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Sample records for vo2max exhaustive cycling

  1. A comparison of time to exhaustion at VO2 max in élite cyclists, kayak paddlers, swimmers and runners.

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    Billat, V; Faina, M; Sardella, F; Marini, C; Fanton, F; Lupo, S; Faccini, P; de Angelis, M; Koralsztein, J P; Dalmonte, A

    1996-02-01

    A recent study has shown the reproducibility of time to exhaustion (time limit: tlim) at the lowest velocity that elicits the maximal oxygen consumption (vVO2 max). The same study found an inverse relationship between this time to exhaustion at vVO2 max and vVO2 max among 38 élite long-distance runners (Billat et al. 1994b). The purpose of the present study was to compare the time to exhaustion at the power output (or velocity) at VO2 max for different values of VO2 max, depending on the type of exercise and not only on the aerobic capacity. The time of exhaustion at vVO2 max (tlim) has been measured among 41 élite (national level) sportsmen: 9 cyclists, 9 kayak paddlers, 9 swimmers and 14 runners using specific ergometers. Velocity or power at VO2 max (vVO2 max) was determined by continuous incremental testing. This protocol had steps of 2 min and increments of 50 W, 30 W, 0.05 m s-1 and 2 km-1 for cyclists, kayak paddlers, swimmers and runners, respectively. One week later, tlim was determined under the same conditions. After a warm-up of 10 min at 60% of their vVO2 max, subjects were concluded (in less than 45 s) to their vVO2 max and then had to sustain it as long as possible until exhaustion. Mean values of vVO2 max and tlim were respectively equal to 419 +/- 49 W (tlim = 222 +/- 91 s), 239 +/- 56 W (tlim = 376 +/- 134 s), 1.46 +/- 0.09 m s-1 (tlim = 287 +/- 160 s) and 22.4 +/- 0.8 km h-1 (tlim = 321 +/- 84 s), for cyclists, kayak paddlers, swimmers and runners. Time to exhaustion at vVO2 max was only significantly different between cycling and kayaking (ANOVA test, p < 0.05). Otherwise, VO2 max (expressed in ml min-1 kg-1) was significantly different between all sports except between cycling and running (p < 0.05). In this study, time to exhaustion at vVO2 max was also inversely related to VO2 max for the entire group of élite sportsmen (r = -0.320, p < 0.05, n = 41). The inverse relationship between VO2 max and tlim at vVO2 max has to be explained, it

  2. Time to Exhaustion at the VO2max Velocity in Swimming: A Review.

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    Fernandes, Ricardo J; Vilas-Boas, J Paulo

    2012-05-01

    The aim of this study was to present a review on the time to exhaustion at the minimum swimming velocity corresponding to maximal oxygen consumption (TLim-vVO2max). This parameter is critical both for the aerobic power and the lactate tolerance bioenergetical training intensity zones, being fundamental to characterize it, and to point out its main determinants. The few number of studies conducted in this topic observed that swimmers were able to maintain an exercise intensity corresponding to maximal aerobic power during 215 to 260 s (elite swimmers), 230 to 260 s (high level swimmers) and 310 to 325 s (low level swimmers), and no differences between genders were reported. TLim-vVO2max main bioenergetic and functional determinants were swimming economy and VO2 slow component (direct relationship), and vVO2max, velocity at anaerobic threshold and blood lactate production (inverse relationship); when more homogeneous groups of swimmers were analysed, the inverse correlation value between TLim-vVO2max and vVO2max was not so evident. In general, TLim-vVO2max was not related to VO2max. TLim-vVO2max seems also to be influenced by stroking parameters, with a direct relationship to stroke length and stroke index, and an inverse correlation with stroke rate. Assessing TLim-vVO2max, together with the anaerobic threshold and the biomechanical general parameters, will allow a larger spectrum of testing protocols application, helping to build more objective and efficient training programs.

  3. Time to Exhaustion at the VO2max Velocity in Swimming: A Review

    OpenAIRE

    Fernandes, Ricardo J.; Vilas-Boas, J. Paulo

    2012-01-01

    The aim of this study was to present a review on the time to exhaustion at the minimum swimming velocity corresponding to maximal oxygen consumption (TLim-vVO2max). This parameter is critical both for the aerobic power and the lactate tolerance bioenergetical training intensity zones, being fundamental to characterize it, and to point out its main determinants. The few number of studies conducted in this topic observed that swimmers were able to maintain an exercise intensity corresponding to...

  4. Effect of protocol on determination of velocity at VO2 max and on its time to exhaustion.

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    Billat, V L; Hill, D W; Pinoteau, J; Petit, B; Koralsztein, J P

    1996-01-01

    The velocity associated with the achievement of VO2 max during an incremental treadmill test (v VO2 max) has been reported to be an indicator of performance in middle distance running events. Previous study has shown the reproducibility of the time to exhaustion (time limit: tlim) at v VO2 max performed by well-trained males in the same condition at one week of interval (Billat et al., 1994b). It is essential in studies involving tlim at v VO2 max that the v VO2 max be precisely determined, or else the measured tlim will be meaningless. The purpose of this study was to examine the influence of the stage duration and velocity incrementation on the velocity at VO2 max and, consequently, on the two times to exhaustion (tlim) associated with the two v VO2 max generated by the two protocols. v VO2 max was determined in 15 trained male endurance athletes as the lowest speed at which VO2 max was attained in speed-incremented 0%-slope treadmill tests. For one test, increments were 1.0 km.h-1 and stages were 2 min in duration; for the other test, increments were 0.5 km.h-1 and stages were 1 min in duration. Results of paired means t-tests revealed no difference in v VO2 max obtained using the two protocols. v VO2 max was 20.7 +/- 1.0 km.h-1 with the 1.0 km.h-1 x 2 min protocol and 20.8 +/- 0.9 km.h-1 with the 0.5 km.h-1 x 1 min protocol. In addition, VO2, VCO2, VE, VE/VO2 and respiratory exchange ratio at the submaximal intensities that were common to both protocols (e.g., 17.0 km.h-1, 18.0 km.h-1, 19.0 km.h-1, 20.0 km.h-1) did not differ. Times to exhaustion at the two v VO2 max demonstrated a high degree of inter-individual variability (coefficients of variation were 35% and 45%) but did not differ (345 +/- 120 s versus 373 +/- 169 s). These results demonstrated that small changes in protocol have no significant impact on the value of v VO2 max and in consequence on tlim v VO2 max.

  5. Prediction VO2max during cycle ergometry based on submaximal ventilatory indicators.

    Science.gov (United States)

    Nunes, Rodolfo Alkmim Moreira; Vale, Rodrigo Gomes de Souza; Simão, Roberto; de Salles, Belmiro Freitas; Reis, Victor Machado; Novaes, Jefferson da Silva; Miranda, Humberto; Rhea, Matthew R; Medeiros, Aldo da Cunha

    2009-09-01

    There are several equations to predict maximum oxygen consumption (VO2max) from ergometric test variables on different ergometers. However, a similar equation using ventilatory thresholds of ergospirometry in a submaximal test on a cycle ergometer is unavailable. The aim of the present study was to assess the accuracy of VO2max prediction models based on indicators of submaximal effort. Accordingly, 4,640 healthy, nonathlete women ages 20 years and older volunteered to be tested on a cycle ergometer using a maximum incremental protocol. The subjects were randomly assigned to 2 groups: group A (estimation) and group B (validation). From the independent variables of weight in kilograms, the second workload threshold (WT2), and heart rate of the second threshold (HRT2), it was possible to build a multiple linear regression model to predict maximal oxygen consumption (VO2max = 40.302 - 0.497 [Weight] - 0.001 [HRT2] + 0.239 [WT2] in mL O2/kg/min(-1); r = 0.995 and standard error of the estimate [SEE] = 0.68 mL O2/kg/min(-1)). The cross-validation method was used in group B with group A serving as the basis for building the model and the validation dataset. The results showed that, in healthy nonathlete women, it is possible to predict VO2max with a minimum of error (SEE = 1.00%) from submaximal indicators obtained in an incremental test.

  6. Specificity of VO2MAX and the ventilatory threshold in free swimming and cycle ergometry: comparison between triathletes and swimmers.

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    Roels, B; Schmitt, L; Libicz, S; Bentley, D; Richalet, J-P; Millet, G

    2005-12-01

    To compare maximal heart rate (HRmax), maximal oxygen consumption (VO2MAX), and the ventilatory threshold (VT; %VO2MAX) during cycle ergometry and free swimming between swimmers and triathletes. Nine swimmers and ten triathletes completed an incremental swimming and cycling test to exhaustion. Whole body metabolic responses were determined in each test. The swimmers exhibited a significantly higher VO2MAX in swimming than in cycling (58.4 (5.6) v 51.3 (5.1) ml/kg/min), whereas the opposite was found in the triathletes (53.0 (6.7) v 68.2 (6.8) ml/kg/min). HRmax was significantly different in the maximal cycling and swimming tests for the triathletes (188.6 (7.5) v 174.8 (9.0) beats/min). In the maximal swimming test, HRmax was significantly higher in the swimmers than in the triathletes (174.8 (9.0) v 184.6 (9.7) beats/min). No significant differences were found for VT measured in swimming and cycling in the triathletes and swimmers. This study confirms that the exercise testing mode affects the VO2MAX value, and that swimmers have very specific training adaptations even compared with triathletes. This may be a function of acute physiological responses combined with the specialist training status of the different athletes influencing maximal cardiac output or oxygen extraction. In contrast, the different training regimens do not seem to influence the VT, as this variable did not differ between the two testing modes in either group.

  7. A new submaximal cycle ergometer test for prediction of VO2max.

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    Ekblom-Bak, E; Björkman, F; Hellenius, M-L; Ekblom, B

    2014-04-01

    Maximal oxygen uptake (VO2max) is an important, independent predictor of cardiovascular health and mortality. Despite this, it is rarely measured in clinical practice. The aim of this study was to create and evaluate a submaximal cycle ergometry test based on change in heart rate (HR) between a lower standard work rate and an individually chosen higher work rate. In a mixed population (n = 143) with regard to sex (55% women), age (21-65 years), and activity status (inactive to highly active), a model included change in HR per unit change in power, sex, and age for the best estimate of VO2max. The association between estimated and observed VO2max for the mixed sample was r = 0.91, standard error of estimate = 0.302 L/min, and mean measured VO2max = 3.23 L/min. The corresponding coefficient of variation was 9.3%, a significantly improved precision compared with one of the most commonly used submaximal exercise tests, the Åstrand test, which in the present study was estimated to be 18.1%. Test-retest reliability analysis over 1 week revealed no mean difference in the estimated VO2max (-0.02 L/min, 95% confidence interval: -0.07-0.03). The new test is low-risk, easily administered, and valid for a wide capacity range, and is therefore suitable in situations as health evaluations in the general population. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Efeitos do estado e especificidade do treinamento aeróbio na relação %VO2max versus %FCmax durante o ciclismo Effects of the state and specificity of aerobic training on the %VO2max versus %HRmax ratio during cycling

    Directory of Open Access Journals (Sweden)

    Fabrizio Caputo

    2005-01-01

    Full Text Available OBJETIVO: Determinar os efeitos do estado e especificidade de treinamento aeróbio na relação entre o percentual do consumo máximo de oxigênio (%VO2max e o percentual da frequência cardíaca máxima (%FCmax durante o exercício incremental realizado no cicloergômetro. MÉTODOS: Sete corredores, 9 ciclistas, 11 triatletas e 12 sedentários, todos do sexo masculino e aparentemente saudáveis, foram submetidos a um teste incremental até a exaustão no cicloergômetro. Regressões lineares entre %VO2max e %FCmax foram determinadas para cada indivíduo. Com base nessas regressões, foram calculados %FCmax correspondentes a determinados %VO2max (50, 60, 70, 80 e 90% de cada participante. RESULTADOS: Não foram encontradas diferenças significantes entre todos os grupos nos %FCmax para cada um dos %VO2max avaliados. Analisando-se os voluntários como um único grupo, as médias dos %FCmax correspondentes a 50, 60, 70, 80 e 90% %VO2max foram 67, 73, 80, 87, e 93%, respectivamente. CONCLUSÃO: Nos grupos analisados, a relação entre o %VO2max e %FCmax durante o exercício incremental no ciclismo não é dependente do estado e especificidade do treinamento aeróbio.OBJECTIVE: To determine the effects of the status and specificity of exercise training in the ratio between maximum oxygen consumption (%VO2max and the percentage of maximal heart rate (%HRmax during incremental exercise on a cycle ergometer. METHODS: Seven runners, 9 cyclists, 11 triathletes, and 12 sedentary individuals, all male and apparently healthy, underwent exhaustive incremental exercise on cycle ergometers. Linear regressions between %VO2max x %HRmax were determined for each individual. Based on these regressions, %HRmax was assessed corresponding to a determined %VO2max (50, 60, 70, 80, and 90% from each participant. RESULTS: Significant differences were not found between the groups in %HRmax for each of the %VO2max assessed. Analyzing the volunteers as a single group, the

  9. Strength training improves cycling performance, fractional utilization of VO2max and cycling economy in female cyclists.

    Science.gov (United States)

    Vikmoen, O; Ellefsen, S; Trøen, Ø; Hollan, I; Hanestadhaugen, M; Raastad, T; Rønnestad, B R

    2016-04-01

    The purpose of this study was to investigate the effect of adding heavy strength training to well-trained female cyclists' normal endurance training on cycling performance. Nineteen female cyclists were randomly assigned to 11 weeks of either normal endurance training combined with heavy strength training (E+S, n = 11) or to normal endurance training only (E, n = 8). E+S increased one repetition maximum in one-legged leg press and quadriceps muscle cross-sectional area (CSA) more than E (P < 0.05), and improved mean power output in a 40-min all-out trial, fractional utilization of VO2 max and cycling economy (P < 0.05). The proportion of type IIAX-IIX muscle fibers in m. vastus lateralis was reduced in E+S with a concomitant increase in type IIA fibers (P < 0.05). No changes occurred in E. The individual changes in performance during the 40-min all-out trial was correlated with both change in IIAX-IIX fiber proportion (r = -0.63) and change in muscle CSA (r = 0.73). In conclusion, adding heavy strength training improved cycling performance, increased fractional utilization of VO2 max , and improved cycling economy. The main mechanisms behind these improvements seemed to be increased quadriceps muscle CSA and fiber type shifts from type IIAX-IIX toward type IIA.

  10. .VO2max is not altered by self-pacing during incremental exercise.

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    Chidnok, Weerapong; Dimenna, Fred J; Bailey, Stephen J; Burnley, Mark; Wilkerson, Daryl P; Vanhatalo, Anni; Jones, Andrew M

    2013-02-01

    We tested the hypothesis that incremental cycling to exhaustion that is paced using clamps of the rating of perceived exertion (RPE) elicits higher .VO2max values compared to a conventional ramp incremental protocol when test duration is matched. Seven males completed three incremental tests to exhaustion to measure .VO2max. The incremental protocols were of similar duration and included: a ramp test at 30 W min(-1) with constant cadence (RAMP1); a ramp test at 30 W min(-1) with cadence free to fluctuate according to subject preference (RAMP2); and a self-paced incremental test in which the power output was selected by the subject according to prescribed increments in RPE (SPT). The subjects also completed a .VO2max 'verification' test at a fixed high-intensity power output and a 3-min all-out test. No difference was found for .VO2max between the incremental protocols (RAMP1 = 4.33 ± 0.60 L min(-1); RAMP2 = 4.31 ± 0.62 L min(-1); SPT = 4.36 ± 0.59 L min(-1); P > 0.05) nor between the incremental protocols and the peak.VO2max measured during the 3-min all-out test (4.33 ± 0.68 L min(-1)) or the .VO2max measured in the verification test (4.32 ± 0.69 L min(-1)). The integrated electromyogram, blood lactate concentration, heart rate and minute ventilation at exhaustion were not different (P > 0.05) between the incremental protocols. In conclusion, when test duration is matched, SPT does not elicit a higher .VO2max compared to conventional incremental protocols. The striking similarity of .VO2max measured across an array of exercise protocols indicates that there are physiological limits to the attainment of .VO2max that cannot be exceeded by self-pacing.

  11. [Effect of 4 weeks of training on the limit time at VO2 max].

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    Heubert, Richard; Bocquet, Valéry; Koralsztein, Jean Pierre; Billat, Véronique

    2003-10-01

    The purpose of this study was to examine the effect of 4 weeks training in running on the time spent at VO2max (tlim VO2max). Eight athletes carried out, before and after an aerobic training, an incremental and five exhaustive tests at 90, 95, 100, 115% vVO2max and at the critical power at VO2max (CV'; slope of the linear relation between the tlim VO2max and the distance limit at VO2max). This training did not significantly improve VO2max (p = 0.17) or tlim VO2max (p = 0.72). However, the "tlim VO2max-intensity" curve was shifted toward the right, meaning that the athlete had to run at a higher intensity after training to obtain the same tlim VO2max. Tlim VO2max at CV' before training was significantly higher than tlim VO2max at 90, 95, 100, and 115% vVO2max (p max; p = 0.9). In conclusion, in spite of the shift of the "tlim VO2max-intensity" curve, tlim VO2max was not significantly increased by this training. Furthermore, CV' allowed subjects to spend the longest time of exercise at VO2max during a continuous exercise with constant speed, but CV', expressed in % vVO2max, did not improve with this training.

  12. Leg strength and the VO2 max of older men.

    Science.gov (United States)

    Lovell, D; Cuneo, R; Delphinus, E; Gass, G

    2011-04-01

    The purpose of the study was to determine if leg strength limits VO2 max and the ability to reach a plateau during VO2 max test in older men during cycle ergometry. Men aged 70-80 years were randomly selected into a strength training (ST, n=12) 3 times weekly for 16 weeks, followed by 4 weeks detraining or a non-training control group (C, n=12). Leg strength and VO2 max were assessed every 4 weeks for 20 weeks; body composition and cardiac function were assessed before and after 16 weeks training and after 4 weeks detraining. Leg strength, upper leg muscle mass (ULMM), arterial-venous O2 difference (a-v O2 difference) and VO2 max increased in the ST group (95±0.6%, 7±0.7%. 6.2±0.5% and 8±0.8%, respectively; PVO2 max and a-v O2 difference returned to pre-training levels. There was no change in the ability of the participants to reach a plateau during VO2 max testing over the 20-week study. These findings indicate that leg strength may not limit either VO2 max or the ability to plateau during VO2 max tests in older men during cycle ergometry. © Georg Thieme Verlag KG Stuttgart · New York.

  13. Estimation of VO2 Max: A Comparative Analysis of Five Exercise Tests.

    Science.gov (United States)

    Zwiren, Linda D.; And Others

    1991-01-01

    Thirty-eight healthy females measured maximal oxygen uptake (VO2max) on the cycle ergometer and treadmill to compare five exercise tests (run, walk, step, and two tests using heart-rate response on the bicycle ergometer) in predicting VO2max. Results indicate that walk and run tests are satisfactory predictors of VO2max in 30- to 39-year-old…

  14. Assessment of anaerobic power to verify VO2max attainment.

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    Astorino, Todd A; White, Ailish C

    2010-07-01

    Across various populations, verification testing is used to confirm VO(2)max attainment and has repeatedly shown similar VO(2)max values to those obtained from incremental exercise. Yet, many individuals show meaningful differences in VO(2)max between protocols, and an explanation for this is unknown. The aim of the study was to elucidate this phenomenon in 30 men and women of similar age, fitness, and physical activity using assessment of anaerobic power. On day 1, they completed the Wingate test, and returned at least 48 h later to complete incremental cycle ergometry followed by a verification protocol. During exercise, ventilation, pulmonary gas exchange data, and heart rate (HR) were continuously measured. Mean VO(2)max was similar (P > 0.05) between protocols (42.05 +/- 5.88 ml kg(-1) per min versus 42.03 +/- 5.75 ml kg(-1) per min, respectively), although seven subjects (23%) revealed a VO(2)max that was not 'verified' by the supramaximal protocol. Indices of power output and gas exchange data were similar (P > 0.05) between subjects who revealed a 'true' VO(2)max compared to those who did not, although peak and mean power was consistently higher in persons whose VO(2)max was not 'verified.' A previously established HRmax criterion for verification testing was not met in 17% of subjects. Additional study is merited to identify alternate determinants of VO(2)max, such as muscle activation via assessment of motor unit recruitment, and to investigate utility of verification testing to confirm VO(2)max attainment in elite athletes and the elderly.

  15. Frequency of the VO2max plateau phenomenon in world-class cyclists.

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    Lucía, A; Rabadán, M; Hoyos, J; Hernández-Capilla, M; Pérez, M; San Juan, A F; Earnest, C P; Chicharro, J L

    2006-12-01

    We aimed to determine the frequency of the VO2max plateau phenomenon in top-level male professional road cyclists (n = 38; VO2max [mean +/- SD]: 73.5 +/- 5.5 ml.kg(-1).min(-1)) and in healthy, sedentary male controls (n = 37; VO2max: 42.7 +/- 5.6 ml.kg(-1).min(-1)). All subjects performed a continuous incremental cycle-ergometer test of 1-min workloads until exhaustion. Power output was increased from a starting value of 25 W (cyclists) or 20 W (controls) at the rate of 25 W.min(-1) (cyclists) or 20 W.min(-1) (controls) until volitional exhaustion. We measured gas-exchange and heart rate (HR) throughout the test. Blood concentrations of lactate (BLa) were measured at end-exercise in both groups. We defined maximal exercise exertion as the attainment of a respiratory exchange rate (RER) >or= 1.1; HR > 95 % age-predicted maximum; and BLa > 8 mmo.l(-1). The VO2max plateau phenomenon was defined as an increase in two or more consecutive 1-min mean VO2 values of less than 1.5 ml.kg(-1).min(-1). Most cyclists met our criteria for maximal exercise effort (RER > 1.1, 100 %; 95 % predicted maximal HR [HRmax], 82 %; BLa > 8 mmol.l(-1), 84 %). However, the proportion of cyclists attaining a V.O (2max) plateau was considerably lower, i.e., 47 %. The majority of controls met the criteria for maximal exercise effort (RER > 1.1, 100 %; predicted HRmax, 68 %; BLa > 8 mmol. l(-1), 73 %), but the proportion of these subjects with a VO2max plateau was only 24 % (significantly lower proportion than in cyclists [p < 0.05]). Scientists should consider 1) if typical criteria of attainment of maximal effort are sufficiently stringent, especially in elite endurance athletes; and 2) whether those humans exhibiting the VO2max plateau phenomenon are those who perform an absolute maximum effort or there are additional distinctive features associated with this phenomenon.

  16. Validity of 3 protocols for verifying VO2 max.

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    Kirkeberg, J M; Dalleck, L C; Kamphoff, C S; Pettitt, R W

    2011-04-01

    The verification bout has emerged as a technique for confirming 'true' VO2 max; however, validity during a single visit is unknown. We evaluated 3 different GXT durations with severe intensity verification bouts. On 3 separate days, in counterbalanced order, 12 recreational-trained men completed short (9±1 min), middle (11±1 min), and long (13±2 min) duration GXTs followed by exhaustive, sine wave verification bouts during the same visit. Intensities for verification were set at speeds equivalent to 2-stages minus end-GXT speed. No differences (pVO2 max (mL/kg/min) were observed between short (49.1), middle (48.2), and long (48.8) protocols. In addition, no differences in verification bout duration occurred between protocols (3±1 min). Validity of VO2 max was strongest for the middle duration protocol (ICC α=0.97; typical error=1 mL/kg/min; CV=2%). A small, but significantly higher HR (max) (∼1-2 bpm) was observed for the long protocol. Maximum respiratory exchange ratios were inconsistent (ICC α ranged 0.58-0.68). Our findings indicate GXT-verification bout testing during a single visit is a valid means of measuring 'true' VO2 max. The 10 min target for GXT duration was the optimum. © Georg Thieme Verlag KG Stuttgart · New York.

  17. [VO2 max, a true exercise test].

    Science.gov (United States)

    Saunier, Carole

    2013-01-01

    VO2 max is nowadays an essential examination performed in the monitoring of heart failure. The nurse has a role to play during the test and in supporting the patient, although this test remains highly technical and complex.

  18. The Effect of Aging on Relationships between Lean Body Mass and VO2max in Rowers.

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    Kim, Chul-Ho; Wheatley, Courtney M; Behnia, Mehrdad; Johnson, Bruce D

    2016-01-01

    Aging is associated with a fall in maximal aerobic capacity as well as with a decline in lean body mass. The purpose of the study was to investigate the influence of aging on the relationship between aerobic capacity and lean body mass in subjects that chronically train both their upper and lower bodies. Eleven older rowers (58±5 yrs) and 11 younger rowers (27±4 yrs) participated in the study. Prior to the VO2max testing, subjects underwent a dual energy X-ray absorptiometry scan to estimate total lean body mass. Subsequently, VO2max was quantified during a maximal exercise test on a rowing ergometer as well as a semi-recumbent cycle ergometer. The test protocol included a pre-exercise stage followed by incremental exercise until VO2max was reached. The order of exercise modes was randomized and there was a wash-out period between the two tests. Oxygen uptake was obtained via a breath-by-breath metabolic cart (Vmax™ Encore, San Diego, CA). Rowing VO2max was higher than cycling VO2max in both groups (pVO2max from cycling to rowing (pVO2max for both groups (pVO2max between groups disappeared (p>0.05), however, older subjects still demonstrated a lower rowing VO2max relative to younger subjects (pVO2max obtained, however, it appears that VO2max in older subjects may be less influenced by muscle mass than in younger subjects.

  19. Time limit and time at VO2max' during a continuous and an intermittent run.

    Science.gov (United States)

    Demarie, S; Koralsztein, J P; Billat, V

    2000-06-01

    The purpose of this study was to verify, by track field tests, whether sub-elite runners (n=15) could (i) reach their VO2max while running at v50%delta, i.e. midway between the speed associated with lactate threshold (vLAT) and that associated with maximal aerobic power (vVO2max), and (ii) if an intermittent exercise provokes a maximal and/or supra maximal oxygen consumption longer than a continuous one. Within three days, subjects underwent a multistage incremental test during which their vVO2max and vLAT were determined; they then performed two additional testing sessions, where continuous and intermittent running exercises at v50%delta were performed up to exhaustion. Subject's gas exchange and heart rate were continuously recorded by means of a telemetric apparatus. Blood samples were taken from fingertip and analysed for blood lactate concentration. In the continuous and the intermittent tests peak VO2 exceeded VO2max values, as determined during the incremental test. However in the intermittent exercise, peak VO2, time to exhaustion and time at VO2max reached significantly higher values, while blood lactate accumulation showed significantly lower values than in the continuous one. The v50%delta is sufficient to stimulate VO2max in both intermittent and continuous running. The intermittent exercise results better than the continuous one in increasing maximal aerobic power, allowing longer time at VO2max and obtaining higher peak VO2 with lower lactate accumulation.

  20. A new non-exercise-based Vo2max prediction equation for aerobically trained men.

    Science.gov (United States)

    Malek, Moh H; Housh, Terry J; Berger, Dale E; Coburn, Jared W; Beck, Travis W

    2005-08-01

    The purposes of the present study were to (a) modify previously published Vo(2)max equations using the constant error (CE = mean difference between actual and predicted Vo(2)max) values from Malek et al. (28); (b) cross-validate the modified equations to determine their accuracy for estimating Vo(2)max in aerobically trained men; (c) derive a new non- exercise-based equation for estimating Vo(2)max in aerobically trained men if the modified equations are not found to be accurate; and (d) cross-validate the new Vo(2)max equation using the predicted residual sum of squares (PRESS) statistic and an independent sample of aerobically trained men. One hundred and fifty-two aerobically trained men (Vo(2)max mean +/- SD = 4,154 +/- 629 ml.min(-1)) performed a maximal incremental test on a cycle ergometer to determine actual Vo(2)max. An aerobically trained man was defined as someone who had participated in continuous aerobic exercise 3 or more sessions per week for a minimum of 1 hour per session for at least the past 18 months. Nine previously published Vo(2)max equations were modified for use with aerobically trained men. The predicted Vo(2)max values from the 9 modified equations were compared to actual Vo(2)max by examining the CE, standard error of estimate (SEE), validity coefficient (r), and total error (TE). Cross-validation of the modified non-exercise-based equations on a random subsample of 50 subjects resulted in a %TE > or = 13% of the mean of actual Vo(2)max. Therefore, the following non-exercise-based Vo(2)max equation was derived from a random subsample of 112 subjects: Vo(2)max (ml.min(-1)) = 27.387(weight in kg) + 26.634(height in cm) - 27.572(age in years) + 26.161(h.wk(-1) of training) + 114.904(intensity of training using the Borg 6-20 scale) + 506.752(natural log of years of training) - 4,609.791 (R = 0.82, R(2) adjusted = 0.65, and SEE = 378 ml.min(-1)). Cross-validation of this equation on the remaining sample of 40 subjects resulted in a %TE of 10

  1. VO2 max in an Indian population: a study to understand the role of factors determining VO2 max.

    Science.gov (United States)

    Nitin, Y M; Sucharita, S; Madhura, M; Thomas, T; Sandhya, T A

    2013-01-01

    VO2 max is the maximum amount of oxygen a person can consume and the value does not change despite an increase in workload. There is lack of data evaluating the impact of factors, which could affect VO2 max measurement, particularly in Indian population. The objectives of the present study were (i) to estimate VO2 max in a young healthy Indian population and to compare it with available prediction equations for Indian population (ii) to correlate time to achieve VO2 max with the relative VO2 max (iii) to assess the factors affecting the time to achieve VO2 max measurement (body composition and physical activity level). Twenty healthy adult males (18-30 years) underwent detailed anthropometry, physical activity level and modified Bruce protocol for VO2 max assessment. Breath by breath VO2, VCO2, oxygen saturation, heart rate, blood pressure were measured continuously and following exercise protocol. There was an internal validity between the estimated VO2 max and the maximum heart rate (MHR) (r = 0.51, P VO2 max P VO2 max. Out of the 3 prediction equations computed to estimate VO2 max, 2 equations significantly overestimated VO2 max. In Conclusion, physical activity level emerged to be a strong predictor of time to VO2 max. Time to achieve VO2 max is an important factor to be considered when determining VO2 max. There was an overestimation in the VO2 max values derived from predicted equations.

  2. Is time limit at the minimum swimming velocity of VO2 max influenced by stroking parameters?

    Science.gov (United States)

    Fernandes, Ricardo J; Marinho, Daniel A; Barbosa, Tiago M; Vilas-Boas, J Paulo

    2006-08-01

    The aim of this study was to observe the relationship between time limit at the minimum velocity that elicits maximal oxygen consumption (TLim-v VO2 max) and stroke rate, stroke length, and stroke index. 13 men and 10 women, highly trained swimmers, performed an intermittent incremental test for v VO2 max assessment and an all-out swim to estimate TLim-v VO2 max. The mean +/- SD TLim-v VO2 max, v VO2 max, stroke rate, stroke length, and stroke index values were 233.36 +/- 53.92 sec., 1.40 +/- .06 meter/sec., 35.58 +/- 2.89 cycles/min., 2.39 +/- .22 meter/cycle, and 3.36 +/- .41 meter2/(cycle x sec.), respectively. The correlation between TLim-v VO2 max and stroke rate was -.51 (p VO2 max with stroke length (r = .52, p < .01) and stroke index (r = .45, p < .05). These results seem to suggest that technical skill is a key factor in typical efforts requiring prolonged aerobic power.

  3. Validation of a new method for estimating VO2max based on VO2 reserve.

    Science.gov (United States)

    Swain, David P; Parrott, James A; Bennett, Anna R; Branch, J David; Dowling, Elizabeth A

    2004-08-01

    The American College of Sports Medicine's (ACSM) preferred method for estimating maximal oxygen consumption (VO2max) has been shown to overestimate VO2max, possibly due to the short length of the cycle ergometry stages. This study validates a new method that uses a final 6-min stage and that estimates VO2max from the relationship between heart rate reserve (HRR) and VO2 reserve. A cycle ergometry protocol was designed to elicit 65-75% HRR in the fifth and sixth minutes of the final stage. Maximal workload was estimated by dividing the workload of the final stage by %HRR. VO2max was then estimated using the ACSM metabolic equation for cycling. After the 6-min stage was completed, an incremental test to maximal effort was used to measure actual VO2max. Forty-nine subjects completed a pilot study using one protocol to reach the 6-min stage, and 50 additional subjects completed a modified protocol. The pilot study obtained a valid estimate of VO2max (r = 0.91, SEE = 3.4 mL x min(-1) x kg-1) with no over- or underestimation (mean estimated VO2max = 35.3 mL x min(-1) x kg(-1), mean measured VO2max = 36.1 mL x min(-1) x kg(-1)), but the average %HRR achieved in the 6-min stage was 78%, with several subjects attaining heart rates considered too high for submaximal fitness testing. The second study also obtained a valid estimate of VO2max (r = 0.89, SEE = 4.0 mL x min(-1) x kg(-1)) with no over- or underestimation (mean estimated VO2max = 36.7 mL x min(-1) x kg(-1), mean measured VO2max = 36.9 mL x min(-1) x kg(-1), and the average %HRR achieved in the 6-min stage was 64%. A new method for estimating VO2max from submaximal cycling based on VO2 reserve has been found to be valid and more accurate than previous methods.

  4. Predicting maximal aerobic capacity (VO2max) from the critical velocity test in female collegiate rowers.

    Science.gov (United States)

    Kendall, Kristina L; Fukuda, David H; Smith, Abbie E; Cramer, Joel T; Stout, Jeffrey R

    2012-03-01

    The objective of this study was to examine the relationship between the critical velocity (CV) test and maximal oxygen consumption (VO2max) and develop a regression equation to predict VO2max based on the CV test in female collegiate rowers. Thirty-five female (mean ± SD; age, 19.38 ± 1.3 years; height, 170.27 ± 6.07 cm; body mass, 69.58 ± 0.3 1 kg) collegiate rowers performed 2 incremental VO2max tests to volitional exhaustion on a Concept II Model D rowing ergometer to determine VO2max. After a 72-hour rest period, each rower completed 4 time trials at varying distances for the determination of CV and anaerobic rowing capacity (ARC). A positive correlation was observed between CV and absolute VO2max (r = 0.775, p < 0.001) and ARC and absolute VO2max (r = 0.414, p = 0.040). Based on the significant correlation analysis, a linear regression equation was developed to predict the absolute VO2max from CV and ARC (absolute VO2max = 1.579[CV] + 0.008[ARC] - 3.838; standard error of the estimate [SEE] = 0.192 L·min(-1)). Cross validation analyses were performed using an independent sample of 10 rowers. There was no significant difference between the mean predicted VO2max (3.02 L·min(-1)) and the observed VO2max (3.10 L·min(-1)). The constant error, SEE and validity coefficient (r) were 0.076 L·min(-1), 0.144 L·min(-1), and 0.72, respectively. The total error value was 0.155 L·min(-1). The positive relationship between CV, ARC, and VO2max suggests that the CV test may be a practical alternative to measuring the maximal oxygen uptake in the absence of a metabolic cart. Additional studies are needed to validate the regression equation using a larger sample size and different populations (junior- and senior-level female rowers) and to determine the accuracy of the equation in tracking changes after a training intervention.

  5. Inverse relationship between VO2max and economy/efficiency in world-class cyclists.

    Science.gov (United States)

    Lucía, Alejandro; Hoyos, Jesus; Pérez, Margarita; Santalla, Alfredo; Chicharro, José L

    2002-12-01

    To determine the relationship that exists between VO2max and cycling economy/efficiency during intense, submaximal exercise in world-class road professional cyclists. METHODS Each of 11 male cyclists (26+/-1 yr (mean +/- SEM); VO2max: 72.0 +/- 1.8 mL x kg(-1) x min(-1)) performed: 1) a ramp test for O2max determination and 2) a constant-load test of 20-min duration at the power output eliciting 80% of subjects' VO2max during the previous ramp test (mean power output of 385 +/- 7 W). Cycling economy (CE) and gross mechanical efficiency (GE) were calculated during the constant-load tests. CE and GE averaged 85.2 +/- 2.3 W x L(-1) x min(-1) and 24.5 +/- 0.7%, respectively. An inverse, significant correlation was found between 1) VO2max (mL x kg(-0.32) x min(-1)) and both CE (r = -0.71; P = 0.01) and GE (-0.72; P = 0.01), and 2) VO2max (mL x kg(-1) x min(-1)) and both CE (r = -0.65; P = 0.03) and GE (-0.64; P = 0.03). A high CE/GE seems to compensate for a relatively low VO2max in professional cyclists.

  6. Influence of work-interval intensity and duration on time spent at a high percentage of VO2max during intermittent supramaximal exercise.

    Science.gov (United States)

    Wakefield, Benjamin R; Glaister, Mark

    2009-12-01

    The purpose of this study was to examine the effect of work-interval duration (WID) and intensity on the time spent at, or above, 95% VO2max (T95 VO2max) during intermittent bouts of supramaximal exercise. Over a 5-week period, 7 physically active men with a mean (+/-SD) age, height, body mass, and VO2max of 22 +/- 5 years, 181.5 +/- 5.6 cm, 86.4 +/- 11.4 kg, and 51.5 +/- 1.5 ml.kg-1.min-1, respectively, attended 7 testing sessions. After completing a submaximal incremental test on a treadmill to identify individual oxygen uptake/running velocity relationships, subjects completed a maximal incremental test to exhaustion to VO2max and subsequently (from the aforementioned relationship) the minimum velocity required to elicit VO2max (vVO2max). In a random order, subjects then carried out 3 intermittent runs to exhaustion at both 105% and 115% vVO2max. Each test used a different WID (20 s, 25 s, or 30 s) interspersed with 20-second passive recovery periods. Results revealed no significant difference in T95 vVO2max for intermittent runs at 105% versus 115% vVO2max (p = 0.142). There was, however, a significant effect (p VO2max, with WIDs of 30 seconds enabling more time relative to WIDs of 20 seconds (p = 0.018) and 25 seconds (p = 0.009). Moreover, there was an interaction between intensity and duration such that the effect of WID was magnified at the lower exercise intensity (p = 0.046). In conclusion, despite a number of limitations, the results of this investigation suggest that exercise intensities of approximately 105% vVO2max combined with WIDs greater than 25 seconds provide the best way of optimizing T95 VO2max when using fixed 20-second stationary rest periods.

  7. Steady exercise removes VO(2max) difference between mitochondrial genomic variants.

    Science.gov (United States)

    Marcuello, Ana; Martínez-Redondo, Diana; Dahmani, Yahya; Terreros, José L; Aragonés, Teresa; Casajús, José A; Echavarri, José M; Quílez, Julia; Montoya, Julio; López-Pérez, Manuel J; Díez-Sánchez, Carmen

    2009-09-01

    It has been clearly established that mitochondrial variants, among other potential factors, influence on VO(2max). With this study we sought to determine whether this genetic predisposition could be modified by steady exercise. Mitochondrial genetic variants were determined in 70 healthy controls (CON) and in 77 athletes who trained regularly (50 cyclists, aerobic training (AER), and 27 runners of 400m, anaerobic training (NoAER)). All of them were male Spanish Caucasian individuals. A maximum graded exercise test (GXT) in cycle-ergometer was performed to determine VO(2max) (mL kg(-1)min(-1)). Our results confirmed that, in CON, VO(2max) (P=0.007) was higher in Non-J than J individuals. Furthermore, we found that AER and NoAER showed, as it could be expected, higher VO(2max) than CON, but not differences between mitochondrial variants have been found. According with these findings, the influence of mitochondrial DNA (mtDNA) variants on VO(2max) has been confirmed, and a new conclusion has arisen: the steady exercise is able to remove this influence. The interest of these promising findings in muscular performance should be further explored, in particular, the understanding of potential applications in sport training and in muscle pathological syndromes.

  8. Prior Knowledge of Trial Number Influences the Incidence of Plateau at VO2max.

    Science.gov (United States)

    Gordon, Dan; Caddy, Oliver; Merzbach, Viviane; Gernigon, Marie; Baker, James; Scruton, Adrian; Keiller, Don; Barnes, Richard

    2015-03-01

    The purpose of this study was to assess the VO2max plateau response at VO2max during a series of pre-determined trials. Ten male well-trained athletes (age, 23.0 ± 3.2; height, 183.3 ± 5.5 cm; mass 77.5 ± 11.1 Kg; VO2max 66.5 ± 5.0 ml(.)kg(-1,)min(-1)), but who were VO2max testing naïve and with prior-knowledge of trial number completed four incremental tests to volitional exhaustion, separated by ~72-h for the determination of VO2max and gas exchange threshold. Throughout all trials VO2max was recorded on a breath-by-breath basis using a pre-calibrated metabolic cart, using a plateau criterion of Δ VO2 ≤1.5 ml(.)kg(-1.)min(-1) over the final 2 consecutive 30 s sampling periods. A significant difference was observed between trial-1 and trial-4 for plateau incidence (p = 0.0285) rising from 20% in trial-1 to a 70% response rate in trial-4. Furthermore a significant difference was observed for VO2dif (difference between criterion value and Δ VO2) in trial-1, 1.02 ± 1.69 ml(.)kg(-1.)min(-1) (p = 0.038), with non-significant differences observed for all other trials, despite a non-significant difference for VO2max across all trials (p > 0.05). Finally, a significant difference was observed for effort perception (RPE) at volitional exhaustion between trial-1 (17.7 ± 1.3) and trial-4 (19.0 ± 1.4) (p = 0.0052). These data indicate that prior-knowledge of trial number can influence the manifestation of the VO2 plateau in a group of well-trained male athletes, thereby suggesting that a form of effort control is established in order to preserve the finite anaerobic capacity. Key pointsIn well-trained athletes the incidence of plateau at VO2max increases in conjunction with an increase in trial number and the associated sensations of pain and fatigue.By informing the participant of the number of trials to be completed a closed-loop condition is developed whereby effort in all trials is compared to a perceptually developed template.Closed-loop condition leads to a

  9. The Effect of Habitual Smoking on VO2max

    Science.gov (United States)

    Wier, Larry T.; Suminski, Richard R.; Poston, Walker S.; Randles, Anthony M.; Arenare, Brian; Jackson, Andrew S.

    2008-01-01

    VO2max is associated with many factors, including age, gender, physical activity, and body composition. It is popularly believed that habitual smoking lowers aerobic fitness. PURPOSE: to determine the effect of habitual smoking on VO2max after controlling for age, gender, activity and BMI. METHODS: 2374 men and 375 women employed at the NASA/Johnson Space Center were measured for VO2max by indirect calorimetry (RER>=1.1), activity by the 11 point (0-10) NASA Physical Activity Status Scale (PASS), BMI and smoking pack-yrs (packs day*y of smoking). Age was recorded in years and gender was coded as M=1, W=0. Pack.y was made a categorical variable consisting of four levels as follows: Never Smoked (0), Light (1-10), Regular (11-20), Heavy (>20). Group differences were verified by ANOVA. A General Linear Models (GLM) was used to develop two models to examine the relationship of smoking behavior on VO2max. GLM #1(without smoking) determined the combined effects of age, gender, PASS and BMI on VO2max. GLM #2 (with smoking) determined the added effects of smoking (pack.y groupings) on VO2max after controlling for age, gender, PASS and BMI. Constant errors (CE) were calculated to compare the accuracy of the two models for estimating the VO2max of the smoking subgroups. RESULTS: ANOVA affirmed the mean VO2max of each pack.y grouping decreased significantly (psmoking exposure increased. GLM #1 showed that age, gender, PASS and BMI were independently related with VO2max (R2 = 0.642, SEE = 4.90, pSmoked, the effects on VO2max from Light and Regular smoking habits were -0.83 and -0.85 ml.kg- 1.min-1 respectively (peffect of Heavy smoking on VO2max was -2.56 ml.kg- 1.min-1 (psmoking group in GLM #2 was smaller than the CE s of the smoking group counterparts in GLM #1. CONCLUSIONS: After accounting for the effects of gender, age, PASS and BMI the effect of habitual smoking on reducing VO2max is minimal, about 0.85 ml/kg/min, until the habit exceeds 20 pack.y at which point an

  10. Factors determining the time course of VO2(max) decay during bedrest: implications for VO2(max) limitation.

    Science.gov (United States)

    Capelli, C; Antonutto, G; Kenfack, M Azabji; Cautero, M; Lador, F; Moia, C; Tam, E; Ferretti, G

    2006-09-01

    The aim of this study was to characterize the time course of maximal oxygen consumption VO2(max) changes during bedrests longer than 30 days, on the hypothesis that the decrease in VO2(max) tends to asymptote. On a total of 26 subjects who participated in one of three bedrest campaigns without countermeasures, lasting 14, 42 and 90 days, respectively, VO2(max) maximal cardiac output (Qmax) and maximal systemic O2 delivery (QaO2max) were measured. After all periods of HDT, VO2max, Qmax, and QaO2max were significantly lower than before. The VO2max decreased less than qmax after the two shortest bedrests, but its per cent decay was about 10% larger than that of Qmax after 90-day bedrest. The VO2max decrease after 90-day bedrest was larger than after 42- and 14-day bedrests, where it was similar. The Qmax and QaO2max declines after 90-day bedrest was equal to those after 14- and 42-day bedrest. The average daily rates of the VO2max, Qmax, and QaO2max decay during bedrest were less if the bedrest duration were longer, with the exception of that of VO2max in the longest bedrest. The asymptotic VO2max decay demonstrates the possibility that humans could keep working effectively even after an extremely long time in microgravity. Two components in the VO2max decrease were identified, which we postulate were related to cardiovascular deconditioning and to impairment of peripheral gas exchanges due to a possible muscle function deterioration.

  11. VO2 Max in Variable Type Exercise Among Well-Trained Upper Body Athletes.

    Science.gov (United States)

    Seals, Douglas R.; Mullin, John P.

    1982-01-01

    The maximal oxygen consumption (VO2 max) of well-trained upper body athletes was compared to that of untrained individuals in four types of exercise: arm cranking, legs only cycling, graded treadmill running, and combined arm cranking and leg cycling. Results of the study showed that well-trained upper body athletes attained a significantly higher…

  12. Prior Knowledge of Trial Number Influences the Incidence of Plateau at VO2max

    Directory of Open Access Journals (Sweden)

    Dan Gordon

    2015-01-01

    Full Text Available The purpose of this study was to assess the VO2max plateau response at VO2max during a series of pre-determined trials. METHODS: Ten male well-trained athletes (age, 23.0 ± 3.2; height, 183.3 ± 5.5 cm; mass 77.5 ± 11.1 Kg; VO2max 66.5 ± 5.0 ml.kg-1,min-1, but who were VO2max testing naïve and with prior-knowledge of trial number completed four incremental tests to volitional exhaustion, separated by ~72-h for the determination of VO2max and gas exchange threshold. Throughout all trials VO2max was recorded on a breath-by-breath basis using a pre-calibrated metabolic cart, using a plateau criterion of Δ VO2 ≤1.5 ml.kg-1.min-1 over the final 2 consecutive 30 s sampling periods. A significant difference was observed between trial-1 and trial-4 for plateau incidence (p = 0.0285 rising from 20% in trial-1 to a 70% response rate in trial-4. Furthermore a significant difference was observed for VO2dif (difference between criterion value and Δ VO2 in trial-1, 1.02 ± 1.69 ml.kg-1.min-1 (p = 0.038, with non-significant differences observed for all other trials, despite a non-significant difference for VO2max across all trials (p > 0.05. Finally, a significant difference was observed for effort perception (RPE at volitional exhaustion between trial-1 (17.7 ± 1.3 and trial-4 (19.0 ± 1.4 (p = 0.0052. These data indicate that prior-knowledge of trial number can influence the manifestation of the VO2 plateau in a group of well-trained male athletes, thereby suggesting that a form of effort control is established in order to preserve the finite anaerobic capacity.

  13. STUDY OF VO 2 MAX DURING PHASES OF MENSTRUATION IN YOUNG FEMALE ATHLETES

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    Sunitha

    2013-06-01

    Full Text Available ABSTRACT: Context: The menstrual cycle is a natural monthly event in y oung women, coordinated by the hypothalamic-pituitary ovarian axis and may influence physiological and pathological changes that occur throughout the life time of the woman. There is a cyclical change in sex hormones during the course of menstrual cycle that have the potential effects on exercise capacity and performance through numerous mechanisms, such a s substrate metabolism, cardiorespiratory function, thermoregulation, psychological factors a nd injuries. Consequently hormone level changes may theoretically lead to either improved or decrea sed performance at various times throughout the menstrual cycle. Physiological indices such as heart rate, tension, VO 2 max and aerobic power are of the main indicators of exercise performance, a potential change in these indices over the menstrual cycle will have large practical implicati ons for female athletes. VO 2 max is highly predictive of endurance performance, hence the pres ent study was done to evaluate whether there is any changes in the VO 2 max during phases of menstruation in young female athletes. Aim: The present study was done to evaluate the VO 2 max during phases of menstruation in young female athletes. Settings and Design: The present study was a cross sectional study consi sting of 30 healthy female athletes of 17-20 years of age. Materials and Methods: This study was conducted in the Department of Physiology, Adichunchanagiri inst itute of medical sciences after the institutional ethical clearance and written consent from each par ticipant. VO 2 max (maximum oxygen uptake was indirectly assessed by the Astrand nomogram met hod from submaximal exercise data obtained using Harvard step test during all the three phases of menstrual cycle. Results: The parameters were analyzed for statistical significance using St udents‘t’ test and p<0.05 was considered the level of significance. There were no significant

  14. Supramaximal testing to confirm attainment of VO2max in sedentary men and women.

    Science.gov (United States)

    Astorino, T A; White, A C; Dalleck, L C

    2009-04-01

    Supramaximal testing is widely used to verify VO2max attainment, yet its efficacy in sedentary subjects is unknown. The aim of the study was to test this hypothesis in men and women completing maximal cycle ergometry. Fifteen sedentary subjects (age=22.4+/-3.9 year) completed incremental exercise, and returned at least 24 h later to complete constant load exercise at 105% peak work rate (Wmax). Another group of nine sedentary men and women (age=21.8+/-5 year) completed supramaximal exercise at 115% Wmax 1-1.5 h after incremental exercise. During exercise, gas exchange data and heart rate (HR) were continuously obtained. VO2max was similar (p>0.05) between incremental and supramaximal exercise in subjects in the first (32.32+/-4.81 mL/kg/min vs. 31.80+/-5.35 mL/kg/min) and second subset (40.63+/-3.61 mL/kg/min vs. 41.66+/-5.55 mL/kg/min). Maximal HR was lower (pTest-retest reliability (r=0.81-0.89, pVO2max was high during repeated bouts of supramaximal testing. Findings support use of this protocol to confirm VO2max attainment in healthy, sedentary men and women completing incremental cycle ergometry.

  15. Validation of a Ramp Running Protocol for Determination of the True VO2max in Mice

    Science.gov (United States)

    Ayachi, Mohamed; Niel, Romain; Momken, Iman; Billat, Véronique L.; Mille-Hamard, Laurence

    2016-01-01

    In the field of comparative physiology, it remains to be established whether the concept of VO2max is valid in the mouse and, if so, how this value can be accurately determined. In humans, VO2max is generally considered to correspond to the plateau observed when VO2 no longer rises with an increase in workload. In contrast, the concept of VO2peak tends to be used in murine studies. The objectives of the present study were to determine whether (i) a continuous ramp protocol yielded a higher VO2peak than a stepwise, incremental protocol, and (ii) the VO2peak measured in the ramp protocol corresponded to VO2max. The three protocols (based on intensity-controlled treadmill running until exhaustion with eight female FVB/N mice) were performed in random order: (a) an incremental protocol that begins at 10 m.min−1 speed and increases by 3 m.min−1 every 3 min. (b) a ramp protocol with slow acceleration (3 m.min−2), and (c) a ramp protocol with fast acceleration (12 m.min−2). Each protocol was performed with two slopes (0 and 25°). Hence, each mouse performed six exercise tests. We found that the value of VO2peak was protocol-dependent (p VO2max plateau was associated with the fulfillment of two secondary criteria (a blood lactate concentration >8 mmol.l−1 and a respiratory exchange ratio >1). The total duration of the 3 m.min−2 0° ramp protocol was shorter than that of the incremental protocol. Taken as a whole, our results suggest that VO2max in the mouse is best determined by applying a ramp exercise protocol with slow acceleration and no treadmill slope. PMID:27621709

  16. Modality determines VO2max achieved in self-paced exercise tests: validation with the Bruce protocol.

    Science.gov (United States)

    Hanson, Nicholas J; Scheadler, Cory M; Lee, Taylor L; Neuenfeldt, Noah C; Michael, Timothy J; Miller, Michael G

    2016-07-01

    The Bruce protocol is traditionally used to assess maximal cardiorespiratory fitness (VO2max), but may have limitations, such as an unknown duration and large work rate increases. The use of self-paced VO2max tests (SPVs) may be beneficial if they are able to elicit similar maximal values in a set period of time. In addition, differences in modality between SPVs have not been explored. The purpose of this study was to compare SPVs, utilizing two different modes, with the Bruce (treadmill) protocol. Thirteen healthy, recreationally active individuals (eight men, five women) volunteered and participated in three different laboratory visits with each utilizing a different VO2max testing protocol. The first visit consisted of the Bruce protocol test, and the remaining visits entailed a maximal SPV on a treadmill (TM SPV) and a cycle ergometer (CE SPV). There were no differences in VO2max values between the TM SPV and the Bruce protocol tests (55.6 ± 4.9 vs. 56.2 ± 6.8, respectively; p = .510). As expected, the CE SPV (48.3 ± 7.6) was significantly lower than the other two tests (p VO2max as the Bruce protocol and did so with less incline and in less time suggesting that there are no changes in the limits of VO2max even when the test is self-paced and perceptually regulated.

  17. Accuracy of VO2(max) prediction equations in older adults.

    Science.gov (United States)

    Peterson, Matthew J; Pieper, Carl F; Morey, Miram C

    2003-01-01

    We explored the accuracy and bias of prediction equations (ACSM and Foster) in older, deconditioned men and women. We also examined the predictors of VO2(max) to further understand which variables affect respiratory fitness in the elderly. One hundred seventy-one community dwelling, men (72.6 +/- 4.8 yr) and women (71.0 +/- 5.1 yr) screened in a clinical trial were retrospectively examined. VO2(max) was measured using a standardized protocol with gas exchange measured. Measured VO2 (max) values were compared with prediction equations via mean difference analyses, and bias was explored using Bland-Altman analyses. Regression analysis determined significant predictors of measured VO2 (max). Alpha was PVO2 (max), 21.7 +/- 4.8 and 17.3 +/- 4.0, respectively. ACSM overestimated VO2 (max) in men and women, 26.3 +/- 8.2 and 20.9 +/- 7.3, respectively. By using Bland-Altman plots, ACSM showed significant overestimation bias in more fit women (r = 0.29), whereas Foster showed no estimation bias in either gender. Significant predictors of VO2 (max) were gender, BMI, age, treadmill grade, and speed, with an equation R(2) of 0.70. A measure of current activity levels did not make it into the final model ( P= 0.0505) but is worthy of future consideration using more sensitive measures than ours. ACSM is not appropriate for use when treadmill testing older adults. We believe the Foster equation's VO2 (max) prediction accuracy is acceptable, showing no bias along a continuum of aerobic capacity.

  18. The influence of exercise duration at VO2 max on the off-transient pulmonary oxygen uptake phase during high intensity running activity.

    Science.gov (United States)

    Billat, V L; Hamard, L; Koralsztein, J P

    2002-12-01

    The purpose of this study was to examine the influence of time run at maximal oxygen uptake (VO2 max) on the off-transient pulmonary oxygen uptake phase after supra-lactate threshold runs. We hypothesised: 1) that among the velocities eliciting VO2 max there is a velocity threshold from which there is a slow component in the VO2-off transient, and 2) that at this velocity the longer the duration of this time at VO2 max (associated with an accumulated oxygen kinetics since VO2 can not overlap VO2 max), the longer is the off-transient phase of oxygen uptake kinetics. Nine long-distance runners performed five maximal tests on a synthetic track (400 m) while breathing through the COSMED K4b2 portable, telemetric metabolic analyser: i) an incremental test which determined VO2 max, the minimal velocity associated with VO2 max (vVO2 max) and the velocity at the lactate threshold (vLT), ii) and in a random order, four supra-lactate threshold runs performed until exhaustion at vLT + 25, 50, 75 and 100% of the difference between vLT and vVO2 max (vdelta25, vdelta50, vdelta75, vdelta100). At vdelta25, vdelta50 (= 91.0 +/- 0.9% vVO2 max) and vdelta75, an asymmetry was found between the VO2 on (double exponential) and off-transient (mono exponential) phases. Only at vdelta75 there was at positive relationship between the time run at VO2 max (%tlimtot) and the VO2 recovery time constant (Z = 1.8, P = 0.05). In conclusion, this study showed that among the velocities eliciting VO2 max, vdelta75 is the velocity at which the longer the duration of the time at VO2 max, the longer is the off-transient phase of oxygen uptake kinetics. It may be possible that at vdelta50 there is not an accumulated oxygen deficit during the plateau of VO2 at VO2 max and that the duration of the time at VO2 max during the exhaustive runs at vdelta100, could be too short to induce an accumulating oxygen deficit affecting the oxygen recovery.

  19. THE RELATIONSHIP BETWEEN AEROBIC POWER AND REPEATED SPRINT ABILITY IN YOUNG SOCCER PLAYERS WITH DIFFERENT LEVELS OF VO2 MAX

    Directory of Open Access Journals (Sweden)

    Rostam Alizadeh

    2010-06-01

    Full Text Available In some team sports such as soccer which is interval, athletes need to prepare themselves immediatelyfor the next activity. Therefore it is very important to have enough information on characteristics of recovery phase and quick recovery to the first situation and to have the minimum speed reduction. The purpose of this study was to determine the relationship between aerobic power and repeated sprint ability (RSA or decrementindex in young soccer players in three different levels of Vo2max. Methods: For this reason 41 volunteers were divided in to three groups with different levels of Vo2max ml.kg-1.min-1 low 37.22 ± 2.3 (n= 18, age 17.1 ± 0.9 year, height 170.6 ± 0.76 cm, weight 67.1 ± 5.05 kg medium 46.46± 1.97 ml.kg-1.min-1 (n= 13, age 17.6± 0.76year, height 173.8 ± 4.84 cm, weight 65.9 ± 4.92 kg and high 55.63 ± 1.52 ml.kg-1.min-1 (n=10, age 17.4 ±0.69 year, height 177 ± 3.23 cm, weight 71.4 ± 3.94 kg. To determine Vo2max a graded exercise test until volitional exhaustion on treadmill was used, and also RAST was used to measure RSA. The lactate accumulation was measured before and after RSA protocol. Pearson's correlation was used to determine the correlation between the aerobic power and RSA. The results indicated that there are significant relationship between Vo2max anddecremental index in low Vo2max group (r= 0.86, p= 0.001, no significant relationship medium Vo2max group (r= 0.14, p= 0.63 and negative significant relationship in high Vo2max group (r= - 0.64, p= 0.04. There are no significant relationship between Lactate accumulation and decremental index in medium (r= 0.005, p= 0.98 and high Vo2max groups (r=0.27, p= 0.45. Discussion: It is possible that the recovery of inter muscular resources relates to aerobic ability, but there are other factors effective in RSA rather than Vo2max and Lactate accumulation. The current study showed a normal curved relationship between Vo2max and RSA.

  20. Biology of VO2 max: looking under the physiology lamp.

    Science.gov (United States)

    Lundby, C; Montero, D; Joyner, M

    2017-06-01

    In this review, we argue that several key features of maximal oxygen uptake (VO2 max) should underpin discussions about the biological and reductionist determinants of its interindividual variability: (i) training-induced increases in VO2 max are largely facilitated by expansion of red blood cell volume and an associated improvement in stroke volume, which also adapts independent of changes in red blood cell volume. These general concepts are also informed by cross-sectional studies in athletes that have very high values for VO2 max. Therefore, (ii) variations in VO2 max improvements with exercise training are also likely related to variations in these physiological determinants. (iii) All previously untrained individuals will respond to endurance exercise training in terms of improvements in VO2 max provided the stimulus exceeds a certain volume and/or intensity. Thus, genetic analysis and/or reductionist studies performed to understand or predict such variations might focus specifically on DNA variants or other molecular phenomena of relevance to these physiological pathways. © 2016 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

  1. Submaximal treadmill test predicts VO2max in overweight children.

    Science.gov (United States)

    Nemeth, Blaise A; Carrel, Aaron L; Eickhoff, Jens; Clark, R Randall; Peterson, Susan E; Allen, David B

    2009-05-01

    To demonstrate the ability of a submaximal test to predict VO(2max) in overweight children. A total of 130 children, 11 to 14 years old, with body mass index >85 percentile for age and sex performed a submaximal walking test. VO(2max) was measured by using open circuit spirometry during a graded exercise test to volitional fatigue. An equation to predict VO(2max) was modeled by using the variables of sex, weight (kg), height (cm), heart rate (HR) after 4 minutes during the submaximal test (4minHR), HR difference (4minHR - resting HR), and submaximal treadmill speed (miles per hour [mph]) in 75% of the subjects. Validation was performed by using the remaining 25% of subjects. A total of 113 subjects achieved a maximal effort and was used in the statistical analysis. Development and validation groups were similar in all aspects. On validation, the mean square error was 241.06 with the predicted VO(2max) within 10% of the observed value in 67% of subjects. VO(2max) was accurately predicted in this cohort of overweight children by using a submaximal, treadmill-based testing protocol.

  2. The ergogenic effect of recombinant human erythropoietin on VO2max depends on the severity of arterial hypoxemia.

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    Paul Robach

    Full Text Available Treatment with recombinant human erythropoietin (rhEpo induces a rise in blood oxygen-carrying capacity (CaO(2 that unequivocally enhances maximal oxygen uptake (VO(2max during exercise in normoxia, but not when exercise is carried out in severe acute hypoxia. This implies that there should be a threshold altitude at which VO(2max is less dependent on CaO(2. To ascertain which are the mechanisms explaining the interactions between hypoxia, CaO(2 and VO(2max we measured systemic and leg O(2 transport and utilization during incremental exercise to exhaustion in normoxia and with different degrees of acute hypoxia in eight rhEpo-treated subjects. Following prolonged rhEpo treatment, the gain in systemic VO(2max observed in normoxia (6-7% persisted during mild hypoxia (8% at inspired O(2 fraction (F(IO(2 of 0.173 and was even larger during moderate hypoxia (14-17% at F(IO(2 = 0.153-0.134. When hypoxia was further augmented to F(IO(2 = 0.115, there was no rhEpo-induced enhancement of systemic VO(2max or peak leg VO(2. The mechanism highlighted by our data is that besides its strong influence on CaO(2, rhEpo was found to enhance leg VO(2max in normoxia through a preferential redistribution of cardiac output toward the exercising legs, whereas this advantageous effect disappeared during severe hypoxia, leaving augmented CaO(2 alone insufficient for improving peak leg O(2 delivery and VO(2. Finally, that VO(2max was largely dependent on CaO(2 during moderate hypoxia but became abruptly CaO(2-independent by slightly increasing the severity of hypoxia could be an indirect evidence of the appearance of central fatigue.

  3. Matching of Male and Female Subjects Using VO2 Max.

    Science.gov (United States)

    Cureton, Kirk J.

    1981-01-01

    The increasing use of various VO2 max expressions as test measures is a problem because the magnitude of sex difference varies considerably with each expression. A valid match of male and female test subjects would consider physical activity history and the amount of endurance exercise done in the previous year. (Author/FG)

  4. Individual versus Standardized Running Protocols in the Determination of VO2max

    Directory of Open Access Journals (Sweden)

    Paula F. Sperlich, Hans-Christer Holmberg, Jennifer L. Reed, Christoph Zinner, Joachim Mester, Billy Sperlich

    2015-06-01

    Full Text Available The purpose of this study was to determine whether an individually designed incremental exercise protocol results in greater rates of oxygen uptake (VO2max than standardized testing. Fourteen well-trained, male runners performed five incremental protocols in randomized order to measure their VO2max: i an incremental test (INCS+I with pre-defined increases in speed (2 min at 8.64 km·h−1, then a rise of 1.44 km·h−1 every 30 s up to 14.4 km·h−1 and thereafter inclination (0.5° every 30 s; ii an incremental test (INCI at constant speed (14.4 km·h−1 and increasing inclination (2° every 2 min from the initial 0°; iii an incremental test (INCS at constant inclination (0° and increasing speed (0.5 km·h−1 every 30 s from the initial 12.0 km·h−1; iv a graded exercise protocol (GXP at a 1° incline with increasing speed (initially 8.64 km·h−1 + 1.44 km·h−1 every 5 min; v an individual exercise protocol (INDXP in which the runner chose the inclination and speed. VO2max was lowest (-4.2% during the GXP (p = 0.01; d = 0.06-0.61 compared to all other tests. The highest rating of perceived exertion, heart rate, ventilation and end-exercise blood lactate concentration were similar between the different protocols (p < 0.05. The time to exhaustion ranged from 7 min 18 sec (INCS to 25 min 30 sec (GXP (p = 0.01.The VO2max attained by employing an individual treadmill protocol does not differ from the values derived from various standardized incremental protocols.

  5. Why is VO2 max after altitude acclimatization still reduced despite normalization of arterial O2 content?

    Science.gov (United States)

    Calbet, J A L; Boushel, R; Radegran, G; Sondergaard, H; Wagner, P D; Saltin, B

    2003-02-01

    Acute hypoxia (AH) reduces maximal O2 consumption (VO2 max), but after acclimatization, and despite increases in both hemoglobin concentration and arterial O2 saturation that can normalize arterial O2 concentration ([O2]), VO2 max remains low. To determine why, seven lowlanders were studied at VO2 max (cycle ergometry) at sea level (SL), after 9-10 wk at 5,260 m [chronic hypoxia (CH)], and 6 mo later at SL in AH (FiO2 = 0.105) equivalent to 5,260 m. Pulmonary and leg indexes of O2 transport were measured in each condition. Both cardiac output and leg blood flow were reduced by approximately 15% in both AH and CH (P VO2 max (4.1 +/- 0.3 l/min at SL) fell to 2.2 +/- 0.1 l/min in AH (P VO2 max after acclimatization despite normalization of arterial [O2] is explained by two circulatory effects of altitude: 1) failure of cardiac output to normalize and 2) preferential redistribution of cardiac output to nonexercising tissues. Oxygen transport from blood to muscle mitochondria, on the other hand, appears unaffected by CH.

  6. Development of a hockey-specific, skate-treadmill VO2 max protocol.

    Science.gov (United States)

    Dreger, R W; Quinney, H A

    1999-12-01

    The purpose of this study was to investigate a protocol for the determination of VO2 max utilizing a motor-driven skate treadmill (ST). On separate days, 6 male hockey players completed a ST and a cycle ergometer (BK) VO2 max protocol. The results showed no significant difference between the ST and BK protocols for relative (60.4 +/- 5.09 vs. 59.0 +/- 8.31 ml.kg-1.min-1) and absolute VO2 max values (4.51 +/- 0.50 vs. 4.39 +/- 0.59 L.min-1), respectively. Significantly higher HR max was recorded during the ST protocol (202.3 +/- 4.27 vs. 200.7 +/- 4.55 b.min-1) (p < 0.05). Peak VE and VT were nonsignificant between the two conditions. However, peak f was higher for the ST protocol (63.0 +/- 7.56 vs. 60.2 +/- 7.76 breath.min-1) (p < 0.05). Although the physiological response to both protocols was similar, the ST protocol replicates a hockey stride, which may provide more applicable information for the development of training programs.

  7. Fitness self-perception and Vo2max in firefighters.

    Science.gov (United States)

    Peate, W F; Lundergan, Linda; Johnson, Jerry J

    2002-06-01

    Firefighters work at maximal levels of exertion. Fitness for such duty requires adequate aerobic capacity (maximum oxygen consumption [Vo2max]). Aerobic fitness can both improve a worker's ability to perform and offer resistance to cardiopulmonary conditions. Inactive firefighters have a 90% greater risk of myocardial infarction than those who are aerobically fit. Participants (101 firefighters) completed a questionnaire that asked them to rank their fitness level from 0 to 7; e.g., Level 0 was low fitness: "I avoid walking or exertion, e.g., always use elevator, drive whenever possible." The level of activity rating increased to Level 7: "I run over 10 miles per week or spend 3 hours per week in comparable physical activity." Each participant then completed two measures of Vo2max: a 5-minute step test and a submaximal treadmill test. There was no association between the firefighters' self-perception of their level of fitness and their aerobic capacity as measured by either step test or submaximal treadmill. Because of the critical job demands of firefighting and the negative consequences of inadequate fitness and aerobic capacity, periodic aerobic capacity testing with individualized exercise prescriptions and work--community support may be advisable for all active-duty firefighters.

  8. Cycling efficiency and time to exhaustion are reduced after acute passive stretching administration.

    Science.gov (United States)

    Esposito, F; Cè, E; Limonta, E

    2012-12-01

    The aim of this study was to assess the effects of acute passive stretching on cycling efficiency during an exercise of heavy intensity. After maximum aerobic power (VO(2max)) assessment, nine active males (24 ± 5 years; stature 1.71 ± 0.09 m; body mass 69 ± 7 kg; mean ± standard deviation) performed tests at 85% of VO(2max) (W(85)) until exhaustion, with and without pre-exercise stretching. During the tests, we determined the gas exchange, metabolic and cardiorespiratory parameters. With stretching, no differences in VO(2max) occurred (3.64 ± 0.14 vs 3.66 ± 0.07 L/min for stretching and control, respectively). During W(85), pre-exercise stretching (i) decreased time to exhaustion (t(lim)) by 26% (Pstretching and control, respectively; Pstretching and control, respectively; Pstretching did not have an effect on VO(2max), t(lim) and e(net) during heavy constant load exercise were significantly affected. These results are suggestive of an impairment in cycling efficiency due to changes in muscle neural activation and viscoelastic characteristics induced by stretching.

  9. Monitoring changes in VO2max via the Polar FT40 in female collegiate soccer players.

    Science.gov (United States)

    Esco, Michael R; Snarr, Ronald L; Williford, Hank N

    2014-01-01

    This study was conducted to determine if the Polar FT40 could accurately track changes in maximal oxygen consumption (VO2max) in a group of female soccer players. Predicted VO2max (pVO2max) via the Polar FT40 and observed VO2max (aVO2max) from a maximal exercise test on a treadmill were determined for members of a collegiate soccer team (n = 20) before and following an 8-week endurance training protocol. Predicted (VO2max and aVO2max measures were compared at baseline and within 1 week post-training. Change values (i.e., the difference between pre to post) for each variable were also determined and compared. There was a significant difference in aVO2max (pre = 43.6 ± 2.4 ml · kg · min(-1), post = 46.2 ± 2.4 ml · kg · min(-1), P < 0.001) and pVO2max (pre = 47.3 ± 5.3 ml · kg · min(-1), post = 49.7 ± 6.2 ml · kg · min(-1), P = 0.009) following training. However, predicted values were significantly greater at each time point compared to observed values (P < 0.001 at pre and P = 0.008 at post). Furthermore, there was a weak correlation between the change in aVO2max and the change in pVO2max (r = 0.18, P = 0.45). The Polar FT40 does not appear to be a valid method for predicting changes in individual VO2max following 8 weeks of endurance training in female collegiate soccer players.

  10. Indirect estimation of VO2max in athletes by ACSM’s equation: valid or not?

    Science.gov (United States)

    Koutlianos, N; Dimitros, E; Metaxas, T; Cansiz, M; Deligiannis, AS; Kouidi, E

    2013-01-01

    Aim: The purpose of this study was to assess the indirect calculation of VO2max using ACSM’s equation for Bruce protocol in athletes of different sports and to compare with the directly measured; secondly to develop regression models predicting VO2 max in athletes. Methods: Fifty five male athletes of national and international level (mean age 28.3 ± 5.6 yrs) performed graded exercise test with direct measurement of VO2 through ergospirometric device. Moreover, 3 equations were used for the indirect calculation of VO2max: a) VO2max= (0.2 · Speed) + (0.9 · Speed · Grade) + 3.5 (ACSM running equation), b) regression analysis model using enter method and c) stepwise method based on the measured data of VO2. Age, BMI, speed, grade and exercise time were used as independent variables. Results: Regression analysis using enter method yielded the equation (R=.64, standard error of estimation [SEE] = 6.11): VO2max (ml·kg-1·min-1) = 58.443 - (0.215 · age) - (0.632 · BMI) - (68.639 · grade) + (1.579 · time) while stepwise method (R = .61, SEE = 6.18) led to: VO2max (ml·kg-1·min-1) = 33.971 - (0.291 · age) + (1.481 · time). The calculated values of VO2max from these regression models did not differ significantly from the measured VO2max (p>.05). On the contrary, VO2max calculated from the ACSM’s running equation was significantly higher from the actually measured value by 14.6% (p VO2max in athletes aged 18-37 years using Bruce protocol. Only the regression models were correlated moderately with the actually measured values of VO2max. PMID:24376318

  11. A longitudinal assessment of change in VO2max and maximal heart rate in master athletes.

    Science.gov (United States)

    Hawkins, S A; Marcell, T J; Victoria Jaque, S; Wiswell, R A

    2001-10-01

    The purpose of this study was to determine the longitudinal change in VO2max and HRmax in male and female master endurance runners and to compare these changes based upon gender, age, and change in training volume. Eighty-six male (53.9 +/- 1.1 yr) and 49 female (49.1 +/- 1.2 yr) master endurance runners were tested an average of 8.5 yr apart. Subjects were grouped by age at first visit, change in VO2max, and change in training volume. Measurements included body composition by hydrostatic weighing, maximal exercise testing on a treadmill, and training history by questionnaire. Data were analyzed by ANOVA and multiple regression. VO2max and HRmax declined significantly regardless of gender or age group (P VO2max by age group ranged from -1% to -4.6% per year for men and -0.5% to 2.4% per year for women. Men with the greatest loss in VO2max had the greatest loss in LBM (-2.8 +/- 0.7 kg), whereas women with the greatest loss in VO2max demonstrated the greatest change in training volume (-24.1 +/- 3.0 km.wk-1). Additionally, women with the greatest loss in VO2max (-9.6 +/- 2.6 mL.kg-1.min-1) did not replace estrogen after menopause independent of age. HRmax change did not differ by VO2max change or training volume change in either gender. In conclusion, these data suggest that VO2max declines in male and female master athletes at a rate similar to or greater than that expected in sedentary older adults. Additionally, these data suggest that maintenance of LBM and VO2max were associated in men, whereas in women, estrogen replacement and maintenance of training volume were associated with maintained VO2max.

