Training & Testing
729
Evaluation of the Best-designed Graded Exercise Test to Assess Peak Treadmill Speed
Authors
C. S. Peserico1, A. M. Zagatto2, F. A. Machado1
Affiliations
1
Key words ▶ physical endurance ● ▶ running ● ▶ exercise test ● ▶ athletic performance ● ▶ sports physiology ●
Abstract
Department of Physical Education, State University of Maringá, Maringá, Brazil Department of Physical Education, Sao Paulo State University, Bauru, Brazil
▼
This study examined the influence of different speed increments during treadmill exercise tests on peak treadmill speed (Vpeak) and its relationship with a 1-h treadmill running performance. 18 male recreational and amateur runners (10km running pace: 10–15 km · h − 1) performed, in an alternate order, 3 continuous incremental exercise tests with different speed increments (0.5, 1.0 and 2.0 km · h − 1) on a motorized treadmill to determine Vpeak. Thereafter they undertook a 1-h time trial on a treadmill. Vpeak was determined as either (a) the highest speed that could be maintained for a complete minute (Vpeak-60 s), (b) the speed of the last complete
Introduction
▼
accepted after revision January 21, 2015 Bibliography DOI http://dx.doi.org/ 10.1055/s-0035-1547225 Published online: April 14, 2015 Int J Sports Med 2015; 36: 729–734 © Georg Thieme Verlag KG Stuttgart · New York ISSN 0172-4622 Correspondence Fabiana Andrade Machado Department of Physical Education State University of Maringá Av. Colombo, 5790 87.020-900, Maringá Brazil Tel.: + 55/44/3011 4315 Fax: + 55/44/3011 4470 [email protected]
The peak treadmill speed obtained during an incremental exercise test (Vpeak) is a good predictor of endurance performance in runners [10, 14, 22] and can be determined without the use of expensive metabolic equipment or invasive techniques [20]. However, the design of an incremental test can affect the responses of Vpeak and its relationship with endurance running performance [2, 10]. Machado et al. [10] recently showed that incremental treadmill tests comprising 3-min stage duration were preferred to 1-min and 2-min stage duration protocols in order to determine Vpeak to accurately predict 5-km and 10-km running performances. However, this is a unique study, and the influences of speed increments during treadmill exercise tests on Vpeak and its relationship with endurance running performance remain unknown. Sports scientists and coaches generally use a wide range of speed increment during incremental exercise tests. However, the test design may
stage (Vpeak-C), or (c) the speed of the last complete stage added to the product of the speed increment and the completed fraction of the incomplete stage (Vpeak-P). The Vpeak values were highly influenced by the different speed-incremented rates and the Vpeak-P determined during the protocol comprising speed increments of 1 km · h − 1 presented the highest correlation with 1-h time trial performance (r = 0.89). The results suggest that a protocol with speed increments comprising 1 km · h − 1 and with a 3-min stage duration should be used as standard for the determination of Vpeak to assess aerobic fitness and predict endurance performance in recreational runners. Furthermore, the Vpeak-P should be used for the determination of Vpeak.
influence the Vpeak and consequently may change the validity of using it for predicting performance and monitoring training [2]. Thus it is important to elucidate the effects of speed increments during treadmill exercise tests on Vpeak and its relationship with endurance running performance. The major shortcoming of the study from Machado et al. [10] was that the running performances were determined on a 400-m outdoor running track, unsheltered from environmental conditions. Alterations in these variables could have affected the associations between Vpeak and endurance running performance. Thus, selfpaced running performances under laboratory conditions involving the use of a motorized treadmill could avoid this shortcoming. Machado et al. [10] also compared 3 Vpeak values, determined from different criteria, and examined their relationship with performance. They concluded that, independent of the stage duration, the Vpeak as defined according to Kuipers et al. [8] criterion provided the highest correlation with running performances, and should be used as a standard for the determination of Vpeak.
Peserico CS et al. Evaluation of the Best-designed … Int J Sports Med 2015; 36: 729–734
Downloaded by: Rutgers University. Copyrighted material.
