prediction of MT performance in SBR. The mean age, height, mass, and sum of eight skinfolds for SBR are; 26.2 (+5.9) years, 180.5 (_+6.0) cm, 84.4 (_+9.3) kg and 78.2 (_+26.2) mm respectively. OG rowers were significantly different from RG for the parameters of ergometer performance (OG: 1360.2_+42.9 m; RG: 1316.4_+41.8 m), peak ventilation (OG: 174.2-+17.2 L.min-l; RG: 154.8_+22.1 L.min-l), and post exercise blood pH levels (OG: 6.98_+0.07; RG: 7.04-+0.07). Performance on a rowing ergometer successfully discriminates between OG and RG rowers with the best predictors of ergometer performance in SBR being height, peak ventilation, and post exercise pH.
introduction The physiological characteristics of internationally competitive rowers have previously b e e n well d o c u m e n t e d (Hagerman, 1984; Morton, Lawrence, B l a n k s b y & Bloomfield, 1984; Secher, 1993). However, in Australia there is a n o t h e r form of competitive rowing, s u r f b o a t rowing, w h i c h although similar, is also noticeably different. The sport of rowing s u r f b o a t s is as m u c h a part of Australian identity a n d culture as the image of S u r f Life Saving (SLS) in general. For a comprehensive history of SLS a n d s u r f b o a t rowing in Australia see Brown (1994) a n d Maxwell (1949). The sport requires crews of five rowers, one of w h o m steers the vessel, to negotiate the s u r f break, t u r n a r o u n d a b u o y 4 0 0 - 5 0 0 meters from the shore a n d return t h r o u g h the waves to the beach. Races take approximately five m i n u t e s to complete and include the categories of open, reserve, u n d e r 21, u n d e r 18, m a s t e r s and w o m e n (Surf Life Saving Australia, 1999). Depending on the event format, the n u m b e r of e n t r a n t s and the degree of a crew's success, t e a m s m a y complete one to ten races in a single day. Many crews follow d e m a n d i n g training regimes t h a t can involve u p to eleven sessions per week over eleven m o n t h s a year (Australian Sports Commission, 1995; Moseley, 1996). Training u s u a l l y involves weights, running, rowing and various forms of cross training. The intensity of these p r o g r a m s is often comparable to t h a t u n d e r t a k e n b y elite or Olympic level still water crews
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PhysiologicalProfiles of Australian Surf Boat Rowers
(Australian Sports Commission, 1995; Moseley, 1996). Most developments in the sport have occurred in equipment technology although this is limited by regulations imposed by SLS Australia. Unfortunately, there is a scarcity of information regarding the physiological requirements for surf boat rowers (SBR). Most information relating to SBR has come from trial and e r r o r and from research about still water rowing (Jorgensen, 1983a, Australian Sports Commission, 1995). Other literature available has addressed areas such as skills training (McLaren, 1992), crew selection (Jorgensen, 1983b), weight training (Crowe, 1994; McGaw, 1998), forces and interaction with technique (Hodgson, 1996), and epidemiology of injuries (Moseley, 1996). This investigation was undertaken to provide detailed physiological profiles of open and reserve grade SBR. The increasing level of professionalism in the sport and the exacting competition schedule emphasise the need for quantitative research on general physiological variables. This study has sought to determine the aerobic power, anthropometry, flexibility, strength, agility, performance on a rowing ergometer, as well as the blood lactate, bicarbonate and pH responses to exercise. The aim is to produce a body of data that will assist coaches and athletes in their development of training programs, selection of crews and talent identification in juniors as occurs in still water rowing (Hahn, 1989; Wenderoth et al., 1984). Comparison of crews competing at different levels may provide indications of the most important physiological parameters for success in this unique sport.
Methods Subjects Invitations to participate in the investigation were sent to all SLS clubs located on the Gold Coast - Australia. Thirty male SBR (aged 19-44 years) consented to participate in the study (17 open grade and 13 reserve grade). The tests were conducted within one month of the Australian National Titles to ensure that all participants were close to optimum seasonal condition. The subjects provided written informed consent prior to participation and the protocols used in the investigation had been approved by the Grfffith University H u m a n Ethics Committee. Procedures Participants undertook a series of tests during a single test session at Griffith University - Gold Coast. Tests included: anthropometric measurements (height, sitting height, mass, and sum of eight skinfolds using Harpenden skinfold calipers) according to protocols described in the Test Methods Manual (Draper,
Figure 1: The three rowing positions (catch, drive and finish) for measurement of isometric rowing strertgth.