  12. Indirect estimation of VO2max in athletes by ACSM's equation: valid or not?

    Science.gov (United States)

    Koutlianos, N; Dimitros, E; Metaxas, T; Cansiz, M; Deligiannis, As; Kouidi, E

    2013-04-01

    The purpose of this study was to assess the indirect calculation of VO2max using ACSM's equation for Bruce protocol in athletes of different sports and to compare with the directly measured; secondly to develop regression models predicting VO2 max in athletes. Fifty five male athletes of national and international level (mean age 28.3 ± 5.6 yrs) performed graded exercise test with direct measurement of VO2 through ergospirometric device. Moreover, 3 equations were used for the indirect calculation of VO2max: a) VO2max= (0.2 · Speed) + (0.9 · Speed · Grade) + 3.5 (ACSM running equation), b) regression analysis model using enter method and c) stepwise method based on the measured data of VO2. Age, BMI, speed, grade and exercise time were used as independent variables. Regression analysis using enter method yielded the equation (R=.64, standard error of estimation [SEE] = 6.11): VO2max (ml·kg(-1)·min(-1)) = 58.443 - (0.215 · age) - (0.632 · BMI) - (68.639 · grade) + (1.579 · time) while stepwise method (R = .61, SEE = 6.18) led to: VO2max (ml·kg(-1)·min(-1)) = 33.971 - (0.291 · age) + (1.481 · time). The calculated values of VO2max from these regression models did not differ significantly from the measured VO2max (p>.05). On the contrary, VO2max calculated from the ACSM's running equation was significantly higher from the actually measured value by 14.6% (p VO2max in athletes aged 18-37 years using Bruce protocol. Only the regression models were correlated moderately with the actually measured values of VO2max.

  13. A Study of VO2 Max and Body Fat Percentage in Female Athletes

    Science.gov (United States)

    Bute, Smita S; Deshmukh, P.R

    2014-01-01

    Introduction: Aerobic capacity of athletes is an important element of success in sports achievements. It is generally considered the best indicator of cardio respiratory endurance and athletic fitness. Body fat percentage affects VO2 max and thus the cardiovascular status of the athletes. The present study was undertaken to assess the VO2 max and body fat percentage in athletes. The secondary objective of the study was to study the relationship between VO2 max and body fat percentage. Materials and Methods: Twenty five female athletes of age group 17-22years were selected for the study. VO2 max was determined by Queen’s college step test and body fat percentage by skin fold calipers. The VO2 max and body fat percentage were determined in non athletes of same age group for comparison. The statistical analysis was done by Student’s t-test and Pearson correlation test. Observation and Results: The mean VO2 max in athletic group was 39.62 ± 2.80 ml/kg/min. In non-athletic group, VO2 max was 23.54 ± 3.26 ml/kg/min. The mean body fat percentage in athletes was 24.11 ± 1.83% and in non-athletes it was 29.31 ± 3.86%.The difference in VO2 max and body fat percentage was statistically significant in our study. The VO2 max and body fat percentage in both the groups showed negative correlation by Pearson test but, was not statistically significant. Conclusion: The present study showed a statistically significant higher VO2 max in female athletes. The study showed a negative correlation between VO2 max and body fat percentage but was not statistically significant. PMID:25653935

  14. Estimativa das contribuições dos sistemas anaeróbio lático e alático durante exercícios de cargas constantes em intensidades abaixo do VO2max Estimation of contributions of the anaerobic lactic and alactic systems during constant-load exercises at intensities below the VO2max

    Directory of Open Access Journals (Sweden)

    Marcos David Silva-Cavalcante

    2013-01-01

    Full Text Available O objetivo do estudo foi estimar as contribuições do metabolismo anaeróbio lático (MAL e alático (MAA em intensidades abaixo do consumo máximo de oxigênio (VO2max. Dez homens (23 ± 4 anos, 176,4 ± 6,8 cm, 72,4 ± 8,2 kg, 12,0 ± 4,5 % de gordura corporal realizaram um teste progressivo até a exaustão voluntária para identificação do VO2max, da potência correspondente ao VO2max (WVO2max e do segundo limiar ventilatório (LV2. Na segunda e na terceira visita foram realizados seis testes de cargas constantes (três testes por sessão com intensidades abaixo do VO2max. Houve uma predominância do MAL sobre o MAA durante os exercícios submáximos a partir da intensidade correspondente ao LV2, sendo significativamente maior em 90% VO2max (p The purpose this study was that estimated contributions of the anaerobic lactic (MAL and alactic (MAA metabolism during constant load exercises at intensities below the maximal oxygen capacity uptake (VO2max. Ten males (23 ± 4 years, 176.4 ± 6.8 cm, 72.4 ± 8.2 kg, 12.0 ± 4.5 % of fat body performed in the first visit a progressive test until exhaustion to identification of VO2max, power output corresponding to the VO2max (WVO2max and second ventilatory threshold (LV2. On the second and third visit, the participants performed six constant workload tests (3 per session with intensities below VO2max. There was a predominance of MAL about MAA during the exercises sub-maximal from intensity corresponding to the LV2, being significantly higher at 90% VO2max (p < 0.05. Thus, these results may help coaches to implement training loads appropriate to their athletes, according to the metabolic demand of the competition.

  15. Waist circumference and VO2max are associated with metabolic and hemostatic risk in premenopausal nurses

    NARCIS (Netherlands)

    Elich, H; Riese, H; De Geus, EJC

    In 21 nurses (34.4+/-3.9 yr), VO2max, physical activity, body composition and lifestyle parameters were measured to determine which of these characteristics are related to metabolic and hemostatic risk for cardiovascular disease. Physical activity was assessed with the 7-day recall interview VO2max

  16. Effect of Toe Clips During Bicycle Ergometry on VO2 max.

    Science.gov (United States)

    Moffat, Roger S.; Sparling, Phillip B.

    1985-01-01

    Eight men participated in three randomized maximal oxygen uptake tests to investigate the hypothesis that the use of toe clips on bicycle ergometers produced a higher VO2 max. No significant difference in mean VO2 max or performance time was observed. (Author/MT)

  17. Daily pattern of %VO2max and heart rates in normal and undernourished school children.

    Science.gov (United States)

    Spurr, G B; Reina, J C

    1990-10-01

    The pattern of usage of the VO2max, expressed as %VO2max during ordinary school days, with minute-by-minute heart rate recording, was studied in 106 boys and 83 girls, 6-16 yr of age divided into three age groups (6-8, 10-12, and 14-16 yr), living under economically deprived conditions in Colombia and classified as nutritionally normal or marginally malnourished. In a 12-h period, the 12 groups of children spent, on the average, 7-10 h at less than 30% VO2max, 1.5-4 h at 30-50% VO2max, and an accumulated time of 20-60 min above 50% VO2max. The latter occurred in short bursts rather than during sustained periods. There was a statistically significant but small decrease (approximately -3%) in the average 12 h %VO2max with age but no effects of sex or nutritional status. The overall average was about 25% VO2max in all groups. The data may suggest the existence of the regulation of physical activity to some level easily sustainable for long periods. Expressing the data as 30 min averages during 5 h of school and 5 h of free-time activity allows for the possibility of seeing group differences during shorter periods of time. This may prove useful in exercise training programs and studies of effort in the workplace.

  18. VO2 max is associated with ACE genotype in postmenopausal women.

    Science.gov (United States)

    Hagberg, J M; Ferrell, R E; McCole, S D; Wilund, K R; Moore, G E

    1998-11-01

    Relationships have frequently been found between angiotensin-converting enzyme (ACE) genotype and various pathological and physiological cardiovascular outcomes and functions. Thus we sought to determine whether ACE genotype affected maximal O2 consumption (VO2 max) and maximal exercise hemodynamics in postmenopausal women with different habitual physical activity levels. Age, body composition, and habitual physical activity levels did not differ among ACE genotype groups. However, ACE insertion/insertion (II) genotype carriers had a 6.3 ml . kg-1 . min-1 higher VO2 max (P VO2 max (P VO2 max than the DD genotype group, but the difference was not significant. ACE genotype accounted for 12% of the variation in VO2 max among women after accounting for the effect of habitual physical activity levels. The entire difference in VO2 max among ACE genotype groups was the result of differences in maximal arteriovenous O2 difference (a-vDO2). ACE genotype accounted for 17% of the variation in maximal a-vDO2 in these women. Maximal cardiac output index did not differ whatsoever among ACE genotype groups. Thus it appears that ACE genotype accounts for a significant portion of the interindividual differences in VO2 max among these women. However, this difference is the result of genotype-dependent differences in maximal a-vDO2 and not of maximal stroke volume and maximal cardiac output.

  19. A randomized controlled pilot study of VO2 max testing: a potential model for measuring relative in vivo efficacy of different red blood cell products.

    Science.gov (United States)

    Bennett-Guerrero, Elliott; Lockhart, Evelyn L; Bandarenko, Nicholas; Campbell, Mary L; Natoli, Michael J; Jamnik, Veronika K; Carter, Timothy R; Moon, Richard E

    2017-03-01

    Randomized trials, for example, RECESS, comparing "young" (median, 7-day) versus "middle-aged" (median, 28-day) red blood cells (RBCs), showed no difference in outcome. These data are important; however, they do not inform us about the safety and effectiveness of the oldest RBCs, which some patients receive. It may not be feasible to conduct a clinical trial randomizing patients to receive the oldest blood. Therefore, we propose strenuous exercise (VO2 max testing) as a model to study the relative efficacy to increase oxygen delivery to tissue of different RBC products, for example, extremes of storage duration. In this pilot study, eight healthy subjects had 2 units of leukoreduced RBCs collected by apheresis in AS-3 using standard methods. Subjects were randomized to receive both (2) units of their autologous RBCs at either 7 or 42 days after blood collection. VO2 max testing on a cycle ergometer was performed 2 days before (Monday) and 2 days after (Friday) the transfusion visit (Wednesday). This design avoids confounding effects on intravascular volume from the 2-unit blood transfusion. The primary outcome was the difference in VO2 max between Friday and Monday (delta VO2 max). VO2 max increased more in the 7-day RBC arm (8.7 ± 6.9% vs. 1.9 ± 6.5%, p = 0.202 for comparison between arms). Exercise duration (seconds) increased in the 7-day RBC arm (8.4 ± 1.7%) but actually decreased in the 42-day arm (-2.6 ± 3.6%, p = 0.002). This pilot study suggests that VO2 max testing has potential as a rigorous and quantitative in vivo functional assay of RBC function. Our preliminary results suggest that 42-day RBCs are inferior to 7-day RBCs at delivering oxygen to tissues. © 2016 AABB.

  20. Improved VO2max and time trial performance with more high aerobic intensity interval training and reduced training volume: a case study on an elite national cyclist.

    Science.gov (United States)

    Støren, Øyvind; Bratland-Sanda, Solfrid; Haave, Marius; Helgerud, Jan

    2012-10-01

    The present study investigated to what extent more high aerobic intensity interval training (HAIT) and reduced training volume would influence maximal oxygen uptake (VO2max) and time trial (TT) performance in an elite national cyclist in the preseason period. The cyclist was tested for VO2max, cycling economy (C(c)), and TT performance on an ergometer cycle during 1 year. Training was continuously logged using heart rate monitor during the entire period. Total monthly training volume was reduced in the 2011 preseason compared with the 2010 preseason, and 2 HAIT blocks (14 sessions in 9 days and 15 sessions in 10 days) were performed as running. Between the HAIT blocks, 3 HAIT sessions per week were performed as cycling. From November 2010 to February 2011, the cyclist reduced total average monthly training volume by 18% and cycling training volume by 60%. The amount of training at 90-95% HRpeak increased by 41%. VO2max increased by 10.3% on ergometer cycle. TT performance improved by 14.9%. C(c) did not change. In conclusion, preseason reduced total training volume but increased amount of HAIT improved VO2max and TT performance without any changes in C(c). These improvements on cycling appeared despite that the HAIT blocks were performed as running. Reduced training time, and training transfer from running into improved cycling form, may be beneficial for cyclists living in cold climate areas.

  1. Evidence of O2 supply-dependent VO2 max in the exercise-trained human quadriceps.

    Science.gov (United States)

    Richardson, R S; Grassi, B; Gavin, T P; Haseler, L J; Tagore, K; Roca, J; Wagner, P D

    1999-03-01

    Maximal O2 delivery and O2 uptake (VO2) per 100 g of active muscle mass are far greater during knee extensor (KE) than during cycle exercise: 73 and 60 ml. min-1. 100 g-1 (2.4 kg of muscle) (R. S. Richardson, D. R. Knight, D. C. Poole, S. S. Kurdak, M. C. Hogan, B. Grassi, and P. D. Wagner. Am. J. Physiol. 268 (Heart Circ. Physiol. 37): H1453-H1461, 1995) and 28 and 25 ml. min-1. 100 g-1 (7.5 kg of muscle) (D. R. Knight, W. Schaffartzik, H. J. Guy, R. Predilleto, M. C. Hogan, and P. D. Wagner. J. Appl. Physiol. 75: 2586-2593, 1993), respectively. Although this is evidence of muscle O2 supply dependence in itself, it raises the following question: With such high O2 delivery in KE, are the quadriceps still O2 supply dependent at maximal exercise? To answer this question, seven trained subjects performed maximum KE exercise in hypoxia [0.12 inspired O2 fraction (FIO2)], normoxia (0.21 FIO2), and hyperoxia (1.0 FIO2) in a balanced order. The protocol (after warm-up) was a square wave to a previously determined maximum work rate followed by incremental stages to ensure that a true maximum was achieved under each condition. Direct measures of arterial and venous blood O2 concentration in combination with a thermodilution blood flow technique allowed the determination of O2 delivery and muscle VO2. Maximal O2 delivery increased with inspired O2: 1.3 +/- 0.1, 1.6 +/- 0.2, and 1.9 +/- 0.2 l/min at 0.12, 0.21, and 1.0 FIO2, respectively (P VO2 (VO2 max): 1.04 +/- 0.13, 1. 24 +/- 0.16, and 1.45 +/- 0.19 l/min at 0.12, 0.21, and 1.0 FIO2, respectively (P VO2 max, supporting our previous finding that a decrease in O2 supply will proportionately decrease muscle VO2 max. As even in the isolated quadriceps (where normoxic O2 delivery is the highest recorded in humans) an increase in O2 supply by hyperoxia allows the achievement of a greater VO2 max, we conclude that, in normoxic conditions of isolated KE exercise, KE VO2 max in trained subjects is not limited by mitochondrial

  2. Effects of erythrocyte infusion on VO2max at high altitude

    DEFF Research Database (Denmark)

    Young, Jette Feveile; Sawka, M N; Muza, S R

    1996-01-01

    group received only saline. The VO2max of erythrocyte-infused [54 +/- 1 (SE) ml.kg-1.min-1] and control subjects (52 +/- 2 ml.kg-1.min-1) did not differ at SL before infusion. The decrement in VO2max on HA1 did not differ between groups, averaging 26% overall, despite higher (P arterial...... hematocrit, hemoglobin concentration, and arterial O2 content in the erythrocyte-infused subjects. By HA9, there were no longer any differences in hematocrit, hemoglobin concentration, or arterial O2 content between groups. No change in VO2max occurred between HA1 and HA9 for either group. Thus, despite...... increasing arterial O2-carrying capacity, autologous erythrocyte infusion did not ameliorate the decrement in VO2max at 4,300-m altitude....

  3. Patterns of Senescence in Human Cardiovascular Fitness: VO2max in Subsistence and Industrialized Populations

    Science.gov (United States)

    Pisor, Anne C.; Gurven, Michael; Blackwell, Aaron D.; Kaplan, Hillard; Yetish, Gandhi

    2014-01-01

    Objectives This study explores whether cardiovascular fitness levels and senescent decline are similar in the Tsimane of Bolivia and Canadians, as well as other subsistence and industrialized populations. Among Tsimane, we examine whether morbidity predicts lower levels and faster decline of cardiovascular fitness, or whether their lifestyle (e.g., high physical activity) promotes high levels and slow decline. Alternatively, high activity levels and morbidity might counterbalance such that Tsimane fitness levels and decline are similar to those in industrialized populations. Methods Maximal oxygen uptake (VO2max) was estimated using a step test heart rate method for 701 participants. We compared these estimates to the Canadian Health Measures Survey and previous studies in industrialized and subsistence populations. We evaluated whether health indicators and proxies for market integration were associated with VO2max levels and rate of decline for the Tsimane. Results The Tsimane have significantly higher levels of VO2max and slower rates of decline than Canadians; initial evidence suggests differences in VO2max levels between other subsistence and industrialized populations. Low hemoglobin predicts low VO2max for Tsimane women while helminth infection predicts high VO2max for Tsimane men, though results might be specific to the VO2max scaling parameter used. No variables tested interact with age to moderate decline. Conclusions The Tsimane demonstrate higher levels of cardiovascular fitness than industrialized populations, but levels similar to other subsistence populations. The high VO2max of Tsimane is consistent with their high physical activity and few indicators of cardiovascular disease, measured in previous studies. PMID:24022886

  4. A theoretical analysis of factors determining VO2 MAX at sea level and altitude.

    Science.gov (United States)

    Wagner, P D

    1996-12-01

    When maximal VO2 (VO2 MAX) is limited by O2 supply, it is generally thought that cardiac output (QT) is mostly responsible, but other O2 transport conductances [ventilation (VA); [Hb]; pulmonary (DLO2) and muscle (DMO2) diffusion capacities] may also influence VO2 MAX. A numerical analysis interactively linking the lungs, circulation and muscles was designed to compare the influences of each conductance component on VO2 MAX at three altitudes: PB = 760, 464 and 253 Torr. For any given set of conductances the analysis simultaneously solved six equations for alveolar, arterial, and venous PO2 and PcO2. The equations represent pulmonary mass balance, pulmonary diffusion, and muscle diffusion for both gases. At PB = 760, [Hb], DLO2 and DMO2 were as influential as QT in limiting VO2 MAX. With increasing altitude, the influence of QT and [Hb] fell while that of VA, DLO2 and DMO2 progressively increased until at PB = 253, VO2 MAX was independent of QT and [Hb]. Neither the fall in maximal QT nor rise in [Hb] with chronic hypoxia therefore appear to affect VO2 MAX. However, high values of ventilation, DLO2 and DMO2 appear to be advantageous for exercise at altitude.

  5. Reliability of treadmill measures and criteria to determine VO2max in prepubertal girls.

    Science.gov (United States)

    Figueroa-Colon, R; Hunter, G R; Mayo, M S; Aldridge, R A; Goran, M I; Weinsier, R L

    2000-04-01

    The main objective of this study was to determine the reliability of measuring treadmill exercise economy (VO2submax) and the maximal oxygen uptake (VO2max) in prepubertal girls tested twice, 6 wk apart. We also wanted to examine the percentage of young girls who were able to reach the criteria for achieving VO2max and to describe methods that would allow a high proportion of young children to achieve criteria for reaching a true VO2max. We studied 61 normal-weight, prepubertal girls with a mean (+/- SD) age 7.3+/-1.3 yr (range 4.8 to 10.3 yr). VO2submax was determined while walking for 4 min at 2.5 mph with 0% grade. VO2max was measured during a progressive, all-out, continuous treadmill test using standardized procedures and criteria. Heart rate (HR) was measured using a Polar monitor. Respiratory rate (RR), respiratory exchange ratio (RER), ventilation (V), and VO2 were measured using a Sensormedics metabolic monitor. There were no significant differences between visits I and 2 in mean HR, RR, RER, V, VO2submax (421 vs 422 mL x min(-1), respectively), and VO2max (1036 vs 1049 mL x min(-1), respectively). Intra-individual coefficients of variation (CV) between visits 1 and 2 for submaximal tests were: HR = 5.1%, RR = 12.4%, RER = 7.2%, V = 12.5%, and VO2 = 12.4%. Intra-individual CVs for the maximum tests were: HRmax = 2.1%, RRmax = 10.8%, RERmax = 5.3%, Vmax = 11.7%, and VO2max = 7.5%. A high proportion of the girls reached criteria for VO2max [RER> 1.00, HR>85% of age predicted maximum, and plateauing of VO2max] in both visits: 99% reached one of three criteria, 92% reached two of three criteria, and 70% reached all three criteria. Twenty girls [mean age 7.2+/-1.2 yr] reached at least two criteria in both visits, whereas 32 girls [mean (+/- SD) age 8.6+/-1.0 yr] reached three criteria in both visits. Exercise measurements using treadmill testing were reliable in healthy, normal-weight, prepubertal girls. Older girls when compared to the younger girls were able

  6. VO2max trainability and high intensity interval training in humans: a meta-analysis.

    Science.gov (United States)

    Bacon, Andrew P; Carter, Rickey E; Ogle, Eric A; Joyner, Michael J

    2013-01-01

    Endurance exercise training studies frequently show modest changes in VO2max with training and very limited responses in some subjects. By contrast, studies using interval training (IT) or combined IT and continuous training (CT) have reported mean increases in VO2max of up to ~1.0 L · min(-1). This raises questions about the role of exercise intensity and the trainability of VO2max. To address this topic we analyzed IT and IT/CT studies published in English from 1965-2012. Inclusion criteria were: 1)≥ 3 healthy sedentary/recreationally active humans training duration 6-13 weeks, 3) ≥ 3 days/week, 4) ≥ 10 minutes of high intensity work, 5) ≥ 1:1 work/rest ratio, and 6) results reported as mean ± SD or SE, ranges of change, or individual data. Due to heterogeneity (I(2) value of 70), statistical synthesis of the data used a random effects model. The summary statistic of interest was the change in VO2max. A total of 334 subjects (120 women) from 37 studies were identified. Participants were grouped into 40 distinct training groups, so the unit of analysis was 40 rather than 37. An increase in VO2max of 0.51 L · min(-1) (95% CI: 0.43 to 0.60 L · min(-1)) was observed. A subset of 9 studies, with 72 subjects, that featured longer intervals showed even larger (~0.8-0.9 L · min(-1)) changes in VO2max with evidence of a marked response in all subjects. These results suggest that ideas about trainability and VO2max should be further evaluated with standardized IT or IT/CT training programs.

  7. VO2max trainability and high intensity interval training in humans: a meta-analysis.

    Directory of Open Access Journals (Sweden)

    Andrew P Bacon

    Full Text Available Endurance exercise training studies frequently show modest changes in VO2max with training and very limited responses in some subjects. By contrast, studies using interval training (IT or combined IT and continuous training (CT have reported mean increases in VO2max of up to ~1.0 L · min(-1. This raises questions about the role of exercise intensity and the trainability of VO2max. To address this topic we analyzed IT and IT/CT studies published in English from 1965-2012. Inclusion criteria were: 1≥ 3 healthy sedentary/recreationally active humans <45 yrs old, 2 training duration 6-13 weeks, 3 ≥ 3 days/week, 4 ≥ 10 minutes of high intensity work, 5 ≥ 1:1 work/rest ratio, and 6 results reported as mean ± SD or SE, ranges of change, or individual data. Due to heterogeneity (I(2 value of 70, statistical synthesis of the data used a random effects model. The summary statistic of interest was the change in VO2max. A total of 334 subjects (120 women from 37 studies were identified. Participants were grouped into 40 distinct training groups, so the unit of analysis was 40 rather than 37. An increase in VO2max of 0.51 L · min(-1 (95% CI: 0.43 to 0.60 L · min(-1 was observed. A subset of 9 studies, with 72 subjects, that featured longer intervals showed even larger (~0.8-0.9 L · min(-1 changes in VO2max with evidence of a marked response in all subjects. These results suggest that ideas about trainability and VO2max should be further evaluated with standardized IT or IT/CT training programs.

  8. A comparison of two different shuttle run tests for the estimation of VO2max.

    Science.gov (United States)

    Naughton, L M; Cooley, D; Kearney, V; Smith, S

    1996-06-01

    The aims of this experiment were twofold. The first was to determine whether there was a significant difference between two types of 20-m shuttle run test used to estimate VO2max, these being the Canadian version (CT) and the European versione (ET). The second aim was to determine which of the two tests best estimated direct VO2 measurement in our laboratory. To accomplish the first aim, 500 schoolchildren aged 12 to 16 years were randomly chosen from schools within Tasmania to undertake the two tests within seven days of each other. On the day of testing the children were assigned to one of the two tests and had no knowledge as to which test was being undertaken. Half of the children underwent the CT test first while the other half undertook the ET test first. Seven days after the first test was completed the appropriate second test was undertaken. The instructions to each child centred around the necessity to complete as many shuttles as possible staying in time with a pre-recorded signal. A relationship between the two sets of shuttle run data indicated that there was a significant correlation between the ET and CT, r = 0.834 (p test revealed that when the estimates of VO2max were compared however, there was a significant difference between the two tests (p VO2max at 34.9 +/- 0.45 ml.kg-1.min-1 whereas the CT estimated VO2max at 43.3 +/- 0.40 ml.kg-1.min-1. When this data was correlated, the co-efficient dropped to r = 0.761 which was still significant (p VO2max test (DM) which was conducted via standard open circuit spirometry using a Quinton Metabolic Cart (QMC). The highest correlation was DM:ET being r = 0.93 whereas DM:CT was r = 0.87, both being significant at p VO2max as 37.6 +/- 0.37 ml.kg-1.min-1 whereas ET underestimated DM and measured VO2max at 34.7 +/- 0.56 ml.kg-1.min-1. The CT (41.9 +/- 0.62 ml.kg-1.min-1) over estimated DM by 11.4% however, the difference here also being significant (p test or the other in the estimation of VO2max as the two

  9. Comparison of intensities and rest periods for VO2max verification testing procedures.

    Science.gov (United States)

    Nolan, P B; Beaven, M L; Dalleck, L

    2014-11-01

    We sought to determine the incidence of 'true' VO2max confirmation with the verification procedure across different protocols. 12 active participants (men n=6, women n=6) performed in random order 4 different maximal graded exercises tests (GXT) and verification bout protocols on 4 separate days. Conditions for the rest period and verification bout intensity were: A - 105% intensity, 20 min rest; B - 105% intensity, 60 min rest; C - 115% intensity, 20 min rest; D - 115% intensity, 60 min rest. VO2max confirmation (difference between peak VO2 GXT and verification trialVO2max confirmation across all exercise test conditions (intensity effect within recovery 20 min (χ(2) (1)=4.800, pVO2max confirmation with different rest periods. We recommend the use of 105% of the maximal GXT workload and 20 min rest periods when using verification trials to confirm VO2max in normally active populations. © Georg Thieme Verlag KG Stuttgart · New York.

  10. Verification Testing to Confirm VO2max in Altitude-Residing, Endurance-Trained Runners.

    Science.gov (United States)

    Weatherwax, R M; Richardson, T B; Beltz, N M; Nolan, P B; Dalleck, L

    2016-06-01

    We sought to explore the utility of the verification trial to confirm individual attainment of 'true' VO2max in altitude-residing, endurance-trained runners during treadmill exercise. 24 elite endurance-trained men and women runners (age=21.5±3.3 yr, ht=174.8±9.3 cm, body mass=60.5±6.7 kg, PR 800 m 127.5±13.1 s) completed a graded exercise test (GXT) trial (VO2max=60.0±5.8 mL·kg(-1)·min(-1)), and returned 20 min after incremental exercise to complete a verification trial (VO2max=59.6±5.7 mL·kg(-1)·min(-1)) of constant load, supramaximal exercise. The incidence of 'true' VO2max confirmation using the verification trial was 24/24 (100%) with all participants revealing differences in VO2max≤3% (the technical error of our equipment) between the GXT and verification trials. These findings support use of the verification trial to confirm VO2max attainment in altitude-residing, endurance-trained runners. © Georg Thieme Verlag KG Stuttgart · New York.

  11. Reproducibility of maximum aerobic power (VO2max) among soccer players using a modified heck protocol.

    Science.gov (United States)

    Santos-Silva, Paulo Roberto; Fonseca, Alfredo José; Castro, Anita Weigand de; Greve, Júlia Maria D'Andréa; Hernandez, Arnaldo José

    2007-08-01

    To determine the degree of reproducibility of maximum oxygen consumption (VO2max) among soccer players, using a modified Heck protocol. 2 evaluations with an interval of 15 days between them were performed on 11 male soccer players. All the players were at a high performance level; they were training for an average of 10 hours per week, totaling 5 times a week. When they were evaluated, they were in the middle of the competitive season, playing 1 match per week. The soccer players were evaluated on an ergometric treadmill with velocity increments of 1.2 km.h-1 every 2 minutes and a fixed inclination of 3% during the test. VO2max was measured directly using a breath-by-breath metabolic gas analyzer. The maximum running speed and VO2max attained in the 2 tests were, respectively: (15.6 +/- 1.1 vs. 15.7 +/- 1.2 km.h-1; [P = .78]) and (54.5 +/- 3.9 vs. 55.2 +/- 4.4 ml.kg-1.min-1; [P = .88]). There was high and significant correlation of VO2max between the 2 tests with a 15-day interval between them [r = 0.97; P testing was insufficient to significantly modify the soccer players' VO2max values.

  12. Non-exercise estimation of VO2max using the International Physical Activity Questionnaire

    Science.gov (United States)

    Schembre, Susan M.; Riebe, Deborah A.

    2011-01-01

    Non-exercise equations developed from self-reported physical activity can estimate maximal oxygen uptake (VO2max) as well as submaximal exercise testing. The International Physical Activity Questionnaire (IPAQ) is the most widely used and validated self-report measure of physical activity. This study aimed to develop and test a VO2max estimation equation derived from the IPAQ-Short Form (IPAQ-S). College-aged males and females (n = 80) completed the IPAQ-S and performed a maximal exercise test. The estimation equation was created with multivariate regression in a gender-balanced subsample of participants, equally representing five levels of fitness (n = 50) and validated in the remaining participants (n = 30). The resulting equation explained 43% of the variance in measured VO2max (SEE = 5.45 ml·kg-1·min-1). Estimated VO2max for 87% of individuals fell within acceptable limits of error observed with submaximal exercise testing (20% error). The IPAQ-S can be used to successfully estimate VO2max as well as submaximal exercise tests. Development of other population-specific estimation equations is warranted. PMID:21927551

  13. Echinacea purpurea supplementation does not enhance VO2max in distance runners.

    Science.gov (United States)

    Baumann, Cory W; Bond, Kelsey L; Rupp, Jeffrey C; Ingalls, Christopher P; Doyle, J Andrew

    2014-05-01

    Oral supplementation of Echinacea purpurea (ECH) has been reported to increase levels of serum erythropoietin and as a result improve endurance performance in untrained subjects. The purpose of this study was to determine if ECH supplementation alters maximal oxygen uptake (VO2max) in trained endurance runners. Using a double-blind design, 16 trained endurance runners (9 ECH and 7 placebo [PLA]) supplemented with either 8,000 mg·d(-1) of ECH or wheat flour (PLA) for 6 weeks. Maximal aerobic treadmill tests and blood samples were measured before and after supplementation to determine VO2max, hematocrit (Hct), and hemoglobin (Hb). VO2max, Hct, and Hb did not differ between the ECH and PLA groups before or after supplementation. Furthermore, supplementation of ECH failed to improve VO2max (67.37 ± 4.62 vs. 67.23 ± 5.82 ml·kg(-1)·min(-1)), Hct (43.57 ± 2.38 vs. 42.85 ± 1.46%), or Hb (14.93 ± 1.27 vs. 15.55 ± 0.80 g·dL(-1)) from baseline measurements. Echinacea purpurea supplementation of 8,000 mg·d(-1) for 6 weeks failed to increase VO2max, Hct, or Hb in trained endurance runners and thus does not seem to influence physiological variables that affect distance running performance.

  14. VO2 Max and Back and Leg Muscle Strength Profile of Universitas Padjadjaran Swimming Team

    Directory of Open Access Journals (Sweden)

    Pitriyani Nurul Pajar

    2016-12-01

    Full Text Available Background: Cardiorespiratory endurance (VO2 max and back and leg muscle strength are a few components required to support the performance of swimming athlete during competition. The objective of this study was to determine the VO2 max and back and leg muscle strength in high category level of Universitas Padjadjaran swimming team period 2014. Methods: A descriptive study was conducted to 19 swimmers of Universitas Padjadjaran in September 2014. The variables of this study were VO2 max and back and leg muscle strength. Then, the data were categorized based on the standard of The National Sports Committee of Indonesia. Results: The data obtained showed that the VO2 max of the majority of subjects was in the very good category (6/19 subjects and the back muscle strength of the majority of subjects was in the very good category (10/19 subjects. In contrast, the leg muscle strength of majority of subjects was in the low category (11/19 subjects. Conclusions: The VO2 max and back muscle strength in high category level of the swimming team fulfilled the standard of The National Sports Committee of Indonesia.

  15. Relationship between running kinematic changes and time limit at vVO2max. DOI: http://dx.doi.org/10.5007/1980-0037.2012v14n4p428

    Directory of Open Access Journals (Sweden)

    Sebastião Iberes Lopes Melo

    2012-07-01

    Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2012v14n4p428Exhaustive running at maximal oxygen uptake velocity (vVO2max can alter running kinematic parameters and increase energy cost along the time. The aims of the present study were to compare characteristics of ankle and knee kinematics during running at vVO2max and to verify the relationship between changes in kinematic variables and time limit (Tlim. Eleven male volunteers, recreational players of team sports, performed an incremental running test until volitional exhaustion to determine vVO2max and a constant velocity test at vVO2max. Subjects were filmed continuously from the left sagittal plane at 210 Hz for further kinematic analysis. The maximal plantar flexion during swing (p<0.01 was the only variable that increased significantly from beginning to end of the run. Increase in ankle angle at contact was the only variable related to Tlim (r=0.64; p=0.035 and explained 34% of the performance in the test. These findings suggest that the individuals under study maintained a stable running style at vVO2max and that increase in plantar flexion explained the performance in this test when it was applied in non-runners.

  16. Development of a branching submaximal treadmill test for predicting VO2max.

    Science.gov (United States)

    Swank, A M; Serapiglia, L; Funk, D; Adams, K J; Durham, M; Berning, J M

    2001-08-01

    This study determined the reliability and validity of a branching treadmill protocol in predicting VO2max. Thirty-seven, apparently healthy individuals (19 women and 18 men); volunteered to participate. On 2 separate testing days, each subject underwent maximal exercise testing using the protocol developed. Stepwise regression analysis indicated that the percentage of age-predicted maximum heart rate (APMHR) achieved at stage 3, speed and grade at stage 3, and APMHR accounted for 89% of the variance in VO2max. The 4 predictor variables were statistically significant (p VO2max for their clients outside the laboratory environment. Furthermore, our results indicate that using the proposed regression model is reliable and has received preliminary construct validity support.

  17. Effect of high-intensity interval training on cardiovascular function, VO2max, and muscular force.

    Science.gov (United States)

    Astorino, Todd A; Allen, Ryan P; Roberson, Daniel W; Jurancich, Matt

    2012-01-01

    The purpose of this study was to examine the effects of short-term high-intensity interval training (HIIT) on cardiovascular function, cardiorespiratory fitness, and muscular force. Active, young (age and body fat = 25.3 ± 4.5 years and 14.3 ± 6.4%) men and women (N = 20) of a similar age, physical activity, and maximal oxygen uptake (VO2max) completed 6 sessions of HIIT consisting of repeated Wingate tests over a 2- to 3-week period. Subjects completed 4 Wingate tests on days 1 and 2, 5 on days 3 and 4, and 6 on days 5 and 6. A control group of 9 men and women (age and body fat = 22.8 ± 2.8 years and 15.2 ± 6.9%) completed all testing but did not perform HIIT. Changes in resting blood pressure (BP) and heart rate (HR), VO2max, body composition, oxygen (O2) pulse, peak, mean, and minimum power output, fatigue index, and voluntary force production of the knee flexors and extensors were examined pretraining and posttraining. Results showed significant (p VO2max, O2 pulse, and Wingate-derived power output with HIIT. The magnitude of improvement in VO2max was related to baseline VO2max (r = -0.44, p = 0.05) and fatigue index (r = 0.50, p 0.05) in resting BP, HR, or force production was revealed. Data show that HIIT significantly enhanced VO2max and O2 pulse and power output in active men and women.

  18. Development of a rowing-specific VO2max field test.

    Science.gov (United States)

    Huntsman, Heather D; DiPietro, Loretta; Drury, Daniel G; Miller, Todd A

    2011-06-01

    The purpose of this study was to develop an aerobic capacity test for rowers using minimal equipment that could be used in the field. Thirty rowers (15 men and 15 women) between the ages of 18 and 26 years were recruited on a volunteer basis from the District of Columbia metro area. The testing protocol consisted of a maximum of 7 2-minute stages on a rowing ergometer, separated by 30-second breaks where lactic acid concentrations were analyzed. Starting intensity for men was 200 W, although women started at 150 W, and each stage increased by 50 W. Expired gasses were collected during the test, and athletes were asked to row until maximal volition so that the directly measured VO2max could be compared to predicted values. Peak heart rates from each completed stage were plotted, and regression equations were calculated to predict VO2max. Separate regression equations were calculated for men and women. The predicted VO2max values were approximately 23 and 25% lower than what was actually achieved for men and women, respectively. Heart rate was a stronger correlate of VO2max in men compared with in women. Among men, we observed a moderate and statistically significant correlation (r = 0.55; p = 0.05), whereas among women, no such agreement was observed (r = -0.05; p > 0.85). The principle finding of this study was that the test was adequate in predicting VO2max in men but was inadequate in its prediction in women. With slight modifications to the testing protocol, stronger correlations and a more accurate prediction of VO2max is expected in men.

  19. Estimated VO2max and its corresponding velocity predict performance of amateur runners

    Directory of Open Access Journals (Sweden)

    Bruno Ribeiro Ramalho Oliveira

    2012-03-01

    Full Text Available In recent years, there has been a substantial increase in the number of runners, with a proportional increase in their involvement in amateur street competition. Identification of the determinants of performance in this population appears necessary for optimization of time devoted to training. The objective of this study was to ascertain the association between estimated maximal oxygen uptake (VO2max, critical velocity (CV and VO2max velocity (VVO2max and athletic performance in the 3.6 km (uphill and 10 and 21.1 km (flatland events. Twelve amateur runners (nine male, mean age 36 ± 5 years underwent five tests: 1 and 5 km race on level ground, 3.6 km race with slope (≈8%, and indirect VO2max measurement. CV was determined from the linear relationship between distance and run time on the first two tests. The subjects then took part in two official 10 km and 21.1 km (half marathon races. VVO2max was calculated from the VO2max through a metabolic equation. VO2max showed the best association with running performance in the 10 and 21.1 km events. For the uphill race, VVO2max showed a better association. Overall, the variable with the highest average association was VO2max (0.91±0.07, followed by VVO2max (0.90±0.04 and VC (0.87±0.06. This study showed strong associations between physiological variables established by low-cost, user-friendly indirect methods and running performance in the 10 and 21.1 km (flatland and 3.6 km (uphill running events.

  20. Markers of inflammation are inversely associated with VO2 max in asymptomatic men.

    Science.gov (United States)

    Kullo, Iftikhar J; Khaleghi, Mahyar; Hensrud, Donald D

    2007-04-01

    We investigated whether markers of inflammation, including a cytokine (IL-6), acute-phase reactants [C-reactive protein (CRP) and fibrinogen], and white blood cell (WBC) count are associated with maximal O(2) consumption (Vo(2 max)) in men without coronary heart disease (CHD). In asymptomatic men (n = 172, 51 +/- 9.3 yr old), Vo(2 max) was measured during a symptom-limited graded treadmill exercise test. Physical activity level was assessed by a standardized questionnaire. IL-6 and CRP were measured by immunoassays, fibrinogen by the Clauss method, and WBC count with a Coulter counter. IL-6 and CRP were logarithmically transformed to reduce skewness. Multivariable regression was used to assess whether markers of inflammation were associated with Vo(2 max) after adjustment for age, body mass index, CHD risk factors, and lifestyle variables (physical activity level, percent body fat, and alcohol intake). Vo(2 max) was 34.5 ml.kg(-1).min(-1) (SD 6.1). Log IL-6 (r = -0.38, P max). In separate multivariable linear regression models that adjusted for age, body mass index, CHD risk factors, and lifestyle variables, log IL-6 [beta-coeff = -1.66 +/- 0.63 (SE), P = 0.010], log CRP [beta-coeff = -0.99 +/- 0.33 (SE), P = 0.003], fibrinogen [beta-coeff = -1.51 +/- 0.44 (SE), P = 0.001], and WBC count [beta-coeff = -0.52 +/- 0.30 (SE), P = 0.088] were each inversely associated with Vo(2 max). In conclusion, higher circulating levels of IL-6, CRP, and fibrinogen are independently associated with lower Vo(2 max) in asymptomatic men.

  1. The reliability of aerobic capacity (VO2max) testing in adolescent girls.

    Science.gov (United States)

    Pivarnik, J M; Dwyer, M C; Lauderdale, M A

    1996-09-01

    Despite the fact that our subjects were naive regarding the test procedures, it appears that aerobic fitness testing using an incremental treadmill protocol is extremely reliable in adolescent girls. In addition, day-to-day variability of VO2max in our subjects averaged less than 5%, which is similar to results obtained with adults (Katch, Sady, & Freedson, 1982). Finally, it was most encouraging to find that a single VO2max test trial resulted in high reliability coefficients. This finding should provide a great deal of confidence to investigators who are performing aerobic fitness tests on large numbers of subjects where multiple testing is neither practical nor cost-effective.

  2. Gas exchange threshold and VO2max testing for athletes: an update.

    Science.gov (United States)

    Pettitt, Robert W; Clark, Ida E; Ebner, Stacy M; Sedgeman, Daniel T; Murray, Steven R

    2013-02-01

    Standardized graded exercise test (GXT) protocols are ineffective for testing endurance athletes. Scientists have called for the abandonment of traditional techniques for corroborating "true" maximum oxygen uptake (VO2max), as measured during a GXT. Instead, a new technique, the verification bout subsequent to the GXT, has emerged for establishing the "true" VO2max. The addition of the verification bout reframes how the GXT should be viewed. In this article, we summarize the methods for developing custom GXT protocols, identifying threshold and interpolating power or outdoor running velocity, and implicating the verification bout.

  3. Study of the relationship between the aerobic capacity (VO2 max) and the rating of perceived exertion based on the measurement of heart beat in the metal industries Esfahan

    Science.gov (United States)

    Habibi, Ehsanollah; Dehghan, Habibollah; Moghiseh, Mohammad; Hasanzadeh, Akbar

    2014-01-01

    Background and Objective: To establish a balance between work (physical exercise) and human beings, the aerobic capacity (VO2 max) could be used as a measure. Additionally, the subjective and physiological assessment could be applied as one of the methods for assessing physical exercise. The most commonly used tools for the assessment of fatigue during physical exercise include the Borg scale Rating of perceived Exertion (RPE) in relation to subjective symptoms and heart rate (HR) in relation to physiological symptoms. The study is aimed to investigate the relationship between the aerobic capacity and the RPE based on the measurement of heat rate (HR) of workers from the Metal Industries of Isfahan. Materials and Methods: The subjects were 200 male workers from metal components manufacturers in Isfahan selected by using random sampling based on statistic method. The subjects were examined by using ergometer in accordance with A strand 6 minutes cycle test protocol. Furthermore, the subjects were asked to rate their status based on the Borg rating scale at the end of each minute. Additionally, their heat rates were monitored and recorded automatically at the end of each minutes. Results: Statistical analysis showed that there was a significant relationship between the RPE and the aerobic capacity (VO2 max) (r = –0.904, P VO2 max (r = 0.991, P VO2 max and HR. Conclusions: The results indicated that there was a strong relationship between the RPE and VO2 max, as well as a greater correlation between HR and VO2 max. Therefore, the HR could be used as a Prediction measure to estimate VO2 max. PMID:25077148

  4. Earbud-Based Sensor for the Assessment of Energy Expenditure, Heart Rate, and VO2max

    Science.gov (United States)

    LeBoeuf, Steven F.; Aumer, Michael E.; Kraus, William E.; Johnson, Johanna L.; Duscha, Brian

    2014-01-01

    Introduction/Purpose The goal of this program was to determine the feasibility of a novel noninvasive, highly miniaturized optomechanical earbud sensor for accurately estimating total energy expenditure (TEE) and maximum oxygen consumption (VO2max). The optomechanical sensor module, small enough to fit inside commercial audio earbuds, was previously developed to provide a seamless way to measure blood flow information during daily life activities. The sensor module was configured to continuously measure physiological information via photoplethysmography (PPG) and physical activity information via accelerometry. This information was digitized and sent to a microprocessor where digital signal processing (DSP) algorithms extract physiological metrics in real-time. These metrics were streamed wirelessly from the earbud to a computer. Methods In this study, 23 subjects of multiple physical habitus were divided into a training group of 14 subjects and a validation group of 9 subjects. Each subject underwent the same exercise measurement protocol consisting of treadmill-based cardiopulmonary exercise (CPX) testing to reach VO2max. Benchmark sensors included a 12-lead electrocardiography (ECG) sensor for measuring heart rate, a calibrated treadmill for measuring distance and speed, and a gas-exchange analysis instrument for measuring TEE and VO2max. The earbud sensor was the device under test (DUT). Benchmark and DUT data collected from the 14-person training dataset study were integrated into a preconceived statistical model for correlating benchmark data with earbud sensor data. Coefficients were optimized, and the optimized model was validated in the 9-person validation dataset. Results It was observed that the earbud sensor estimated TEE and VO2max with mean ± SD percent estimation errors of −0.7 ± 7.4% and −3.2 ± 7.3% respectively. Conclusion The earbud sensor can accurately estimate TEE and VO2max during CPX testing. PMID:24743110

  5. Earbud-based sensor for the assessment of energy expenditure, HR, and VO2max.

    Science.gov (United States)

    Leboeuf, Steven Francis; Aumer, Michael E; Kraus, William E; Johnson, Johanna L; Duscha, Brian

    2014-01-01

    The goal of this program was to determine the feasibility of a novel noninvasive, highly miniaturized optomechanical earbud sensor for accurately estimating total energy expenditure (TEE) and maximum oxygen consumption (VO2max). The optomechanical sensor module, small enough to fit inside commercial audio earbuds, was previously developed to provide a seamless way to measure blood flow information during daily life activities. The sensor module was configured to continuously measure physiological information via photoplethysmography and physical activity information via accelerometry. This information was digitized and sent to a microprocessor where digital signal-processing algorithms extract physiological metrics in real time. These metrics were streamed wirelessly from the earbud to a computer. In this study, 23 subjects of multiple physical habitus were divided into a training group of 14 subjects and a validation group of 9 subjects. Each subject underwent the same exercise measurement protocol consisting of treadmill-based cardiopulmonary exercise testing to reach VO2max. Benchmark sensors included a 12-lead ECG sensor for measuring HR, a calibrated treadmill for measuring distance and speed, and a gas-exchange analysis instrument for measuring TEE and VO2max. The earbud sensor was the device under test. Benchmark and device under test data collected from the 14-person training data set study were integrated into a preconceived statistical model for correlating benchmark data with earbud sensor data. Coefficients were optimized, and the optimized model was validated in the 9-person validation data set. It was observed that the earbud sensor estimated TEE and VO2max with mean ± SD percent estimation errors of -0.7 ± 7.4% and -3.2 ± 7.3%, respectively. The earbud sensor can accurately estimate TEE and VO2max during cardiopulmonary exercise testing.

  6. Influence of simulated microgravity on the VO2 max of nontrained and trained rats

    Science.gov (United States)

    Woodman, C. R.; Monnin, K. A.; Sebastian, L. A.; Tipton, C. M.

    1993-01-01

    Head-down suspension (HDS) of rats has evolved as a useful model for the simulation of a microgravity environment. Previous HDS experiments with rats have shown an impaired capacity to perform aerobic exercise as demonstrated by reductions in maximum oxygen consumption (VO2 max), treadmill run time (RT), and mechanical efficiency (ME) of treadmill running at submaximal conditions. To determine whether endurance training (TR) before HDS would modify exercise performance, male Sprague-Dawley rats were assigned to nontrained (NT) or TR groups for 6 wk and exposed to HDS or cage control (CC) conditions for 29 days. The rats were tested for VO2 max, RT, and ME before treatment and on days 7, 14, 21, and 28. In addition, water and electrolyte excretion was measured on days 1 and 21 of the experimental period. Before HDS, the TR rats had significantly higher measures of VO2 max (15%) and RT (22%) than the NT rats. On day 28, HDS was associated with significant reductions in absolute VO2 max (ml/min) in TR (-30%) and NT (-14%) rats. Relative VO2 max (ml.min-1.kg-1) was significantly reduced in TR (-15%) but not NT rats. Similar reductions in RT occurred in TR (-37%) and NT (-35%) rats by day 28. ME was reduced 22% in both TR and NT rats after 28 days of suspension. HDS elicited diuresis, natriuresis, and kaliuresis in TR rats after 21 days but not after 24 h. In contrast, HDS-NT rats exhibited no diuretic, natriuretic, or kaliuretic responses.(ABSTRACT TRUNCATED AT 250 WORDS).

  7. Bone mass in girls according to their BMI, VO2 max, hours and years of practice.

    Science.gov (United States)

    Ubago-Guisado, Esther; Martinez-Rodriguez, Alejandro; Gallardo, Leonor; Sánchez-Sánchez, Javier

    2016-11-01

    The accumulation of bone mass during puberty is related with bone health in adulthood. This accumulation is influenced by diverse factors such as body mass index (BMI), maximal oxygen uptake (VO2 max), hours of training and years of sport practice. For this reason, the objective of this study is to analyse the influence of these variables on bone mass in young female athletes. The sample is formed of 120 healthy girls with ages between 9 and 13 (11.32 ± 1.6 years old), divided into two groups depending on their BMI, VO2 max, hours of training and years of sport practice. The participants completed a series of tests to evaluate level of sexual development, body composition (fat mass, lean mass and bone mass) and physical condition. The results show higher values of total lean mass, total fat mass and percentage of body fat in the groups with higher BMI in prepubertal girls and pubertal girls (p VO2 max, in the prepubertal group, girls with lower VO2 max had higher values of total fat mass (p VO2 max also showed a higher total fat mass (p < .05). The studied variables account for a 85% and 75.4% of the variance of total bone mineral content and bone mineral density (BMD), respectively. In conclusion, the content and BMD are closely related with muscle mass and sports practice in young females. The amount of fat mass showed no association with bone mass and physical condition has an indirect relationship with bone development.

  8. Why is VO2 max after altitude acclimatization still reduced despite normalization of arterial O2 content?

    DEFF Research Database (Denmark)

    Calbet, J A L; Boushel, Robert Christopher; Radegran, G

    2003-01-01

    Acute hypoxia (AH) reduces maximal O2 consumption (VO2 max), but after acclimatization, and despite increases in both hemoglobin concentration and arterial O2 saturation that can normalize arterial O2 concentration ([O2]), VO2 max remains low. To determine why, seven lowlanders were studied at VO2...

  9. Crossvalidation of two heart rate-based equations for predicting VO2max in white and black men.

    Science.gov (United States)

    Esco, Michael R; Olson, Michele S; Williford, Henry N; Mugu, Emmanuel M; Bloomquist, Barbara E; McHugh, Aindrea N

    2012-07-01

    The purpose of this investigation was to crossvalidate 2 equations that use the ratio of maximal heart rate (HRmax) to resting HR (HRrest) for predicting maximal oxygen consumption (VO2max) in white and black men. One hundred and nine white (n = 51) and black (n = 58) men completed a maximal exercise test on a treadmill to determine VO2max. The HRrest and HRmax were used to predict VO2max via the HRindex and HRratio equations. Validity statistics were done to compare the criterion versus predicted VO2max values across the entire cohort and within each race separately. For the entire group, VO2max was significantly overestimated with the HRindex equation, but the HRratio equation yielded no significant difference compared with the criterion. In addition, there were no significant differences shown between VO2max and either HR-based prediction equation for the white subgroup. However, both equations significantly overestimated VO2max in the black group. Furthermore, large standard error of estimates (ranging from 6.92 to 7.90 ml·kg(-1)·min(-1)), total errors (ranging from 8.30 to 8.62 ml·kg(-1)·min(-1)), and limits of agreement (ranging from upper limits of 16.65 to lower limits of -18.25 ml·kg(-1)·min(-1)) were revealed when comparing the predicted to criterion VO2max for both the groups. Considering the results of this investigation, the HRratio and HRindex methods appear to crossvalidate and prove useful for estimating the mean VO2max in white men as a group but not for an age-matched group of black men. However, because of inflated values for error, caution should be exercised when using these methods to predict individual VO2max.

  10. Monitoring VO2max during fourteen weeks of endurance training using the CardioCoach.

    Science.gov (United States)

    Vehrs, Pat R; Keller, David M; George, James D; Hager, Ronald L; Fellingham, Gilbert W

    2007-02-01

    This study evaluated the validity of the desktop CardioCoach metabolic system to measure VO2max and VEmax. Sixteen subjects (mean age = 19.5 +/- 3.2 years) completed 2 maximal graded exercise tests following the same protocol before and after 7 and 14 weeks of endurance training. Subjects' VO2max and VEmax were measured by either the CardioCoach or the ParvoMedics TrueOne 2400 metabolic measurement system (TrueOne). An alpha level of significance of p test completion and the final treadmill grade of the exercise tests performed by both the CardioCoach and the TrueOne increased over the 3 testing periods, confirming an improvement in cardiorespiratory fitness resulting from the 14 weeks of training. A linear growth curve analysis indicated that there were statistically significant differences between VO2max (ml x kg(-1) x min(-1)) as measured by the TrueOne and the CardioCoach before (44.4 +/- 5.0 and 49.3 +/- 5.4) and after 7 weeks (46.0 +/- 5.2 and 48.2 +/- 5.4) of training but not after 14 weeks of training (47.8 +/- 5.6 and 48.4 +/- 5.2). Significant differences also existed in VEmax (L x min(-1)) as measured by the TrueOne and the CardioCoach before (76.8 +/- 17.7 and 71.9 +/- 13.7), after 7 weeks (81.4 +/- 16.2 and 72.8 +/- 14.1), and after 14 weeks (86.8 +/- 19.4 and 74.2 +/- 13.1) of training. Although significant growth of VO2max (0.24 ml x kg(-1) x min(-1) x wk(-1)) and VEmax (0.71 L x min(-1) x wk(-1)) was measured by the TrueOne over 14 weeks of training, the CardioCoach was unable to detect growth in VO2max (-0.02 ml x kg(-1) x min(-1) x wk(-1)) or VEmax (0.17 L x min(-1) x wk(-1)). This study indicates that the CardioCoach did not accurately measure or monitor changes in VO2max or VEmax resulting from training.

  11. Effect of blood haemoglobin concentration on V(O2,max) and cardiovascular function in lowlanders acclimatised to 5260 m

    DEFF Research Database (Denmark)

    Calbet, J A L; Rådegran, G; Boushel, Robert Christopher

    2002-01-01

    The principal aim of this investigation was to determine the influence of blood haemoglobin concentration ([Hb]) on maximal exercise capacity and maximal O(2) consumption (V(O(2),max)) in healthy subjects acclimatised to high altitude. Secondarily, we examined the effects of [Hb] on the regulation...... of cardiac output (CO), blood pressure and muscular blood flow (LBF) during exercise. Eight Danish lowlanders (three females and five males; 24 +/- 0.6 years, mean +/- S.E.M.) performed submaximal and maximal exercise on a cycle ergometer after 9 weeks at an altitude of 5260 m (Mt Chacaltaya, Bolivia......). This was done first with the high [Hb] resulting from acclimatisation and again 2-4 days later, 1 h after isovolaemic haemodilution with Dextran 70 to near sea level [Hb]. After measurements at maximal exercise while breathing air at each [Hb], subjects were switched to hyperoxia (55 % O(2) in N(2...

  12. Peak treadmill running velocity during the VO2 max test predicts running performance.

    Science.gov (United States)

    Noakes, T D; Myburgh, K H; Schall, R

    1990-01-01

    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 ultra-marathon 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.

  13. Elite cross-country skiers do not reach their running VO2max during roller ski skating.

    Science.gov (United States)

    Losnegard, T; Hallén, J

    2014-08-01

    Cross-country skiers' VO2max is often measured during treadmill running. However, VO2max during treadmill skiing with the diagonal stride technique is higher, whereas it is lower during double poling, another classical style technique. How these values compare to VO2max during ski skating in elite cross country skiers is not known. Therefore, this study compared VO2max during treadmill uphill running and treadmill roller ski skating. Twenty-two males (21±2 years, 182±6 cm, 77±7 kg, VO2max running; 72.4±4.4 mL·kg-1·min-1) elite cross-country skiers and biathlon athletes underwent testing in both running and roller ski skating before (May) and at the end (October) of the preseason training. From May to October VO2max increased during running (3.1±4.5%, P=0.003, Effect size; ES=0.44, small) but not during roller ski skating (1.8±5.6%, P=0.13, ES=0.24, small). In May the subjects' VO2max during running was 1.7±4.7% higher compared to during roller ski skating (P=0.08, ES=0.24, small) while in October this difference was 3.0±5.0 % (PVO2max during roller ski skating than during running and this relationship does not change during the pre-season training period.

  14. Effects of concurrent training on explosive strength and VO(2max) in prepubescent children.

    Science.gov (United States)

    Marta, C; Marinho, D A; Barbosa, T M; Izquierdo, M; Marques, M C

    2013-10-01

    The purpose of this study was to compare the effects of an 8-weeks training period of resistance training alone (GR), combined resistance and endurance training (GCON) and a control group (GC) on explosive strength and V(O2max) in a large sample of prepubescent boys and girls. 125 healthy children (58 boys, 67 girls), aged 10-11 years old (10.8±0.4 years) were assigned into 2 training groups to train twice a week for 8 weeks: GR (19 boys, 22 girls), GCON (21 boys, 24 girls) and a control group (GC: 18 boys, 21 girls; no training program). A significant but medium-sized increase from pre- to the post-training in the vertical jump (Effect size=0.22, F=34.44, ptraining group (GR and GCON) and sex factors did not significantly influence the evolution of strength variables from pre- to the post-training. The V(O2max) increased significantly only in GCON. Concurrent training is equally effective on training-induced explosive strength, and more efficient than resistance training only for V(O2max), in prepubescent boys and girls. This should be taken into consideration in order to optimize strength training school-based programs. © Georg Thieme Verlag KG Stuttgart · New York.

  15. EVALUATION AND COMPARISON OF VO2MAX ASSESSMENT MODELS IN HIGH SCHOOL STUDENTS

    Directory of Open Access Journals (Sweden)

    Lotfali Bolboli

    2013-02-01

    Full Text Available The purpose of this study was to evaluation and comparison of VO2max assessment models in students. Thirty students from high schools of Ardabil city were selected randomly and served as subjects in this study (age: 15.73±0.69 year, height: 169.46±8.1 cm, weight: 61.70±9.32 kg. Subjects were divided into two groups. In one group Rockport test was used to estimate their VO2 max and in other group Balk test was used for the same purpose. Also, the VO2max of both groups were examined by a standard treadmill test and the results were compared with the results of field tests. The one way of ANOVA and Tukey's post-hoc tests were used for data analysis (p>0/05. The results showed that there were significant differences between the results of the field tests and standard treadmill test (Bruce: 40.93±5.83 vs. Rockport: 58.71±2.73 and Balke: 52.09± 6.18. As a result of these findings it was concluded that the regression equations used in this study used is not suitable for 15-17 (yr boys and does not estimate their aerobic power correctly.

  16. Determinants of VO2 max decline with aging: an integrated perspective.

    Science.gov (United States)

    Betik, Andrew C; Hepple, Russell T

    2008-02-01

    Aging is associated with a progressive decline in the capacity for physical activity. Central to this decline is a reduction in the maximal rate of oxygen utilization, or VO2 max. This critical perspective examines the roles played by the factors that determine the rate of muscle oxygen delivery versus those that determine the utilization of oxygen by muscle as a means of probing the reasons for VO2 max decline with aging. Reductions in muscle oxygen delivery, principally due to reduced cardiac output and perhaps also a maldistribution of cardiac output, appear to play the dominant role up until late middle age. On the other hand, there is a decline in skeletal muscle oxidative capacity with aging, due in part to mitochondrial dysfunction, which appears to play a particularly important role in extreme old age (senescence) where skeletal muscle VO2 max is observed to decline by approximately 50% even under conditions of similar oxygen delivery as young adult muscle. It is noteworthy that at least the structural aspects of the capillary bed do not appear to be reduced in a manner that would compromise the capacity for muscle oxygen diffusion even in senescence.

  17. Crossvalidation of two 20-m shuttle-run tests for predicting VO2max in female collegiate soccer players.

    Science.gov (United States)

    Green, Michael S; Esco, Michael R; Martin, Tyler D; Pritchett, Robert C; McHugh, Aindrea N; Williford, Henry N

    2013-06-01

    The aim of this study was twofold: (a) to compare the maximal attained speed (MAS) from the 20-m shuttle (MST) and 20-m square-shuttle (SST) tests and (b) to crossvalidate 2 equations for predicting maximal oxygen consumption (VO2max) that were previously developed from MST and SST in a group of female collegiate soccer players. Thirty-nine subjects (age: 20.1 ± 1.5 years) participated in the study. A maximal graded exercise treadmill test was used to measure VO2max. In addition, VO2max was predicted from the MAS obtained during MST ((pred)VO2maxMST) and SST ((pred)VO2maxSST) using previously developed equations. Measured VO2max for the group was 44.2 ± 3.3 ml·kg(-1)·min(-1). The MAS was 12.5 ± 0.6 km·h(-1) for MST and 13.3 ± 0.8 km·h(-1) for SST (p < 0.05). The prediction methods yielded a (pred)VO2maxMST of 49.6 ± 3.9 ml·kg(-1)·min(-1) and predVO2maxSST of 41.8 ± 3.1 ml·kg(-1)·min(-1), which were significantly different from measured VO2max (p < 0.05). The validity statistics revealed the following constant error (CE), correlation coefficient (r), standard error of estimate (SEE), and total error (TE) for (pred)VO2maxMST and (pred)VO2maxSST: CE = 5.35 ± 3.83, r = 0.45 (p < 0.05), SEE = 2.97 ml·kg(-1)·min(-1), TE = 6.39 ml·kg(-1)·min(-1); and CE = -2.43 ± 2.49, r = 0.69 (p < 0.05), SEE = 2.39 ml·kg(-1)·min(-1), TE = 3.43 ml·kg(-1)·min(-1), respectively. Residual plots indicated no proportional bias for either prediction model. The results of this study suggest that female collegiate soccer players had a higher MAS from SST compared with that from MST. In addition, SST appeared to be a more accurate predictor of VO2max than MST in the group of athletes.

  18. A cycle ergometer test of maximal aerobic power.

    Science.gov (United States)

    Myles, W S; Toft, R J

    1982-01-01

    An indirect test of maximal aerobic power (IMAP) was evaluated in 31 healthy male subjects by comparing it with a direct treadmill measurement of maximal aerobic power (VO2 max), with the prediction of VO2 max from heart rate during submaximal exercise on a cycle ergometer using Astrand's nomogram, with the British Army's Basic Fitness Test (BFT, a 2.4 km run performed in boots and trousers), and with a test of maximum anaerobic power. For the IMAP test, subjects pedalled on a cycle ergometer at 75 revs X min-1. The workload was 37.5 watts for the first minute, and was increased by 37.5 watts every minute until the subject could not continue. Time to exhaustion was recorded. Predicted VO2 max and times for BFT and IMAP correlated significantly (p less than 0.001) with the direct VO2 max: r = 0.70, r = 0.67 and r = 0.79 respectively. The correlation between direct VO2 max and the maximum anaerobic power test was significant (p less than 0.05) but lower, r = 0.44. Although lactate levels after direct VO2 max determination were significantly higher than those after the IMAP test, maximum heart rates were not significantly different. Submaximal VO2 values measured during the IMAP test yielded a regression equation relating VO2 and pedalling time. When individual values for direct and predicted VO2 max and times for BFT and IMAP were compared with equivalent standards, the percentages of subjects able to exceed the standard were 100, 65, 87, and 87 respectively. These data demonstrate that the IMAP test provides a valid estimate of VO2 max and indicate that it may be a practical test for establishing that an individual meets a minimum standard.

  19. Estimation of VO2max from the ratio between HRmax and HRrest--the Heart Rate Ratio Method.

    Science.gov (United States)

    Uth, Niels; Sørensen, Henrik; Overgaard, Kristian; Pedersen, Preben K

    2004-01-01

    The effects of training and/or ageing upon maximal oxygen uptake ( VO(2max)) and heart rate values at rest (HR(rest)) and maximal exercise (HR(max)), respectively, suggest a relationship between VO(2max) and the HR(max)-to-HR(rest) ratio which may be of use for indirect testing of VO(2max). Fick principle calculations supplemented by literature data on maximum-to-rest ratios for stroke volume and the arterio-venous O(2) difference suggest that the conversion factor between mass-specific VO(2max) (ml.min(-1).kg(-1)) and HR(max).HR(rest)(-1) is approximately 15. In the study we experimentally examined this relationship and evaluated its potential for prediction of VO(2max). VO(2max) was measured in 46 well-trained men (age 21-51 years) during a treadmill protocol. A subgroup ( n=10) demonstrated that the proportionality factor between HR(max).HR(rest)(-1) and mass-specific VO(2max) was 15.3 (0.7) ml.min(-1).kg(-1). Using this value, VO(2max) in the remaining 36 individuals could be estimated with an SEE of 0.21 l.min(-1) or 2.7 ml.min(-1).kg(-1) (approximately 4.5%). This compares favourably with other common indirect tests. When replacing measured HR(max) with an age-predicted one, SEE was 0.37 l.min(-1) and 4.7 ml.min(-1).kg(-1) (approximately 7.8%), which is still comparable with other indirect tests. We conclude that the HR(max)-to-HR(rest) ratio may provide a tool for estimation of VO(2max) in well-trained men. The applicability of the test principle in relation to other groups will have to await direct validation. VO(2max) can be estimated indirectly from the measured HR(max)-to-HR(rest) ratio with an accuracy that compares favourably with that of other common indirect tests. The results also suggest that the test may be of use for VO(2max) estimation based on resting measurements alone.

  20. VO2max estimation from a submaximal 1-mile track jog for fit college-age individuals.

    Science.gov (United States)

    George, J D; Vehrs, P R; Allsen, P E; Fellingham, G W; Fisher, A G

    1993-03-01

    The primary purpose of this study was to develop a submaximal field test for the estimation of maximal oxygen uptake (VO2max) using a 1-mile track jog. A second purpose was to determine the accuracy of the 1.5-mile run in estimating VO2max for both male and female subjects. VO2max was measured in 149 relatively fit college students (males = 88, females = 61) 18-29 yr using a treadmill protocol (mean +/- SD; VO2max = 47.7 +/- 6.3 ml.kg-1 x min-1). Multiple regression analysis (N = 54) to estimate VO2max from the submaximal, steady-state 1-mile track jog yielded the following validation (V) model (r(adi) = 0.87, SEE = 3.0 ml.kg-1 x min-1): VO2max = 100.5 + 8.344* GENDER (0 = female; 1 = male) - 0.1636* BODY MASS (kg) - 1.438* JOG TIME (min.mile-1) - 0.1928* HEART RATE (bpm). To help ensure that a submaximal level of exertion was realized for the 1-mile track jog, elapsed jog time was restricted to > or = 8.0 min for males and > or = 9.0 min for females and exercise HR to < or = 180 bpm. Cross-validation (CV) of the 1-mile track jog comparing observed and estimated VO2max (N = 52) resulted in radj = 0.84, SEE = 3.1 ml.kg-1 x min-1. Multiple regression analysis (N = 50) to estimate VO2max from the 1.5-mile run (V:N = 49, radj = 0.90, SEE = 2.8 ml.kg-1 x min-1; CV: N = 47, radj = 0.82, SEE = 3.9 ml.kg-1 x min-1), used elapsed run time, body mass, and gender as independent variables.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Antepartum cardiorespiratory fitness (CRF) quantification by estimation of maximal oxygen consumption (Vo2 max) in pregnant South Indian women.

    Science.gov (United States)

    Chakaravertty, Biswajit; Parkavi, K; Coumary, Sendhil A; Felix, A J W

    2012-04-01

    The aim of the study was to calculate the maximal oxygen consumption (Vo2max) for pregnant women of varying trimesters and to quantify the cardiorespiratory fitness (CRF)with the objective of being able to determine the exercise dose for antenatal women which can be prescribed to achieve optimal exercise benefits during various trimesters. A study group comprising 64 pregnant women with uncomplicated singleton pregnancy and control group with 77 non-pregnant women were subjected to Cooper's 12 minutes walk test. From the distance covered in 12 minutes, Vo2max was calculated. The Vo2max values were statistically analysed between the non-pregnant and pregnant and also its variability among the trimesters. Percentile tables of Vo2max were drawn and multiple comparisons were applied. Results show that the Vo2max values among non-pregnant and first trimester ranges between 18 and 22 ml/kg/minute. Trimesters II and III had a range of Vo2max values between 16-20 and 14-18 ml/kg/minute respectively. The CRF of pregnant women significantly reduced to 6%, 9% and 18% in each trimester respectively when compared with the reference table framed out of non-pregnant Vo2max values. Among the study group the reduction in Vo2max values had no statistical significance between first 2 trimesters but trimester III significantly differs from other trimesters. The exercise prescription cannot be the same for pregnant and non-pregnant women. Even among the pregnant women, III trimester needs separate exercise prescription from the other two trimesters as CRF is markedly compromised towards term.

  2. Initial Weekly HRV Response is Related to the Prospective Change in VO2max in Female Soccer Players.

    Science.gov (United States)

    Esco, M R; Flatt, A A; Nakamura, F Y

    2016-06-01

    The aim of this study was to determine whether the early response in weekly measures of HRV, when derived from a smartphone application, were related to the eventual change in VO2max following an off-season training program in female soccer athletes. 9 female collegiate soccer players participated in an 11-week off-season conditioning program. In the week immediately before and after the training program, each participant performed a test on a treadmill to determine maximal oxygen consumption (VO2max). Daily measures of the log-transformed root mean square of successive R-R intervals (lnRMSSD) were performed by the participants throughout week 1 and week 3 of the conditioning program. The mean and coefficient of variation (CV) lnRMSSD values of week 1 showed small (r=- 0.13, p=0.74) and moderate (r=0.57, p=0.11), respectively, non-significant correlations to the change in VO2max at the end of the conditioning program (∆VO2max). Significant and near-perfect correlation was found between the change in the weekly mean lnRMSSD values from weeks 1 and 3 (∆lnRMSSDM) and ∆VO2max (r=0.90, p=0.002). The current results have identified that the initial change in weekly mean lnRMSSD from weeks 1 to 3 of a conditioning protocol was strongly associated with the eventual adaptation of VO2max.

  3. Limitations to vasodilatory capacity and .VO2 max in trained human skeletal muscle.

    Science.gov (United States)

    Barden, Jeremy; Lawrenson, Lesley; Poole, Jennifer G; Kim, Jeannie; Wray, D Walter; Bailey, Damian M; Richardson, Russell S

    2007-05-01

    To further explore the limitations to maximal O(2) consumption (.VO(2 max)) in exercise-trained skeletal muscle, six cyclists performed graded knee-extensor exercise to maximum work rate (WR(max)) in hypoxia (12% O(2)), hyperoxia (100% O(2)), and hyperoxia + femoral arterial infusion of adenosine (ADO) at 80% WR(max). Arterial and venous blood sampling and thermodilution blood flow measurements allowed the determination of muscle O(2) delivery and O(2) consumption. At WR(max), O(2) delivery rose progressively from hypoxia (1.0 +/- 0.04 l/min) to hyperoxia (1.20 +/- 0.09 l/min) and hyperoxia + ADO (1.33 +/- 0.05 l/min). Leg .VO(2 max) varied with O(2) availability (0.81 +/- 0.05 and 0.97 +/- 0.07 l/min in hypoxia and hyperoxia, respectively) but did not improve with ADO-mediated vasodilation (0.80 +/- 0.09 l/min in hyperoxia + ADO). Although a vasodilatory reserve in the maximally working quadriceps muscle group may have been evidenced by increased leg vascular conductance after ADO infusion beyond that observed in hyperoxia (increased blood flow but no change in blood pressure), we recognize the possibility that the ADO infusion may have provoked vasodilation in nonexercising tissue of this limb. Together, these findings imply that maximally exercising skeletal muscle may maintain some vasodilatory capacity, but the lack of improvement in leg .VO(2 max) with significantly increased O(2) delivery (hyperoxia + ADO), with a degree of uncertainty as to the site of this dilation, suggests an ADO-induced mismatch between O(2) consumption and blood flow in the exercising limb.

  4. Effect of hindlimb suspension on VO2 max and regional blood flow responses to exercise.

    Science.gov (United States)

    Overton, J M; Woodman, C R; Tipton, C M

    1989-02-01

    Male rodents were studied before and after undergoing one of three treatment conditions for 9 days: 1) cage control (n = 15, CON), 2) horizontal suspension (n = 15, HOZ), and 3) head-down suspension (n = 18, HDT). Testing included measurements of maximal O2 uptake (VO2 max) and select cardiovascular responses to graded treadmill exercise. VO2 max expressed on an absolute basis (ml/min) was significantly decreased after HOZ (-14.1 +/- 2.5%) and HDT (-14.3 +/- 2.0%), while being essentially unchanged in CON (-1.0 +/- 3.3%). Significant reductions in body weight were observed after both HOZ (-10.1 +/- 4.2 g) and HDT (-22.5 +/- 3.3 g), whereas CON animals exhibited a significant increase in weight (10.4 +/- 3.8 g). As a result, when VO2 max was normalized for body weight, all groups exhibited similar significant reductions of 6-7%. Although no differences in heart rate and blood pressure response to graded exercise were observed, the HDT group exhibited greater increases in mesenteric resistance at the same absolute exercise intensity. Furthermore, both suspended groups had higher iliac resistance values during exercise at similar relative exercise conditions, suggesting that muscle blood flow during treadmill running may have been reduced after suspension. In general, the decrements associated with the HOZ and HDT conditions were similar. It was concluded that reduction in exercise capacity and altered cardiovascular responses to exercise observed after 6-9 days of suspension were attributable to a combination of hypokinesia, lack of hindlimb weight bearing, or restraint, rather than to hydrostatic influences associated with HDT.