2
730 Training & Testing
Methods
▼
Participants
18 male recreational and amateur runners with experience in 10-km running races and involved in systematic training volunteered to participate in this study. Characteristics of the participants (mean ± SD) were: age 25.5 ± 3.3 years, height 178.0 ± 7.0 cm, body mass 76.2 ± 8.6 kg, body mass index (BMI) 24.1 ± 2.3 kg · m − 2 and body fat 13.9 ± 3.0 %. The training characteristics were experience 3.8 ± 3.3 years, frequency 3.2 ± 1.1 days · wk − 1 and distance 27.4 ± 17.0 km · wk − 1. The 10-km running times of the participants were between 40 and 60 min, with a pace between 10 and 15 km · h − 1 (≅ 44–66 % of the world record). Prior to testing, written informed consent was obtained from all participants. The experimental protocol was approved by the local ethics committee (#719/2010). All research was conducted ethically according to international standards and as required by the International Journal of Sports Medicine [6].
Experimental design
Participants who were accustomed to treadmill running tests performed 3 continuous incremental exercise tests with different speed increments on a motorized treadmill (Super ATL; Inbrasport, Porto Alegre, Brazil), with the gradient set at 1 %, to determine Vpeak that is a reliable and accurate measure [15]. First, participants performed each of the 3 protocols in an alternate order. Thereafter, each participant performed the 3 tests again, maintaining the same order as before. The 3 incremental protocols were as follows: (a) low-increment protocol with increments of 0.5 km · h − 1, (b) intermediate-increment protocol with increments of 1 km · h − 1, and (c) high-increment protocol with increments of 2 km · h − 1. The 6 incremental tests were performed over 3 weeks, with each test separated from the other by at least 72 h. The better of 2 performances for each participant during each protocol was recorded and used in the results. Thereafter, within a 7-day period after the incremental tests, the participants undertook a 1-h time trial under laboratory conditions, in which the participants ran as far as possible on a motorized treadmill by setting their own pace throughout the test [19]. 1-h time trial treadmill performance is a reliable test with a coefficient of variation (CV) generally below 3 % [17, 19]. Participants were instructed to report for testing well-rested, wellnourished, and well-hydrated, wearing lightweight comfortable clothing. Participants were also instructed to avoid eating 2 h before the tests, to abstain from caffeine and alcohol, and to refrain from the training routines during testing.
Incremental exercise protocols
After a warm-up that consisted of walking at 6 km · h − 1 for 3 min, each protocol started with an initial treadmill speed of 8 km · h − 1, followed by an increase of 0.5 km · h − 1, 1 km · h − 1 or 2 km · h − 1 between each successive stage of 3 min until participants reached their volitional exhaustion. Consistently across each trial, participants were strongly encouraged, verbally, to invest maximum effort. The tests were performed in the morning, at the same time of the day, under normal laboratory conditions (temperature = 20–22 °C and relative humidity = 50–60 %).
Psychophysiological and physiological variables
Before testing, participants were familiarized with the 6-20 Borg scale [3] which was used to measure the rating of perceived exertion (RPE) during the last 15 s of each stage and at exhaustion. The highest RPE value was adopted as the peak RPE (RPEpeak). The HR was recorded every 5 s throughout the tests (Polar RS800SD, Kempele, Finland) and the maximal heart rate (HRmax) was defined as the highest HR value recorded during the tests [23]. Neither respiratory gases nor blood lactate was monitored during the tests given that such interventions could impair the performance of the participants [19]. Earlobe capillary blood samples (25 µL) were collected into a capillary tube after the end of each test, at the fifth minute of passive recovery, sitting in a comfortable chair. From these samples, blood lactate concentration was subsequently determined by electroenzymatic methods using an automated analyzer (YSI 2300 STAT, Ohio, USA) for the determination of peak blood lactate concentration (LApeak) post-exercise. The maximal effort was deemed to be achieved if the incremental test met 2 of the following criteria: 1) LApeak ≥ 8 mmol · L − 1, 2) HRmax ≥ 95 % of endurance-trained age-predicted maximum heart rate (APMHR) using the age-based (206– 0.7 × age) equation [23] and 3) RPEpeak ≥ 19 in the 6–20 Borg scale [7].
Peak treadmill speed (Vpeak)
The Vpeak was determined according to previous studies [10] as either (a) the highest speed that could be maintained for a complete minute (Vpeak-60 s), (b) the speed of the last complete stage (Vpeak-C), i. e., the highest speed that could be maintained for more than 90 % of the stage duration, or (c) the speed of the last complete stage added to the product of the speed increment and the completed fraction of the incomplete stage [8] (Vpeak-P), calculated according to the equation Vpeak-P = Vcomplete + (Inc × t/T), in which Vcomplete is the running speed of the last complete stage, Inc the speed increment (i. e., 0.5 km · h − 1 for low-, 1 km · h − 1 for intermediate- and 2 km · h − 1 for high-increment protocol), t the number of seconds sustained during the incomplete stage, and T the number of seconds required to complete a stage (i. e., 180 s).