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PhysiologicalProfiles of Australian Surf Boat Rowers
Minikin & Telford, 1991); a figure eight agility run (Schell & Leelarthaepin, 1990); the sit and reach test for flexibility (Wells & Dillon, 1952); isometric rowing strength (Secher, 1975) in the catch, drive and finish rowing positions (Figure 1); and a four minute 30 second 'maximal rowing ergometer test' (MT). Mahler, Andrea & Andreson, (1984) reported that in an 'all-out' rowing ergometer test of six minutes m a n y peak physiological values were obtained in the first two minutes of the test. Therefore, the MT was considered a valid test to elicit these variables and the best representation of a five-minute surfboat race where the last part of the race often involves catching a wave rather t h a n continued rowing. The MT was performed on the Concept IIC rowing ergometer (ERG) with performance in this test m e a s u r e d in metres rowed and m e a n watts produced. Subjects had arterialised capillary blood samples taken pre and one, three, five, seven and nine minutes post MT or until a peak in blood lactate concentration was observed. Blood lactate concentration was measured immediately using the Accusport® blood lactate analyser (Fell et al., 1998), Samples for pH and bicarbonate determination were stored in sealed heparinised capillary tubes between ice packs prior to assay using the Ciba Coming 865 Blood Gas Analyser@ (Gouget et al., 1990). Blood analysers were calibrated before each test according to manufacturer's guidelines. During the MT, expired respiratory gases were collected and analysed every fifteen seconds using the Quinton Metabolic Cart® (QMC). This instrument was calibrated prior to each test using samples of known volume and concentration. H e a r t rate (HR) was monitored t h r o u g h o u t the MT using the Q4500® electrocardiograph and a six-lead electrode configuration. Isometric rowing strength was m e a s u r e d using an isometric d y n a m o m e t e r (Lafayette®). The dynamometer used in this study was calibrated regularly and tested for linearity before and after the data collection up to the m a x i m u m range specified b y the m a n u f a c t u r e r (500kg). Statistical analyses The m e a n and standard deviation for all parameters m e a s u r e d were calculated for all subjects and for groups b a s e d on different competition levels (OG and RG). Comparisons between open and reserve grade rowers were m a d e using t-tests for differences between two groups. Pearson product m o m e n t correlations were also calculated, comparing m e a s u r e d performance on the ERG (metres and average watts) and all other parameters. The ten participating crews were ranked (1-10) according to their performances in various carnivals over the 1995-1996 season. Mean crew scores for p a r a m e t e r s investigated were then correlated against crew rank. Stepwise, forwards and backwards multiple linear regression analysis was carried out on the results to enable the generation of a predictive equation (Kleinbaum, Kupper & Muller, 1988) for ergometer performance dependant on physiological parameters. The combinations of the'variables that could best predict MT ergometer performance were determined. All statistical tests were performed using the SPSS® [V.7.5] (1996) computer software package. Significance was accepted at P= _<0.05.
ReSults Anthropometry Means and standard deviations for each of the anthropometric m e a s u r e s are disl~layed in Table 1. There were no significant differences between open and
190
Physiological Profiles of Australian Surf Boat Rowers
Parameter
Surf Boat Rowers Mean
Age (years)
26.2 (5.9)
Open Grade Mean
ReserveGrade Mean
Surf Life Savers# Mean
24.5 (3.2)
28.4 (7.9)
26.6 (6.6)
1.792 (0.054)
1.785 (0.083)
0.927 (0.034)
na
0.865 (0.035)
na
85.5 (10.9)
81.2 (11.5)
86.3 (29.2)
99.5 (49.0)
13.6 (5.8)
9.9 (8.3)
1880.0(176.1)
na
5.55 (0.55)
na
1316.4 (41.8)
na
333.8 (33.4)
na
184.1 (12.3)
196.5 (9.1)
4.4 (0.6)
4.52 (0.71)
51.5 (5.4)
56.3 (7.7)
154.8 (22.1)
na
1.9 (0.5)
na
15.4 (2.0)
12.4 (2.6)
24.4 (4.2)
na
8.2 (2.1)
na
7.374 (0.096)
na
7.042 (0.070)
na
P = 0.072
Height (m)
1.806 (0.060)
1.817 (0.063) P = 0.273
Sitting Height (m)
0.932 (0.029)
0.935 (0.026) P = 0.475
Length (m)
0.874 (0.040)
0.882 (0.043) P = 0.270
Mass (kg)
84.4 (9.3)
83.6 (8.t) P = 0.589
Skinfolds (ram)
78.2 (26.2)
71.9 (22.5) P = 0.139
Flexibility (cm)
12.8 (6.0)
12.1 (6.3) P = 0.495
Average isometric rowing strength (N) Agility (seconds)
1927.8 (154.3) 5.43 (0.44)
1962.6(129.4) P = 0.150 5.34 (0.32) P = 0.208
Ergometer Test Performance (m) Ergometer test average power (W) Peak heart rate (bpm)
1341.5 (47.2) 350.7 (37.1) 185 (9.8)
1360.2 (42.9)* P = O.021 358.6 (36.2) P = 0.075 185.5 (7.9) P =0.072
Peak VO2 (L.min1)
4.53 (0.56)
4.6 (0.6) P = 0.370
Peak ~/O2 (ml.kgl.min 1)
53.9 (5.5)
55.4 (6.0) P = 0.080
Peak ventilation (L.min-1) Pre lactate (mmol.r 1)
165.9 (20.9) 1.7 (0.5)
174.2 (17.2)* P=0.019 1.7 (0.5) P = 0.350
Post lactate (mmol.L"1)
15.5 (1.7)
15.5 (1.6) 0.818
Pre bicarbonate (mmol.l. 1)
23.8 (3.3)
23.4 (2.4) P = 0.454
Post bicarbonate (mmol.L~)
7.7 (1.7)
7.3 (1.2) P = 0.152
Pre pH
7.370 (0.082)
7.367 (0.073) P = 0.815
Post pH
7.005 (0.076)
6.978 (0.070)* P=0.022
(*open grade significantly different from reserve grade) Table 1:
Descriptive results for all measured parameters including mean and standard deviation (SD) for SBR in general as well as OG and RG rower means. Mean scores for surf life savers are also included for comparison #(Gulbin et al., 1996). (The results are taken from a previous study in the same laboratory.)