  5. Applicability of an Indirect VO2max Test: Its Association with the 400 Meters Freestyle Performance

    Directory of Open Access Journals (Sweden)

    Adalberto Veronese da Costa

    Full Text Available Abstract The aim of this study was to evaluate the VO2max using a previously validated indirect test for non-expert adult swimmers and to verify its connection with the 400 meters freestyle test. A total of 17 non-expert male swimmers (21.5 ± 3.12 years were evaluated. Body composition measurements included body weight (74 ± 9.41 kg, height (172.9 ± 5.21 cm and body fat percentage (15.2 ± 4.15 %. Two tests were conducted on different days; the 400 meters freestyle (400 MF and the Progressive Swim Test (PSwT, respectively. The participant's heart rate frequency before and after the test (BHR and AHR was analyzed, as well as the subjective perception of effort (RPE, the number of laps covered (NLP, and the time of test execution measured in minutes. Significant differences were identified in all variables (p - 0.60 was found between AHR and execution time (r > - 0.70, as well as between the VO2max estimated by the PSwT and the 400 MF performance test (r > - 0.70. The Bland-Altman Plot showed that the values discovered were within the established concordance limits of 95% (±1.96 SD. A negative correlation between a swimming test and a test that estimates the VO2max occurred, and the PSwT showed results of greater approximation of the aerobic power of non-expert swimmers. In conclusion, the PSwT is applicable for non-expert adult swimmers.

  6. Individual versus Standardized Running Protocols in the Determination of VO2max.

    Science.gov (United States)

    Sperlich, Paula F; Holmberg, Hans-Christer; Reed, Jennifer L; Zinner, Christoph; Mester, Joachim; Sperlich, Billy

    2015-06-01

    The purpose of this study was to determine whether an individually designed incremental exercise protocol results in greater rates of oxygen uptake (VO2max) than standardized testing. Fourteen well-trained, male runners performed five incremental protocols in randomized order to measure their VO2max: i) an incremental test (INCS+I) with pre-defined increases in speed (2 min at 8.64 km·h(-1), then a rise of 1.44 km·h(-1) every 30 s up to 14.4 km·h(-1)) and thereafter inclination (0.5° every 30 s); ii) an incremental test (INCI) at constant speed (14.4 km·h(-1)) and increasing inclination (2° every 2 min from the initial 0°); iii) an incremental test (INCS) at constant inclination (0°) and increasing speed (0.5 km·h(-1) every 30 s from the initial 12.0 km·h(-1)); iv) a graded exercise protocol (GXP) at a 1° incline with increasing speed (initially 8.64 km·h(-1) + 1.44 km·h(-1) every 5 min); v) an individual exercise protocol (INDXP) in which the runner chose the inclination and speed. VO2max was lowest (-4.2%) during the GXP (p = 0.01; d = 0.06-0.61) compared to all other tests. The highest rating of perceived exertion, heart rate, ventilation and end-exercise blood lactate concentration were similar between the different protocols (p VO2max attained by employing an individual treadmill protocol does not differ from the values derived from various standardized incremental protocols. Key pointsThe mean maximum oxygen uptake during the GXP was lower than for all other tests.Differences in the maximum rate of oxygen uptake between the various protocols exhibited considerable inter-individual variation.From the current findings, it can be concluded that well trained athletes are able to perform an individually designed treadmill running protocol.

  7. The effects of uphill vs. level-grade high-intensity interval training on VO2max, Vmax, V(LT), and Tmax in well-trained distance runners.

    Science.gov (United States)

    Ferley, Derek D; Osborn, Roy W; Vukovich, Matthew D

    2013-06-01

    Uphill running represents a frequently used and often prescribed training tactic in the development of competitive distance runners but remains largely uninvestigated and unsubstantiated as a training modality. The purpose of this investigation included documenting the effects of uphill interval training compared with level-grade interval training on maximal oxygen consumption (VO2max), the running speed associated with VO2max (Vmax), the running speed associated with lactate threshold (V(LT)), and the duration for which Vmax can be sustained (Tmax) in well-trained distance runners. Thirty-two well-trained distance runners (age, 27.4 ± 3.8 years; body mass, 64.8 ± 8.9 kg; height, 173.6 ± 6.4 cm; and VO2max, 60.9 ± 8.5 ml·min(-1)·kg(-1)) received assignment to an uphill interval training group (G(Hill) = 12), level-grade interval training group (G(Flat) = 12), or control group (G(Con) = 8). G(Hill) and G(Flat) completed 12 interval and 12 continuous running sessions over 6 weeks, whereas G(Con) maintained their normal training routine. Pre- and posttest measures of VO2max, Vmax, V(LT), and Tmax were used to assess performance. A 3 × 2 repeated measures analysis of variance was performed for each dependent variable and revealed a significant difference in Tmax in both G(Hill) and G(Flat) (p interval training can induce significant improvements in a run-to-exhaustion test in well-trained runners at the speed associated with VO2max but that traditional level-grade training produces greater gains.

  8. VO2max Measured with a Self-selected Work Rate Protocol on an Automated Treadmill.

    Science.gov (United States)

    Scheadler, Cory M; Devor, Steven T

    2015-10-01

    The use of graded maximal exercise tests for measuring maximal oxygen consumption (VO2max) is common practice in both cardiopulmonary rehabilitation settings and in sports medicine research. Recent alterations of common testing protocols to allow for self-selected work rates (SPV) have elicited V˙O2max values similar to or higher than more traditional style protocols (TP). Research is lacking in the delivery of the SPV protocol using a treadmill modality. The purpose of the study was to examine the validity of an SPV using an automated treadmill for measuring cardiorespiratory fitness. Thirteen experienced endurance runners completed three maximal exercise tests on a treadmill. Oxygen consumption was measured using a computerized system and averaged more than 30-s time periods. SPV was completed using an automated treadmill that consisted of a sonar range finder, microcontroller, and customized computer software. Subject deviations from the middle of the treadmill belt resulted in rapid, graded increases or decreases in speed. TP was completed on the same treadmill without the use of the automated software. A verification phase protocol (VP) was used to verify if VO2 was maximal. Peak work rate achieved during SPV was significantly greater than that achieved during TP by 1.2 METs; P VO2max than TP despite higher work rates.

  9. Exercise tolerance during VO2max testing is a multifactorial psychobiological phenomenon.

    Science.gov (United States)

    Midgley, Adrian W; Earle, Keith; McNaughton, Lars R; Siegler, Jason C; Clough, Peter; Earle, Fiona

    2017-08-21

    Fifty-nine men completed a VO2max test and a questionnaire to establish reasons for test termination, perceived exercise reserve (difference between actual test duration and the duration the individual perceived could have been achieved if continued until physical limitation), and perception of verbal encouragement. Participants gave between 1 and 11 factors as reasons for test termination, including leg fatigue, various perceptions of physical discomfort, safety concerns, and achievement of spontaneously set goals. The two most common main reasons were leg fatigue and breathing discomfort, which were predicted by pre-to-post test changes in pulmonary function (p = 0.038) and explosive leg strength (p = 0.042; R(2) = 0.40). Median (interquartile range) perceived exercise reserve, was 45 (50) s. Two-thirds of participants viewed verbal encouragement positively, whereas one-third had a neutral or negative perception. This study highlights the complexity of exercise tolerance during VO2max testing and more research should explore these novel findings.

  10. Erythropoietin elevates VO2,max but not voluntary wheel running in mice.

    Science.gov (United States)

    Kolb, E M; Kelly, S A; Middleton, K M; Sermsakdi, L S; Chappell, M A; Garland, T

    2010-02-01

    Voluntary activity is a complex trait, comprising both behavioral (motivation, reward) and anatomical/physiological (ability) elements. In the present study, oxygen transport was investigated as a possible limitation to further increases in running by four replicate lines of mice that have been selectively bred for high voluntary wheel running and have reached an apparent selection limit. To increase oxygen transport capacity, erythrocyte density was elevated by the administration of an erythropoietin (EPO) analogue. Mice were given two EPO injections, two days apart, at one of two dose levels (100 or 300 microg kg(-1)). Hemoglobin concentration ([Hb]), maximal aerobic capacity during forced treadmill exercise (VO2,max) and voluntary wheel running were measured. [Hb] did not differ between high runner (HR) and non-selected control (C) lines without EPO treatment. Both doses of EPO significantly (PVO2,max by approximately 5% in both the HR and C lines, with no dosexline type interaction. However, wheel running (revolutions per day) did not increase with EPO treatment in either the HR or C lines, and in fact significantly decreased at the higher dose in both line types. These results suggest that neither [Hb] per se nor VO2,max is limiting voluntary wheel running in the HR lines. Moreover, we hypothesize that the decrease in wheel running at the higher dose of EPO may reflect direct action on the reward pathway of the brain.

  11. Determinants of maximal oxygen uptake (VO2 max) in fire fighter testing.

    Science.gov (United States)

    Vandersmissen, G J M; Verhoogen, R A J R; Van Cauwenbergh, A F M; Godderis, L

    2014-07-01

    The aim of this study was to evaluate current daily practice of aerobic capacity testing in Belgian fire fighters. The impact of personal and test-related parameters on the outcome has been evaluated. Maximal oxygen uptake (VO2 max) results of 605 male fire fighters gathered between 1999 and 2010 were analysed. The maximal cardio respiratory exercise tests were performed at 22 different centres using different types of tests (tread mill or bicycle), different exercise protocols and measuring equipment. Mean VO2 max was 43.3 (SD = 9.8) ml/kg.min. Besides waist circumference and age, the type of test, the degree of performance of the test and the test centre were statistically significant determinants of maximal oxygen uptake. Test-related parameters have to be taken into account when interpreting and comparing maximal oxygen uptake tests of fire fighters. It highlights the need for standardization of aerobic capacity testing in the medical evaluation of fire fighters. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  12. Estimation of Aerobic Capacity (VO2-max and Physical Work Capacity in Laborers

    Directory of Open Access Journals (Sweden)

    Sedeghe Hosseinabadi

    2013-06-01

    Full Text Available Introduction: Measurement of Maximum aerobic capacity (VO2-max is important in physiologically fitting the laborers to the job. This study was conducted to estimate the aerobic capacity and physical work capacity (PWC of workers of galvanize department of Semnan rolling pipe Company and also determine the relative frequency of workers whom their jobs were proportional to their physical work capacity . Methods: 50 male workers of Semnan rolling pipe company were selected randomly to participate in this cross-sectional study. Tuxworth & shahnavaz methods were applied to measure instances VO2-MAX. Independent-Sample t-test and correlation technique were used to analysis the data by SPSS software. Results: Average maximum aerobic capacity of workers was 2.88± .033 liters per minute and the average of physical work capacity was 4.76 ± 0.54 kilocalories per minute. There was a significant relationship between body mass index and aerobic capacity. The result showed that 36 percent of subjects expend more energy than their physical work capacity to perform their duties during the work time. Conclusion: According to the ILO classification, the average physical work capacity of the workers fall into a category of light energy;accordingly, on average, these workers had physical ability to performe less or lighter duties. More than one-third of these workers need to undergo job modification or to change their present job to a job with less energy consumption.

  13. Efeito da intensidade do exercício de corrida intermitente 30s:15s no tempo de manutenção no ou próximo do VO2max Effect of intensity of intermittent running exercise 30s:15s at the time maintenance at or near VO2max

    OpenAIRE

    Rafael Alves de Aguiar; Jardel Schlickmann; Tiago Turnes; Fabrizio Caputo

    2013-01-01

    O presente estudo comparou o tempo mantido acima de 90% (t90VO2max) e de 95% VO2max (t95VO2max) em três diferentes intensidades de exercício. Após a realização de um teste incremental para determinar o VO2max, oito estudantes de educação física ativos (23 ± 3 anos) executaram três sessões de exercícios intermitentes (100, 110 e 120% da velocidade do VO2max (vVO2max)) com razão esforço:recuperação de 30s:15s. O t95VO2max foi significantemente maior em 110%vVO2max (EI110%) (218,1 ± 81,6 s) quan...

  14. Is low VO2max/kg in obese heart failure patients indicative of cardiac dysfunction?

    Science.gov (United States)

    Hothi, S S; Tan, D K; Partridge, G; Tan, L B

    2015-04-01

    Low peak O2 consumption (VO2max/kg) has been widely used as an indirect indicator of poor cardiac fitness, and often guides management of patients with severe heart failure (HF). We hypothesized that it should be as good an indicator of cardiac dysfunction in obese and non-obese HF patients. We compared the cardiopulmonary exercise performance and non-invasive hemodynamics of 152 obese (BMI>34 kg.m(-2)) and 173 non-obese (BMI≤32) male HF patients in NYHA classes II and III, with reference to 101 healthy male controls. Their physical and cardiac functional reserves were measured during treadmill exercise testing with standard respiratory gas analyses and CO2 rebreathing to measure cardiac output non-invasively during peak exercise. Data are given as mean ± SD. Obese HF patients with BMI 40.9 ± 7.5 kg·m(-2) (age 56.1 ± 14.0 years, NYHA 2.5 ± 0.5) exercised to acceptable cardiopulmonary limits (peak RER=1.07 ± 0.12), and achieved a mean VO2max/kg of 18.6 ± 5.2 ml·kg(-1)·min(-1), significantly lower than in non-obese HF counterparts (19.9 ± 5.6 ml·kg(-1)·min(-1), P=0.02, age 55.8 ± 10.6 years, BMI 26.6 ± 3.1, NYHA 2.4 ± 0.5, peak RER=1.07 ± 0.09), with both lower than controls (38.5 ± 9.7 ml·kg(-1)·min(-1), PVO2max was higher in obese (2.31 ± 0.69 ml·min(-1)) than non-obese HF patients (1.61 ± 0.49 ml·min(-1), PVO2max/kg is not a generally reliable indicator of cardiac fitness in all patients. Instead, we found that despite having lower VO2max/kg, obese HF patients had stronger hearts capable of generating greater cardiac power than non-obese HF patients of equivalent clinical HF status. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. Convergent Validity of the One-Mile Run and PACER VO2MAX Prediction Models in Middle School Students

    Directory of Open Access Journals (Sweden)

    Ryan D. Burns

    2014-02-01

    Full Text Available FITNESSGRAM uses an equating method to convert Progressive Aerobic Cardiovascular Endurance Run (PACER laps to One-mile run/walk (1MRW times to estimate aerobic fitness (VO2MAX in children. However, other prediction models can more directly estimate VO2MAX from PACER performance. The purpose of this study was to examine the convergent validity and relative accuracy between 1MRW and various PACER models for predicting VO2MAX in middle school students. Aerobic fitness was assessed on 134 students utilizing the 1MRW and PACER on separate testing days. Pearson correlations, Bland–Altman plots, kappa statistics, proportion of agreement, and prediction error were used to assess associations and agreement among models. Correlation coefficients were strong (r ≥ .80, p .40 and agreement > .90. The results support that PACER models contain convergent validity and strong relative accuracy with the 1MRW model.

  16. [Expired gas analysis--focused on VO2 max and anaerobic threshold].

    Science.gov (United States)

    Omiya, K

    1996-07-01

    Recently, expired gas analysis(EGA) during exercise testing is broadly performed. It has been recognized that anaerobic threshold(AT) and maximal oxygen uptake(VO2 max) may be useful in identifying one's exercise tolerance. AT especially has a good correlation with endurance capacity. In the field of sports medicine, the purposes of EGA are: 1) evaluation of endurance exercise capacity. 2) decision of intensity and frequency for exercise training, and 3) prevention of overtraining syndrome. In the clinical fields, EGA is frequently performed with cardiovascular patients, for example, myocardial infarction(MI), and congestive heart failure(CHF). The purposes are: 1) decision of intensity for exercise therapy with the patients of old MI. 2) evaluation of exercise capacity with the patients' of CHF. 3) index of exercise therapy for hypertension, hyperlipidemia, and diabetes, and 4) evaluation of drug effects including vasodilators and cardiotonics.

  17. Prediction of VO2max from a new field test based on portable indirect calorimetry.

    Science.gov (United States)

    Flouris, Andreas D; Metsios, Giorgos S; Famisis, Konstantinos; Geladas, Nikos; Koutedakis, Yiannis

    2010-01-01

    We assessed the validity and reliability of the new 15m square shuttle run test (SST) for predicting laboratory treadmill test (TT) maximal oxygen uptake (VO(2 max)) compared to the 20 m multistage shuttle run test (MST) in 45 adult males. Thirty participants performed a TT and a SST once to develop a VO( 2max) prediction model. The remaining 15 participants performed the TT and MST once and the SST twice for cross-validation purposes. Throughout testing V O(2max) was determined via portable indirect calorimetry while blood lactate concentration was assessed at the fifth recovery minute. Comparisons of TT V O(2 max) (51.3+/-3.1 ml kg(-1)min(-1)) with SST measured (51.2+/-3.2 ml kg(-1)min(-1)) and predicted (50.9+/-3.3 ml kg(-1)min(-1)) V O(2 max) showed no differences while TT blood lactate was higher compared to SST (10.3+/-1.7 mmol vs. 9.7+/-1.7 mmol, respectively). In contrast, MST measured (53.4+/-3.5 ml kg(-1)min(-1)) and predicted (57.0+/-4.5 ml kg(-1)min(-1)) V O(2 max) and blood lactate (11.2+/-2.0 mmol) were significantly higher compared to TT. No test-retest differences were detected for SST measured and predicted V O(2 max) and blood lactate. It is concluded that the SST is a highly valid and reliable predictive test for V O(2 max). Copyright (c) 2009 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  18. Ratio of total carbon dioxide produced to oxygen consumed is predictive of VO2 max during graded exercise testing

    Directory of Open Access Journals (Sweden)

    DAVID BELLAR

    2016-10-01

    Full Text Available The purpose of the present investigation was to examine the ratio between total cO2 expiration and O2 consumption to vO2max. Twenty-six male (vO2 max: 55.4± 8.3 ml O2/kg*min and thirty- five female (vO2 max: 44.1± 8.1 ml O2/kg*min recreationally active adults volunteered. The participants underwent a custom ramped treadmill protocol (gXT with expired gases monitored. Third order polynomial regression was undertaken for the vO2 and vcO2 by time (r>0.950. regression equations were integrated from 60seconds after the start of the test (to negate any initial hyperventilation until vO2 max. This area under the curve calculation was equal to the total accumulated expired cO2 and consumed O2. The ratio of total cO2 to O2 was calculated (auc ratio. Data analysis was undertaken using multiple linear regression analysis. The model included gender, rer at vO2 max and auc ratio as predictors and relative vO2 max as the outcome. The model was significant with predictor variable gender (b =0.582, p<0.001 and auc ratio (b=-0.298, p=0.019 significant in the model. Based upon these results it would appear that individuals who are more fit relying more heavily on oxidative pathways throughout the course of a GXT.

  19. Interval training at 95% and 100% of the velocity at VO2 max: effects on aerobic physiological indexes and running performance.

    Science.gov (United States)

    Denadai, Benedito S; Ortiz, Marcelo J; Greco, Camila C; de Mello, Marco T

    2006-12-01

    The objective of this study was to analyze the effect of two different high-intensity interval training (HIT) programs on selected aerobic physiological indices and 1500 and 5000 m running performance in well-trained runners. The following tests were completed (n=17): (i) incremental treadmill test to determine maximal oxygen uptake (VO2 max), running velocity associated with VO2 max (vVO2 max), and the velocity corresponding to 3.5 mmol/L of blood lactate concentration (vOBLA); (ii) submaximal constant-intensity test to determine running economy (RE); and (iii) 1500 and 5000 m time trials on a 400 m track. Runners were then randomized into 95% vVO2 max or 100% vVO2 max groups, and undertook a 4 week training program consisting of 2 HIT sessions (performed at 95% or 100% vVO2 max, respectively) and 4 submaximal run sessions per week. Runners were retested on all parameters at the completion of the training program. The VO2 max values were not different after training for both groups. There was a significant increase in post-training vVO2 max, RE, and 1500 m running performance in the 100% vVO2 max group. The vOBLA and 5000 m running performance were significantly higher after the training period for both groups. We conclude that vOBLA and 5000 m running performance can be significantly improved in well-trained runners using a 4 week training program consisting of 2 HIT sessions (performed at 95% or 100% vVO2 max) and 4 submaximal run sessions per week. However, the improvement in vVO2 max, RE, and 1500 m running performance seems to be dependent on the HIT program at 100% vVO2 max.

  20. The ergogenic effect of recombinant human erythropoietin on VO2max depends on the severity of arterial hypoxemia

    DEFF Research Database (Denmark)

    Robach, Paul; Calbet, Jose A L; Thomsen, Jonas J;

    2008-01-01

    Treatment with recombinant human erythropoietin (rhEpo) induces a rise in blood oxygen-carrying capacity (CaO(2)) that unequivocally enhances maximal oxygen uptake (VO(2)max) during exercise in normoxia, but not when exercise is carried out in severe acute hypoxia. This implies that there should...... redistribution of cardiac output toward the exercising legs, whereas this advantageous effect disappeared during severe hypoxia, leaving augmented CaO(2) alone insufficient for improving peak leg O(2) delivery and VO(2). Finally, that VO(2)max was largely dependent on CaO(2) during moderate hypoxia but became...

  1. Percent utilization of VO2 max at 5-km competition velocity does not determine time performance at 5 km among elite distance runners.

    Science.gov (United States)

    Støa, Eva Maria; Støren, Øyvind; Enoksen, Eystein; Ingjer, Frank

    2010-05-01

    The present study investigated to what extent maximum oxygen uptake (VO2 max) and fractional utilization (%VO2 max) in 5-km competition speed correlate with 5-km performance times among elite long distance runners. Eight elite long distance runners with 5-km performance times of 15.10 minutes ( +/- 32 seconds) were tested for VO2 max during an incremental protocol and for %VO2 max during an 8-minute treadmill test at the velocity representing their 5-km seasonal best performance time. There was no correlation between fractional utilization and 5-km performance. The study showed no significant difference between VO2 max obtained during an incremental VO2 max test and %VO2 max when running for 8 minutes at the runner's individual 5-km competition speed. The 5-km time was related to the runner's VO2 max even in a homogenous high-level performance group. In conclusion, the present study found no relationship between fractional utilization and 5-km performance time. Training aiming to increase %VO2 max may thus be of little or no importance in performance enhancement for competitions lasting up to approximately 20 minutes.

  2. Graded Exercise Testing Protocols for the Determination of VO2max: Historical Perspectives, Progress, and Future Considerations.

    Science.gov (United States)

    Beltz, Nicholas M; Gibson, Ann L; Janot, Jeffrey M; Kravitz, Len; Mermier, Christine M; Dalleck, Lance C

    2016-01-01

    Graded exercise testing (GXT) is the most widely used assessment to examine the dynamic relationship between exercise and integrated physiological systems. The information from GXT can be applied across the spectrum of sport performance, occupational safety screening, research, and clinical diagnostics. The suitability of GXT to determine a valid maximal oxygen consumption (VO2max) has been under investigation for decades. Although a set of recommended criteria exists to verify attainment of VO2max, the methods that originally established these criteria have been scrutinized. Many studies do not apply identical criteria or fail to consider individual variability in physiological responses. As an alternative to using traditional criteria, recent research efforts have been directed toward using a supramaximal verification protocol performed after a GXT to confirm attainment of VO2max. Furthermore, the emergence of self-paced protocols has provided a simple, yet reliable approach to designing and administering GXT. In order to develop a standardized GXT protocol, additional research should further examine the utility of self-paced protocols used in conjunction with verification protocols to elicit and confirm attainment of VO2max.

  3. Impact of Body Composition and Vo2 Max on the Competitive Success in Top-Level Handball Players.

    Science.gov (United States)

    Ilic, Vladimir; Ranisavljev, Igor; Stefanovic, Dorde; Ivanovic, Vuk; Mrdakovic, Vladimir

    2015-09-01

    The purpose of the study was to determine the morphological and functional characteristics of 32 Serbian national U20 handball players (age 20.43 +/- 1.16 y; training experience 8.12 +/- 1.89 y) before European championship in Switzerland (2006) and to determinate their impact on competitive performance and outstanding success achieved. The results show that wing players differ from other players in morphological characteristics. Values for body height, weight, BMI, muscle mass and fat mass were significantly lower compared to the other playing positions. Extremely low values of maximal oxygen uptake (VO2 max) were measured in all players (ranged from 2.68 to 4.66 l x min(-1)). Pivots had the highest VO2 max in absolute values (3.76 l x min(-1)), and wing players in relative terms (40.83 ml x kg(-1) x min(-1)). Handball is characterized by high intensity intermittent play, followed by a number of walking breaks and quick substitutions. This makes possible to retain high playing intensity during whole match, because players can be given rest periods whenever needed. This will result in a high intensity game that does not necessarily require high VO2 max. Competitive success in modern top-level handball might be more reliant on optimal tactical preparation than on the body composition and VO2 max of an individual athlete.

  4. Graded Exercise Testing Protocols for the Determination of VO2max: Historical Perspectives, Progress, and Future Considerations

    Directory of Open Access Journals (Sweden)

    Nicholas M. Beltz

    2016-01-01

    Full Text Available Graded exercise testing (GXT is the most widely used assessment to examine the dynamic relationship between exercise and integrated physiological systems. The information from GXT can be applied across the spectrum of sport performance, occupational safety screening, research, and clinical diagnostics. The suitability of GXT to determine a valid maximal oxygen consumption (VO2max has been under investigation for decades. Although a set of recommended criteria exists to verify attainment of VO2max, the methods that originally established these criteria have been scrutinized. Many studies do not apply identical criteria or fail to consider individual variability in physiological responses. As an alternative to using traditional criteria, recent research efforts have been directed toward using a supramaximal verification protocol performed after a GXT to confirm attainment of VO2max. Furthermore, the emergence of self-paced protocols has provided a simple, yet reliable approach to designing and administering GXT. In order to develop a standardized GXT protocol, additional research should further examine the utility of self-paced protocols used in conjunction with verification protocols to elicit and confirm attainment of VO2max.

  5. Graded Exercise Testing Protocols for the Determination of VO2max: Historical Perspectives, Progress, and Future Considerations

    Science.gov (United States)

    Gibson, Ann L.; Janot, Jeffrey M.; Kravitz, Len; Dalleck, Lance C.

    2016-01-01

    Graded exercise testing (GXT) is the most widely used assessment to examine the dynamic relationship between exercise and integrated physiological systems. The information from GXT can be applied across the spectrum of sport performance, occupational safety screening, research, and clinical diagnostics. The suitability of GXT to determine a valid maximal oxygen consumption (VO2max) has been under investigation for decades. Although a set of recommended criteria exists to verify attainment of VO2max, the methods that originally established these criteria have been scrutinized. Many studies do not apply identical criteria or fail to consider individual variability in physiological responses. As an alternative to using traditional criteria, recent research efforts have been directed toward using a supramaximal verification protocol performed after a GXT to confirm attainment of VO2max. Furthermore, the emergence of self-paced protocols has provided a simple, yet reliable approach to designing and administering GXT. In order to develop a standardized GXT protocol, additional research should further examine the utility of self-paced protocols used in conjunction with verification protocols to elicit and confirm attainment of VO2max. PMID:28116349

  6. Efeito da intensidade do exercício de corrida intermitente 30s:15s no tempo de manutenção no ou próximo do VO2max Effect of intensity of intermittent running exercise 30s:15s at the time maintenance at or near VO2max

    Directory of Open Access Journals (Sweden)

    Rafael Alves de Aguiar

    2013-03-01

    Full Text Available O presente estudo comparou o tempo mantido acima de 90% (t90VO2max e de 95% VO2max (t95VO2max em três diferentes intensidades de exercício. Após a realização de um teste incremental para determinar o VO2max, oito estudantes de educação física ativos (23 ± 3 anos executaram três sessões de exercícios intermitentes (100, 110 e 120% da velocidade do VO2max (vVO2max com razão esforço:recuperação de 30s:15s. O t95VO2max foi significantemente maior em 110%vVO2max (EI110% (218,1 ± 81,6 s quando comparado a 100%vVO2max (EI100% (91,9 ± 75,2s e a 120%vVO2max (EI120% (126,3 ± 29,4 s, porém sem diferença entre EI100% e EI120%. O t90VO2max somente apresentou diferença significante entre EI110% e EI120%. Portanto, conclui-se que durante exercício intermitente com razão 30s:15s, a intensidade de 110%vVO2max apresenta-se mais adequada para manter o VO2 próximo ou no VO2max por um tempo maior.The present study compared the time maintained above 90% (t90VO2max or 95% VO2max (t95VO2max in three different exercise intensities. After performing an incremental test to determine VO2max, eight physical education active students (23 ± 3 years performed three intermittent exercise sessions (100, 110 e 120% velocity of VO2max (vVO2max with ratio effort:recovery of 30s:15s. The t95%VO2max was significantly higher at 110%vVO2max (EI110% (218.1 ± 81.6s compared to 100% vVO2max (EI100% (91.9 ± 75.2s and 120%vVO2max (EI120% (126.3 ± 29.4s, but without differences between EI100% and EI120%. The t90%vVO2max was significantly different only between EI110% and 120%. Therefore, we conclude that during intermittent exercise with ratio 30s:15s, the intensity of 110%vVO2max appears more appropriate to maintain VO2max for a longer time.

  7. VO2 kinetics and metabolic contributions whilst swimming at 95, 100, and 105% of the velocity at VO2max.

    Science.gov (United States)

    Sousa, Ana C; Vilas-Boas, João P; Fernandes, Ricardo J

    2014-01-01

    A bioenergetical analysis of swimming at intensities near competitive distances is inexistent. It was aimed to compare the transient VO2 kinetics responses and metabolic contributions whilst swimming at different velocities around VO2max. 12 trained male swimmers performed (i) an incremental protocol to determine the velocity at VO2max (vVO2max) and (ii) three square wave exercises from rest to 95, 100, and 105% of vVO2max. VO2 was directly measured using a telemetric portable gas analyser and its kinetics analysed through a double-exponential model. Metabolic contributions were assessed through the sum of three energy components. No differences were observed in the fast component response (τ1--15, 18, and 16 s, A1--36, 34, and 37 mL · kg(-1) · min (-1), and Gain--32, 29, and 30 mL · min (-1) at 95, 100, and 105% of the vVO2max, resp.) but A2 was higher in 95 and 100% compared to 105% intensity (480.76 ± 247.01, 452.18 ± 217.04, and 147.04 ± 60.40 mL · min (-1), resp.). The aerobic energy contribution increased with the time sustained (83 ± 5, 74 ± 6, and 59 ± 7% for 95, 100, and 105%, resp.). The adjustment of the cardiovascular and/or pulmonary systems that determine O2 delivery and diffusion to the exercising muscles did not change with changing intensity, with the exception of VO2 slow component kinetics metabolic profiles.

  8. Prediction of VO2max in Children and Adolescents Using Exercise Testing and Physical Activity Questionnaire Data.

    Science.gov (United States)

    Black, Nate E; Vehrs, Pat R; Fellingham, Gilbert W; George, James D; Hager, Ron

    2016-01-01

    The purpose of this study was to evaluate the use of a treadmill walk-jog-run exercise test previously validated in adults and physical activity questionnaire data to estimate maximum oxygen consumption (VO2max) in boys (n = 62) and girls (n = 66) aged 12 to 17 years old. Data were collected from Physical Activity Rating (PA-R) and Perceived Functional Ability (PFA) questionnaires, a walk-jog-run submaximal treadmill exercise test, and a maximal graded exercise test. Regression analysis resulted in the development of 2 models to predict VO2max. Submaximal exercise test data were used to build the following model (R2 = .73; SEE = 4.59 mL + kg(- 1) + min(- 1)): VO2max (mL + kg(- 1) + min(- 1)) = 26.890+(5.877 × Gender; 0 = female; 1 = male) - (0.782 × Body Mass Index [BMI])+(0.438 × PFA Score) +(2.712 × Treadmill Speed; mph) +(0.746 × Age) +(0.449 × PA-R Score). Maximal exercise test data were used to build the following model (R2 = .83; SEE = 3.63 mL + kg(- 1) + min(- 1)): VO2max (mL + kg(- 1) + min(- 1)) = 10.716+(1.334 × Maximal Treadmill Grade) +(5.203 × Treadmill Speed; mph) +(3.494 × Gender; 0 = female; 1 = male) - (0.413 × BMI) +(0.249 × PFA). The results of this study demonstrate, for the first time, that regression equations that use both exercise data and physical activity questionnaire data can accurately predict VO2max in youth. The submaximal and maximal exercise tests that use self-selected treadmill speeds can be used to assess cardiorespiratory fitness of youth with a wide range of fitness levels.

  9. Comparison of Blood Cholesterol Profiles Before and After The Measurements of Maximum Aerobic Capacity (VO2max

    Directory of Open Access Journals (Sweden)

    Ar Rasyid Shadiqin

    2013-11-01

    Full Text Available This study is aimed to compare the blood cholesterol profile, before and after the measurement of maximum aerobic capacity (VO2max in the students of Jurusan Pendidikan Olahraga dan Kesehatan (JPOK pada Fakultas Keguruan dan Ilmu Pendidikan (FKIP Universitas Lambung Mangkurat Banjarmasin.Variables in this study consist of lipid profiles, including total cholesterol, high density lipoprotein (HDL, low density lipoprotein (LDL, triglyceride (TG and Maximum Aerobic Capacity (VO2max. The concept of VO2max according to Kent(1994:268: “maximum oxygen volume consumed per minute to show total work capacity, or volume per minute relative to body weight (ml/kg.min”. Operationally, VO2max referred in this study is the maximum volume of oxygen that can be consumed per minute, as measured at progressive run (Bleep Test.The method used in this study is pre-experimental with one group pretest-posttest design. This design implies that a group of subjects are treated for a specific period and the measurements are taken both pre and post.The results: There are changes in blood cholesterol profile after the measurement of maximum oxygen capacity (VO2max, shown by significant decrease of total cholesterol variable, increased HDL, and decreased LDL. Changes in triglyceride variable showed no significant decrease despite the statistic differences. Specific HDL sub-class increasing after exercise is a constructive lipoprotein sub-class whereas LDL is destructive lipoproteins sub-class that might damage the body. Therefore, an increase in HDL and decrease in LDL found in this study appears to be advantageous and consequently might alter the risk of coronary heart disease.

  10. Knee extensor fatigue threshold is related to whole-body VO2max.

    Science.gov (United States)

    de Ruiter, Cornelis J; Maas, Ellen A; Wesseling, Mariska G H; de Haan, Arnold

    2012-07-01

    Above a given exercise intensity, rapid muscle fatigue will occur. We explored the possibility of assessing torque threshold for peripheral fatigue during single-legged repetitive isometric knee extensor exercise. We hypothesized this fatigue threshold to be related to the general aerobic fitness level and the so-called "critical torque" (CT) established with a recently validated 5-min all-out test. Seventeen healthy men (VO(2max) = 44.7-69.6 mL·kg(-1)·min(-1)) performed six submaximal (20%-55% maximal voluntary contraction [MVC]) 5-min bouts of 60 repetitive contractions (3-s on, 2-s off). Torque was changed between bouts in steps of 5% MVC to estimate the highest intensity (fatigue threshold) at which average changes in rsEMG, EMG median power frequency, and tissue deoxygenation (near-infrared spectroscopy) of the three superficial knee extensor muscles were still test torque representing CT. Fatigue threshold (40.0% ± 8.1% MVC) was related (r(2) = 0.57, P test may be used to evaluate changes in endurance capacity of single muscle groups, without the necessity for all-out testing, which could be problematic with frail subjects.

  11. Aerobic Fitness Levels and Validation of a Non-Exercise VO2max Prediction Equation for HIV-Infected Patients on HAART

    Science.gov (United States)

    Sullivan, Katherine; Shikuma, Cecilia M.; Chow, Dominic; Cornelius, Elizabeth; Romine, Rebecca K.; Lindsey, Rachel A.; Stickley, Christopher D.; Kimura, Iris F.; Hetzler, Ronald K.

    2015-01-01

    Background Non-exercise (N-EX) questionnaires have been developed to determine maximal oxygen consumption (VO2max) in healthy populations. There are limited reliable and validated N-EX questionnaires for the HIV+ population that provide estimates of habitual physical activity and not VO2max. Objectives To determine how well regression equations developed previously on healthy populations, including N-EX prediction equations for VO2max and age-predicted maximal heart rates (APMHR), worked on an HIV+ population; and to develop a specific N-EX prediction equation for VO2max and APMHR for HIV+ individuals. Methods Sixty-six HIV+ participants on stable HAART completed 4 N-EX questionnaires and performed a maximal graded exercise test. Results Sixty males and 6 females were included; mean (SD) age was 49.2 (8.2) years; CD4 count was 516.0 ± 253.0 cells·mn−3; and 92% had undetectable HIV PCR. Mean VO2max was 29.2 ± 7.6 (range, 14.4–49.4) mL·kg−1·min−1. Despite positive correlations with VO2max, previously published N-EX VO2max equations produced results significantly different than actual VO2 scores (P VO2max values, R = 0.71, when compared to achieved VO2max (P = .53). Conclusion HIV+ individuals tend to be sedentary and unfit, putting them at increased risk for the development of chronic diseases associated with a sedentary lifestyle. Based on the level of error associated with utilizing APMHR and N-EX VO2max equations with HIV+ individuals, neither should be used in this population for exercise prescription. PMID:24710921

  12. A Reference Equation for Normal Standards for VO2 max: Analysis from the Fitness Registry and the Importance of Exercise National Database (FRIEND Registry).

    Science.gov (United States)

    Myers, Jonathan; Kaminsky, Leonard A; Lima, Ricardo; Chistle, Jeffrey; Ashley, Euan; Arena, Ross

    2017-04-01

    Existing normal standards for maximal oxygen uptake (VO2 max) are problematic because they tend to be population specific, lack normal distribution and portability, and are poorly represented by women. The objective of the current study was to apply the Fitness Registry and the Importance of Exercise: A National Data Base (FRIEND) Registry to improve upon previous regression formulas for normal standards for VO2 max using treadmill testing. Maximal treadmill tests were performed in 7783 healthy men and women (20-79years; maximal RER >1.0) from the FRIEND registry and a separate validation cohort of 1287 subjects. A regression equation for VO2 max was derived from the FRIEND registry and compared to the validation cohort and two commonly used equations (Wasserman and European). Age, gender, and body weight were the only significant predictors of VO2 max (multiple R=0.79, R(2)=0.62, p<0.001). The equation for predicting VO2 max was: [Formula: see text] Marked differences were observed in percentage predicted VO2 max achieved between commonly used reference equations, particularly among women, overweight and obese subjects. In the validation sample, the FRIEND equation closely paralleled measured VO2 max, with the validation group yielding a percent predicted VO2 max of 100.4% based on the FRIEND equation. An equation for age-predicted VO2 max derived from the FRIEND registry provided a lower average error between measured and predicted VO2 max than traditional equations, and thus may provide a more suitable normal standard relative to traditional equations.

  13. Relationship between velocity reached at VO2(max) and time-trial performances in elite Australian Rules footballers.

    Science.gov (United States)

    Lorenzen, Christian; Williams, Morgan D; Turk, Paul S; Meehan, Daniel L; Kolsky, Daniel J Cicioni

    2009-09-01

    Running velocity reached at maximal oxygen uptake (vVO2(max)) can be a useful measure to prescribe training intensity for aerobic conditioning. Obtaining it in the laboratory is often not practical, and average velocities from time trials are an attractive alternative. To date, the efficacies of such practices for team sport players are unknown. This study aimed to assess the relationship between vVO2(max) obtained in the laboratory against two time-trial estimates (1500 m and 3200 m). During the early preseason, elite Australian Rules football players (n = 23, 22.7 +/- 3.4 y, 187.7 +/- 8.2 cm, 75.5 +/- 9.2 kg) participated in a laboratory test on a motorized treadmill and two outdoor time trials. Based on average velocity the 1500-m time-trial performance (5.01 +/- 0.23 m x s(-1)) overestimated (0.36 m x s(-1), d = 1.75), whereas the 3200-m time trial (4.47 +/- 0.23 m x s(-1)) underestimated (0.17 m x s(-1), d = 0.83) the laboratory vVO2(max) (4.64 +/- 0.18 m x s(-1)). Despite these differences, both 1500-m and 3200-m time-trial performances correlated with the laboratory measure (r = -0.791; r = -0.793 respectively). Both subsequent linear regressions were of good fit and predicted the laboratory measure within +/- 0.12 m x s(-1). Estimates of vVO2(max) should not be used interchangeably, nor should they replace the laboratory measure. When laboratory testing is not accessible for team sports players, prescription of training intensity may be more accurately estimated from linear regression based on either 1500-m or 3200-m time-trial performance than from the corresponding average velocity.

  14. The reliability and validity of the Astrand nomogram and linear extrapolation for deriving VO2max from submaximal exercise data.

    Science.gov (United States)

    Macsween, A

    2001-09-01

    While the accepted measure of aerobic power remains the VO2max this test is extremely demanding even for athletes. There are serious practical and ethical concerns in attempting such testing in non-athletic or patient populations. An alternative method of measuring aerobic power in such populations is required. A limited body of work exists evaluating the accuracy of the Astrand-Ryhming nomogram and linear extrapolation of the heart rate/oxygen uptake plot. Issues exist in terms of both equipment employed and sample numbers. Twenty-five normal subjects (mean age 28.6, range 22-50) completed 52 trials (Bruce treadmill protocol) meeting stringent criteria for VO2max performance. Respiratory gases were measured with a portable gas analyser on a five-sec sample period. The data was analysed to allow comparison of the reliability and validity of linear extrapolations to three estimates of heart rate maximum with the Astrand nomogram prediction. Extrapolation was preferable yielding intraclass correlation co-efficients (ICC) of 0.9433 comparable to that of the observed VO2max at 0.9443 and a bias of -1.1 ml x min(-1) x kg(-1) representing a 2.19 percent underestimate. This study provides empirical evidence that extrapolation of submaximal data can be employed with confidence for both clinical monitoring and research purposes. With the use of portable equipment and submaximal testing the scope for future research in numerous populations and non-laboratory environments is considerably increased.

  15. Efeito da intensidade do exercício de corrida intermitente 30s:15s no tempo de manutenção no ou próximo do VO2max

    OpenAIRE

    Aguiar,Rafael Alves de; Schlickmann, Jardel; Turnes, Tiago; Caputo, Fabrizio [UNESP

    2013-01-01

    O presente estudo comparou o tempo mantido acima de 90% (t90VO2max) e de 95% VO2max (t95VO2max) em três diferentes intensidades de exercício. Após a realização de um teste incremental para determinar o VO2max, oito estudantes de educação física ativos (23 ± 3 anos) executaram três sessões de exercícios intermitentes (100, 110 e 120% da velocidade do VO2max (vVO2max)) com razão esforço:recuperação de 30s:15s. O t95VO2max foi significantemente maior em 110%vVO2max (EI110%) (218,1 ± 81,6 s) quan...

  16. High-intensity interval training every second week maintains VO2max in soccer players during off-season.

    Science.gov (United States)

    Slettaløkken, Gunnar; Rønnestad, Bent R

    2014-07-01

    Reduced endurance training among semiprofessional soccer players during off-season may have negative effect on game performance during the competition season. This negative effect can be prevented by adding high-intensity interval training (HIT) to normal activity. In this study, we want to compare 2 different frequencies of HIT (5 bouts of 4 minutes on 87-97% peak heart rate) session on maintenance of aerobic fitness among semiprofessional soccer players during a 6-week off-season period. Seventeen male players at second and third highest soccer division in Norway participated. The subjects were randomized into 1 HIT session every second week (HIT 0.5) or 1 HIT session per week (HIT 1). All participants performed a 20-m shuttle run test and a maximal oxygen uptake (VO2max) test on treadmill before and after the training intervention. VO2max (HIT 0.5, 63.4 ± 5.9 ml·kg-1·min-1; HIT 1, 65.6 ± 2.1 ml·kg-1·min-1) and 20-m shuttle run performance (HIT 0.5, 2335 ± 390 m, HIT 1, 2531 ± 106 m) were not different between the groups before the training intervention. VO2max was maintained after the training intervention in both HIT 0.5 and HIT 1 (64.0 ± 5.9 ml·kg-1·min-1 and 64.3 ± 1.3 ml·kg-1·min-1, respectively). There was a reduction in distance covered during the 20-m shuttle run test in HIT 1 and when groups were pooled (-7.9 ± 5.7% and -6.4 ± 7.9%, respectively, p ≤ 0.05). In conclusion, HIT 1 did not maintain VO2max better than HIT 0.5 when added to normal off-season activity. However, performance in 20-m shuttle run, which is a more soccer-specific fitness test than VO2max test, was slightly reduced when both groups was pooled.

  17. Correlação entre as medidas direta e indireta do VO2max em atletas de futsal Correlación entre las medidas directa e indirecta del VO2max en atletas de futsal Correlation between direct and indirect VO2max measurements in indoor soccer players

    Directory of Open Access Journals (Sweden)

    Anna Myrna Jaguaribe de Lima

    2005-06-01

    Full Text Available A importância das qualidades morfofuncionais na melhora do rendimento nos esportes aumentou o interesse no aprimoramento dos níveis de aptidão física dos atletas. No entanto, há poucos estudos sobre as variáveis fisiológicas do futsal disponíveis na literatura científica mundial. Dessa forma, o objetivo deste estudo foi verificar a existência de correlação entre os testes de medida direta e indireta do VO2max, em jogadores de futsal. Foram analisados 13 jogadores de futsal, com idade de 18,6 ± 1,9 anos, altura igual a 177,1 ± 3,5cm, peso de 68,5 ± 9,5kg, índice de massa corporal (IMC de 21,7 ± 2,3kg/m². Para medida direta do VO2max foi utilizado o sistema ergoespirométrico computadorizado (VO-2000, Aerosport, Medgraphics, St. Paul, Minnesota e para mensuração indireta do VO2max foi realizado o teste de campo de 3.200m. A análise estatística foi elaborada através do teste t de Student para amostras pareadas e pelo coeficiente de correlação de Pearson. Os valores de VO2max obtidos no teste de medida direta não apresentaram diferenças significativas em relação à medida indireta (62,8 ± 10,1 vs. 58,5 ± 8,5ml/kg/min, respectivamente. Quando correlacionados os valores de VO2max obtidos em ambos os testes, observou-se forte correlação (r = 0,72. Em conclusão, os testes de medida indireta apresentam boa aceitação para os atletas de futsal, tendo em vista a alta correlação com os testes de medida direta, o baixo custo de sua aplicação e o fornecimento de informações importantes que podem auxiliar na prescrição e no acompanhamento do treinamento.La importância de las cualidades morfo-funcionales en la mejora del rendimiento en los deportes aumentó el interes en el acondicionamiento de los niveles de aptitud física de los atletas. En tanto, hay pocos estudios sobre las variables fisiológicas del futsal disponibles en la literatura mundial. De esta forma, el objetivo del estudio fué verificar la existencia

  18. The role of haemoglobin mass on VO(2)max following normobaric 'live high-train low' in endurance-trained athletes

    DEFF Research Database (Denmark)

    Robach, Paul; Siebenmann, Christoph; Jacobs, Robert A

    2012-01-01

    It remains unclear by which mechanism 'live high-train low' (LHTL) altitude training increases exercise performance. Haematological and skeletal muscle adaptations have both been proposed. To test the hypotheses that (i) LHTL improves maximal oxygen uptake (VO(2)max) and (ii) this improvement...... is related to hypoxia-induced increases in total haemoglobin mass (Hb(mass)) and not to improved maximal oxidative capacity of skeletal muscle, we determined VO(2)max before LHTL and after LHTL, before and after the altitude-induced increases in Hb(mass) (measured by carbon-monoxide rebreathing) had been...... to 3000 m altitude (LHTL, n=10). Four-week LHTL did not increase VO(2)max, irrespective of treatment (LHTL: 1.5%; placebo: 2.0%). Hb(mass) was slightly increased (4.6%) in 5 (of 10) LHTL subjects but this was not accompanied by a concurrent increase in VO(2)max. In the subjects demonstrating an increase...

  19. Concurrent validity of the non-exercise based VO2max prediction equation using percentage body fat as a variable in asian Indian adults

    Science.gov (United States)

    2012-01-01

    Background Aerobic capacity (VO2max) is highly dependent upon body composition of an individual and body composition varies with ethnicity. The purpose of this study was to check the concurrent validity of the non-exercise prediction equation developed by Jackson and colleagues (1990) using percentage body fat as a variable in Asian Indian adults. Methods One hundred twenty college-aged participants (60 male, 60 female, mean age 22.02 ± 2.29 yrs) successfully completed a maximal graded exercise test (GXT) on a motorized treadmill to assess VO2max. VO2max was then estimated by the non-exercise prediction equation developed by Jackson and colleagues (1990) using percentage body fat. Percentage body fat was calculated by three different models (Sandhu et al’s fat mass equation, Durnin-womersley’s 4 site percentage body fat and Jackson & Pollock’s 4 site percentage body fat) and was used in the above equation. The results of VO2max obtained using “gold standard” treadmill methods were then compared with the three results of VO2max obtained by Jackson et al’s equation (using three different models to calculate percentage body fat) and it was determined which equation is best suited to determine percentage body fat and in turn VO2 max for Indian population. Results Jackson et al’s prediction equation overpredicts VO2max in Asian Indian subjects who have a lower VO2max (33.41 ± 14.39 ml/kg/min) than those reported in other age matched populations. percentage body fats calculated by the three equations were significantly different and the correlation coefficient (r) between VO2max calculated by Jackson and colleagues (1990) using Sandhu et al’s equation for percentage body fat with VO2 max calculated using treadmill (gold standard) (r = .817) was found slightly more significantly correlated than the other two equations and was not statistically different from the measured value. Conclusions This study proves that VO2max equation using

  20. Comparison of the IPAQ-A and actigraph in relation to VO2max among European adolescents: the HELENA study.

    Science.gov (United States)

    Ottevaere, Charlene; Huybrechts, Inge; De Bourdeaudhuij, Ilse; Sjöström, Michael; Ruiz, Jonatan R; Ortega, Francisco B; Hagströmer, Maria; Widhalm, Kurt; Molnár, Dénes; Moreno, Luis A; Beghin, Laurent; Kafatos, Anthony; Polito, Angela; Manios, Yannis; Mártinez-Gómez, David; De Henauw, Stefaan

    2011-07-01

    The purpose was to compare data obtained from a modified, long, self-administered version of the International Physical Activity Questionnaire (IPAQ-A) with objective data obtained in parallel from Actigraph accelerometers, and VO(2)max in adolescents. The study comprised a total of 2018 adolescents (46% male) from ten European cities participating in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study. Physical activity was assessed over seven consecutive days by accelerometry and expressed as min/day of moderate, vigorous, and moderate to vigorous (MVPA) physical activity (PA). PA was also assessed with the IPAQ-A. VO(2)max was estimated from a 20-m shuttle run test. Poor to fair correlations between the two methodologies were found for the whole study sample and when stratified by age and gender (r(s) = 0.08-0.26, p < 0.01). On average, the self-reported time spent in moderate PA was higher compared to the time measured with the accelerometer, while the differences between both instruments were less clear for vigorous intensity. Adolescents reporting high levels of PA (3rd tertile IPAQ-A) also showed higher levels of PA (accelerometers) in all the study variables (moderate, vigorous and MVPA), compared to adolescents reporting low PA (1st tertile IPAQ-A) (all p < 0.001). Both methods were moderately correlated with estimated VO(2)max. Within the HELENA-study, the IPAQ-A showed the modest comparability with the accelerometer data for assessing PA in each intensity level and was the highest for vigorous intensity. Both instruments are able to detect the adolescents with the highest cardio respiratory fitness, which are the most active adolescents. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

  1. The effect of limited handrail support on total treadmill time and the prediction of VO2 max.

    Science.gov (United States)

    Manfre, M J; Yu, G H; Varmá, A A; Mallis, G I; Kearney, K; Karageorgis, M A

    1994-08-01

    Holding onto the front handrail during treadmill testing significantly increases total treadmill time (TT) and predicted VO2max when compared with tests without front handrail support. By limiting the amount of handrail support to the tips of two fingers of one hand, the difference in TT can be substantially reduced. In the present study, the difference in TT between tests with and without handrail support for healthy men was not significantly different. However, this was not true for healthy women and for male patients with coronary artery disease and myocardial infarction.

  2. The impact of decreasing cutoff values for maximal oxygen consumption (VO2max) in the decision-making process for candidates to lung cancer surgery

    Science.gov (United States)

    Gatani, Tindaro; Di Maio, Massimo; Meoli, Ilernando; La Rocca, Antonello; Martucci, Nicola; La Manna, Carmine; Stefanelli, Francesco

    2013-01-01

    Background Maximal oxygen consumption (VO2max) is considered a decisive test for risk prediction in patients with borderline cardiopulmonary reserve. Guidelines have adopted decreasing VO2max cut-off values to define operability within acceptable mortality and morbidity limits. We wanted to investigate how the adoption of decreasing VO2max cut-off-values assessment contributed to better select lung surgery candidates. Methods One hundred and nineteen consecutive surgical candidates have been prospectively analyzed as a sample population. Preoperative work-up included spirometry and transfer factor (DLco); irrespective of the spirometric values, these patients were subjected to VO2max assessment. Surgical eligibility was decided by the same surgeon throughout the series. In the postoperative period, overall mortality and the occurrence of any, major or minor complications was recorded and graded according to the Common Terminology Criteria for Adverse Events v.4.3. Results Three arbitrary cut-offs were introduced at 15, 14 and 12 mL.kg-1.min-1. Notably, 15 and 12 mL.kg-1.min-1 correlated with percentage VO2max values of 50% and 35% of predicted (PVO2max less than 35% (P=0.0017) and CTCAE >2 (P=0.0457) emerged as significant predictors of survival after surgery. Conversely on logistic regression analysis, age over 70 years (P=0.03) and pneumonectomy (P=0.001), but not VO2max cut-off values, were significant predictors of major (CTCAE >2) morbidity. Conclusions Since VO2max is increasingly used to contribute to risk prediction for the individual patient, surgeons need to be advised that the concept of a definitive, generalized cut-off value for VO2max is probably a contradiction in terms. Patient-specific VO2max values are more likely to contribute to risk assessment since they may reflect the primarily affected component among the determinants of maximal oxygen consumption. Whether patient-specific VO2max should be routinely used by surgeons to define operability for

  3. Very short (15s-15s) interval-training around the critical velocity allows middle-aged runners to maintain VO2 max for 14 minutes.

    Science.gov (United States)

    Billat, V L; Slawinksi, J; Bocquet, V; Chassaing, P; Demarle, A; Koralsztein, J P

    2001-04-01

    The purpose of this study was to compare the effectiveness of three very short interval training sessions (15-15 s of hard and easier runs) run at an average velocity equal to the critical velocity to elicit VO2 max for more than 10 minutes. We hypothesized that the interval with the smallest amplitude (defined as the ratio between the difference in velocity between the hard and the easy run divided by the average velocity and multiplied by 100) would be the most efficient to elicit VO2 max for the longer time. The subjects were middle-aged runners (52 +/- 5 yr, VO2 max of 52.1 +/- 6 mL x min(-1) x kg(-1), vVO2 max of 15.9 +/- 1.8 km x h(-1), critical velocity of 85.6 +/- 1.2% vVO2 max) who were used to long slow distance-training rather than interval training. They performed three interval-training (IT) sessions on a synthetic track (400 m) whilst breathing through the COSMED K4b2 portable metabolic analyser. These three IT sessions were: A) 90-80% vVO2 max (for hard bouts and active recovery periods, respectively), the amplitude= (90-80/85) 100=11%, B) 100-70% vVO2 max amplitude=35%, and C) 60 x 110% vVO2 max amplitude = 59%. Interval training A and B allowed the athlete to spend twice the time at VO2 max (14 min vs. 7 min) compared to interval training C. Moreover, at the end of interval training A and B the runners had a lower blood lactate than after the procedure C (9 vs. 11 mmol x l(-1)). In conclusion, short interval-training of 15s-15s at 90-80 and 100-70% of vVO2 max proved to be the most efficient in stimulating the oxygen consumption to its highest level in healthy middle-aged long-distance runners used to doing only long slow distance-training.

  4. Influência do estado nutricional e do VO2max nos níveis de adiponectina em homens acima de 35 anos Influencia del Estado Nutricional y del VO2max en los Niveles de Adiponectina en Hombres que superan los 35 Años Influence of nutritional status and VO2max on adiponectin levels in men older than 35 years

    Directory of Open Access Journals (Sweden)

    Eduardo Camillo Martinez

    2011-06-01

    Full Text Available FUNDAMENTO: A adiponectina é considerada importante fator na patogênese das doenças cardiovasculares e metabólicas, por suas propriedades antiaterogênicas e antiinflamatórias. Poucos estudos, entretanto, sugerem a existência de relação direta entre os níveis de adiponectina e os níveis de condicionamento cardiorrespiratório e atividade física. OBJETIVO: Verificar a influência do estado nutricional e do condicionamento cardiorrespiratório nos níveis plasmáticos de adiponectina em homens adultos. MÉTODOS: Foram avaliados 250 sujeitos, homens, todos militares da ativa do Exército Brasileiro (42,6 ± 4,8 anos. Foram mensurados os níveis plasmáticos de adiponectina, massa corporal, estatura, circunferência da cintura (CC, percentual de gordura por pesagem hidrostática e VO2max por ergoespirometria. Um questionário foi utilizado para obter as características do treinamento físico realizado pelos sujeitos. RESULTADOS: Na amostra, 121 (48% sujeitos apresentaram sobrepeso e 36 (14% eram obesos. Ainda, 66 sujeitos (27% apresentaram percentual de gordura maior que 25% e 26.7% apresentaram CC > 94 cm. Sujeitos com sobrepeso e obesidade apresentaram valores significativamente menores de adiponectina em relação aqueles com estado nutricional normal. Sujeitos no mais alto tercil de VO2max apresentaram níveis de adiponectina mais altos que os demais. Os níveis de adiponectina estiveram positivamente correlacionados com o tempo total de treinamento físico semanal e com o VO2max e inversamente correlacionados com os valores de massa corporal, IMC e CC. A correlação dos níveis de adiponectina e do VO2max não permaneceu significante após controlada pelo IMC e CC. CONCLUSÃO: Sujeitos com melhor condicionamento cardiorrespiratório e com estado nutricional normal parecem apresentar níveis mais saudáveis de adiponectina.FUNDAMENTO: La adiponectina es considerada un importante factor en la patogénesis de las enfermedades

  5. 补服乳清蛋白对人体最大吸氧量的影响%Effects of supplementation Whey-protein On VO2max

    Institute of Scientific and Technical Information of China (English)

    任秀红; 张翔; 杨多多

    2012-01-01

    This study examined the effects of whey-protein, or placebo on VO2max, researched effects of intaking whey protein on aerobic exercise power as well. Method: twelve healthy males who major in PE participated in this research study. Single-blind design was employed, participants performed three times increasing the load continuous on anaerobic power cycling which lasted for 3 minutes followed by consumption of 7g whey-protein, 14g whey-protein or placebo 30 minutes before exercise. Results: There was significantly different between supplementation 7g whey-protein and placebo(p〈.05), similarly there was very significantly different between intaklng 7g whey-protein and 14g whey-protein(p〈.01).Conclusion: supplementation different mount of whey-protein has different effects on VO2max, Maybe supplementation whey-protein will effect the power of aerobic exercise.%目的:研究补服不同量的乳清蛋白对人体最大吸氧量的变化,探讨补服乳清蛋白对人体有氧运动能力的影响。方法:采用单盲实验法,体育系12名健康男性大学生作为被试,每次(共3次)补服不同的补剂,然后在无氧功率自行车上进行3个连续三分钟的递增负荷运动,作自身对照。结果:补服7g和14g乳清蛋白与安慰剂相比最大吸氧量水平都有不同程度的变化,补服7g乳清蛋白与安慰剂相比差异性显著,p〈0.05,补服14g乳清蛋白与安慰剂相比差异性非常显著p〈0.01。结论:(1)补服不同量的乳清蛋白都不同程度影响人体的最大吸氧量水平;(2)说明乳清蛋白的补服对人体有氧运动能力有一定影响。

  6. Living and training in moderate hypoxia does not improve VO2 max more than living and training in normoxia.

    Science.gov (United States)

    Henderson, K K; Clancy, R L; Gonzalez, N C

    2001-06-01

    The objective of these experiments was to determine whether living and training in moderate hypoxia (MHx) confers an advantage on maximal normoxic exercise capacity compared with living and training in normoxia. Rats were acclimatized to and trained in MHx [inspired PO2 (PI(O2)) = 110 Torr] for 10 wk (HTH). Rats living in normoxia trained under normoxic conditions (NTN) at the same absolute work rate: 30 m/min on a 10 degrees incline, 1 h/day, 5 days/wk. At the end of training, rats exercised maximally in normoxia. Training increased maximal O2 consumption (VO2 max) in NTN and HTH above normoxic (NS) and hypoxic (HS) sedentary controls. However, VO2 max and O2 transport variables were not significantly different between NTN and HTH: VO2 max 86.6 +/- 1.5 vs. 86.8 +/- 1.1 ml x min(-1) x kg(-1); maximal cardiac output 456 +/- 7 vs. 443 +/- 12 ml x min(-1) x kg(-1); tissue blood O2 delivery (cardiac output x arterial O2 content) 95 +/- 2 vs. 96 +/- 2 ml x min(-1) x kg(-1); and O2 extraction ratio (arteriovenous O2 content difference/arterial O2 content) 0.91 +/- 0.01 vs. 0.90 +/- 0.01. Mean pulmonary arterial pressure (Ppa, mmHg) was significantly higher in HS vs. NS (P < 0.05) at rest (24.5 +/- 0.8 vs. 18.1 +/- 0.8) and during maximal exercise (32.0 +/- 0.9 vs. 23.8 +/- 0.6). Training in MHx significantly attenuated the degree of pulmonary hypertension, with Ppa being significantly lower at rest (19.3 +/- 0.8) and during maximal exercise (29.2 +/- 0.5) in HTH vs. HS. These data indicate that, despite maintaining equal absolute training intensity levels, acclimatization to and training in MHx does not confer significant advantages over normoxic training. On the other hand, the pulmonary hypertension associated with acclimatization to hypoxia is reduced with hypoxic exercise training.

  7. [Pre-operative screening tests for lung cancer using the analysis of expired gas with exercise testing--principally VO2 max/m2].

    Science.gov (United States)

    Nagamatsu, Y; Ono, H; Hiraki, H; Matsuo, T; Mitsuoka, M; Takamori, S; Hayashi, A; Yamana, H; Hayashida, R; Kakegawa, T

    1994-10-01

    The analysis of expired gas with exercise testing was conducted preoperatively with lung cancer patients in order to examine the relationship between maximum oxygen consumption (VO2 max) and postoperative complications, determining the cut-off of VO2 max/m2. The usefulness of the test as a preoperative screening test for both pulmonary ventilation and circulation was evaluated in comparison to pulmonary ventilation tests with spirometry and pulmonary circulation tests with Swan-Ganz catheter. Preoperative VO2 max/m2 was calculated from VO2 max in 111 patients with lung cancer who underwent lobectomy of more than one lobe. Also preoperatively conducted were pulmonary ventilation tests by spirometry and pulmonary circulation tests using the Swan-Ganz catheter to measure VC, %VC, FEV1.0, FEV1.0%, mean pulmonary arterial pressure (PPA) and cardiac output coefficient (C.I.). Form theses measurements, VC/m2, FEV1.0/m2 and total pulmonary vascular resistance (TPVR) were calculated. After the cut-off values of VO2 max/m2 were set tentatively at three stages, 600, 650 and 700 ml/min/m2 based on the incidence of postoperative complications, the 111 patients were divided into two groups in each cut-off value; one with VO2 max/m2 greater than the cut-off value and the other less than the cut-off value. Comparison of measurements obtained by spirometry between the two groups disclosed significant differences (p < 0.001) in VC/m2, %VC and FEV1.0/m2 in all cut-off values. Similarly, comparison of measurements obtained using the Swan-Ganz catheter between the two groups yielded significant differences (p < 0.05 to p < 0.01) in PPA and TPVR in all cut-off values.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. The Effect of Training Intensity on VO2max in Young Healthy Adults: A Meta-Regression and Meta-Analysis

    OpenAIRE

    SCRIBBANS, TRISHA D.; VECSEY, STEPHAN; Hankinson, Paul B.; Foster, William S.; Brendon J Gurd

    2016-01-01

    Exercise training at a variety of intensities increases maximal oxygen uptake (VO2max), the strongest predictor of cardiovascular and all-cause mortality. The purpose of the present study was to perform a systematic review, meta-regression and meta-analysis of available literature to determine if a dose-response relationship exists between exercise intensity and training-induced increases in VO2max in young healthy adults. Twenty-eight studies involving human participants (Mean age: 23±1 yr; ...

  9. PELATIHAN LARI SIRKUIT 2 X 10 MENIT DAN PELATIHAN LARI KONTINYU 2 X 10 MENIT DAPAT MENINGKATKAN VO2 MAX TAEKWONDOIN PUTRA KABUPATEN MANGGARAI - NTT

    Directory of Open Access Journals (Sweden)

    Regina Sesilia Noy

    2014-08-01

    Full Text Available VO2 max is very important in everyday life, so as to facilitate any physicalactivity, specially for athletes in order to achieve maximum performance. In aneffort to increase VO2 max training should be carried out regularly, measured andplanned. This study aims to determine the increase in VO2 max through circuittraining run and run continuously. The sample is taekwondoin son Manggarai-NTTwith an average age of 15 years. This study is an experimental study with the studydesign used was Randomized Pre and Post Test Group desigen. With a totalsample of 7 people in each group. Samples were randomly selected. Treatmentgroup 1 (KP1 given training run circuit 2 x 10 minute and Treatment Group 2(KP2 are given continuous training run 2 x 10 minute. Training carried out for 6weeks with a frequency of four times a week starting at 17:00 to 18:00 pm locatedat Frans Sales Lega Airport Manggarai-NTT. The analysis showed an increase inVO2 max was significantly (p <0.05 against both groups fled. In both groups thecircuit run by Pulse Oxymeter and Norma Cooper an increase in VO2 max with p<0.05, as well as a continuous run either by Pulse Oxymeter and Norma Cooperwith an increase in VO2 max value of p <0.05. The results of this analysis meansthat either the training or circuit training run run continuously to improve VO2max. Based on a comparison of test data by an independent test after training inboth groups either by Pulse Oxymeter and Norma Cooper in get p values > 0.05, orthere is no significant difference. Based on these results it can be concluded thatthe run circuit training and continuous training run together can increase VO2 maxand there was no significant difference. The results of this study are expected toincrease the knowledge of coaches, teachers and taekwondoin to perform trainingon a regular basis and are also expected to do similar research that examines VO2max with different training.

  10. Evaluation of Maximal Oxygen Uptake (V02max) and Submaximal Estimates of VO2max Before, During and After Long Duration ISS Missions

    Science.gov (United States)

    Moore, Alan; Evetts, Simon; Feiveson, Alan; Lee, Stuart; McCleary, Frank; Platts, Steven

    2009-01-01

    NASA's Human Research Program Integrated Research Plan (HRP-47065) serves as a road-map identifying critically needed information for future space flight operations (Lunar, Martian). VO2max (often termed aerobic capacity) reflects the maximum rate at which oxygen can be taken up and utilized by the body during exercise. Lack of in-flight and immediate postflight VO2max measurements was one area identified as a concern. The risk associated with not knowing this information is: Unnecessary Operational Limitations due to Inaccurate Assessment of Cardiovascular Performance (HRP-47065).

  11. Comparison of VO2 Max Prediction Value, Physiological Response, and Borg Scale between 12-Minute and 3200-Meter Run Fitness Tests among Indonesian Army Soldiers

    Directory of Open Access Journals (Sweden)

    Maulidi Abdillah

    2016-09-01

    Full Text Available Objective: To compare the VO2 max and physiological responses between 12-minute and 3200-meter run fitness tests. Methods: The subjects were 40 soldiers aged 18–21 years old of the Infantry Battalion 303/SSM of Cikajang, Garut, West Java, Indonesia. The 12-minute and 3200-meter run fitness tests were conducted with one week resting period. The measurement of the VO2 max prediction was based on each of the formulations and the measurement of physiological response included blood pressure, heart rate, respiratory rate, Borg scale and oxygen saturation before and after the tests. This study used a cross-sectional method while the data were analyzed statistically using t-test (p=0.05. Results: The results showed that the VO2 max prediction in 12-minute run fitness test was 52.046±2.980 mL/KgBB/min and the 3200-meter run test was 55.323±3.238 mL/KgBB/min. The value was statistically significant (p=0.008. There was no significant difference in the physiological response in both tests, except the SpO2 parameter after the tests (p=0.021. Conclusions: There is a significant difference in VO2 max prediction between 12 minutes and 3200 meter run test. No significant difference was found in the physiological response in both tests, except the SpO2 parameter.

  12. Verification criteria for the determination of Vo2 MAX in the field.

    Science.gov (United States)

    Sánchez-Otero, Tania; Iglesias-Soler, Eliseo; Boullosa, Daniel A; Tuimil, José L

    2014-12-01

    The purpose of this study was to evaluate if a verification test (VT) performed in the field offers more confident results than do traditional criteria in the determination of maximal oxygen uptake ((Equation is included in full-text article.)). Twelve amateur runners (age, 36.6 ± 6.6 years) performed a maximal graded field test and after 15 minutes of passive recovery a supramaximal test to exhaustion at 105% of their velocity associated with (Equation is included in full-text article.)(v(Equation is included in full-text article.)). Traditional criteria and 2 different verification criteria were evaluated. Verification criteria were (a) maximal oxygen uptake achieved in the VT ((Equation is included in full-text article.)) must be ≤5% higher than (Equation is included in full-text article.), and (b) no significant differences of means between tests. All participants met the first verification criterion although significant differences were found between (Equation is included in full-text article.)and (Equation is included in full-text article.)(59.4 ± 5.1 vs. 56.2 ± 4.7 ml·kg·min, p max) were satisfied by 75, 66, 92, and 66 of the participants, respectively. Kappa coefficients gave a significant and substantial agreement beyond chance between traditional criteria (p max being the more stringent criteria for amateur runners. A verification protocol in the field using the criterion based on individual analysis is recommended.

  13. Actual Versus Predicted Cardiovascular Demands in Submaximal Cycle Ergometer Testing.

    Science.gov (United States)

    Hoehn, Amanda M; Mullenbach, Megan J; Fountaine, Charles J

    The Astrand-Rhyming cycle ergometer test (ARCET) is a commonly administered submaximal test for estimating aerobic capacity. Whereas typically utilized in clinical populations, the validity of the ARCET to predict VO2max in a non-clinical population, especially female, is less clear. Therefore, the purpose of this study was to determine the accuracy of the ARCET in a sample of healthy and physically active college students. Subjects (13 females, 10 males) performed a maximal cycle ergometer test to volitional exhaustion to determine VO2max. At least 48 hours later, subjects performed the ARCET protocol. Predicted VO2max was calculated following the ARCET format using the age corrected factor. There was no significant difference (p=.045) between actual (41.0±7.97 ml/kg/min) and predicted VO2max (40.3±7.58 ml/kg/min). When split for gender there was a significant difference between actual and predicted VO2 for males, (45.1±7.74 vs. 42.7±8.26 ml/kg/min, p=0.029) but no significant difference observed for females, (37.9±6.9 vs. 38.5±6.77 ml/kg/min, p=0.675). The correlation between actual and predicted VO2 was r=0.84, pVO2max in a healthy college population of both male and female subjects. Implications of this study suggest the ARCET can be used to assess aerobic capacity in both fitness and clinical settings where measurement via open-circuit spirometry is either unavailable or impractical.

  14. Validity of arm-leg elliptical ergometer for VO2max analysis.

    Science.gov (United States)

    Brown, Andrew B; Kueffner, Tannin E; OʼMahony, Erin C; Lockard, Michael M

    2015-06-01

    Maximal oxygen consumption ((Equation is included in full-text article.)) can be determined through multiple exercise modalities intended to elicit an individual's maximal aerobic exertion. Uphill treadmill running is considered the best modality for measuring (Equation is included in full-text article.). Previous studies have examined correlations between treadmill and elliptical ergometer tests as well as the cycle ergometer, but none of the studies use an arm-leg elliptical ergometer (ALE). The purpose of this study was to develop an ALE (Equation is included in full-text article.)testing protocol and determine whether ALE produces valid (Equation is included in full-text article.)values as compared with the treadmill. Twelve undergraduate students (mean age: 20.8 years) completed 2 (Equation is included in full-text article.)tests, 1 on a treadmill and 1 on ALE. (Equation is included in full-text article.)correlation between ALE and treadmill was examined, and paired t-tests were run for (Equation is included in full-text article.)and maximum heart rate (HRmax). A strong positive correlation was found between ALE and treadmill (Equation is included in full-text article.)values (r = 0.84; p Equation is included in full-text article.)values; however, HRmax values were higher on the treadmill than ALE (p = 0.003). Although future research is needed to examine the observed differences in HRmax between the 2 testing modalities and gender differences in muscle recruitment patterns, the results of this study suggest that ALE is a valid modality for (Equation is included in full-text article.)testing. This will be particularly valuable as a clinical tool to assess (Equation is included in full-text article.)in populations requiring low-impact exercise.

