Heart rate and performance parameters in elite cyclists: a longitudinal study

PURPOSE: This study was designed to evaluate the stability of target heart rate (HR) values corresponding to performance markers such as lactate threshold (LT) and the first and second ventilatory thresholds (VT1, VT2) in a group of 13 professional road cyclists (VO2max, approximately 75.0 mL x kg(-1) x min(-1)) during the course of a complete sports season. METHODS: Each subject performed a progressive exercise test on a bicycle ergometer (ramp protocol with workload increases of 25 W x min(-1)) three times during the season corresponding to the "active" rest (fall: November), precompetition (winter: January), and competition periods (spring: May) to determine HR values at LT, VT1 and VT2. RESULTS: Despite a significant improvement in performance throughout the training season (i.e., increases in the power output eliciting LT, VT1, or VT2), target HR values were overall stable (HR at LT: 154 +/- 3, 152 +/- 3, and 154 +/- 2 beats x min(-1); HR at VT1: 155 +/- 3, 156 +/- 3, and 159 +/- 3 beats x min(-1); and at VT2: 178 +/- 2, 173 +/- 3, and 176 +/- 2 beats x min(-1) during rest, precompetition, and competition periods, respectively). CONCLUSION: A single laboratory testing session at the beginning of the season might be sufficient to adequately prescribe training loads based on HR data in elite endurance athletes such as professional cyclists. This would simplify the testing schedule generally used for this type of athlete.     

Ventilatory threshold and maximal oxygen uptake during cycling and running in female triathletes

Maximal oxygen uptake (VO2max) and the ventilatory threshold (Tvent) were measured during cycle ergometry (CE) and treadmill running (TR) in a group of 10 highly trained female triathletes. Tvent was defined as the VO2 at which the ventilatory equivalent for oxygen increased without a marked rise in the ventilatory equivalent for carbon dioxide. Female triathletes achieved a significantly higher mean (+/- SE) relative VO2max for running (63.6 +/- 1.2 ml.kg-1.min-1) than for cycling (59.9 +/- 1.3 ml.kg-1.min-1). When oxygen uptake measured at the ventilatory threshold was expressed as a percent of VO2max, the mean value obtained for TR (74.0 +/- 2.0% of VO2max) was significantly greater than the value obtained for CE (62.7 +/- 2.1% of VO2max). This occurred even though the total training time and intensity were similar for the two modes of exercise. Female triathletes had average running and cycling VO2max values that compared favorably with maximal oxygen uptake values previously reported for elite female runners and cyclists, respectively. However, mean running and cycling Tvent values (VO2 Tvent as%VO2max) were lower than recently reported values for single-sport athletes. The physiological variability between the triathletes studied and single-sport athletes may be attributed in part to differences in training distance or intensity, and/or to variations in the number of years of intense training in a specific mode of exercise. It was concluded that these triathletes were well-trained in both running and cycling, but not to the same extent as female athletes who only train and compete in running or cycling.     

划船运动员最大摄氧量和无氧阈的测定与分析

作者对25名男子划船运动员进行了最大有氧代谢能力和无氧阈的测定,发现上述指标均低于国外同项运动员及国内其他耐力运动员,作者认为主要原因是训练量与强度不足,并从选材与训练安排上提出了改进意见。     

Autonomic recovery after exercise in trained athletes: intensity and duration effects

PURPOSE: To investigate the effects of training intensity and duration, through a range representative of training in endurance athletes, on acute recovery of autonomic nervous system (ANS) balance after exercise. METHODS: Nine highly trained (HT) male runners (VO2max 72 +/- 5 mL.kg.min(-1), 14 +/- 3 training hours per week) and eight trained (T) male subjects (VO2max 60 +/- 5 mL.kg.min(-1), 7 +/- 1 training hours per week) completed preliminary testing to determine ventilatory thresholds (VT1, VT2) and VO2max. HT performed four intensity-controlled training sessions: 60 min and 120 min below VT1; 60 min with 30 min between VT1 and VT2 (threshold); and 60 min above VT2 (6 x 3 min at 96% VO2max, 2 min of recovery). T also completed the interval session to compare ANS recovery between HT and T. Supine heart rate variability (HRV) was quantified at regular intervals through 4 h of recovery. RESULTS: When HT ran 60 or 120 min below VT1, HRV returned to pretraining values within 5-10 min. However, training at threshold (2.7 +/- 0.4 mM) or above VT2 (7.1 +/- 0.7 mM) induced a significant, but essentially identical, delay of HRV recovery (return to baseline by approximately 30 min). In T, HRV recovery was significantly slower, with HRV returning to baseline by >or=90 min after the same interval session. CONCLUSIONS: In the highly trained endurance athlete, exercise for 相似文献   