191
Physiological Profiles of Australian Surf Boat Rowers
Parameter Height Sitting Height Leg Length Mass Low pH Post MT Decrease in pH Peak ventilation Pre ~/02 (L.min1)
Metres Rowed
Average Watts MT
Metres Rowed (crew mean)
Crew Rank (crew mean)
0.82* 0.64* 0.75* 0.48 [0.009] -0.46 [0.014] 0.48 [0.011] 0.65* 0.71"
0.76* 0.51 [0.006] 0.76* 0.47 [0.011] ns 0.43 [0.022] 0.49 [0.014] 0.68*
0.87 [0.001] 0.81 [0.0041 0.88 [0.001] ns -0.83 [0.003] ns 0.81 [0.005] 0.87 [0.001]
ns ns ns ns 0.84 [0.0021 ns ns ns
* P
Table2:
Significant correlations with the performance measures of crew rank for the season, distance rowed and average watts on the Concept 11Crowing ergometer (r[P]).
reserve grade rowers for any of these parameters, although the mean age of reserve rowers was almost four years older than their open grade counterparts (mean [SD]; 28.4 [7.9] and 24.5 [3.2] years, respectively). Physiology
Most of the test results did not differentiate significantly between the OG and RG rowers (Table 1). There was a significant difference (p<0.05) between groups for the measures of metres rowed in the MT (OG: 1360.2+42.9 m; RG: 1316.4+_41.8 m), and post exercise blood pH levels (OG: 6.978+_0.070; RG: 7.042+_0.070). The OG rowers also demonstrated higher peak ventilation (174.2_+17.2 L.min- 1) during the MT than RG rowers (154.8_+22.1 L.min4). The Pearson product m o m e n t correlations (Table 2) identified several parameters that shared significant common variance with performance on the rowing ergometer, particularly height (r=0.76 to 0.87) and peak V02 in L.min -1 (r=0.68 to 0.87). Multiple regression analyses provided a number of models for the prediction of MT performance by SBR. The best models were obtained using backward elimination multiple regression. This identified the variables of height, peak ventilation, isometric rowing strength, post MT pH and bicarbonate levels, and peak VO2 (L.min-1) as the best predictors of MT performance (Table 3). Predictor Variables
Individual MT Performance
Height Isometric Strength • (finish postion) VO2 (Lmin "1) VE Post MT pH Post MT bicarbonate concentration
0.66 (P<0.001) 0.26 (P=0.002)
TOtal F Adjusted R square Table3:
192
0.33 (P<0.001)
63.9 0.90
Crew MT Performance
0.31 (P=0.045) 0.43 (P=~010) -0.64 (P=O.O02) 0.25 (P<0.001)
114.6 0.96
Backward elimination multiple regression analysis for prediction of surfboat rowing performance. (Valuesare significant standardised Beta coefficients).
Physiological Profiles of Australian Surf Boat Rowers
DiSCuSSiOn S u r f boat rowers are similar to other life savers {LS) for anthropometric and m a n y physiological parameters (Gulbin et al., 1996). The SBR do have a significantly lower m e a n s u b c u t a n e o u s body fat score t h a n IS. Differences were also evident for post exercise blood lactate and m a x i m u m heart rate. This m a y be a function of the different aerobic test used (incremental treadmill), although it should be noted that rowing ergometer and 'all out' tests s u c h as the MT are successful in eliciting VO2max. in trained rowers (Mahler et al., 1984; Stromme et al., 1977; Wilmore, 1984). The reasons for the differences between open and reserve grade rowers are not clear. Performance on the ERG is often used for training, testing and crew selection in both still water and s u r f boat rowing. In this study, the group difference in ERG performance is not due to differences in m e a s u r e s of aerobic fitness (peak ~ro2). It m a y be that the m e a s u r e s of post exercise pH and p e a k minute ventilation are the variables causing the difference in ERG performance. This might reflect the superior anaerobic capability of better rowers. Greater hydrogen ion accumulation from anaerobic metabolism m a y stimulate a n increased ventflatory response. Alternatively, the higher peak ventilation in OG rowers m a y be due to an entrainment of breathing during the rowing cycle. This entrainment h a s been reported in cycling (Garlando et al., 1985), and rowing (Grice et al., 1996; Mahler et al., 1991a; 1991b), and is linked with ability, expertise and efficiency. Success in s u r f boat rowing is determined by a crew rather t h a n an individual. Therefore, it m a y be more practical to m e a s u r e the m e a n physiological parameters of a crew. If the m e a n post exercise pH of a crew is correlated with season performance (Table 2), the relationship is highly significant (r=0.84; p<0.002). A stronger relationship