VO2max, ventilatory and anaerobic thresholds in rhythmic gymnasts and young female dancers.

BACKGROUND: This study examines the fitness level of a rhythmic gymnasts group and a young female classical dancers group. METHODS: Aerobic power (VO2max), individual ventilatory (IVT) and anaerobic thresholds (IAT) were assessed in 12 elite rhythmic gymnasts, eight elite ballet dancers and 12 sedentary female subjects in the same age range (13-16 yrs). The VO2max, IVT and IAT were assessed during a continuous incremental running treadmill test. RESULTS: At IVT and IAT the VO2max expressed in ml x kg(-1) x min(-1) was significantly different between the three groups of subjects. The highest values were found in gymnasts (30.8+/-2.6 for IVT and 43.8+/-3.5 for IAT) followed by the values of dancers (21.7+/-2.8 for IVT and 30.5+/-3.1 for IAT) and controls (15.6+/-2.0 for IVT and 20.6+/-1.7 for IAT). When the VO2max was expressed in percent of VO2max, the values at IAT were significantly different between all groups (gymnasts: 84.9+/-0.7; dancers: 64.0+/-4.1; controls: 59.7+/-2.4) while at IVT no difference was found between dancers and controls (45.6+/-4.1 and 45.2+/-16, respectively). At maximal effort VO2 was significantly higher both in gymnasts and dancers (51.7+/-4.4 and 47.5+/-3.0 ml x kg(-1) x min(-1), respectively), than in controls (34.5+/-2.5 ml x kg(-1) x min(-1)). CONCLUSIONS: Although VO2max was similar between gymnasts and dancers, VO2 values at NT and IAT were able to discriminate the higher level of fitness in gymnasts with respect to dancers.     

The long-acting phosphodiesterase inhibitor tadalafil does not influence athletes' VO2max, aerobic, and anaerobic thresholds in normoxia

Whereas experimental studies showed that in healthy trained subjects, the phosphodiesterase-5 inhibitor (PDE-5i) sildenafil improves exercise capacity in hypoxia and not in normoxia, no studies on the effects of the long half-life PDE-5i tadalafil exist. In order to evaluate whether tadalafil influences functional parameters and performance during a maximal exercise test in normoxia, we studied 14 healthy male athletes in a double-blind cross-over protocol. Each athlete performed two tests on a cycle ergometer, both after placebo or tadalafil (at therapeutic dose: 20 mg) administration. Oxygen consumption (VO2), blood lactate, respiratory exchange ratio, rate of perceived exertion, arterial blood pressure (BP), heart frequency (HR) and oxygen pulse (VO2/HR) were evaluated before exercise, at individual ventilatory and anaerobic thresholds (IVT and IAT), at VO2max and during recovery. Compared to placebo, a single tadalafil administration significantly reduced systolic BP before and after exercise (p < 0.05), decreased VO2/HR at IVT (13.3 +/- 1.8 vs. 14.5 +/- 2.1 mL . beat (-1); p = 0.03), but did not modify individual VO2max, IVT, or IAT. In healthy athletes, 20 mg of tadalafil does not substantially influence physical fitness-related parameters, exercise tolerance, and cardiopulmonary responses to maximal exercise in normoxia; it remains to be verified if higher doses/prolonged use influence health and/or sport performance in field conditions.     

Blood lactate removal during recovery at various intensities below the individual anaerobic threshold in triathletes