Measuring and predicting maximal aerobic power in international-level intermittent sport athletes

AIM: The purpose of this study was to measure actual VO2max during the multi-stage fitness test (MSFT) and to compare this with predicted values obtained using previously established, commonly used methods. We also wanted to determine a new and more accurate regression equation for the prediction of VO2max in intermittent sport athletes. METHODS: Twenty-six, elite, male, intermittent sport athletes performed the MSFT with oxygen uptake (VO2) and heart rate (HR) measured throughout. Paired t-tests were used to compare measured VO2max with predicted VO2max. Linear regression was used to determine the equation for the prediction of VO2max from the total number of shuttles completed. RESULTS: There were no differences between the two methods of predicting VO2max, however, both predicted values (53.6+/-3.9 and 51.3+/-4 mL x kg(-1) x min(-1)) were significantly lower (9.3% and 13.2%, respectively) than measured VO2max (59.1+/-6.6 mL x kg(-1) x min(-1), P < 0.001). Correlations between measured and predicted VO2max were similar for both prediction methods (r = 0.61, P = 0.013 and r = 0.68 and P = 0.004). We present a new prediction equation [Y (VO2max, mL x kg(-1) x min(-1)) = 0.38 x total number of shuttles completed +25.98] (where R = 0.69; R2 = 0.48; SEE = 4.9 mL x kg(-1) x min(-1); SEE% = 8.3) which provides a more valid method of predicting actual max in intermittent sport athletes. CONCLUSIONS: A new regression equation to predict VO2max in intermittent sport athletes has been established. Whilst some error in predicting VO2max still exists, the new equation will provide coaches and sport-scientists with a more suitable equation with which to predict VO2max in intermittent sport athletes.     

Heart rate and blood pressure variability during heavy training and overtraining in the female athlete

We investigated heavy training- and overtraining-induced changes in heart rate and blood pressure variability during supine rest and in response to head-up tilt in female endurance athletes. Nine young female experimental athletes (ETG) increased their training volume at the intensity of 70-90% of maximal oxygen uptake (VO2max) by 125% and training volume at the intensity of < 70% of VO2max by 100% during 6-9 weeks. The corresponding increases in 6 female control athletes were 5% and 10%. The VO2max of the ETG and the control athletes did not change, but it decreased from 53.0 +/- 2.2 ml x kg(-1) x min(-1) to 50.2 +/- 2.3 ml x kg(-1) x min(-1) (mean+/-SEM, p < 0.01) in five overtrained experimental athletes. In the ETG, low-frequency power of R-R interval (RRI) variability during supine rest increased from 6 +/- 1 ms2 x 10(2) to 9 +/- 2 ms2 x 10(2) (p < 0.05). The 30/15 index (= RRI(max 30)/RRI(min 15), where RRI(max 30) denotes the longest RRI close to the 30th RRI and RRI(min 15) denotes the shortest RRI close to the 15th RRI after assuming upright position in the head-up tilt test), decreased as a result of training (analysis of variance, p = 0.05). In the ETG, changes in VO2max were related to the changes in total power of RRI variability during standing (r = 0.74, p < 0.05). Heart rate response to prolonged standing after head-up tilt was either accentuated or attenuated in the overtrained athletes as compared to the normal training state. We conclude that heavy training could increase cardiac sympathetic modulation during supine rest and attenuated biphasic baroreflex-mediated response appearing just after shifting to an upright position. Heavy-training-/overtraining-induced decrease in maximal aerobic power was related to decreased heart rate variability during standing. Physiological responses to overtraining were individual.     