between parameters is also evident if crew m e a n s rather t h a n individual scores are used for comparing post MT pH and metres rowed in the MT (r=-0.83; p<0.003). Several other correlations were strengthened when crew m e a n is used (Table 2) and this m a y emphasise the variability within crews. This study shows that ergometer performance is linked with success in s u r f boat rowing. Physiological parameters identified as contributing to ergometer performance by SBR have been identified by multiple regression analysis. The p a r a m e t e r s with the strongest influence are height, post MT pH and peak ventilation. The influence of height is substantial and probably reflects a biomechanical advantage for taller people on the ERG. Therefore, it is puzzling that there is no significant difference between OG and RG for height. The literature pertaining to still water rowers is comprehensive and emphasises the significance of variables s u c h as height, weight and aerobic fitness to success !Hahn, 1989; Secher, 1993). Secher et al., (1982) have shown a clear link between VO2max. and performance in rowing. The m e a n height (1.926 m), weight (89.6 kg), and skinfold thickness (50.2 mm), for elite Australian still water rowers (Hahn, 1989) are substantially different from that of SBR. This difference could be a result of a lesser degree of professionalism in SBR compared with still water rowers. Alternatively, it could suggest t h a t anthropometric variables and aerobic fitness contribute less to success when rowing in s u r f conditions. Success in s u r f boat rowing is multifaceted, and can be influenced by a changing s u r f environment, crew cohesiveness, equipment, and the experience of
193
PhysiologicalProfiles of Australian Surf Boat Rowers
the sweep rower. Crew selection can be influenced by factors s u c h as mateship or availability for training. This m a y lead to substantial variation in the ability of m e m b e r s of a crew. This investigation h a s provided the first detailed physiological profile of athletes from the sport of surfboat rowing. The results suggest the importance of anaerobic contributions to success in the sport. Better SBR outperform lower grade SBR in ergometer tests. During maximal exercise, the OG rowers can elicit higher minute ventilation t h a n RG rowers and can tolerate greater levels of blood acidosis. Multiple regression a n a l y s e s indicate the b e s t predictors of ergometer performance in SBR are height, peak ventilation, and post exercise pH. Consequently, training and crew selection m a y benefit from a focus on these parameters.
References Australian Sports Commission (1995). High Performance Training and Conditioning Handbook, Printatone. Rydalmere. Brown, J. (1994). The evolution of surf boats. Australian Surf Life Saver: Apr. pp.8-13. Crowe, J. {1994). Weight training for s u r f b o a t crews. Australian Surf Life Saver: Apr. pp.74-75. Draper, J., Minildn, B., & Telford, R. (Eds.) (1991). Test Methods Manual - Sports Specific Guidelines for Physiological A s s e s s m e n t of the Elite Athlete, Australian Sports Commission. Canberra. Fell, J. W., Rayfield, J. M., Gulbin, J. P., & Gaffney, P.T. (1998). Evaluation of the Aceusport® lactate analyser. The International Journal of Sports Medicine 19 (3}: 199-204. Garlando, F., Kohl, J., Koller, E. A., & Pietsch, P. (1985). Effect of coupling the breathing and cycling rhythms on oxygen uptake during bicycle ergometry. European Journal of Applied Physiology and Occupational P h y s i o l o g y 54: 497-501. Gouget, B., Gourmelin, Y., & Truchaud, A. (1990). Determination dn pH, de la pO 2 et de la pCO 2 a raide des electrodes sans maintenance du CIBA-CORNING 278 (Letter to the Editor). Ann. Biol Clin 48: 331-335. Grice, C., Sutton, I., Thompson, M., Smith, R., & Graham, K. (1996). Entrainment of breathing frequency to stroke rate in heavy weight male rowers, during maximal exercise tests on the rowing ergometer, at three different stroke rates. Proceedings of Australian Conference of Science and Medicine in Sport, Canberra, October, 28-31. Gulbin, J. P., Fell, J. W., & Gaffney, P. T. (1996). A physiological profile of elite surf ironmen, full time lifeguards & patrolling surf life savers. Australian J o u r n a l of Science & Medicine in Sport 28: 86-90. Hagerman, F. C. (1984). Applied physiology of rowing. Sports Medicine 1: 303-326. Hahn, A. (1989). Talent identification. In: Developing the elite