This article was downloaded by: [Ohio State University Libraries] On: 27 February 2013, At: 14:39 Publisher: Routledge Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Journal of Sports Sciences Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/rjsp20
Peak treadmill running velocity during the VO2 max test predicts running performance a
a
T.D. Noakes , K.H. Myburgh & R. Schall
b
a
Liberty Life Chair of Exercise and Sports Science and MRC/UCT Bioenergetics of Exercise Research Unit, Department of Physiology, University of Cape Town Medical School, Observatory, 7925, South Africa b
Institute of Biostatistics of the Medical Research Council of South Africa, Tygerberg, 7505, South Africa Version of record first published: 01 Feb 2008.
To cite this article: T.D. Noakes , K.H. Myburgh & R. Schall (1990): Peak treadmill running velocity during the VO2 max test predicts running performance, Journal of Sports Sciences, 8:1, 35-45 To link to this article: http://dx.doi.org/10.1080/02640419008732129
PLEASE SCROLL DOWN FOR ARTICLE Full terms and conditions of use: http://www.tandfonline.com/page/terms-and-conditions This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae, and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand, or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.
Journal of Sports Sciences, 1990, 8, 35-45
Peak treadmill running velocity during the VO2 max test predicts running performance T.D. NOAKES1*, K.H. MYBURGH1 and R. SCHALL2
Downloaded by [Ohio State University Libraries] at 14:39 27 February 2013
l Liberty Life Chair of Exercise and Sports Science and MRC/UCT Bioenergetics of Exercise Research Unit, Department of Physiology, University of Cape Town Medical School, Observatory, 7925. South Africa 2 Institute of Biostatistics of the Medical Research Council of South Africa, Tygerberg, 7505, South Africa
Accepted 24 July 1989
Abstract Twenty specialist marathon runners and 23 specialist ultra-marathon runners underwent maximal exercise testing to determine the relative value of maximum oxygen consumption (VO2max), peak treadmill running velocity, running velocity at the lactate turnpoint, VO2 at 16 km h - 1 , % VO2max at 16 km h - 1 , and running time in other races, for predicting performance in races of 10-90 km. Race time at 10 or 21.1 km was the best predictor of performance at 42.2 km in specialist marathon runners and at 42.2 and 90 km in specialist ultra-marathon runners (r=0.91-0.97). Peak treadmill running velocity was the best laboratory-measured predictor of performance (r = - 0.88--0.94) at all distances in ultramarathon specialists and at all distances except 42.2 km in marathon specialists. Other predictive variables were running velocity at the lactate turnpoint (r= —0.80--0.92); % VO2max at 16 km h-1 (r=0.76-0.90) and VO2max (r=0.55--0.86). Peak blood lactate concentrations (r=0.68-0.71) and VO2 at 16 km h - 1 (r=0.10-0.61) were less good predictors. These data indicate: (i) that in groups of trained long distance runners, the physiological factors that determine success in races of 10-90 km are the same; thus there may not be variables that predict success uniquely in either 10 km, marathon or ultra-marathon runners, and (ii) that peak treadmill running velocity is at least as good a predictor of running performance as is the lactate turnpoint. Factors that determine the peak treadmill running velocity are not known but are not likely to be related to maximum rates of muscle oxygen utilization. Keywords: VO2max, lactate turnpoint, peak treadmill velocity; running performance, marathon, ultra-marathon.
Introduction Interest in physiological factors that determine athletic performance can be traced to studies first performed at the turn of the century (Noakes, 1988). These and other early studies showed that the peak rates of oxygen consumption (K) 2 max) expressed relative to body weight were highest in the best endurance athletes (Astrand, 1955; Herbst, 1928; Robinson et al,. 1937). Subsequent studies led to the conclusion that FO 2 max was the most important determinant of *To whom correspondence should be addressed. 0264-0414/90 $03.00 + .12 © 1990 E. & F.N. Spon Ltd.