Erythropoiesis and performance after two weeks of living high and training low in well trained triathletes

The purpose of our study was to evaluate hematologic acclimatization during 2 weeks of intensive normoxic training with regeneration at moderate altitude (living high-training low, LHTL) and its effects on sea-level performance in well trained athletes compared to another group of equally trained athletes under control conditions (living low - training low, CONTROL). Twenty-one triathletes were ascribed either to LHTL (n = 11; age: 23.0 +/- 4.3 yrs; VO 2 max: 62.5 +/- 9.7 [ml x min -1 x kg -1]) living at 1956 m of altitude or to CONTROL (n = 10; age: 18.7 +/- 5.6 yrs; VO 2 max: 60.5 +/- 6.7 ml x min -1 x kg -1) living at 800 m. Both groups performed an equal training schedule at 800 m. VO 2 max, endurance performance, erythropoietin in serum, hemoglobin mass (Hb tot, CO-rebreathing method) and hematological quantities were measured. A tendency to improved performance in LHTL after the camp was not significant (p < 0.07). Erythropoietin concentration increased temporarily in LHTL (Delta 14.3 +/- 8.7 mU x ml -1; p < 0.012). Hb tot remained unchanged in LHTL whereas was slightly decreased from 12.5 +/- 1.3 to 11.9 +/- 1.3g x kg -1 in CONTROL (p < 0.01). As the reticulocyte number tended to higher values in LHTL than in CONTROL, it seems that a moderate stimulation of erythropoiesis during regeneration at altitude served as a compensation for an exercise-induced destruction of red cells.     

Evidence for an inadequate hyperventilation inducing arterial hypoxemia at submaximal exercise in all highly trained endurance athletes

PURPOSE: The majority of highly trained endurance athletes with a maximal oxygen uptake greater than 60 mL x min(-1) x kg(-1) develop exercise-induced hypoxemia (EIH). Yet some of them apparently do not. The pathophysiology of EIH seems to be multifactorial, and one explanatory hypothesis is a relative hypoventilation. Nevertheless, conflicting results have been reported concerning its contribution to EIH. The aim of this study was to compare the cardiorespiratory responses to maximal exercise of highly trained endurance athletes demonstrating the same aerobic capacity without EIH (N athletes) and with EIH (H athletes). METHODS: Ten N athletes and twelve H athletes performed an incremental exercise test. Measurements of arterial blood gases and cardiorespiratory parameters were performed at rest and during exercise. RESULTS: All athletes presented a significant decrease in PaO2 (P < 0.05) from rest up to 80% VO2max associated with an increase in PaCO2, both findings consistent with a relative hypoventilation. Then the H athletes, who had a greater training volume per week and a higher second ventilatory threshold than the N athletes (respectively, 17 +/- 1.1 vs 13.1 +/- 0.7 h x wk(-1); 91.8 +/- 1.7 vs 86.1 +/- 1.8% VO2max), presented a continuous PaO2 decrease up to VO2max. This was associated with a widening (Ai-a)DO2. CONCLUSION: This study showed that a relative hypoventilation, probably induced by a high level of endurance training, induced hypoxemia in all athletes. However, a nonventilatory mechanism, perhaps related to the volume of training, seemed to affect gas exchanges beyond the second ventilatory threshold in the H athletes, thereby enhancing EIH.     