  15. How to Be 80 Year Old and Have a VO2max of a 35 Year Old

    Directory of Open Access Journals (Sweden)

    Trine Karlsen

    2015-01-01

    Full Text Available Background. To discuss the cardiovascular and pulmonary physiology and common risk factors of an 80-year-old man with a world record maximal oxygen uptake of 50 mL·kg−1·min−1. Methods. Case report. Results. His maximal oxygen uptake of 3.31 L·min−1, maximal heart rate of 175 beats·min−1, and maximal oxygen pulse of 19 mL·beats−1 are high. He is lean (66.6 kg and muscular (49% skeletal muscle mass. His echo parameters of mitral flow (left ventricular filling, E = 82 cm·s−1 and E/A = 1.2 were normal for 40- to 60-year-old men. Systolic and diastolic function increased adequately during exercise, with no increase in left ventricular filling pressure. He has excellent pulmonary function (FVC = 4.31 L, FEV1 = 3.41, FEV1/FVC = 0.79, and DLCO = 12.0 Si1 and normal FMD and blood volumes (5.8 L. He has a high level of daily activity (10,900 steps·day−1 and 2:51 hours·day−1 of physical activity and a lifelong history of physical activity. Conclusion. The man is in excellent cardiopulmonary fitness and is highly physically active. His cardiac and pulmonary functions are above expectations for his age, and his VO2max is comparable to that of an inactive 25-year-old and of a normal, active 35-year-old Norwegian man.

  16. Predição da potência aeróbia (VO2máx de crianças e adolescentes em teste incremental na esteira rolante Prediction of aerobic power (VO2max of children and adolescents during an incremental treadmill test

    Directory of Open Access Journals (Sweden)

    Fabiana Andrade Machado

    2013-03-01

    Full Text Available O consumo máximo de oxigênio (VO2máx é a quantidade máxima de energia que pode ser produzida pelo metabolismo aeróbio em determinada unidade de tempo, podendo ser determinado direta ou indiretamente através de equações preditivas. O objetivo deste trabalho foi elaborar uma equação preditiva específica para determinar o VO2máx de meninos de 10 a 16 anos. Quarenta e dois meninos realizaram teste ergoespirométrico de corrida em esteira rolante com velocidade inicial de 9 km/h até exaustão voluntária. Através da regressão linear múltipla foi possível desenvolver a seguinte equação para a determinação indireta do VO2máx: VO2máx (ml/min = -1574,06 + (141,38 x Vpico + (48,34 * Massa corporal, com erro padrão de estimativa = 191,5 ml/min (4,10 ml/kg/min e o coeficiente de determinação = 0,934. Sugerimos que esta é uma fórmula adequada para predizer o VO2máx para esta população.The maximal oxygen uptake (VO2max is the maximal quantity of energy that can be produced by the aerobic metabolism in certain time unity. It can be determined direct or indirectly by predictive equations. The objective of this study was to make a specific predictive equation to determine the VO2max from boys aged 10-16 years-old. Forty-two boys underwent a treadmill running ergospirometric test, with the initial velocity set at 9 km/h, until voluntary exhaustion. By the multiple linear regression was possible to develop the following equation for the indirect determination of the VO2max: VO2max (ml/min = -1574.06 + (141.38 x Vpeak + (48.34 * Body mass, with standard error of estimate = 191.5 ml/min (4.10 ml/kg/min and coefficient of determination = 0.934. We suggest that this formula is appropriate to predict VO2max for this population.

  17. The Effects of 8-week Nigella sativa Supplementation and Aerobic Training on Lipid Profile and VO2 max in Sedentary Overweight Females.

    Science.gov (United States)

    Farzaneh, Esmail; Nia, Farhad Rahmani; Mehrtash, Mohammad; Mirmoeini, Fatemeh Sadat; Jalilvand, Mohammad

    2014-02-01

    Regular moderate intensity physical activity and lipid lowering effects of Nigella sativa (N. sativa) supplementation may be appropriate management for sedentary overweight females. Therefore, the aim of the present study was to examine the effects of long-term N. sativa supplementation and aerobic training on lipid profile and maximal oxygen consumption (VO2 max) in sedentary overweight females. In this randomized, double-blind, controlled trial, which was conducted in Kerman city (Iran), 20 sedentary overweight females were divided into two groups and assigned to N. sativa supplementation (N. sativa capsules) or a placebo for the 8 weeks, both groups participated in an aerobic training program (3 times/week). Each N. sativa capsule contained 500 ± 10 mg N. sativa crushed seeds and subjects had to take 2 g N. sativa per day for 8 weeks. Blood lipids and VO2 max were determined at baseline and at the end of 8 weeks. N. sativa supplementation lowered total cholesterol (TC) (P high density lipoprotein (HDL) and VO2 max (P training program lowered TC (P training program and N. sativa supplementation lowered LDL and HDL (P training plus N. sativa supplementation have a synergistic effect in improve profile lipid parameters.

  18. A maximal cycle test with good validity and high repeatability in adults of all ages

    DEFF Research Database (Denmark)

    Eriksen, L; Tolstrup, J S; Larsen, Steen

    2014-01-01

    In 11 680 individuals (18-85 years) maximal oxygen consumption (VO2max) was estimated indirectly in a maximal cycle test using a prediction model developed in a young population (15-28 years). A subsample of 182 individuals (23-77 years) underwent 2 maximal cycle tests with VO2max estimated...... we suggest a new prediction model of VO2max. The maximal cycle test was highly repeatable....

  19. Maximal strength training improves cycling economy in competitive cyclists.

    Science.gov (United States)

    Sunde, Arnstein; Støren, Oyvind; Bjerkaas, Marius; Larsen, Morten H; Hoff, Jan; Helgerud, Jan

    2010-08-01

    The purpose of the present study was to investigate the effect of maximal strength training on cycling economy (CE) at 70% of maximal oxygen consumption (Vo2max), work efficiency in cycling at 70% Vo2max, and time to exhaustion at maximal aerobic power. Responses in 1 repetition maximum (1RM) and rate of force development (RFD) in half-squats, Vo2max, CE, work efficiency, and time to exhaustion at maximal aerobic power were examined. Sixteen competitive road cyclists (12 men and 4 women) were randomly assigned into either an intervention or a control group. Thirteen (10 men and 3 women) cyclists completed the study. The intervention group (7 men and 1 woman) performed half-squats, 4 sets of 4 repetitions maximum, 3 times per week for 8 weeks, as a supplement to their normal endurance training. The control group continued their normal endurance training during the same period. The intervention manifested significant (p < 0.05) improvements in 1RM (14.2%), RFD (16.7%), CE (4.8%), work efficiency (4.7%), and time to exhaustion at pre-intervention maximal aerobic power (17.2%). No changes were found in Vo2max or body weight. The control group exhibited an improvement in work efficiency (1.4%), but this improvement was significantly (p < 0.05) smaller than that in the intervention group. No changes from pre- to postvalues in any of the other parameters were apparent in the control group. In conclusion, maximal strength training for 8 weeks improved CE and efficiency and increased time to exhaustion at maximal aerobic power among competitive road cyclists, without change in maximal oxygen uptake, cadence, or body weight. Based on the results from the present study, we advise cyclists to include maximal strength training in their training programs.

  20. Seasonal variations in VO2max, O2-cost, O2-deficit, and performance in elite cross-country skiers.

    Science.gov (United States)

    Losnegard, Thomas; Myklebust, Håvard; Spencer, Matt; Hallén, Jostein

    2013-07-01

    Long-term effects of training are important information for athletes, coaches, and scientists when associating changes in physiological indices with changes in performance. Therefore, this study monitored changes in aerobic and anaerobic capacities and performance in a group of elite cross-country skiers during a full sport season. Thirteen men (age, 23 ± 2 years; height, 182 ± 6 cm; body mass, 76 ± 8 kg; V2 roller ski skating VO2max, 79.3 ± 4.4 ml·kg·min or 6.0 ± 0.5 L·min) were tested during the early, middle, and late preparation phase: June (T1), August (T2), and October (T3); during the competition phase: January/February (T4); and after early precompetition phase: June (T5). O2-cost during submaximal efforts, V[Combining Dot Above]O2peak, accumulated oxygen deficit (ΣO2-deficit), and performance during a 1,000-m test were determined in the V2 ski skating technique on a roller ski treadmill. Subjects performed their training on an individual basis, and detailed training logs were categorized into different intensity zones and exercise modes. Total training volume was highest during the summer months (early preseason) and decreased toward and through the winter season, whereas the volume of high-intensity training increased (all p testing sessions for 1,000 m time, O2-cost, and ΣO2-deficit (Cohen's d effect size; ES = 0.63-1.37, moderate to large, all p < 0.05). In general, the changes occurred between T1 and T3 with minor changes in the competitive season (T3 to T4). No significant changes were found in V[Combining Dot Above]O2peak across the year (ES = 0.17, trivial). In conclusion, the training performed by elite cross-country skiers induced no significant changes in V[Combining Dot Above]O2peak but improved performance, O2-cost, and ΣO2-deficit.

  1. Reproducibility of maximum aerobic power (VO2max among soccer players using a modified heck protocol Reprodutibilidade da potência aeróbia máxima (VO2max em jogadores de futebol utilizando o protocolo de heck modificado

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Santos-Silva

    2007-01-01

    Full Text Available OBJECTIVE: To determine the degree of reproducibility of maximum oxygen consumption (VO2max among soccer players, using a modified Heck protocol. METHODS: 2 evaluations with an interval of 15 days between them were performed on 11 male soccer players. All the players were at a high performance level; they were training for an average of 10 hours per week, totaling 5 times a week. When they were evaluated, they were in the middle of the competitive season, playing 1 match per week. The soccer players were evaluated on an ergometric treadmill with velocity increments of 1.2 km.h-1 every 2 minutes and a fixed inclination of 3% during the test. VO2max was measured directly using a breath-by-breath metabolic gas analyzer. RESULTS: The maximum running speed and VO2max attained in the 2 tests were, respectively: (15.6 ± 1.1 vs. 15.7 ± 1.2 km.h-1; [P = .78] and (54.5 ± 3.9 vs. 55.2 ± 4.4 ml.kg-1.min-1; [P = .88]. There was high and significant correlation of VO2max between the 2 tests with a 15-day interval between them [r = 0.97; P OBJETIVO: Determinar o grau de reprodutibilidade do consumo máximo de oxigênio (VO2max em jogadores de futebol utilizando o protocolo de Heck modificado. MÉTODOS: Foram avaliados por duas vezes, com intervalo de 15 dias entre os testes, 11 futebolistas masculinos. Todos eram de alto nível, treinavam em média 10 horas por semana subdivididos em treinamentos físicos, técnicos, táticos e jogos competitivos, totalizando cinco vezes por semana e na fase em que foram avaliados se encontravam em pleno período competitivo realizando um jogo por semana. Os futebolistas foram avaliados em esteira ergométrica (1,2 km.h-1 a cada dois minutos e inclinação fixa durante o teste em 3%. O VO2max foi medido diretamente utilizando analisador metabólico de análise de gases expirados respiração-a-respiração. RESULTADOS: A velocidade máxima de corrida e o VO2max atingido nos dois testes foram respectivamente: (15,6 ± 1

  2. CONSUMO MÁXIMO DE OXÍGENO (VO2max EN BOMBEROS: REVISIÓN SISTEMÁTICA DE ESTUDIOS

    Directory of Open Access Journals (Sweden)

    Jimmy Rojas Quirós

    2013-07-01

    Full Text Available Rojas, J.(2012.Maximun oxygen consumption (VO2max in fire fighters: a systematic review of studies. The fireman's profession is listed as a profession of risk, with high physical requirement;, in recent years the firefighter has acquired more powers itself out fires,including interventions in traffic accidents, hazardous materials incidents, rescues, forest fires, among others. The traditional image of the firefighter has given way to new professionals ready to face all kinds of disasters by the talk today offullfirefighter. The aimof this studywas to systematically reviewthe scientific evidence onthe level ofmaximun oxygen intake(VO2max that a firefightermust haveto fulfill theirdaily obligations. Weincludeda total of 19studies, publishedbetween 2002and2012, fromEBSCOhostdatabases, SpringerLink, SPORTDiscusandjournalsas Journalof SportsScience&Medicine, among others. We concludethisreview, based on the resultsof the studies, that different populationsoffire, haunt aVO2maxof34.80 to 58.21ml/kg/min, which varieswiththe initial conditionfirefightersstudies proposingdifferentauthors, in generalit is determined thata firefightermust haveVO2maxvaluesabove43 ml/kg/min, which is the minimumrecommended toat leasthave a goodaerobic capacitythat enablesfunction inits core functionsas a firefighter.ResumenConsumo máximo de oxígeno (VO2max en bomberos: revisión sistemática de estudios. El trabajo de bombero es catalogada como una profesión de riesgo, con alto requerimiento físico; en los últimos años el bombero ha adquirido más competencias que la propia de apagar incendios, entre ellas las intervenciones en accidentes de tránsito, incidentes con materiales peligrosos, rescates, fuegos forestales, entre otros. La imagen del bombero tradicional ha dado paso a nuevos profesionales preparados para afrontar todo tipo de desastres por lo que se habla en la actualidad del bombero completo. El objetivo de este estudio fue revisar sistemáticamente la

  3. Sport-specific fitness testing differentiates professional from amateur soccer players where VO2max and VO2 kinetics do not.

    Science.gov (United States)

    Wells, C M; Edwards, A M; Winter, E M; Fysh, M L; Drust, B

    2012-06-01

    The purpose of this study was to identify if sport-specific and cardiopulmonary exercise testing differentiated professional from amateur soccer players. Thirty six men comprising 18 professional (mean±s: age 23.2±2.4 years) and 18 amateur (mean±SD: age 21.1±1.6 years) soccer players participated and performed four tests on separate occasions: 1) a graded exercise test to determine VO2max; 2) four exercise transients from walking to 80%Δ for the determination of VO2 kinetics; 3) the Yo-Yo Intermittent Recovery Test level 2 (Yo-Yo IR2) and 4) a repeated sprint test (RST). The players did not differ in VO2max (professional 56.5±2.9 mL.kg-1.min-1; amateur 55.7±3.5 mL.kg-1.min-1: P=0.484) or VO2 kinetic fundamental measures (τ1 onset, professional 24.5±3.2 s; amateur 24.0±1.8 s: τ1 cessation, professional 28.7±2.8 s; amateur 29.3±3.5 s: P=0.923). However, the amateurs were outperformed in the Yo-Yo IR2 (Professional 966±153 m; Amateur 840±156 m) (P=0.034) and RST (best time, professional 6.46±0.27 s; amateur 6.84±0.24 s, P=0.012). Performance indices derived from field-based sport-specific performance tests identified significant differences between professional and amateur players (Ptests of VO2 kinetics nor VO2max differentiated between groups, suggesting laboratory tests of cardiorespiratory parameters are probably less consequential to soccer than sport-specific field-based observations.

  4. Determinación del Vo2max en un grupo de adultos que practican natación recreativa en la ciudad de Tres Arroyos

    OpenAIRE

    2015-01-01

    El presente trabajo se encuadra dentro de la realidad de un grupo de personas que practican Natación de forma recreativa en la ciudad de Tres Arroyos. El tema que rige la investigación de la tesis se basa en la determinación del Consumo máximo de oxígeno (Vo2 max) de los nadadores a través de pruebas indirectas1, test máximo incremental de Lavoie realizadas en la piscina. Además se tomaron otros test en donde las variables fueron tiempo y distancia a máxima intensidad, estos fu...

  5. Influência do estado nutricional e do VO2max nos níveis de adiponectina em homens acima de 35 anos

    Directory of Open Access Journals (Sweden)

    Eduardo Camillo Martinez

    2011-06-01

    Full Text Available FUNDAMENTO: A adiponectina é considerada importante fator na patogênese das doenças cardiovasculares e metabólicas, por suas propriedades antiaterogênicas e antiinflamatórias. Poucos estudos, entretanto, sugerem a existência de relação direta entre os níveis de adiponectina e os níveis de condicionamento cardiorrespiratório e atividade física. OBJETIVO: Verificar a influência do estado nutricional e do condicionamento cardiorrespiratório nos níveis plasmáticos de adiponectina em homens adultos. MÉTODOS: Foram avaliados 250 sujeitos, homens, todos militares da ativa do Exército Brasileiro (42,6 ± 4,8 anos. Foram mensurados os níveis plasmáticos de adiponectina, massa corporal, estatura, circunferência da cintura (CC, percentual de gordura por pesagem hidrostática e VO2max por ergoespirometria. Um questionário foi utilizado para obter as características do treinamento físico realizado pelos sujeitos. RESULTADOS: Na amostra, 121 (48% sujeitos apresentaram sobrepeso e 36 (14% eram obesos. Ainda, 66 sujeitos (27% apresentaram percentual de gordura maior que 25% e 26.7% apresentaram CC > 94 cm. Sujeitos com sobrepeso e obesidade apresentaram valores significativamente menores de adiponectina em relação aqueles com estado nutricional normal. Sujeitos no mais alto tercil de VO2max apresentaram níveis de adiponectina mais altos que os demais. Os níveis de adiponectina estiveram positivamente correlacionados com o tempo total de treinamento físico semanal e com o VO2max e inversamente correlacionados com os valores de massa corporal, IMC e CC. A correlação dos níveis de adiponectina e do VO2max não permaneceu significante após controlada pelo IMC e CC. CONCLUSÃO: Sujeitos com melhor condicionamento cardiorrespiratório e com estado nutricional normal parecem apresentar níveis mais saudáveis de adiponectina.

  6. The Effects of Ingestion of Sugarcane Juice and Commercial Sports Drinks on Cycling Performance of Athletes in Comparison to Plain Water

    OpenAIRE

    Kalpana, Kommi; Lal, Priti Rishi; Kusuma, Doddipalli Lakshmi; Khanna, Gulshan Lal

    2013-01-01

    Purpose Sugarcane juice (ScJ) is a natural drink popular in most tropical Asian regions. However, research on its effect in enhancing sports performance is limited. The present investigation was to study the effect of sugarcane juice on exercise metabolism and sport performance of athletes in comparison to a commercially available sports drinks. Methods Fifteen male athletes (18-25 yrs) were asked to cycle until volitional exhaustion at 70% VO2 max on three different trials viz. plain water (...

  7. Sex-Specific Equations to Estimate Maximum Oxygen Uptake in Cycle Ergometry

    OpenAIRE

    Christina G. de Souza e Silva; Araújo,Claudio Gil S.

    2015-01-01

    Abstract Background: Aerobic fitness, assessed by measuring VO2max in maximum cardiopulmonary exercise testing (CPX) or by estimating VO2max through the use of equations in exercise testing, is a predictor of mortality. However, the error resulting from this estimate in a given individual can be high, affecting clinical decisions. Objective: To determine the error of estimate of VO2max in cycle ergometry in a population attending clinical exercise testing laboratories, and to propose sex-spec...

  8. Supervised physical exercise improves VO2max, quality of life, and health in early stage breast cancer patients: a randomized controlled trial.

    Science.gov (United States)

    Casla, Soraya; López-Tarruella, Sara; Jerez, Yolanda; Marquez-Rodas, Iván; Galvão, Daniel A; Newton, Robert U; Cubedo, Ricardo; Calvo, Isabel; Sampedro, Javier; Barakat, Rubén; Martín, Miguel

    2015-09-01

    Breast cancer patients suffer impairment in cardiorespiratory fitness after treatment for primary disease, affecting patients' health and survival. The aim of this study was to evaluate the ability of a pragmatic exercise intervention to improve cardiorespiratory fitness of breast cancer patients after primary treatment. Between February 2013 and December 2014, 94 women with early stage (I-III) breast cancer, 1-36 months post-chemotherapy, and radiotherapy were randomly assigned to an intervention program (EX) combining supervised aerobic and resistance exercise (n = 44) or usual care (CON) (n = 45) for 12 weeks. Primary study endpoint was VO2max. Secondary endpoints were muscle strength, shoulder range of motion, body composition, and quality of life (QoL). Assessments were undertaken at baseline, 12-week, and 6-month follow-ups. Eighty-nine patients aged 29-69 years were assessed at baseline and 12 weeks. The EX group showed significant improvements in VO2max, muscle strength, percent fat, and lean mass (p ≤ 0.001 in all cases) and QoL compared with usual care (CON). Apart from body composition, improvements were maintained for the EX at 6-month follow-up. There were no adverse events during the testing or exercise intervention program. A combined exercise intervention produced considerable improvement in cardiorespiratory fitness, physical function, and quality of life in breast cancer patients previously treated with chemotherapy and radiation therapy. Importantly, most of these benefits were maintained 6 months after ceasing the supervised exercise intervention.

  9. The influence of evaluation protocol on time spent exercising at a high level of oxygen uptake during continuous cycling

    OpenAIRE

    Merry, KL; Glaister, Mark; Howatson, Glyn; van Someren, Ken A.

    2015-01-01

    AIM: This study evaluated the effects of protocol variation on the time spent exercising at ≥95% .VO2max during cycle ergometer trials performed at the exercise intensity associated with .VO2max (i .VO2max).\\ud METHODS: Nine male triathletes (age: 32±10 years; body mass: 73.3±6.1 kg; stature: 1.79±0.07 m; .VO2max: 3.58±0.45 L.min-1) performed four exercise tests. During tests 1 and 2, participants performed a maximal incremental cycle ergometer test using different stage durations (1 min and ...

  10. Regular dark chocolate consumption's reduction of oxidative stress and increase of free-fatty-acid mobilization in response to prolonged cycling.

    Science.gov (United States)

    Allgrove, Judith; Farrell, Emily; Gleeson, Michael; Williamson, Gary; Cooper, Karen

    2011-04-01

    This study investigated the effects of regular consumption of dark chocolate (DC), rich in cocoa polyphenols, on plasma metabolites, hormones, and markers of oxidative stress after prolonged exhaustive exercise. Twenty active men cycled at 60% maximal oxygen uptake (VO2max) for 1.5 hr, with the intensity increased to 90% VO2max for a 30-s period every 10 min, followed by a ride to exhaustion at 90% VO2max. In the 2 wk before exercise participants consumed 40 g of DC or an isocarbohydrate-fat control cocoa liquor-free chocolate (CON) twice daily and once 2 hr before exercise in a randomized, counterbalanced, crossover design. Venous blood samples were taken immediately before exercise, postexercise (fixed duration), postexhaustion, and after 1 hr of recovery. F2-isoprostanes were significantly lower (post hoc tests: p < .001) at exhaustion and after 1 hr of recovery with DC. Oxidized low-density lipoproteins were significantly lower with DC (p < .001) both before and after exercise and at exhaustion. DC was also associated with ~21% greater rises in free fatty acids during exercise (main effect: p < .05). Changes in circulating glucose, insulin, glucagon, cortisol, and interleukin (IL)-6, IL-10, and IL-1ra were unaffected by treatment. Time to exhaustion at 90% VO2max was not significantly different between trials (398 ± 204 and 374 ± 194 s for DC and CON, respectively). These results suggest that regular DC intake is associated with reduced oxidative-stress markers and increased mobilization of free fatty acids after exercise but has no observed effect on exercise performance.

  11. The effects of modified exponential tapering technique on perceived exertion, heart rate, time trial performance, VO2max and power output among highly trained junior cyclists.

    Science.gov (United States)

    Ishak, Asmadi; Hashim, Hairul A; Krasilshchikov, Oleksandr

    2016-09-01

    The present study investigated the effects of a 2-week modified exponential taper on physiological adaptation and time trial performance among junior cyclists. Participants (N.=27) with the mean age of 16.95±0.8 years, height of 165.6±6.1 cm and weight of 54.19±8.1 kg were matched into either modified exponential taper (N.=7), normal exponential taper (N.=7), or control (N.=7) groups using their initial VO2max values. Both experimental groups followed a 12-week progressive endurance training program and subsequently, a 2-week tapering phase. A simulated 20-km time trial performance along with VO2max, power output, heart rate and rating of perceived exertion were measured at baseline, pre and post-taper. One way ANOVA was used to analyze the difference between groups before the start of the intervention while mixed factorial ANOVA was used to analyze the difference between groups across measurement sessions. When homogeneity assumption was violated, the Greenhouse-Geisser Value was used for the corrected values of the degrees of freedom for the within subject factor the analysis. Significant interactions between experimental groups and testing sessions were found in VO2max (F=6.67, df=4, P<0.05), power output (F=5.02, df=4, P<0.05), heart rate (F=10.87, df=2.51, P<0.05) rating of perceived exertion (F=13.04, df=4, P<0.05) and 20KM time trial (F=4.64, df=2.63, P<0.05). Post-hoc analysis revealed that both types of taper exhibited positive effects compared to the non-taper condition in the measured performance markers at post-taper while no different were found between the two taper groups. It was concluded that both taper protocols successfully inducing physiological adaptations among the junior cyclists by reducing the volume and maintaining the intensity of training.

  12. The contribution of preintervention blood pressure, VO2max, BMI, autonomic function and gender to exercise-induced changes in heart rate variability.

    Science.gov (United States)

    Grant, Catharina C; Janse van Rensburg, Dina C

    2013-06-01

    The quantification of heart rate variability (HRV) is a tool to assess the interaction between exercise and autonomic control, as well as the pathophysiology of diseases affecting autonomic function. Little is known about the influence of genetically influenced physiology on exercise-induced changes in autonomic cardiac regulation. It was theorised that preintervention values for blood pressure, VO2max, body mass index (BMI), autonomic function and gender contribute significantly to the exercise-induced changes in HRV. A 12-week, medium-to-high intensity exercise intervention was completed by 183 volunteers (18-22 years). Data were sampled at baseline and after 12 weeks. Standard time domain, frequency domain and Poincaré HRV quantification techniques were implemented. Regression analysis was performed to determine the influences of the predictors (baseline values for low frequency  (LF), high frequency (HF), BMI, VO2max, gender, blood pressure) on the exercise-induced response of the dependent variables (changes in HRV-indicator values). Parameters found to be significant (pexercise-induced changes were LF, HF and systolic blood pressure in, respectively, 10, 5 and 2 of the 12 regressions performed. The results indicated that the independent variables contribute between 12.83% and 29.82%, depending on the specific HRV indicator, to the exercise-induced changes in the autonomic nervous system. Preintervention autonomic status, as represented specifically by LF, is the most important determinant of cardiac autonomic response to an exercise intervention in a healthy study population. Baseline autonomic function could thus be a significant confounder in the outcome of exercise study results.

  13. A acurácia da determinação do VO2max e do limiar anaeróbio La exactitud en la determinacion del VO2máx y del umbral anaerobico Accuracy of VO2max and anaerobic threshold determination

    Directory of Open Access Journals (Sweden)

    Paulo Cesar N Granja Filho

    2005-06-01

    Full Text Available São raros estudos que tratam da acurácia de parâmetros de trocas gasosas durante o esforço, com a população brasileira. OBJETIVO: Determinar a confiabilidade do consumo máximo de oxigênio (VO2max e do limiar anaeróbio (LAn, assim como, a objetividade do segundo (LAn em adultos jovens saudáveis. MÉTODOS: Foram aplicados dois testes de esforço máximo, a partir dos quais dois observadores independentes determinaram o LAn através do método de inspeção visual. Os dados foram tratados por meio da análise de regressão, coeficiente de correlação intraclasse (CCI, ANOVA com dois fatores com teste post hoc de Tukey e teste t pareado para alfa Son raros los estudios que tratan de la exactitud de los parámetros de cambios gaseosos durante el esfuerzo con la población brasileña. OBJETIVO: Determinar la confiabilidad del consumo máximo de oxigeno (VO2max y del umbral anaeróbico (LAn, así como la objetividad del segundo, (LAn en adultos jovenes saludables. MÉTODOS: Fueron aplicados dos tests de esfuerzo máximo, a partir de los cuales dos observadores independientes determinaron el LAn a través del método de inspección visual. Los datos fueron tratados por medio del análisis de regresión, coeficiente de relación intraclase (CCI, ANOVA com dos factores con test post hoc de Tukey y el test t apareado para alfa Studies on the accuracy of the gas exchange and ventilation parameters during exertion involving the Brazilian population are scarce in literature. OBEJCTIVE: To determine the reliability of the maximal oxygen intake (VO2max and anaerobic threshold (AnT, as well as the objectivity of the AnT determination in Brazilian healthy youth adults. METHODS: Two tests of maximal exertion were applied. Two independent observers applied the visual inspection method for the AnT determination. The data were compared by means of the regression analysis, intraclass correlation coefficient (ICC, two-way ANOVA and the paired t-test for an

  14. Intake of Protein Plus Carbohydrate during the First Two Hours after Exhaustive Cycling Improves Performance the following Day.

    Science.gov (United States)

    Rustad, Per I; Sailer, Manuela; Cumming, Kristoffer T; Jeppesen, Per B; Kolnes, Kristoffer J; Sollie, Ove; Franch, Jesper; Ivy, John L; Daniel, Hannelore; Jensen, Jørgen

    2016-01-01

    Intake of protein immediately after exercise stimulates protein synthesis but improved recovery of performance is not consistently observed. The primary aim of the present study was to compare performance 18 h after exhaustive cycling in a randomized diet-controlled study (175 kJ·kg(-1) during 18 h) when subjects were supplemented with protein plus carbohydrate or carbohydrate only in a 2-h window starting immediately after exhaustive cycling. The second aim was to investigate the effect of no nutrition during the first 2 h and low total energy intake (113 kJ·kg(-1) during 18 h) on performance when protein intake was similar. Eight endurance-trained subjects cycled at 237±6 Watt (~72% VO2max) until exhaustion (TTE) on three occasions, and supplemented with 1.2 g carbohydrate·kg(-1)·h(-1) (CHO), 0.8 g carbohydrate + 0.4 g protein·kg(-1)·h(-1) (CHO+PRO) or placebo without energy (PLA). Intake of CHO+PROT increased plasma glucose, insulin, and branch chained amino acids, whereas CHO only increased glucose and insulin. Eighteen hours later, subjects performed another TTE at 237±6 Watt. TTE was increased after intake of CHO+PROT compared to CHO (63.5±4.4 vs 49.8±5.4 min; pintake of CHO+PROT compared to an isocaloric amount of carbohydrate during the first 2 h post exercise. Intake of a similar amount of protein but less carbohydrate during the 18 h recovery period reduced performance.

  15. Difference in Physiological Components of VO2 Max During Incremental and Constant Exercise Protocols for the Cardiopulmonary Exercise Test.

    Science.gov (United States)

    Yamamoto, Junshiro; Harada, Tetsuya; Okada, Akinori; Maemura, Yuko; Yamamoto, Misaki; Tabira, Kazuyuki

    2014-08-01

    [Purpose] VO2 is expressed as the product of cardiac output and O2 extraction by the Fick equation. During the incremental exercise test and constant high-intensity exercise test, VO2 results in the attainment of maximal O2 uptake at exhaustion. However, the differences in the physiological components, cardiac output and muscle O2 extraction, have not been fully elucidated. We tested the hypothesis that constant exercise would result in higher O2 extraction than incremental exercise at exhaustion. [Subjects] Twenty-five subjects performed incremental exercise and constant exercise at 80% of their peak work rate. [Methods] Ventilatory, cardiovascular, and muscle oxygenation responses were measured using a gas analyzer, Finapres, and near-infrared spectroscopy, respectively. [Results] VO2 was not significantly different between the incremental exercise and constant exercise. However, cardiac output and muscle O2 saturation were significantly lower for the constant exercise than the incremental exercise at the end of exercise. [Conclusion] These findings indicate that if both tests produce a similar VO2 value, the VO2 in incremental exercise would have a higher ratio of cardiac output than constant exercise, and VO2 in constant exercise would have a higher ratio of O2 extraction than incremental exercise at the end of exercise.

  16. The effect of acute L-Carnitine supplementation on the blood lactate, glucose, VO2max and power in trained men: a brief report

    Directory of Open Access Journals (Sweden)

    Arazi H

    2013-04-01

    Full Text Available Background: Probably L-Carnitine can induce increasing of Pyruvate dehydrogenase activity, decreasing of lactic acid production and performance improvements due to the reinforcement of long chain fatty acid oxidation and stabilize of Coenzyme A (CoASH to free Coenzyme A (COA. Based on this, the aim of this study was to investigate the effect of acute L-Carnitine supplementation on blood lactate, glucose, VO2max and anaerobic power in trained men.Methods: Sixteen trained men (aged 19-23 volunteers from University of Guilan, facul-ty of Physical Education and Sport Sciences participated as subjects in this investiga-tion. Subjects divided to aerobic (A and anaerobic (An group randomly. In a double blind design, subjects participated in two separated tests by one week. Subjects ingested 3 grams of L-Carnitine supplementation or placebo (maltodextrin 90 minute before aerobic and anaerobic exercise. For aerobic activity used shuttle run 20 meter and for anaerobic activity used RAST test. Blood samples were collected 5 minute prior at rest and 4 minute post tests. Participants were asked in the morning to obtain fasting blood samples and perform tests. A t-test was used to detect differences between supplementa-tion and placebo groups in each exercise.Results: L-Carnitine group ((A 141.25±20.62 and (An 145.38±55.47 significantly had lower lactate concentration than placebo ((A 151.00±20.85 and (An 152.50±28.59 after tests (P≤0.05. L-Carnitine group ((A 136.00±19.74 and (An 115.50±13.64 had significa-ntly higher blood glucose compared to placebo ((A 121.62±15.65 and (An 110.12±12.63 too (P≤0.05. Also, VO2max, mean and maximum anaerobic power in L-Carnitine group were significantly more than ones in placebo (P<0.05.Conclusion: These findings indicate that acute oral supplementation of L-Carnitine can induce fatigue decreasing and improvement of aerobic and anaerobic performance.

  17. Plasma volume expansion does not increase maximal cardiac output or VO2 max in lowlanders acclimatized to altitude

    DEFF Research Database (Denmark)

    Calbet, José A L; Rådegran, Göran; Boushel, Robert Christopher

    2004-01-01

    With altitude acclimatization, blood hemoglobin concentration increases while plasma volume (PV) and maximal cardiac output (Qmax) decrease. This investigation aimed to determine whether reduction of Qmax at altitude is due to low circulating blood volume (BV). Eight Danish lowlanders (3 females, 5...... males: age 24.0 +/- 0.6 yr; mean +/- SE) performed submaximal and maximal exercise on a cycle ergometer after 9 wk at 5,260 m altitude (Mt. Chacaltaya, Bolivia). This was done first with BV resulting from acclimatization (BV = 5.40 +/- 0.39 liters) and again 2-4 days later, 1 h after PV expansion with 1...... level Qmax and exercise capacity were restored with hyperoxia at altitude independently of BV. Low BV is not a primary cause for reduction of Qmax at altitude when acclimatized. Furthermore, hemodilution caused by PV expansion at altitude is compensated for by increased systemic O2 extraction...

  18. Plasma volume expansion does not increase maximal cardiac output or VO2 max in lowlanders acclimatized to altitude.

    Science.gov (United States)

    Calbet, José A L; Rådegran, Göran; Boushel, Robert; Søndergaard, Hans; Saltin, Bengt; Wagner, Peter D

    2004-09-01

    With altitude acclimatization, blood hemoglobin concentration increases while plasma volume (PV) and maximal cardiac output (Qmax) decrease. This investigation aimed to determine whether reduction of Qmax at altitude is due to low circulating blood volume (BV). Eight Danish lowlanders (3 females, 5 males: age 24.0 +/- 0.6 yr; mean +/- SE) performed submaximal and maximal exercise on a cycle ergometer after 9 wk at 5,260 m altitude (Mt. Chacaltaya, Bolivia). This was done first with BV resulting from acclimatization (BV = 5.40 +/- 0.39 liters) and again 2-4 days later, 1 h after PV expansion with 1 liter of 6% dextran 70 (BV = 6.32 +/- 0.34 liters). PV expansion had no effect on Qmax, maximal O2 consumption (VO2), and exercise capacity. Despite maximal systemic O2 transport being reduced 19% due to hemodilution after PV expansion, whole body VO2 was maintained by greater systemic O2 extraction (P VO2 during exercise regardless of PV. Pulmonary ventilation, gas exchange, and acid-base balance were essentially unaffected by PV expansion. Sea level Qmax and exercise capacity were restored with hyperoxia at altitude independently of BV. Low BV is not a primary cause for reduction of Qmax at altitude when acclimatized. Furthermore, hemodilution caused by PV expansion at altitude is compensated for by increased systemic O2 extraction with similar peak muscular O2 delivery, such that maximal exercise capacity is unaffected.

  19. Effect of exhaustive exercise on the angular pedaling pattern: A preliminary study

    Directory of Open Access Journals (Sweden)

    Matheus Joner Wiest

    2009-09-01

    Full Text Available Considering biomechanical aspects such as kinematics, fatigue can be characterized as a loss of efficiency in maintaining a movement pattern, such as pedaling technique, during exercise. The objective of this preliminary study was to investigate the effects of 1-h exhaustive cycling exercise at intensity of 80% VO2max on pedaling technique. The pedaling technique was evaluated in four skilled mountain-bike cyclists by 2D kinematics. The main hypothesis of this study was that angular changes in response to fatigue would occur mainly in the ankle joint. After achievement of maximal oxygen uptake (VO2max, the cyclists were submitted to a submaximal protocol at intensity corresponding to 80% VO2max for 1 h. The cyclists were filmed throughout 10 complete consecutive crank cycles at intervals of 10 min. Images were acquired from the right lower limb and the hip, knee and ankle joint angles were measured after kinematic processing. The Shapiro-Wilk test, ANOVA and post-hoc Tukey HSD test were used for statistical analysis, with the level of significance set at 0.05. Statistical analysis showed a significant difference only for ankle kinematics after 40 min of exercise, with an increase in the range of motion from 20° at the beginning of exercise to 35° at the end of exercise. This result confirms the hypothesis proposed and suggests that only the ankle joint was affected by the exercise. The characteristics of ankle movement suggest that this joint plays a compensatory role in an attempt to maintain the pedaling technique and to sustain the exercise workload.

  20. 初中生台阶试验、800米跑与 VO2 max 的相关性研究%Relevant Studies on Step Tests for Junior Middle SChool Students., Long-distance Race of 800 Meters and VO2 max

    Institute of Scientific and Technical Information of China (English)

    彭丽英

    2014-01-01

    The study tests the aerobic capabilities of junior middle school students by means of literature statistics , experiment and mathematical statistics , aimming at studying the appropriate way of testing the aerobic capabilities of junior middle school students, which provides data supports for further testing the physique qualities of middle school students .The research findings suggest that the relevance of step tests for junior middle school students and the relative value of VO 2 max are respectively as r =0. 12,r=0.08, P>0.05;The relevance between Long -distance race of 800 meters and VO2 max is repectively as r=-0.19,r=-0.20, p>0.05.The two testing ways has little relations with VO 2 max.The research findings suggest that there are some defi-ciencies on testing the aerobic capabilities of junior middle school students by means of step tests and Long -distance race of 800 meters which couldn ’ t efficiently reflect cardiovascular functions of middle school students .It is inapproriate to test the aerobic endurance capabilities in high school graduation exams by means of this method .%采用文献资料法、实验法、数理统计法对初中生有氧运动能力进行测试,其目的是研究适合测试初中生有氧运动能力的方法。为今后中学生体质测试方法的完善提供数据支撑。其研究结果:初中男、女生台阶试验与最大摄氧量( VO2 max)相对值的相关性分别为r=0.12,r=0.08,p值均大于0.05;800米跑与VO2 max相对值的相关性分别为r=-0.19,r=-0.20,p值均大于0.05。两种方法均与VO2 max呈微弱关系。结果表明:台阶试验、800米跑用于评定初中生有氧耐力存在一定的问题,此两种方法不能有效的反映中学生的心血管机能水平。中考中利用此方法来评定有氧耐力水平欠妥当。

  1. Health-Related Physical Fitness in Healthy Untrained Men: Effects on VO2max, Jump Performance and Flexibility of Soccer and Moderate-Intensity Continuous Running.

    Directory of Open Access Journals (Sweden)

    Zoran Milanović

    Full Text Available The purpose of this study was to determine the effects of recreational soccer (SOC compared to moderate-intensity continuous running (RUN on all health-related physical fitness components in healthy untrained men. Sixty-nine participants were recruited and randomly assigned to one of three groups, of which sixty-four completed the study: a soccer training group (SOC; n = 20, 34±4 (means±SD years, 78.1±8.3 kg, 179±4 cm; a running group (RUN; n = 21, 32±4 years, 78.0±5.5 kg, 179±7 cm; or a passive control group (CON; n = 23, 30±3 years, 76.6±12.0 kg, 178±8 cm. The training intervention lasted 12 weeks and consisted of three 60-min sessions per week. All participants were tested for each of the following physical fitness components: maximal aerobic power, minute ventilation, maximal heart rate, squat jump (SJ, countermovement jump with arm swing (CMJ, sit-and-reach flexibility, and body composition. Over the 12 weeks, VO2max relative to body weight increased more (p<0.05 in SOC (24.2%, ES = 1.20 and RUN (21.5%, ES = 1.17 than in CON (-5.0%, ES = -0.24, partly due to large changes in body mass (-5.9, -5.7 and +2.6 kg, p<0.05 for SOC, RUN and CON, respectively. Over the 12 weeks, SJ and CMJ performance increased more (p<0.05 in SOC (14.8 and 12.1%, ES = 1.08 and 0.81 than in RUN (3.3 and 3.0%, ES = 0.23 and 0.19 and CON (0.3 and 0.2%, while flexibility also increased more (p<0.05 in SOC (94%, ES = 0.97 than in RUN and CON (0-2%. In conclusion, untrained men displayed marked improvements in maximal aerobic power after 12 weeks of soccer training and moderate-intensity running, partly due to large decreases in body mass. Additionally soccer training induced pronounced positive effects on jump performance and flexibility, making soccer an effective broad-spectrum fitness training intervention.

  2. A systematic review and meta-analysis comparing cardiopulmonary exercise test values obtained from the arm cycle and the leg cycle respectively in healthy adults

    DEFF Research Database (Denmark)

    Larsen, Rasmus Tolstrup; Christensen, Jan; Tang, Lars Hermann

    2016-01-01

    INTRODUCTION: The cardiopulmonary exercise test (CPET) assesses maximal oxygen uptake (VO2max) and is commonly performed on a leg cycle ergometer (LC). However, some individuals would rather perform the CPET on an arm cycle ergometer (AC). OBJECTIVE: The objectives of this study were to undertake...... a systematic review and meta-analysis of the difference in VO2max achieved by AC compared to LC in healthy adults and to explore factors that may be predictive of this difference. METHODS: MEDLINE, EMBASE, CINAHL, and PEDro were searched in April 2015. The differences in VO2max (ACLCdiff) were pooled across...

  3. In Healthy Young Men, a Short Exhaustive Exercise Alters the Oxidative Stress Only Slightly, Independent of the Actual Fitness.

    Science.gov (United States)

    Finkler, Maya; Hochman, Ayala; Pinchuk, Ilya; Lichtenberg, Dov

    2016-01-01

    The aim of the present study was to evaluate the apparent disagreement regarding the effect of a typical cycling progressive exercise, commonly used to assess VO2max, on the kinetics of ex vivo copper induced peroxidation of serum lipids. Thirty-two (32) healthy young men, aged 24-30 years, who do not smoke and do not take any food supplements, participated in the study. Blood was withdrawn from each participant at three time points (before the exercise and 5 minutes and one hour after exercise). Copper induced peroxidation of sera made of the blood samples was monitored by spectrophotometry. For comparison, we also assayed TBARS concentration and the activity of oxidation-related enzymes. The physical exercise resulted in a slight and reversible increase of TBARS and slight changes in the activities of the studied antioxidant enzymes and the lag preceding peroxidation did not change substantially. Most altered parameters returned to baseline level one hour after exercise. Notably, the exercise-induced changes in OS did not correlate with the physical fitness of the subjects, as evaluated in this study (VO2max = 30-60 mL/min/kg). We conclude that in healthy young fit men a short exhaustive exercise alters only slightly the OS, independent of the actual physical fitness.

  4. Acute Effect of One Incremental Exhausting Cycling Session with Hand on the Response of T and NK Cells of Immune System in Student Athletes

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    A Habibi

    2010-11-01

    Full Text Available Introduction: Various sorts of physical activites cause various changes in body immune system. The purpose of this study was to examine the acute effect of one incremental exhausting cycling session with hand on the response of T and NK cells of immune system of male physical education students. Methods: In this study, twenty male subjects with mean age of 22.4±1.8(SD years, mean Vo2 max 41.7±7.1(SD ml/kg/min and mean BMI 23±1.87(SD kg/m2 were divided randomly into control(n=10 and experimental group(n=10. The subjects of experimental group performed Sawaka. Protocol, whereas the subjects of control group did not participate in any exercise activity. Blood samples were taken from brachial vein of control and experimental subjects during pre-test, post-test and two hours after the end of exercise. For analysis of statistical data, t-independent and t-correlated tests ( =0.05 significant were used. Results: Immediately after training, the percentage of CD8 (T and CD16.56 (NK cells increased significantly (P≤0.005, P≤0.001. On the other hand, the ratio of CD4/CD8 cells and the percentage of CD4 (T cells showed significant decrease (P≤0.002, P≤0.001. In addition, the percentage of CD56 and CD16 (NK cells did not change significantly. It is worth mentioning that these changes after two hours returned to the normal state at the end of the sport test (P≤0.251, P≤0.229. Conclusion: One acute training session with hand causes both increase and decrease in T and NK cells of immune system function. But, these changes are temporary and return back to normal levels within a few hours.

  5. In healthy elderly postmenopausal women variations in BMD and BMC at various skeletal sites are associated with differences in weight and lean body mass rather than by variations in habitual physical activity, strength or VO2max.

    Science.gov (United States)

    Schöffl, I; Kemmler, W; Kladny, B; Vonstengel, S; Kalender, W A; Engelke, K

    2008-01-01

    The objective of this study was an integrated cross-sectional investigation for answering the question whether differences in bone mineral density in elderly postmenopausal women are associated with differences in habitual physical activity and unspecific exercise levels. Two hundred and ninety nine elderly women (69-/+3 years), without diseases or medication affecting bone metabolism were investigated. The influence of weight, body composition and physical activity on BMD was measured at multiple sites using different techniques (DXA, QCT, and QUS). Physical activity and exercise level were assessed by questionnaire, maximum strength of the legs and aerobic capacity. Variations in physical activity or habitual exercise had no effect on bone. The only significant univariate relation between strength/VO(2)max and BMD/BMC that remained after adjusting for confounding variables was between arm BMD (DXA) and hand-grip strength. The most important variable for explaining BMD was weight and for cortical BMC of the femur (QCT) lean body mass. Weight and lean body mass emerge as predominant predictors of BMD in normal elderly women, whereas the isolated effect of habitual physical activity, unspecific exercise participation, and muscle strength on bone parameters is negligible. Thus, an increase in the amount of habitual physical activity will probably have no beneficial impact on bone.

  6. The effects of prior cycling and a successive run on respiratory muscle performance in triathletes.

    Science.gov (United States)

    Boussana, A; Galy, O; Hue, O; Matecki, S; Varray, A; Ramonatxo, M; Le Gallais, D

    2003-01-01

    The aim of the present study was to compare the effects of prior cycling and a successive run on respiratory muscle performance during a cycle-run succession as performed in the triathlon. We hypothesized that despite the moderate intensity of exercise and the absence of exhaustion, the crouched cycling position would induce a decrease in respiratory muscle performance that would be reversed by the successive vertical run position. Ten male triathletes (22.6 +/- 1.1 yr) performed a four-trial protocol: (1) an incremental cycle test to assess maximal oxygen uptake (VO2max), (2) 20 min of cycling (C), (3) 20 min of running (R), and (4) 20 min of cycling followed by 20 min of running (C-R). Trials 2, 3 and 4 were performed at the same metabolic intensity, i. e., 75 % of VO2max. Respiratory muscle force was assessed by measuring maximal expiratory (P(Emax)) and inspiratory (P(Imax)) pressures from the functional residual capacity (FRC) before and 10 min after C, R, and C-R. Respiratory muscle endurance was assessed one day before and 30 min after C, R, and C-R, by measuring the time limit (T(lim)), which corresponds to the length of time a respiratory load can be sustained before the process of fatigue develops sufficiently to cause task failure. The results showed a similar significant decrease in P(Imax) (132.4 +/- 4.9 versus 125.7 +/- 5.6 cm H2O, p 0.05). We concluded that moderate intensity exercise not performed to exhaustion induced a decrease in respiratory muscle performance. Moreover, the respiratory muscle fatigue induced by prior cycling was maintained, and neither reversed nor worsened, by the successive run.

  7. Sex-Specific Equations to Estimate Maximum Oxygen Uptake in Cycle Ergometry.

    Science.gov (United States)

    Souza e Silva, Christina G de; Araújo, Claudio Gil S

    2015-10-01

    Aerobic fitness, assessed by measuring VO2max in maximum cardiopulmonary exercise testing (CPX) or by estimating VO2max through the use of equations in exercise testing, is a predictor of mortality. However, the error resulting from this estimate in a given individual can be high, affecting clinical decisions. To determine the error of estimate of VO2max in cycle ergometry in a population attending clinical exercise testing laboratories, and to propose sex-specific equations to minimize that error. This study assessed 1715 adults (18 to 91 years, 68% men) undertaking maximum CPX in a lower limbs cycle ergometer (LLCE) with ramp protocol. The percentage error (E%) between measured VO2max and that estimated from the modified ACSM equation (Lang et al. MSSE, 1992) was calculated. Then, estimation equations were developed: 1) for all the population tested (C-GENERAL); and 2) separately by sex (C-MEN and C-WOMEN). Measured VO2max was higher in men than in WOMEN: -29.4 ± 10.5 and 24.2 ± 9.2 mL.(kg.min)-1 (p VO2max [in mL.(kg.min)-1] were: C-GENERAL = [final workload (W)/body weight (kg)] x 10.483 + 7; C-MEN = [final workload (W)/body weight (kg)] x 10.791 + 7; and C-WOMEN = [final workload (W)/body weight (kg)] x 9.820 + 7. The E% for MEN was: -3.4 ± 13.4% (modified ACSM); 1.2 ± 13.2% (C-GENERAL); and -0.9 ± 13.4% (C-MEN) (p VO2max by use of sex-specific equations was reduced, but not eliminated, in exercise tests on LLCE.

  8. One-legged endurance training: leg blood flow and oxygen extraction during cycling exercise

    DEFF Research Database (Denmark)

    Rud, B; Foss, O; Krustrup, Peter

    2012-01-01

    Aim: As a consequence of enhanced local vascular conductance, perfusion of muscles increases with exercise intensity to suffice the oxygen demand. However, when maximal oxygen uptake (VO(2) max) and cardiac output are approached, the increase in conductance is blunted. Endurance training increases...... muscle metabolic capacity, but to what extent that affects the regulation of muscle vascular conductance during exercise is unknown. Methods: Seven weeks of one-legged endurance training was carried out by twelve subjects. Pulmonary VO(2) during cycling and one-legged cycling was tested before and after...... training, while VO(2) of the trained leg (TL) and control leg (CL) during cycling was determined after training. Results: VO(2) max for cycling was unaffected by training, although one-legged VO(2) max became 6.7 (2.3)% (mean ± SE) larger with TL than with CL. Also TL citrate synthase activity was higher...

  9. Relationship between reduced lower abdominal blood flows and heart rate in recovery following cycling exercise.

    Science.gov (United States)

    Osada, T; Iwane, H; Katsumura, T; Murase, N; Higuchi, H; Sakamoto, A; Hamaoka, T; Shimomitsu, T

    2012-03-01

    To examine the blood flow (BF) response in the lower abdomen (LAB) in recovery following upright cycling exercise at three levels of relative maximum pulmonary oxygen consumption (VO(2max)) and the relationship of BF(LAB) to heart rate (HR) and target intensity. For 11 healthy subjects, BF (Doppler ultrasound) in the upper abdominal aorta (Ao) above the coeliac trunk and in the right femoral artery (RFA) was measured repeatedly for 720 s after the end of cycling exercises at target intensities of 30%, 50% and 85% VO(2max), respectively. Blood flow in the lower abdomen (BF(LAB)) can be measured by subtracting bilateral BF(FAs) (≈twofolds of BF(RFA)) from BF(Ao). Change in BF(LAB) (or BF(LAB) volume) at any point was evaluated by difference between change in BF(Ao) and in BF(FAs). Heart rate and blood pressure were also measured. At 85% VO(2max), significant reduction in BF(LAB) by approx. 89% was shown at 90 s and remained until 360 s. At 50% VO(2max), reduction in BF(LAB) by approx. 33% was found at 90 s although it returned to pre-exercise value at 120 s. On the contrary at 30% VO(2max), BF(LAB) showed a light increase (exercise intensities. © 2011 The Authors. Acta Physiologica © 2011 Scandinavian Physiological Society.

  10. Pedalling rate affects endurance performance during high-intensity cycling

    DEFF Research Database (Denmark)

    Nielsen, Jens Steen; Hansen, Ernst Albin; Sjøgaard, Gisela

    2004-01-01

    , such as muscle fibre type composition and power reserve, relate to endurance time. Twenty males underwent testing to determine their maximal oxygen uptake (VO(2max)), power output corresponding to 90% of VO(2max) at 80 rpm (W90), FCPR at W90, percentage of slow twitch muscle fibres (% MHC I), maximal leg power...... time was negatively related to VO(2max), W90 and % MHC I, while positively related to power reserve. In conclusion, at group level, endurance time was longer at FCPR and at a pedalling rate 25% lower compared to a pedalling rate 25% higher than FCPR. Further, inter-individual physiological variables......The purpose of this study into high-intensity cycling was to: (1) test the hypothesis that endurance time is longest at a freely chosen pedalling rate (FCPR), compared to pedalling rates 25% lower (FCPR-25) and higher (FCPR+25) than FCPR, and (2) investigate how physiological variables...

  11. Indirect Methods of Assessing Maximal Oxygen Uptake in Rowers: Practical Implications for Evaluating Physical Fitness in a Training Cycle.

    Science.gov (United States)

    Klusiewicz, Andrzej; Borkowski, Lech; Sitkowski, Dariusz; Burkhard-Jagodzińska, Krystyna; Szczepańska, Beata; Ładyga, Maria

    2016-04-01

    The aim of the study was to evaluate the usefulness of indirect methods of assessment of VO2max for estimation of physical capacity of trained male and female rowers during a training cycle. A group of 8 female and 14 male rowers performed the maximal intensity test simulating the regatta distance (a 2 km test) and a submaximal incremental exercise test on a rowing ergometer. The suitability of the indirect methods of predicting VO2max during the training cycle was evaluated by performing the tests twice: in females at an interval of five months and in males at an interval of seven months. To indirectly estimate VO2max, regression formulas obtained for the linear relationship between the examined effort indices were utilized based on 1) mean power obtained in the 2 km test, and 2) submaximal exercises after the estimation of PWC170. Although the suitability of the two indirect methods of assessment of VO2max was statisticaly confirmed, their usefulness for estimation of changes in physical fitness of trained rowers during the training cycle was rather low. Such an opinion stems from the fact that the total error of these methods (range between 4.2-7.7% in female and 5.1-7.4% in male rowers) was higher than the real differences in VO2max values determined in direct measurements (between the first and the second examination maximal oxygen uptake rose by 3.0% in female rowers and decreased by 4.3% in male rowers).

  12. The effect of a low carbohydrate beverage with added protein on cycling endurance performance in trained athletes.

    Science.gov (United States)

    Ferguson-Stegall, Lisa; McCleave, Erin L; Ding, Zhenping; Kammer, Lynne M; Wang, Bei; Doerner, Phillip G; Liu, Yang; Ivy, John L

    2010-10-01

    Ingesting carbohydrate plus protein during prolonged variable intensity exercise has demonstrated improved aerobic endurance performance beyond that of a carbohydrate supplement alone. The purpose of the present study was to determine if a supplement containing a mixture of different carbohydrates (glucose, maltodextrin, and fructose) and a moderate amount of protein given during endurance exercise would increase time to exhaustion (TTE), despite containing 50% less total carbohydrate than a carbohydrate-only supplement. We also sought post priori to determine if there was a difference in effect based on percentage of ventilatory threshold (VT) at which the subjects cycled to exhaustion. Fifteen trained male and female cyclists exercised on 2 separate occasions at intensities alternating between 45 and 70% VO2max for 3 hours, after which the workload increased to ∼74-85% VO2max until exhaustion. Supplements (275 mL) were provided every 20 minutes during exercise, and these consisted of a 3% carbohydrate/1.2% protein supplement (MCP) and a 6% carbohydrate supplement (CHO). For the combined group (n = 15), TTE in MCP did not differ from CHO (31.06 ± 5.76 vs. 26.03 ± 4.27 minutes, respectively, p = 0.064). However, for subjects cycling at or below VT (n = 8), TTE in MCP was significantly greater than for CHO (45.64 ± 7.38 vs. 35.47 ± 5.94 minutes, respectively, p = 0.006). There were no significant differences in TTE for the above VT group (n = 7). Our results suggest that, compared to a traditional 6% CHO supplement, a mixture of carbohydrates plus a moderate amount of protein can improve aerobic endurance at exercise intensities near the VT, despite containing lower total carbohydrate and caloric content.

  13. A systematic review and meta-analysis comparing cardiopulmonary exercise test values obtained from the arm cycle and the leg cycle respectively in healthy adults

    DEFF Research Database (Denmark)

    Larsen, Rasmus Tolstrup; Christensen, Jan; Tang, Lars Hermann

    2016-01-01

    INTRODUCTION: The cardiopulmonary exercise test (CPET) assesses maximal oxygen uptake (VO2max) and is commonly performed on a leg cycle ergometer (LC). However, some individuals would rather perform the CPET on an arm cycle ergometer (AC). OBJECTIVE: The objectives of this study were to undertake...... a systematic review and meta-analysis of the difference in VO2max achieved by AC compared to LC in healthy adults and to explore factors that may be predictive of this difference. METHODS: MEDLINE, EMBASE, CINAHL, and PEDro were searched in April 2015. The differences in VO2max (ACLCdiff) were pooled across....../min with a mean ACLCratio of 0.70. The ACLCdiff was lower in studies with higher mean age and lower aerobic capacity. CONCLUSION: There is linear association between the AC and LC values in healthy adults. The AC values were on average 70% of the LC values. The magnitude of this difference appeared to be reduced...

  14. A Systematic Review and Meta-analysis Comparing Cardiopulmonary Exercise Test Values Obtained From the Arm Cycle and the Leg Cycle Respectively in Healthy Adults

    DEFF Research Database (Denmark)

    Larsen, Rasmus Tolstrup; Christensen, Jan; Tang, Lars Hermann

    2016-01-01

    INTRODUCTION: The cardiopulmonary exercise test (CPET) assesses maximal oxygen uptake (VO2max) and is commonly performed on a leg cycle ergometer (LC). However, some individuals would rather perform the CPET on an arm cycle ergometer (AC). OBJECTIVE: The objectives of this study were to undertake...... a systematic review and meta-analysis of the difference in VO2max achieved by AC compared to LC in healthy adults and to explore factors that may be predictive of this difference. METHODS: MEDLINE, EMBASE, CINAHL, and PEDro were searched in April 2015. The differences in VO2max (ACLCdiff) were pooled across....../min with a mean ACLCratio of 0.70. The ACLCdiff was lower in studies with higher mean age and lower aerobic capacity. CONCLUSION: There is linear association between the AC and LC values in healthy adults. The AC values were on average 70% of the LC values. The magnitude of this difference appeared to be reduced...

  15. Low-protein vegetarian diet does not have a short-term effect on blood acid–base status but raises oxygen consumption during submaximal cycling

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    Hietavala Enni-Maria

    2012-11-01

    Full Text Available Abstract Background Acid–base balance refers to the equilibrium between acids and bases in the human body. Nutrition may affect acid–base balance and further physical performance. With the help of PRAL (potential renal acid load, a low-protein vegetarian diet (LPVD was designed to enhance the production of bases in body. The aim of this study was to investigate if LPVD has an effect on blood acid–base status and performance during submaximal and maximal aerobic cycling. Methods Nine healthy, recreationally active men (age 23.5 ± 3.4 yr participated in the study and were randomly divided into two groups in a cross-over study design. Group 1 followed LPVD for 4 days and group 2 ate normally (ND before performing a cycle ergometer test. The test included three 10-min stages at 40, 60 and 80% of VO2max. The fourth stage was performed at 100% of VO2max until exhaustion. After 10–16 days, the groups started a second 4-day diet, and at the end performed the similar ergometer test. Venous blood samples were collected at the beginning and at the end of both diet periods and after every stage cycled. Results Diet caused no significant difference in venous blood pH, strong ion difference (SID, total concentration of weak acids (Atot, partial pressure of CO2 (pCO2 or HCO3- at rest or during cycling between LPVD and ND. In the LPVD group, at rest SID significantly increased over the diet period (38.6 ± 1.8 vs. 39.8 ± 0.9, p=0.009. Diet had no significant effect on exercise time to exhaustion, but VO2 was significantly higher at 40, 60 and 80% of VO2max after LPVD compared to ND (2.03 ± 0.25 vs. 1.82 ± 0.21 l/min, p=0.035; 2.86 ± 0.36 vs. 2.52 ± 0.33 l/min, p Conclusion There was no difference in venous blood acid–base status between a 4-day LPVD and ND. VO2 was increased during submaximal cycling after LPVD suggesting that the exercise economy was poorer. This had no further effect on maximal aerobic performance. More studies are needed to

  16. Low-protein vegetarian diet does not have a short-term effect on blood acid-base status but raises oxygen consumption during submaximal cycling.

    Science.gov (United States)

    Hietavala, Enni-Maria; Puurtinen, Risto; Kainulainen, Heikki; Mero, Antti A

    2012-11-26

    Acid-base balance refers to the equilibrium between acids and bases in the human body. Nutrition may affect acid-base balance and further physical performance. With the help of PRAL (potential renal acid load), a low-protein vegetarian diet (LPVD) was designed to enhance the production of bases in body. The aim of this study was to investigate if LPVD has an effect on blood acid-base status and performance during submaximal and maximal aerobic cycling. Nine healthy, recreationally active men (age 23.5 ± 3.4 yr) participated in the study and were randomly divided into two groups in a cross-over study design. Group 1 followed LPVD for 4 days and group 2 ate normally (ND) before performing a cycle ergometer test. The test included three 10-min stages at 40, 60 and 80% of VO2max. The fourth stage was performed at 100% of VO2max until exhaustion. After 10-16 days, the groups started a second 4-day diet, and at the end performed the similar ergometer test. Venous blood samples were collected at the beginning and at the end of both diet periods and after every stage cycled. Diet caused no significant difference in venous blood pH, strong ion difference (SID), total concentration of weak acids (Atot), partial pressure of CO2 (pCO2) or HCO3- at rest or during cycling between LPVD and ND. In the LPVD group, at rest SID significantly increased over the diet period (38.6 ± 1.8 vs. 39.8 ± 0.9, p=0.009). Diet had no significant effect on exercise time to exhaustion, but VO2 was significantly higher at 40, 60 and 80% of VO2max after LPVD compared to ND (2.03 ± 0.25 vs. 1.82 ± 0.21 l/min, p=0.035; 2.86 ± 0.36 vs. 2.52 ± 0.33 l/min, p<0.001 and 4.03 ± 0.50 vs. 3.54 ± 0.58 l/min, p<0.001; respectively). There was no difference in venous blood acid-base status between a 4-day LPVD and ND. VO2 was increased during submaximal cycling after LPVD suggesting that the exercise economy was poorer. This had no further effect on maximal aerobic performance. More studies are needed to

  17. Effects Of Cadence on Aerobic Capacity Following a Prolonged, Varied Intensity Cycling Trial

    Directory of Open Access Journals (Sweden)

    Charles L. Stebbins

    2014-03-01

    Full Text Available We determined if high cadences, during a prolonged cycling protocol with varying intensities (similar to race situations decrease performance compared to cycling at a lower, more energetically optimal, cadence. Eight healthy, competitive male road cyclists (35 ± 2 yr cycled for 180 min at either 80 or 100 rpm (randomized with varying intensities of power outputs corresponding to 50, 65 and 80% of VO2max. At the end of this cycling period, participants completed a ramped exercise test to exhaustion at their preferred cadence (90 ± 7 rpm. There were no cadence differences in blood glucose, respiratory exchange ratio or rate of perceived exertion. Heart Rate, VO2 and blood lactate were higher at 100 rpm vs. 80 rpm. The total energy cost while cycling during the 65% and 80% VO2max intervals at 100 rpm (15.2 ± 2.7 and 19.1 ± 2.5 kcal∙min-1, respectively were higher than at 80 rpm (14.3 ± 2.7 and 18.3± 2.2 kcal∙min-1, respectively (p < 0.05. Gross efficiency was higher at 80 rpm vs. 100 rpm during both the 65% (22.8 ± 1.0 vs. 21.3 ± 4.5% and the 80% (23.1 vs. 22.1 ± 0.9% exercise intensities (P< 0.05. Maximal power during the performance test (362 ± 38 watts was greater at 80 rpm than 100 rpm (327 ± 27 watts (p < 0.05. Findings suggest that in conditions simulating those seen during prolonged competitive cycling, higher cadences (i.e., 100 vs. 80 rpm are less efficient, resulting in greater energy expenditure and reduced peak power output during maximal performance.

  18. Tricarboxylic-acid-cycle intermediates and cycle endurance capacity.

    Science.gov (United States)

    Brown, Amy C; Macrae, Holden S H; Turner, Nathan S

    2004-12-01

    The purpose of this study was to determine whether ingestion of a multinutrient supplement containing 3 tricarboxylic-acid-cycle intermediates (TCAIs; pyridoxine-alpha-ketoglutarate, malate, and succinate) and other substances potentially supporting the TCA cycle (such as aspartate and glutamate) would improve cyclists' time to exhaustion during a submaximal endurance-exercise test (approximately 70 % to 75 % VO2peak) and rate of recovery. Seven well-trained male cyclists (VO2max 67.4 2.1 mL x kg(-1) x in(-1), 28.6 +/- 2.4 y) participated in a randomized, double-blind crossover study for 7 wk. Each took either the treatment or a placebo 30 min before and after their normal training sessions for 3 wk and before submaximal exercise tests. There were no significant differences between the TCAI group (KI) and placebo group (P) in time to exhaustion during cycling (KI = 105 +/- 18, P = 113 +/- 11 min); respiratory-exchange ratio at 20-min intervals; blood lactate and plasma glucose before, after, and at 30-min intervals during exercise; perceived exertion at 20-min intervals during exercise; or time to fatigue after the 30-min recovery (KI = 16.1 +/- 3.2, P = 15 +/- 2 min). Taking a dietary sport supplement containing several TCAIs and supporting substances for 3 wk does not improve cycling performance at 75 % VO2peak or speed recovery from previously fatiguing exercise.

  19. Fat-free mass and excess post-exercise oxygen consumption in the 40 minutes after short-duration exhaustive exercise in young male Japanese athletes.

    Science.gov (United States)

    Tahara, Yasuaki; Moji, Kazuhiko; Honda, Sumihisa; Nakao, Rieko; Tsunawake, Noriaki; Fukuda, Rika; Aoyagi, Kiyoshi; Mascie-Taylor, Nicholas

    2008-05-01

    The relationship between fat-free mass (FFM) and excess post-exercise oxygen consumption (EPOC) has not been well researched because of the relatively small number of subjects studied. This study investigated the effects of FFM on EPOC and EPOC/maximum oxygen consumption. 250 Japanese male athletes between 16 and 21 years old from Nagasaki prefecture had their EPOC measured up to 40 minutes after short-duration exhaustive exercise. The value was named as EPOC40 min. The proportions of EPOC up to 1, 3, 6, 10, and 25 minutes to EPOC40 min were calculated and named as P1, P3, P6, P10, and P25, respectively. Body size and composition, VO2max and resting metabolic rate (RMR) were also measured. Mean EPOC40 min was 9.04 L or 158 ml/kg FFM. EPOC40 min was related to FFM (r=0.55, pEPOC40 min to VO2max was related to FFM (r=0.28, pEPOC40 min/FFM, EPOC40 min/VO2max, and FFM. Athletes who had larger FFM had larger EPOC40 40 min and EPOC40 40 min/VO2max, and smaller P1, P3, P10, and P25.

  20. A SYSTEMATIC REVIEW AND META-ANALYSIS COMPARING CARDIOPULMONARY EXERCISE TEST VALUES OBTAINED FROM THE ARM CYCLE AND THE LEG CYCLE RESPECTIVELY IN HEALTHY ADULTS

    DEFF Research Database (Denmark)

    Larsen, Rasmus Tolstrup; Christensen, Jan; Tang, Lars Hermann

    2016-01-01

    INTRODUCTION: The cardiopulmonary exercise test (CPET) assesses maximal oxygen uptake (VO2max) and is commonly performed on a leg cycle ergometer (LC). However, some individuals would rather perform the CPET on an arm cycle ergometer (AC). OBJECTIVE: The objectives of this study were to undertake...

  1. Muscle fibre conduction velocity and cardiorespiratory response during incremental cycling exercise in young and older individuals with different training status.

    Science.gov (United States)

    Lenti, M; De Vito, G; Sbriccoli, P; Scotto di Palumbo, A; Sacchetti, M

    2010-08-01

    We investigated the effect of ageing and training on muscle fibre conduction velocity (MFCV) and cardiorespiratory response during incremental cycling exercise. Eight young (YT; 24+/-5 yrs) and eight older (OT; 64+/-3 yrs) cyclists, together with eight young (YU; 27+/-4 yrs) and eight older (OU; 63+/-2 yrs) untrained individuals underwent to an incremental maximal test on a cycle ergometer. Ventilatory threshold (VT), respiratory compensation point (RCP) and maximal oxygen uptake (VO(2)max) were identified and MFCV recorded from the vastus lateralis muscle using surface electromyography with linear arrays electrodes. In YT MFCV increased with the exercise intensity, reaching a peak of 4.99+/-1.02 [m/s] at VT. Thereafter, and up to VO(2)max, MFCV declined. In YU MFCV showed a similar trend although the peak [4.55+/-0.53m/s] was observed, at 75% of VO(2)max an intensity higher than VT (66% of VO(2)max). In both YT and YU MFCV did not decline until RPC, which occurred at 78% VO(2)max in YU and at 92% VO(2)max (P<0.01) in YT. Differently from young individuals, MFCV in older subjects did not increase with exercise intensity. Moreover, maximal MFCV in OU was significantly lower [3.53+/-0.40 m/s;] than that of YT (P<0.005) and YU (P<0.05). The present study shows that, especially in young individuals, MFCV reflects cardiorespiratory response during incremental dynamic cyclic exercise and hence can be used to investigate motor unit recruitment strategies.

  2. Biomechanical events in the time to exhaustion at maximum aerobic speed.

    Science.gov (United States)

    Gazeau, F; Koralsztein, J P; Billat, V

    1997-10-01

    Recent studies reported good intra-individual reproducibility, but great inter-individual variation in a sample of elite athletes, in time to exhaustion (tlim) at the maximal aerobic speed (MAS: the lowest speed that elicits VO2max in an incremental treadmill test). The purpose of the present study was, on the one hand, to detect modifications of kinematic variables at the end of the tlim of the VO2max test and, on the other hand, to evaluate the possibility that such modifications were factors responsible for the inter-individual variability in tlim. Eleven sub-elite male runners (Age = 24 +/- 6 years; VO2max = 69.2 +/- 6.8 ml kg-1 min-1; MAS = 19.2 +/- 1.45 km h-1; tlim = 301.9 +/- 82.7 s) performed two exercise tests on a treadmill (0% slope): an incremental test to determine VO2max and MAS, and an exhaustive constant velocity test to determine tlim at MAS. Statistically significant modifications were noted in several kinematic variables. The maximal angular velocity of knee during flexion was the only variable that was both modified through the tlim test and influenced the exercise duration. A multiple correlation analysis showed that tlim was predicted by the modifications of four variables (R = 0.995, P < 0.01). These variables are directly or indirectly in relation with the energic cost of running. It was concluded that runners who demonstrated stable running styles were able to run longer during MAS test because of optimal motor efficiency.

  3. Monitoring Perceived Stress and Recovery in Relation to Cycling Performance in Female Athletes

    NARCIS (Netherlands)

    Otter, R. T. A.; Brink, M. S.; van der Does, H. T. D.; Lemmink, K. A. P. M.

    2016-01-01

    The purpose was to investigate perceived stress and recovery related to cycling performance of female athletes over one full year. 20 female athletes ( age, 27 +/- 8 years; VO2max, 50.3 +/- 4.6 mL center dot kg(-1) center dot min(-1)) were measured 8 times in one year to determine perceived stress a

  4. Median power frequency of the surface electromyogram and blood lactate concentration in incremental cycle ergometry

    NARCIS (Netherlands)

    Jansen, R; Ament, W; Verkerke, GJ; Hof, AL

    1997-01-01

    The electromyogram (EMG) median power frequency of the vastus lateralis and flexor digitorum superficialis muscles was measured in 12 subjects during cycle ergometry with step-wise increasing exercise intensities up to 100% of VO2max. Blood lactate concentration was measured to investigate the relat

  5. Effect of carbohydrate availability on time to exhaustion in exercise performed at two different intensities

    Directory of Open Access Journals (Sweden)

    A.E. Lima-Silva

    2009-05-01

    Full Text Available This study examined the effects of pre-exercise carbohydrate availability on the time to exhaustion for moderate and heavy exercise. Seven men participated in a randomized order in two diet and exercise regimens each lasting 3 days with a 1-week interval for washout. The tests were performed at 50% of the difference between the first (LT1 and second (LT2 lactate breakpoint for moderate exercise (below LT2 and at 25% of the difference between the maximal load and LT2 for heavy exercise (above LT2 until exhaustion. Forty-eight hours before each experimental session, subjects performed a 90-min cycling exercise followed by 5-min rest periods and a subsequent 1-min cycling bout at 125% VO2max/1-min rest periods until exhaustion to deplete muscle glycogen. A diet providing 10% (CHOlow or 65% (CHOmod energy as carbohydrates was consumed for 2 days until the day of the experimental test. In the exercise below LT2, time to exhaustion did not differ between the CHOmod and the CHOlow diets (57.22 ± 24.24 vs 57.16 ± 25.24 min. In the exercise above LT2, time to exhaustion decreased significantly from 23.16 ± 8.76 min on the CHOmod diet to 18.30 ± 5.86 min on the CHOlow diet (P < 0.05. The rate of carbohydrate oxidation, respiratory exchange ratio and blood lactate concentration were reduced for CHOlow only during exercise above LT2. These results suggest that muscle glycogen depletion followed by a period of a low carbohydrate diet impairs high-intensity exercise performance.