Downloaded by [Ohio State University Libraries] at 14:39 27 February 2013
36
Noakes, Myburgh and Schall
potential'for endurance sports (Costill, 1967; Costill et al, 1973; Foster, 1983; Foster et al, 1977; Leary and Wyndam, 1965; Saltin and Astrand 1967; Wyndham et al., 1969). However, more modern studies indicate that ^O2max is a weaker predictor of performance and other variables including running economy (Conley and Krahenbuhl, 1980; LaFontaine et al., 1981; Sjodin and Schele, 1982), the blood lactate turapoint (Farrell et al, 1979; Fohrenbach et al, 1987; Sjodin and Jacobs, 1981; Sjodin and Schele, 1982; Sjodin and Svedenhag, 1985; Tanaka and Matsuura, 1984; Tanaka et al, 1983; Yoshida et al, 1987) and the ventilation threshold (Kumagai et al, 1982; Powers et al, 1983; Rhodes and McKenzie, 1984; Tanaka et al, 1983; Tanaka et al, 1984; Tanaka et al, 1986) may be superior predictors of running performance. In a previous study from this laboratory, we found that in a group of runners homogenous for KO2max but not for running performance, the peak treadmill runnning velocity reached during the FO2max test was a better predictor of running performance at all distances from 10-90 km than was the FO2max (Scrimgeour et al, 1986). Furthermore we noted a relationship between peak treadmill running velocity and running economy; those athletes who reached the highest treadmill running velocities were also the most economical. To extend that study, we chose to compare the relative predictive power of a comprehensive battery of physiological variables including J^O2max, peak treadmill running velocity, running economy and the running velocity at the blood lactate turnpoint for running performance at distances from 10-90 km, in a large group of trained runners specializing either at the marathon or ultra-marathon distance. Only three previous studies have included peak treadmill running velocity (Morgan et al, 1986; Tanaka et al, 1984) or a derivative (Daniels et al, 1986) as a possible predictor of running performance and none have measured all these variables in specialist ultra-marathon runners. Materials and methods
Forty three subjects were recruited for this study. All were experienced runners who were studied whilst training specifically for marathon or longer distance races. They reported to the laboratory on two separate occasions after a 3 h fast. Prior to testing they were weighed on an electronic scale (Vogel and Halke, Hamburg, West Germany). They then completed a standardized questionnaire of their training methods and their best times in races of 10-90 km within a 3 month period of being tested. On the first testing day, the subjects underwent a progressive maximal treadmill test to exhaustion by methods previously described (Matter et al, 1987; Scrimgeour et al, 1986). After a 5 min warm-up run, a Jelco intravenous catheter placement unit (Critikon; Tampa, Fl, USA) was inserted into a subcutaneous forearm vein and connected via pre-heparinized tubing to a Eyela Microtube Pump MP-3 (Rikakikai Co. Ltd, Tokyo, Japan). The pump drew blood continuously at a rate of 2 ml min" 1 . From 15-45 s of each minute of the test, 1 ml of blood was collected into tubes containing 2 ml of ice-cold 70% perchloric acid for later analysis of blood lactate concentrations as previously described (Matter et al, 1987). Subjects began exercising at 10 km h ~1 with incremental increases of 1 km h ~1 every minute until exhaustion. On the second visit to the laboratory, subjects ran for 6 min at each of three submaximal running speeds chosen according to their athletic ability. In general, the intermediate running speed was chosen to approximate the athlete's average running speed in races of 42.2 km; the other speeds being 1.5 km h" 1 faster and slower than that speed. The calibration of the treadmill speed was verified daily with a Smith tachometer.
Predicting running performance
37
Downloaded by [Ohio State University Libraries] at 14:39 27 February 2013
Calculation and expression of results
The ^O2max was taken as the highest rate of oxygen consumption measured during any 60 s (Noakes, 1988). During treadmill testing expired air was continuously sampled and the rates of oxygen consumption (J^Oj), carbon dioxide production (^CO2) and respiratory exchange ratio (RER) were calculated every 3 s by an on-line computer (Apple) using software (ART) based on conventional equations (Matter et al., 1987; Scrimgeour et al., 1986). The average value for each minute for each parameter was stored for later printing. Peak treadmill running velocity was taken as the highest speed (km h~ *) maintained for a complete minute during the maximal test. When an athlete was unable to complete 60 s at a particular treadmill velocity, the velocity of the immediately preceeding, completed work stage was recorded as the peak treadmill running velocity. The mean oxygen consumption during the last 3 min of each run at the submaximal running speed was used to draw individual graphs of oxygen consumption at the different running speeds. These graphs were used to determine an oxygen cost at one submaximal running speed (16 km h" 1 ) for determination of running economy. Individual graphs of venous blood lactate concentrations at different running speeds were drawn. Recent findings indicate that during progressive exercise, blood lactate concentrations increase as a continous function rather than as a threshold phenomenon (Hughson et al, 1987). In this study, the blood lactate turnpoint was determined visually as previously (Matter et ah, 1987) and expressed as the treadmill velocity (km h~ *) corresponding to the last blood lactate concentration that immediately preceded the rapid and progressive increase in blood lactate levels. This point corresponds to the anaerobic threshold (Xt) of the lactate threshold model (Figure 1 in Hughson et al., 1987). This treadmill velocity was also expressed as a percentage of the peak treadmill running velocity. The blood lactate concentration at the lactate turnpoint was also recorded. The highest blood lactate concentration measured during the first 5 min of recovery was recorded as the peak blood lactate concentration.