Maximal oxygen uptake and power of lower limbs during a competitive season in triathletes

BACKGROUND: In order to study the effect of a competitive triathlon season on maximal oxygen uptake (VO2max), aerobic power (AeP) and anaerobic performance (AnP) of the lower limbs, eight triathletes performed exercise tests after: (1) a pre-competition period (Pre-COMP) (2) a competitive period (COMP), and (3) a low (volume and intensity) training period (Post-COMP). The tests were a vertical jump-and-reach test and an incremental exercise test on a cycle ergometer. Ventilatory data were collected every minute during the incremental test with an automated breath-by-breath system and the heart-rate was monitored using a telemetric system. RESULTS: No changes in VO2max were observed, whereas AeP decreased after Post-COMP compared to Pre-COMP and COMP and AnP decreased during COMP compared to Pre-COMP and Post-COMP. In addition, second ventilatory threshold (VT2) and power output at first ventilatory threshold (VT1) and VT2 decreased after Post-COMP. CONCLUSION: This study showed that six weeks of low volume and intensity of training is too long a period to preserve adaptations to training, although a stable maximal oxygen uptake throughout the triathlon season was observed. Moreover, the AnP decrease during COMP was probably in relation with the repetitive nature of the training mode and/or triathlon competitions.     

Montelukast does not affect exercise performance at subfreezing temperature in highly trained non-asthmatic endurance athletes

Anti-leukotriene therapy represents a new principle in asthma treatment. As elite athletes can have asthma, this double-blind, placebo-controlled, randomised cross-over study investigated the effect of 10 mg oral montelukast, a specific and potent cysteinyl leukotriene receptor antagonist, on physiological responses to submaximal and maximal aerobic exercise at -15 degrees C in 14 non-asthmatic highly trained endurance male athletes (maximal oxygen uptake [VO2 max] > 70 ml x kg(-1) x min(-1)). Heart rate, capillary blood lactate, minute ventilation with tidal volume and breathing frequency, respiratory exchange ratio and oxygen uptake were measured during the warm-up run of 10 min at 50%, runs of 10 min at 90% and 5 min at 80% VO2max, and a timed run to exhaustion. Spirometry was performed at baseline, at four hours after tablet ingestion, after warm-up and exercise at 80% VO2max, and in the post exercise period. Compared to placebo, montelukast did not increase baseline FEV1, have a beneficial effect on physiological performance variables, or increase the mean (SD) running time to exhaustion (montelukast: 332.3 [45.8] s, placebo: 340.1 [53.3] s, P = 0.22). These findings do not suggest the need for disallowing the use of this drug by asthmatic athletes.     

Inspiratory muscle training fails to improve endurance capacity in athletes

PURPOSE: The purpose of this study was to examine the effects of specific inspiratory muscle training (IMT) on respiratory muscle strength and endurance and whole-body endurance exercise capacity in competitive endurance athletes. METHODS: Seven collegiate distance runners (5 male/2 female; VO2max = 59.9 +/- 11.7 mL.kg-1.min-1) were recruited to participate in this study. Initial testing included maximal oxygen consumption (VO2max), sustained maximal inspiratory mouth pressure (MIP), breathing endurance time (BET) at 60% MIP, and endurance run time (ERT) at 85% VO2max. Heart rate (HR), minute ventilation (VE), oxygen consumption (VO2), and ratings of perceived dyspnea (RPD) were recorded at 5-min intervals and during the last minute of the endurance run. Blood lactate concentration (BLC) was also obtained immediately before and at 2 min after the endurance run. All testing was repeated after 4 wk of IMT (50-65% MIP, approximately 25 min x d(-1), 4-5 sessions/week, 4 wk). RESULTS: After 4 wk of IMT, MIP and BET were significantly increased compared with pretraining values (P < 0.05). No significant differences between pre and post values were observed in VO2max or ERT at 85% VO2max after IMT. No significant differences between pre and post values were detected in HR, VE, VO2, or RPD during the endurance run as measured at steady state and end of the test after IMT. BLC was not significantly different before or at 2 min after the endurance run between pre and post IMT. CONCLUSION: These results suggest that IMT significantly improves respiratory muscle strength and endurance. However, these improvements in respiratory muscle function are not transferable to VO2max or endurance exercise capacity as assessed at 85% VO2max in competitive athletes.     