AIM: Optimal lactate removal was reported to occur at work-rate between 30% and 70% VO2max. However, it has been recently recommended to quantify exercise intensity not in percentage of VO2max but in relation to validated metabolic reference points such as the individual anaerobic threshold (IAT) and the individual ventilatory threshold (IVT). The purpose of this study was to examine the effect on lactate removal of different recovery work-rates below the IAT defined calculating the difference (DT) between IAT and IVT, then choosing the IVT+50%DT, the IVT and the IVT-50%DT work-rates. METHODS: Eight male triathletes (VO2max 69.7+/-4.7, VO2IAT 52.9+/-4, VO2IVT 41.1+/-4.7 mL x kg(-1) x min(-1)), after a 6-min treadmill run at 75% of difference between IAT and VO2max, performed in a random order the following 30-min recovery treatments: 1) run at IVT(plus;50%DT), 2) at IVT, 3) at IVT(-50%DT), 4) passive. Blood lactate was measured at 1, 3, 6, 9, 12, 15, 20, 25, 30 minutes of recovery. RESULTS: All active recovery work-rates (from 50+/-5% to 67+/-4% VO2max) were within the range previously reported for optimal lactate removal, and significantly more efficient than passive recovery on lactate removal curve (% of accumulated lactate above rest value). However, significant differences (P<0.01) were found among active recovery intensities: the IVT(-50%DT) was the most efficient work-rate from the 9th minute to 30th minute. CONCLUSIONS: In triathletes, the IVT(-50%DT) was the optimal work-rate for lactate removal; moreover none of the studied active work-rate showed further lactate decrease after the 20th minute of recovery.     

Comparison of maximal oxygen uptakes from the tethered, the 183- and 457-meter unimpeded supramaximal freestyle swims

Nineteen high school swimmers (13 male and 6 female) were subjects in an investigation that compared three methods for determining maximal oxygen uptake (VO2max). Oxygen uptakes were measured during a maximal tethered swim (T), and immediately following 200-yd (183 m) and 500-yd (457 m) unimpeded supramaximal swims from a single 20-s expired gas sample. Oxygen uptakes from the 183-m and 457-m swims correlated highly with those of the T swim (r = 0.94). In addition, VO2s from the 183-m swims were very similar to the VO2s of the 457-m swims (r = 0.96). Mean (+/- SE) VO2max from the T, the 183-m, and the 457-m swims, respectively, were 3.13 (+/- 0.19), 3.20 (+/- 0.19), and 3.20 (+/- 0.17) l/min. There were no significant differences among the three means (p greater than 0.05). This study demonstrates that a single 20-s recovery gas sample from unimpeded supramaximal freestyle swims is an accurate method to determine swimming VO2max.     

Peak power output predicts rowing ergometer performance in elite male rowers

The aim of the present study was to test the hypothesis that peak power output (Ppeak) sustained during maximal incremental testing would be an overall index of rowing ergometer performance over 2000 m (P2000), and to study the influence of selected physiological variables on Ppeak. A group of 54 highly trained rowers (31 heavyweight [HW] and 23 lightweight [LW] rowers) was studied. Body mass, maximal oxygen uptake ((.-)VO(2max)), oxygen consumption corresponding to a blood lactate of 4 mmol. l (-1) expressed in percentage of (.-)VO(2max) (V.O (2)La4 %), and rowing gross efficiency (RGE) were also determined during the incremental test. In the whole group Ppeak was the best predictor of P2000 (r = 0.92, p < 0.0001). Body mass (r = 0.65, p < 0.0001), V.O (2max) (r = 0.84, p < 0.0001), (.-)VO 2)La4 % (r = 0.49, p < 0.0001) and RGE (r = 0.35, p < 0.01) were significantly correlated with P2000 as well. To take the influence of body mass into account, (.-)VO(2max) was related to kg (0.57). Ppeak was significantly related to body mass (r = 0.56, p < 0.0001), (.-)VO(2max) x kg (-0.57) (r = 0.63, p < 0.0001), (.-)VO(2)La4 % (r = 0.45, p < 0.001) and RGE (r = 0.34, p < 0.05). Multiple regression analysis indicated that the above parameters taken together explained 82.8 % of Ppeak variation in the whole group. It was also demonstrated that Ppeak was the best predictor of P2000 when LW and HW groups were considered separately. It was concluded that, by integrating the main physiological factors of performance, Ppeak is an overall index of physiological rowing capacity and rowing efficiency in heterogeneous as well as in homogeneous groups. It presents the further advantage of being easily measured in the field.     