Statistical methods Means and standard deviations for each variable were calculated by conventional formulae (Snedecor and Cochran, 1980). Thereafter, linear correlations were performed to correlate physiological and performance variables with performance at distances between 10 and 90 km. The correlation coefficient between each pair of variables is reported and a t-test was performed to determine the statistical significance of each correlation (Snedecor and Cochran, 1980). In addition multiple linear regression was performed using the all subsets routine BMDP9R (Dixon, 1985), to select the best independent variables to predict performance time at 10,21.1 and 42.2 km in the total group of runners and in the sub-groups of specialist marathon and ultra-marathon runners. In addition the variables predicting performance in the 90 km ultramarathon in specialist ultramarathon runners were also determined. The best subset of independent variables was selected according to the smallest Mallow's Cp-criterion (Weisberg, 1980). The subset with the smallest Cp minimizes the mean squared error of prediction (Weisberg, 1980).
38
Noakes, Myburgh and Schall
Downloaded by [Ohio State University Libraries] at 14:39 27 February 2013
Results
Table 1 lists the physiological and performance characteristics of the 43 runners. As a group they were of above-average running ability (mean+S.D. 10 km time of 35.0+3.9 min) with a relatively high mean FO2max of 66.2 + 8.0 ml O 2 kg" 1 min" 1 . Race times at 10,21.1 and 42.2 km of the specialist marathon runners were faster than those of the specialist ultramarathon runners, although only the 10 km time differed significantly (P
Journal of Sports Sciences Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/rjsp20
Peak treadmill running velocity during the VO2 max test predicts running performance a
a
T.D. Noakes , K.H. Myburgh & R. Schall
b
a
Liberty Life Chair of Exercise and Sports Science and MRC/UCT Bioenergetics of Exercise Research Unit, Department of Physiology, University of Cape Town Medical School, Observatory, 7925, South Africa b
Institute of Biostatistics of the Medical Research Council of South Africa, Tygerberg, 7505, South Africa Version of record first published: 01 Feb 2008.
To cite this article: T.D. Noakes , K.H. Myburgh & R. Schall (1990): Peak treadmill running velocity during the VO2 max test predicts running performance, Journal of Sports Sciences, 8:1, 35-45 To link to this article: http://dx.doi.org/10.1080/02640419008732129
PLEASE SCROLL DOWN FOR ARTICLE Full terms and conditions of use: http://www.tandfonline.com/page/terms-and-conditions This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae, and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand, or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.