  6. Leg stiffness modulation during exhaustive stretch-shortening cycle exercise.

    Science.gov (United States)

    Kuitunen, S; Kyröläinen, H; Avela, J; Komi, P V

    2007-02-01

    The present study examined the effects of muscle activity modulation on leg stiffness during an exhaustive stretch-shortening cycle (SSC) exercise in eight male subjects. Reaction force, electromyography (EMG) of the soleus (Sol), gastrocnemius (Ga) and vastus lateralis (VL) muscles and sledge seat position were recorded during the SSC exercise, consisting of 100 maximal intermittent drop jumps followed by a continuous submaximal jumping until exhaustion, on a sledge apparatus. Metabolic loading was determined by measuring blood lactate (La). No change was found in leg stiffness during the maximal jumps, whereas the subsequent submaximal jumping induced a significant reduction by 27+/-12% (PEMG ratio between the braking and push-off phases in Sol (r=0.81, PEMG ratio at the end of the submaximal jumping in Sol (r=-0.88, Pmodulation between the braking and push-off phases in the triceps surae muscle, particularly in Ga, plays an important role in leg stiffness adjustments during fatiguing SSC exercise. It is suggested that efficient activity modulation (i.e. high EMG ratio) of the triceps surae muscle during an intensive fatiguing SSC exercise may postpone the exhaustion and development of metabolic fatigue.

  7. TREADMILL AND CYCLE ERGOMETER TESTS ARE INTERCHANGEABLE TO MONITOR TRIATHLETES ANNUAL TRAINING

    Directory of Open Access Journals (Sweden)

    Fabien A. Basset

    2003-09-01

    Full Text Available The purpose of this study was to verify the use of a single test to obtain annual training guidelines applicable to multiple modes of training. Eight triathletes (4 females, 4 males were tested 3 times during their training year (Phase I; Phase II; Phase III on a treadmill and cycle ergometer. Cardio-respiratory variables were calculated at standardized percentages of maximal oxygen uptake (VO2max; 50-100%. VO2max differences between tests reached 6% in every testing session (p 0.01. VO2max was stable for both tests throughout the season. The ANOVA (3 phases x 2 tests x 6 intensities demonstrated that there was a significant difference for heart rate (HRs; p 0.05 between tests in Phase I only. However, the nonparametric sign test did not show any significant differences in any phase. These results demonstrated that triathletes could use the relationship between HR and % VO2max collected during a treadmill or a cycle ergometer test to obtain interchangeable reference HRs for monitoring their running and cycling training bouts in high volume and/or high intensity phases of their training year.

  8. Cadetes of the Academia do Polícia Militar do Estado do Rio de Janeiro Correlación entre VO2 max, gordura relativa y perfil lipídico, en cadetes de la Academia de Policía Militar del Estado de Río de Janeiro

    Directory of Open Access Journals (Sweden)

    E. H. M. Dantas

    2010-09-01

    Full Text Available The objective of the present study was to verify the correlation level among the max, the relative fat and the profile lipídico of 51 Cadets (Age = 23.63 3.58 years; Weight = 74.13 ± 10.46 kg; Height = 1.76 ± 0.06 m; IMC = 23.99 2.76 kg/m2, of the masculine gender, of the Academy of the Military police of the State of Rio de Janeiro, of the year of 2007. The subjects were active and participants of the military physical training (TFM accomplished five times a week, with duration of 60 minutes for session. They were appraised: the max for ergoespirometria (I record of progressive effort, with constant inclination of 3% and initial speed of 4,0km/h, the relative fat (% G - I record of three cutaneous folds and the profile lipídico, through the method Enzymatic Calorimétrico in the variables: total cholesterol (CT, triglicérides (TG, lipoproteína of density high-cholesterol (HDL-C and lipoproteína of density low-cholesterol (LDL-C. The test of correlation of Spearman presented correlation significant between max and TG (r = -0,289; p = 0,04,  max and HDL-C (r = 0,277; p = 0,049,% G and TG (r = 0,296; p = 0,035,% G and HDL-C (r = 0,338; p = 0,015. Like this, these discoveries point a discreet relationship between the profile lipídico and the maximum consumption of oxygen corroborating the need to consider other factors as the feeding and the intensity of the exercises in the investigation of this relationship.

    Key Words: training,  VO2 max, relative fat, lipidic profile.

     

    El objetivo del presente estudio es establecer el nivel de correlación entre el  VO2 max, la grasa relativa y el perfil lipídico de 51 cadetes varones (Edad = 23.63 ± 3.58 años; Peso = 74.13 ± 10.46 Kg.; Talla = 1.76  ± 0.06 m; IMC = 23.99 ± 2.76 Kg. /m2 de la Academia de la Policía Militar del Estado de Río de Janeiro, del año de 2007. Los sujetos son f

  9. Effects of cadence on aerobic capacity following a prolonged, varied intensity cycling trial.

    Science.gov (United States)

    Stebbins, Charles L; Moore, Jesse L; Casazza, Gretchen A

    2014-01-01

    We determined if high cadences, during a prolonged cycling protocol with varying intensities (similar to race situations) decrease performance compared to cycling at a lower, more energetically optimal, cadence. Eight healthy, competitive male road cyclists (35 ± 2 yr) cycled for 180 min at either 80 or 100 rpm (randomized) with varying intensities of power outputs corresponding to 50, 65 and 80% of VO2max. At the end of this cycling period, participants completed a ramped exercise test to exhaustion at their preferred cadence (90 ± 7 rpm). There were no cadence differences in blood glucose, respiratory exchange ratio or rate of perceived exertion. Heart Rate, VO2 and blood lactate were higher at 100 rpm vs. 80 rpm. The total energy cost while cycling during the 65% and 80% VO2max intervals at 100 rpm (15.2 ± 2.7 and 19.1 ± 2.5 kcal∙min(-1), respectively) were higher than at 80 rpm (14.3 ± 2.7 and 18.3± 2.2 kcal∙min(-1), respectively) (p < 0.05). Gross efficiency was higher at 80 rpm vs. 100 rpm during both the 65% (22.8 ± 1.0 vs. 21.3 ± 4.5%) and the 80% (23.1 vs. 22.1 ± 0.9%) exercise intensities (P< 0.05). Maximal power during the performance test (362 ± 38 watts) was greater at 80 rpm than 100 rpm (327 ± 27 watts) (p < 0.05). Findings suggest that in conditions simulating those seen during prolonged competitive cycling, higher cadences (i.e., 100 vs. 80 rpm) are less efficient, resulting in greater energy expenditure and reduced peak power output during maximal performance. Key PointsWhen competitive cyclists perform prolonged exercise that simulates racing conditions (i.e., variable, low-moderate submaximal cycling), a higher cadence results in excess energy expenditure and lower gross efficiency compared to a lower cadence at the same power output.Consequently, maximal power output is reduced during a subsequent exercise bout to exhaustion after using a higher cadence.Selection of a lower, more energetically optimal cadence during prolonged

  10. Sex-Specific Equations to Estimate Maximum Oxygen Uptake in Cycle Ergometry

    Directory of Open Access Journals (Sweden)

    Christina G. de Souza e Silva

    2015-01-01

    Full Text Available Abstract Background: Aerobic fitness, assessed by measuring VO2max in maximum cardiopulmonary exercise testing (CPX or by estimating VO2max through the use of equations in exercise testing, is a predictor of mortality. However, the error resulting from this estimate in a given individual can be high, affecting clinical decisions. Objective: To determine the error of estimate of VO2max in cycle ergometry in a population attending clinical exercise testing laboratories, and to propose sex-specific equations to minimize that error. Methods: This study assessed 1715 adults (18 to 91 years, 68% men undertaking maximum CPX in a lower limbs cycle ergometer (LLCE with ramp protocol. The percentage error (E% between measured VO2max and that estimated from the modified ACSM equation (Lang et al. MSSE, 1992 was calculated. Then, estimation equations were developed: 1 for all the population tested (C-GENERAL; and 2 separately by sex (C-MEN and C-WOMEN. Results: Measured VO2max was higher in men than in WOMEN: -29.4 ± 10.5 and 24.2 ± 9.2 mL.(kg.min-1 (p < 0.01. The equations for estimating VO2max [in mL.(kg.min-1] were: C-GENERAL = [final workload (W/body weight (kg] x 10.483 + 7; C-MEN = [final workload (W/body weight (kg] x 10.791 + 7; and C-WOMEN = [final workload (W/body weight (kg] x 9.820 + 7. The E% for MEN was: -3.4 ± 13.4% (modified ACSM; 1.2 ± 13.2% (C-GENERAL; and -0.9 ± 13.4% (C-MEN (p < 0.01. For WOMEN: -14.7 ± 17.4% (modified ACSM; -6.3 ± 16.5% (C-GENERAL; and -1.7 ± 16.2% (C-WOMEN (p < 0.01. Conclusion: The error of estimate of VO2max by use of sex-specific equations was reduced, but not eliminated, in exercise tests on LLCE.

  11. The Comparison of Two Incremental Exercise Test Models of Ramp and GXT in Direct Measurement of VO2max%Ramp与GXT两种递增负荷模式在VO2max直接测试中的比较研究

    Institute of Scientific and Technical Information of China (English)

    胡国鹏; 王振; 刘无逸; 冯魏; 孟妍

    2016-01-01

    比较连续斜坡式递增负荷模式(Ramp)和连续分级递增负荷模式(graded exercise text,GXT)在最大摄氧量直接测试中的生理变量变化特征.方法:对20名体力活动良好的男性受试者分剐进行3次不同负荷模式的极量力竭测试,3种负荷模式分别为GXT、Ramp和105%最大负荷持续运动(constant exercise test,105 %CT).结果:Ramp与GXT测试结果相比,两测试中最大摄氧量(VO2 max、VO2max/kg)高度相关(r=0.726~0.882,P<0.01)且无显著性差异(P<0.01);而最高功率(Wmax)、血乳酸(La)均表现为Ramp测试值低于GXT测试值;两测试时长(T)高度相关且Ramp测试值较短;Ramp测试中VO2 max、VO2 max/kg、最高心率(HRmax)、呼吸商(RER)和105%CT测试中值无显著性差别.GXT、Ramp两测试中,根据平台定义不同所达到平台的百分比不同.结论:在同样的平均递增负荷幅度下,两负荷方案对不同峰值参数存在不同影响;Ramp可作为直接测试最大摄氧量替代方案,并且所达到的峰值功率及时间较低、较短;依照最大摄氧量不同平台判定标准,平台出现概率受测试方案及判定标准影响较大,ACSM推荐的平台标准不适用于Ramp测试.

  12. Physiological determinants of the cycling time trial.

    Science.gov (United States)

    Støren, Øyvind; Ulevåg, Kåre; Larsen, Morten H; Støa, Eva M; Helgerud, Jan

    2013-09-01

    The purpose of this study was to examine the physiological determinants of endurance cycling time trial (TT) performance in a heterogeneous group of competitive male road cyclists. About 15 male cyclists who had all competed in cycling the preceding season were tested for the anthropometric variables height, body weight, leg length, ankle circumference, and body fat percentage. They were also tested for maximal oxygen consumption (VO2max), lactate threshold (LT), metabolic cost of cycling (CC), peak power output and average power output during a 30-second Wingate test, 1 repetition maximum and peak power in half squats, and a TT test on an ergometer. Heart rate and cadence (rounds per minute, RPM) were continuously measured during all cycle tests. Pearson Bivariate correlation tests and single linear regression tests were performed to obtain correlation coefficients (r), effect size (F), standard error of estimate (SEE), and 95% confidence interval. The single variable that correlated best with TT performance was power output at LT (r = 0.86, p equation representing both aerobic and anaerobic endurance capacity TT(w) = 0.95 ([VO2max/CC] TT%VO2max) + 0.05 (Wingate average) correlated strongly with TT laboratory performance (r = 0.93, p < 0.01, SEE = 5.7%). None of the strength, power, or anthropometric variables correlated significantly with TT laboratory performance.

  13. Indirect Methods of Assessing Maximal Oxygen Uptake in Rowers: Practical Implications for Evaluating Physical Fitness in a Training Cycle

    Directory of Open Access Journals (Sweden)

    Klusiewicz Andrzej

    2016-04-01

    Full Text Available The aim of the study was to evaluate the usefulness of indirect methods of assessment of VO2max for estimation of physical capacity of trained male and female rowers during a training cycle. A group of 8 female and 14 male rowers performed the maximal intensity test simulating the regatta distance (a 2 km test and a submaximal incremental exercise test on a rowing ergometer. The suitability of the indirect methods of predicting VO2max during the training cycle was evaluated by performing the tests twice: in females at an interval of five months and in males at an interval of seven months. To indirectly estimate VO2max, regression formulas obtained for the linear relationship between the examined effort indices were utilized based on 1 mean power obtained in the 2 km test, and 2 submaximal exercises after the estimation of PWC170. Although the suitability of the two indirect methods of assessment of VO2max was statisticaly confirmed, their usefulness for estimation of changes in physical fitness of trained rowers during the training cycle was rather low. Such an opinion stems from the fact that the total error of these methods (range between 4.2-7.7% in female and 5.1-7.4% in male rowers was higher than the real differences in VO2max values determined in direct measurements (between the first and the second examination maximal oxygen uptake rose by 3.0% in female rowers and decreased by 4.3% in male rowers.

  14. Research on the Correlation between the .VO2 max and Resting Function of Heart and Lung-Taking Female College Students in Non-Sports Professional as an Example%最大耗氧量与安静时心输出量和肺呼吸功能相关性研究--以非运动专业的青年女大学生为例

    Institute of Scientific and Technical Information of China (English)

    程宙明; 卢健; 牛俊茹; 张涛; 陈贝贝; 邱林利; 陈彩珍; 季浏

    2015-01-01

    Objective :This paper explores the correlation between .VO2 max and function of rest‐ing heart and lung ,and compare the difference in participants of different .VO2 max level be‐tween .VO2 max and function of heart and lung .Method :Testing 66 female college students’ (age :20 ± 6 ,BMI :20 .88 ± 1 .32 ) .VO2 max ,Cardiac output ,and lung function .Dividing the participants into two groups (normal or less than normal) based on the testing results .Con‐ducting Independent‐Samples T Test on each groups .Results :1) There is a significant correla‐tion between .VO2max(ml/kg/min) with VE (P 0 .05);3)The ventila‐tion volume of the“below‐average” group is significantly lower than the“normal” group while the respiration quotient of the former group is larger than the latter one’ s ( P 0 .05);5)The MET ,QLD and EVP of the participants in the“below‐average” group ,to some extent ,fluctuate with small range and lack amplitude .Conclusions :1) .VO2 max is greatly influenced by the ventilation volume and is posi‐tively correlated with the lungs breathing vibration intensity .However ,it is uncorrelated with the cardiac output in a static situation ;2) The depth of respiration of the “normal” group (in sports) is significantly higher than the“below‐average” group ,which is possibly due to a bet‐ter oxygen utilization in metabolism and energy supply ;3) Participants with different .VO2 max levels show no significant difference of heart function in a static situation ,suggesting that par‐ticipants of the“below‐average” group didn't lose on the "starting line" ;4) Participants of the“below‐average” group lacks advantage in terms of the overall Aerobic capacity ,which + also seems to affect their cardiopulmonary function when doing sports .%目的:探讨最大耗氧量(.VO2 max )与安静时心脏、肺功能的相关性,以及不同.VO2 max水平受试者的心脏和肺功能差异。方法:对66

  15. Reference Standards for Cardiorespiratory Fitness Measured With Cardiopulmonary Exercise Testing Using Cycle Ergometry: Data From the Fitness Registry and the Importance of Exercise National Database (FRIEND) Registry.

    Science.gov (United States)

    Kaminsky, Leonard A; Imboden, Mary T; Arena, Ross; Myers, Jonathan

    2017-02-01

    The importance of cardiorespiratory fitness (CRF) is well established. This report provides newly developed standards for CRF reference values derived from cardiopulmonary exercise testing (CPX) using cycle ergometry in the United States. Ten laboratories in the United States experienced in CPX administration with established quality control procedures contributed to the "Fitness Registry and the Importance of Exercise: A National Database" (FRIEND) Registry from April 2014 through May 2016. Data from 4494 maximal (respiratory exchange ratio, ≥1.1) cycle ergometer tests from men and women (20-79 years) from 27 states, without cardiovascular disease, were used to develop these references values. Percentiles of maximum oxygen consumption (VO2max) for men and women were determined for each decade from age 20 years through age 79 years. Comparisons of VO2max were made to reference data established with CPX data from treadmill data in the FRIEND Registry and previously published reports. As expected, there were significant differences between sex and age groups for VO2max (Ptests within the FRIEND Registry, the 50th percentile VO2max of men and women aged 20 to 29 years declined from 41.9 and 31.0 mLO2/kg/min to 19.5 and 14.8 mLO2/kg/min for ages 70 to 79 years, respectively. The rate of decline in this cohort was approximately 10% per decade. The FRIEND Registry reference data will be useful in providing more accurate interpretations for the US population of CPX-measured VO2max from exercise tests using cycle ergometry compared with previous approaches based on estimations of standard differences from treadmill testing reference values. Copyright © 2016 Mayo Foundation for Medical Education and Research. All rights reserved.

  16. In-season changes in heart rate recovery are inversely related to time to exhaustion but not aerobic capacity in rowers.

    Science.gov (United States)

    Haraldsdottir, K; Brickson, S; Sanfilippo, J; Dunn, W; Watson, A

    2017-06-26

    To determine if in-season changes in heart rate recovery (HRR) are related to aerobic fitness and performance in collegiate rowers. Twenty-two female collegiate rowers completed testing before and after their competitive season. Body fat percentage (BF%) was determined by dual-energy X-ray absorptiometry. Maximal aerobic capacity (VO2max ) and time to exhaustion (Tmax ) were determined during maximal rowing ergometer testing followed by 1 minute of recovery. HRR was expressed absolutely and as a percentage of maximal HR (HRR%1 min ). Variables were compared using paired Wilcoxon tests. Multivariable regression models were used to predict in-season changes in HRR using changes in VO2max and Tmax , while accounting for changes in BF%. From preseason to post-season, VO2max and BF% decreased (3.98±0.42 vs 3.78±0.35 L/min, P=.002 and 23.8±3.4 vs 21.3±3.9%, PVO2max were not associated with HRR%1 min (P>.05). In-season changes in Tmax were related to changes in HRR%1 min (β=-1.67, P=.006). In-season changes in BF% were not related to changes in HRR (P>.05 for all). HRR1 min and HRR%1 min were faster preseason to post-season, although the changes were unrelated to VO2max . Faster HRR%1 min post-season was inversely related to changes in Tmax . This suggests that HRR should not be used as a measure of aerobic capacity in collegiate rowers, but is a promising measure of training status in this population. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Cycle Analysis using Exhaust Heat of SOFC and Turbine Combined Cycle by Absorption Chiller

    Science.gov (United States)

    Takezawa, Shinya; Wakahara, Kenji; Araki, Takuto; Onda, Kazuo; Nagata, Susumu

    A power generating efficiency of solid oxide fuel cell (SOFC) and gas turbine combined cycle is fairly high. However, the exhaust gas temperature of the combined cycle is still high, about 300°C. So it should be recovered for energy saving, for example, by absorption chiller. The energy demand for refrigeration cooling is recently increasing year by year in Japan. Then, we propose here a cogeneration system by series connection of SOFC, gas turbine and LiBr absorption chiller to convert the exhaust heat to the cooling heat. As a result of cycle analysis of the combined system with 500kW class SOFC, the bottoming single-effect absorption chiller can produce the refrigerating capacity of about 120kW, and the double-effect absorption chiller can produce a little higher refrigerating capacity of about 130kW without any additional fuel. But the double-effect absorption chiller became more expensive and complex than the single-effect chiller.

  18. The influence of body position on maximal performance in cycling.

    Science.gov (United States)

    Welbergen, E; Clijsen, L P

    1990-01-01

    Six healthy male subjects performed a 3-min supramaximal test in four different cycling positions: two with different trunk angles and two with different saddle-tube angles. Maximal power output and maximal oxygen uptake (VO2max) were measured. Maximal power output was significantly higher in a standard sitting (SS, 381 W, SD 49) upright position compared to all other positions: standard racing (SR, 364 W, SD 49), recumbent backwards (RB, 355 W, SD 44) and recumbent forwards (RF, 341 W, SD 54). Although VO2max was also highest in SS (4.31 l.min-1, SD 0.5) upright position, the differences in VO2max were not significant (SR, 4.2 l.min-1, SD 0.53; RB, 4.17 l.min-1, SD 0.58; RF, 4.11 l.min-1, SD 0.66). It is concluded that (supra)maximal tests on a cycle ergometer should be performed in a sitting upright position and not in a racing position. In some cases when cycling on the road, higher speeds can be attained when sitting upright. This is especially true when cycling uphill when high power must be generated to overcome gravity but the road speed, and hence the power required to overcome air resistance, is relatively low.

  19. Mutagenicity of diesel exhaust particle extracts: influence of driving cycle and environmental temperature.

    Science.gov (United States)

    Clark, C R; Dutcher, J S; Brooks, A L; McClellan, R O; Marshall, W F; Naman, T M

    1982-01-01

    General Motors and Volkswagen diesel passenger cars (1980 and 1981 model year) were operated on a climate controlled chassis dynomometer and the particulate portion of the exhaust was collected on high volume filters. Dichloromethane extracts of the exhaust particles (soot) collected while the cars were operated under simulated highway, urban and congested urban driving cycles were assayed for mutagenicity in Salmonella strains TA-98 and TA-100. Driving pattern did not significantly influence the mutagenic potency of the exhaust particle extracts or estimates of the amount of mutagenicity emitted from the exhaust despite large differences in particle emission rates and extractable fraction of the particles. Mutagenicity of extracts of exhaust particles collected while the vehicles were operated at test chamber temperatures of 25, 50, 75 and 100 degrees F were also very similar. The results suggest that driving pattern and environmental temperature do not significantly alter the emission of genotoxic combustion products from the exhaust.

  20. Early ventilation-heart rate breakpoint during incremental cycling exercise.

    Science.gov (United States)

    Gravier, G; Delliaux, S; Ba, A; Delpierre, S; Guieu, R; Jammes, Y

    2014-03-01

    Previous observations having reported a transient hypoxia at the onset of incremental exercise, we investigated the existence of concomitant ventilatory and heart rate (HR) breakpoints.33 subjects executed a maximal cycling exercise with averaging for successive 5-s periods of HR, ventilation, tidal volume (VT), mean inspiratory flow rate (VT/Ti), and end-tidal partial pressures of O2 (PETO2) and CO2. In 10 subjects, the transcutaneous partial pressure of O2 (PtcO2) was recorded and the venous blood lactic acid (LA) concentration measured.At the beginning of exercise, PETO2 decreased, reaching a nadir, then progressively increased until the exercise ended. PtcO2 varied in parallel. Whether or not a 0-W cycling period preceded the incremental exercise, the rate of changes in VE, VT, VT/Ti and HR significantly increased when the nadir PO2 was reached. The ventilatory/ HR breakpoint was measured at 33±4% of VO2max, whereas the ventilatory threshold (VTh) was detected at 67±4% of VO2max and LA began to increase at 45 to 50% of VO2max.During incremental cycling exercise, we identified the existence of HR and ventilatory breakpoints in advance of both lactate and ventilatory thresholds which coincided with modest hypoxia and hypercapnia. © Georg Thieme Verlag KG Stuttgart · New York.

  1. The variation after different weeks HIIT and moderate-intensity exercise in rats ’ VO2 max and cardiovascular risk indicator%不同时长 HIIT与中等强度运动后大鼠痹VO2 max及血液心血管风险指标的变化

    Institute of Scientific and Technical Information of China (English)

    王林佳; 苏浩; 梁春瑜; 严翊; 赵岩; 张一民

    2016-01-01

    Purpose :as a new movement ,HIIT ( High‐intensity Interval T raining ) has a better effects on improving cardiorespiratory endurance than moderate training ,but there are less studies on the safety of movement .This study discussion the variation in rats ’ VO2 max and cardiovascular risk index after different time HIIT and moderate exercise .Compared two ways of exercise in improving cardiorespiratory endurance sports as well as the changes in cardiovas‐cular risk indicators ,Clearly which can improve cardiorespiratory endurance effective safety and also provide a theoretical basis for public health movement selection .Methods :120 6‐week‐old male Wistar rats were randomly divided into four groups (N = 30 ):2 weeks (group C ) ,4 weeks(group D) ,6 weeks(group E) ,10 weeks(group F) .Each group was divided into the control ,moderate‐intensity exercise and HIIT three subgroups of 10 rats each .All the rats free to gather the food and drinking water .Sedentary control rats do not exercise ,moderate intensi‐ty and HIIT rats were carried 50min exercise every day ,5times/week .Before the start of training 2 ,4 ,6 ,10 weeks ,Each group of rats were carried out maximal oxygen uptake test .24 hours after test ,rats were intraperitoneal injection by 2% sodium pentobarbital of anesthetized and get Abdominal aortic blood around 8 ml into the anticoagulant tube after centrifugation ,se‐rum to -80℃ under test .The determination of serum creatine kinase (CK ) ,aspertate amin‐otransferase(AST ) ,angiotensin II (AngII) .Different exercise group and the comparison be‐tween different exercise time of group adopt single factor analysis of variance ,the results are expressed as mean ± standard deviation .Results :(1 )after 4 weeks of training ,HIIT rats VO2 max appear stable upward trend but moderate group appears upward trend after 6 weeks . at 10 weeks HIIT group rats’ VO2 max (3 456 .4 ± 335 .427 ml/kg/min) was significantly higher than the control rats (2

  2. Influence of prior exercise on VO2 kinetics subsequent exhaustive rowing performance.

    Science.gov (United States)

    Sousa, Ana; Ribeiro, João; Sousa, Marisa; Vilas-Boas, João Paulo; Fernandes, Ricardo J

    2014-01-01

    Prior exercise has the potential to enhance subsequent performance by accelerating the oxygen uptake (VO2) kinetics. The present study investigated the effects of two different intensities of prior exercise on pulmonary VO2 kinetics and exercise time during subsequent exhaustive rowing exercise. It was hypothesized that in prior heavy, but not prior moderate exercise condition, overall VO2 kinetics would be faster and the VO2 primary amplitude would be higher, leading to longer exercise time at VO2max. Six subjects (mean ± SD; age: 22.9±4.5 yr; height: 181.2±7.1 cm and body mass: 75.5±3.4 kg) completed square-wave transitions to 100% of VO2max from three different conditions: without prior exercise, with prior moderate and heavy exercise. VO2 was measured using a telemetric portable gas analyser (K4b(2), Cosmed, Rome, Italy) and the data were modelled using either mono or double exponential fittings. The use of prior moderate exercise resulted in a faster VO2 pulmonary kinetics response (τ1 = 13.41±3.96 s), an improved performance in the time to exhaustion (238.8±50.2 s) and similar blood lactate concentrations ([La(-)]) values (11.8±1.7 mmol.L(-1)) compared to the condition without prior exercise (16.0±5.56 s, 215.3±60.1 s and 10.7±1.2 mmol.L(-1), for τ1, time sustained at VO2max and [La(-)], respectively). Performance of prior heavy exercise, although useful in accelerating the VO2 pulmonary kinetics response during a subsequent time to exhaustion exercise (τ1 = 9.18±1.60 s), resulted in a shorter time sustained at VO2max (155.5±46.0 s), while [La(-)] was similar (13.5±1.7 mmol.L(-1)) compared to the other two conditions. Although both prior moderate and heavy exercise resulted in a faster pulmonary VO2 kinetics response, only prior moderate exercise lead to improved rowing performance.

  3. Single session of sprint interval training elicits similar cardiac output but lower oxygen uptake versus ramp exercise to exhaustion in men and women

    Science.gov (United States)

    Horn, Trevor; Roverud, Garret; Sutzko, Kandice; Browne, Melissa; Parra, Cristina; Astorino, Todd A

    2016-01-01

    Sprint interval training (SIT) elicits comparable long-term adaptations versus continuous exercise training (CEX) including increased maximal oxygen uptake (VO2max) and fat utilization. However, there is limited research examining acute hemodynamic responses to SIT. The aim of this study was to examine hemodynamic responses to low-volume SIT. Active men (n=6, VO2max = 39.8 ± 1.7 mL/kg/min) and women (n=7, VO2max = 37.3 ± 5.7 mL/kg/min) performed a ramp-based VO2max test (RAMP) to determine workload for the SIT session. Subjects returned within 1 wk and completed a session of SIT consisting of six 30-s bouts of “all-out” cycling at 130% maximal workload (Wmax) interspersed with 120 s of active recovery. Continuously during RAMP and exercise and recovery in SIT, VO2 was obtained and thoracic impedance was used to estimate heart rate (HR), stroke volume (SV), and cardiac output (CO). Results revealed no significant differences in COmax (p = 0.12, 19.7 ± 2.4 L/min vs. 20.3 ± 1.8 L/min) but lower SVmax (p = 0.004, 110.4 ± 15.7 mL vs. 119.4 ± 15.5 mL) in RAMP versus SIT. HRmax from SIT (179.0 ± 11.8 b/min) was lower (p = 0.008) versus RAMP (184.4 ± 7.9 b/min). Peak VO2 (L/min) was lower (p Sprint interval training consisting of 3 min of supramaximal exercise elicits similar CO yet lower VO2 compared to RAMP.

  4. Optimizing strength training for running and cycling endurance performance: A review.

    Science.gov (United States)

    Rønnestad, B R; Mujika, I

    2014-08-01

    Here we report on the effect of combining endurance training with heavy or explosive strength training on endurance performance in endurance-trained runners and cyclists. Running economy is improved by performing combined endurance training with either heavy or explosive strength training. However, heavy strength training is recommended for improving cycling economy. Equivocal findings exist regarding the effects on power output or velocity at the lactate threshold. Concurrent endurance and heavy strength training can increase running speed and power output at VO2max (Vmax and Wmax, respectively) or time to exhaustion at Vmax and Wmax. Combining endurance training with either explosive or heavy strength training can improve running performance, while there is most compelling evidence of an additive effect on cycling performance when heavy strength training is used. It is suggested that the improved endurance performance may relate to delayed activation of less efficient type II fibers, improved neuromuscular efficiency, conversion of fast-twitch type IIX fibers into more fatigue-resistant type IIA fibers, or improved musculo-tendinous stiffness.

  5. Effects of the rotor pedalling system on the performance of trained cyclists during incremental and constant-load cycle-ergometer tests.

    Science.gov (United States)

    Lucía, A; Balmer, J; Davison, R C R; Pérez, M; Santalla, A; Smith, P M

    2004-10-01

    The aim of this study was to determine the effects of Rotor, a new cycle crank configuration that effectively allows the pedals to move independently throughout the duty cycle, on indices of endurance cycling performance in trained cyclists. Ten cyclists (5 Rotor users and 5 non-users; age (mean +/- SD): 22 +/- 5 y; VO(2)max: 69.5 +/- 5.1 mL. kg(-1).min(-1)) volunteered to participate in the study. On four separate days, the subjects performed four cycle-ergometer tests, i.e. two incremental tests and two 20-min tests. An imposed crank rate of 75 rev.min(-1) was used during all tests. The incremental protocol started at 112.5 W, and the power output was increased by 37.5 W every 3 min until volitional exhaustion. The 20-min tests were performed at a fixed power output equivalent to 80 % of the highest power output that the cyclists maintained for a complete 3-min period during incremental tests. Both types of tests were performed with the conventional crank system and the Rotor following a counter-balanced, cross-over design. Gas exchange parameters were measured in all the tests and blood lactate was determined at the end of each 3-min period (incremental tests) and at the end of the 20-min tests. A three factor (pedalling system used during the tests x habitual pedalling system x power output [incremental tests] or time [20-min tests]) ANOVA with repeated measures on power output (incremental tests) or time (20-min tests) was used to analyse several indices of performance, e.g. peak power output, VO(2)max, lactate threshold, onset of blood lactate accumulation, economy, delta, and gross efficiency. No differences (p > 0.05) were found between the Rotor and conventional systems for any of the aforementioned variables. It seems that the theoretical advantage brought about by the Rotor system, i.e. improved contra-lateral cooperation of both legs, would be minimized in trained cyclists. Although field studies are needed to assess the possible implications, in terms

  6. Monitoring Perceived Stress and Recovery in Relation to Cycling Performance in Female Athletes

    NARCIS (Netherlands)

    Otter, R T A; Brink, M S; van der Does, H T D; Lemmink, K A P M

    2015-01-01

    The purpose was to investigate perceived stress and recovery related to cycling performance of female athletes over one full year. 20 female athletes (age, 27±8 years; ˙VO2max, 50.3±4.6 mL·kg(-1)·min(-1)) were measured 8 times in one year to determine perceived stress and recovery (RESTQ-Sport) in r

  7. Improving Cycling Performance: Transcranial Direct Current Stimulation Increases Time to Exhaustion in Cycling.

    Directory of Open Access Journals (Sweden)

    Marcelo Vitor-Costa

    Full Text Available The central nervous system seems to have an important role in fatigue and exercise tolerance. Novel noninvasive techniques of neuromodulation can provide insights on the relationship between brain function and exercise performance. The purpose of this study was to determine the effects of transcranial direct current stimulation (tDCS on physical performance and physiological and perceptual variables with regard to fatigue and exercise tolerance. Eleven physically active subjects participated in an incremental test on a cycle simulator to define peak power output. During 3 visits, the subjects experienced 3 stimulation conditions (anodal, cathodal, or sham tDCS-with an interval of at least 48 h between conditions in a randomized, counterbalanced order to measure the effects of tDCS on time to exhaustion at 80% of peak power. Stimulation was administered before each test over 13 min at a current intensity of 2.0 mA. In each session, the Brunel Mood State questionnaire was given twice: after stimulation and after the time-to-exhaustion test. Further, during the tests, the electromyographic activity of the vastus lateralis and rectus femoris muscles, perceived exertion, and heart rate were recorded. RM-ANOVA showed that the subjects performed better during anodal primary motor cortex stimulation (491 ± 100 s compared with cathodal stimulation (443 ± 11 s and sham (407 ± 69 s. No significant difference was observed between the cathodal and sham conditions. The effect sizes confirmed the greater effect of anodal M1 tDCS (anodal x cathodal = 0.47; anodal x sham = 0.77; and cathodal x sham = 0.29. Magnitude-based inference suggested the anodal condition to be positive versus the cathodal and sham conditions. There were no differences among the three stimulation conditions in RPE (p = 0.07 or heart rate (p = 0.73. However, as hypothesized, RM- ANOVA revealed a main effect of time for the two variables (RPE and HR: p < 0.001. EMG activity also did not

  8. Preexercise high and low glycemic index meals and cycling performance in untrained females: randomized, cross-over trial of efficacy.

    Science.gov (United States)

    Moore, Laura; Szpalek, Hannah M; McNaughton, Lars R

    2013-01-01

    This study examined the effects of high and low glycemic index (GI) carbohydrate preexercise meals (2.5 g CHO/kg body mass) on cycle performance in untrained females. Ten females, cycled at 60% VO(2 max) to exhaustion, on two occasions. After fasting, subjects ate an isocaloric, high glycemic index (HGI)/low glycemic index (LGI) meal in a random order. Blood samples were taken at rest/postprandial/during and after exercise and blood glucose and lactate were measured. Ingestion of the LGI meal resulted in a performance time of 67.4 ± 8.4 min versus an HGI time of 48.9 ± 10.0 min (p = 0.02). Fifteen minutes after the HGI meal there was a significant increase (p < 0.001) in glucose levels, which was not seen in the LGI trial. Twenty minutes into the HGI exercise trial, there was a large decline in blood glucose concentration beyond resting levels. Based on this work, we found that untrained female participants should utilize LGI meals preexercise for endurance activities rather than HGI meals.

  9. A SYSTEMATIC REVIEW AND META-ANALYSIS COMPARING CARDIOPULMONARY EXERCISE TEST VALUES OBTAINED FROM THE ARM CYCLE AND THE LEG CYCLE RESPECTIVELY IN HEALTHY ADULTS

    Science.gov (United States)

    Christensen, Jan; Tang, Lars Hermann; Keller, Camilla; Doherty, Patrick; Zwisler, Ann-Dorthe; Taylor, Rod S; Langberg, Henning

    2016-01-01

    Introduction The cardiopulmonary exercise test (CPET) assesses maximal oxygen uptake (VO2max) and is commonly performed on a leg cycle ergometer (LC). However, some individuals would rather perform the CPET on an arm cycle ergometer (AC). Objective The objectives of this study were to undertake a systematic review and meta-analysis of the difference in VO2max achieved by AC compared to LC in healthy adults and to explore factors that may be predictive of this difference. Methods MEDLINE, EMBASE, CINAHL, and PEDro were searched in April 2015. The differences in VO2max (ACLCdiff) were pooled across studies using random effects meta-analysis and three different methods were used to estimate the ratio between the values obtained from the tests (ACLCratio). Results This paper included 41 studies with a total of 581 participants. The mean ACLCdiff across studies was 12.5 ml/kg/min and 0.89 l/min with a mean ACLCratio of 0.70. The ACLCdiff was lower in studies with higher mean age and lower aerobic capacity. Conclusion There is linear association between the AC and LC values in healthy adults. The AC values were on average 70% of the LC values. The magnitude of this difference appeared to be reduced in studies on older and less active populations. Level of evidence 3a PMID:27999717

  10. The training stimulus experienced by the leg muscles during cycling in humans.

    Science.gov (United States)

    McPhee, Jamie S; Williams, Alun G; Stewart, Claire; Baar, Keith; Schindler, Joaquin Perez; Aldred, Sarah; Maffulli, Nicola; Sargeant, Anthony J; Jones, David A

    2009-06-01

    Considerable variability exists between people in their health- and performance-related adaptations to conventional endurance training. We hypothesized that some of this variability might be due to differences in the training stimulus received by the working muscles. In 71 young sedentary women we observed large variations in the ratio of one-leg cycling muscle aerobic capacity (V(O2peak)) to two-leg cycling whole-body maximal oxygen uptake (V(O2max); Ratio(1:2); range 0.58-0.96). The variability in Ratio(1:2) was primarily due to differences between people in one-leg V(O2peak) (r = 0.71, P < 0.0005) and was not related to two-leg V(O2max) (r = 0.15, P = 0.209). Magnetic resonance imaging (n = 30) and muscle biopsy sampling (n = 20) revealed that one-leg V(O2peak) was mainly determined by muscle volume (r = 0.73, P < 0.0005) rather than muscle fibre type or oxidative capacity. A high one-leg V(O2peak) was associated with favourable lipoprotein profiles (P = 0.033, n = 24) but this was not the case for two-leg V(O2max). Calculations based on these data suggest that conventional two-leg exercise at 70% V(O2max) requires subjects with the lowest Ratio(1:2) to work their legs at 60% of single-leg V(O2peak), whilst those with the highest Ratio(1:2) work their legs at only 36% of maximum. It was concluded that endurance training carried out according to current guidelines will result in highly variable training stimuli for the leg muscles and variable magnitudes of adaptation. These conclusions have implications for the prescription of exercise to improve health and for investigations into the genetic basis of muscle adaptations.

  11. Validity of the revised Ekblom Bak cycle ergometer test in adults

    OpenAIRE

    Björkman, Frida; Ekblom-Bak, Elin; Ekblom, Örjan; Ekblom, Björn

    2016-01-01

    Purpose To further develop the Ekblom Bak-test prediction equation for estimation of VO2max from submaximal cycle ergometry. Methods The model group (117 men and 100 women, aged 48.3 ± 15.7 and 46.1 ± 16.8 years, VO2max 46.6 ± 11.1 and 40.4 ± 9.6 mL kg−1 min−1, respectively) and the cross-validation group (60 men and 55 women, aged 40.6 ± 17.1 and 41.6 ± 16.7 years, VO2max 49.0 ± 12.1 and 43.2 ± 8.9 mL min−1 kg−1, respectively) performed 4 min of cycling on a standard work rate (30 W) directl...

  12. The effect of β-alanine supplementation on cycling time trials of different length.

    Science.gov (United States)

    Bellinger, Phillip M; Minahan, Clare L

    2016-10-01

    The varying results reported in response to β-alanine supplementation may be related to the duration and nature of the exercise protocol employed. We investigated the effects of β-alanine supplementation on a wide range of cycling performance tests in order to produce a clear concise set of criteria for its efficacy. Fourteen trained cyclists (Age = 24.8 ± 6.7 years; VO2max = 65.4 ± 10.2 mL·kg·min(-1)) participated in this placebo-controlled, double-blind study. Prior to supplementation, subjects completed two (familiarization and baseline) supramaximal cycling bouts until exhaustion (120% pre-supplementation VO2max) and two 1-, 4- and 10-km cycling time trial (TT). Subjects then supplemented orally for 4 weeks with 6.4 g/d placebo or β-alanine and repeated the battery of performance tests. Blood lactate was measured pre-exercise, post-exercise and 5  min post-exercise. β-alanine supplementation elicited significant increases in time to exhaustion (TTE) (17.6 ± 11.5 s; p = 0.013, effect compared with placebo) and was likely to be beneficial to 4-km TT performance time (-7.8 ± 8.1 s; 94% likelihood), despite not being statistically different (p = 0.060). Performance times in the 1- and 10-km TT were not affected by treatment. For the highly trained cyclists in the current study, β-alanine supplementation significantly extended supramaximal cycling TTE and may have provided a worthwhile improvement to 4-km TT performance. However, 1- and 10-km cycling TT performance appears to be unaffected by β-alanine supplementation.

  13. Intravenous bicarbonate and sodium chloride both prolong endurance during intense cycle ergometer exercise.

    Science.gov (United States)

    Mitchell, T H; Abraham, G; Wing, S; Magder, S A; Cosio, M G; Deschamps, A; Marliss, E B

    1990-08-01

    To determine the effects of neutralizing exercise systemic acidosis via the intravenous route upon endurance and metabolic responses, eight lean, normal, postabsorptive men exercised to exhaustion at about 80% of their VO2 max (69 +/- 3%, mean +/- SEM, of maximum power output) on a cycle ergometer. Exercise studies were performed either with no infusion (control) or with a total infusion volume of about 1.5 L, mainly as 1.3% sodium bicarbonate or as 0.9% sodium chloride (NaCl), infused (double-blind) throughout exercise. The sodium bicarbonate was to prevent acid-base change, the sodium chloride was as a control for the volume infused. Arterialized venous blood and breath-by-breath analysis of expired gases were obtained. [H+] (nmol.L-1) and [HCO3-] (mmol.L-1) at exhaustion were similar in control and NaCl (46.5 +/- 1.8, 19.9 +/- 0.9), but remained unchanged from rest values with bicarbonate (38.4 +/- 0.9, 24.8 +/- 1.5, p less than 0.005 vs control and NaCl). At exhaustion, VO2, VCO2, RER, heart rate, and systolic BP as well as FFA, glycerol, alanine, insulin, norepinephrine, and epinephrine did not differ among protocols. Endurance was markedly prolonged (p less than 0.01) with bicarbonate (31.9 +/- 5.8 min) and NaCl (31.8 +/- 4.1 min) compared with the control (19.0 +/- 2.9 min) condition. Plasma glucose at exhaustion was higher (p less than 0.025) in the control compared to bicarbonate and NaCl experiments, while lactate was higher (p less than 0.025) in the bicarbonate than in the control and NaCl experiments. Thus, the prolonged endurance with sodium bicarbonate infusion could not be explained either by its effect of maintaining blood acid-base equilibrium or concomitant metabolic changes.

  14. Aerobic and anaerobic power characteristics of competitive cyclists in the United States Cycling Federation.

    Science.gov (United States)

    Tanaka, H; Bassett, D R; Swensen, T C; Sampedro, R M

    1993-08-01

    The purpose of this study was to characterize the aerobic and anaerobic capabilities of United States Cycling Federation cyclists in different categories. To determine aerobic and anaerobic power, 38 competitive road cyclists (32 males, 6 females) performed a VO2max test and a Wingate anaerobic test, respectively. Male cyclists in category II had the highest VO2max, both in absolute and relative terms. Their VO2max was 6% and 10% higher than category III and IV cyclists, respectively (4.98 +/- 0.14 vs 4.72 +/- 0.15 vs 4.54 +/- 0.12 l/min). A significant difference existed between category II and IV male cyclists (p < 0.05). VO2max for female cyclists (3.37 +/- 0.13 l/min) was significantly (p < 0.05) lower than those for males. The Wingate anaerobic test revealed that male cyclists in category II also had the highest anaerobic power output. The peak power output in category II, III and IV was 13.86 +/- 0.23, 13.55 +/- 0.25, and 12.80 +/- 0.41 W/kg, respectively. The mean power output in category II, III, and IV was 11.22 +/- 0.18, 11.06 +/- 0.15, and 10.40 +/- 0.30 W/kg, respectively. The difference in the mean power output between category II and IV was significant (p < 0.05). Female cyclists recorded significantly less peak and mean power output than their male counterparts (p < 0.05). However, when expressed relative to lean body mass, anaerobic power was similar for both sexes. No inter-correlation was found in any measurement between the aerobic and anaerobic power values. On the whole, category II male cyclists were characterized by higher aerobic and anaerobic power outputs.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Influence of blood donation on oxygen uptake kinetics during moderate and heavy intensity cycle exercise.

    Science.gov (United States)

    Gordon, D; Marshall, K; Connell, A; Barnes, R J

    2010-05-01

    The purpose of this study was to determine the effects of a reduced whole body blood volume on the kinetic response of VO(2) during moderate and heavy intensity exercise. Six males and four females (age, 21+/-2 yrs; height, 175.2+/-5.1 cm; weight, 66.4+/-2.8 kg; VO(2)max, 53.0+/-4.1 ml x kg (-1) x min(-1)), completed a square-wave cycling ramp test to determine ventilatory threshold (VT) and VO(2max). Kinetics trials were completed 24 h pre and post donation of 450 cm (3) of blood. The kinetics trials were moderate intensity (80%VT) and heavy intensity (Delta50% VT - VO(2max)). Breath-by-breath gas exchange, heart rate, blood pressure, haemoglobin O(2) saturation, and blood [lactate] were measured throughout the trials. Post-donation haemoglobin, haematocrit and erythrocyte count were all significantly reduced (por= 0.05), or in the amplitude of the slow component. The capacity of the cardiovascular system to meet the metabolic demands of skeletal muscle at the onset of exercise does not limit the oxygen uptake.

  16. The Athlete’s Brain: Cross-Sectional Evidence for Neural Efficiency during Cycling Exercise

    Directory of Open Access Journals (Sweden)

    Sebastian Ludyga

    2016-01-01

    Full Text Available The “neural efficiency” hypothesis suggests that experts are characterized by a more efficient cortical function in cognitive tests. Although this hypothesis has been extended to a variety of movement-related tasks within the last years, it is unclear whether or not neural efficiency is present in cyclists performing endurance exercise. Therefore, this study examined brain cortical activity at rest and during exercise between cyclists of higher (HIGH; n=14; 55.6 ± 2.8 mL/min/kg and lower (LOW; n=15; 46.4 ± 4.1 mL/min/kg maximal oxygen consumption (VO2MAX. Male and female participants performed a graded exercise test with spirometry to assess VO2MAX. After 3 to 5 days, EEG was recorded at rest with eyes closed and during cycling at the individual anaerobic threshold over a 30 min period. Possible differences in alpha/beta ratio as well as alpha and beta power were investigated at frontal, central, and parietal sites. The statistical analysis revealed significant differences between groups (F=12.04; p=0.002, as the alpha/beta ratio was increased in HIGH compared to LOW in both the resting state (p≤0.018 and the exercise condition (p≤0.025. The present results indicate enhanced neural efficiency in subjects with high VO2MAX, possibly due to the inhibition of task-irrelevant cognitive processes.

  17. The Athlete's Brain: Cross-Sectional Evidence for Neural Efficiency during Cycling Exercise.

    Science.gov (United States)

    Ludyga, Sebastian; Gronwald, Thomas; Hottenrott, Kuno

    2016-01-01

    The "neural efficiency" hypothesis suggests that experts are characterized by a more efficient cortical function in cognitive tests. Although this hypothesis has been extended to a variety of movement-related tasks within the last years, it is unclear whether or not neural efficiency is present in cyclists performing endurance exercise. Therefore, this study examined brain cortical activity at rest and during exercise between cyclists of higher (HIGH; n = 14; 55.6 ± 2.8 mL/min/kg) and lower (LOW; n = 15; 46.4 ± 4.1 mL/min/kg) maximal oxygen consumption (VO2MAX). Male and female participants performed a graded exercise test with spirometry to assess VO2MAX. After 3 to 5 days, EEG was recorded at rest with eyes closed and during cycling at the individual anaerobic threshold over a 30 min period. Possible differences in alpha/beta ratio as well as alpha and beta power were investigated at frontal, central, and parietal sites. The statistical analysis revealed significant differences between groups (F = 12.04; p = 0.002), as the alpha/beta ratio was increased in HIGH compared to LOW in both the resting state (p ≤ 0.018) and the exercise condition (p ≤ 0.025). The present results indicate enhanced neural efficiency in subjects with high VO2MAX, possibly due to the inhibition of task-irrelevant cognitive processes.

  18. Oxygen uptake in water polo, comparison and agreement in cycle ergometer and eggbeater kick: A pilot study

    Directory of Open Access Journals (Sweden)

    Ligia Ignêz Engelmann

    Full Text Available Abstract The aim of this study was to compare and verify the agreement of maximal oxygen uptake (VO2 max values obtained from tests on land and in water. Twelve recreational water polo players (30.5 ± 7.7 years; 79.2 ± 7.2 kg body mass; 179.1 ± 5.9 cm height were assessed in two phases: (1 in laboratory with maximal test on a cycle ergometer and (2 in a swimming pool with maximal test in eggbeater kick. Maximum values obtained in the two tests (respectively, cycle ergometer, and eggbeater kick: VO2 max = 40.2 ± 2.7 ml.kg-1.min-1 and 38.4 ± 5.7 ml.kg-1.min-1; RER = 1.17 ± 0.08 and 1.19 ± 0.12; HR max = 181.4 ± 11.7 bpm and 179 ± 11.7 bpm; IEP = 20 and 20 did not show significant differences. According to the Bland-Altman analyses, there were acceptable limits of agreement between the two tests (land and water. Therefore, it can be concluded that the eggbeater kick test is a specific and valid protocol to asses VO2 max in water polo players.

  19. Simulation of CO2 Brayton Cycle for Engine Exhaust Heat Recovery under Various Operating Loads

    Institute of Scientific and Technical Information of China (English)

    舒歌群; 张承宇; 田华; 高媛媛; 李团兵; 仇荣赓

    2015-01-01

    A bottoming cycle system based on CO2 Brayton cycle is proposed to recover the engine exhaust heat. Its performance is compared with the conventional air Brayton cycle under five typical engine conditions. The results show that CO2 Brayton cycle proves to be superior to the air Brayton cycle in terms of the system net output power, thermal efficiency and recovery efficiency. In most cases, the recovery efficiency of CO2 Brayton cycle can be higher than 9%and the system has a better performance at the engine’s high operating load. The thermal efficiency can be as large as 24.83%under 100%operating load, accordingly, the net output power of 14.86 kW is obtained.

  20. Influence of driving cycles on exhaust emissions and fuel consumption of gasoline passenger car in Bangkok.

    Science.gov (United States)

    Nutramon, Tamsanya; Supachart, Chungpaibulpatana

    2009-01-01

    The influence of different driving cycles on their exhaust emissions and fuel consumption rate of gasoline passenger car was investigated in Bangkok based on the actual measurements obtained from a test vehicle driving on a standard chassis dynamometer. A newly established Bangkok driving cycle (BDC) and the European driving cycle (EDC) which is presently adopted as the legislative cycle for testing automobiles registered in Thailand were used. The newly developed BDC is constructed using the driving characteristic data obtained from the real on-road driving tests along selected traffic routes. A method for selecting appropriate road routes for real driving tests is also introduced. Variations of keyed driving parameters of BDC with different driving cycles were discussed. The results showed that the HC and CO emission factors of BDC are almost two and four times greater than those of EDC, respectively. Although the difference in the NOx emission factor is small, the value from BDC is still greater than that of EDC by 10%. Under BDC, the test vehicle consumes fuel about 25% more than it does under EDC. All these differences are mainly attributed to the greater proportion of idle periods and higher fluctuations of vehicle speed in the BDC cycle. This result indicated that the exhausted emissions and fuel consumption of vehicles obtained from tests under the legislative modal-type driving cycle (EDC) are significantly different from those actually produced under real traffic conditions especially during peak periods.

  1. Influence of driving cycles on exhaust emissions and fuel consumption of gasoline passenger car in Bangkok

    Institute of Scientific and Technical Information of China (English)

    NUTRAMON Tamsanya; SUPACHART Chungpaibulpatana

    2009-01-01

    The influence of different driving cycles on their exhaust emissions and fuel consumption rate of gasoline passenger car was investigated in Bangkok based on the actual measurements obtained from a test vehicle driving on a standard chassis dynamometer. A newly established Bangkok driving cycle (BDC) and the European driving cycle (EDC) which is presently adopted as the legislative cycle for testing automobiles registered in Thailand were used. The newly developed BDC is constructed using the driving characteristic data obtained from the real on-road driving tests along selected traffic routes. A method for selecting appropriate road routes for real driving tests is also introduced. Variations of keyed driving parameters of BDC with different driving cycles were discussed. The results showed that the HC and CO emission factors of BDC are almost two and four times greater than those of EDC, respectively. Although the difference in the NOx emission factor is small, the value from BDC is still greater than that of EDC by 10%. Under BDC, the test vehicle consumes fuel about 25% more than it does under EDC. All these differences are mainly attributed to the greater proportion of idle periods and higher fluctuations of vehicle speed in the BDC cycle. This result indicated that the exhausted emissions and fuel consumption of vehicles obtained from tests under the legislative modal-type driving cycle (EDC) are significantly different from those actually produced under real traffic conditions especially during peak periods.

  2. Mathematical modelling and reactor design for multi-cycle bioregeneration of nitrate exhausted ion exchange resin.

    Science.gov (United States)

    Ebrahimi, Shelir; Roberts, Deborah J

    2016-01-01

    Nitrate contamination is one of the largest issues facing communities worldwide. One of the most common methods for nitrate removal from water is ion exchange using nitrate selective resin. Although these resins have a great capacity for nitrate removal, they are considered non regenerable. The sustainability of nitrate-contaminated water treatment processes can be achieved by regenerating the exhausted resin several times rather than replacing and incineration of exhausted resin. The use of multi-cycle exhaustion/bioregeneration of resin enclosed in a membrane has been shown to be an effective and innovative regeneration method. In this research, the mechanisms for bioregeneration of resin were studied and a mathematical model which incorporated physical desorption process with biological removal kinetics was developed. Regardless of the salt concentration of the solution, this specific resin is a pore-diffusion controlled process (XδD ¯CDr0(5+2α)3) shows that the bioregeneration process is controlled by reaction kinetics and is governed by biological removal of nitrate. The model was validated by comparison to experimental data; the average of R-squared values for cycle 1 to 5 of regeneration was 0.94 ± 0.06 which shows that the developed model predicted the experimental results very well. The model sensitivity for different parameters was evaluated and a model bioreactor design for bioregeneration of highly selective resins was also presented.

  3. Analysis of a Temperature-Controlled Exhaust Thermoelectric Generator During a Driving Cycle

    Science.gov (United States)

    Brito, F. P.; Alves, A.; Pires, J. M.; Martins, L. B.; Martins, J.; Oliveira, J.; Teixeira, J.; Goncalves, L. M.; Hall, M. J.

    2016-03-01

    Thermoelectric generators can be used in automotive exhaust energy recovery. As car engines operate under wide variable loads, it is a challenge to design a system for operating efficiently under these variable conditions. This means being able to avoid excessive thermal dilution under low engine loads and being able to operate under high load, high temperature events without the need to deflect the exhaust gases with bypass systems. The authors have previously proposed a thermoelectric generator (TEG) concept with temperature control based on the operating principle of the variable conductance heat pipe/thermosiphon. This strategy allows the TEG modules’ hot face to work under constant, optimized temperature. The variable engine load will only affect the number of modules exposed to the heat source, not the heat transfer temperature. This prevents module overheating under high engine loads and avoids thermal dilution under low engine loads. The present work assesses the merit of the aforementioned approach by analysing the generator output during driving cycles simulated with an energy model of a light vehicle. For the baseline evaporator and condenser configuration, the driving cycle averaged electrical power outputs were approximately 320 W and 550 W for the type-approval Worldwide harmonized light vehicles test procedure Class 3 driving cycle and for a real-world highway driving cycle, respectively.

  4. Effect of Gas Turbine Exhaust Temperature, Stack Temperature and Ambient Temperature on Overall Efficiency of Combine Cycle Power Plant

    OpenAIRE

    Khan, M N; K.P.Tyagi

    2010-01-01

    The gas turbine exhaust temperature, stack temperature and ambient temperature play a very important role during the predication of the performance of combine cycle power plant. This paper covers parametric analysis of effects of gas turbine exhaust temperature, stack temperature and ambient temperature on the overall efficiency of combine cycle power plant keeping the gas turbine efficiency as well as steam turbine efficiency constant. The results shows that out of three variables i.e. turbi...

  5. Brayton cycle for internal combustion engine exhaust gas waste heat recovery

    Directory of Open Access Journals (Sweden)

    J Galindo

    2015-06-01

    Full Text Available An average passenger car engine effectively uses about one-third of the fuel combustion energy, while the two-thirds are wasted through exhaust gases and engine cooling. It is of great interest to automotive industry to recover some of this wasted energy, thus increasing the engine efficiency and lowering fuel consumption and contamination. Waste heat recovery for internal combustion engine exhaust gases using Brayton cycle machine was investigated. The principle problems of application of such a system in a passenger car were considered: compressor and expander machine selection, machine size for packaging under the hood, efficiency of the cycle, and improvement of engine efficiency. Important parameters of machines design have been determined and analyzed. An average 2-L turbocharged gasoline engine’s New European Driving Cycle points were taken as inlet points for waste heat recovery system. It is theoretically estimated that the recuperated power of 1515 W can be achieved along with 5.7% improvement in engine efficiency, at the point where engine power is 26550 W.

  6. Optimization of Low-Temperature Exhaust Gas Waste Heat Fueled Organic Rankine Cycle

    Institute of Scientific and Technical Information of China (English)

    WANGHui—tao; WANGHua; ZHANGZhu—ming

    2012-01-01

    Low temperature exhaust gases carrying large amount of waste heat are released by steel-making process and many other industries, Organic Rankine Cycles (ORCs) are proven to be the most promising technology to re- cover the low-temperature waste heat, thereby to get more financial benefits for these industries. The exergy analysis of ORC units driven by low-temperature exhaust gas waste heat and charged with dry and isentropic fluid was per- formed, and an intuitive approach with simple impressions was developed to calculate the performances of the ORC unit. Parameter optimization was conducted with turbine inlet temperature simplified as the variable and exergy effi- ciency or power output as the objective function by means of Penalty Function and Golden Section Searching algo- rithm based on the formulation of the optimization problem. The power generated by the optimized ORC unit can be nearly as twice as that generated by a non-optimized ORC unit. In addition, cycle parametric analysis was performed to examine the effects of thermodynamic parameters on the cycle performances such as thermal efficiency and exergy efficiency. It is proven that performance of ORC unit is mainly affected by the thermodynamic property of working fluid, the waste heat temperature, the pinch point temperature of the evaporator, the specific heat capacity of the heat carrier and the turbine inlet temperature under a given environment temperature.

  7. Development of an Organic Rankine Cycle system for exhaust energy recovery in internal combustion engines

    Science.gov (United States)

    Cipollone, Roberto; Bianchi, Giuseppe; Gualtieri, Angelo; Di Battista, Davide; Mauriello, Marco; Fatigati, Fabio

    2015-11-01

    Road transportation is currently one of the most influencing sectors for global energy consumptions and CO2 emissions. Nevertheless, more than one third of the fuel energy supplied to internal combustion engines is still rejected to the environment as thermal waste at the exhaust. Therefore, a greater fuel economy might be achieved recovering the energy from exhaust gases and converting it into useful power on board. In the current research activity, an ORC-based energy recovery system was developed and coupled with a diesel engine. The innovative feature of the recovery power unit relies upon the usage of sliding vane rotary machines as pump and expander. After a preliminary exhaust gas mapping, which allowed to assess the magnitude of the thermal power to be recovered, a thermodynamic analysis was carried out to design the ORC system and the sliding vane machines using R236fa as working fluid. An experimental campaign was eventually performed at different operating regimes according to the ESC procedure and investigated the recovery potential of the power unit at design and off-design conditions. Mechanical power recovered ranged from 0.7 kW up to 1.9 kW, with an overall cycle efficiency from 3.8% up to 4.8% respectively. These results candidate sliding vane machines as efficient and reliable devices for waste heat recovery applications.

  8. Incremental effects of 28 days of beta-alanine supplementation on high-intensity cycling performance and blood lactate in masters female cyclists.

    Science.gov (United States)

    Glenn, J M; Gray, M; Stewart, R; Moyen, N E; Kavouras, S A; DiBrezzo, R; Turner, R; Baum, J

    2015-12-01

    Within the aging population, there exists a subset of individuals termed masters athletes (MA). As masters-level competition increases in popularity, MA must find methods to enhance individual athletic performance. Longitudinal beta-alanine (BA) supplementation is suggested to enhance physical capability during exercise; however, these effects have not been evaluated in MA. To examine the longitudinal effects of BA on time to exhaustion (TTE), total work completed (TWC), and lactate clearance in female MA cyclists. Twenty-two female MA (age = 53.3 ± 1.0) participated in this double-blind design. Subjects were randomly assigned to BA (n = 11; 800 mg BA + 8 g dextrose) or placebo (PLA; n = 11; 8 g dextrose) groups and supplemented 4 doses/day over 28 days. Every 7 days, subjects completed a cycling TTE at 120% VO2max, and TWC was calculated. Blood lactate was measured at baseline, immediate post, and 20-min post each TTE. No significant differences existed between groups for any variable at baseline (p > 0.05). After 28 days supplementation, BA had greater TTE (23 vs 1% change) and TWC (21 vs 2% change) than PLA (p < 0.05). Following the 20-min TTE recovery, lactate was 24% lower in BA compared to PLA (4.35 vs. 5.76 mmol/L, respectively). No differences existed for variables during intermittent weeks. 28 days of BA supplementation increased cycling performance via an enhanced time to exhaustion and total work completed with associated lactate clearance during passive rest in female MA.

  9. Caffeine Affects Time to Exhaustion and Substrate Oxidation during Cycling at Maximal Lactate Steady State

    Directory of Open Access Journals (Sweden)

    Rogério Santos de Oliveira Cruz

    2015-06-01

    Full Text Available This study analyzed the effects of caffeine intake on whole-body substrate metabolism and exercise tolerance during cycling by using a more individualized intensity for merging the subjects into homogeneous metabolic responses (the workload associated with the maximal lactate steady state—MLSS. MLSS was firstly determined in eight active males (25 ± 4 years, 176 ± 7 cm, 77 ± 11 kg using from two to four constant-load tests of 30 min. On two following occasions, participants performed a test until exhaustion at the MLSS workload 1 h after taking either 6 mg/kg of body mass of caffeine or placebo (dextrose, in a randomized, double-blinded manner. Respiratory exchange ratio was calculated from gas exchange measurements. There was an improvement of 22.7% in time to exhaustion at MLSS workload following caffeine ingestion (95% confidence limits of ±10.3%, p = 0.002, which was accompanied by decrease in respiratory exchange ratio (p = 0.001. These results reinforce findings indicating that sparing of the endogenous carbohydrate stores could be one of the several physiological effects of caffeine during submaximal performance around 1 h.

  10. Reciprocating Expander for an Exhaust Heat Recovery Rankine Cycle for a Passenger Car Application

    Directory of Open Access Journals (Sweden)

    Osoko Shonda

    2012-06-01

    Full Text Available Nowadays, on average, two thirds of the fuel energy consumed by an engine is wasted through the exhaust gases and the cooling liquid. The recovery of this energy would enable a substantial reduction in fuel consumption. One solution is to integrate a heat recovery system based on a steam Rankine cycle. The key component in such a system is the expander, which has a strong impact on the system’s performance. A survey of different expander technologies leads us to select the reciprocating expander as the most promising one for an automotive application. This paper therefore proposes a steady-state semi-empirical model of the expander device developed under the Engineering Equation Solver (EES environment. The ambient and mechanical losses as well as internal leakage were taken into account by the model. By exploiting the expander manufacturer’s data, all the parameters of the expander model were identified. The model computes the mass flow rate, the power output delivered and the exhaust enthalpy of the steam. The maximum deviation between predictions and measurement data is 4.7%. A performance study of the expander is carried out and shows that the isentropic efficiency is quite high and increases with the expander rotary speed. The mechanical efficiency depends on mechanical losses which are quite high, approximately 90%. The volumetric efficiency was also evaluated.

  11. Effect of air resistance on the metabolic cost and performance of cycling.

    Science.gov (United States)

    Davies, C T

    1980-01-01

    The metabolic cost (VO2) of cycling against a range of wind velocities (VW) was studied in a wind tunnel of 15 male cyclists and the results compared with work on a stationary cycle ergometer, uphill cycling on a treadmill, and performance times in road racing competitions. The results showed that VO2 at constant treadmill speed was proportional to V2W and was a linear function of work rate, both on the stationary ergometer and during uphill cycling on a motor driven treadmill. Maximal values of 5.04 1 x min-1 (69.3 ml x kg-1 x min-1) and 482 W were observed. The mean force (F) acting on the cyclists during the experiments in the wind tunnel was found to be equal to 0.0175 V2W x ms-1 (r = +0.98). The mean projected area (AP), drag areas (AD) and drag coefficient (CD) for the 15 cyclists were 0.50 m2, 0.280 m2, and 0.56 m2, respectively. During cycling out of doors on a calm day VO2 was calculated to be a curvilinear function of the cyclists' speed of progression (V). The best guide to the cyclists' maximal aerobic power output (VO2max) was given by their 16.1 km (10 mile) time: VO2max (1 x min-1) = -4.219 + 0.7727 V (ms-1) r = +0.89. The results suggested that the relative aerobic power output (% VO2max) which could be sustained for a given time by elite cyclists, is similar to that found previously for marathon athletes. However, due to the differences in the non-drag component of the work for given metabolic cost the cyclist will travel approx. 2 1/2 times the distance of an endurance athlete.

  12. New Zealand blackcurrant extract improves cycling performance and fat oxidation in cyclists.

    Science.gov (United States)

    Cook, Matthew David; Myers, Stephen David; Blacker, Sam David; Willems, Mark Elisabeth Theodorus

    2015-11-01

    Blackcurrant intake increases peripheral blood flow in humans, potentially by anthocyanin-induced vasodilation which may affect substrate delivery and exercise performance. We examined the effects of New Zealand blackcurrant (NZBC) extract on substrate oxidation, cycling time-trial performance and plasma lactate responses following the time-trial in trained cyclists. Using a randomized, double-blind, crossover design, 14 healthy men (age: 38 ± 13 years, height: 178 ± 4 cm, body mass: 77 ± 9 kg, VO2max: 53 ± 6 mL kg(-1) min(-1), mean ± SD) ingested NZBC extract (300 mg day(-1) CurraNZ™ containing 105 mg anthocyanin) or placebo (PL, 300 mg microcrystalline cellulose M102) for 7 days (washout 14 days). On day 7, participants performed 30 min of cycling (3 × 10 min at 45, 55 and 65 % VO2max), followed by a 16.1 km time-trial with lactate sampling during a 20-min passive recovery. NZBC extract increased fat oxidation at 65 % VO2max by 27 % (P < 0.05) and improved 16.1 km time-trial performance by 2.4 % (NZBC: 1678 ± 108 s, PL: 1722 ± 131 s, P < 0.05). Plasma lactate was higher with NZBC extract immediately following the time-trial (NZBC: 7.06 ± 1.73 mmol L(-1), PL: 5.92 ± 1.58 mmol L(-1), P < 0.01). Seven-day intake of New Zealand blackcurrant extract improves 16.1 km cycling time-trial performance and increases fat oxidation during moderate intensity cycling.

  13. Acute and prolonged reduction in joint stiffness in humans after exhausting stretch-shortening cycle exercise.

    Science.gov (United States)

    Kuitunen, S; Avela, J; Kyröläinen, H; Nicol, C; Komi, P V

    2002-11-01

    The purpose of the present study was to examine the acute and long-term fatigue effects of exhausting stretch-shortening cycle (SSC) exercise on the stiffness of ankle and knee joints. Five subjects were fatigued on a sledge apparatus by 100 maximal rebound jumps followed by continuous submaximal jumping until complete exhaustion. Neuromuscular fatigue effects were examined in submaximal hopping (HOP) and in maximal drop jumps (DJ) from 35 (DJ35) and 55 cm (DJ55) heights on a force plate. Additional force and reflex measurements were made using an ankle ergometer. Jumping tests and ankle ergometer tests were carried out before, immediately after, 2 h (2H), 2 days and 7 days (7D) after the SSC exercise. Kinematics, force and electromyography (EMG) recordings were complemented with inverse dynamics, which was used to calculate joint moments. The quotient of changes in joint moment divided by changes in joint angle was used as a value of joint stiffness (JS). In addition, blood lactate concentrations and serum creatine kinase activities were determined. The exercise induced a clear decrease in knee joint stiffness by [mean (SD)] 29 (13)% (P < 0.05) in HOP, 31 (6)% (P < 0.05) in DJ35 and 34 (14)% (P < 0.05) in DJ55. A similar trend was observed in the ankle joint stiffness with significant post-exercise reductions of 22 (8)% (P < 0.05) in DJ35 and of 27 (19)% (P < 0.05) at 2H in DJ55. The subsequent recovery of JS was slow and in some cases incomplete still at 7D. Generally, all the EMG parameters were fully recovered by 2H, whereas the force recovery was still incomplete at this time. These data indicate that the immediate reduction in JS was probably related to the effects of both central (neural) and peripheral (metabolic) fatigue, whereas the prolonged impairment was probably due to peripheral fatigue (muscle damage).

  14. Changes in the soleus muscle architecture after exhausting stretch-shortening cycle exercise in humans.

    Science.gov (United States)

    Ishikawa, M; Dousset, E; Avela, J; Kyröläinen, H; Kallio, J; Linnamo, V; Kuitunen, S; Nicol, C; Komi, P V

    2006-06-01

    This study focused on the architectural changes in the muscle-tendon complex during the immediate and secondary (delayed) reductions of performance (bimodal recovery) caused by an exhaustive rebound type stretch-shortening cycle (SSC) exercise. The isometric plantar flexor torque during maximum voluntary contraction (MVC) was measured together with recording of electromyography (EMG) and ultrasonography from the soleus muscle before (BEF), after (AFT), 2 h (2H), 2 and 8 days (2D, 8D) after the SSC exercise (n=8). The performance variables (MVC torque and EMG activation) followed the bimodal recovery patterns. This was not the case in the changes of the fascicle length and muscle thickness. The relative torque changes in MVC correlated positively (R=0.78, P=0.02) to the corresponding averaged EMG changes between BEF and 2H (BEF-->2H); the significance disappeared in the comparison between 2H and 2D (2H-->2D), during which period MVC showed a secondary reduction. The relative torque changes in MVC showed no correlation with the changes in muscle thickness between BEF-2H. However, this correlation between 2H-2D was negative (R=-0.85, PMVC increased at 2H, and then decreased more at 2D than 2H (PMVC could be related to the increase in muscle volume.

  15. An analytical study on the performance of the organic Rankine cycle for turbofan engine exhaust heat recovery

    Science.gov (United States)

    Saadon, S.; Abu Talib, A. R.

    2016-10-01

    Due to energy shortage and global warming, issues of energy saving have become more important. To increase the energy efficiency and reduce the fuel consumption, waste heat recovery is a significant method for energy saving. The organic Rankine cycle (ORC) has great potential to recover the waste heat from the core jet exhaust of a turbofan engine and use it to produce power. Preliminary study of the design concept and thermodynamic performance of this ORC system would assist researchers to predict the benefits of using the ORC system to extract the exhaust heat engine. In addition, a mathematical model of the heat transfer of this ORC system is studied and developed. The results show that with the increment of exhaust heat temperature, the mass flow rate of the working fluid, net power output and the system thermal efficiency will also increase. Consequently, total consumption of jet fuel could be significantly saved as well.

  16. Response of testosterone to prolonged aerobic exercise during different phases of the menstrual cycle.

    Science.gov (United States)

    O'Leary, C B; Lehman, C; Koltun, K; Smith-Ryan, A; Hackney, A C

    2013-09-01

    To examine the androgen response to exercise in women under conditions of high (H) and low (L) estrogen (E2) levels. Ten exercise trained eumenorrheic women (mean ± SD: 20.0 ± 2.2 years, 58.7 ± 8.3 kg, 22.3 ± 4.9 % body fat, VO2max = 50.7 ± 9.0 mL/kg/min) completed a 60 min treadmill run at ~70 % of VO2max during both the mid-follicular (L-E2, 69.7 ± 7.3 % VO2max) and mid-luteal (H-E2, 67.6 ± 7.9 % VO2max) phases of their menstrual cycle. Blood samples were taken pre-exercise (PRE), immediately post (POST), and 30 min into recovery (30R) from exercise and analyzed for total testosterone using ELISA assays. Results were analyzed using repeated measures ANOVA. Testosterone responses were (mean ± SD: L-E2, pre = 1.41 ± 0.21, post = 1.86 ± 0.21, 30R = 1.75 ± 0.32 nmol/L; H-E2, pre = 1.27 ± 0.23, post = 2.43 ± 0.56, 30R = 1.69 ± 0.34 nmol/L). Statistical analysis indicated no significant interaction existed between high and low estrogen conditions across the blood sampling times (p = 0.138). However, a main effect occurred for exercise (p 0.05). All testosterone hormonal concentrations immediately post-exercise greatly exceeded the level of hemoconcentration observed during the L-E2 and H-E2 exercise sessions. Prolonged aerobic exercise induces short-term elevations in testosterone in trained eumenorrheic women, which appears unrelated to estrogen levels and menstrual cycle phase. These increases may occur due to either increased androgen production and/or decreased degradation rates of the hormone, and are not solely the result of plasma fluid shifts from the exercise.