athlete, (pp.3.1-3.6). Sydney, New South Wales Academy of Sport in association with Rothmans Foundation National Sport Division. High performance Coaches Workshop (Sydney, N.S.W.) Hodgson, K. (1996). Forces and interaction with technique in s u r f b o a t rowing. Surfcoach 1: 1619. Jorgenson, R. (1983a). Selecting a surf boat crew. Surfcoach 10: 6-8. Jorgenson, R. (1983b). Lessons from still water rowing. Surfcoach 11: 7-9. Kleinbaum D. G., Kupper, L. L., & Muller, K. E. (1988). Applied regression analysis and other multivariable m e t h o d s . Boston: PWS-KENT. Mahler, D. A., Andrea, B. E., & Andreson, D. C. {1984). Comparison of six minute "all out" and incremental exercise tests in elite oarsmen. Medicine and Science in Sports and Exercise 16 (6}: 567-571. Mahler, D. A., Hunter, B., Lentine, T., & Ward, J. (1991a). Locomotor - respiratory coupling develops in novice female rowers with training. Medicine and Science in Sports and Exercise 2 3 (12): 1362-1366. Mahler, D. A., Shuhart, C. R., Brew, E., & Stukel, T. A. (1991b). Ventilatory responses and entrainment of breathing during rowing. Medicine and Science in Sports and Exercise 2 3 (2): 186-192. Maxwell, C. B. (1949). Surf - Australians Against t h e Sea. Angus and Robertson. Sydney. McGaw, M. (1998). Ski and rowing training - weight regime. Australian Surf Lifesaver 29: 20-
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Physiological Profiles of Australian Surf Boat Rowers 22. McLaren, P. (1992). Skills training for novice surf boat rowers. Surfcoach (1): 3-8. Morton, A. R., Lawrence, S. R., Blanksby, B. A., & Bloomfield, J. (1984). A report of profiles of elite Australian oarsmen. Australian Rowing 7 (3): 21-23. Moseley, L. (1996). The incidence of injury in surfboat rowers. The Australian Journal of Science and Medicine in Sport 2 8 (4): 97-100. Schell, J., & Leelarthaepin, B. (1990). Physical Fitness A s s e s s m e n t in Exercise and Sport Science. Leelar Biomediscience Services: Matraville. Secher, N. (1975). Isometric rowing strength of experienced and inexperienced oarsmen. Medicine and Science in Sports 7 (4): 280-283. Secher, N. H. {1993). Physiological and biomechanical aspects of rowing-implications for training. Sports Medicine 15 (1): 24-42. Secher, N. H., Vaage, 0., & Jackson, R. C. (1982). Rowing performance and maximal aerobic power of oarsmen. Scandinavian J o u r n a l o f Sports Sciences 4: 9-11. SPSS (1996). Statistical Packages for the Social Sciences - Version 7.5, Chicago. Illinois. Stromme, S. B., Ingier, F., & Meen, H. D. (1977). Assessment of maximal aerobic power in specifically trained athletes. J o u r n a l of Applied Physiology 42: 833-37, Surf Life Saving Australia, (S.L.S.A.). (1999). Annual Report, NBX. Sydney. Wells, K., & Dillon, E. (1952). The sit and reach test: a test of back and leg flexibility. Research Quarterly 23: 115-118. Wenderoth, M. P., Snyder, A. C., & Steinrauf, L. K. (1984). Physiological testing: A case for its use in rowing. Rowing U.S.A. 16 (2): 17-18. Wilmore, J. (1984). The assessment of variation in aerobic power in world class athletes as related to specific sports, American J o u r n a l of Sports Medicine 12 {2}: 120-127.
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Fell, J.W., & Gaffney, P.T. (2001). Physiological profiles of Australian surfboat rowers. Journal of Science and Medicine in Sport 4 (2): 188-195. The physiological profiles of 17 open grade (OG) and 13 reserve grade (RG) male surfboat rowers (SBR) aged 19-44 years were determined and compared. Parameters investigated included anthropometryt agility, isometric strength, flexibility, rowing ergometer performance (MT), peak VO2 and arterialised blood pH, lactate and bicarbonate. Means were compared using t-tests. Multiple regression analyses provided a number of models for the prediction of MT performance in SBR. The mean age, height, mass, and sum of eight skinfolds for SBR are; 26.2 (+5.9) years, 180.5 (_+6.0) cm, 84.4 (_+9.3) kg and 78.2 (_+26.2) mm respectively. OG rowers were significantly different from RG for the parameters of ergometer performance (OG: 1360.2_+42.9 m; RG: 1316.4_+41.8 m), peak ventilation (OG: 174.2-+17.2 L.min-l; RG: 154.8_+22.1 L.min-l), and post exercise blood pH levels (OG: 6.98_+0.07; RG: 7.04-+0.07). Performance on a rowing ergometer successfully discriminates between OG and RG rowers with the best predictors of ergometer performance in SBR being height, peak ventilation, and post exercise pH.