Journal of Sports Sciences, 1990, 8, 35-45
Peak treadmill running velocity during the VO2 max test predicts running performance T.D. NOAKES1*, K.H. MYBURGH1 and R. SCHALL2
Downloaded by [Ohio State University Libraries] at 14:39 27 February 2013
l Liberty Life Chair of Exercise and Sports Science and MRC/UCT Bioenergetics of Exercise Research Unit, Department of Physiology, University of Cape Town Medical School, Observatory, 7925. South Africa 2 Institute of Biostatistics of the Medical Research Council of South Africa, Tygerberg, 7505, South Africa
Accepted 24 July 1989
Abstract Twenty specialist marathon runners and 23 specialist ultra-marathon runners underwent maximal exercise testing to determine the relative value of maximum oxygen consumption (VO2max), peak treadmill running velocity, running velocity at the lactate turnpoint, VO2 at 16 km h - 1 , % VO2max at 16 km h - 1 , and running time in other races, for predicting performance in races of 10-90 km. Race time at 10 or 21.1 km was the best predictor of performance at 42.2 km in specialist marathon runners and at 42.2 and 90 km in specialist ultra-marathon runners (r=0.91-0.97). Peak treadmill running velocity was the best laboratory-measured predictor of performance (r = - 0.88--0.94) at all distances in ultramarathon specialists and at all distances except 42.2 km in marathon specialists. Other predictive variables were running velocity at the lactate turnpoint (r= —0.80--0.92); % VO2max at 16 km h-1 (r=0.76-0.90) and VO2max (r=0.55--0.86). Peak blood lactate concentrations (r=0.68-0.71) and VO2 at 16 km h - 1 (r=0.10-0.61) were less good predictors. These data indicate: (i) that in groups of trained long distance runners, the physiological factors that determine success in races of 10-90 km are the same; thus there may not be variables that predict success uniquely in either 10 km, marathon or ultra-marathon runners, and (ii) that peak treadmill running velocity is at least as good a predictor of running performance as is the lactate turnpoint. Factors that determine the peak treadmill running velocity are not known but are not likely to be related to maximum rates of muscle oxygen utilization. Keywords: VO2max, lactate turnpoint, peak treadmill velocity; running performance, marathon, ultra-marathon.
Introduction Interest in physiological factors that determine athletic performance can be traced to studies first performed at the turn of the century (Noakes, 1988). These and other early studies showed that the peak rates of oxygen consumption (K) 2 max) expressed relative to body weight were highest in the best endurance athletes (Astrand, 1955; Herbst, 1928; Robinson et al,. 1937). Subsequent studies led to the conclusion that FO 2 max was the most important determinant of *To whom correspondence should be addressed. 0264-0414/90 $03.00 + .12 © 1990 E. & F.N. Spon Ltd.
Downloaded by [Ohio State University Libraries] at 14:39 27 February 2013
36
Noakes, Myburgh and Schall
potential'for endurance sports (Costill, 1967; Costill et al, 1973; Foster, 1983; Foster et al, 1977; Leary and Wyndam, 1965; Saltin and Astrand 1967; Wyndham et al., 1969). However, more modern studies indicate that ^O2max is a weaker predictor of performance and other variables including running economy (Conley and Krahenbuhl, 1980; LaFontaine et al., 1981; Sjodin and Schele, 1982), the blood lactate turapoint (Farrell et al, 1979; Fohrenbach et al, 1987; Sjodin and Jacobs, 1981; Sjodin and Schele, 1982; Sjodin and Svedenhag, 1985; Tanaka and Matsuura, 1984; Tanaka et al, 1983; Yoshida et al, 1987) and the ventilation threshold (Kumagai et al, 1982; Powers et al, 1983; Rhodes and McKenzie, 1984; Tanaka et al, 1983; Tanaka et al, 1984; Tanaka et al, 1986) may be superior predictors of running performance. In a previous study from this laboratory, we found that in a group of runners homogenous for KO2max but not for running performance, the peak treadmill runnning velocity reached during the FO2max test was a better predictor of running performance at all distances from 10-90 km than was the FO2max (Scrimgeour et al, 1986). Furthermore we noted a relationship between peak treadmill running velocity and running economy; those athletes who reached the highest treadmill running velocities were also the most economical. To extend that study, we chose to compare the relative predictive power of a comprehensive battery of physiological variables including J^O2max, peak treadmill running velocity, running economy and the running velocity at the blood lactate turnpoint for running performance at distances from 10-90 km, in a large group of trained runners specializing either at the marathon or ultra-marathon distance. Only three previous studies have included peak treadmill running velocity (Morgan et al, 1986; Tanaka et al, 1984) or a derivative (Daniels et al, 1986) as a possible predictor of running performance and none have measured all these variables in specialist ultra-marathon runners. Materials and methods
Forty three subjects were recruited for this study. All were experienced runners who were studied whilst training specifically for marathon or longer distance races. They reported to the laboratory on two separate occasions after a 3 h fast. Prior to testing they were weighed on an electronic scale (Vogel and Halke, Hamburg, West Germany). They then completed a standardized questionnaire of their training methods and their best times in races of 10-90 km within a 3 month period of being tested. On the first testing day, the subjects underwent a progressive maximal treadmill test to exhaustion by methods previously described (Matter et al, 1987; Scrimgeour et al, 1986). After a 5 min warm-up run, a Jelco intravenous catheter placement unit (Critikon; Tampa, Fl, USA) was inserted into a subcutaneous forearm vein and connected via pre-heparinized tubing to a Eyela Microtube Pump MP-3 (Rikakikai Co. Ltd, Tokyo, Japan). The pump drew blood continuously at a rate of 2 ml min" 1 . From 15-45 s of each minute of the test, 1 ml of blood was collected into tubes containing 2 ml of ice-cold 70% perchloric acid for later analysis of blood lactate concentrations as previously described (Matter et al, 1987). Subjects began exercising at 10 km h ~1 with incremental increases of 1 km h ~1 every minute until exhaustion. On the second visit to the laboratory, subjects ran for 6 min at each of three submaximal running speeds chosen according to their athletic ability. In general, the intermediate running speed was chosen to approximate the athlete's average running speed in races of 42.2 km; the other speeds being 1.5 km h" 1 faster and slower than that speed. The calibration of the treadmill speed was verified daily with a Smith tachometer.