Comparison of muscle oxygen consumption measured by near infrared continuous wave spectroscopy during supramaximal and intermittent pedalling exercise

The two purposes of the present study were 1) to determine the oxygen consumption in working skeletal muscle from the oxygenation measured by near-infrared continuous-wave spectroscopy (NIRcws) with the arterial occlusion method during the resting condition, INT(VT), and INT(MAX) and 2) to examine whether the decline rate of oxygenation is related to maximal oxygen uptake. Eight healthy males (aged 19.8 +/- 0.4 yr, height 166.9 +/- 17.4 cm, weight 62.1 +/- 2.5 kg, and maximal oxygen uptake [VO2max] 55.9 +/- 1.9 ml/kg x min(-1)) took part in this study. The oxygenation was measured by NIRcws during the Wingate anaerobic test (WAnT) and two intermittent pedalling exercises of VT (INT(VT)) and maximal (INT(MAX)) work intensity. The decline rates of oxygenation obtained during the resting condition, INT(VT), and INT(MAX) with arterial occlusion were 0.43 +/- 0.05%/sec, 4.94 +/- 0.31%/sec, and 8.16 +/- 0.38%/sec, respectively, and that during the WAnT without arterial occlusion was 8.73 +/- 0.49%/sec. The decline rate of oxygenation during the WAnTwas significantly (p < 0.0001) related to maximal oxygen uptake (VO2max). These findings indicate that O2 is utilized from the early phase, even during a supramaximal pedalling exercise, and that the oxidative metabolic capacity may be a factor contributing to supramaximal exercises. Therefore the arterial occlusion method with NIRcws is suitable for the evaluation of the muscle O2 consumption during exercise noninvasively.     

Maximal oxygen uptake and lactate metabolism are normal in chronic fatigue syndrome.

PURPOSE: Previous studies in chronic fatigue syndrome (CFS) have reported reductions in maximal oxygen uptake (VO(2max)), yet often the testing procedures have not followed accepted guidelines, and gender data have been pooled. The present study was undertaken to reevaluate exercise capacity in CFS patients by using "gold standard" maximal exercise testing methodology and stratifying results on a gender basis. METHODS: Sixteen male and 17 female CFS patients and their gender-, age-, and mass-matched sedentary controls performed incremental exercise to volitional exhaustion on a stationary cycle ergometer while selected cardiorespiratory and metabolic variables were measured. RESULTS: VO(2max) in male CFS patients was not different from control values (CFS: 40.5 +/- 6.7; controls: 43.3 +/- 8.6; mL x kg(-1) x min(-1)) and was 96.3 +/- 17.9% of the age-predicted value, indicating no functional aerobic impairment (3.7 +/- 17.9%). In female CFS patients, VO(2max) was lower than control values (CFS: 30.0 +/- 4.7; controls: 34.2 +/- 5.6; mL x kg(-1) x min(-1), P = 0.002), but controls were higher than the age-predicted value (112.6 +/- 15.4%, P = 0.008) whereas the CFS patients were 101.2 +/- 20.4%, indicating no functional aerobic impairment (-1.2 +/- 20.4%). Maximal heart rate (HR(max)) in male CFS patients was lower than their matched controls (CFS: 184 +/- 10; controls: 192 +/- 12; beats x min(-1); P = 0.016) but was 99.1 +/- 5.5% of their age-predicted value. In female CFS patients, HR(max) was not different from controls (CFS: 183 +/- 11; controls: 186 +/- 10; beats x min(-1)) and was 98.9 +/- 5.1% of the age-predicted value. The VO(2) at the lactate threshold (LT) in each gender group, whether expressed in mL x kg(-1) x min(-1) or as a percentage of VO(2max), was not different between CFS patients and controls. CONCLUSIONS: In contrast to most previous reports, the present study found that VO(2max), HR(max), and the LT in CFS patients of both genders were not different from the values expected in healthy sedentary individuals of a similar age.     

Measurement of maximal oxygen uptake from two different laboratory protocols in runners and squash players.