introduction The physiological characteristics of internationally competitive rowers have previously b e e n well d o c u m e n t e d (Hagerman, 1984; Morton, Lawrence, B l a n k s b y & Bloomfield, 1984; Secher, 1993). However, in Australia there is a n o t h e r form of competitive rowing, s u r f b o a t rowing, w h i c h although similar, is also noticeably different. The sport of rowing s u r f b o a t s is as m u c h a part of Australian identity a n d culture as the image of S u r f Life Saving (SLS) in general. For a comprehensive history of SLS a n d s u r f b o a t rowing in Australia see Brown (1994) a n d Maxwell (1949). The sport requires crews of five rowers, one of w h o m steers the vessel, to negotiate the s u r f break, t u r n a r o u n d a b u o y 4 0 0 - 5 0 0 meters from the shore a n d return t h r o u g h the waves to the beach. Races take approximately five m i n u t e s to complete and include the categories of open, reserve, u n d e r 21, u n d e r 18, m a s t e r s and w o m e n (Surf Life Saving Australia, 1999). Depending on the event format, the n u m b e r of e n t r a n t s and the degree of a crew's success, t e a m s m a y complete one to ten races in a single day. Many crews follow d e m a n d i n g training regimes t h a t can involve u p to eleven sessions per week over eleven m o n t h s a year (Australian Sports Commission, 1995; Moseley, 1996). Training u s u a l l y involves weights, running, rowing and various forms of cross training. The intensity of these p r o g r a m s is often comparable to t h a t u n d e r t a k e n b y elite or Olympic level still water crews
188
PhysiologicalProfiles of Australian Surf Boat Rowers
(Australian Sports Commission, 1995; Moseley, 1996). Most developments in the sport have occurred in equipment technology although this is limited by regulations imposed by SLS Australia. Unfortunately, there is a scarcity of information regarding the physiological requirements for surf boat rowers (SBR). Most information relating to SBR has come from trial and e r r o r and from research about still water rowing (Jorgensen, 1983a, Australian Sports Commission, 1995). Other literature available has addressed areas such as skills training (McLaren, 1992), crew selection (Jorgensen, 1983b), weight training (Crowe, 1994; McGaw, 1998), forces and interaction with technique (Hodgson, 1996), and epidemiology of injuries (Moseley, 1996). This investigation was undertaken to provide detailed physiological profiles of open and reserve grade SBR. The increasing level of professionalism in the sport and the exacting competition schedule emphasise the need for quantitative research on general physiological variables. This study has sought to determine the aerobic power, anthropometry, flexibility, strength, agility, performance on a rowing ergometer, as well as the blood lactate, bicarbonate and pH responses to exercise. The aim is to produce a body of data that will assist coaches and athletes in their development of training programs, selection of crews and talent identification in juniors as occurs in still water rowing (Hahn, 1989; Wenderoth et al., 1984). Comparison of crews competing at different levels may provide indications of the most important physiological parameters for success in this unique sport.
Methods Subjects Invitations to participate in the investigation were sent to all SLS clubs located on the Gold Coast - Australia. Thirty male SBR (aged 19-44 years) consented to participate in the study (17 open grade and 13 reserve grade). The tests were conducted within one month of the Australian National Titles to ensure that all participants were close to optimum seasonal condition. The subjects provided written informed consent prior to participation and the protocols used in the investigation had been approved by the Grfffith University H u m a n Ethics Committee. Procedures Participants undertook a series of tests during a single test session at Griffith University - Gold Coast. Tests included: anthropometric measurements (height, sitting height, mass, and sum of eight skinfolds using Harpenden skinfold calipers) according to protocols described in the Test Methods Manual (Draper,
Figure 1: The three rowing positions (catch, drive and finish) for measurement of isometric rowing strertgth.
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PhysiologicalProfiles of Australian Surf Boat Rowers
Minikin & Telford, 1991); a figure eight agility run (Schell & Leelarthaepin, 1990); the sit and reach test for flexibility (Wells & Dillon, 1952); isometric rowing strength (Secher, 1975) in the catch, drive and finish rowing positions (Figure 1); and a four minute 30 second 'maximal rowing ergometer test' (MT). Mahler, Andrea & Andreson, (1984) reported that in an 'all-out' rowing ergometer test of six minutes m a n y peak physiological values were obtained in the first two minutes of the test. Therefore, the MT was considered a valid test to elicit these variables and the best representation of a five-minute surfboat race where the last part of the race often involves catching a wave rather t h a n continued rowing. The MT was performed on the Concept IIC rowing ergometer (ERG) with performance in this test m e a s u r e d in metres rowed and m e a n watts produced. Subjects had arterialised capillary blood samples taken pre and one, three, five, seven and nine minutes post MT or until a peak in blood lactate concentration was observed. Blood lactate concentration was measured immediately using the Accusport® blood lactate analyser (Fell et al., 1998), Samples for pH and bicarbonate determination were stored in sealed heparinised capillary tubes between ice packs prior to assay using the Ciba Coming 865 Blood Gas Analyser@ (Gouget et al., 1990). Blood analysers were calibrated before each test according to manufacturer's guidelines. During the MT, expired respiratory gases were collected and analysed every fifteen seconds using the Quinton Metabolic Cart® (QMC). This instrument was calibrated prior to each test using samples of known volume and concentration. H e a r t rate (HR) was monitored t h r o u g h o u t the MT using the Q4500® electrocardiograph and a six-lead electrode configuration. Isometric rowing strength was m e a s u r e d using an isometric d y n a m o m e t e r (Lafayette®). The dynamometer used in this study was calibrated regularly and tested for linearity before and after the data collection up to the m a x i m u m range specified b y the m a n u f a c t u r e r (500kg). Statistical analyses The m e a n and standard deviation for all parameters m e a s u r e d were calculated for all subjects and for groups b a s e d on different competition levels (OG and RG). Comparisons between open and reserve grade rowers were m a d e using t-tests for differences between two groups. Pearson product m o m e n t correlations were also calculated, comparing m e a s u r e d performance on the ERG (metres and average watts) and all other parameters. The ten participating crews were ranked (1-10) according to their performances in various carnivals over the 1995-1996 season. Mean crew scores for p a r a m e t e r s investigated were then correlated against crew rank. Stepwise, forwards and backwards multiple linear regression analysis was carried out on the results to enable the generation of a predictive equation (Kleinbaum, Kupper & Muller, 1988) for ergometer performance dependant on physiological parameters. The combinations of the'variables that could best predict MT ergometer performance were determined. All statistical tests were performed using the SPSS® [V.7.5] (1996) computer software package. Significance was accepted at P= _<0.05.