Predicting running performance
37
Downloaded by [Ohio State University Libraries] at 14:39 27 February 2013
Calculation and expression of results
The ^O2max was taken as the highest rate of oxygen consumption measured during any 60 s (Noakes, 1988). During treadmill testing expired air was continuously sampled and the rates of oxygen consumption (J^Oj), carbon dioxide production (^CO2) and respiratory exchange ratio (RER) were calculated every 3 s by an on-line computer (Apple) using software (ART) based on conventional equations (Matter et al., 1987; Scrimgeour et al., 1986). The average value for each minute for each parameter was stored for later printing. Peak treadmill running velocity was taken as the highest speed (km h~ *) maintained for a complete minute during the maximal test. When an athlete was unable to complete 60 s at a particular treadmill velocity, the velocity of the immediately preceeding, completed work stage was recorded as the peak treadmill running velocity. The mean oxygen consumption during the last 3 min of each run at the submaximal running speed was used to draw individual graphs of oxygen consumption at the different running speeds. These graphs were used to determine an oxygen cost at one submaximal running speed (16 km h" 1 ) for determination of running economy. Individual graphs of venous blood lactate concentrations at different running speeds were drawn. Recent findings indicate that during progressive exercise, blood lactate concentrations increase as a continous function rather than as a threshold phenomenon (Hughson et al, 1987). In this study, the blood lactate turnpoint was determined visually as previously (Matter et ah, 1987) and expressed as the treadmill velocity (km h~ *) corresponding to the last blood lactate concentration that immediately preceded the rapid and progressive increase in blood lactate levels. This point corresponds to the anaerobic threshold (Xt) of the lactate threshold model (Figure 1 in Hughson et al., 1987). This treadmill velocity was also expressed as a percentage of the peak treadmill running velocity. The blood lactate concentration at the lactate turnpoint was also recorded. The highest blood lactate concentration measured during the first 5 min of recovery was recorded as the peak blood lactate concentration.
Statistical methods Means and standard deviations for each variable were calculated by conventional formulae (Snedecor and Cochran, 1980). Thereafter, linear correlations were performed to correlate physiological and performance variables with performance at distances between 10 and 90 km. The correlation coefficient between each pair of variables is reported and a t-test was performed to determine the statistical significance of each correlation (Snedecor and Cochran, 1980). In addition multiple linear regression was performed using the all subsets routine BMDP9R (Dixon, 1985), to select the best independent variables to predict performance time at 10,21.1 and 42.2 km in the total group of runners and in the sub-groups of specialist marathon and ultra-marathon runners. In addition the variables predicting performance in the 90 km ultramarathon in specialist ultramarathon runners were also determined. The best subset of independent variables was selected according to the smallest Mallow's Cp-criterion (Weisberg, 1980). The subset with the smallest Cp minimizes the mean squared error of prediction (Weisberg, 1980).
38
Noakes, Myburgh and Schall
Downloaded by [Ohio State University Libraries] at 14:39 27 February 2013
Results
Table 1 lists the physiological and performance characteristics of the 43 runners. As a group they were of above-average running ability (mean+S.D. 10 km time of 35.0+3.9 min) with a relatively high mean FO2max of 66.2 + 8.0 ml O 2 kg" 1 min" 1 . Race times at 10,21.1 and 42.2 km of the specialist marathon runners were faster than those of the specialist ultramarathon runners, although only the 10 km time differed significantly (P