  17. Metabolic consequences of β-alanine supplementation during exhaustive supramaximal cycling and 4000-m time-trial performance.

    Science.gov (United States)

    Bellinger, Phillip M; Minahan, Clare L

    2016-08-01

    The present study investigated the effects of β-alanine supplementation on the resultant blood acidosis, lactate accumulation, and energy provision during supramaximal-intensity cycling, as well as the aerobic and anaerobic contribution to power output during a 4000-m cycling time trial (TT). Seventeen trained cyclists (maximal oxygen uptake = 4.47 ± 0.55 L·min(-1)) were administered 6.4 g of β-alanine (n = 9) or placebo (n = 8) daily for 4 weeks. Participants performed a supramaximal cycling test to exhaustion (equivalent to 120% maximal oxygen uptake) before (PreExh) and after (PostExh) the 4-week supplementation period, as well as an additional postsupplementation supramaximal cycling test identical in duration and power output to PreExh (PostMatch). Anaerobic capacity was quantified and blood pH, lactate, and bicarbonate concentrations were measured pre-, immediately post-, and 5 min postexercise. Subjects also performed a 4000-m cycling TT before and after supplementation while the aerobic and anaerobic contributions to power output were quantified. β-Alanine supplementation increased time to exhaustion (+12.8 ± 8.2 s; P = 0.041) and anaerobic capacity (+1.1 ± 0.7 kJ; P = 0.048) in PostExh compared with PreExh. Performance time in the 4000-m TT was reduced following β-alanine supplementation (-6.3 ± 4.6 s; P = 0.034) and the mean anaerobic power output was likely to be greater (+6.2 ± 4.5 W; P = 0.035). β-Alanine supplementation increased time to exhaustion concomitant with an augmented anaerobic capacity during supramaximal intensity cycling, which was also mirrored by a meaningful increase in the anaerobic contribution to power output during a 4000-m cycling TT, resulting in an enhanced overall performance.

  18. Working fluid selection for the Organic Rankine Cycle (ORC) exhaust heat recovery of an internal combustion engine power plant

    Science.gov (United States)

    Douvartzides, S.; Karmalis, I.

    2016-11-01

    Organic Rankine cycle technology is capable to efficiently convert low-grade heat into useful mechanical power. In the present investigation such a cycle is used for the recovery of heat from the exhaust gases of a four stroke V18 MAN 51/60DF internal combustion engine power plant operating with natural gas. Design is focused on the selection of the appropriate working fluid of the Rankine cycle in terms of thermodynamic, environmental and safety criteria. 37 candidate fluids have been considered and all Rankine cycles examined were subcritical. The thermodynamic analysis of all fluids has been comparatively undertaken and the effect of key operation conditions such as the evaporation pressure and the superheating temperature was taken into account. By appropriately selecting the working fluid and the Rankine cycle operation conditions the overall plant efficiency was improved by 5.52% and fuel consumption was reduced by 12.69%.

  19. The limits of the possible: models of power supply and demand in cycling.

    Science.gov (United States)

    Olds, T; Norton, K; Craig, N; Olive, S; Lowe, E

    1995-06-01

    This paper outlines a general strategy for mathematical modeling of cycling performance. This strategy involves formulating one expression describing the power available for external work from physiological sources. The variables used in this expression include maximal aerobic power (VO2max), fractional utilisation of VO2max, mechanical efficiency, maximal accumulated oxygen deficit, and the time constants relating to the expression of aerobic and anaerobic capacities. A second expression describing the power demand of cycling is then constructed. The variables used in this expression include the mass, projected frontal area and drag characteristics of the system, the coefficient of rolling resistance, environmental variables such as temperature, barometric pressure, relative humidity, wind speed and direction and the slope of the course. The two expressions are equated and solved using an iterative procedure. Two series of trials were used to assess the predictive accuracy of the model, one using track endurance performances and the other a 26 km road time-trial. The correlations between actual and predicted times have been excellent (0.92-0.95, p cycling performance. A range of options designed to improve cycling performance is described.

  20. Comparative evaluation of three alternative power cycles for waste heat recovery from the exhaust of adiabatic diesel engines

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, M.M.

    1985-07-01

    Three alternative power cycles were compared in application as an exhaust-gas heat-recovery system for use with advanced ''adiabatic'' diesel engines. The power cycle alternatives considered were steam Rankine, organic Rankine with RC-1 as the working fluid, and variations of an air Brayton cycle. The comparison was made in terms of fuel economy and economic payback potential for heavy-duty trucks operating in line-haul service. The results indicate that, in terms of engine rated specific fuel consumption, a diesel/alternative-power-cycle engine offers a significant improvement over the turbocompound diesel used as the baseline for comparison. The maximum improvement resulted from the use of a Rankine cycle heat-recovery system in series with turbocompounding. The air Brayton cycle alternatives studied, which included both simple-cycle and compression-intercooled configurations, were less effective and provided about half the fuel consumption improvement of the Rankine cycle alternatives under the same conditions. Capital and maintenance cost estimates were also developed for each of the heat-recovery power cycle systems. These costs were integrated with the fuel savings to identify the time required for net annual savings to pay back the initial capital investment. The sensitivity of capital payback time to arbitrary increases in fuel price, not accompanied by corresponding hardware cost inflation, was also examined. The results indicate that a fuel price increase is required for the alternative power cycles to pay back capital within an acceptable time period.

  1. Comparative evaluation of three alternative power cycles for waste heat recovery from the exhaust of adiabatic diesel engines

    Science.gov (United States)

    Bailey, M. M.

    1985-01-01

    Three alternative power cycles were compared in application as an exhaust-gas heat-recovery system for use with advanced adiabatic diesel engines. The power cycle alternatives considered were steam Rankine, organic Rankine with RC-1 as the working fluid, and variations of an air Brayton cycle. The comparison was made in terms of fuel economy and economic payback potential for heavy-duty trucks operating in line-haul service. The results indicate that, in terms of engine rated specific fuel consumption, a diesel/alternative-power-cycle engine offers a significant improvement over the turbocompound diesel used as the baseline for comparison. The maximum imporvement resulted from the use of a Rankine cycle heat-recovery system in series with turbocompounding. The air Brayton cycle alternatives studied, which included both simple-cycle and compression-intercooled configurations, were less effective and provided about half the fuel consumption improvement of the Rankine cycle alternatives under the same conditions. Capital and maintenance cost estimates were also developed for each of the heat-recovery power cycle systems. These costs were integrated with the fuel savings to identify the time required for net annual savings to pay back the initial capital investment. The sensitivity of capital payback time to arbitrary increases in fuel price, not accompanied by corresponding hardware cost inflation, was also examined. The results indicate that a fuel price increase is required for the alternative power cycles to pay back capital within an acceptable time period.

  2. Increases in glycogenin and glycogenin mRNA accompany glycogen resynthesis in human skeletal muscle

    DEFF Research Database (Denmark)

    Shearer, Jane; Wilson, Rhonda J.; Battram, Danielle S.

    2005-01-01

    Glycogenin is the self-glycosylating protein primer that initiates glycogen granule formation. To examine the role of this protein during glycogen resynthesis, eight male subjects exercised to exhaustion on a cycle ergometer at 75% VO2 max followed by five 30-s sprints at maximal capacity to furt...

  3. Seated versus standing cycling in competitive road cyclists: uphill climbing and maximal oxygen uptake.

    Science.gov (United States)

    Tanaka, H; Bassett, D R; Best, S K; Baker, K R

    1996-04-01

    Seven competitive road cyclists (M +/- SE = 23.7 +/- 1.5 yr, 70.5 +/- 1.7 kg) participated to determine the effects of cycling body position on physiological responses during uphill cycling and maximal oxygen uptake (VO2max). There was no significant difference in VO2max between seated and standing positions on a cycle ergometer (66.4 +/- 1.6 vs. 66.4 +/- 1.7 ml . kg-1 . min-1). When the subjects rode their own bicycle on a treadmill, oxygen uptake and heart rate were significantly (p < 0.05) higher during standing when subjects bicycled at 20.0 km . h-1 (4% grade), but no difference was observed when riding at 12.3 km . h-1 (10% grade). Leg RPE was significantly (p < 0.05) lower for standing position up a 10% grade. The results suggest that the standing position is less economical during moderate hill climbing, but during steep hill climbing, it results in a decreased sensation of effort in the legs.

  4. The application of soccer performance testing protocols to the non-elite player.

    Science.gov (United States)

    Siegler, J; Robergs, R; Weingart, H

    2006-03-01

    The application of performance testing for the evaluation of non-elite soccer players has received little attention. The purpose of this investigation was to use tests developed for elite soccer players to evaluate performance in non-elite soccer players and compare performance test results between elite (literature) and non-elite (data) players. Thirteen male soccer players volunteered to participate. The tests included a treadmill VO2max test, 20 m sprint, vertical jump (VJ), 30 s Wingate cycle ergometer test, the Loughborough Intermittent Shuttle Test (LIST), and 2 20-m multi-stage shuttle runs to exhaustion (fatigue test). Actual VO2max (absolute and relative) scores were correlated with the estimated VO2max scores (fatigue test), 20 m sprint, VJ, and 30 s Wingate using a Pearson's product-moment correlation. A paired t-test was conducted on the fatigue test trials. Non-significant relationships were observed between actual VO2max scores and estimated VO2max from the fatigue test (absolute and relative terms). Non-significant relationships were also observed between peak and average power output (Wingate), 20 m sprint, and VJ. Mean heart rates (HRs) throughout the LIST was 165+/-7 bpm, which represented 88% of HRmax. The results of this study demonstrate that to elicit physiological differences between elite and non-elite players, assessment must include both an aerobic and anaerobic component.

  5. High prevalence of false-positive plateau phenomena during VO2max testing in adolescents.

    Science.gov (United States)

    Beltrami, Fernando G; Wong, Del P; Noakes, Timothy D

    2014-09-01

    It is believed that a plateau in oxygen consumption (VO2) at the end of an incremental exercise test identifies the upper limits of cardiovascular capacity. We investigated how different criteria influence the frequency with which the "plateau phenomenon" is detected and the prevalence at which "false" plateau phenomena occurs during sub-maximal exercise. Cross-sectional. Six different criteria with 3 different sampling intervals each were used to identify the "plateau phenomenon" from a single data set comprising 63 incremental exercise tests along with secondary criteria based on target heart rate (HR) and respiratory exchange ratio (RER). A single criterion from the original 18 (HALF) was also used to detect the incidence of any plateau phenomena during each test. The plateau phenomenon was detected in 16-82% of the tests depending on the criteria used, mostly as a result of the different sampling intervals. HALF identified 103 "plateau phenomena" but 73 (70.9%) of these occurred during sub-maximal exercise and so were "false". "False" plateaus were verified by at least one secondary criterion in 27% of cases. Participants reached the HR and RER targets after 83.6 ± 11.7% and 81.9 ± 18.1% of total test duration, respectively. The wide range in the percentage of plateau phenomena detected by different criteria plus the high rate (71%) of "false" plateau during sub-maximal exercise could indicate that this phenomenon is a calculation artifact rather than an indicator of true physiological events. Secondary criteria can be reached early in exercise and often identify "false" plateau phenomena as "true". Copyright © 2013 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  6. Associations between VO2max and vitality in older workers: A cross-sectional study

    NARCIS (Netherlands)

    Strijk, J.E.; Proper, K.I.; Klaver, L.; Beek, A.J. van der; Mechelen, W. van

    2010-01-01

    Background. To prevent early exit from work, it is important to study which factors contribute to healthy ageing. One concept that is assumed to be closely related to, and therefore may influence healthy ageing, is vitality. Vitality consists of both a mental and a physical component, and is charact

  7. A Device and Methodology for Measuring Repetitive Lifting VO2max (Oxygen Consumption Rate)

    Science.gov (United States)

    1987-08-01

    and its estimate from skinfold thicknesses ; measurements on 481 men and women aged from 16 to 72 years. Br J Nutr 32:77-92. 3. Intaranont K, Ayoub MM...Justificaton --. By ......... AvaI~bty Co’der, L Ust Avdi iUl I r /1- Table of Contents Table of Contents iii List of Figures iv List of Tables v...during 28 repetitive lifting exercise iv List of Tables 1. Repetitive lifting device specifications 15 2. Subject sample descriptive data 24 3

  8. Performance analysis of exhaust heat recovery using organic Rankine cycle in a passenger car with a compression ignition engine

    Science.gov (United States)

    Ghilvacs, M.; Prisecaru, T.; Pop, H.; Apostol, V.; Prisecaru, M.; Pop, E.; Popescu, Gh; Ciobanu, C.; Mohanad, A.; Alexandru, A.

    2016-08-01

    Compression ignition engines transform approximately 40% of the fuel energy into power available at the crankshaft, while the rest part of the fuel energy is lost as coolant, exhaust gases and other waste heat. An organic Rankine cycle (ORC) can be used to recover this waste heat. In this paper, the characteristics of a system combining a compression ignition engine with an ORC which recover the waste heat from the exhaust gases are analyzed. The performance map of the diesel engine is measured on an engine test bench and the heat quantities wasted by the exhaust gases are calculated over the engine's entire operating region. Based on this data, the working parameters of ORC are defined, and the performance of a combined engine-ORC system is evaluated across this entire region. The results show that the net power of ORC is 6.304kW at rated power point and a maximum of 10% reduction in brake specific fuel consumption can be achieved.

  9. Physiological and biomechanical factors associated with elite endurance cycling performance.

    Science.gov (United States)

    Coyle, E F; Feltner, M E; Kautz, S A; Hamilton, M T; Montain, S J; Baylor, A M; Abraham, L D; Petrek, G W

    1991-01-01

    In this study we evaluated the physiological and biomechanical responses of "elite-national class" (i.e., group 1; N = 9) and "good-state class" (i.e., group 2; N = 6) cyclists while they simulated a 40 km time-trial in the laboratory by cycling on an ergometer for 1 h at their highest power output. Actual road racing 40 km time-trial performance was highly correlated with average absolute power during the 1 h laboratory performance test (r = -0.88; P less than 0.001). In turn, 1 h power output was related to each cyclists' VO2 at the blood lactate threshold (r = 0.93; P less than 0.001). Group 1 was not different from group 2 regarding VO2max (approximately 70 ml.kg-1.min-1 and 5.01 l.min-1) or lean body weight. However, group 1 bicycled 40 km on the road 10% faster than group 2 (P less than 0.05; 54 vs 60 min). Additionally, group 1 was able to generate 11% more power during the 1 h performance test than group 2 (P less than 0.05), and they averaged 90 +/- 1% VO2max compared with 86 +/- 2% VO2max in group 2 (P = 0.06). The higher performance power output of group 1 was produced primarily by generating higher peak torques about the center of the crank by applying larger vertical forces to the crank arm during the cycling downstroke. Compared with group 2, group 1 also produced higher peak torques and vertical forces during the downstroke even when cycling at the same absolute work rate as group 2. Factors possibly contributing to the ability of group 1 to produce higher "downstroke power" are a greater percentage of Type I muscle fibers (P less than 0.05) and a 23% greater (P less than 0.05) muscle capillary density compared with group 2. We have also observed a strong relationship between years of endurance training and percent Type I muscle fibers (r = 0.75; P less than 0.001). It appears that "elite-national class" cyclists have the ability to generate higher "downstroke power", possibly as a result of muscular adaptations stimulated by more years of endurance

  10. Carbohydrate mouth rinse enhances time to exhaustion during treadmill exercise.

    Science.gov (United States)

    Fraga, Cindy; Velasques, Bruna; Koch, Alexander J; Machado, Marco; Paulucio, Dailson; Ribeiro, Pedro; Pompeu, Fernando Augusto Monteiro Saboia

    2017-01-01

    Mouth rinsing with a CHO solution has been suggested to improve short (<1 h) endurance performance through central effect. We examined the effects of mouth rinsing with a CHO solution on running time to exhaustion on a treadmill. Six well-trained subjects ran to exhaustion at 85% VO2max , on three separate occasions. Subjects received either an 8% CHO solution or a placebo (PLA) every 15 min to mouth rinse (MR) or a 6% CHO solution to ingest (ING). Treatments were assigned in a randomized, counterbalanced fashion, with the mouth-rinsing treatments double-blinded. Blood samples were taken to assess glucose (Glu) and lactate (Lac), as well as the perceived exertion (RPE). Gas exchange and heart rate (HR) were collected during all trials. Subjects ran longer (P = 0·038) in both the MR (2583 ± 686 s) and ING (2625 ± 804 s) trials, compared to PLA (1935 ± 809 s), covering a greater distance (MR 9685 ± 3511·62 m; ING 9855 ± 4118·62; PLA 7295 ± 3727 m). RER was significantly higher in both ING and MR versus PLA. No difference among trials was observed for other metabolic or cardiovascular variables (VO2 , Lac, Glu, HR), nor for RPE. Endurance capacity, based on time to exhaustion on a treadmill, was improved when either mouth rinsing or ingesting a CHO solution, compared to PLA.

  11. Effects of 2-week intermittent training in hypobaric hypoxia on the aerobic energy metabolism and performance of cycling athletes with disabilities.

    Science.gov (United States)

    Kim, Sang-Hoon; An, Ho-Jung; Choi, Jung-Hyun; Kim, Yong-Youn

    2017-06-01

    [Purpose] The present study aimed at examining changes in aerobic energy metabolism and performance in cycling athletes after 2 weeks of intermittent training in a multistep hypobaric hypoxia environment. [Subjects and Methods] We also aimed at using the findings to propose an efficient training program in hypobaric hypoxia for endurance athletes with disabilities. The study participants were three cycling athletes with physical disabilities from the Korean national team (A, B, and C athletes). They underwent complex (repetition, interval, and continued) training with a roller-type cycle in a multistep hypobaric hypoxia environment (simulated altitude, 4,000 m above sea level). The training was conducted in twelve 60-min sessions for 2 weeks and it was based on the ventilatory threshold intensity, measured in an exercise stress test, conducted prior to training, at constant temperature (23 °C ± 2 °C) and humidity conditions (50% ± 5%). [Results] B and C athletes showed no noticeable changes in relative VO2max and HRmax values after training. A, B, and C athletes all showed increases in all-out time, 2'09″ (13.1%), 2'43″ (18.7%), and 1'22″ (7.4%), respectively after training. Although the relative VO2max and HRmax values were not improved, submaximal exercise performance ability was improved. [Conclusion] Therefore, 2 weeks of intermittent training in a hypobaric hypoxia environment positively affected aerobic energy metabolism and performance.

  12. 无训练年轻女性骑车与跑步的脂肪氧化动力学及最大脂肪氧化研究%Fat Oxidation Kinetics and Maximal Fat Oxidation of Untrained Young Women during Cycling and Running

    Institute of Scientific and Technical Information of China (English)

    张勇; 李之俊

    2013-01-01

    Objective The aim of the study is to compare the fat oxidation kinetics,exercise intensity eliciting maximal fat oxidation (Fatmax) and maximal fat oxidation rate (MFO) of untrained young women during cycling and running.Methods 12 healthy untrained young women performed two incremental exercise tests respectively on a cycle ergometer and a treadmill,and the gas metabolism data in the last 30 seconds of each load were measured to calculate fat oxidation rate,and then a 3rd polynomial fitting curve was used to determine fat oxidation kinetics curve,Fatmax and MFO.Results As exercise intensity increased,fat oxidation rate tended to increase first and then decrease.The higher levels of fat oxidation rate was seen in cycling at 50%-60% VO2max (4.48~4.68 mg/min/kg),and in running at 50%-65% VO2max(6.36~6.67 mg/min/kg).Fat oxidation rates were significantly higher during the running than the cycling at the same intensity,and Fatmax and MFO were significantly higher during running than cycling (56.51±2.50%VO2max vs 53.18±3.25%VO2max,P < 0.05;6.71±1.15 mg/min/kg vs 4.74±1.67 mg/min/kg,P < 0.001).The intensity,at which fat oxidation more than 95%MFO,were 44.86~60.60%VO2max for cycling and 48.21%~55.41%VO2max for running.Conclusion Fat oxidation rates,Fatmax and MFO were higher during running than cycling at the same intensity,suggesting that running could be better than cycling in the exercise intervention for obesity,diabetes and others associated with fat metabolism disorder.%目的:比较无训练年轻女性骑车与跑步的脂肪氧化动力学、最大脂肪氧化强度(Fatmax)和最大脂肪氧化率(MFO)的差异.方法:12名无训练年轻女性采用递增负荷模式分别完成自行车测试和跑台测试,测定每级负荷运动过程中机体的气体代谢指标,采用每级负荷后30秒气体代谢数据计算脂肪氧化率,通过3阶数多项式拟合曲线确定脂肪氧化动力曲线及Fatmax和MFO.结果:运动

  13. Ergogenic demands of a 24 hour cycling event.

    Science.gov (United States)

    White, J A; Ward, C; Nelson, H

    1984-09-01

    The maximal aerobic performance (VO2 max) and energy costs of cycling at various power outputs and equivalent road speeds of a highly trained endurance cyclist (age 23.4 yrs, height 1.95 m, weight 73.1 kg), were measured in the laboratory on an eddy-current cycle ergometer, and the physiological responses related to determinations made during a 24 h cycling time trial event, using continuous ECG recording from which estimates of ergogenic demands were obtained. The cyclist covered a distance of 694 km during the event at an average speed of 28.9 km.h-1 which corresponded to an equivalent oxygen cost of 38.5 ml.kg-1 min-1 and represented approximately 55% of his VO2 max. During the event, the cyclist expended an estimated 82,680 kJ of energy, of which approximately 44,278 kJ (54%) were supplied by repeated feedings of liquids, solids and semi-solids and some 38,402 kJ (46%) came from the stored energy reserves which resulted in a 1.19 kg loss of body weight during the event. The energy demands of the activity were more than three times greater than the highest recorded values of severe industrial work, and similar to the hourly rates of expenditure of shorter duration competitive events, but above the highest values reported over other extreme endurance events over the same period of time. The results thus represent near maximal levels of sustainable ergogenic effort by man over a complete 24 h cycle.

  14. Running kinematics and shock absorption do not change after brief exhaustive running.

    Science.gov (United States)

    Abt, John P; Sell, Timothy C; Chu, Yungchien; Lovalekar, Mita; Burdett, Ray G; Lephart, Scott M

    2011-06-01

    Because of the nature of running, the forces encountered require a proper coordination of joint action of the lower extremity to dissipate the ground reaction forces and accelerations through the kinetic chain. Running-related muscle fatigue may reduce the shock absorbing capacity of the lower extremity and alter running kinematics. The purpose of this study was to determine if a bout of exhaustive running at a physiologically determined high intensity, changes running kinematics, impact accelerations, and alters shock attenuating capabilities. It was hypothesized that as a result of fatigue induced by an exhaustive run, running kinematics, impact accelerations at the head and shank, acceleration reduction, and shock attenuation would change. A within-subject, repeated-measures design was used for this study. Twelve healthy, competitive male and female distance runners participated. Subjects performed 2 testing sessions consisting of a VO2max treadmill protocol to determine the heart rate at ventilatory threshold and a fatigue-inducing running bout at the identified ventilatory threshold heart rate. Kinematic data included knee flexion, pronation, time to maximum knee flexion, and time to maximum pronation. Acceleration data included shank acceleration, head acceleration, and shock attenuation. No significant differences resulted for the kinematic or acceleration variables. Although the results of this study do not support the original hypotheses, the influence of running fatigue on kinematics and accelerations remains inconclusive. Future research is necessary to examine fatigue-induced changes in running kinematics and accelerations and to determine the threshold at which point the changes may occur.

  15. Three Consecutive Days of Interval Runs to Exhaustion Affects Lymphocyte Subset Apoptosis and Migration

    Directory of Open Access Journals (Sweden)

    James W. Navalta

    2014-01-01

    Full Text Available This investigation assessed the lymphocyte subset response to three days of intermittent run exercise to exhaustion. Twelve healthy college-aged males (n=8 and females (n=4 (age = 26 ± 4 years; height = 170.2 ± 10 cm; body mass = 75 ± 18 kg completed an exertion test (maximal running speed and VO2max and later performed three consecutive days of an intermittent run protocol to exhaustion (30 sec at maximal running speed and 30 sec at half of the maximal running speed. Blood was collected before exercise (PRE and immediately following the treadmill bout (POST each day. When the absolute change from baseline was evaluated (i. e., Δ baseline, a significant change in CD4+ and CD8+ for CX3CR1 cells was observed by completion of the third day. Significant changes in both apoptosis and migration were observed following two consecutive days in CD19+ lymphocytes, and the influence of apoptosis persisted following the third day. Given these lymphocyte responses, it is recommended that a rest day be incorporated following two consecutive days of a high-intensity intermittent run program to minimize immune cell modulations and reduce potential susceptibility.

  16. Acute effects of a thermogenic nutritional supplement on cycling time to exhaustion and muscular strength in college-aged men

    Directory of Open Access Journals (Sweden)

    Beck Travis W

    2009-07-01

    Full Text Available Abstract Background The purpose of the present study was to examine the acute effects of a thermogenic nutritional supplement containing caffeine, capsaicin, bioperine, and niacin on muscular strength and endurance performance. Methods Twenty recreationally-active men (mean ± SD age = 21.5 ± 1.4 years; stature = 178.2 ± 6.3 cm; mass = 76.5 ± 9.9 kg; VO2 PEAK = 3.05 ± 0.59 L/min-1 volunteered to participate in this randomized, double-blinded, placebo-controlled, cross-over study. All testing took place over a three-week period, with each of the 3 laboratory visits separated by 7 days (± 2 hours. During the initial visit, a graded exercise test was performed on a Lode Corival cycle ergometer (Lode, Groningen, Netherlands until exhaustion (increase of 25 W every 2 min to determine the maximum power output (W at the VO2 PEAK (Parvo Medics TrueOne® 2400 Metabolic Measurement System, Sandy, Utah. In addition, one-repetition maximum (1-RM strength was assessed using the bench press (BP and leg press (LP exercises. During visits 2 and 3, the subjects were asked to consume a capsule containing either the active supplement (200 mg caffeine, 33.34 mg capsaicin, 5 mg bioperine, and 20 mg niacin or the placebo (175 mg of calcium carbonate, 160 mg of microcrystalline cellulose, 5 mg of stearic acid, and 5 mg of magnesium stearate in an identical capsule 30 min prior to the testing. Testing included a time-to-exhaustion (TTE ride on a cycle ergometer at 80% of the previously-determined power output at VO2 PEAK followed by 1-RM LP and BP tests. Results There were no differences (p > 0.05 between the active and placebo trials for BP, LP, or TTE. However, for the BP and LP scores, the baseline values (visit 1 were less than the values recorded during visits 2 and 3 (p ≤ 0.05. Conclusion Our findings indicated that the active supplement containing caffeine, capsaicin, bioperine, and niacin did not alter muscular strength or cycling endurance when compared

  17. Secondary organic aerosol production from diesel vehicle exhaust: impact of aftertreatment, fuel chemistry and driving cycle

    Science.gov (United States)

    Gordon, T. D.; Presto, A. A.; Nguyen, N. T.; Robertson, W. H.; Na, K.; Sahay, K. N.; Zhang, M.; Maddox, C.; Rieger, P.; Chattopadhyay, S.; Maldonado, H.; Maricq, M. M.; Robinson, A. L.

    2014-05-01

    Environmental chamber ("smog chamber") experiments were conducted to investigate secondary organic aerosol (SOA) production from dilute emissions from two medium-duty diesel vehicles (MDDVs) and three heavy-duty diesel vehicles (HDDVs) under urban-like conditions. Some of the vehicles were equipped with emission control aftertreatment devices, including diesel particulate filters (DPFs), selective catalytic reduction (SCR) and diesel oxidation catalysts (DOCs). Experiments were also performed with different fuels (100% biodiesel and low-, medium- or high-aromatic ultralow sulfur diesel) and driving cycles (Unified Cycle,~Urban Dynamometer Driving Schedule, and creep + idle). During normal operation, vehicles with a catalyzed DPF emitted very little primary particulate matter (PM). Furthermore, photooxidation of dilute emissions from these vehicles produced essentially no SOA (below detection limit). However, significant primary PM emissions and SOA production were measured during active DPF regeneration experiments. Nevertheless, under reasonable assumptions about DPF regeneration frequency, the contribution of regeneration emissions to the total vehicle emissions is negligible, reducing PM trapping efficiency by less than 2%. Therefore, catalyzed DPFs appear to be very effective in reducing both primary PM emissions and SOA production from diesel vehicles. For both MDDVs and HDDVs without aftertreatment substantial SOA formed in the smog chamber - with the emissions from some vehicles generating twice as much SOA as primary organic aerosol after 3 h of oxidation at typical urban VOC / NOx ratios (3 : 1). Comprehensive organic gas speciation was performed on these emissions, but less than half of the measured SOA could be explained by traditional (speciated) SOA precursors. The remainder presumably originates from the large fraction (~30%) of the nonmethane organic gas emissions that could not be speciated using traditional one-dimensional gas chromatography. The

  18. Sustained PU.1 levels balance cell-cycle regulators to prevent exhaustion of adult hematopoietic stem cells.

    Science.gov (United States)

    Staber, Philipp B; Zhang, Pu; Ye, Min; Welner, Robert S; Nombela-Arrieta, César; Bach, Christian; Kerenyi, Marc; Bartholdy, Boris A; Zhang, Hong; Alberich-Jordà, Meritxell; Lee, Sanghoon; Yang, Henry; Ng, Felicia; Zhang, Junyan; Leddin, Mathias; Silberstein, Leslie E; Hoefler, Gerald; Orkin, Stuart H; Göttgens, Berthold; Rosenbauer, Frank; Huang, Gang; Tenen, Daniel G

    2013-03-07

    To provide a lifelong supply of blood cells, hematopoietic stem cells (HSCs) need to carefully balance both self-renewing cell divisions and quiescence. Although several regulators that control this mechanism have been identified, we demonstrate that the transcription factor PU.1 acts upstream of these regulators. So far, attempts to uncover PU.1's role in HSC biology have failed because of the technical limitations of complete loss-of-function models. With the use of hypomorphic mice with decreased PU.1 levels specifically in phenotypic HSCs, we found reduced HSC long-term repopulation potential that could be rescued completely by restoring PU.1 levels. PU.1 prevented excessive HSC division and exhaustion by controlling the transcription of multiple cell-cycle regulators. Levels of PU.1 were sustained through autoregulatory PU.1 binding to an upstream enhancer that formed an active looped chromosome architecture in HSCs. These results establish that PU.1 mediates chromosome looping and functions as a master regulator of HSC proliferation.

  19. Time to exhaustion at continuous and intermittent maximal lactate steady state during running exercise.

    Science.gov (United States)

    Dittrich, Naiandra; de Lucas, Ricardo Dantas; Beneke, Ralph; Guglielmo, Luiz Guilherme

    2014-09-01

    The purpose of this study was to determine and compare the time to exhaustion (TE) and the physiological responses at continuous and intermittent (ratio 5:1) maximal lactate steady state (MLSS) in well-trained runners. Ten athletes (32.7 ± 6.9 y, VO2max 61.7 ± 3.9 mL · kg-1 · min-1) performed an incremental treadmill test, three to five 30-min constant-speed tests to determine the MLSS continuous and intermittent (5 min of running, interspaced by 1 min of passive rest), and 2 randomized TE tests at such intensities. Two-way ANOVA with repeated measures was used to compare the changes in physiological variables during the TE tests and between continuous and intermittent exercise. The intermittent MLSS velocity (MLSSint = 15.26 ± 0.97 km/h) was higher than in the continuous model (MLSScon = 14.53 ± 0.93 km/h), while the TE at MLSScon was longer than MLSSint (68 ± 11 min and 58 ± 15 min, P heart rate, ventilation, and rating of perceived exertion presented a significant increase in the last portion of the tests. The results showed a higher tolerance to exercising during MLSScon than during MLSSint in trained runners. Thus, the training volume of an extensive interval session (ratio 5:1) designed at MLSS intensity should take into consideration this higher speed at MLSS and also the lower TE than with continuous exercise.

  20. Improved time to exhaustion following ingestion of the energy drink Amino Impact™

    Directory of Open Access Journals (Sweden)

    Ratamess Nicholas A

    2010-04-01

    Full Text Available Abstract Background The purpose of this study was to examine the effect of a commercially available energy drink on time to exhaustion during treadmill exercise. In addition, subjective measures of energy, focus, and fatigue were examined Methods Fifteen subjects (9 men and 6 women; 20.9 ± 1.0 y; 172.1 ± 9.1 cm; 71.0 ± 9.4 kg; 16.9 ± 9.7% body fat underwent two testing sessions administered in a randomized, double-blind fashion. Subjects reported to the laboratory in a 3-hr post-absorptive state and were provided either the supplement (SUP; commercially marketed as Amino Impact™ or placebo (P. During each laboratory visit subjects performed a treadmill run (70% VO2 max to exhaustion. Mean VO2 was measured during each endurance exercise protocol. Subjects were required to complete visual analog scales for subjective measures of energy, focus and fatigue at the onset of exercise (PRE, 10-mins into their run (EX10 and immediately post-exercise (IP. Results Time to exhaustion was significantly greater (p = 0.012 during SUP than P. Subjects consuming the supplement were able to run 12.5% longer than during the placebo treatment. Subjects consuming SUP reported significantly greater focus (p = 0.031, energy (p = 0.016, and less fatigue (p = 0.005 at PRE. Significant differences between groups were seen at EX10 for focus (p = 0.026 and energy (p = 0.004, but not fatigue (p = 0.123. No differences were seen at IP for either focus (p = 0.215, energy (p = 0.717 or fatigue (p = 0.430. Conclusions Results of this study indicate that the supplement Amino Impact™ can significantly increase time to exhaustion during a moderate intensity endurance run and improve subjective feelings of focus, energy and fatigue.

  1. Effect of Exercise Intensity on Differentiated and Undifferentiated Ratings of Perceived Exertion During Cycle and Treadmill Exercise in Recreationally Active and Trained Women

    Science.gov (United States)

    Bolgar, Melinda R.; Baker, Carol E.; Goss, Fredric. L.; Nagle, Elizabeth; Robertson, Robert J.

    2010-01-01

    The purpose of the study is to examine the effect of aerobic exercise intensity on components of the differentiated perceived exertion model in young women performing weight bearing and non-weight bearing aerobic exercise. Subjects were 18-25 yr old women who were recreationally active (n = 19; VO2max = 33.40 ml·kg-1·min-1) and trained (N = 22; VO2max = 43.3 ml·kg-1·min-1). Subjects underwent two graded exercise tests (GXT) on a treadmill and bike which were separated by 48 hours. RPE-Overall, -Legs, and -Chest, as well as oxygen uptake (VO2) and heart rate were recorded each minute. Individual regression analyses were used to identify RPE-Overall,-Legs, and -Chest at 40, 60, 80% VO2max/peak. Separate two factor (site (3) x intensity (3)) ANOVAs with repeated measures on site and intensity were computed for each training status. Furthermore, RPE responses were also examined with a one factor (site (3)) within subject ANOVA with repeated measure on site at the ventilatory breakpoint. For both the recreationally active and trained groups no significant differences were observed for RPE-Overall, -Legs, and -Chest during treadmill exercise. However, for cycling exercise results indicated that RPE-Legs was significantly greater at all exercise intensities than RPE-Overall and RPE-Chest for trained subjects while for recreationally active subjects RPE-Legs was only significantly higher at the highest exercise intensity. Responses at the ventilatory breakpoint during cycle exercise indicated that RPE-Legs was significantly greater than RPE-Chest and RPE-Overall for trained subjects but not for recreationally active subjects. Signal dominance was not observed at an intensity equivalent to the ventilatory breakpoint during treadmill exercise in either of the groups. In recreationally active and trained females signal dominance was demonstrated only during cycling exercise, but not during treadmill exercise. Signal integration could not be demonstrated during cycling and

  2. Improved cycling performance with ingestion of hydrolyzed marine protein depends on performance level

    Directory of Open Access Journals (Sweden)

    Vegge Geir

    2012-04-01

    Full Text Available Abstract Background The effect on performance of protein ingestion during or after exercise is not clear. This has largely been attributed to the utilization of different scientific protocols and the neglection of accounting for factors such as differences in physical and chemical properties of protein supplements and differences in athletic performance level. Methods We hypothesized that ingestion of unprocessed whey protein (15.3 g·h-1 together with carbohydrate (60 g·h-1, would provide no ergogenic effect on 5-min mean-power performance following 120 min cycling at 50% of maximal aerobic power (2.8 ± 0.2 W·kg-1, corresponding to 60 ± 4% of VO2max, compared to CHO alone (60 g·h-1. Conversely, we hypothesized that ingestion of the hydrolyzed marine protein supplement NutriPeptin™ (Np, 2.7 g·h-1, a processed protein supplement with potentially beneficial amino acid composition, together with a PROCHO beverage (12.4 g·h-1 and 60 g·h-1, respectively would provide an ergogenic effect on mean-power performance. We also hypothesized that the magnitude of the ergogenic effect of NpPROCHO would be dependent on athletic performance. As for the latter analysis, performance level was defined according to a performance factor, calculated from individual pre values of Wmax, VO2max and 5-min mean-power performance, wherein the performance of each subject was ranked relative to the superior cyclist whos performance was set to one. Twelve trained male cyclists (VO2max = 65 ± 4 ml·kg-1·min-1 participated in a randomized double-blinded cross-over study. Results and conclusions Overall, no differences were found in 5-min mean-power performance between either of the beverages (CHO 5.4 ± 0.5 W·kg-1; PROCHO 5.3 ± 0.5 W·kg-1; NpPROCHO 5.4 ± 0.3 W·kg-1 (P = 0.29. A negative correlation was found between NpPROCHO mean-power performance and athletic performance level (using CHO-performance as reference; Pearson R = -0.74, P = 0.006. Moreover

  3. Acute and 2 days delayed effects of exhaustive stretch-shortening cycle exercise on barefoot walking and running patterns.

    Science.gov (United States)

    Morio, Cédric; Nicol, Caroline; Barla, Charlie; Barthèlemy, Joëlle; Berton, Eric

    2012-08-01

    This study investigated the acute and 2 days delayed influences of exhaustive stretch-shortening cycle exercise (SSC) on barefoot walking and running gait patterns. The SSC exercise was performed on a sledge apparatus, on which the subjects (N = 10) repeated until exhaustion intermittent series of 25 bilateral submaximal rebounds. Maximal drop-jumps and submaximal barefoot treadmill walking and running were performed before (PRE) and after (POST) the exhaustive exercise and repeated 48 h (D2) later. Electromyographic activity and 3D kinematics of the right lower limb and foot were recorded for 15 s at gait initiation (BEG) and at the end (END: at 3 min of walk and 5 min of run). The exhaustive SSC exercise resulted in 6% reductions in maximal drop jump performance at POST and D2, and affected mostly both gait patterns at D2. The walking pattern presented compensatory neural adjustments within the triceps surae muscle group. This expected pain-induced protective strategy of the soleus muscle was sufficient to preserve the kinematics pattern. The running condition revealed a major knee strategy, which might support the concept of pain protective strategy of knee extensor muscles at the expense of impact cushioning. Regardless the testing session, most parameters showed fatigue-induced changes at gait initiation (BEG), which were opposite to subsequent BEG to END adjustments. This is likely to support anticipatory strategies rather than progressive adjustments during the exercise.

  4. EFFECT OF EXERCISE INTENSITY ON DIFFERENTIATED AND UNDIFFERENTIATED RATINGS OF PERCEIVED EXERTION DURING CYCLE AND TREADMILL EXERCISE IN RECREATIONALLY ACTIVE AND TRAINED WOMEN

    Directory of Open Access Journals (Sweden)

    Melinda R. Bolgar

    2010-12-01

    Full Text Available The purpose of the study is to examine the effect of aerobic exercise intensity on components of the differentiated perceived exertion model in young women performing weight bearing and non-weight bearing aerobic exercise. Subjects were 18-25 yr old women who were recreationally active (n = 19; VO2max = 33.40 ml·kg-1·min-1 and trained (N = 22; VO2max = 43.3 ml·kg-1·min-1. Subjects underwent two graded exercise tests (GXT on a treadmill and bike which were separated by 48 hours. RPE-Overall, -Legs, and -Chest, as well as oxygen uptake (VO2 and heart rate were recorded each minute. Individual regression analyses were used to identify RPE-Overall,-Legs, and -Chest at 40, 60, 80% VO2max/peak. Separate two factor (site (3 x intensity (3 ANOVAs with repeated measures on site and intensity were computed for each training status. Furthermore, RPE responses were also examined with a one factor (site (3 within subject ANOVA with repeated measure on site at the ventilatory breakpoint. For both the recreationally active and trained groups no significant differences were observed for RPE-Overall, -Legs, and -Chest during treadmill exercise. However, for cycling exercise results indicated that RPE-Legs was significantly greater at all exercise intensities than RPE-Overall and RPE-Chest for trained subjects while for recreationally active subjects RPE-Legs was only significantly higher at the highest exercise intensity. Responses at the ventilatory breakpoint during cycle exercise indicated that RPE-Legs was significantly greater than RPE-Chest and RPE-Overall for trained subjects but not for recreationally active subjects. Signal dominance was not observed at an intensity equivalent to the ventilatory breakpoint during treadmill exercise in either of the groups. In recreationally active and trained females signal dominance was demonstrated only during cycling exercise, but not during treadmill exercise. Signal integration could not be demonstrated during

  5. Carbohydrate Mouth Rinse Maintains Muscle Electromyographic Activity and Increases Time to Exhaustion during Moderate but not High-Intensity Cycling Exercise

    Directory of Open Access Journals (Sweden)

    Victor José Bastos-Silva

    2016-03-01

    Full Text Available The aim was to investigate the influence of a carbohydrate (CHO mouth rinse on the vastus lateralis (VL and rectus femoris (RF electromyographic activity (EMG and time to exhaustion (TE during moderate (MIE and high-intensity cycling exercise (HIE. Thirteen participants cycled at 80% of their respiratory compensation point and at 110% of their peak power output to the point of exhaustion. Before the trials and every 15 min during MIE, participants rinsed with the CHO or Placebo (PLA solutions. The root mean square was calculated. CHO had no effect on the TE during HIE (CHO: 177.3 ± 42.2 s; PLA: 163.0 ± 26.7 s, p = 0.10, but the TE was increased during MIE (CHO: 76.6 ± 19.7 min; PLA: 65.4 ± 15.2 min; p = 0.01. The EMG activity in the VL was higher than PLA at 30 min (CHO: 10.5% ± 2.6%; PLA: 7.7% ± 3.3%; p = 0.01 and before exhaustion (CHO: 10.3% ± 2.5%; PLA: 8.0% ± 2.9%; p = 0.01 with CHO rinsing. There was no CHO effect on the EMG activity of RF during MIE or for VL and RF during HIE. CHO mouth rinse maintains EMG activity and enhances performance for MIE but not for HIE.

  6. Oxygen cost of internal work during cycling.

    Science.gov (United States)

    Francescato, M P; Girardis, M; di Prampero, P E

    1995-01-01

    The energy cost of internal work and its relationships with lower limb mass and pedalling frequency were studied in four male subjects [age 22.2 (SD 1.5) years, body mass 81.0 (SD 5.1) kg, maximal O2 uptake (VO2max) above resting 3.06 (SD 0.4) l.min-1]. The subjects cycled at 40, 60, 80 and 100 rpm and at five different exercise intensities for every pedalling frequency (unloaded condition, UL); the same exercises were repeated after having increased the lower limbs' masses by 40% (loaded condition, L). The exercise intensities were chosen so that the oxygen consumption (VO2) did not exceed 75% of VO2max. For all the subjects and all the conditions, the rate of VO2 above resting increased linearly with the mechanical power (W). The y-intercepts of the linear regressions of VO2 on W, normalised per kilogram of overall lower limbs mass were the same in both UL and L and increased with the 4.165 power of pedalling frequency (fp). These intercepts were taken to represent the metabolic counterpart of the internal power dissipation in cycling; they amounted to 0.78, 0.34, 3.29 and 10.30 W.kg-1 for pedalling frequencies of 40, 60, 80 and 100 rpm respectively. The slope of the regression lines (delta W/delta VO2) represents the delta efficiency of cycle ergometer exercise; this was also affected by fp, ranging, on average, from 22.9% to 32.0%. These data allowed us to obtain a comprehensive description of the effects of fp (per minute), exercise intensity (W, watts) and lower limbs' mass with or without added loads (mL, kg), on VO2 (ml.min-1) during cycling: VO2 = [mL.(4.3.10(-8).fp4.165/0.35)] + (1/[(3.594.10(-5).fp2 - 0.003.fp + 0.326).0.35]).W. The mean percentage error between the VO2 predicted from this equation and the actual value was 12.6%. This equation showed that the fraction of the overall VO2 due to internal work, for a normal 70-kg subject pedalling at 60 rpm and 100 W was of the order of 0.2.

  7. Effects of Vitamin-E Supplementation on Cardiorespiratory Responses in Female Athletes during Endurance Exercise in Different Phases of Menstrual Cycle

    Directory of Open Access Journals (Sweden)

    Pratima Chatterjee

    2011-10-01

    Full Text Available Background: Ability to perform strenuous physical work is largely dependent on the efficiency of cardiorespiratory system to take up, transport and give off oxygen for its utilization by the working muscles. Cardiorepsiratory responses to exercise and alteration in physical work capacity of females during different phases of menstrual cycle have been reported. It is well established that Vitamin E (Vit-E supplementation improves aerobic performance due to its antioxidant nature. Objectives: The present study was aimed to determine the effects of Vit-E supplementation on cardiorespiratory responses during endurance exercise in different phases of menstrual cycle in female athletes. Methods: Twenty five unmarried adult female athletes (21–25 years were recruited in this placebo-control double-blind randomized experimental trial. Their average duration of menstrual cycle was 28–32 days. Vit-E was supplemented at a dose of 400mg.day-1 for 7 days. Results: The pre-exercise heart rate and peak heart rate were significantly higher in the flow phase than the follicular and luteal phases during pre and post-supplemental trials. The post-supplementation values of maximum oxygen uptake (VO2max, O2 pulse, maximum pulmonary ventilation and endurance capacity were significantly (P<0.001 higher than the pre-supplementation values in all the phases of menstrual cycle. As far as the comparison of these parameters between the different phases of menstrual cycle is concerned, all these parameters were significantly different in the flow phase than their corresponding values in the follicular and luteal phases. From the present investigation it is concluded that Vit-E supplementation at a dose of 400 mg.day-1 for 7 days significantly improved the VO2max, maximum voluntary ventilation, O2 pulse and endurance capacity in female athletes during different phases of menstrual cycle. Conclusion: Therefore, such supplementation may be recommended to improve the

  8. A COMPARISON OF THE EFFECTS OF FATIGUE ON SUBJECTIVE AND OBJECTIVE ASSESSMENT OF SITUATION AWARENESS IN CYCLING

    Directory of Open Access Journals (Sweden)

    Wade L. Knez

    2006-03-01

    Full Text Available Maximal effort on a 30 km Time Trial (TT30 was examined to assess whether it would elicit changes in objective and subjective tests of the participants' perception of the environment and their ability to anticipate future occurrences (situation awareness; SA and to determine the effect of post-exercise recovery on SA. Nine experienced (5.22 ± 2.77 years road cyclists had their objective and subjective levels of SA assessed prior to and at the completion of two TT30. The participants' results were compared to measurements of maximal oxygen uptake (VO2max, peak power output (PPO, age and years of competitive cycle racing experience. Fatigue resulting from maximal effort on a TT30 produced significant changes in both the objective and subjective test of SA. Effect sizes of 0.93 and 0.99 indicated that the first and second TT30 were likely or almost certain to have a beneficial effect on the objective assessment of SA. However, the effect sizes of 0.97 and 0.95 relating to the subjective assessment of cognitive performance on the first and second TT30 showed that it was very likely the participants' had an increased difficulty in maintaining SA. A recovery period of up to three minutes post TT30 had no effect on SA. Changes in SA had no relationship with measurements of VO2max, peak power output (PPO, age and years of competitive cycle racing experience. The findings suggest that within a laboratory environment, participants consistently underestimate their ability to make accurate assessments of their cycling environment compared to objective measures of their SA

  9. 高镍铸铁排气歧管低周热疲劳研究%Low Cycle Thermal Fatigue of High Nickel Cast Iron Exhaust Manifold

    Institute of Scientific and Technical Information of China (English)

    袁守利; 王超; 刘志恩; 李雪妮

    2014-01-01

    针对某新开发的车用高镍铸铁排气歧管进行了低周热疲劳寿命预测研究,为获取准确的热边界条件,采用STAR-CCM+与有限元软件进行基于疲劳寿命试验条件的非稳态耦合传热分析,得到了排气歧管的对流换热系数和温度场,建立了具有真实装配关系并施加螺栓预紧力的排气歧管有限元模型,在对等效塑性应变分析的基础上,结合Coffin-Manson公式进行寿命预测。结果表明,在排气歧管开发过程中,采用该方法可以快速对其热疲劳寿命进行评估。%The low cycle thermal fatigue life of a newly developed high nickel cast iron exhaust manifold for vehicle was pre -dicted.In order to obtain a more accurate thermal boundary condition , STAR-CCM+and FE software were applied to analyze non-steady coupled heat transfer based on fatigue life experiment .The convective heat transfer coefficient and temperature field of exhaust manifold were then obtained .The FE model of the exhaust manifold was established with accurate assembly relation a-mong different components and bolt pre -tightening loads .At last, using Coffin-Manson equation , life prediction was completed based on analysis of equivalent plastic strain .The result indicates that the analysis method could speed up thermal fatigue life prediction of an exhaust manifold during developing process .

  10. Effect of blood haemoglobin concentration on V(O2,max) and cardiovascular function in lowlanders acclimatised to 5260 m

    DEFF Research Database (Denmark)

    Calbet, J A L; Rådegran, G; Boushel, Robert Christopher

    2002-01-01

    +/- 5 to 185 +/- 5 g l(-1) (P delivery was reduced...... and maximal V(O(2)) was thus maintained by higher O(2) extraction. While CO increased linearly with work rate irrespective of [Hb] or inspired oxygen fraction (F(I,O(2))), both LBF and leg vascular conductance were systematically higher when [Hb] was low. Close and significant relationships were seen between...

  11. Effects of exercise and group counselling on body composition and VO(2max) in overweight women with polycystic ovary syndrome

    DEFF Research Database (Denmark)

    Roessler, Kirsten Kaya; Birkebaek, Camilla; Ravn, Pernille

    2013-01-01

    BACKGROUND: Polycystic ovary syndrome (PCOS) is often associated with an increased waist circumference and with lower cardio-respiratory fitness as a consequence of obesity, which may be improved by physical activity. OBJECTIVE: To investigate the effect of high-intensity aerobic training combined...... with group counselling sessions on anthropometry and cardio-respiratory fitness in women with PCOS. DESIGN: Seventeen sedentary, overweight women with PCOS were randomized in a cross-over design to 16 weeks of intervention: Eight weeks high intensity aerobic exercise was followed by eight weeks group...

  12. Changes in VO2 Max. Resulting from Bicycle Training at Different Intensities Holding Total Mechanical Work Constant.

    Science.gov (United States)

    Burke, Edmund A., Jr.; Franks, B. Don

    Effects of different training intensities on oxygen intake were determined in this study. Sixteen male subjects aged 16-18 were randomly assigned to one of three training groups or a control group. The training groups trained 3 days per week on bicycle ergometers at different intensities (85 percent, 75 percent, or 65 percent of heart rate…

  13. Maximal heart rate does not limit cardiovascular capacity in healthy humans: insight from right atrial pacing during maximal exercise.

    Science.gov (United States)

    Munch, G D W; Svendsen, J H; Damsgaard, R; Secher, N H; González-Alonso, J; Mortensen, S P

    2014-01-15

    In humans, maximal aerobic power (VO2 max ) is associated with a plateau in cardiac output (Q), but the mechanisms regulating the interplay between maximal heart rate (HRmax) and stroke volume (SV) are unclear. To evaluate the effect of tachycardia and elevations in HRmax on cardiovascular function and capacity during maximal exercise in healthy humans, 12 young male cyclists performed incremental cycling and one-legged knee-extensor exercise (KEE) to exhaustion with and without right atrial pacing to increase HR. During control cycling, Q and leg blood flow increased up to 85% of maximal workload (WLmax) and remained unchanged until exhaustion. SV initially increased, plateaued and then decreased before exhaustion (P rate pressure product and RAP (P heart can be paced to a higher HR than observed during maximal exercise, suggesting that HRmax and myocardial work capacity do not limit VO2 max in healthy individuals. A limited left ventricular filling and possibly altered contractility reduce SV during atrial pacing, whereas a plateau in LVFP appears to restrict Q close to VO2 max .

  14. Measuring submaximal performance parameters to monitor fatigue and predict cycling performance: a case study of a world-class cyclo-cross cyclist.

    Science.gov (United States)

    Lamberts, Robert P; Rietjens, Gerard J; Tijdink, Hendrik H; Noakes, Timothy D; Lambert, Michael I

    2010-01-01

    Recently a novel submaximal test, known as the Lamberts and Lambert submaximal cycle test (LSCT), has been developed with the purpose of monitoring and predicting changes in cycling performance. Although this test has been shown to be reliable and able to predict cycling performance, it is not known whether it can measure changes in training status. Therefore, the aim of this study was to determine whether the LSCT is able to track changes in performance parameters, and objective and subjective markers of well-being. A world class cyclo-cross athlete (31 years) volunteered to participate in a 10-week observational study. Before and after the study, a peak power output (PPO) test with respiratory gas analysis (VO(2max)) and a 40-km time trial (40-km TT) test were performed. Training data were recorded in a training logbook with a daily assessment of well-being, while a weekly LSCT was performed. After the training period all performance parameters had improved by a meaningful amount (PPO +5.2%; 40-km TT time -2.5%; VO(2max) +1.4%). Increased training loads during weeks 2 and 6 and the subsequent training-induced fatigue was reflected in the increased well-being scores. Changes during the LSCT were most clearly notable in (1) increased power during the first minute of third stage, (2) increased rating of perceived exertion during second and third stages, and (3) a faster heart rate recovery after the third stage. In conclusion, these data suggest that the LSCT is able to track changes in training status and detect the consequences of sharp increases in training loads which seem to be associated with accumulating fatigue.

  15. Leading a Culture of Fitness

    Science.gov (United States)

    2011-03-24

    Program. As shown earlier, VO2max is a good indicator of cardio respiratory fitness. A maximum effort test on a treadmill is one of the most...accepted and accurate methods to determine VO2max , but the test is lengthy, complicated, and comes with risks. To avoid these drawbacks, the Air Force 9...adopted a sub-maximal cycle ergometry test (SCET) designed to estimate VO2max . These tests were accurate within the range of ten to twenty percent

  16. Documentation for the USAF School of Aerospace Medicine Altitude Decompression Sickness Research Database

    Science.gov (United States)

    2010-05-01

    with a SensorMedics 2900Z Metabolic Measurement Cart (Wiegman et al., 1993; Pilmanis et al., 1999). From the VO2max obtained during the Bruce test ...of the oxygen consumption was accomplished with a SensorMedics 2900Z Metabolic Measurement Cart. From the VO2max obtained during the Bruce test ...derived from the: US Air Force cycle ergometry fitness test estimate of VO2max ; a Bruce Protocol Treadmill test ; or a VO2peak determined with a dual

  17. Maximal heart rate does not limit cardiovascular capacity in healthy humans

    DEFF Research Database (Denmark)

    Munch, G D W; Svendsen, J H; Damsgaard, R

    2014-01-01

    In humans, maximal aerobic power (VO2 max ) is associated with a plateau in cardiac output (Q), but the mechanisms regulating the interplay between maximal heart rate (HRmax) and stroke volume (SV) are unclear. To evaluate the effect of tachycardia and elevations in HRmax on cardiovascular function...... and capacity during maximal exercise in healthy humans, 12 young male cyclists performed incremental cycling and one-legged knee-extensor exercise (KEE) to exhaustion with and without right atrial pacing to increase HR. During control cycling, Q and leg blood flow increased up to 85% of maximal workload (WLmax...... and RAP (P exercise, suggesting that HRmax and myocardial work capacity do not limit VO2 max in healthy...

  18. A comparison of rectal, oesophageal and gastro-intestinal tract temperatures during moderate-intensity cycling in temperate and hot conditions.

    Science.gov (United States)

    Mündel, Toby; Carter, James M; Wilkinson, David M; Jones, David A

    2016-01-01

    The purpose of this study was to compare three of the most commonly used methods of core temperature (Tcore) measurement during cycling under different environmental conditions as there are practical problems associated with each method and, sometimes, uncertainty as to which is the appropriate measure. Eight trained males (VO2 max: 60 ± 7 ml kg(-1) min(-1)) completed two 60-min cycling trials at ~70% VO2 max at 20°C (MOD) and 35°C (HOT). Measures of Tcore were made every 5 min with oesophageal (Toes) and rectal (Trec) thermistors and of the gastro-intestinal tract temperature (Tgi ) with a temperature-sensitive disposable radio pill. During MOD Toes initially plateaued after 10 min, Tgi after 25 min and Trec after 50 min, whereas during HOT these times had increased to 25 min for Toes and 55 min for both Tgi and Trec. Toes consistently provided lower readings than Trec (0·24-0·26°C) and Tgi (0·26-0·28°C) with Tgi and Trec similar (0·02°C). Readings for Tgi displayed closer agreement with Trec (ICC = 0·92) than Toes (ICC = 0·86) with less agreement between Trec and Toes (ICC = 0·84). 95% of all Tgi readings were within ±0·5°C of Trec and within ±0·6°C of Toes with 95% of all Toes readings being within ±0·7°C of Trec . These results demonstrate distinct response times, absolute values and agreement between Tcore measured at different body locations under different ambient conditions. Implications and considerations are discussed.

  19. 質問紙法で推定した最大酸素摂取量の運動種目の違いによる妥当性の検討 : 中高齢者を対象として

    OpenAIRE

    沼尾, 成晴; 田中, 喜代次; 林, 容市; 中垣内, 真樹; 藤村, 透子; 佐藤, 進; 出村, 慎一

    2004-01-01

    Although a self-report questionnaire has already been developed to evaluate maximal oxygen uptake (Vo_2max) indirectly, it is still unclear whether it can accurately predict Vo_2max, especially in middle-aged and older adults. The purpose of this study was to compare differences between directly measured Vo_2max using a cycle ergometer protocol and Vo_2max predicted by a self-report questionnaire. One hundred forty subjects (aged 61.3±8.2) were divided into four groups: control group (group C...

  20. CYCLING EFFICIENCY IN TRAINED MALE AND FEMALE COMPETITIVE CYCLISTS

    Directory of Open Access Journals (Sweden)

    James Hopker

    2010-06-01

    Full Text Available The aim of this study was to examine differences in cycling efficiency between competitive male and female cyclists. Thirteen trained male (mean ± SD: 34 ± 8 yr, 74.1 ± 6.0 kg, Maximum Aerobic Power (MAP 414 ± 40 W, VO2max 61.3 ± 5.4 ml·kg-1·min-1 and 13 trained female (34 ± 9 yr, 60.1 ± 5.2 kg, MAP 293 ± 22 W, VO2max 48.9 ± 6.1 ml·kg-1·min-1 competitive cyclists completed a cycling test to ascertain their gross efficiency (GE. Leg and lean leg volume of all cyclists was also measured. Calculated GE was significantly higher in female cyclists at 150W (22.5 ± 2.1 vs 19.9 ± 1. 8%; p < 0.01 and 180W (22.3 ± 1.8 vs 20.4 ± 1.5%; p = 0.01. Cadence was not significantly different between the groups (88 ± 6 vs 91 ± 5 rev·min-1. Lean leg volume was significantly lower for female cyclists (4.04 ± 0.5 vs 5.51 ± 0.8 dm3; p < 0.01 and was inversely related to GE in both groups at 150 and 180W (r = -0.59 and -0.58; p < 0.05. Lean leg volume was shown to account for the differences in GE between the males and females. During an "unloaded" pedalling condition, male cyclists had a significantly higher O2 cost than female cyclists (1.0 ± 0.1 vs 0.7 ± 0.1 L·min-1; p < 0.01, indicative of a greater non-propulsive cost of cycling. These results suggest that differences in efficiency between trained male and female cyclists can be partly accounted for by sex-specific variation in lean leg volume

  1. Aerothermodynamic cycle analysis of a dual-spool, separate-exhaust turbofan engine with an interstage turbine burner

    Science.gov (United States)

    Liew, Ka Heng

    This study focuses on a specific engine, i.e., a dual-spool, separate-flow turbofan engine with an Interstage Turbine Burner (ITB). This conventional turbofan engine has been modified to include a secondary isobaric burner, i.e., ITB, in a transition duct between the high-pressure turbine and the low-pressure turbine. The preliminary design phase for this modified engine starts with the aerothermodynamics cycle analysis is consisting of parametric (i.e., on-design) and performance ( i.e., off-design) cycle analyses. In parametric analysis, the modified engine performance parameters are evaluated and compared with baseline engine in terms of design limitation (maximum turbine inlet temperature), flight conditions (such as flight Mach condition, ambient temperature and pressure), and design choices (such as compressor pressure ratio, fan pressure ratio, fan bypass ratio etc.). A turbine cooling model is also included to account for the effect of cooling air on engine performance. The results from the on-design analysis confirmed the advantage of using ITB, i.e., higher specific thrust with small increases in thrust specific fuel consumption, less cooling air, and less NOx production, provided that the main burner exit temperature and ITB exit temperature are properly specified. It is also important to identify the critical ITB temperature, beyond which the ITB is turned off and has no advantage at all. With the encouraging results from parametric cycle analysis, a detailed performance cycle analysis of the identical engine is also conducted for steady-state engine performance prediction. The results from off-design cycle analysis show that the ITB engine at full throttle setting has enhanced performance over baseline engine. Furthermore, ITB engine operating at partial throttle settings will exhibit higher thrust at lower specific fuel consumption and improved thermal efficiency over the baseline engine. A mission analysis is also presented to predict the fuel

  2. Does Standing on a Cycle-ergometer, Towards the Conclusion of a Graded Exercise Test, Yield Cardiorespiratory Values Equivalent to Treadmill Testing?

    Science.gov (United States)

    Mitchell, Joshua; Kist, William B; Mears, Kendall; Nalls, Jesse; Ritter, Kyle

    Graded exercise testing (GXT), per a cycle-ergometer (CE), offers safety and monitoring advantages over treadmill (TM) GXT. Unfortunately, CE-VO2max and some other cardiorespiratory (CR) variables are frequently lower than TM-GXT values. It has been difficult to compare TM and CE-GXT values. However, it was hypothesized that standing towards the conclusion of the CE-GXT (Stand-CE) might increase CE values to those equal to TM-GXT. If Stand-CE and TM-GXT CR values were equal, Stand-CE-GXT could become the method of choice for GXT for the general population. The purpose of this investigation was to investigate the effect of Stand-CE on CR variables. An intentionally diverse sample (N = 34, 24 males and 10 females, aged 18-54 y, with VO2max values 25-76 ml/kg/min) representing the "apparently healthy" general population participated. Volunteers completed two GXT trials, one per TM (Bruce protocol) and the other per a MET-TM-matched CE-GXT where initially seated participants stood and pedaled after their respiratory exchange ratio (RER) reached 1.0. Eighteen participants underwent a third MET-TM-matched trial where they remained seated throughout GXT (Sit-CE). Trials were counter-balanced with at least 48 h between GXT. There were significant statistical differences (p test (N = 34) on the following variables: VEmax (TM = 115 ± 24.4 l/min, Stand-CE = 99.4 ± 28.1), VCO2max (TM = 4.26 ± 0.9 l/min, Stand-CE = 3.56 ± 0.84), VO2max (TM = 44.9 ± 9.1 ml/kg/min, Stand-CE = 39.3 ± 9.0), METSmax (TM = 12.8 ± 2.6 METS, Stand-CE = 11.2 ± 2.5), and HRmax (TM = 175 ± 13 bpm, Stand-CE = 166 ± 12). One-way repeated measures ANOVA (N = 18) demonstrated no statistical differences among all trials: VEmax (TM = 112.8 ± 25.3 l/min, Stand-CE = 102.3 ± 25.2, Sit-CE = 107.3 ± 33.1), VCO2max (TM = 4.17 ± 0.99 l/min, Stand-CE = 3.62 ± 0.80, Sit-CE = 3.55 ± 0.83), VO2max (TM = 47.1 ± 9.8 ml/kg/min, Stand-CE = 42.0 ± 9.0, Sit-CE = 43.3 ± 8.9), METSmax (TM = 13.5 ± 2.8 METS

  3. Performance Analysis of a Reciprocating Piston Expander and a Plate Type Exhaust Gas Recirculation Boiler in a Water-Based Rankine Cycle for Heat Recovery from a Heavy Duty Diesel Engine

    OpenAIRE

    Gunnar Latz; Olof Erlandsson; Thomas Skåre; Arnaud Contet; Sven Andersson; Karin Munch

    2016-01-01

    The exhaust gas in an internal combustion engine provides favorable conditions for a waste-heat recovery (WHR) system. The highest potential is achieved by the Rankine cycle as a heat recovery technology. There are only few experimental studies that investigate full-scale systems using water-based working fluids and their effects on the performance and operation of a Rankine cycle heat recovery system. This paper discusses experimental results and practical challenges with a WHR system when u...

  4. Structural protein alterations to resistance and endurance cycling exercise training.

    Science.gov (United States)

    Parcell, Allen C; Woolstenhulme, Mandy T; Sawyer, Robert D

    2009-03-01

    The muscle cytoskeleton is necessary for the effective transmission of forces generated by actin-myosin interactions. We have examined the impact of muscle force and exercise volume on the cytoskeleton by measuring desmin and dystrophin content in human skeletal muscle after 12 weeks of progressive resistance or endurance cycle training. Muscle biopsies of the vastus lateralis were obtained before and after training. Desmin and dystrophin content was determined using immunoblotting techniques. After resistance training, desmin content increased 82 +/- 18% (p < 0.05), whereas there was no change in desmin content with endurance cycling. Dystrophin content did not change in either group. One-repetition maximum and VO2max increased (p < 0.05) in the resistance and endurance groups, respectively. These data demonstrate that a high-tension stimulus impacts the cytoskeleton in contrast to high-volume concentric contractions. The tensile loading and eccentric components of resistance training are implicated in desmin alterations. Indeed, the functional improvements resulting from resistance training may be related in part to the mechanical integration provided by the desmin protein.

  5. Parametric (On-Design) Cycle Analysis for a Separate-Exhaust Turbofan Engine With Interstage Turbine Burner

    Science.gov (United States)

    Liew, K. H.; Urip, E.; Yang, S. L.; Siow, Y. K.; Marek, C. J.

    2005-01-01

    Today s modern aircraft is based on air-breathing jet propulsion systems, which use moving fluids as substances to transform energy carried by the fluids into power. Throughout aero-vehicle evolution, improvements have been made to the engine efficiency and pollutants reduction. The major advantages associated with the addition of ITB are an increase in thermal efficiency and reduction in NOx emission. Lower temperature peak in the main combustor results in lower thermal NOx emission and lower amount of cooling air required. This study focuses on a parametric (on-design) cycle analysis of a dual-spool, separate-flow turbofan engine with an Interstage Turbine Burner (ITB). The ITB considered in this paper is a relatively new concept in modern jet engine propulsion. The ITB serves as a secondary combustor and is located between the high- and the low-pressure turbine, i.e., the transition duct. The objective of this study is to use design parameters, such as flight Mach number, compressor pressure ratio, fan pressure ratio, fan bypass ratio, and high-pressure turbine inlet temperature to obtain engine performance parameters, such as specific thrust and thrust specific fuel consumption. Results of this study can provide guidance in identifying the performance characteristics of various engine components, which can then be used to develop, analyze, integrate, and optimize the system performance of turbofan engines with an ITB. Visual Basic program, Microsoft Excel macrocode, and Microsoft Excel neuron code are used to facilitate Microsoft Excel software to plot engine performance versus engine design parameters. This program computes and plots the data sequentially without forcing users to open other types of plotting programs. A user s manual on how to use the program is also included in this report. Furthermore, this stand-alone program is written in conjunction with an off-design program which is an extension of this study. The computed result of a selected design

  6. Individual heat stress response

    NARCIS (Netherlands)

    Havenith, G.

    1997-01-01

    In 5 experiments, heterogeneous subject groups (large variations in _VO2 max, regular daily activity level, mass, body surface area (AD), % body fat, and AD/mass ratio) were tested for their physiological response while exercising on a cycle ergometer at a relative (45% _VO2 max; REL) or an absolute

  7. THE ROLE OF AEROBIC CAPACITY IN HIGH-INTENSITY INTERMITTENT EFFORTS IN ICE-HOCKEY

    Directory of Open Access Journals (Sweden)

    A. Stanula

    2014-08-01

    Full Text Available The primary objective of this study was to determine a relationship between aerobic capacity ( ·VO2max and fatigue from high-intensity skating in elite male hockey players. The subjects were twenty-four male members of the senior national ice hockey team of Poland who played the position of forward or defence. Each subject completed an on-ice Repeated-Skate Sprint test (RSS consisting of 6 timed 89-m sprints, with 30 s of rest between subsequent efforts, and an incremental test on a cycle ergometer in the laboratory, the aim of which was to establish their maximal oxygen uptake ( ·VO2max. The analysis of variance showed that each next repetition in the 6x89 m test was significantly longer than the previous one (F5,138=53.33, p<0.001. An analysis of the fatigue index (FI calculated from the times recorded for subsequent repetitions showed that the value of the FI increased with subsequent repetitions, reaching its maximum between repetitions 5 and 6 (3.10±1.16%. The total FI was 13.77±1.74%. The coefficient of correlation between ·VO2max and the total FI for 6 sprints on the distance of 89 m (r =–0.584 was significant (p=0.003. The variance in the index of players’ fatigue in the 6x89 m test accounted for 34% of the variance in ·VO2max. The 6x89 m test proposed in this study offers a high test-retest correlation coefficient (r=0.78. Even though the test is criticized for being too exhaustive and thereby for producing highly variable results it still seems that it was well selected for repeated sprint ability testing in hockey players.

  8. Experimental study on relationship among Fatmax,aerobic endurance and RPE%最大脂肪代谢强度与有氧耐力及RPE关系的实验研究

    Institute of Scientific and Technical Information of China (English)

    宋伟; 胡柏平

    2013-01-01

    In order to analyze the relationships among Fatmax, VO2max 、ILT and Rating of Perceived Exertion (RPE) ,eight subjects are selected to performed a graded exercise test to exhaustion on a cycle-ergometer. Fatmax, VO2max ILT, RPE are tested, and their correlations are analyzed. The experiment result shows that the RPE of ILT and Fatmax are 9. 4 ± 2. 3 and 13. 5 ± 2. 0(P<0. 05) respectively and Fatmax appears earlier. The relativities between Fatmax, VO2max and ILT are conformed. Such condusions can be made, the RPE can effectively determine Fatmax and ILT. Exercise intensity should be increased properly in fat reducing sports to the person with good cardiopulmonary function and aerobic metabolism ability.%为研究最大脂肪代谢强度(Fatmax)、最大摄氧量(VO2max)、乳酸阈强度(ILT)以及主观体力感觉(RPE)之间的关系,选择8名受试者在功率自行车上进行一次递增负荷的力竭运动,测试指标Fatmax、VO2max、ILT和RPE,并进行相关性分析.结果显示:达到Fatmax、ILT的RPE分别为9.4±2.3和13.5±2.0(P<0.05),Fatmax的出现要早于ILT,Fatmax与VO2max、ILT都存在显著的相关性.结论表明,应用RPE可以有效判断Fatmax和ILT,对于心肺功能良好、有氧代谢能力较佳的体育健身者,在减脂运动中可以适当提高运动负荷.

  9. Effect of sex and menstrual cycle in women on starting speed, anaerobic endurance and muscle power.

    Science.gov (United States)

    Wiecek, M; Szymura, J; Maciejczyk, M; Cempla, J; Szygula, Z

    2016-03-01

    The aim of our study was to compare the indicators of starting speed, anaerobic endurance and power in women as well as men, and to investigate whether the values of these indicators differ in women during the follicular and luteal phases of the menstrual cycle. The studied group included 16 men and 16 women. The subjects performed the 20-second maximal cycling sprint test. The men performed the test twice at 14-day intervals. The women undertook the test 4 times: twice during the middle of follicular phase and twice in the middle of luteal phase in separate menstrual cycles. Hormonal changes during the menstrual cycle do not influence anaerobic performance, starting speed or anaerobic endurance in women. Anaerobic performance in men is higher than in women with similar aerobic performance expressed as VO2max/LBM (lean body mass). A lower power decrease with time was noted for women than men, with a similar time of maintaining power in both groups. This is evidence of women's better anaerobic endurance compared to men. At the same time, the men had significantly better starting speed rates than women.

  10. Maximum Oxygen Uptake and Post-Exercise Recovery in Professional Road Cyclists

    Directory of Open Access Journals (Sweden)

    Rutkowski Łukasz

    2016-09-01

    Full Text Available Purpose. The aim was to investigate the relationship between aerobic fitness as ascribed by maximum oxygen uptake (VO2max and post-exercise recovery after incremental exercise to volitional exhaustion.