ReSults Anthropometry Means and standard deviations for each of the anthropometric m e a s u r e s are disl~layed in Table 1. There were no significant differences between open and
190
Physiological Profiles of Australian Surf Boat Rowers
Parameter
Surf Boat Rowers Mean
Age (years)
26.2 (5.9)
Open Grade Mean
ReserveGrade Mean
Surf Life Savers# Mean
24.5 (3.2)
28.4 (7.9)
26.6 (6.6)
1.792 (0.054)
1.785 (0.083)
0.927 (0.034)
na
0.865 (0.035)
na
85.5 (10.9)
81.2 (11.5)
86.3 (29.2)
99.5 (49.0)
13.6 (5.8)
9.9 (8.3)
1880.0(176.1)
na
5.55 (0.55)
na
1316.4 (41.8)
na
333.8 (33.4)
na
184.1 (12.3)
196.5 (9.1)
4.4 (0.6)
4.52 (0.71)
51.5 (5.4)
56.3 (7.7)
154.8 (22.1)
na
1.9 (0.5)
na
15.4 (2.0)
12.4 (2.6)
24.4 (4.2)
na
8.2 (2.1)
na
7.374 (0.096)
na
7.042 (0.070)
na
P = 0.072
Height (m)
1.806 (0.060)
1.817 (0.063) P = 0.273
Sitting Height (m)
0.932 (0.029)
0.935 (0.026) P = 0.475
Length (m)
0.874 (0.040)
0.882 (0.043) P = 0.270
Mass (kg)
84.4 (9.3)
83.6 (8.t) P = 0.589
Skinfolds (ram)
78.2 (26.2)
71.9 (22.5) P = 0.139
Flexibility (cm)
12.8 (6.0)
12.1 (6.3) P = 0.495
Average isometric rowing strength (N) Agility (seconds)
1927.8 (154.3) 5.43 (0.44)
1962.6(129.4) P = 0.150 5.34 (0.32) P = 0.208
Ergometer Test Performance (m) Ergometer test average power (W) Peak heart rate (bpm)
1341.5 (47.2) 350.7 (37.1) 185 (9.8)
1360.2 (42.9)* P = O.021 358.6 (36.2) P = 0.075 185.5 (7.9) P =0.072
Peak VO2 (L.min1)
4.53 (0.56)
4.6 (0.6) P = 0.370
Peak ~/O2 (ml.kgl.min 1)
53.9 (5.5)
55.4 (6.0) P = 0.080
Peak ventilation (L.min-1) Pre lactate (mmol.r 1)
165.9 (20.9) 1.7 (0.5)
174.2 (17.2)* P=0.019 1.7 (0.5) P = 0.350
Post lactate (mmol.L"1)
15.5 (1.7)
15.5 (1.6) 0.818
Pre bicarbonate (mmol.l. 1)
23.8 (3.3)
23.4 (2.4) P = 0.454
Post bicarbonate (mmol.L~)
7.7 (1.7)
7.3 (1.2) P = 0.152
Pre pH
7.370 (0.082)
7.367 (0.073) P = 0.815
Post pH
7.005 (0.076)
6.978 (0.070)* P=0.022
(*open grade significantly different from reserve grade) Table 1:
Descriptive results for all measured parameters including mean and standard deviation (SD) for SBR in general as well as OG and RG rower means. Mean scores for surf life savers are also included for comparison #(Gulbin et al., 1996). (The results are taken from a previous study in the same laboratory.)
191
Physiological Profiles of Australian Surf Boat Rowers
Parameter Height Sitting Height Leg Length Mass Low pH Post MT Decrease in pH Peak ventilation Pre ~/02 (L.min1)
Metres Rowed
Average Watts MT
Metres Rowed (crew mean)
Crew Rank (crew mean)
0.82* 0.64* 0.75* 0.48 [0.009] -0.46 [0.014] 0.48 [0.011] 0.65* 0.71"
0.76* 0.51 [0.006] 0.76* 0.47 [0.011] ns 0.43 [0.022] 0.49 [0.014] 0.68*
0.87 [0.001] 0.81 [0.0041 0.88 [0.001] ns -0.83 [0.003] ns 0.81 [0.005] 0.87 [0.001]
ns ns ns ns 0.84 [0.0021 ns ns ns
* P
Table2:
Significant correlations with the performance measures of crew rank for the season, distance rowed and average watts on the Concept 11Crowing ergometer (r[P]).