PURPOSE: The aims of the study were to assess whether different test protocols used to elicit maximal oxygen uptake values (VO2max) attain similar results, whether different VO2max protocols were preferable for different athletic groups, and to assess whether the noninvasive criteria used to indicate the attainment of VO2max are achieved similarly in different VO2max testing protocols. METHODS: This study evaluated the attainment of either VO2max or peak VO2 (VO2peak) during two treadmill VO2max protocols: a progressive speed protocol (PSP) and a progressive incline protocol (PIP). Ten runners and 10 squash players were studied to assess whether achievement of VO2max criteria was either sport-specific or protocol-specific, or both. RESULTS: There were no significant differences in the VO2peak values reached in either PSP or PIP protocol (64.4 +/- 5.9 vs 66.5 +/- 6.0 mLO2 x kg(-1) x min(-1)). But HRmax (196 +/- 5 vs 189 +/- 5 beats x min(-1); PSP vs PIP; P < 0.01) and RER (1.14 +/- 0.05 vs 1.07 +/- 0.04; PSP vs PIP; P < 0.01) were significantly higher during the PSP test. Fifty percent of the subjects reached a plateau in either test, and of these subjects, 90% satisfied the three noninvasive criteria for VO2max in the PSP group, compared with 10% in the PIP group. CONCLUSIONS: The indirect criteria used to assess the attainment of VO2max may be limited, as the VO2peak values were higher in the PIP protocol compared with the PSP protocol, although not significantly different, whereas the HR and RER values were significantly lower in the PIP than PSP protocol. Furthermore, only 50% of subjects demonstrated the plateau phenomenon in oxygen uptake with either protocol. It may be concluded that the measured physiological variables coinciding with VO2peak may differ when different protocols are used to elicit VO2max.     

Physiological responses to high-speed,open-wheel racecar driving

High-speed auto racing has been demonstrated to produce accelerated heart rate (HR) during competition. However, it has not been determined whether the increase in HR was due to physical work efforts or a result of emotional stress. PURPOSE: The purpose of this investigation was to examine the physiological responses associated with open-wheel automobile driving at competitive speeds. METHODS: Oxygen consumption and HR were assessed in seven professional automobile racing drivers during two incrementally paced driving sessions. A portable metabolic analyzer and EKG were directly attached to the subjects as they participated in driving tests on an oval speedway and a roadway course. Maximal physiological responses of the subjects were also determined during a graded treadmill test. RESULTS: During treadmill testing, maximal oxygen consumption (VO2max) ranged from of 42.0 to 59.7 mL x kg(-1) x min(-1) (mean +/- SD = 47.6+/-8.1). The road course and oval speedway testing at competitive speeds elicited mean VO2 values of 38.5 and 21.9 mL x kg(-1) x min(-1), respectively, which correspond to 79% and 45% of VO2max. Road course driving produced mean HR values of 152 beats x min(-1) with 142 beats x min(-1) recorded when driving at competitive speed on the speedway course. CONCLUSIONS: Professional open-wheel race drivers possess cardiorespiratory capacity similar to athletes participating in sports such as basketball, football, and baseball. The VO2 and HR responses to road course driving were similar to those previously reported in traditional sports settings. The findings of this study suggest that professional open-wheel racing drivers should be regarded as athletes that encounter significant physiological stresses.(2)     

Evolution of physiological and haematological parameters with training load in elite male road cyclists: a longitudinal study

AIM: The aim of this study was to describe and evaluate physiological parameters as a control tool for the monitoring of training in a group of elite cyclists during one season of training. METHODS: The study is divided into two periods (winter or 'volume' mesocycle and spring or 'intensity' mesocycle) between the tests that they carried out in the laboratory, consisting of a ramp test to exhaustion (work load increases 25 W X min(-1)) and a maximal lactate steady state (MLSS) test on a cycle ergometer. Macronutrients and hematological variables were recorded during the test periods as were the volume and the intensity of training sessions during the whole period of the study. RESULTS: The physiological data were similar to those previously reported for professional cyclists (approximately 450 Watts, approximately 78 mL x kg(-1) x min(-1)) and the values for the MLSS also agree with previous studies (approximately 250 Watts). Subjects improved the first ventilatory threshold (VT(1)) (approximately 52% to approximately 60% VO(2max)) and the second ventilatory threshold (VT(2)) (approximately 82% to approximately 87% VO(2max)) after the first period of training even though its low intensity focused on the performance of VT(1) (77% training in 'zone 1', under VT(1)). The MLSS improved after the first period (approximately 225 to approximately 250 Watts) and remained high in the second (approximately 255 Watts). High levels of creatine kinase (approximately 230 U x L(-1)) and urea (37 mg x L(-1)) were found, also a decrease in hemoglobin values (approximately 15.4 to approximately 14.7g x dL(-1)). CONCLUSION: The high level reached by the subjects after the first period of training suggests that two effort tests could be enough to plan training. On the other hand, the decrease in some red blood cell and nutrition parameters suggests that there should be greater control over them during the season.     