One-hour time trial running performance
Prior to the test, participants, who were accustomed to treadmill running tests, were instructed on the procedures of the test. The 1-h time trial running performance was preceded by a warm-up of walking at 6 km · h − 1 for 5 min, with the treadmill gradient set at 1 %. Thereafter, participants were encouraged to run their best performance, running as far as possible in 60 min [17, 19]. During the tests, participants controlled the treadmill speed, decreasing or increasing it, but only had access to the elapsed time. Still mineral water was provided for the participants to hydrate as they typically do in long distance endurance races
Peserico CS et al. Evaluation of the Best-designed … Int J Sports Med 2015; 36: 729–734
Downloaded by: Rutgers University. Copyrighted material.
However, these findings were valid for a fixed speed increment of 1 km · h − 1, and as the different speed increments might affect these relationships, this is a scientific gap concerning the Vpeak as performance predictor that need to be clarified. Therefore, the purpose of this study was to examine the influence of different speed increments (i. e., 0.5, 1.0 or 2.0 km · h − 1) during treadmill exercise tests on Vpeak and its relationship with a 1-h treadmill running performance in recreational runners. We hypothesized that this relationship would be influenced by different speed increments and Vpeak values derived from different criteria. Based on the results we intend to suggest a bestdesigned graded exercise test to assess Vpeak to predict endurance running performance.
Training & Testing
Statistical analyses
Data are presented as mean ± SD and were analyzed using the Statistical Package for the Social Sciences 17.0 software (SPSS Inc., USA). The Shapiro-Wilk test was used to check the normality of the data distribution. The relationship between Vpeak and S1-h was examined using Pearson product-moment correlation coefficient (r), adjusted coefficient of determination (R2), and standard error of estimate (SEE) for the 68 % confidence interval. When interpreting the correlation tests results, in addition to significance (P 0.75) estimates of sphericity. Statistical significance was set at P
729
Evaluation of the Best-designed Graded Exercise Test to Assess Peak Treadmill Speed
Authors
C. S. Peserico1, A. M. Zagatto2, F. A. Machado1
Affiliations
1
Key words ▶ physical endurance ● ▶ running ● ▶ exercise test ● ▶ athletic performance ● ▶ sports physiology ●
Abstract
Department of Physical Education, State University of Maringá, Maringá, Brazil Department of Physical Education, Sao Paulo State University, Bauru, Brazil
▼
This study examined the influence of different speed increments during treadmill exercise tests on peak treadmill speed (Vpeak) and its relationship with a 1-h treadmill running performance. 18 male recreational and amateur runners (10km running pace: 10–15 km · h − 1) performed, in an alternate order, 3 continuous incremental exercise tests with different speed increments (0.5, 1.0 and 2.0 km · h − 1) on a motorized treadmill to determine Vpeak. Thereafter they undertook a 1-h time trial on a treadmill. Vpeak was determined as either (a) the highest speed that could be maintained for a complete minute (Vpeak-60 s), (b) the speed of the last complete
Introduction
▼
accepted after revision January 21, 2015 Bibliography DOI http://dx.doi.org/ 10.1055/s-0035-1547225 Published online: April 14, 2015 Int J Sports Med 2015; 36: 729–734 © Georg Thieme Verlag KG Stuttgart · New York ISSN 0172-4622 Correspondence Fabiana Andrade Machado Department of Physical Education State University of Maringá Av. Colombo, 5790 87.020-900, Maringá Brazil Tel.: + 55/44/3011 4315 Fax: + 55/44/3011 4470 [email protected]
The peak treadmill speed obtained during an incremental exercise test (Vpeak) is a good predictor of endurance performance in runners [10, 14, 22] and can be determined without the use of expensive metabolic equipment or invasive techniques [20]. However, the design of an incremental test can affect the responses of Vpeak and its relationship with endurance running performance [2, 10]. Machado et al. [10] recently showed that incremental treadmill tests comprising 3-min stage duration were preferred to 1-min and 2-min stage duration protocols in order to determine Vpeak to accurately predict 5-km and 10-km running performances. However, this is a unique study, and the influences of speed increments during treadmill exercise tests on Vpeak and its relationship with endurance running performance remain unknown. Sports scientists and coaches generally use a wide range of speed increment during incremental exercise tests. However, the test design may
stage (Vpeak-C), or (c) the speed of the last complete stage added to the product of the speed increment and the completed fraction of the incomplete stage (Vpeak-P). The Vpeak values were highly influenced by the different speed-incremented rates and the Vpeak-P determined during the protocol comprising speed increments of 1 km · h − 1 presented the highest correlation with 1-h time trial performance (r = 0.89). The results suggest that a protocol with speed increments comprising 1 km · h − 1 and with a 3-min stage duration should be used as standard for the determination of Vpeak to assess aerobic fitness and predict endurance performance in recreational runners. Furthermore, the Vpeak-P should be used for the determination of Vpeak.