  11. Menstrual cycle phase effects free testosterone responses to prolonged aerobic exercise.

    Science.gov (United States)

    Lane, A R; O'Leary, C B; Hackney, A C

    2015-09-01

    Research has shown that total testosterone (tT) levels in women increase acutely during a prolonged bout of aerobic exercise. Few studies, however, have considered the impact of the menstrual cycle phase on this response or have looked at the biologically active free testosterone (fT) form responses. Therefore, this study examined the fT concentration response independently and as a percentage (fT%) of tT to prolonged aerobic exercise during phases of the menstrual cycle with low estrogen-progesterone (L-EP; i.e., follicular phase) and high estrogen-progesterone (H-EP; i.e., luteal phase). Ten healthy, recreationally trained, eumennorrheic women (X ± SD: age = 20 ± 2 y, mass = 58.7 ± 8.3 kg, body fat = 22.3 ± 4.9 %, VO(2max) = 50.7 ± 9.0 ml/kg/min) participated in a laboratory based study and completed a 60-minute treadmill run during the L-EP and H-EP menstrual phases at ~70% of VO(2max). Blood was drawn prior to (PRE), immediately after (POST) and following 30 minutes of recovery (30POST) with each 60-minute run. During H-EP, there was a significant increase in fT concentrations from PRE to POST (p exercise sampling time. There was, however, a main effect for exercise where fT% POST was a greater proportion of tT than at PRE (p exercise bout; specifically, there being higher levels under H-EP conditions. This suggests more biologically active T is available during exercise in this phase. This response may be a function of the higher core temperatures found with H-EP causing greater sex hormone binding protein release of T, or could be a function of greater degrees of glandular production. Further work is warranted to elucidate the mechanism of this occurrence. It is recommended that researchers examining T responses to exercise in women look at both tT and fT forms in order to have an accurate endocrine assessment in women.

  12. Transferability of running and cycling training zones in triathletes: implications for steady-state exercise.

    Science.gov (United States)

    Carey, Daniel G; Tofte, Courtney; Pliego, German J; Raymond, Robert L

    2009-01-01

    The primary objective of this study was to determine whether physiological measurements obtained from one mode of testing and training could be applied to another mode, as in prescribing heart rate (HR) zone training from cyling to running. Secondary objectives were 1) to assess the validity of applying data from incremental testing to steady-state exercise, and 2) to compare breakpoint in respiratory rate (RR) with the conventional method of anaerobic threshold (AT) breakpoint, the ventilatory equivalent for oxygen VE/VO2). Sixteen experienced triathletes performed VO2max testing on a cycle ergometer (CE) and treadmill (TM). In addition, a 30-minute time trial (TT) was performed on a CE. No significant differences were observed between modes of testing for VO2max (CE = 68.4 +/- 11.1 mlxkgxmin, TM = 69.0 +/- 13.2 mlxkgxmin), maximum HR (CE = 177.1 +/- 6.1 bpm, TM = 178.1 +/- 7.4 bpm), or AT (CE AT HR = 153.9 +/- 10.5 bpm, TM AT HR = 157.0 +/- 9.5 bpm). Although the mean difference in AT HR was small (3.1 bpm), a small correlation coefficient (0.321) between the AT for the 2 testing modes resulted in a large total error (TE = 12.1 bpm), indicating limited practical application of training zones between modes of testing. Mean TT HR and mean TT RR were significantly greater than mean AT HR (159.4 +/- 8.9 vs. 153.9 +/- 10.5 bpm) and mean AT RR (37.8 +/- 6.0 vs. 32.4 +/- 3.2 breaths per minute) because of significant "drift" in these 2 variables over time, whereas TT watts and AT watts were not significantly different (249.1 +/- 47.8 vs. 240.6 +/- 71.1 W). Finally, a significant difference and large TE (9.0 bpm) betweenVE/VO2 AT HR and the RR AT HR (153.9 +/- 10.5 and 158.4 +/- 10.0 bpm) may preclude the practical use of the RR breakpoint. From the results of this study, it is recommended that the triathlete perform sport-specific testing to assess training zones for cycling and running. In addition, because both HR and RR "drift" upward with steady-state exercise, AT

  13. A new approach to assessing maximal aerobic power in children: the Odense School Child Study.

    Science.gov (United States)

    Hansen, H S; Froberg, K; Nielsen, J R; Hyldebrandt, N

    1989-01-01

    In two experiments maximal aerobic power (VO2max) calculated from maximal mechanical power (Wmax) was evaluated in 39 children aged 9-11 years. A maximal multi-stage cycle ergometer exercise test was used with an increase in work load every 3 min. In the first experiment oxygen consumption was measured in 18 children during each of the prescribed work loads and a correction factor was calculated to estimate VO2max using the equation VO2max = 12.Wmax + 5.weight. An appropriate increase in work rate based on height was determined for boys (0.16 W.cm-1) and girls (0.15 W.cm-1) respectively. In the second experiment 21 children performed a maximal cycle ergometer exercise test twice. In addition to the procedure in the first experiment a similar exercise test was performed, but without measurement of oxygen uptake. Calculated VO2max correlated significantly (p less than 0.01) with those values measured in both boys (r = 0.90) and girls (r = 0.95) respectively, and the standard error of estimation for VO2max (calculated) on VO2max (measured) was less than 3.2%. Two expressions of relative work load (%VO2max and %Wmax) were established and found to be closely correlated. The relative work load in %VO2max could be predicted from the relative work load in %Wmax with an average standard error of 3.8%. The data demonstrate that calculated VO2max based on a maximal multi-stage exercise test provides an accurate and valid estimate of VO2max.

  14. Low cadence interval training at moderate intensity does not improve cycling performance in highly trained veteran cyclists

    Directory of Open Access Journals (Sweden)

    Morten eKristoffersen

    2014-01-01

    Full Text Available Purpose: The aim of the present study was to investigate effects of low cadence training at moderate intensity on aerobic capacity, cycling performance, gross efficiency, freely chosen cadence and leg strength in veteran cyclists. Method: Twenty-two well trained veteran cyclists (age: 47 ±6 years, maximal oxygen consumption (VO2max: 57.9 ±3.7 ml. kg-1. min-1 were randomized into two groups, a low cadence training group and a freely chose cadence training group. Respiratory variables, power output, cadence and leg strength were tested before and after a 12 weeks training intervention period. The low cadence training group performed 12 weeks of moderate (73-82 % of maximal heart rate (HRmax interval training (5 x 6 min with a cadence of 40 revolutions per minute (rpm two times a week, in addition to their usual training. The freely chosen cadence group added 90 minutes of training at freely chosen cadence at moderate intensity. Results: No significant effects of the low cadence training on aerobic capacity, cycling performance, power output, cadence, gross efficiency or leg strength was found. The freely chosen cadence group significantly improved both VO2max (58.9±2.4 vs. 62.2±3.2 ml. kg-1. min-1, VO2 consumption at lactate threshold (49.4 ±3.8 vs. 51.8±3.5 ml. kg-1. min-1 and during the 30 min performance test (52.8±3.0 vs. 54.7±3.5 ml. kg-1. min-1, and power output at lactate threshold (284 ±47 vs. 294 ±48 W and during the 30 min performance test (284±42 vs. 297±50 W. Conclusion: Twelve weeks of low cadence (40 rpm interval training at moderate intensity (73-82 % of HRmax twice a week does not improve aerobic capacity, cycling performance or leg strength in highly trained veteran cyclists. However, adding training at same intensity (% of HRmax and duration (90 minutes weekly at freely chosen cadence seems beneficial for performance and physiological adaptations.

  15. A Comparison between Alpine Skiing, Cross-Country Skiing and Indoor Cycling on Cardiorespiratory and Metabolic Response.

    Science.gov (United States)

    Stöggl, Thomas; Schwarzl, Christoph; Müller, Edith E; Nagasaki, Masaru; Stöggl, Julia; Scheiber, Peter; Schönfelder, Martin; Niebauer, Josef

    2016-03-01

    Since physical inactivity especially prevails during winter months, we set out to identify outdoor alternatives to indoor cycling (IC) by comparing the metabolic and cardiorespiratory responses during alpine skiing (AS), cross-country skiing (XCS) and IC and analyse the effects of sex, age and fitness level in this comparison. Twenty one healthy subjects performed alpine skiing (AS), cross-country skiing (XCS), and IC. Oxygen uptake (VO2), total energy expenditure (EE), heart rate (HR), lactate, blood glucose and rate of perceived exertion (RPE) were determined during three 4-min stages of low, moderate and high intensity. During XCS and IC VO2max and EE were higher than during AS. At least 2½ hours of AS are necessary to reach the same EE as during one hour of XCS or IC. HR, VO2, lactate, and RPEarms were highest during XCS, whereas RPEwhole-body was similar and RPElegs lower than during AS and IC, respectively. Weight adjusted VO2 and EE were higher in men than in women while fitness level had no effect. Male, fit and young participants were able to increase their EE and VO2 values more pronounced. Both AS and XCS can be individually tailored to serve as alternatives to IC and may thus help to overcome the winter activity deficit. XCS was found to be the most effective activity for generating a high EE and VO2 while AS was the most demanding activity for the legs. Key pointsDuring cross-country skiing and indoor cycling VO2max and energy expenditure were higher than during alpine skiingApproximately 2½ hours of alpine skiing are necessary to reach the same energy expenditure of one hour of cross-country skiing or indoor cycling.Alpine skiing and cross-country skiing can be individually tailored to serve as sports alternatives in winter to activity deficit.By applying different skiing modes as parallel ski steering, carving long radii and short turn skiing, metabolic and cardiorespiratory response can be increased during alpine skiing.Male, fit and young

  16. A comparison of cytokine responses during prolonged cycling in normal and hot environmental conditions

    Directory of Open Access Journals (Sweden)

    Ludmila M Cosio-Lima

    2011-01-01

    Full Text Available Ludmila M Cosio-Lima, Bhargav V Desai, Petra B Schuler, Lesley Keck, Logan ScheelerDepartment of Health, Leisure, and Exercise Science, University of West Florida, Pensacola, FL, USAPurpose: Components of immune function are affected by physical activity in an adverse environment. The purpose of this study was to compare plasma differences in inflammatory cytokines including tumor necrosis factor α (TNF-α and interleukin 6 (IL-6, in addition to the stress hormone cortisol, during prolonged cycling under normal and hot environmental conditions in elite cyclists.Methods and design: Six trained elite male cyclists (27 ± 8 years; 75.5 ± 4 kg; maximum oxygen uptake [VO2max] = 66 ± 6 mL/kg/min, mean ± SD. The cyclists biked for 2.5 h at their prescribed 60% maximum exercise workload (Wmax or 75% VO2max either in an environmental chamber set at 15°C and 40% relative humidity (NEUTRAL or at 35°C and 40% relative humidity (HOT. The cyclists were given 4 mL of water/kg body weight every 15 min under both conditions.Results: Total cortisol concentrations were elevated (P < 0.05 immediately postexercise and 12 h postexercise in both the NEUTRAL and HOT conditions. TNF-α concentrations were only significantly (P = 0.045 elevated postexercise in HOT conditions. During the HOT conditions, a significant (P = 0.006 and 0.007, respectively difference in IL-6 was seen immediately after and 12 h postexercise. During the NEUTRAL condition, IL-6 was only significantly elevated postexercise (P < 0.05.Conclusions: Heat exposure during a long bout of exercise is sufficient to elicit stress response in elite cyclists. However, the degree of release of anti-inflammatory and proinflammatory cytokines might be related to several factors that include the athlete’s fitness level, hydration status, exercise intensity, and length of exposure to hot environments.Keywords: cytokines, inflammation, heat, exercise, performance 

  17. PHYSIOLOGICAL EFFECTS OF AN ULTRA-CYCLE RIDE IN AN AMATEUR ATHLETE- A CASE REPORT

    Directory of Open Access Journals (Sweden)

    Günther Mitterbauer

    2002-03-01

    Full Text Available The physiological effects of ultraendurance exercise are poorly investigated. The present case report describes the exercise intensity of ultraendurance cycling and its physiological impacts on various organ functions in an amateur cyclist performing the Ötztal Radmarathon twice en bloque in a circuit of 2 identical laps (distance 460 km; cumulative altitude difference 11,000 m. In a pre-race laboratory test the athlete's performance capacity was measured as the maximal aerobic power (VO2max= 70 ml.kg-1.min-1, a maximal power output (5.7 W.kg-1 and lactate threshold of 89%. The overall intensity during the ride was moderate (HRmean = 131 b.min-1; %HRmax = 0.71 and significantly declined during the course of the race. Extensive biochemical laboratory testing performed pre- and post-race excluded major exercise-induced organ disturbances. For further confirmation and better understanding of the physiological effects of ultra-cycle events future studies of larger athlete populations are required.

  18. A PRACTICAL MODEL OF LOW-VOLUME HIGH-INTENSITY INTERVAL TRAINING INDUCES PERFORMANCE AND METABOLIC ADAPTATIONS THAT RESEMBLE 'ALL-OUT' SPRINT INTERVAL TRAINING

    Directory of Open Access Journals (Sweden)

    Mahdi Bayati

    2011-09-01

    Full Text Available Recently, a novel type of high-intensity interval training known as sprint interval training has demonstrated increases in aerobic and anaerobic performance with very low time commitment. However, this type of training program is unpractical for general populations. The present study compared the impact of a low-volume high-intensity interval training to a "all-out" sprint interval training. Twenty-four active young males were recruited and randomized into three groups: (G1: 3-5 cycling bouts × 30-s all-out with 4 min recovery; G2: 6- 10 cycling bouts × 125% Pmax with 2 min recovery and a non-trained control group. They all performed a VO2max test, a time to exhaustion at Pmax (Tmax and a Wingate test before and after the intervention. Capillary blood lactate was taken at rest, 3, and 20 min after the Wingate trial. Training was performed 3 sessions per week for 4 weeks. In G1, significant improvements (p < 0.05 following training were found in VO2max (9.6%, power at VO2max (12.8%, Tmax (48.4%, peak power output (10.3% and mean power output (17.1%. In G2, significant improvements following training were found in VO2max (9.7%, power at VO2max (16.1%, Tmax (54.2%, peak power output (7.4%; p < 0.05, but mean power output did not change significantly. Blood lactate recovery (20th min significantly decreased in G1 and G2 when compared with pre-testing and the CON group (p < 0.05. In conclusion, the results of the current study agree with earlier work demonstrating the effectiveness of 30-s all-out training program to aerobic and anaerobic adaptations. Of substantial interest is that the low volume high intensity training provides similar results but involves only half the intensity with double the repetitions

  19. Determinants of maximal oxygen uptake in severe acute hypoxia

    DEFF Research Database (Denmark)

    Calbet, J A L; Boushel, Robert Christopher; Rådegran, G

    2003-01-01

    To unravel the mechanisms by which maximal oxygen uptake (VO2 max) is reduced with severe acute hypoxia in humans, nine Danish lowlanders performed incremental cycle ergometer exercise to exhaustion, while breathing room air (normoxia) or 10.5% O2 in N2 (hypoxia, approximately 5,300 m above sea...... level). With hypoxia, exercise PaO2 dropped to 31-34 mmHg and arterial O2 content (CaO2) was reduced by 35% (P ..., as reflected by the higher alveolar-arterial O2 difference in hypoxia (P stroke VOlume (P

  20. Determination of Aerobic Power Through a Specific Test for Taekwondo - A Predictive Equation Model

    Directory of Open Access Journals (Sweden)

    Rocha Fernando P.S.

    2016-12-01

    Full Text Available Our aim was to verify the concurrent validity of a maximal taekwondo specific test (TST to predict VO2max through an explanatory model. Seventeen elite male taekwondo athletes (age: 17.59 ± 4.34 years; body height: 1.72 ± 6.5 m; body mass: 61.3 ± 8.7 kg performed two graded maximal exercise tests on different days: a 20 m multistage shuttle run test (SRT and an incremental TST. We recorded test time, VO2max, ventilation, a heart rate and time to exhaustion. Significant differences were found between observed and estimated VO2max values [F (2, 16 = 5.77, p < 0.01]; post-hoc subgroup analysis revealed the existence of significant differences (p = 0.04 between the estimated VO2max value in the SRT and the observed value recorded in the TST (58.4 ± 6.4 ml/kg/min and 52.6 ± 5.2 ml/kg/min, respectively. Our analysis also revealed a moderate correlation between both testing protocols regarding VO2max (r = 0.70; p = 0.005, test time (r = 0.77; p = 0.02 and ventilation (r = 0.69; p = 0.03. There was no proportional bias in the mean difference (t = -1.04; p = 0.313, and there was a level of agreement between both tests. An equation/model was used to estimate VO2max during the TST based on the mean heart rate, test time, body height and mass, which explained 74.3% of the observed VO2max variability. A moderate correlation was found between the observed and predicted VO2max values in the taekwondo TST (r = 0.74, p = 0.001. Our results suggest that an incremental specific test estimates VO2max of elite taekwondo athletes with acceptable concurrent validity.

  1. The effects of breathing a helium-oxygen gas mixture on maximal pulmonary ventilation and maximal oxygen consumption during exercise in acute moderate hypobaric hypoxia.

    Science.gov (United States)

    Ogawa, Takeshi; Calbet, Jose A L; Honda, Yasushi; Fujii, Naoto; Nishiyasu, Takeshi

    2010-11-01

    To test the hypothesis that maximal exercise pulmonary ventilation (VE max) is a limiting factor affecting maximal oxygen uptake (VO2 max) in moderate hypobaric hypoxia (H), we examined the effect of breathing a helium-oxygen gas mixture (He-O(2); 20.9% O(2)), which would reduce air density and would be expected to increase VE max. Fourteen healthy young male subjects performed incremental treadmill running tests to exhaustion in normobaric normoxia (N; sea level) and in H (atmospheric pressure equivalent to 2,500 m above sea level). These exercise tests were carried out under three conditions [H with He-O(2), H with normal air and N] in random order. VO2 max and arterial oxy-hemoglobin saturation (SaO(2)) were, respectively, 15.2, 7.5 and 4.0% higher (all p max, 171.9 ± 16.1 vs. 150.1 ± 16.9 L/min; VO2 max, 52.50 ± 9.13 vs. 48.72 ± 5.35 mL/kg/min; arterial oxyhemoglobin saturation (SaO(2)), 79 ± 3 vs. 76 ± 3%). There was a linear relationship between the increment in VE max and the increment in VO2 max in H (r = 0.77; p VO2 max, both groups showed increased VE max and SaO(2) in H with He-O(2), but VO2 max was increased only in the high VO2 max group. These findings suggest that in acute moderate hypobaric hypoxia, air-flow resistance can be a limiting factor affecting VE max; consequently, VO2 max is limited in part by VE max especially in subjects with high VO2 max.

  2. The effects of low and high glycemic index foods on exercise performance and beta-endorphin responses

    Directory of Open Access Journals (Sweden)

    Nikolaidis Michalis G

    2011-10-01

    Full Text Available Abstract Τhe aim of this study was to examine the effects of the consumption of foods of various glycemic index values on performance, β-endorphin levels and substrate (fat and carbohydrate utilization during prolonged exercise. Eight untrained healthy males underwent, in a randomized counterbalanced design, three experimental conditions under which they received carbohydrates (1.5 gr. kg-1 of body weight of low glycemic index (LGI, high glycemic index (HGI or placebo. Food was administered 30 min prior to exercise. Subjects cycled for 60 min at an intensity corresponding to 65% of VO2max, which was increased to 90% of VO2max, then they cycled until exhaustion and the time to exhaustion was recorded. Blood was collected prior to food consumption, 15 min prior to exercise, 0, 20, 40, and 60 min into exercise as well as at exhaustion. Blood was analyzed for β-endorphin, glucose, insulin, and lactate. The mean time to exhaustion did not differ between the three conditions (LGI = 3.2 ± 0.9 min; HGI = 2.9 ± 0.9 min; placebo = 2.7 ± 0.7 min. There was a significant interaction in glucose and insulin response (P P

  3. Performance Analysis of a Reciprocating Piston Expander and a Plate Type Exhaust Gas Recirculation Boiler in a Water-Based Rankine Cycle for Heat Recovery from a Heavy Duty Diesel Engine

    Directory of Open Access Journals (Sweden)

    Gunnar Latz

    2016-06-01

    Full Text Available The exhaust gas in an internal combustion engine provides favorable conditions for a waste-heat recovery (WHR system. The highest potential is achieved by the Rankine cycle as a heat recovery technology. There are only few experimental studies that investigate full-scale systems using water-based working fluids and their effects on the performance and operation of a Rankine cycle heat recovery system. This paper discusses experimental results and practical challenges with a WHR system when utilizing heat from the exhaust gas recirculation system of a truck engine. The results showed that the boiler’s pinch point necessitated trade-offs between maintaining adequate boiling pressure while achieving acceptable cooling of the EGR and superheating of the water. The expander used in the system had a geometric compression ratio of 21 together with a steam outlet timing that caused high re-compression. Inlet pressures of up to 30 bar were therefore required for a stable expander power output. Such high pressures increased the pump power, and reduced the EGR cooling in the boiler because of pinch-point effects. Simulations indicated that reducing the expander’s compression ratio from 21 to 13 would allow 30% lower steam supply pressures without adversely affecting the expander’s power output.

  4. Physiological Responses during Cycling With Oval Chainrings (Q-Ring and Circular Chainrings

    Directory of Open Access Journals (Sweden)

    Alfredo Cordova

    2014-06-01

    Full Text Available The aim of this study was to compare the physiological responses of cyclists using round (C-ring or oval (Q-ring chainrings during an incremental test until exhaustion. Following a randomized design, fourteen male elite cyclists [age (mean ± SD: 21.1 ± 2.1 yr; VO2max: 78.5 ± 5.3 mL·kg-1min-1] performed two incremental maximal tests separated by 48 h (one with C-rings, the other with Q-rings. Starting at 100 W, the workload was increased by 25 W every 3 min until volitional exhaustion. Maximal heart rate, power output and oxygen consumption were compared. Blood lactate was monitored throughout the test. After the incremental test, 4 intermittent 20-s maximal sprints with a 60-s recovery period in between were performed. Maximal isometric voluntary contractions were performed at rest and immediately after each 20-s maximal sprint, and the force and EMG RMS amplitude were recorded from the vastus medialis and vastus lateralis muscles. For the incremental exercise test, no significant differences were found in the maximal power output (P=0.12, oxygen consumption (P=0.39, and heart rate (P=0.32 between Q-rings and C-rings. Throughout the incremental test, lactate levels were comparable when using both the C-rings and Q-rings (P=0.47. During the short sprints, power output was 2.5–6.5% greater for Q-rings than for C-rings (P=0.22. The decline in EMG RMS amplitude observed during the incremental tests was comparable for Q-rings and C-rings (0.42. These findings indicate that the oval chainring design, presented here as “Q-rings”, did not significantly influence the physiological response to an incremental exercise test as compared to a conventional chainring.

  5. Mechanisms of Aerobic Performance Impairment With Heat Stress and Dehydration

    Science.gov (United States)

    2010-08-01

    uptake ( VO2max ), which leads to higher relative exercise intensity and an exponential decline in aerobic performance at any given exercise workload...reductions, which combine to accentuate cardiovascular strain and reduce VO2max . Importantly, the negative performance consequences of dehydration...environmental heat stress on aerobic exercise “performance” has been evaluated using time to exhaustion (TTE) tests (incremental or constant work rate) and

  6. CONCURRENT TRAINING IN PREPUBESCENT CHILDREN: THE EFFECTS OF 8 WEEKS OF STRENGTH AND AEROBIC TRAINING ON EXPLOSIVE STRENGTH AND V_O2MAX

    OpenAIRE

    Alves, Ana; Marta, Carlos; Neiva, Henrique; Izquierdo, Mikel; Marques, Mário

    2016-01-01

    Concurrent training in prepubescent children: the effects of 8 weeks of strength and aerobic training on explosive strength and V_ O2max. J Strength Cond Res 30(7): 2019–2032, 2016— The purpose of this study was to compare the effects of 8-week training periods of strength training alone (GS), combined strength and aerobic training in the same session (GCOM1), or in 2 different sessions (GCOM2) on explosive strength and maximal oxygen uptake (V_ O2max) in prepubescent children. Of note, 168 h...

  7. Influência do estado nutricional e do VO2max nos níveis de adiponectina em homens acima de 35 anos

    OpenAIRE

    Martinez,Eduardo Camillo; Fortes,Macos de Sá Rego; Anjos,Luiz Antônio dos

    2011-01-01

    FUNDAMENTO: A adiponectina é considerada importante fator na patogênese das doenças cardiovasculares e metabólicas, por suas propriedades antiaterogênicas e antiinflamatórias. Poucos estudos, entretanto, sugerem a existência de relação direta entre os níveis de adiponectina e os níveis de condicionamento cardiorrespiratório e atividade física. OBJETIVO: Verificar a influência do estado nutricional e do condicionamento cardiorrespiratório nos níveis plasmáticos de adiponectina em homens adulto...

  8. La valoración del VO2 max. y su relación con el riesgo cardiovascular como medio de enseñanza-aprendizaje

    OpenAIRE

    Corral Pernía, Juan Antonio; Castillo Andrés, Óscar del

    2010-01-01

    En la actualidad educativa consideramos que es fundamental la relación de la teoría con la práctica, de ahí que a través de este estudio hayamos perseguido que el alumno realice una valoración de la condición física centrándonos en el test de Course Navette para obtener la potencia aeróbica máxima y relacionar dichos resultados con la actividad física y la salud. De esta manera, presentamos los resultados de dicho Test obtenidos por 57 sujetos (n1= 43 hombres; n2= 14 mujeres), ...

  9. Cold-induced vasodilatation of finger and maximal oxygen consumption of young female athletes born in Hokkaido

    Science.gov (United States)

    Moriya, Kiyoshi; Nakagawa, Koya

    1990-03-01

    To determine whether there is a direct correlation between endurance capacity and cold tolerance, maximal oxygen consumption (VO2max), and cold-induced vasodilatation (CIVD), we measured these factors in 14 young female athletes born in Hokkaido, Japan's northernmost island. We determined the VO2max by a standard incremental test on a cycle ergometer and measured the oxygen consumption (VO2) by means of the Douglas-bag method. We determined the CIVD reaction by measuring the skin temperature of the left middle finger during immersion in cold water at 0°C for 20 min. The athletes showed significant positive correlations between VO2max, expressed as l/min, and CIVD as well as other peripheral cold tolerance indexes (resistance index against frostbite and CIVD index). The body weight VO2max (VO2max/kg body weight) failed to correlate significantly with either the CIVD or with other cold tolerance indexes. These results suggest that CIVD in females may depend on factors other than those determined in this study, in addition to the functional spread of the vascular beds in peripheral tissues, including striated muscle; it is known that the size and the vascular bed in this tissue are affected by exercise training and that this results in the elevation of VO2max and VO2max/kg body weight.

  10. Excess VO2 during ramp exercise is positively correlated to intercostal muscles deoxyhemoglobin levels above the gas exchange threshold in young trained cyclists.

    Science.gov (United States)

    Oueslati, Ferid; Girard, Olivier; Tabka, Zouhair; Ahmaidi, Said

    2016-07-01

    We assessed respiratory muscles oxygenation responses during a ramp exercise to exhaustion and further explored their relationship with the non-linear increase of VO2 (VO2 excess) observed above the gas-exchange threshold. Ten male cyclists completed a ramp exercise to exhaustion on an electromagnetically braked cycle-ergometer with a rate of increment of 30Wmin(-1) with continuous monitoring of expired gases (breath-by-breath) and oxygenation status of intercostal muscles. Maximal inspiratory and expiratory pressure measurements were taken at rest and at exhaustion. The VO2 excess represents the difference between VO2max observed and VO2max expected using linear equation between the VO2 and the intensity before gas-exchange threshold. The deoxyhemoglobin remained unchanged until 60% of maximal aerobic power (MAP) and thereafter increased significantly by 37±18% and 40±22% at 80% and 100% of MAP, respectively. Additionally, the amplitude of deoxyhemoglobin increase between 60 and 100% of MAP positively correlated with the VO2 excess (r=0.69, p<0.05). Compared to exercise start, the oxygen tissue saturation index decreased from 80% of MAP (-4.8±3.2%, p<0.05) onwards. At exhaustion, maximal inspiratory and expiratory pressures declined by 7.8±16% and 12.6±10% (both p<0.05), respectively. In summary, our results suggest a significant contribution of respiratory muscles to the VO2 excess phenomenon.

  11. Secular trends in physical fitness in Danish adolescents

    DEFF Research Database (Denmark)

    Andersen, Lars Bo; Froberg, K; Kristensen, Peter Lund

    2010-01-01

    of Denmark in 1983, 410 in 1997, and 418 in 2003, the two latter cohorts from the City of Odense. VO(2max) was estimated from maximal power output (MPO) in a cycle test with progressively increasing workload. Estimated VO(2max) for boys and girls was 52 and 41 mL/min/kg, respectively, both in 1983, 1997......, and 2003 with no difference between the three cohorts. However, body mass index (BMI) increased 10% in the upper decentile of the distribution since 1983. MPO decreased over time, but validation studies showed that this was not due to decreased VO(2max). The cohort from 1983 was tested twice by school...

  12. Power output during women's World Cup road cycle racing.

    Science.gov (United States)

    Ebert, Tammie R; Martin, David T; McDonald, Warren; Victor, James; Plummer, John; Withers, Robert T

    2005-12-01

    Little information exists on the power output demands of competitive women's road cycle racing. The purpose of our investigation was to document the power output generated by elite female road cyclists who achieved success in FLAT and HILLY World Cup races. Power output data were collected from 27 top-20 World Cup finishes (19 FLAT and 8 HILLY) achieved by 15 nationally ranked cyclists (mean +/- SD; age: 24.1+/-4.0 years; body mass: 57.9+/-3.6 kg; height: 168.7+/-5.6 cm; VO2max 63.6+/-2.4 mL kg(-1) min(-1); peak power during graded exercise test (GXT(peak power)): 310+/-25 W). The GXT determined GXT(peak power), VO2peak lactate threshold (LT) and anaerobic threshold (AT). Bicycles were fitted with SRM powermeters, which recorded power (W), cadence (rpm), distance (km) and speed (km h(-1)). Racing data were analysed to establish time in power output and metabolic threshold bands and maximal mean power (MMP) over different durations. When compared to HILLY, FLAT were raced at a similar cadence (75+/-8 vs. 75+/-4 rpm, P=0.93) but higher speed (37.6+/-2.6 vs. 33.9+/-2.7 km h(-1), P=0.008) and power output (192+/-21 vs. 169+/-17 W, P=0.04; 3.3+/-0.3 vs. 3.0+/-0.4 W kg(-1), P=0.04). During FLAT races, riders spent significantly more time above 500 W, while greater race time was spent between 100 and 300 W (LT-AT) for HILLY races, with higher MMPs for 180-300 s. Racing terrain influenced the power output profiles of our internationally competitive female road cyclists. These data are the first to define the unique power output requirements associated with placing well in both flat and hilly women's World Cup cycling events.

  13. Análise da técnica de pedalada durante o ciclismo até a exaustão Analysis of pedaling technique during cycling until exhaustion

    Directory of Open Access Journals (Sweden)

    Fernando Diefenthaeler

    2012-09-01

    Full Text Available O objetivo deste estudo foi verificar a influência da fadiga na técnica de pedalada durante teste de ciclismo máximo até a exaustão. Oito ciclistas treinados realizaram um teste incremental máximo e um teste de carga constante até a exaustão com 48 horas de intervalo. As forças resultante (FR e efetiva (FE aplicadas no pedal foram calculadas para a determinação do índice de efetividade (IE. A FE apresentou aumento entre o início e fim do teste (de 125 ± 16 para 169 ± 52 N, p=0,03, enquanto o IE e a FR não apresentaram alterações (de 0,55 ± 0,10 para 0,59 ± 0,08, p=0,14; de 230 ± 33 para 284 ± 72 N, p=0,08, respectivamente. O tornozelo apresentou aumento na amplitude de movimento (de 19º ± 4,69 para 28 ± 7,29º, pThe aim of this study was to investigate the effects of fatigue on the pedaling technique during maximal cycling test until exhaustion. Eight well-trained cyclists completed an incremental test and a constant workload cycling test until exhaustion with 48 hours of rest. The resultant (FR and effective (FE forces were calculated to obtain the index of effectiveness (IE. FE increased from the start to the end of the test (from 125 ± 16 to 169 ± 52 N, p=0.03, whereas no differences were observed for IE and FR (from 0.55 ± 0.10 to 0.59 ± 0.08, p=0.14; from 230 ± 33 to 284 ± 72 N, p=0.08, respectively. Increases in ankle joint range of motion were observed (from 19º ± 4.69 to 28 ± 7.29º, p<0.01. Results suggest that during cycling until exhaustion well-trained cyclists are able to sustain the pedaling technique, which can be an important strategy in order to sustain the power output.

  14. Determination of Aerobic Power Through a Specific Test for Taekwondo - A Predictive Equation Model.

    Science.gov (United States)

    Rocha, Fernando P S; Louro, Hugo; Matias, Ricardo; Brito, João; Costa, Aldo M

    2016-12-01

    Our aim was to verify the concurrent validity of a maximal taekwondo specific test (TST) to predict VO2max through an explanatory model. Seventeen elite male taekwondo athletes (age: 17.59 ± 4.34 years; body height: 1.72 ± 6.5 m; body mass: 61.3 ± 8.7 kg) performed two graded maximal exercise tests on different days: a 20 m multistage shuttle run test (SRT) and an incremental TST. We recorded test time, VO2max, ventilation, a heart rate and time to exhaustion. Significant differences were found between observed and estimated VO2max values [F (2, 16) = 5.77, p taekwondo TST (r = 0.74, p = 0.001). Our results suggest that an incremental specific test estimates VO2max of elite taekwondo athletes with acceptable concurrent validity.

  15. A Comparison between Alpine Skiing, Cross-Country Skiing and Indoor Cycling on Cardiorespiratory and Metabolic Response

    Directory of Open Access Journals (Sweden)

    Thomas Stöggl, Christoph Schwarzl, Edith E. Müller, Masaru Nagasaki, Julia Stöggl, Peter Scheiber, Martin Schönfelder, Josef Niebauer

    2016-03-01

    Full Text Available Since physical inactivity especially prevails during winter months, we set out to identify outdoor alternatives to indoor cycling (IC by comparing the metabolic and cardiorespiratory responses during alpine skiing (AS, cross-country skiing (XCS and IC and analyse the effects of sex, age and fitness level in this comparison. Twenty one healthy subjects performed alpine skiing (AS, cross-country skiing (XCS, and IC. Oxygen uptake (VO2, total energy expenditure (EE, heart rate (HR, lactate, blood glucose and rate of perceived exertion (RPE were determined during three 4-min stages of low, moderate and high intensity. During XCS and IC VO2max and EE were higher than during AS. At least 2½ hours of AS are necessary to reach the same EE as during one hour of XCS or IC. HR, VO2, lactate, and RPEarms were highest during XCS, whereas RPEwhole-body was similar and RPElegs lower than during AS and IC, respectively. Weight adjusted VO2 and EE were higher in men than in women while fitness level had no effect. Male, fit and young participants were able to increase their EE and VO2 values more pronounced. Both AS and XCS can be individually tailored to serve as alternatives to IC and may thus help to overcome the winter activity deficit. XCS was found to be the most effective activity for generating a high EE and VO2 while AS was the most demanding activity for the legs.

  16. The Comparative Evaluation of the Effect of the Foods with Different Glycemic Indices on Blood Glucose and Serum Free Fatty Acids in Cycling, Male Athletes

    Directory of Open Access Journals (Sweden)

    Asadi, J. (PhD

    2014-05-01

    Full Text Available Background and Objective: Carbohydrates are considered as the major source of energy in physical activity. Studies show that consumption of carbohydrate foods before exercise can balance blood glucose and free fatty acids and increase athletes’ performance. In this study , we compared the effect of three kinds of foods with different glycemic indices on blood glucose (BG and serum free fatty acids (FFA in cycling ,male athletes. Material and Methods: In this clinical trial, 21 members of national cycling team randomly allocated to three equal groups of glucose (low glycemic index ، lentil (low glycemic index and potato (high glycemic index. First, Fasting blood samples (5ml were obtained to measure BG and FFA . Then the subjects were asked to eat their foods. After 45 mins of rest, they pedaled with maximal oxygen consumption VO2max for two hours and again their blood samples were taken to compare with the levels of before interventions. Results: Glucose consumption resulted in a significant decrease in FFA level after 2 hours of pedaling (P = 0.01 but no significant change in BG level. Plasma glucose was higher after eating lentil than that of potato (P<0.05, but it was not true for FFA level of both groups. Conclusion: Based on the results, the pre-exercise use of low glycemic index (lentil compared to high glycemic index (potato can better lead to increased blood glucose during exercise. Keywords: Glycemic Index; Blood Glucose; Serum Free Fatty Acids; Cyclists

  17. Effect of female sex hormones on cardiorespiratory parameters

    Science.gov (United States)

    Godbole, Gayatri; Joshi, A. R.; Vaidya, Savita M.

    2016-01-01

    Introduction: Female sex hormones, estrogen and progesterone regulate various phases of the menstrual cycle. Hormonal changes tend to affect various parameters of physical fitness. Maximum oxygen uptake (VO2 max) is a measure of aerobic power. This study was planned to assess effect of different phases of menstrual cycle on cardiorespiratory parameters like pulse rate, respiratory rate and VO2 max. Methods: 100 female medical students in the age group of 17-22 years were studied for three consecutive menstrual cycles. Weight, resting pulse rate, respiratory rate and VO2 max were measured during premenstrual phase (20th-25th day) and postmenstrual phase (5th to 10th day). Results: It was observed that there was a significant increase in body weight, pulse rate, and respiratory rate during premenstrual phase. There was a decrease in VO2 max during the premenstrual phase. Conclusion: This study indicates that there is decreased cardio-respiratory efficiency during premenstrual phase.

  18. Cycle training modulates satellite cell and transcriptional responses to a bout of resistance exercise.

    Science.gov (United States)

    Murach, Kevin A; Walton, R Grace; Fry, Christopher S; Michaelis, Sami L; Groshong, Jason S; Finlin, Brian S; Kern, Philip A; Peterson, Charlotte A

    2016-09-01

    This investigation evaluated whether moderate-intensity cycle ergometer training affects satellite cell and molecular responses to acute maximal concentric/eccentric resistance exercise in middle-aged women. Baseline and 72 h postresistance exercise vastus lateralis biopsies were obtained from seven healthy middle-aged women (56 ± 5 years, BMI 26 ± 1, VO2max 27 ± 4) before and after 12 weeks of cycle training. Myosin heavy chain (MyHC) I- and II-associated satellite cell density and cross-sectional area was determined via immunohistochemistry. Expression of 93 genes representative of the muscle-remodeling environment was also measured via NanoString. Overall fiber size increased ~20% with cycle training (P = 0.052). MyHC I satellite cell density increased 29% in response to acute resistance exercise before endurance training and 50% with endurance training (P training, MyHC I satellite cell density decreased by 13% in response to acute resistance exercise (acute resistance × training interaction, P trained state in response to resistance exercise. Similar satellite cell and gene expression response patterns indicate coordinated regulation of the muscle environment to promote adaptation. Moderate-intensity endurance cycle training modulates the response to acute resistance exercise, potentially conditioning the muscle for more intense concentric/eccentric activity. These results suggest that cycle training is an effective endurance exercise modality for promoting growth in middle-aged women, who are susceptible to muscle mass loss with progressing age.

  19. 40 CFR 86.1509 - Exhaust gas sampling system.

    Science.gov (United States)

    2010-07-01

    ... Regulations for Otto-Cycle Heavy-Duty Engines, New Methanol-Fueled Natural Gas-Fueled, and Liquefied Petroleum... Natural Gas-Fueled, and Liquefied Petroleum Gas-Fueled Diesel-Cycle Light-Duty Trucks; Idle Test Procedures § 86.1509 Exhaust gas sampling system. (a) The exhaust gas sampling system shall transport...

  20. Índices fisiológicos associados com a "performance" aeróbia em corredores de "endurance": efeitos da duração da prova Índices fisiológicos asociados a la "performance" aerobia en competidores de "endurance": efectos de la duración de la prueba Physiological indexes associated with aerobic performance in endurance runners: effects of race duration

    Directory of Open Access Journals (Sweden)

    Benedito Sérgio Denadai

    2004-10-01

    .000m (17,9 ± 0,9 fueron significantemente diferentes. La regresión múltiple stepwise mostró que el LAn fue el único elemento de predicción de la performance de la v5.000m, explicando el 50% de la variación de esta performance. Para la v1.500m, el Tlim y la vVO2max explicaron el 88% de la variación de la performance. Con base en nuestros resultados, se puede concluir que la validez de los índices fisiológicos (VO2max, vVO2max, Tlim, EC y LAn, para la predicción de la performance aerobia de atletas de endurance depende de la distancia de la prueba (1.500 x 5.000m analizada.The aim of this study was to assess the validity of the maximal oxygen uptake (VO2max, the velocity at VO2max (vVO2max, time to exhaustion at vVO2max (Tlim, running economy (RE and anaerobic threshold (AnT to predict the aerobic performance of the endurance athletes. Fourteen well-trained long-distance runners (33.4 ± 4.4 yr.; 62.7 ± 4.3 kg; 166.1 ± 5.0 cm; VO2max = 60.4 ± 5.9 ml.kg-1.min-1 underwent the following tests: a simulated competitions in the distances of 1500 and 5000 m and; b laboratory treadmill tests to determine their VO2max, vVO2max, Tlim, EC and AnT. The velocities (km/h at vVO2max (18.7 + 0.8, LAn (17.3 + 1.1 v1500 m (19.9 + 0.8 and v5000 m (17.9 + 0.9 were significantly different. A stepwise multiple-regression analysis revealed that AnT alone was the best single predictor of v-5000 m and explained 50% of the variability in 5000 m running velocity. For v1.500 m, Tlim and vVO2max explained 88 % of the variability of the performance. We conclude that, in a group of well-trained long-distance runners, the validity of the physiological indexes (VO2max, vVO2max, Tlim, EC e LAn to predict the aerobic performance is dependent of the distance (1500 x 5000 m analyzed.

  1. Exhaust Gas Energy Recovery Technology Applications

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Robert M [ORNL; Szybist, James P [ORNL

    2014-01-01

    Exhaust waste heat recovery systems have the potential to significantly improve vehicle fuel economy for conventional and hybrid electric powertrains spanning passenger to heavy truck applications. This chapter discusses thermodynamic considerations and three classes of energy recovery technologies which are under development for vehicle applications. More specifically, this chapter describes the state-of-the-art in exhaust WHR as well as challenges and opportunities for thermodynamic power cycles, thermoelectric devices, and turbo-compounding systems.

  2. Comparison of Cooling System Designs for an Exhaust Heat Recovery System Using an Organic Rankine Cycle on a Heavy Duty Truck

    Directory of Open Access Journals (Sweden)

    Nicolas Stanzel

    2016-11-01

    Full Text Available A complex simulation model of a heavy duty truck, including an Organic Rankine Cycle (ORC based waste heat recovery system and a vehicle cooling system, was applied to determine the system fuel economy potential in a typical drive cycle. Measures to increase the system performance were investigated and a comparison between two different cooling system designs was derived. The base design, which was realized on a Mercedes-Benz Actros vehicle revealed a fuel efficiency benefit of 2.6%, while a more complicated design would generate 3.1%. Furthermore, fully transient simulation results were performed and are compared to steady state simulation results. It is shown that steady state simulation can produce comparable results if averaged road data are used as boundary conditions.

  3. No effect of menstrual cycle phase on glucose and glucoregulatory endocrine responses to prolonged exercise.

    Science.gov (United States)

    Kraemer, Robert R; Francois, Michelle; Webb, Nancy Dardis; Worley, Jennifer R; Rogers, Sharon N; Norman, Reid L; Shah, Urvi; Castracane, V Daniel; Daniel Castracane, V

    2013-09-01

    Prolonged exercise requires increased utilization of blood glucose and adjustment of glucoregulatory hormones. Estrogen can reduce hepatic gluconeogenesis which could affect insulin concentrations. Amylin is co-secreted with insulin and controls influx of glucose into the blood. To determine the effect of menstrual cycle stage on glucose, leptin, and pancreatic hormone responses to prolonged (90 min) exercise. Five healthy, eumenorrheic women (24.6 ± 5.1 years; 67.4 ± 1 kg) were monitored for 3 months to determine menstrual cycle length. Subjects completed a preliminary session to determine exercise workloads and, in a fasted condition, completed two randomized 90-min treadmill exercise trials at 60 % VO2max during the early follicular (EFX) and mid-luteal phase (MLX) of their menstrual cycle. Blood samples were analyzed for glucose, insulin, C-peptide, amylin, glucagon, leptin, and cortisol concentrations at rest (-30 and 0 min), during exercise (18, 36, 54, 72, and 90 min) and after 20 min of recovery. No changes in amylin, leptin, or cortisol occurred for EFX and MLX trials. A significant (p effect occurred for glucose, insulin, and glucagon with reduced insulin across the exercise trial and increases in glucose and glucagon later in the trial, but there were no differences between the EFX and MLX trials. Menstrual cycle stage does not affect glucose, insulin, C-peptide, amylin, glucagon, cortisol, and leptin responses to prolonged exercise; however, the exercise reduces insulin and increases glucose and glucagon concentrations. This is the first study to determine acute effects of exercise on amylin and other glucoregulatory hormone responses in women.

  4. RELATIONSHIPS BETWEEN MUSCLE FATIGUE CHARACTERISTICS AND MARKERS OF ENDURANCE PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Martyn G. Morris

    2008-12-01

    Full Text Available The aim of this study was to examine the relationship of a range of in-vivo whole muscle characteristics to determinants of endurance performance. Eleven healthy males completed a cycle ergometer step test to exhaustion for the determination of the lactate threshold, gross mechanical efficiency, peak power and VO2max. On two separate occasions, contractile and fatigue characteristics of the quadriceps femoris were collected using a specially designed isometric strength-testing chair. Muscle fatigue was then assessed by stimulating the muscle for 3 minutes. Force, rate of force development and rates of relaxation were calculated at the beginning and end of the 3 minute protocol and examined for reliability and in relation to lactate threshold, VO2max, gross mechanical efficiency and peak power. Muscle characteristics, rate of force development and relaxation rate were demonstrated to be reliable measures. Force drop off over the 3 minutes (fatigue index was related to lactate threshold (r = -0.72 p < 0.01 but not to VO2max. The rate of force development related to the peak power at the end of the cycle ergometer test (r = -0.75 p < 0.01. Rates of relaxation did not relate to any of the performance markers. We found in-vivo whole muscle characteristics, such as the fatigue index and rate of force development, relate to specific markers of peripheral, but not to central, fitness components. Our investigation suggests that muscle characteristics assessed in this way is reliable and could be feasibly utilised to further our understanding of the peripheral factors underpinning performance

  5. Effects of 4:1 carbohydrate/protein solution versus a carbohydrate-alone solution on IL-6, TNF-α, and cortisol during prolonged cycling in hot environmental conditions.

    Science.gov (United States)

    Cosio-Lima, Ludmila M; Desai, Bhargav; Stelzer, John W; Schuler, Petra B

    2012-01-01

    Intense or prolonged exercise and/or heat stress might affect the immune system creating a response similar to trauma or inflammation, resulting in an increase in the susceptibility to viral infections. For example, during prolonged exercise, inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-6, and the stress hormone cortisol are produced and released. Although there have been several studies examining the effects of nutritional supplementation on cytokine release in elite athletes, few studies have investigated the effects of different energy drinks during exercise in adverse environmental conditions. Therefore, the purpose of this study was to compare plasma levels of inflammatory cytokines TNF-α and IL-6, and the stress hormone cortisol, during prolonged cycling under hot environmental conditions while ingesting fluid that contains a ratio of 4:1 carbohydrates and protein (4:1 CHO/PRO) versus a carbohydrate-only drink (CHO). Six male cyclists (aged 27 ± 8 years; weight 75.5 ± 3.4 kg; VO2max = 66 ± 2.7 mL/kg/min, mean ± standard error) rode on a stationary ergometer on two separate sessions for 2.5 hours at 75% VO2max in an environmental chamber set at 35°C and 60% relative humidity. During the first session the cyclists were given 4 mL/kg body weight of a 6% carbohydrate solution every 15 minutes. During the second session they were given 4 mL/kg body weight of a 4:1 carbohydrate/protein drink every 15 minutes. Subjects were not aware of which drink they were given in each trial. Blood samples were taken pre-, immediately post-, and 12 hours post-exercise. SPSS (IBM Corp, Armonk, NY) was utilized to analyze data through repeated measures analysis of variance. No significant main effect was observed between treatments in either cortisol (P = 0.97), IL-6 (P = 0.64), or TNF-α (P = 0.37) responses. Total cortisol concentrations were significantly elevated (P effects on inflammatory cytokines to drinking a CHO-alone solution.

  6. Reduction in muscle glycogen and protein utilization with glucose feeding during exercise.

    NARCIS (Netherlands)

    Hamont, D. van; Harvey, C.R.; Massicotte, D.; Frew, R.; Peronnet, F.; Rehrer, N.J.

    2005-01-01

    Effects of feeding glucose on substrate metabolism during cycling were studied. Trained (60.0 +/- 1.9 mL x kg(-1) x min(-1)) males (N = 5) completed two 75 min, 80% VO(2max) trials: 125 g 13(C)-glucose CHO); 13(C)-glucose tracer, 10 g (C). During warm-up (30 min 30% VO2max) 2 . 2 g 13(C)-glucose was

  7. Combined speed endurance and endurance exercise amplify the exercise-induced PGC-1α and PDK4 mRNA response in trained human muscle

    DEFF Research Database (Denmark)

    Skovgaard, Casper; Brandt, Nina; Pilegaard, Henriette

    2016-01-01

    trained male subjects (maximum oxygen uptake (VO2-max): 57.2 ± 3.7 (mean ± SD) mL·min(-1)·kg(-1)) performed S (6 × 30 sec all-out), E (60 min ~60% VO2-max), and S + E on a cycle ergometer on separate occasions. Muscle biopsies were obtained at rest and 1, 2, and 3 h after the speed endurance exercise (S...

  8. Reduction in muscle glycogen and protein utilization with glucose feeding during exercise.

    NARCIS (Netherlands)

    Hamont, D. van; Harvey, C.R.; Massicotte, D.; Frew, R.; Peronnet, F.; Rehrer, N.J.

    2005-01-01

    Effects of feeding glucose on substrate metabolism during cycling were studied. Trained (60.0 +/- 1.9 mL x kg(-1) x min(-1)) males (N = 5) completed two 75 min, 80% VO(2max) trials: 125 g 13(C)-glucose CHO); 13(C)-glucose tracer, 10 g (C). During warm-up (30 min 30% VO2max) 2 . 2 g 13(C)-glucose was

  9. A valid and reproducible protocol for testing maximal oxygen uptake in rabbits.

    Science.gov (United States)

    Gaustad, Svein Erik; Rolim, Natale; Wisløff, Ulrik

    2010-02-01

    Physiological studies of long-term cardiovascular adaptation to exercise require adequate testing procedures to quantify the outcome. Such test procedures are well established in rats and mice. However, the use of these species may have limitations, and to study several physiological parameters mimicking 'the human adaptation' larger animal models may be preferable. Here, we established a valid and reproducible exercise test protocol for measuring maximal oxygen uptake (VO2max) in rabbits. The VO2max protocol was studied in six adult female New Zealand White rabbits running on a treadmill at inclinations ranging from 0 to 20 degrees. VO2max was reached at all inclinations indicating that the rabbits reach exhaustion independent of inclination. Average VO2max for test and retest were 35.1+/-4.2 and 35.8+/-4.0 ml/kg per min, respectively. Oxygen uptake and heart rate increased linearly with increased running speed. Average running speed at VO2max was 0.51+/-0.09 m/s, and there was an increase oxygen pulse up to the intensity corresponding to VO2max, where it leveled off and declined. This study shows that rabbit is a suitable species for studying responses to training and could be of great importance for showing novel cellular cardiac adaptations to training.

  10. Hyperventilation and exhaustion syndrome

    OpenAIRE

    Ristiniemi, Heli; Perski, Aleksander; Lyskov, Eugene; Emtner, Margareta

    2014-01-01

    Chronic stress is among the most common diagnoses in Sweden, most commonly in the form of exhaustion syndrome (ICD-10 classification - F43.8). The majority of patients with this syndrome also have disturbed breathing (hyperventilation). The aim of this study was to investigate the association between hyperventilation and exhaustion syndrome. Thirty patients with exhaustion syndrome and 14 healthy subjects were evaluated with the Nijmegen Symptom Questionnaire (NQ). The participants completed ...

  11. Monitoring Perceived Stress and Recovery in Relation to Cycling Performance in Female Athletes.

    Science.gov (United States)

    Otter, R T A; Brink, M S; van der Does, H T D; Lemmink, K A P M

    2016-01-01

    The purpose was to investigate perceived stress and recovery related to cycling performance of female athletes over one full year. 20 female athletes (age, 27±8 years; ˙VO2max, 50.3±4.6 mL·kg(-1)·min(-1)) were measured 8 times in one year to determine perceived stress and recovery (RESTQ-Sport) in relation to cycling performance (Lamberts and Lambert Submaximal Cycle Test (LSCT)). All 19 RESTQ-Sport scales were calculated and scores of the 4 main categories were determined (i. e., general stress, general recovery, sport-specific stress and sport-specific recovery). A balance score of total stress and recovery was calculated by recovery-stress. Power at the second stage (P80), third stage (P90) and heart rate recovery (HRR60 s) of the LSCT were determined as performance parameters. 110 RESTQ-Sports and LSCTs were analysed using a multilevel approach (random intercepts model). Higher self-efficacy was related to improvement of all performance parameters. Higher total recovery stress, and lower emotional stress were related to improvement of P90 and HRR60 s. Higher sport-specific recovery was related to P80, higher general stress, fatigue and physical complaints were related to decreased P90 and higher social stress and injury were related to decreased HRR60 s. Improved perceived recovery and stress contributed to an improved performance. Relevant information could be provided by monitoring changes in perceived stress and recovery of female athletes.

  12. A pilot study: bovine colostrum supplementation and hormonal and autonomic responses to competitive cycling.

    Science.gov (United States)

    Shing, C M; Peake, J M; Suzuki, K; Jenkins, D G; Coombes, J S

    2013-10-01

    The aim of this pilot investigation was to examine the influence of bovine colostrum protein concentrate (CPC) supplementation on salivary hormones, salivary IgA and heart rate variability over consecutive days of competitive cycling. Ten highly-trained male road cyclists (mean±SEM; age=22.2±4.7 yr; mass=70.5±4.5 kg; VO2max=72.9±3.8 mL.kg-1.min-1) were randomly assigned to a control (N.=6, 10g whey protein concentrate/day) or bovine CPC group (N.=4, 10 g bovine CPC/day). Cyclists provided a baseline saliva sample before commencing eight weeks of supplementation, and competing in a five day cycle race. Cyclists provided saliva samples and measured heart rate variability (HRV) each day of the race. Saliva samples were analysed for cortisol, testosterone and IgA concentrations. Bovine CPC supplementation was associated with increased morning cortisol concentration on the first day of racing when compared to the control group (P=0.004) and significantly prevented a decrease in testosterone concentration over the race period (P≤0.05). Across the race period parasympathetic indices of HRV were elevated in the bovine CPC group and reduced in the control group (P≤0.05), while there were no significant differences in salivary IgA between groups. Bovine CPC supplementation maintained salivary testosterone concentration and modulated autonomic activity over consecutive days of competitive cycling. This pilot study provides justification to explore the effects of bovine CPC on recovery in endurance athletes further.

  13. The effect of a caffeinated energy drink on various psychological measures during submaximal cycling.

    Science.gov (United States)

    Duncan, Michael J; Hankey, Joanne

    2013-05-27

    Caffeine containing energy drinks is commonly consumed in the belief that it will enhance the quality of an exercise session and enhance mood. However, studies examining their efficacy are sparse. The aim of this study was to examine the effect of a caffeinated energy drink on leg pain perception, perceived exertion, mood state and readiness to invest effort pre, during and post 60 min cycling exercise. Fourteen active individuals (7 males, 7 females, mean age ± S.D.=23.5 ± 3.5 years), completed two 60 min cycling trials at an intensity of 60% VO2 max preceded by ingestion of solutions containing either a caffeinated energy drink or placebo using a double-blind, deceptive, crossover design. During exercise, RPE (6-20 scale), leg pain (0-10 scale), heart rate (HR) and blood lactate (Bla) were recorded. Participants also completed measures of mood state and readiness to invest physical effort (RTIPE) pre- and post-exercise. Repeated measures analysis of variance was used to assess differences in all variables and across time and treatments, with gender used as a between subjects variable. Results indicate that HR was significantly higher (P=.002) from 30 to 60 min and RPE (P=.0001) and pain perception (P=.0001) were significantly lower from 20 to 60 min in the energy drink condition compared to placebo. Bla was significantly higher (P=.021) in the last 15 min of the energy drink trial and RTIPE (P=.001) increased significantly more from pre-ingestion to pre-exercise post-ingestion in the energy drink condition compared to placebo. No gender differences were evident (P>.05). The data revealed positive effects of energy drink ingestion on perception of exertion, leg muscle pain perception and readiness to invest effort during submaximal cycling in active adults.

  14. The effects of Red Bull energy drink compared with caffeine on cycling time-trial performance.

    Science.gov (United States)

    Quinlivan, Alannah; Irwin, Christopher; Grant, Gary D; Anoopkumar-Dukie, Sheilandra; Skinner, Tina; Leveritt, Michael; Desbrow, Ben

    2015-10-01

    This study investigated the ergogenic effects of a commercial energy drink (Red Bull) or an equivalent dose of anhydrous caffeine in comparison with a noncaffeinated control beverage on cycling performance. Eleven trained male cyclists (31.7 ± 5.9 y 82.3 ± 6.1 kg, VO2max = 60.3 ± 7.8 mL · kg-1 · min-1) participated in a double-blind, placebo-controlled, crossover-design study involving 3 experimental conditions. Participants were randomly administered Red Bull (9.4 mL/kg body mass [BM] containing 3 mg/kg BM caffeine), anhydrous caffeine (3 mg/kg BM given in capsule form), or a placebo 90 min before commencing a time trial equivalent to 1 h cycling at 75% peak power output. Carbohydrate and fluid volumes were matched across all trials. Performance improved by 109 ± 153 s (2.8%, P = .039) after Red Bull compared with placebo and by 120 ± 172 s (3.1%, P = .043) after caffeine compared with placebo. No significant difference (P > .05) in performance time was detected between Red Bull and caffeine treatments. There was no significant difference (P > .05) in mean heart rate or rating of perceived exertion among the 3 treatments. This study demonstrated that a moderate dose of caffeine consumed as either Red Bull or in anhydrous form enhanced cycling time-trial performance. The ergogenic benefits of Red Bull energy drink are therefore most likely due to the effects of caffeine, with the other ingredients not likely to offer additional benefit.

  15. Effects of knee frontal plane position on pedal forces during cycling: A preliminary study

    Directory of Open Access Journals (Sweden)

    Fernando Diefenthaeler

    2009-04-01

    Full Text Available The purpose of this study was to compare the force applied to the pedal when cycling with the knees almost touching the bicycle frame (adduction position compared to the position usually adopted by cyclists (reference position and a position of the knees away from the bicycle frame (abduction position. Six cyclists were evaluated. Maximal oxygen uptake (VO2MAX was defined, and then the three different knee positions on the frontal plane were assessed. Three minutes of cycling in the reference position, adduction position and abduction position were conducted, using oxygen uptake (VO2 at which the cyclists had achieved the second ventilatory threshold. An instrumented two-dimensional pedal was used to measure the forces applied to the right pedal. The average VO2 and power output did not differ between the adduction (50.4±6.9 ml.kg-1.min-1 and 263±29 W, abduction (50.8±5.9 ml.kg-1.min-1 and 250±46 W and reference position (50.4±5.9 ml.kg-1.min-1 and 246±47 W. Pedaling cadence increased significantly during adduction (94±8 rpm and abduction (95±5 rpm compared to the reference position (89±8 rpm. The force results indicated no differences in the effective force or effectiveness index between the reference, adduction and abduction positions. Resultant force increased during adduction (284.5±44.5 N compared to the reference position (246.9±39.2 N. The results indicate that the cyclists were able to generate higher resultant force during cycling with the knees close to the bicycle frame, but were unable to effectively transmit this force to the movement.

  16. Local Exhaust Ventilation

    DEFF Research Database (Denmark)

    Madsen, Ulla; Breum, N. O.; Nielsen, Peter V.

    Capture efficiency of a local exhaust system, e.g. a kitchen hood, should include only contaminants being direct captured. In this study basic concepts of local exhaust capture efficiency are given, based on the idea of a control box. A validated numerical model is used for estimation of the capt......Capture efficiency of a local exhaust system, e.g. a kitchen hood, should include only contaminants being direct captured. In this study basic concepts of local exhaust capture efficiency are given, based on the idea of a control box. A validated numerical model is used for estimation...

  17. Exhaustion from prolonged gambling

    Directory of Open Access Journals (Sweden)

    Fatimah Lateef

    2013-01-01

    Full Text Available Complaints of fatigue and physical exhaustion are frequently seen in the acute medical setting, especially amongst athletes, army recruits and persons involved in strenuous and exertional physical activities. Stress-induced exhaustion, on the other hand, is less often seen, but can present with very similar symptoms to physical exhaustion. Recently, three patients were seen at the Department of Emergency Medicine, presenting with exhaustion from prolonged involvement in gambling activities. The cases serve to highlight some of the physical consequences of prolonged gambling.

  18. Exhaustion from prolonged gambling

    Institute of Scientific and Technical Information of China (English)

    Fatimah Lateef

    2013-01-01

    Complaints of fatigue and physical exhaustion are frequently seen in the acute medical setting, especially amongst athletes, army recruits and persons involved in strenuous and exertional physical activities.Stress-induced exhaustion, on the other hand, is less often seen, but can present with very similar symptoms to physical exhaustion.Recently, three patients were seen at theDepartment ofEmergencyMedicine, presenting with exhaustion from prolonged involvement in gambling activities.The cases serve to highlight some of the physical consequences of prolonged gambling.

  19. Aerobic fitness after JDM--a long-term follow-up study

    DEFF Research Database (Denmark)

    Mathiesen, Pernille R; Orngreen, Mette C; Vissing, John

    2013-01-01

    with JDM. We hypothesized that fitness (VO(2max)) is reduced compared with healthy controls in the years after active JDM. Methods. A maximal exercise test was performed using a cycle ergometer. Results were compared with those of sex- and age-matched healthy controls. Results. A total of 36 patients......Objectives. It has previously been shown that patients with active JDM have decreased aerobic fitness; however, it is not known whether these patients regain their physical fitness after recovery. The objective of this study was to investigate the long-term outcome of aerobic fitness in patients...... with JDM in remission were included, 2-36 years after disease onset. Twelve patients (33%) had normal VO(2max) and 24 patients (67%) had decreased VO(2max). Mean VO(2max) was higher in the healthy controls vs patients (P

  20. Importance of proper scaling of aerobic power when relating to cardiometabolic risk factors in children

    DEFF Research Database (Denmark)

    McMurray, Robert; Hosick ‎, Peter; Bugge, Anna

    2011-01-01

    BACKGROUND: The relationship between cardiometabolic risk factors (CMRF) and aerobic power (VO(2max)) scaled as mL O(2) per kilogram body mass is controversial because mass includes both fat and fat-free mass, and fat mass is independently associated with the CMRF. AIM: To examine common units used...... to scale VO(2max) and their relationships to mean blood pressure (MBP), total cholesterol (TC), HDL cholesterol, triglycerides (TG), insulin resistance (HOMA-IR) and cumulative risk score (z-score). SUBJECTS: 1784, 8-18 year-old youths, 938 girls and 886 boys. METHODS: Fasting blood samples were obtained....... VO(2max) was estimated in mL/min from cycle ergometry and scaled to body mass (kg), fat free mass (kg(FFM)), body surface area (m(2)), height (cm) and allometric (mL/kg(0.67)/min). RESULTS: Unadjusted correlations between CMRF and many of the scaled VO(2max) units were significant (p

  1. Guidelines to Classify Female Subject Groups in Sport-Science Research.

    Science.gov (United States)

    Decroix, Lieselot; De Pauw, Kevin; Foster, Carl; Meeusen, Romain

    2016-03-01

    To review current cycling-related sport-science literature to formulate guidelines to classify female subject groups and to compare this classification system for female subject groups with the classification system for male subject groups. A database of 82 papers that described female subject groups containing information on preexperimental maximal cycle-protocol designs, terminology, biometrical and physiological parameters, and cycling experience was analyzed. Subject groups were divided into performance levels (PLs), according to the nomenclature. Body mass, body-mass index, maximal oxygen consumption (VO2max), peak power output (PPO), and training status were compared between PLs and between female and male PLs. Five female PLs were defined, representing untrained, active, trained, well-trained, and professional female subjects. VO2max and PPO significantly increased with PL, except for PL3 and PL4 (P VO2max and PPO between male and female subject groups. Relative VO2max is the most cited parameter for female subject groups and is proposed as the principal parameter to classify the groups. This systematic review shows the large variety in the description of female subject groups in the existing literature. The authors propose a standardized preexperimental testing protocol and guidelines to classify female subject groups into 5 PLs based on relative VO2max, relative PPO, training status, absolute VO2max, and absolute PPO.

  2. Unemployment Benefit Exhaustion

    DEFF Research Database (Denmark)

    Filges, Trine; Pico Geerdsen, Lars; Knudsen, Anne-Sofie Due

    2015-01-01

    This systematic review studied the impact of exhaustion of unemployment benefits on the exit rate out of unemployment and into employment prior to benefit exhaustion or shortly thereafter. Method: We followed Campbell Collaboration guidelines to prepare this review, and ultimately located 12...

  3. Estimated Aerobic Capacity Changes in Adolescents with Obesity Following High Intensity Interval Exercise

    Directory of Open Access Journals (Sweden)

    Brooke E. Starkoff

    2014-07-01

    Full Text Available Vigorous aerobic exercise may improve aerobic capacity (VO2max and cardiometabolic profiles in adolescents with obesity, independent of changes to weight. Our aim was to assess changes in estimated VO2max in obese adolescents following a 6-week exercise program of varying intensities. Adolescents with obesity were recruited from an American mid-west children’s hospital and randomized into moderate exercise (MOD or high intensity interval exercise (HIIE groups for a 6-week exercise intervention, consisting of cycle ergometry for 40 minutes, 3 days per week. Heart rate was measured every two minutes during each exercise session.  Estimated VO2max measured via Åstrand cycle test, body composition, and physical activity (PA enjoyment evaluated via questionnaire were assessed pre/post-intervention. Twenty-seven adolescents (age 14.7±1.5; 17 female, 10 male completed the intervention. Estimated VO2max increased only in the HIIE group (20.0±5.7 to 22.7±6.5 ml/kg/min, p=0.015. The HIIE group also demonstrated increased PA enjoyment, which was correlated with average heart rate achieved during the intervention (r=0.55; p=0.043. Six weeks of HIIE elicited improvements to estimated VO2max in adolescents with obesity. Furthermore, those exercising at higher heart rates demonstrated greater PA enjoyment, implicating enjoyment as an important determinant of VO2max, specifically following higher intensity activities.

  4. The effect of dietary restriction and menstrual cycle on excess post-exercise oxygen consumption (EPOC) in young women.

    Science.gov (United States)

    Fukuba, Y; Yano, Y; Murakami, H; Kan, A; Miura, A

    2000-03-01

    The purpose of this study was to evaluate the effect of acute dietary restriction on excess post-exercise oxygen consumption (EPOC) in young women at two different phases of the menstrual cycle. Five young sedentary women (age 21-22 years) participated in this study. Each subject visited the laboratory eight times for measurement of EPOC. They performed cycle ergometer exercise for 60 min at a work rate corresponding to approximately 70% of VO2max under each four different conditions (i.e. standard diet/follicular phase (SF), standard diet/luteal phase (SL), restricted diet/follicular phase (RF) and restricted diet/luteal phase (RL)). The exercise was performed in the morning and VO2 was measured for the last 15 min of each hour for 7 h after the exercise. As a control, VO2 was also measured with an identical time schedule under the same four conditions but without exercise. EPOC was calculated as the difference of the VO2-time integral for 7 h between the exercise and control trial days in each of the four conditions (i.e. SL, SF, RL and RF). The diet was precisely controlled during 2 days (i.e. the test day and the day preceding it). The standard diet was 1600 kcal day-1 and the restricted diet was half of the standard diet. A two-way (dietary and menstrual cycle factors) ANOVA indicated that EPOC was significantly affected only by the dietary factor. The dietary restriction decreased EPOC compared to the standard dietary condition (SF 8.6 +/- 2.1, RF 5.3 +/- 1.6, SL 8.9 +/- 4.8, RL 4.0 +/- 1.2 l). These data indicate that for young sedentary women, EPOC is significantly lowered by prior acute dietary restriction but is not influenced by different phases of the menstrual cycle.

  5. Cordyceps militaris Improves Tolerance to High-Intensity Exercise After Acute and Chronic Supplementation.

    Science.gov (United States)

    Hirsch, Katie R; Smith-Ryan, Abbie E; Roelofs, Erica J; Trexler, Eric T; Mock, Meredith G

    2016-07-13

    To determine the effects of a mushroom blend containing Cordyceps militaris on high-intensity exercise after 1 and 3 weeks of supplementation. Twenty-eight individuals (Mean ± standard deviation [SD]; Age = 22.7 ± 4.1 yrs; Height = 175.4 ± 8.7 cm; Weight = 71.6 ± 12.0 kg) participated in this randomized, repeated measures, double-blind, placebo-controlled design. Maximal oxygen consumption (VO2max), time to exhaustion (TTE), and ventilatory threshold (VT) were measured during a maximal graded exercise test on a cycle ergometer. Relative peak power output (RPP), average power output (AvgP), and percent drop (%drop) were recorded during a 3 minute maximal cycle test with resistance at 4.5% body weight. Subjects consumed 4 g·d(-1) mushroom blend (MR) or maltodextrin (PL) for 1 week. Ten volunteers supplemented for an additional 2 weeks. Exercise tests were separated by at least 48 hours and repeated following supplementation periods. One week of supplementation elicited no significant time × treatment interaction for VO2max (p = 0.364), VT (p = 0.514), TTE (p = 0.540), RPP (p = 0.134), AvgP (p = 0.398), or %drop (p = 0.823). After 3 weeks, VO2max significantly improved (p = 0.042) in MR (+4.8 ml·kg(-1)·min(-1)), but not PL (+0.9 ml·kg(-1)·min(-1)). Analysis of 95% confidence intervals revealed significant improvements in TTE after 1- (+28.1 s) and 3 weeks (+69.8 s) in MR, but not PL, with additional improvements in VO2max (+4.8 ml·kg(-1)·min(-1)) and VT (+0.7 l·min(-1)) after 3 weeks. Acute supplementation with a Cordyceps militaris containing mushroom blend may improve tolerance to high-intensity exercise; greater benefits may be elicited with consistent chronic supplementation.

  6. The relation of fat-free mass to maximum exercise performance in patients with chronic obstructive pulmonary disease.

    Science.gov (United States)

    Kobayashi, A; Yoneda, T; Yoshikawa, M; Ikuno, M; Takenaka, H; Fukuoka, A; Narita, N; Nezu, K

    2000-01-01

    To assess the factors determining maximum exercise performance in patients with chronic obstructive pulmonary disease (COPD), we examined nutritional status with special reference to body composition and pulmonary function in 50 stable COPD patients. Nutritional status was evaluated by body weight and body composition, including fat mass (FM) and fat-free mass (FFM) assessed by bioelectrical impedance analysis (BIA). Exercise performance was evaluated by maximum oxygen uptake (Vo(2max)) on a cycle ergometer. A total of 50 patients (FEV(1) = 0.98 L) was divided randomly into either a study group (group A, n = 25) or validation group (group B, n = 25). Stepwise regression analysis was performed in group A to determine the best predictors of Vo(2max) from measurements of pulmonary function and nutritional status. Stepwise regression analysis revealed that Vo(2max) was predicted best by the following equation in group A: Vo(2max) (mL/min) = 10.223 x FFM (kg) + 4.188 x MVV (L/min) + 9.952 x DL(co) (mL/min/mmHg) - 127.9 (r = 0.84, p equation was then cross-validated in group B: Measured Vo(2max) (mL/min) = 1.554 x Predicted Vo(2max) (mL/min) - 324.0 (r = 0.87, p < 0.001). We conclude that FFM is an important factor in determining maximum exercise performance, along with pulmonary function parameters, in patients with COPD.

  7. Multispectral imaging of aircraft exhaust

    Science.gov (United States)

    Berkson, Emily E.; Messinger, David W.

    2016-05-01

    Aircraft pollutants emitted during the landing-takeoff (LTO) cycle have significant effects on the local air quality surrounding airports. There are currently no inexpensive, portable, and unobtrusive sensors to quantify the amount of pollutants emitted from aircraft engines throughout the LTO cycle or to monitor the spatial-temporal extent of the exhaust plume. We seek to thoroughly characterize the unburned hydrocarbon (UHC) emissions from jet engine plumes and to design a portable imaging system to remotely quantify the emitted UHCs and temporally track the distribution of the plume. This paper shows results from the radiometric modeling of a jet engine exhaust plume and describes a prototype long-wave infrared imaging system capable of meeting the above requirements. The plume was modeled with vegetation and sky backgrounds, and filters were selected to maximize the detectivity of the plume. Initial calculations yield a look-up chart, which relates the minimum amount of emitted UHCs required to detect the presence of a plume to the noise-equivalent radiance of a system. Future work will aim to deploy the prototype imaging system at the Greater Rochester International Airport to assess the applicability of the system on a national scale. This project will help monitor the local pollution surrounding airports and allow better-informed decision-making regarding emission caps and pollution bylaws.

  8. Unemployment Benefit Exhaustion

    DEFF Research Database (Denmark)

    Filges, Trine; Pico Geerdsen, Lars; Knudsen, Anne-Sofie Due

    2015-01-01

    studies for final analysis and interpretation. Twelve studies could be included in the data synthesis. Results: We found clear evidence that the prospect of exhaustion of benefits results in a significantly increased incentive for finding work. Discussion: The theoretical suggestion that the prospect......This systematic review studied the impact of exhaustion of unemployment benefits on the exit rate out of unemployment and into employment prior to benefit exhaustion or shortly thereafter. Method: We followed Campbell Collaboration guidelines to prepare this review, and ultimately located 12...... of exhaustion of benefits results in an increased incentive for finding work has been confirmed empirically by measures from seven different European countries, the United States, and Canada. The results are robust in the sense that sensitivity analyses evidenced no appreciable changes in the results. We found...