Physiological profile of very young soccer players

BACKGROUND: There is still much uncertainty and debate surrounding the physiological requirements of competitive soccer. The coaching emphasis on skill development, deficiencies in fitness training, conservative training methods lead to difficulty in the scientific study of soccer. METHODS: The physiological profiles of 22 young soccer players (mean age = 8.0+/-0.3 years, body mass = 28.2+/-3.2 kg, body height = 132.4+/-4.3 cm and body fat = 19.4+/-1.6 percent) were measured by the incremental exercise protocol on the treadmill with 5 percent inclination. All boys systematically trained at least 2 years with a minimum of two training units per week. During preseason, they trained two times per week, and during the competitive season they trained at least three times and competed in one or two games per week. RESULTS: Mean VO2max x kg(-1) was 56.7+/-4.9 ml x kg(-1) x min(-1). Mean value of maximal running speed on a treadmill with 5 percent of inclination was 12.0+/-0.9 km x h(-1). Mean values of Rmax = 1.11+/-0.07. The selected functional variables at the ventilatory threshold (VT) level corresponded to VO2 x kg(-1) = 42.9+/-5.0 ml x kg(-1) x min(-1), mean values of percent VO2max x kg(-1) at VT level were 76.5+/-1.3 percent, mean speed of running was 10.5+/-1.2 km x h(-1), mean values of percent Vmax at VT level were 87.5+/-1.9 percent. The mean of energy cost of running was 4.28+/-0.19 J x kg(-1) x m(-1). According to our results, we can conclude that the physiological characteristics of young soccer players about 8 years old should be as follows: VO2max x kg(-1) higher than 55 ml x kg(-1) x min(-1) in defenders, and higher than 60 ml x kg(-1) x min(-1), in midfielders and forwards. Maximal speed of running on the treadmill with 5 percent of inclination should be higher than 12 km x h(-1) in all players, the running speed at anaerobic threshold (5 percent) higher than 10.5 km x h(-1), percent VO2max at anaerobic threshold level higher than 77.0 percent, and the energy cost of running lower than 4.20 J x kg(-1) x m(-1). CONCLUSIONS: As in other sports where skills play a decisive role, the physiological data cannot be the sole predictor of competitive success. On the other hand, we must note that these physiological norms and standards are necessary conditions for success in high levels of soccer competition. The norms play decisive role in talent selection.     

Ventilatory threshold and maximal oxygen uptake during cycling and running in triathletes

VO2max and the ventilatory threshold (Tvent) were measured during cycle ergometry (CE) and treadmill running (TR) in a group of 10 highly trained male triathletes. Tvent was indicated as the VO2 at which the ventilatory equivalent for oxygen increased without a marked rise in the ventilatory equivalent for carbon dioxide. Triathletes achieved a significantly higher VO2max for TR (75.4 +/- 7.3 ml.kg-1.min-1) than for CE (70.3 +/- 6.0 ml.kg-1.min-1). Mean CE VO2max was 93.2% of the TR value. Average VO2max values for CE and TR compared favorably with values reported for elite single-sport athletes and were greater than those previously reported for other male triathletes. CE Tvent occurred at 3.37 +/- 0.32 l.min-1 or 66.8 +/- 3.7% of CE VO2max, while TR Tvent was detected at 3.87 +/- 0.33 l.min-1 or 71.9 +/- 6.6% of TR VO2max. The VO2 (l.min-1) at which Tvent occurred for TR was significantly higher than for CE (P less than 0.001). Although the VO2 values at TR Tvent expressed as a percentage of VO2max were consistently higher than for CE, the difference between the means did not reach statistical significance (P greater than 0.05). The average Tvent for CE (as %VO2max) was nearly identical to Tvent values reported in the literature for competitive male cyclists, whereas TR Tvent was lower than recently reported values for elite distance runners and marathoners. We speculate that triathlon training results in general (cross-training) adaptations which enhance maximal oxygen uptake values, whereas anaerobic threshold adaptations occur primarily in the specific muscle groups utilized in training.     