influence the Vpeak and consequently may change the validity of using it for predicting performance and monitoring training [2]. Thus it is important to elucidate the effects of speed increments during treadmill exercise tests on Vpeak and its relationship with endurance running performance. The major shortcoming of the study from Machado et al. [10] was that the running performances were determined on a 400-m outdoor running track, unsheltered from environmental conditions. Alterations in these variables could have affected the associations between Vpeak and endurance running performance. Thus, selfpaced running performances under laboratory conditions involving the use of a motorized treadmill could avoid this shortcoming. Machado et al. [10] also compared 3 Vpeak values, determined from different criteria, and examined their relationship with performance. They concluded that, independent of the stage duration, the Vpeak as defined according to Kuipers et al. [8] criterion provided the highest correlation with running performances, and should be used as a standard for the determination of Vpeak.
Peserico CS et al. Evaluation of the Best-designed … Int J Sports Med 2015; 36: 729–734
Downloaded by: Rutgers University. Copyrighted material.
2
730 Training & Testing
Methods
▼
Participants
18 male recreational and amateur runners with experience in 10-km running races and involved in systematic training volunteered to participate in this study. Characteristics of the participants (mean ± SD) were: age 25.5 ± 3.3 years, height 178.0 ± 7.0 cm, body mass 76.2 ± 8.6 kg, body mass index (BMI) 24.1 ± 2.3 kg · m − 2 and body fat 13.9 ± 3.0 %. The training characteristics were experience 3.8 ± 3.3 years, frequency 3.2 ± 1.1 days · wk − 1 and distance 27.4 ± 17.0 km · wk − 1. The 10-km running times of the participants were between 40 and 60 min, with a pace between 10 and 15 km · h − 1 (≅ 44–66 % of the world record). Prior to testing, written informed consent was obtained from all participants. The experimental protocol was approved by the local ethics committee (#719/2010). All research was conducted ethically according to international standards and as required by the International Journal of Sports Medicine [6].
Experimental design
Participants who were accustomed to treadmill running tests performed 3 continuous incremental exercise tests with different speed increments on a motorized treadmill (Super ATL; Inbrasport, Porto Alegre, Brazil), with the gradient set at 1 %, to determine Vpeak that is a reliable and accurate measure [15]. First, participants performed each of the 3 protocols in an alternate order. Thereafter, each participant performed the 3 tests again, maintaining the same order as before. The 3 incremental protocols were as follows: (a) low-increment protocol with increments of 0.5 km · h − 1, (b) intermediate-increment protocol with increments of 1 km · h − 1, and (c) high-increment protocol with increments of 2 km · h − 1. The 6 incremental tests were performed over 3 weeks, with each test separated from the other by at least 72 h. The better of 2 performances for each participant during each protocol was recorded and used in the results. Thereafter, within a 7-day period after the incremental tests, the participants undertook a 1-h time trial under laboratory conditions, in which the participants ran as far as possible on a motorized treadmill by setting their own pace throughout the test [19]. 1-h time trial treadmill performance is a reliable test with a coefficient of variation (CV) generally below 3 % [17, 19]. Participants were instructed to report for testing well-rested, wellnourished, and well-hydrated, wearing lightweight comfortable clothing. Participants were also instructed to avoid eating 2 h before the tests, to abstain from caffeine and alcohol, and to refrain from the training routines during testing.