  9. Differences in oxygen uptake but equivalent energy expenditure between a brief bout of cycling and running

    Directory of Open Access Journals (Sweden)

    Bunker Michael P

    2006-01-01

    Full Text Available Abstract Background We examined aerobic and anaerobic exercise energy expenditure and excess post-exercise oxygen consumption (EPOC between a 250 Watt, 1-minute bout of cycling and uphill treadmill running. Methods Fourteen active to well-trained subjects volunteered for the investigation (VO2 max: 57.0 ± 12.9 ml·kg·min-1 cycle; 59.3 ± 13.7 ml·kg·min-1 run; p = 0.44. Anaerobic energy expenditure was estimated from △blood lactate. Statistical analysis was completed using a paired t-test (mean ± SD. Results Perceived exertion did not differ between exercise bouts (14.0 ± 2.3 cycle; 13.2 ± 2.1 run; p = 0.29. Exercise oxygen uptake was significantly greater for running (41.4 ± 6.9 kJ compared to cycling (31.7 ± 7.7 kJ (p = 0.0001. EPOC was not different between cycling and running (p = 0.21 so that exercise oxygen uptake + EPOC was greater for running (103.0 ± 13.5 kJ as compared to cycling (85.4 ± 20.2 kJ; p = 0.008. Anaerobic energy expenditure was significantly greater for cycling (32.7 ± 8.9 kJ versus running (22.5 ± 11.1 kJ (p = 0.009. Aerobic + anaerobic exercise energy expenditure (cycle 64.3 ± 12.2 kJ; run 63.9 ± 10.1 kJ (p = 0.90 and total energy expenditure (including EPOC; cycle 118.0 ± 21.8 kJ; run 125.4 ± 19.1 kJ; p = 0.36 were similar for cycling and running. Conclusion Oxygen-only measures reveal discrepancy in energy expenditure between cycling and uphill running. Measurements of exercise oxygen uptake, △blood lactate and a modified EPOC promote the hypothesis of a similarity in exercise and total energy expenditure between 1-minute work-equivalent bouts of cycling and uphill running.

  10. Endurance training of respiratory muscles improves cycling performance in fit young cyclists

    Directory of Open Access Journals (Sweden)

    Holm Paige

    2004-05-01

    Full Text Available Abstract Background Whether or not isolated endurance training of the respiratory muscles improves whole-body endurance exercise performance is controversial, with some studies reporting enhancements of 50 % or more, and others reporting no change. Twenty fit (VO2 max 56.0 ml/kg/min, experienced cyclists were randomly assigned to three groups. The experimental group (n = 10 trained their respiratory muscles via 20, 45 min sessions of hyperpnea. The placebo group (n = 4 underwent "sham" training (20, 5 min sessions, and the control group (n = 6 did no training. Results After training, the experimental group increased their respiratory muscle endurance capacity by 12 %. Performance on a bicycle time trial test designed to last about 40 min improved by 4.7 % (9 of 10 subjects showed improvement. There were no test-re-test improvements in either respiratory muscle or bicycle exercise endurance performance in the placebo group, nor in the control group. After training, the experimental group had significantly higher ventilatory output and VO2, and lower PCO2, during constant work-rate exercise; the placebo and control groups did not show these changes. The perceived respiratory effort was unchanged in spite of the higher ventilation rate after training. Conclusions The results suggest that respiratory muscle endurance training improves cycling performance in fit, experienced cyclists. The relative hyperventilation with no change in respiratory effort sensations suggest that respiratory muscle training allows subjects to tolerate the higher exercise ventilatory response without more dyspnea. Whether or not this can explain the enhanced performance is unknown.

  11. The effect of beta-alanine supplementation on isokinetic force and cycling performance in highly trained cyclists.

    Science.gov (United States)

    Howe, Samuel T; Bellinger, Phillip M; Driller, Matthew W; Shing, Cecilia M; Fell, James W

    2013-12-01

    Beta-alanine may benefit short-duration, high-intensity exercise performance. The aim of this randomized double-blind placebo-controlled study was to examine the effects of beta-alanine supplementation on aspects of muscular performance in highly trained cyclists. Sixteen highly trained cyclists (mean ± SD; age = 24 ± 7 yr; mass = 70 ± 7 kg; VO2max = 67 ± 4 ml · kg(-1) · min(-1)) supplemented with either beta-alanine (n = 8, 65 mg · kg - 1BM) or a placebo (n = 8; dextrose monohydrate) over 4 weeks. Pre- and postsupplementation cyclists performed a 4-minute maximal cycling test to measure average power and 30 reciprocal maximal isokinetic knee contractions at a fixed angular velocity of 180° · sec(-1) to measure average power/repetition, total work done (TWD), and fatigue index (%). Blood pH, lactate (La-) and bicarbonate (HCO3-) concentrations were measured pre- and postisokinetic testing at baseline and following the supplementation period. Beta-alanine supplementation was 44% likely to increase average power output during the 4-minute cycling time trial when compared with the placebo, although this was not statistically significant (p = .25). Isokinetic average power/repetition was significantly increased post beta-alanine supplementation compared with placebo (beta-alanine: 6.8 ± 9.9 W, placebo: -4.3 ± 9.5 W, p = .04, 85% likely benefit), while fatigue index was significantly reduced (p = .03, 95% likely benefit). TWD was 89% likely to be improved following beta-alanine supplementation; however, this was not statistically significant (p = .09). There were no significant differences in blood pH, lactate, and HCO3- between groups (p > .05). Four weeks of beta-alanine supplementation resulted in worthwhile changes in time-trial performance and short-duration muscular force production in highly trained cyclists.

  12. Does respiratory muscle training increase physical performance?

    Science.gov (United States)

    Sperlich, Billy; Fricke, Hannes; de Marées, Markus; Linville, John W; Mester, Joachim

    2009-09-01

    Special force units and military personnel undergo demanding physical exercise and might benefit from high-intensity respiratory muscle training (RMT) by increasing their endurance performance. This study examined the effects of a 6-week high-intensity RMT on running performance and oxygen uptake (VO2max) in a group of German Special Force Squad members. 17 participants were randomly assigned to a training or control group. Baseline and post-testing included a ramp test, as well as an incremental test on a treadmill, performed to physical exhaustion. VO2, respiratory exchange ratio, and heart rate were measured breath by breath. Furthermore, maximum running speed (V(max)), 4 mmol x 1(-1) lactate threshold (V4) and perception of respiratory effort were determined. During pulmonary testing, sustained maximum inspiratory and expiratory pressure (PI(max) and PE(max)) were obtained. RMT was performed daily at approximately 90% PI(max) for 6 weeks with 2 x 30 breath cycles using an Ultrabreathe lung trainer. No statistical differences were detected between the groups for any parameter after RMT. High-intensity RMT did not show any benefits on VO2max and endurance performance and are unlikely to be of benefit to military or paramilitary training programs for an increase in endurance performance.

  13. VO2@RER1.0: a novel submaximal cardiopulmonary exercise index.

    Science.gov (United States)

    Chin, Clifford; Kazmucha, Jeffrey; Kim, Nancy; Suryani, Reny; Olson, Inger

    2010-01-01

    Maximal oxygen consumption (VO2max) is the "gold standard" by which to assess functional capacity; however, it is effort dependent. VO2@RER1.0 is defined when VO2 = VCO2. Between December 22, 1997 and November 9, 2004, 305 pediatric subjects underwent cycle ergometer cardiopulmonary exercise testing, exercised to exhaustion, and reached a peak respiratory exchange ratio > or = 1.10. Group 1 subjects achieved a peak VO2 > or = 80% of predicted VO2max; group 2 subjects achieved a peak VO2 equation was created. VO2@RER1.0 data from groups 2 and 3 were plotted onto the normative graph. Contingency table and relative-risk analysis showed that an abnormal VO2@RER1.0 predicted an abnormal peak VO2(positive-predictive value 83%, negative-predictive value 85%, sensitivity 84%, and specificity 84%). VO2@RER1.0 is a highly sensitive, specific, and predictive submaximal index of functional capacity. This submaximal index is easy to identify without subjectivity. This index may aid in the evaluation of subjects who cannot exercise to maximal parameters.

  14. Effect of previous exhaustive exercise on metabolism and fatigue development during intense exercise in humans

    DEFF Research Database (Denmark)

    Iaia, F. M.; Perez-Gomez, J.; Nordsborg, Nikolai;

    2010-01-01

    The present study examined how metabolic response and work capacity are affected by previous exhaustive exercise. Seven subjects performed an exhaustive cycle exercise ( approximately 130%-max; EX2) after warm-up (CON) and 2 min after an exhaustive bout at a very high (VH; approximately 30 s), high...... during a repeated high-intensity exercise lasting 1/2-2 min....

  15. The acute 1-week effects of the Zone diet on body composition, blood lipid levels, and performance in recreational endurance athletes.

    Science.gov (United States)

    Jarvis, Mark; McNaughton, Lars; Seddon, Alan; Thompson, Dylan

    2002-02-01

    The aim of this study was to examine the effects of a 7-day Zone diet compared with a normal diet on maximal oxygen uptake (V(O)2 max), running time to exhaustion during endurance performance, and body composition. Eight men, with the following physical characteristics (mean +/- SE), participated in this study: age, 26.1 +/- 1.9 years; height, 178 +/- 1.7 cm; mass, 70.7 +/- 2.1 kg; and V(O)2 max, 54.6 +/- 3.1 ml x kg(-1) x min(-1). All subjects undertook pretesting for V(O)2 max, time to exhaustion (80% V(O)2 max), and body composition (Biostat 1500) before following either the normal diet or the Zone diet for 7 days. These performance trials were performed before and after the dietary period. There was a significant (p diet to 1,994 +/- 438 kcal on the Zone diet. Subjects showed a significant reduction (p diet to 34.11 +/- 7.01 minutes for the Zone diet. In conclusion, the claim of the authors of the Zone diet that performance time and V(O)2 max can be improved was not shown in this 1-week research trial. We would suggest that this is not a nutritional strategy that athletes should use until further work has been conducted.

  16. Development of Exhaust Gas Driven Absorption Chiller-Heater

    Science.gov (United States)

    Inoue, Naoyuki; Endou, Tetsuya; Saito, Kiyoshi; Kawai, Sunao

    Waste heat from co-generation systems are usually recovered by hot water or steam, those are used to drive absorption refrigerators at cooling time, and those are used for heating via heat exchangers at heating time. However waste heat from micro gas turbines are discharged in the form of exhaust gas, it is simple that exhaust gas is directly supplied to absorption chiller-heaters. In the first report we studied cooling cycle, and this second paper, we evaluated various absorption heating cycles for exhaust gas driven absorption chiller-heaters, and adopted one of these cycles for the prototype machine. Also, we experimented with the prototype for wide range condition and got the heating characteristics. Based on the experimental data, we developed a simulation model of the static characteristics, and then studied how to increase the output by limited exhaust gas.

  17. Comparison of the 1.5 Mile Run Times at 7,200 Feet and Simulated 850 Feet in a Hyperoxic Room

    Science.gov (United States)

    2012-03-01

    review and Maximum oxygen uptake treadmill ( VO2 max ) test introduction 30 min – VO2 max ...Maximal Oxygen Update ( VO2 max ) Test ......................................... 7 Figure 3 - VO2 Max results for Male, Female and All Subjects. * p...0.001 between Male and Female VO2 ’s. ............................................................. 11 Figure 4 - VO2 Max vs Predicted VO2 Max at

  18. Aerobic capacity in persons with multiple sclerosis: a systematic review and meta-analysis.

    Science.gov (United States)

    Langeskov-Christensen, Martin; Heine, Martin; Kwakkel, Gert; Dalgas, Ulrik

    2015-06-01

    Aerobic capacity (VO2max) is a strong health and performance predictor and is regarded as a key physiological measure in the healthy population and in persons with multiple sclerosis (PwMS). However, no studies have tried to synthesize the existing knowledge regarding VO2max in PwMS. The objectives of this study were to (1) systematically review the psychometric properties of the VO2max test; (2) systematically review the literature on VO2max compared with healthy populations; (3) summarize correlates of VO2max; and (4) to review and conduct a meta-analysis of longitudinal exercise studies evaluating training-induced effects on VO2max in PwMS. A systematic literature search of six databases (PubMed, EMBASE, Cochrane Library, PEDro, CINAHL and SPORTDiscus) was performed. To be included, the study had to (1) enrol participants with definite MS according to defined criteria; (2) assess aerobic capacity (VO2max) by means of a graded exercise test to voluntary exhaustion; (3) had undergone peer review; and (4) be available in English, Danish or Dutch. The psychometric properties of the VO2max test in PwMS were reviewed with respect to reliability, validity and responsiveness. Simple Pearson correlation analysis was used to assess the relation between key study characteristics and the reported mean VO2max. The methodological quality of the intervention studies was evaluated using the original 11-item Physiotherapy Evidence Database (PEDro) scale. A random coefficient model was used to summarize individual, weighted, standardized effects of studies that assessed the effects of exercise on aerobic capacity in PwMS. A total of 40 studies, covering 165 healthy controls and 1,137 PwMS, fulfilled the inclusion criteria. VO2max testing in PwMS can be considered a valid measure of aerobic capacity, at least in PwMS having low-to-mild disability, and an ∼10% change between two tests performed on separate days can be considered the smallest reliable change (with 95% certainty

  19. Aerodynamic Control of Exhaust

    DEFF Research Database (Denmark)

    Hyldgård, Carl-Erik

    In the autumn of 1985 the Unive!Sity of Aalborg was approached by the manufacturer C. P. Aaberg, who had obtained aerodynilmic control of the exhaust by means of injection. The remaining investigations comprising optimizations of the system with regard to effect, consumption, requirements...

  20. Hyperventilation and exhaustion syndrome.

    Science.gov (United States)

    Ristiniemi, Heli; Perski, Aleksander; Lyskov, Eugene; Emtner, Margareta

    2014-12-01

    Chronic stress is among the most common diagnoses in Sweden, most commonly in the form of exhaustion syndrome (ICD-10 classification - F43.8). The majority of patients with this syndrome also have disturbed breathing (hyperventilation). The aim of this study was to investigate the association between hyperventilation and exhaustion syndrome. Thirty patients with exhaustion syndrome and 14 healthy subjects were evaluated with the Nijmegen Symptom Questionnaire (NQ). The participants completed questionnaires about exhaustion, mental state, sleep disturbance, pain and quality of life. The evaluation was repeated 4 weeks later, after half of the patients and healthy subjects had engaged in a therapy method called 'Grounding', a physical exercise inspired by African dance. The patients reported significantly higher levels of hyperventilation as compared to the healthy subjects. All patients' average score on NQ was 26.57 ± 10.98, while that of the healthy subjects was 15.14 ± 7.89 (t = -3.48, df = 42, p therapy such as Grounding.

  1. Hybrid Exhaust Component

    Science.gov (United States)

    Pelletier, Gerard D. (Inventor); Logan, Charles P. (Inventor); McEnerney, Bryan William (Inventor); Haynes, Jeffrey D. (Inventor)

    2015-01-01

    An exhaust includes a wall that has a first composite material having a first coefficient of thermal expansion and a second composite material having a second coefficient of the thermal expansion that is less than the first coefficient of thermal expansion.

  2. The Effects of a Duathlon Simulation on Ventilatory Threshold and Running Economy

    Directory of Open Access Journals (Sweden)

    Nathaniel T. Berry, Laurie Wideman, Edgar W. Shields, Claudio L. Battaglini

    2016-06-01

    Full Text Available Multisport events continue to grow in popularity among recreational, amateur, and professional athletes around the world. This study aimed to determine the compounding effects of the initial run and cycling legs of an International Triathlon Union (ITU Duathlon simulation on maximal oxygen uptake (VO2max, ventilatory threshold (VT and running economy (RE within a thermoneutral, laboratory controlled setting. Seven highly trained multisport athletes completed three trials; Trial-1 consisted of a speed only VO2max treadmill protocol (SOVO2max to determine VO2max, VT, and RE during a single-bout run; Trial-2 consisted of a 10 km run at 98% of VT followed by an incremental VO2max test on the cycle ergometer; Trial-3 consisted of a 10 km run and 30 km cycling bout at 98% of VT followed by a speed only treadmill test to determine the compounding effects of the initial legs of a duathlon on VO2max, VT, and RE. A repeated measures ANOVA was performed to determine differences between variables across trials. No difference in VO2max, VT (%VO2max, maximal HR, or maximal RPE was observed across trials. Oxygen consumption at VT was significantly lower during Trial-3 compared to Trial-1 (p = 0.01. This decrease was coupled with a significant reduction in running speed at VT (p = 0.015. A significant interaction between trial and running speed indicate that RE was significantly altered during Trial-3 compared to Trial-1 (p < 0.001. The first two legs of a laboratory based duathlon simulation negatively impact VT and RE. Our findings may provide a useful method to evaluate multisport athletes since a single-bout incremental treadmill test fails to reveal important alterations in physiological thresholds.

  3. The relationship of the 6-min walk test to maximal oxygen consumption in transplant candidates with end-stage lung disease.

    Science.gov (United States)

    Cahalin, L; Pappagianopoulos, P; Prevost, S; Wain, J; Ginns, L

    1995-08-01

    To assess the relationship of distance ambulated during the 6-min walk test (6'WT) to maximal oxygen consumption (VO2 max). Multivariate analysis of patient characteristics to VO2 max. Pre-lung transplant evaluation. 60 patients (22 men, 38 women; mean age, 44 years) with end-stage lung disease (mean FEV1 and forced vital capacity of 0.97 and 1.93, respectively). The 6'WT was performed on a level hallway surface, and VO2 max was obtained during maximal cycle ergometry exercise testing with respiratory gas analysis. Multivariate analysis of patient characteristics (age, sex, weight, FEV1, FVC, diffusing capacity for carbon monoxide (DCO), 6'WT distance ambulated, number of rests per 6'WT, and the maximal heart rate, blood pressure, rate-pressure product, respiratory rate, oxygen saturation, rating of perceived exertion, and amount of supplemental oxygen used during the 6'WT) was performed on two groups of 30 patients each (group A or B) who were randomly assigned to either group by a process of random selection using a computer-generated random numbers program. Distance ambulated was the strongest independent predictor of VO2 max (r = 0.73; p test results (FVC, FEV1, and DCO) to the regression equation increased the correlation coefficient to 0.83. Because of the significant correlation of distance ambulated during the 6'WT to VO2 max, the prediction equation obtained from the multivariate analysis of group A, VO2 max = 0.006 x distance (feet) +3.38, was used to estimate the VO2 max of the group B patients. No significant difference was observed between the estimated (x +/- SD = 8.9 +/- 2.4 mL/kg/min) and observed (x +/- SD = 9.4 +/- 3.8 mL/kg/min) VO2 max (mean difference, 0.5 mL/kg/min; SD of the difference = 2.88). The distance ambulated during a 6'WT can predict VO2 max in patients with end-stage lung disease. The addition of several patient characteristics can increase the ability to predict VO2 max and account for more of the variability. Such information is

  4. Single and Combined Effects of Beetroot Crystals and Sodium Bicarbonate on 4-km Cycling Time Trial Performance.

    Science.gov (United States)

    Callahan, Marcus J; Parr, Evelyn B; Hawley, John A; Burke, Louise M

    2017-06-01

    When ingested alone, beetroot juice and sodium bicarbonate are ergogenic for high-intensity exercise performance. This study sought to determine the independent and combined effects of these supplements. Eight endurance trained (VO2max 65 mL·kg·min(-1)) male cyclists completed four × 4-km time trials (TT) in a doubleblind Latin square design supplementing with beetroot crystals (BC) for 3 days (15 g·day(-1) + 15 g 1 h before TT, containing 300 mg nitrate per 15 g), bicarbonate (Bi 0.3 g·kg(-1) body mass [BM] in 5 doses every 15 min from 2.5 h before TT); BC+Bi or placebo (PLA). Subjects completed TTs on a Velotron cycle ergometer under standardized laboratory conditions. Plasma nitrite concentrations were significantly elevated only in the BC+Bi trial before the TT (1520 ± 786 nmol·L(-1)) compared with baseline (665 ± 535 nmol·L(-1), p = .02) and the Bi and PLA conditions (Bi: 593 ± 203 nmol·L(-1), p .05). Blood bicarbonate concentrations were increased in the BC+Bi and Bi trials before the TT (BC+Bi: 30.9 ± 2.8 mmol·L(-1); Bi: 31.7 ± 1.1 mmol·L(-1)). There were no differences in mean power output (386-394 W) or the time taken to complete the TT (335.8-338.1 s) between any conditions. Under the conditions of this study, supplementation was not ergogenic for 4-km TT performance.

  5. Ageing characterization of exhaust flexible couplings

    OpenAIRE

    2012-01-01

    The aim of this work is to investigate the mechanical strength of automotive exhaust flexible couplings subjected to thermo-mechanical fatigue and corrosion. Five different types of flexible coupling have been considered, realised by four different king of materials: three stainless steels (AISI 309, AISI 321, AISI 321 Ti) and a nickel alloy (Incoloy 825). These components have been tested by a dedicated procedure consisting of different cycles of fatigue, heating and corrosion. Performances ...

  6. Influence of age in estimating maximal oxygen uptake.

    Science.gov (United States)

    de Souza E Silva, Christina G; Franklin, Barry A; Forman, Daniel E; Araújo, Claudio Gil S

    2016-02-01

    To assess the influence of age on the error of estimate (EE) of maximal oxygen uptake (VO2max) using sex and population specific-equations in cycle ergometer exercise testing, since estimated VO2 max is associated with a substantial EE, often exceeding 20%, possibly due to intrinsic variability of mechanical efficiency. 1850 adults (68% men), aged 18 to 91 years, underwent maximal cycle ergometer cardiopulmonary exercise testing. Cardiorespiratory fitness (CRF) was assessed relative to sex and age [younger (18 to 35 years), middle-aged (36 to 60 years) and older (> 60 years)]. VO2max [mL·(kg·min)(-1)] was directly measured by assessment of gas exchange and estimated using sex and population specific-equations. Measured and estimated values of VO2max and related EE were compared among the three age- and sex-specific groups. Directly measured VO2max of men and women were 29.5 ± 10.5 mL·(kg·min)(-1) and 24.2 ± 9.0 mL·(kg·min)(-1) (P 0.05), respectively. EE and %E for each age-group were, respectively, for men: younger = 1.9 ± 4.1 mL·(kg·min)(-1) and 3.8 ± 10.5%, middle-aged = 0.6 ± 3.1 mL·(kg·min)(-1) and 0.4 ± 10.3%, older = -0.2 ± 2.7 mL·(kg·min)(-1) and -4.2 ± 16.6% (P VO2max were underestimated in younger age-groups and were overestimated in older age groups. Age significantly influences the magnitude of the EE of VO2max in both men and women and should be considered when CRF is estimated using population specific equations, rather than directly measured.

  7. Validity of submaximal exercise testing in adults with athetospastic cerebral palsy.

    Science.gov (United States)

    Satonaka, Ayako; Suzuki, Nobuharu; Kawamura, Morio

    2012-03-01

    To examine the validity of the multistage submaximal cycle ergometer test for adults with athetospastic cerebral palsy. Cross-sectional and correlative study. Oxygen uptake and heart rates were recorded while the participants underwent the maximal cycle ergometer test and the multistage submaximal cycle ergometer test. Peak oxygen consumption (Vo(2)peak) was achieved by the maximal cycle test. Maximum oxygen consumption (VO(2)max) was predicted by the multistage submaximal cycle ergometer test. Research laboratory setting. Adults with athetospastic cerebral palsy (N=16; 10 women and 6 men; mean age ± SD, 43.7±14.5y). Not applicable. Peak VO(2) was compared with the predicted VO(2)max. Mean VO(2)peak and the predicted VO(2)max ± SD were 866.9±202.9 mL/min(-1) and 857.4±248.4 mL/min(-1), respectively. There was not a significant difference between VO(2)peak values and the predicted VO(2)max values (r=.28). And there was a significant correlation between VO(2)peak values and the predicted VO(2)max values (r=.94, Pcerebral palsy. Copyright © 2012 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  8. A PILOT STUDY COMPARING TWO FIELD TESTS WITH THE TREADMILL RUN TEST IN SOCCER PLAYERS

    Directory of Open Access Journals (Sweden)

    Abdul Rashid Aziz

    2005-06-01

    Full Text Available This study compares the performances obtained during soccer-specific field tests of the 20 m multistage shuttle run test (MST and the Yo-Yo intermittent endurance test (YIET, with the measured maximal oxygen uptake (VO2max obtained in both field tests as well as that obtained in the traditional test of running to exhaustion on a treadmill (TRT, in young trained soccer players. Twenty-one National-level youth players performed, in random order, the MST and YIET to determine the relationship between the two field tests. From these, eight randomly chosen players performed their field tests as well as a TRT, equipped with an ambulatory gas exchange measurement device. Pearson correlation coefficient analysis showed that the players' performance (i.e. distance covered in the MST and YIET was correlated (r = 0.65, p 0.05. In contrast, significant correlations were observed between the players' performance in the MST with the measured VO2max obtained in the same MST and in the YIET (both p < 0.05; and attained almost statistical significance with the measured VO2max in the TRT (p = 0.06. The lack of association between distances covered in the YIET with all the measured VO2max values suggest that measured VO2max per se may not be suitable to characterize soccer players' intermittent endurance performance. In comparison with the MST, the YIET may be a more favourable field-based assessment of soccer player's endurance performance

  9. Local Pain Dynamics during Constant Exhaustive Exercise.

    Science.gov (United States)

    Slapsinskaite, Agne; Razon, Selen; Balagué Serre, Natàlia; Hristovski, Robert; Tenenbaum, Gershon

    2015-01-01

    The purpose of this study was to delineate the topological dynamics of pain and discomfort during constant exercise performed until volitional exhaustion. Eleven physical education students were tested while cycling and running at a "hard" intensity level (e.g., corresponding to Borg's RPE (6-20) = 15). During the tests, participants reported their discomfort and pain on a body map every 15s. "Time on task" for each participant was divided into five equal non-overlapping temporal windows within which their ratings were considered for analysis. The analyses revealed that the number of body locations with perceived pain and discomfort increased throughout the five temporal windows until reaching the mean (± SE) values of 4.2 ± 0.7 and 4.1 ± 0.6 in cycling and running, respectively. The dominant locations included the quadriceps and hamstrings during cycling and quadriceps and chest during running. In conclusion, pain seemed to spread throughout the body during constant cycling and running performed up to volitional exhaustion with differences between cycling and running in the upper body but not in the lower body dynamics.

  10. Local Pain Dynamics during Constant Exhaustive Exercise.

    Directory of Open Access Journals (Sweden)

    Agne Slapsinskaite

    Full Text Available The purpose of this study was to delineate the topological dynamics of pain and discomfort during constant exercise performed until volitional exhaustion. Eleven physical education students were tested while cycling and running at a "hard" intensity level (e.g., corresponding to Borg's RPE (6-20 = 15. During the tests, participants reported their discomfort and pain on a body map every 15s. "Time on task" for each participant was divided into five equal non-overlapping temporal windows within which their ratings were considered for analysis. The analyses revealed that the number of body locations with perceived pain and discomfort increased throughout the five temporal windows until reaching the mean (± SE values of 4.2 ± 0.7 and 4.1 ± 0.6 in cycling and running, respectively. The dominant locations included the quadriceps and hamstrings during cycling and quadriceps and chest during running. In conclusion, pain seemed to spread throughout the body during constant cycling and running performed up to volitional exhaustion with differences between cycling and running in the upper body but not in the lower body dynamics.

  11. Low-pressure-ratio regenerative exhaust-heated gas turbine

    Energy Technology Data Exchange (ETDEWEB)

    Tampe, L.A.; Frenkel, R.G.; Kowalick, D.J.; Nahatis, H.M.; Silverstein, S.M.; Wilson, D.G.

    1991-01-01

    A design study of coal-burning gas-turbine engines using the exhaust-heated cycle and state-of-the-art components has been completed. In addition, some initial experiments on a type of rotary ceramic-matrix regenerator that would be used to transfer heat from the products of coal combustion in the hot turbine exhaust to the cool compressed air have been conducted. Highly favorable results have been obtained on all aspects on which definite conclusions could be drawn.

  12. Measures of cardiorespiratory fitness in relation to measures of body size and composition among children.

    Science.gov (United States)

    Tompuri, Tuomo; Lintu, Niina; Savonen, Kai; Laitinen, Tomi; Laaksonen, David; Jääskeläinen, Jarmo; Lakka, Timo A

    2015-11-01

    In the exercise testing measures of cardiorespiratory fitness need to be scaled by body size or composition to enable comparison between individuals. Traditionally used weight-proportional measures are potentially confounded by body adiposity that hampers their interpretation and applicability in the clinical assessment of cardiorespiratory fitness. We aimed to find the most appropriate measure of body size or composition for scaling of measures of cardiorespiratory fitness among children. We assessed body weight and height, maximal workload (W MAX ) and maximal oxygen uptake (VO2 MAX ) using cycle ergometer exercise test with respiratory gas analysis and body lean mass (LM) and fat mass (FM) by dual-energy X-ray absorptiometry and by bioimpedance analysis among 38 children. The data were analysed using Pearson's coefficients for correlation and stepwise linear regression models. Lean mass (r > 0.54) and height (r > 0.51) had stronger positive correlations with absolute W MAX and VO2 MAX than weight (r > 0.30) in girls and boys. None of the measures of body size or composition correlated with LM-proportional W MAX or VO2 MAX in girls or boys. Only LM correlated positively with height-proportional W MAX (r = 0.65) and VO2 MAX (r = 0.71) in boys. FM correlated negatively with weight-proportional W MAX (r VO2 MAX (r MAX (β = -0.68) and VO2 MAX (β = -0.61) than exercise performance in multivariate linear regression models. While assessing cardiorespiratory fitness, LM is the most appropriate measure of body size or composition for scaling of W MAX and VO2 MAX, because scaling by body weight introduces confounding by body adiposity. © 2014 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  13. Velocidade de corrida associada ao consumo máximo de oxigênio em meninos de 10 a 15 anos Running speed associated with maximal oxygen uptake in boys aged 10 to 15 years

    Directory of Open Access Journals (Sweden)

    Fabiana Andrade Machado

    2002-02-01

    chronological age and biological maturation on the maximal oxygen uptake (VO2max and the speed corresponding to the VO2max in Brazilian boys aged 10-15 years under no regular training program. Forty volunteers participated in this study. They were divided into groups by chronological age (GC1 - n = 20; 11.45 ± 0.63 years; 38.8 ± 8.6 kg; 143.6 ± 8.2 cm; and GC2 - n = 20; 14.1 ±0.6 years; 55.9 ± 14.2 kg; 163.3 ± 10.2 cm and by biological maturation (GB1 - n = 20; stages 1, 2, 3, and GB2 - n = 20; stages 4, 5. The VO2max was determined with a progressive and intermittent test in a treadmill, starting from a speed of 9 km/h and increasing 1 km/h each 3 minutes until volunteer exhaustion. The speed at VO2max (vVO2max was the lowest speed that elicited VO2max (peak value. The Va max was calculated in accordance with di Prampero (1986. There was a significant difference of VO2max (l/min, Va max (km/h and vVO2max (km/h between GC1 and GC2 (1.84 ± 0.41 / 2.81 ± 0.61; 11.8 ± 1.2 / 12.6 ± 1.2; 12.1 ± 1.2 / 12.9 ± 1.1, respectively; GB1 and GB2 (1.8 ± 0.37 / 2.87 ± 0.56; 12.1 ± 1.2 / 12.9 ± 1.1; 12.5 ± 1.1, respectively, but there was no significant difference of VO2max (ml.kg-1.min-1 between groups (GC1 and GC2; GB1 and GB2. The authors can conclude that the VO2max, Va max and vVO2max had their values increased probably by growth and development processes, and can also express a better economy of movement, even in individuals not involved in a regular training program.

  14. The Effectiveness of a Pre-Exercise Performance Drink (PRX) on Indices of Maximal Cardiorespiratory Fitness.

    Science.gov (United States)

    Byars, Allyn; Greenwood, Mike; Greenwood, Lori; Simpson, Warren K

    2006-06-12

    This study examined the effectiveness of a pre-exercise drink (PRX) called EM.PACT on indices of maximal cardiorespiratory fitness. Twenty-four males (n = 12) and females (n = 12) ages 18-24 years (20.25 + 1.42), volunteered as subjects. Each subject performed two randomized trials of a VO2max treadmill test within a week of each other. Subjects in this randomized, placebo controlled, counter balanced, crossover design, ingested either a placebo (water) or PRX 20 minutes before each exercise bout. VO2max and time to exhaustion (Time) during graded exercise testing were evaluated. Using paired samples t-tests, significantly greater mean values were found in VO2max and Time for the PRX trial compared to the placebo trial (p PRX prior to exercise testing. The combined results of this investigation may provide meaningful practical applications for coaches and athletes alike regarding ergogenic hydration options.

  15. Endurance training of respiratory muscles improves cycling performance in fit young cyclists

    OpenAIRE

    Holm Paige; Sattler Angela; Fregosi Ralph F

    2004-01-01

    Abstract Background Whether or not isolated endurance training of the respiratory muscles improves whole-body endurance exercise performance is controversial, with some studies reporting enhancements of 50 % or more, and others reporting no change. Twenty fit (VO2 max 56.0 ml/kg/min), experienced cyclists were randomly assigned to three groups. The experimental group (n = 10) trained their respiratory muscles via 20, 45 min sessions of hyperpnea. The placebo group (n = 4) underwent "sham" tra...

  16. Timing the arrival at 2340m altitude for aerobic performance

    DEFF Research Database (Denmark)

    Schuler, B; Thomsen, JJ; Gassmann, M

    2007-01-01

    This study tested the hypothesis that maximal oxygen uptake (VO2max) and performance increase upon altitude acclimatization at moderate altitude. Eight elite cyclists were studied at sea level, and after 1 (Day 1), 7 (Day 7), 14 (Day 14) and 21 (Day 21) days of exposure to 2340 m. Capillary blood...... samples were taken on these days before performing two consecutive maximal exercise trials. Acclimatization reased hemoglobin concentration and arterial oxygen content. On Day 1, VO2max and time to exhaustion (at 80% of sea-level maximal power output) decreased by 12.8% (P

  17. Visual Impairment does not Limit Training Effects in Development of Aerobic and Anaerobic Capacity in Tandem Cyclists

    Directory of Open Access Journals (Sweden)

    Malwina Kamelska Anna

    2015-12-01

    Full Text Available The study aimed to investigate the differences in the effects of 7-month training on aerobic and anaerobic capacity in tandem cycling athletes with and without visual impairment. In this study, Polish elite (n=13 and sub-elite (n=13 visually impaired (VI (n=13; 40.8 ±12.8 years and properly sighted (PS (n=13; 36.7 ±12.2 years tandem-cycling athletes participated voluntarily in 7-month routine training. The following pre-/post-training measurements were conducted on separate days: maximal oxygen uptake (VO2max was estimated with age correction using the Physical Working Capacity test on a bicycle ergometer according to the Astrand-Ryhming method. Maximal power output (Pmax was evaluated using the Quebec test on a bicycle ergometer. At baseline, VO2max (47.8 ±14.1 vs 42.0 ±8.3 ml/kg/min, respectively and Pmax (11.5 ±1.5 vs 11.5 ±1.0 W/kg did not differ significantly between PS and VI cyclists. However, differences in aerobic capacity were considered as clinically significant. Two-way ANOVA revealed that after 7 month training, there were statistically significant increases in VO2max (p=0.003 and Pmax (p=0.009 among VI (VO2max, +9.1%; Pmax, +6.3% and PS (VO2max, +9.1%; Pmax, +11.7% cyclists, however, no time x visual impairment interaction effect was found (VO2max, p=0.467; Pmax, p=0.364. After training, VO2max (p=0.03, but not Pmax (p=0.13, was significantly greater in elite compared to sub-elite tandem cyclists. VI and PS tandem cyclists showed similar rates of improvement in VO2max and Pmax after 7-month training. VO2max was a significant determinant of success in tandem cycling. This is one of the first studies providing reference values for aerobic and anaerobic capacity in visually impaired cyclists.

  18. Visual Impairment does not Limit Training Effects in Development of Aerobic and Anaerobic Capacity in Tandem Cyclists.

    Science.gov (United States)

    Malwina, Kamelska Anna; Krzysztof, Mazurek; Piotr, Zmijewski

    2015-11-22

    The study aimed to investigate the differences in the effects of 7-month training on aerobic and anaerobic capacity in tandem cycling athletes with and without visual impairment. In this study, Polish elite (n=13) and sub-elite (n=13) visually impaired (VI) (n=13; 40.8 ±12.8 years) and properly sighted (PS) (n=13; 36.7 ±12.2 years) tandem-cycling athletes participated voluntarily in 7-month routine training. The following pre-/post-training measurements were conducted on separate days: maximal oxygen uptake (VO2max) was estimated with age correction using the Physical Working Capacity test on a bicycle ergometer according to the Astrand-Ryhming method. Maximal power output (Pmax) was evaluated using the Quebec test on a bicycle ergometer. At baseline, VO2max (47.8 ±14.1 vs 42.0 ±8.3 ml/kg/min, respectively) and Pmax (11.5 ±1.5 vs 11.5 ±1.0 W/kg) did not differ significantly between PS and VI cyclists. However, differences in aerobic capacity were considered as clinically significant. Two-way ANOVA revealed that after 7 month training, there were statistically significant increases in VO2max (p=0.003) and Pmax (p=0.009) among VI (VO2max, +9.1%; Pmax, +6.3%) and PS (VO2max, +9.1%; Pmax, +11.7%) cyclists, however, no time × visual impairment interaction effect was found (VO2max, p=0.467; Pmax, p=0.364). After training, VO2max (p=0.03), but not Pmax (p=0.13), was significantly greater in elite compared to sub-elite tandem cyclists. VI and PS tandem cyclists showed similar rates of improvement in VO2max and Pmax after 7-month training. VO2max was a significant determinant of success in tandem cycling. This is one of the first studies providing reference values for aerobic and anaerobic capacity in visually impaired cyclists.

  19. Intrinsic motivation in two exercise interventions: Associations with fitness and body composition.

    Science.gov (United States)

    Thøgersen-Ntoumani, Cecilie; Shepherd, Sam O; Ntoumanis, Nikos; Wagenmakers, Anton J M; Shaw, Christopher S

    2016-02-01

    To examine the motivational process through which increases in aerobic capacity and decreases in total body fat are achieved during high-intensity intermittent training (HIT) and moderate-intensity continuous training (MICT) interventions. Eighty-seven physically inactive adults (65% women, age = 42 ± 12, BMI = 27.67 ± 4.99 kg/m²) took part in a 10-week randomized intervention testing group-based HIT, operationalized as repeated sprints of 15-60 s interspersed with periods of recovery cycling ≤ 25 min/session, 3 sessions/wk⁻¹, or MICT, operationalized as cycling at constant workload of ∼65% maximum aerobic capacity (VO2max, 30-45 min/session⁻¹, 5 sessions/wk⁻¹. Assessments of VO2max and total body fat were made pre- and postintervention. Motivation variables were assessed midintervention and class attendance was monitored throughout. Path analysis was employed, controlling for treatment arm and baseline values of VO2max and total body fat. The 2 groups differed in adherence only, favoring HIT. Baseline VO2max predicted intrinsic motivation midintervention. Intrinsic motivation predicted program adherence, which in turn predicted increases in VO2max and decreases in total body fat by the end of the study. Intrinsic motivation in HIT and MICT is positively linked to adherence to these programs, which can facilitate improvements in fitness and body composition. (c) 2016 APA, all rights reserved).

  20. Turbine exhaust pressure measurements

    Energy Technology Data Exchange (ETDEWEB)

    Burns, J.M. [Stone & Webster Engineering Corp., Boston, MA (United States); Hernandez, E. [Community Energy Alternatives Inc., Ridgewood, NJ (United States)

    1996-05-01

    This paper discusses the dynamic operating environment in the turbine-condenser steam space and the two sensors, basket tips and guideplates, that have been approved by ASME test codes for measurement of the static pressure within that exhaust region. It defines the rigorous geometry and construction requirements of these sensors in order that they be acceptable for guarantee/acceptance testing. The paper also offers a practical alternative to the classical ASME PTC 6 (Turbine Test Code) basket tip design that is easier to fabricate in the typical utility machine shop. The alternative design makes it less expensive, much faster to construct, and facilitates the drainage of any accumulated condensate. Comparative field tests by PSE&G`s Research and Testing Laboratory conducted in 1995 at the 300 MW Mercer Generating Station, Unit 1 will be described which demonstrate the modified basket tip pressure measurements are statistically indistinguishable from those of the PTC 6 design. Noting that basket tip turbine exhaust static pressure sensors are recommended by all the major U.S. turbine manufacturers, the paper also presents the limited available history of the empirical basket tip and the lack of any documented calibration history related to the accuracy of the guideplate. Finally, based on the success of this one basket tip variation, the paper concludes that other even more suitable designs could be developed by further research.

  1. A low carbohydrate-protein supplement improves endurance performance in female athletes.

    Science.gov (United States)

    McCleave, Erin L; Ferguson-Stegall, Lisa; Ding, Zhenping; Doerner, Phillip G; Wang, Bei; Kammer, Lynne M; Ivy, John L

    2011-04-01

    The purpose of this study was to investigate if a low mixed carbohydrate (CHO) plus moderate protein (PRO) supplement, provided during endurance exercise, would improve time to exhaustion (TTE) in comparison to a traditional 6% CHO supplement. Fourteen (n = 14) trained female cyclists and triathletes cycled on 2 separate occasions for 3 hours at intensities varying between 45 and 70% VO2max, followed by a ride to exhaustion at an intensity approximating the individual's ventilatory threshold average 75.06% VO2max. Supplements (275 mL) were provided every 20 minutes during exercise and were composed of a CHO mixture (1% each of dextrose, fructose, and maltodextrin) + 1.2% PRO (CHO + PRO) or 6% dextrose only (CHO). The TTE was significantly greater with CHO + PRO in comparison to with CHO (49.94 ± 7.01 vs. 42.36 ± 6.21 minutes, respectively, p < 0.05). Blood glucose was significantly lower during the CHO + PRO trial (4.07 ± 0.12 mmol · L(-1)) compared to during the CHO trial (4.47 ± 0.12 mmol · L(-1)), with treatment × time interactions occurring from 118 minutes of exercise until exhaustion (p < 0.05). Results from the present study suggest that the addition of a moderate amount of PRO to a low mixed CHO supplement improves endurance performance in women above that of a traditional 6% CHO supplement. Improvement in performance occurred despite CHO + PRO containing a lower CHO and caloric content. It is likely that the greater performance seen with CHO + PRO was a result of the CHO-PRO combination and the use of a mixture of CHO sources.

  2. Running on a lower-body positive pressure treadmill

    DEFF Research Database (Denmark)

    Raffalt, Peter C; Hovgaard-Hansen, Line; Jensen, Bente Rona

    2013-01-01

    This study investigated maximal oxygen consumption (VO2max) and time to exhaustion while running on a lower-body positive pressure treadmill (LBPPT) at normal body weight (BW) as well as how BW support affects respiratory responses, ground reaction forces, and stride characteristics....

  3. Combined inhalation of beta2 -agonists improves swim ergometer sprint performance but not high-intensity swim performance

    DEFF Research Database (Denmark)

    Kalsen, Anders; Hostrup, Morten; Bangsbo, Jens

    2014-01-01

    ), in permitted doses within the World Anti-Doping Agency 2013 prohibited list, in elite swimmers with (AHR, n = 13) or without (non-AHR, n = 17) AHR. Maximal voluntary isometric contraction of m. quadriceps (MVC), sprint performance on a swim ergometer and performance in an exhaustive swim test at 110% of VO2max...

  4. Effects of dehydration and fluid ingestion on cognition.

    Science.gov (United States)

    Tomporowski, P D; Beasman, K; Ganio, M S; Cureton, K

    2007-10-01

    The effects of exercise-induced dehydration and fluid ingestion on men's cognitive performance were assessed. Eleven young men attended separate sessions in which each individual cycled in a controlled environment at 60 % of V.O (2max) for periods of 15, 60, or 120 min without fluid replacement or 120 min with fluid replacement. Immediately following the assigned submaximal exercise period, the participant completed a graded exercise test to voluntary exhaustion. An executive processing test and a short-term memory test were performed prior to and immediately following exercise. Choice-response times during the executive processing test decreased following exercise, regardless of the level of dehydration. Choice-response errors increased following exercise, but only on trials requiring set shifting. Short-term memory performance improved following exercise, regardless of the level of dehydration. Changes in cognitive performance following exercise are hypothesized to be related to metabolic arousal following strenuous physical activity.

  5. Exercise increases sphingoid base-1-phosphate levels in human blood and skeletal muscle in a time- and intensity-dependent manner

    DEFF Research Database (Denmark)

    Baranowski, Marcin; Błachnio-Zabielska, Agnieszka U; Charmas, Małgorzata

    2015-01-01

    PURPOSE: Sphingosine-1-phosphate (S1P) regulates cardiovascular function and plays an important role in muscle biology. We have previously reported that cycling exercise increased plasma S1P. Here, we investigated the effect of exercise duration and intensity on plasma and skeletal muscle S1P...... levels. METHODS: In the first experiment, 13 male athletes performed a 60-min exercise at 65 % of VO2max and a graded exercise until exhaustion on a rowing ergometer. Samples of the venous blood were taken, and plasma, erythrocytes and platelets were isolated. In the second experiment, ten male...... moderately active subjects performed three consecutive periods of one-leg knee extension exercise (at 25, 55 and 85 % of the maximal workload). Muscle biopsies and blood samples from the radial artery and femoral veins were taken. RESULTS: Under basal conditions, S1P was released from the leg, as its...

  6. Exercise performance and cardiovascular health variables in 70-year-old male soccer players compared to endurance-trained, strength-trained and untrained age-matched men.

    Science.gov (United States)

    Randers, Morten Bredsgaard; Andersen, Jesper L; Petersen, Jesper; Sundstrup, Emil; Jakobsen, Markus D; Bangsbo, Jens; Saltin, Bengt; Krustrup, Peter

    2014-01-01

    The aim was to investigate performance variables and indicators of cardiovascular health profile in elderly soccer players (SP, n = 11) compared to endurance-trained (ET, n = 8), strength-trained (ST, n = 7) and untrained (UT, n = 7) age-matched men. The 33 men aged 65-85 years underwent a testing protocol including measurements of cycle performance, maximal oxygen uptake (VO2max) and body composition, and muscle fibre types and capillarisation were determined from m. vastus lateralis biopsy. In SP, time to exhaustion was longer (16.3 ± 2.0 min; P exercise performance and cardiovascular health profile are markedly better for lifelong trained SP than for age-matched UT controls. Incremental exercise capacity and muscle aerobic capacity of SP are also superior to lifelong ST athletes and comparable to endurance athletes.

  7. Maximal strength, muscular endurance and inflammatory biomarkers in young adult men.

    Science.gov (United States)

    Vaara, J P; Vasankari, T; Fogelholm, M; Häkkinen, K; Santtila, M; Kyröläinen, H

    2014-12-01

    The aim was to study associations of maximal strength and muscular endurance with inflammatory biomarkers independent of cardiorespiratory fitness in those with and without abdominal obesity. 686 young healthy men participated (25±5 years). Maximal strength was measured via isometric testing using dynamo-meters to determine maximal strength index. Muscular endurance index consisted of push-ups, sit-ups and repeated squats. An indirect cycle ergometer test until exhaustion was used to estimate maximal aerobic capacity (VO2max). Participants were stratified according to those with (>102 cm) and those without abdominal obesity (obesity (β=-0.08, -0.14, respectively) (pobesity (β=-0.11, -0.26, respectively) (p<0.05). This cross-sectional study demonstrated that muscular fitness is inversely associated with C-reactive protein and IL-6 concentrations in young adult men independent of cardiorespi-ratory fitness.

  8. Understanding Exhaustive Pattern Learning

    CERN Document Server

    Shen, Libin

    2011-01-01

    Pattern learning in an important problem in Natural Language Processing (NLP). Some exhaustive pattern learning (EPL) methods (Bod, 1992) were proved to be flawed (Johnson, 2002), while similar algorithms (Och and Ney, 2004) showed great advantages on other tasks, such as machine translation. In this article, we first formalize EPL, and then show that the probability given by an EPL model is constant-factor approximation of the probability given by an ensemble method that integrates exponential number of models obtained with various segmentations of the training data. This work for the first time provides theoretical justification for the widely used EPL algorithm in NLP, which was previously viewed as a flawed heuristic method. Better understanding of EPL may lead to improved pattern learning algorithms in future.

  9. Preliminary Modelling Results for an Otto Cycle/Stirling Cycle Hybrid-engine-based Power Generation System

    OpenAIRE

    Cullen, Barry; McGovern, Jim; Feidt, Michel; Petrescu, Stoian

    2009-01-01

    This paper presents preliminary data and results for a system mathematical model for a proposed Otto Cycle / Stirling Cycle hybrid-engine-based power generation system. The system is a combined cycle system with the Stirling cycle machine operating as a bottoming cycle on the Otto cycle exhaust. The application considered is that of a stationary power generation scenario wherein the Stirling cycle engine operates as a waste heat recovery device on the exhaust stream of the Otto cycle engine. ...

  10. Effects of aerobic fitness on oxygen uptake kinetics in heavy intensity swimming.

    Science.gov (United States)

    Reis, Joana F; Alves, Francisco B; Bruno, Paula M; Vleck, Veronica; Millet, Gregoire P

    2012-05-01

    This study aimed to characterise both the VO2 kinetics within constant heavy-intensity swimming exercise, and to assess the relationships between VO2 kinetics and other parameters of aerobic fitness, in well-trained swimmers. On separate days, 21 male swimmers completed: (1) an incremental swimming test to determine their maximal oxygen uptake (VO2 max), first ventilatory threshold (VT), and the velocity associated with VO2max (vVO(2 max)) and (2) two square-wave transitions from rest to heavy-intensity exercise, to determine their VO2 kinetics. All the tests involved breath-by-breath analysis of freestyle swimming using a swimming snorkel. VO2 kinetics was modelled with two exponential functions. The mean values for the incremental test were 56.0 ± 6.0 ml min(-1) kg(-1), 1.45 ± 0.08 m s(-1); and 42.1 ± 5.7 ml min(-1) kg(-1) for VO2 max, vVO(2 max) and VT, respectively. For the square-wave transition, the time constant of the primary phase (sp) averaged 17.3 ± 5.4 s and the relevant slow component (A'sc) averaged 4.8 ± 2.9 ml min(-1) kg(-1) [representing 8.9% of the end-exercise VO2 (%A'sc)]. sp was correlated with vVO(2 max) (r = -0.55, P = 0.01), but not with either VO2max (r = 0.05, ns) or VT (r = 0.14, ns). The %A' sc did not correlate with either VO2max (r = -0.14, ns) or vVO(2 max) (r = 0.06, ns), but was inversely related with VT (r = -0.61, P VO2 kinetics in heavy-intensity swimming using specific swimming exercise and appropriate methods. As has been demonstrated in cycling, faster VO2 kinetics allow higher aerobic power outputs to be attained. The slow component seems to be reduced in swimmers with higher ventilatory thresholds.

  11. 14 CFR 27.1123 - Exhaust piping.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Exhaust piping. 27.1123 Section 27.1123... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Exhaust System § 27.1123 Exhaust piping. (a) Exhaust piping... operating temperatures. (b) Exhaust piping must be supported to withstand any vibration and inertia loads...

  12. Effects of eight-week supplementation of Ashwagandha on cardiorespiratory endurance in elite Indian cyclists

    Science.gov (United States)

    Shenoy, Shweta; Chaskar, Udesh; Sandhu, Jaspal S.; Paadhi, Madan Mohan

    2012-01-01

    Background: Cycling is an endurance sport relying mainly on aerobic capacity to provide fuel during long-duration cycling events. Athletes are constantly searching for new methods to improve this capacity through various nutritional and ergogenic aids.s Purpose: The aim of the study was to find out the effect of Ashwagandha on the cardiorespiratory endurance capacity, that is, aerobic capacity of elite Indian cyclists. Materials and Methods: Forty elite (elite here refers to the participation of the athlete in at least state-level events) Indian cyclists were chosen randomly and were equally divided into experimental and placebo groups. The experimental group received 500 mg capsules of aqueous roots of Ashwagandha twice daily for eight weeks, whereas the placebo group received starch capsules. Outcome Measures: The baseline treadmill test for the cyclists were performed to measure their aerobic capacity in terms of maximal aerobic capacity (VO2 max), metabolic equivalent, respiratory exchange ratio (RER), and total time for the athlete to reach his exhaustion stage. After eight weeks of supplementation, the treadmill test was again performed and results were obtained. Results: There was significant improvement in the experimental group in all parameters, whereas the placebo group did not show any change with respect to their baseline parameters. There was significant improvement in the experimental group in all parameters, namely, VO2 max (t = 5.356; P < 0.001), METS (t = 4.483; P < 0.001), and time for exhaustion on treadmill (t = 4.813; P < 0.001) in comparison to the placebo group which did not show any change with respect to their baseline parameters. Conclusion: Ashwagandha improved the cardiorespiratory endurance of the elite athletes. PMID:23326093

  13. Effects of eight-week supplementation of Ashwagandha on cardiorespiratory endurance in elite Indian cyclists

    Directory of Open Access Journals (Sweden)

    Shweta Shenoy

    2012-01-01

    Full Text Available Background: Cycling is an endurance sport relying mainly on aerobic capacity to provide fuel during long-duration cycling events. Athletes are constantly searching for new methods to improve this capacity through various nutritional and ergogenic aids. Purpose: The aim of the study was to find out the effect of Ashwagandha on the cardiorespiratory endurance capacity, that is, aerobic capacity of elite Indian cyclists. Materials and Methods: Forty elite (elite here refers to the participation of the athlete in at least state-level events Indian cyclists were chosen randomly and were equally divided into experimental and placebo groups. The experimental group received 500 mg capsules of aqueous roots of Ashwagandha twice daily for eight weeks, whereas the placebo group received starch capsules. Outcome Measures: The baseline treadmill test for the cyclists were performed to measure their aerobic capacity in terms of maximal aerobic capacity (VO 2 max, metabolic equivalent, respiratory exchange ratio (RER, and total time for the athlete to reach his exhaustion stage. After eight weeks of supplementation, the treadmill test was again performed and results were obtained. Results: There was significant improvement in the experimental group in all parameters, whereas the placebo group did not show any change with respect to their baseline parameters. There was significant improvement in the experimental group in all parameters, namely, VO 2 max (t = 5.356; P < 0.001, METS (t = 4.483; P < 0.001, and time for exhaustion on treadmill (t = 4.813; P < 0.001 in comparison to the placebo group which did not show any change with respect to their baseline parameters. Conclusion: Ashwagandha improved the cardiorespiratory endurance of the elite athletes.

  14. Effects of 4:1 carbohydrate/protein solution versus a carbohydrate-alone solution on IL-6, TNF-α, and cortisol during prolonged cycling in hot environmental conditions

    Directory of Open Access Journals (Sweden)

    Cosio-Lima LM

    2012-03-01

    Full Text Available Ludmila M Cosio-Lima, Bhargav Desai, John W Stelzer, Petra B SchulerDepartment of Health, Leisure, and Exercise Science, University of West Florida, Pensacola, FL, USAPurpose: Intense or prolonged exercise and/or heat stress might affect the immune system creating a response similar to trauma or inflammation, resulting in an increase in the susceptibility to viral infections. For example, during prolonged exercise, inflammatory cytokines, such as tumor necrosis factor (TNF-α, interleukin (IL-6, and the stress hormone cortisol are produced and released. Although there have been several studies examining the effects of nutritional supplementation on cytokine release in elite athletes, few studies have investigated the effects of different energy drinks during exercise in adverse environmental conditions. Therefore, the purpose of this study was to compare plasma levels of inflammatory cytokines TNF-α and IL-6, and the stress hormone cortisol, during prolonged cycling under hot environmental conditions while ingesting fluid that contains a ratio of 4:1 carbohydrates and protein (4:1 CHO/PRO versus a carbohydrate-only drink (CHO.Methods: Six male cyclists (aged 27 ± 8 years; weight 75.5 ± 3.4 kg; VO2max = 66 ± 2.7 mL/kg/min, mean ± standard error rode on a stationary ergometer on two separate sessions for 2.5 hours at 75% VO2max in an environmental chamber set at 35°C and 60% relative humidity. During the first session the cyclists were given 4 mL/kg body weight of a 6% carbohydrate solution every 15 minutes. During the second session they were given 4 mL/kg body weight of a 4:1 carbohydrate/protein drink every 15 minutes. Subjects were not aware of which drink they were given in each trial. Blood samples were taken pre-, immediately post-, and 12 hours post-exercise. SPSS (IBM Corp, Armonk, NY was utilized to analyze data through repeated measures analysis of variance.Results: No significant main effect was observed between treatments in

  15. Annual cycle solar energy utilization with seasonal storage. Part 7. Examination on design and control of the system partially recovering exhaust heat of heat pump; Kisetsukan chikunetsu ni yoru nenkan cycle taiyo energy riyo system ni kansuru kenkyu. 7. Bubuntekina hainetsu kaishu wo koryoshita baai no sekkei seigyoho no kento

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, H.; Okumiya, M. [Nagoya University, Nagoya (Japan)

    1996-10-27

    The capacity and performance of the existing system that recovers the overall heating and cooling exhaust heat completely into a seasonal storage tank and the system that discharges the exhaust heat slightly to the outside and recovers it partially were compared and investigated. The system uses a central single-duct discharge system as an air-conditioning system. A heat pump and a flat-plate solar collector installed on the roof of a building are used as the heat source. The seasonal storage tank in the ground just under the building is a cylindrical water tank of 5 m deep with the concrete used as body. The upper surface of a storage tank is heat-insulated by a stylo-platform of 200 mm, and the lower side surface by a stylo-platform of 100 mm. Calculation when the difference in temperature used in a seasonal storage tank is set to 35{degree}C and 25{degree}C was performed for the system that has two control methods. The overall exhaust heat recovery system is almost the same in energy performance as the partial exhaust heat recovery system. The partial exhaust heat recovery system is more advantageous on the economic side. 4 refs., 6 figs., 3 tabs.

  16. Aircraft exhaust sulfur emissions

    Energy Technology Data Exchange (ETDEWEB)

    Brown, R.C.; Anderson, M.R.; Miake-Lye, R.C.; Kolb, C.E. [Aerodyne Research, Inc., Billerica, MA (United States). Center for Chemical and Environmental Physics; Sorokin, A.A.; Buriko, Y.I. [Scientific Research Center `Ecolen`, Moscow (Russian Federation)

    1997-12-31

    The extent to which fuel sulfur is converted to SO{sub 3} during combustion and the subsequent turbine flow in supersonic and subsonic aircraft engines is estimated numerically. The analysis is based on: a flamelet model with non-equilibrium sulfur chemistry for the combustor, and a one-dimensional, two-stream model with finite rate chemical kinetics for the turbine. The results indicate that between 2% and 10% of the fuel sulfur is emitted as SO{sub 3}. It is also shown that, for a high fuel sulfur mass loading, conversion in the turbine is limited by the level of atomic oxygen at the combustor exit, leading to higher SO{sub 2} oxidation efficiency at lower fuel sulfur loadings. While SO{sub 2} and SO{sub 3} are the primary oxidation products, the model results further indicate H{sub 2}SO{sub 4} levels on the order of 0.1 ppm for supersonic expansions through a divergent nozzle. This source of fully oxidized S(6) (SO{sub 3} + H{sub 2}SO{sub 4}) exceeds previously calculated S(6) levels due to oxidation of SO{sub 2} by OH in the exhaust plume outside the engine nozzle. (author) 26 refs.

  17. The Exhaustive Lexicalisation Principle

    Directory of Open Access Journals (Sweden)

    Antonio Fábregas

    2007-12-01

    Full Text Available In this article I revisit the well-known empirical problem of manner of motion verbs with directional complements in Spanish. I present some data that, to my mind, had not received due attention in previous studies and I show that some manner of motion verbs actually allow directionals with the preposition a, while all of them allow them with prepositions like hacia or hasta. I argue that this pattern is due to a principle that states that every syntactic feature must be identified by lexical insertion, the Exhaustive Lexicalisation Principle. The crucial problem with directional complements is that the Spanish preposition a is locative, in contrast with English to, and, therefore, unable to identify the Path feature. Some verbs license the directional with a because they can lexicalise Path altogether with the verb; all verbs can combine with hasta or hacia because these prepositions lexicalise Path. When neither the verb nor the preposition lexicalise the Path, the construction is ungrammatical.

  18. Economics of exhaustible resources

    Energy Technology Data Exchange (ETDEWEB)

    Rabhan, S.A.

    1986-01-01

    This dissertation deals with various issues of resource depletion, beginning with a rather comprehensive review of the literature. The resource scarcity is the first issue dealt with, where differentiation is made between Ricardian and Pure scarcities of exhaustible resources. While the Ricardian scarcity is properly acknowledged and modeled in the resource literature, the fact that the resource stocks are always decreasing with extraction (i.e., the pure scarcity) is overlooked. One important conclusion of the scarcity analysis is that the steady-state point defining the equilibrium values for the nonresource output to capital and the resource flow to resource stock ratios, is found to be a moving one, as a result of the increasing scarcity mechanism. Another observation about the literature is that there is a marked bias in favor of long run, developed economies' problems and resource inputs as opposed to the problems of developing economies and resource exports. Thus, a theoretical framework is developed where not only resource inputs and exports are analyzed but resource exports are advanced as a vehicle for development. Within the context of this theoretical framework, it is concluded that optimality dictates that the resource inputs and exports, expressed per unit of the capital stock, be declining over time. Furthermore, the resource exports are proposed as the domestic substitute for foreign aid.

  19. Iron Metabolism in Field Hockey Players During an Annual Training Cycle

    Directory of Open Access Journals (Sweden)

    Podgórski Tomasz

    2015-09-01

    Full Text Available Post-physical training changes in iron metabolism in the human body often occur. To fully describe these processes, fifteen male Polish National Team field hockey players (age 27.7 ± 5.2 years, body mass 72.8 ± 7.6 kg and body height 177.1 ± 5.7 cm were examined in three phases of an annual training cycle: preparatory (T1, competitive (T2 and transition (T3. To assess aerobic fitness, maximal oxygen uptake (VO2max was evaluated. Based on the iron concentration, the changes in total iron binding capacity (TIBC, unsaturated iron binding capacity (UIBC and other selected haematological indicators (haemoglobin, erythrocytes, mean corpuscular haemoglobin - MCH in iron metabolism were estimated. The average values of maximum oxygen uptake increased from 54.97 ± 3.62 ml·kg−1·min−1 in T1 to 59.93 ± 3.55 ml·kg−1·min−1 in T2 (p<0.05 and then decreased to 56.21 ± 4.56 ml·kg−1·min−1 in T3 (p<0.05. No statistically significant changes in the erythrocyte count were noted. The MCH and haemoglobin concentration decreased between T1 and T2. The maximal exercise test caused a significant (p<0.05 increase in the plasma iron concentration during the competition and transition phases. Progressive but non-significant increases in resting iron concentration, TIBC and UIBC in the analysed annual training cycle were noted. To show global changes in iron metabolism in the human body, it is necessary to determine additional variables, i.e. UIBC, TIBC, haemoglobin, MCH or the erythrocyte count. The direction of changes in iron metabolism depends on both the duration and intensity of the physical activity and the fitness level of the subjects. Dietary intake of iron increases the level of this trace element and prevents anaemia associated with training overloads.

  20. On factor analysis about the increment of %△ Vo2 max after endurance training%耐力训练后最大摄氧量增量(%△(V)o2max)的因素分析

    Institute of Scientific and Technical Information of China (English)

    卢塞军

    2002-01-01

    根据有关文献资料的统计结果,进一步分析各负荷因素对(V)o2max的影响,揭示(V)o2max增量规律,掌握改善(V)o2max的训练方法和运动处方,为发展耐力素质和科学健身提供研究资料和科学依据.

  1. AEROBIC FITNESS LEVEL TYPICAL OF ELITE ATHLETES IS NOT ASSOCIATED WITH EVEN FASTER VO2 KINETICS DURING CYCLING EXERCISE

    Directory of Open Access Journals (Sweden)

    Tiago R. Figueira

    2008-03-01

    Full Text Available The aim of this study was to address the question if the VO2 kinetics is further improved as the aerobic training status increases from trained to elite level athletes. Maximal oxygen uptake (VO2max, work-rate associated to VO2max (IVO2max and VO2 kinetics of moderate (Mod and maximal exercise (Max were determined in fifty- five subjects. Then, they were assigned into three groups: low (LF, intermediate (IF and high (HF aerobic fitness level. In average, the VO2max of LF, IF and HF groups were, respectively, 36.0 ± 3.1, 51.1 ± 4.5 and 68.1 ± 3.9 ml·kg·min-1 (p < 0.05 among each other. VO2 kinetics mean response time of both exercise intensities were significantly faster (p < 0.05 in HF (Mod, 27.5 ± 5.5 s; Max, 32.6 ± 8.3 s and IF (Mod, 25.0 ± 3.1 s; Max, 42.6 ± 10.4 s when compared to LF (Mod, 35.7 ± 7.9 s; Max: 57.8 ± 17.8 s. We can conclude that VO2 kinetics is improved as the fitness level is increased from low to intermediate but not further improved as the aerobic fitness level increases from intermediate to high.

  2. Exhaust gas energy recovery system of pneumatic driving automotive engine

    Institute of Scientific and Technical Information of China (English)

    Han Yongqiang; Sun Wenxu; Li Qinghua; Zhong Ming; Hao Wei; Du Wenchang

    2011-01-01

    Almost the same quantity to net output work of energy has been carried out and wasted by exhaust gas in typical automotive engine. Recovering the energy from exhaust gas and converting to mechanical energy will dramatically increase the heat efficiency and decrease the fuel consumption. With the increasing demand of fuel conservation, exhaust gas energy recovery technologies have been a hot topic. At present, many researches have been focused on heating or cooling the cab, mechanical energy using and thermo-electronic converting. Unfortunately, the complicated transmission of mechanical energy using and the depressed efficiency of thermo-electronic converting restrict their widely applying. In this paper, a kind of exhaust gas energy recovery system of pneumatic driving automotive engine, in which highly compressed air acts as energy storing and converting carrier, has been established. Pneumatic driving motor can produce moderate speed and high torque output, which is compatible for engine using. The feasibility has been certificated by GT-Power simulation and laboratory testes. The technologies about increasing recovery efficiency have been discussed in detail. The results demonstrated that the in parallel exhaust gas energy recovery system, which is similar to the compound turbo-charger structure can recovery 8 to 10 percent of rated power output. At last, a comprehensive system,which includes Rankine cycle based power wheel cycle unit etc. , has been introduced.

  3. Cardiorespiratory Effects of One-Legged High-Intensity Interval Training in Normoxia and Hypoxia: A Pilot Study.

    Science.gov (United States)

    Menz, Verena; Semsch, Mona; Mosbach, Florian; Burtscher, Martin

    2016-06-01

    A higher-than-average maximal oxygen consumption (VO2max), is closely associated with decreased morbidity and mortality and improved quality of life and acts as a marker of cardiorespiratory fitness. Although there is no consensus about an optimal training method to enhance VO2max, nevertheless training of small muscle groups and repeated exposure to hypoxia seem to be promising approaches. Therefore, this study was aimed at gaining innovative insights into the effects of small muscle group training in normoxia and hypoxia. Thirteen healthy participants were randomly assigned to the hypoxic (HG, n = 7) or normoxic (NG, n = 6) training group. Both groups completed nine high-intensity interval training sessions in 3 wks. The NG performed the training in normoxia (FiO2: 0.21; ~ 600 m) and the HG in hypoxia (FiO2: 0.126; ~ 4500 m). Each session consisted of 4 x 4 min one-legged cycling at 90% of maximal heart rate separated by 4 min recovery periods. Before and after the intervention period, VO2max and peak power output (Wmax) and responses to submaximal cycling (100 and 150 watts) were assessed in a laboratory cycling test. Peak power output significantly improved within both groups (9.6 ± 4.8% and 12.6 ± 8.9% for HG and NG, respectively) with no significant interaction (p = 0.277). However, VO2max only significantly increased after training in hypoxia from 45.4 ± 10.1 to 50.0 ± 9.8 ml/min/kg (10.8 ± 6.0%; p = 0.002) with no significant interaction (p = 0.146). The maximal O2-pulse improved within the HG and demonstrated a significant interaction (p = 0.040). One-legged cycling training significantly improved VO2max and peak power output. Training under hypoxic conditions may generate greater effects on VO2max than a similar training in normoxia and is considered as a promising training method for improving cardiorespiratory fitness. Key pointsNine sessions of one-legged high-intensity interval training significantly improved physical fitness.One-legged hypoxic

  4. Splanchnic blood flow and hepatic glucose production in exercising humans

    DEFF Research Database (Denmark)

    Bergeron, R; Kjaer, M; Simonsen, L

    2001-01-01

    The study examined the implication of the renin-angiotensin system (RAS) in regulation of splanchnic blood flow and glucose production in exercising humans. Subjects cycled for 40 min at 50% maximal O(2) consumption (VO(2 max)) followed by 30 min at 70% VO(2 max) either with [angiotensin......-blockade group vs. the control group, hormones, metabolites, VO(2), and RER followed the same pattern of changes in ACE-blockade and control groups during exercise. Splanchnic blood flow (at rest: 1.67 +/- 0.12, ACE blockade; 1.59 +/- 0.18 l/min, control) decreased during moderate exercise (0.78 +/- 0.07, ACE...

  5. Combined effects of exercise and restriction of energy intake on moderately obese women.

    OpenAIRE

    Thomas, D P; Belko, A Z; Mulroy, G L; Haas, J. D.; Roe, D A

    1986-01-01

    The current study was designed to assess the contribution of dietary-induced weight reduction on improvements in functional capacity in moderate obesity. Twelve females (means age = 29 yr, means fat percentage = 37%) served as subjects for the study. Subjects trained on a cycle ergometer 30 min.day-1, six day.wk-1 for three or six weeks at 75 to 85 per cent of maximum heart rate (HR max). Improvements in maximal oxygen uptake (delta VO2 max I.min-1) and functional capacity (delta VO2 max ml.k...

  6. Comparison of nine theoretical models for estimating the mechanical power output in cycling

    Science.gov (United States)

    González‐Haro, Carlos; Ballarini, P A Galilea; Soria, M; Drobnic, F; Escanero, J F

    2007-01-01

    Objective To assess which of the equations used to estimate mechanical power output for a wide aerobic range of exercise intensities gives the closest value to that measured with the SRM training system. Methods Thirty four triathletes and endurance cyclists of both sexes (mean (SD) age 24 (5) years, height 176.3 (6.6) cm, weight 69.4 (7.6) kg and Vo2max 61.5 (5.9) ml/kg/min) performed three incremental tests, one in the laboratory and two in the velodrome. The mean mechanical power output measured with the SRM training system in the velodrome tests corresponding to each stage of the tests was compared with the values theoretically estimated using the nine most referenced equations in literature (Whitt (Ergonomics 1971;14:419–24); Di Prampero et al (J Appl Physiol 1979;47:201–6); Whitt and Wilson (Bicycling science. Cambridge: MIT Press, 1982); Kyle (Racing with the sun. Philadelphia: Society of Automotive Engineers, 1991:43–50); Menard (First International Congress on Science and Cycling Skills, Malaga, 1992); Olds et al (J Appl Physiol 1995;78:1596–611; J Appl Physiol 1993;75:730–7); Broker (USOC Sport Science and Technology Report 1–24, 1994); Candau et al (Med Sci Sports Exerc 1999;31:1441–7)). This comparison was made using the mean squared error of prediction, the systematic error and the random error. Results The equations of Candau et al, Di Prampero et al, Olds et al (J Appl Physiol 1993;75:730–7) and Whitt gave a moderate mean squared error of prediction (12.7%, 21.6%, 13.2% and 16.5%, respectively) and a low random error (0.5%, 0.6%, 0.7% and 0.8%, respectively). Conclusions The equations of Candau et al and Di Prampero et al give the best estimate of mechanical power output when compared with measurements obtained with the SRM training system. PMID:17341588

  7. 14 CFR 29.1123 - Exhaust piping.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Exhaust piping. 29.1123 Section 29.1123... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Exhaust System § 29.1123 Exhaust piping. (a) Exhaust piping must be heat and corrosion resistant, and must have provisions to prevent failure due to...

  8. 14 CFR 25.1123 - Exhaust piping.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Exhaust piping. 25.1123 Section 25.1123... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Exhaust System § 25.1123 Exhaust piping. For powerplant and auxiliary power unit installations, the following apply: (a) Exhaust piping must be heat...

  9. 46 CFR 169.609 - Exhaust systems.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Exhaust systems. 169.609 Section 169.609 Shipping COAST... Electrical Internal Combustion Engine Installations § 169.609 Exhaust systems. Engine exhaust installations... Yacht Council, Inc. Standard P-1, “Safe Installation of Exhaust Systems for Propulsion and Auxiliary...

  10. 49 CFR 325.91 - Exhaust systems.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Exhaust systems. 325.91 Section 325.91... EMISSION STANDARDS Exhaust Systems and Tires § 325.91 Exhaust systems. Link to an amendment published at 75 FR 57193, Sept. 20, 2010. A motor vehicle does not conform to the visual exhaust system inspection...

  11. Influence of repeated bouts of eccentric exercise on high-intensity aerobic performance.

    Science.gov (United States)

    Higino, Wonder Passoni; Aparecido de Souza, Renato; Cavalcanti, Fabio de Sousa; Cardoso, Anderlei Dos Santos; Vasconcelos, Murilo Victor; Fernandes da Silva, Fabiano; Leme, José Alexandre C A

    2016-08-01

    [Purpose] It is believed that eccentric high-intensity exercise can decrease performance in subsequent exercise. However, with repetition, the deleterious effects can be minimized. Thus, this study evaluated the influence of repeated bouts of eccentric exercise on subsequent high-intensity aerobic performance. [Subjects and Methods] Seven healthy and sedentary male volunteers were r