Physiological responses during submaximal interval swimming training: Effects of interval duration

The aim of the present study was to determine the time sustained near VO2max in two interval training (IT) swimming sessions comprising 4x400 m (IT(4x400)) or 16x100 (IT(16xl00)). Elite swimmers (Mean+/-SD age 18+/-2 yrs; body mass 66.9+/-6.5 kg: swim VO2max 55.7+/-5.8 ml.kg(-1).min(-1)) completed three experimental sessions at a 50-m indoor pool over a one week period. The first test comprised a 5 x 200-m incremental test to exhaustion for determination of the pulmonary ventilation threshold (VT, m.s(-1)), VO2max, the velocity associated with VO2max (VO2max, m(s(-1)) and maximum heart rate (HR(max), b.min(-1)). The remaining two tests involved the IT(4x400) and IT(16xl00) performed in a randomised order. The two IT sessions where completed at a velocity representing 25% of the difference between the VT and the VO2max (delta25%) and in the same work to rest ratio. During the IT sessions VO2 as well as HR were measured. The duration (s) >90% VO2max, also the duration (s) >90% HR(max), were not significantly different in the IT(16x100) and IT(4x400). However, limits of agreement (LIM(AG)) analysis demonstrated considerable individual variation in the time >90% VO2max (mean difference +/-2SD = 222+/-819 s) and the time >90% HRmax (mean difference +/-2SD = 61+/-758 s) between the two IT sessions. This factor deserves further research to establish the characteristics of those athletes which influence the physiological responses in IT of short or longer duration repetitions.     

The ventilatory threshold, heart rate, and endurance performance: relationships in elite cyclists

The purpose of this study was to investigate the validity of the ventilatory response during incremental exercise as indication of endurance performance during prolonged high-intensity exercise under field test conditions in elite cyclists. The ventilatory threshold (VT) was assessed in 14 male elite cyclists (age 22.4+/-3.4 years, height 181+/-6 cm, weight 69.2+/-6.8 kg, VO2max 69+/-7 ml x min(-1) x kg(-1)) during an incremental exercise test (20 W x min(-1)). Heart rate and oxygen uptake were assessed at the following ventilatory parameters: 1. Steeper increase of VCO2 as compared to VO2 (V-slope-method); 2. Respiratory exchange ratio (RQ)=0.95 and 1.00; 3. VE/VO2 increase without a concomitant VE/VCO2 (VE/VO2 method). Three weeks following the laboratory tests, the ability to maintain high-intensity exercise was determined during a 40 km time trial on a bicycle. During this time trial the mean heart rate (HR(TT)) and the road racing time (TT) were assessed. The V-slope-method and the VE/VO2 method showed significant correlations with TT (V-slope: r = -0.82; p<0.001; 90% interval of confidence = +/-82 sec; VE/VO2: r=-0.81; p<0.01; 90% interval of confidence = +/-81 sec). Heart rate at the ventilatory parameters and at the maximum heart rate (HRmax) showed significant correlations with HR(TT). The V-slope-method is the preferred method to predict heart rate during prolonged high-intensity exercise (r=0.93; p<0.0001; 90% interval of confidence: +/-4.8 beats x min(-1)). For predicting heart rate during prolonged high-intensity exercise using an incremental exercise test (20 W x min(-1)), without the knowledge of ventilatory parameters, we recommend using the regression formula: H(TT)=0.84 x Hmax + 14.3 beats x min(-1) (r=0.85; p<0.001).