Incremental exercise protocols
After a warm-up that consisted of walking at 6 km · h − 1 for 3 min, each protocol started with an initial treadmill speed of 8 km · h − 1, followed by an increase of 0.5 km · h − 1, 1 km · h − 1 or 2 km · h − 1 between each successive stage of 3 min until participants reached their volitional exhaustion. Consistently across each trial, participants were strongly encouraged, verbally, to invest maximum effort. The tests were performed in the morning, at the same time of the day, under normal laboratory conditions (temperature = 20–22 °C and relative humidity = 50–60 %).
Psychophysiological and physiological variables
Before testing, participants were familiarized with the 6-20 Borg scale [3] which was used to measure the rating of perceived exertion (RPE) during the last 15 s of each stage and at exhaustion. The highest RPE value was adopted as the peak RPE (RPEpeak). The HR was recorded every 5 s throughout the tests (Polar RS800SD, Kempele, Finland) and the maximal heart rate (HRmax) was defined as the highest HR value recorded during the tests [23]. Neither respiratory gases nor blood lactate was monitored during the tests given that such interventions could impair the performance of the participants [19]. Earlobe capillary blood samples (25 µL) were collected into a capillary tube after the end of each test, at the fifth minute of passive recovery, sitting in a comfortable chair. From these samples, blood lactate concentration was subsequently determined by electroenzymatic methods using an automated analyzer (YSI 2300 STAT, Ohio, USA) for the determination of peak blood lactate concentration (LApeak) post-exercise. The maximal effort was deemed to be achieved if the incremental test met 2 of the following criteria: 1) LApeak ≥ 8 mmol · L − 1, 2) HRmax ≥ 95 % of endurance-trained age-predicted maximum heart rate (APMHR) using the age-based (206– 0.7 × age) equation [23] and 3) RPEpeak ≥ 19 in the 6–20 Borg scale [7].
Peak treadmill speed (Vpeak)
The Vpeak was determined according to previous studies [10] as either (a) the highest speed that could be maintained for a complete minute (Vpeak-60 s), (b) the speed of the last complete stage (Vpeak-C), i. e., the highest speed that could be maintained for more than 90 % of the stage duration, or (c) the speed of the last complete stage added to the product of the speed increment and the completed fraction of the incomplete stage [8] (Vpeak-P), calculated according to the equation Vpeak-P = Vcomplete + (Inc × t/T), in which Vcomplete is the running speed of the last complete stage, Inc the speed increment (i. e., 0.5 km · h − 1 for low-, 1 km · h − 1 for intermediate- and 2 km · h − 1 for high-increment protocol), t the number of seconds sustained during the incomplete stage, and T the number of seconds required to complete a stage (i. e., 180 s).
One-hour time trial running performance
Prior to the test, participants, who were accustomed to treadmill running tests, were instructed on the procedures of the test. The 1-h time trial running performance was preceded by a warm-up of walking at 6 km · h − 1 for 5 min, with the treadmill gradient set at 1 %. Thereafter, participants were encouraged to run their best performance, running as far as possible in 60 min [17, 19]. During the tests, participants controlled the treadmill speed, decreasing or increasing it, but only had access to the elapsed time. Still mineral water was provided for the participants to hydrate as they typically do in long distance endurance races
Peserico CS et al. Evaluation of the Best-designed … Int J Sports Med 2015; 36: 729–734
Downloaded by: Rutgers University. Copyrighted material.
However, these findings were valid for a fixed speed increment of 1 km · h − 1, and as the different speed increments might affect these relationships, this is a scientific gap concerning the Vpeak as performance predictor that need to be clarified. Therefore, the purpose of this study was to examine the influence of different speed increments (i. e., 0.5, 1.0 or 2.0 km · h − 1) during treadmill exercise tests on Vpeak and its relationship with a 1-h treadmill running performance in recreational runners. We hypothesized that this relationship would be influenced by different speed increments and Vpeak values derived from different criteria. Based on the results we intend to suggest a bestdesigned graded exercise test to assess Vpeak to predict endurance running performance.
Training & Testing
Statistical analyses
Data are presented as mean ± SD and were analyzed using the Statistical Package for the Social Sciences 17.0 software (SPSS Inc., USA). The Shapiro-Wilk test was used to check the normality of the data distribution. The relationship between Vpeak and S1-h was examined using Pearson product-moment correlation coefficient (r), adjusted coefficient of determination (R2), and standard error of estimate (SEE) for the 68 % confidence interval. When interpreting the correlation tests results, in addition to significance (P 0.75) estimates of sphericity. Statistical significance was set at P