reserve grade rowers for any of these parameters, although the mean age of reserve rowers was almost four years older than their open grade counterparts (mean [SD]; 28.4 [7.9] and 24.5 [3.2] years, respectively). Physiology
Most of the test results did not differentiate significantly between the OG and RG rowers (Table 1). There was a significant difference (p<0.05) between groups for the measures of metres rowed in the MT (OG: 1360.2+42.9 m; RG: 1316.4+_41.8 m), and post exercise blood pH levels (OG: 6.978+_0.070; RG: 7.042+_0.070). The OG rowers also demonstrated higher peak ventilation (174.2_+17.2 L.min- 1) during the MT than RG rowers (154.8_+22.1 L.min4). The Pearson product m o m e n t correlations (Table 2) identified several parameters that shared significant common variance with performance on the rowing ergometer, particularly height (r=0.76 to 0.87) and peak V02 in L.min -1 (r=0.68 to 0.87). Multiple regression analyses provided a number of models for the prediction of MT performance by SBR. The best models were obtained using backward elimination multiple regression. This identified the variables of height, peak ventilation, isometric rowing strength, post MT pH and bicarbonate levels, and peak VO2 (L.min-1) as the best predictors of MT performance (Table 3). Predictor Variables
Individual MT Performance
Height Isometric Strength • (finish postion) VO2 (Lmin "1) VE Post MT pH Post MT bicarbonate concentration
0.66 (P<0.001) 0.26 (P=0.002)
TOtal F Adjusted R square Table3:
192
0.33 (P<0.001)
63.9 0.90
Crew MT Performance
0.31 (P=0.045) 0.43 (P=~010) -0.64 (P=O.O02) 0.25 (P<0.001)
114.6 0.96
Backward elimination multiple regression analysis for prediction of surfboat rowing performance. (Valuesare significant standardised Beta coefficients).
Physiological Profiles of Australian Surf Boat Rowers
DiSCuSSiOn S u r f boat rowers are similar to other life savers {LS) for anthropometric and m a n y physiological parameters (Gulbin et al., 1996). The SBR do have a significantly lower m e a n s u b c u t a n e o u s body fat score t h a n IS. Differences were also evident for post exercise blood lactate and m a x i m u m heart rate. This m a y be a function of the different aerobic test used (incremental treadmill), although it should be noted that rowing ergometer and 'all out' tests s u c h as the MT are successful in eliciting VO2max. in trained rowers (Mahler et al., 1984; Stromme et al., 1977; Wilmore, 1984). The reasons for the differences between open and reserve grade rowers are not clear. Performance on the ERG is often used for training, testing and crew selection in both still water and s u r f boat rowing. In this study, the group difference in ERG performance is not due to differences in m e a s u r e s of aerobic fitness (peak ~ro2). It m a y be that the m e a s u r e s of post exercise pH and p e a k minute ventilation are the variables causing the difference in ERG performance. This might reflect the superior anaerobic capability of better rowers. Greater hydrogen ion accumulation from anaerobic metabolism m a y stimulate a n increased ventflatory response. Alternatively, the higher peak ventilation in OG rowers m a y be due to an entrainment of breathing during the rowing cycle. This entrainment h a s been reported in cycling (Garlando et al., 1985), and rowing (Grice et al., 1996; Mahler et al., 1991a; 1991b), and is linked with ability, expertise and efficiency. Success in s u r f boat rowing is determined by a crew rather t h a n an individual. Therefore, it m a y be more practical to m e a s u r e the m e a n physiological parameters of a crew. If the m e a n post exercise pH of a crew is correlated with season performance (Table 2), the relationship is highly significant (r=0.84; p<0.002). A stronger relationship between parameters is also evident if crew m e a n s rather t h a n individual scores are used for comparing post MT pH and metres rowed in the MT (r=-0.83; p<0.003). Several other correlations were strengthened when crew m e a n is used (Table 2) and this m a y emphasise the variability within crews. This study shows that ergometer performance is linked with success in s u r f boat rowing. Physiological parameters identified as contributing to ergometer performance by SBR have been identified by multiple regression analysis. The p a r a m e t e r s with the strongest influence are height, post MT pH and peak ventilation. The influence of height is substantial and probably reflects a biomechanical advantage for taller people on the ERG. Therefore, it is puzzling that there is no significant difference between OG and RG for height. The literature pertaining to still water rowers is comprehensive and emphasises the significance of variables s u c h as height, weight and aerobic fitness to success !Hahn, 1989; Secher, 1993). Secher et al., (1982) have shown a clear link between VO2max. and performance in rowing. The m e a n height (1.926 m), weight (89.6 kg), and skinfold thickness (50.2 mm), for elite Australian still water rowers (Hahn, 1989) are substantially different from that of SBR. This difference could be a result of a lesser degree of professionalism in SBR compared with still water rowers. Alternatively, it could suggest t h a t anthropometric variables and aerobic fitness contribute less to success when rowing in s u r f conditions. Success in s u r f boat rowing is multifaceted, and can be influenced by a changing s u r f environment, crew cohesiveness, equipment, and the experience of
193
PhysiologicalProfiles of Australian Surf Boat Rowers
the sweep rower. Crew selection can be influenced by factors s u c h as mateship or availability for training. This m a y lead to substantial variation in the ability of m e m b e r s of a crew. This investigation h a s provided the first detailed physiological profile of athletes from the sport of surfboat rowing. The results suggest the importance of anaerobic contributions to success in the sport. Better SBR outperform lower grade SBR in ergometer tests. During maximal exercise, the OG rowers can elicit higher minute ventilation t h a n RG rowers and can tolerate greater levels of blood acidosis. Multiple regression a n a l y s e s indicate the b e s t predictors of ergometer performance in SBR are height, peak ventilation, and post exercise pH. Consequently, training and crew selection m a y benefit from a focus on these parameters.
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