Incremental test protocol, recovery mode and the individual anaerobic threshold

The individual anaerobic threshold (IAT) is defined as the highest metabolic rate at which blood lactate (LA) concentrations are maintained at a steady-state during prolonged exercise. The purpose of this study was to compare the effects of active and passive recovery on the determination of IAT following both a submaximal or maximal incremental exercise test. Seven males (VO2max = 57.6 +/- 5.8 ml.kg-1.min -1) did two submaximal, incremental cycle exercise tests (30 W and 4 min per step) and two maximal incremental tests. Blood was sampled repeatedly during exercise and for 12 min during the subsequent recovery period, which was passive for one submaximal and one maximal test and active (approximately 35% VO2max) during the other tests. An IAT metabolic rate and power output were calculated for the submax-passive (IATsp, LA = 1.85 +/- 0.42 mmol.l-1), max-passive (IATmp, LA = 3.41 +/- 1.14 mmol.l-1), submax-active (IATsa, LA = 2.13 +/- 0.45 mmol.l-1) and max-active (IATma, LA = 3.44 +/- 0.73 mmol.l-1) protocols. At weekly intervals, the subjects exercised for 30 min at one of the four IAT metabolic rates. Active recovery did not affect the calculation of IAT, but following the maximal incremental tests, IAT occurred at a higher (p less than 0.05) power output, absolute VO2 and %VO2max (71% VO2max) compared with the IAT determined with the submaximal incremental tests (61% VO2max).(ABSTRACT TRUNCATED AT 250 WORDS)     

The Yo–Yo intermittent recovery test in basketball players

The purpose of this study was to examine the physiological correlates of the Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1) in basketball players. Twenty-two male basketball players (means+/-S.D., body mass 72.4+/-11.4kg, height 181.7+/-6.9cm, age 16.8+/-2.0 years) were tested for maximal oxygen uptake (VO(2max)), ventilatory threshold (VT) and running economy (RE) on a motorized treadmill. Lower limb explosive strength and anaerobic-capacity was assessed using vertical jumps (CMJ), 15m shuttle running sprint (15mSR) and line drill (LD), respectively. The same test battery was replicated after an experimental basketball game in order to assess selective effect of fatigue on physical performance. Pre to post-game CMJ (40.3+/-5.7 versus 39.9+/-5.9cm) and 15mSR (5.80+/-0.25 versus 5.77+/-0.22s) performances were not significantly different (p>0.05). LD performance decreased significantly post-game (from 26.7+/-1.3 to 27.7+/-2.7s, p<0.001). Yo-Yo IR1 performances (m) were significantly related to VO(2max) (r=0.77, p=0.0001), speed at VO(2max) (r=0.71, p=0.0001) and %VO(2max) at VT (r=-0.60, p=0.04). Yo-Yo IR1 performance was significantly correlated to post-game LD decrements (r=-0.52, p=0.02). These findings show that Yo-Yo IR1 may be considered as a valid basketball-specific test for the assessment of aerobic fitness and game-related endurance.     

Aerobic requirements and maximum aerobic power in treadmill and track running.

Treadmill and track running comparisons were made on eight track athletes. Oxygen uptake (VO2) during steady-state and maximum aerobic power (VO2 max) were measured in a discrete series of three speeds, and at maximal effort. Running speeds were always in sequence from slowest to fastest. Expired air was collected from the runner by the Douglas-bag method, and analyzed by the Lloyd-Haldane technique. Neither VO2 max nor aerobic requirements of running were significantly different in track and treadmill determinations. There were several correlations: 1) VO2 max with body weight (r = .83 P less than .02), 2) treadmill and track determinations of VO2 max (r = .95, P less than .01) and 3) VO2 ml/kg with running velocity m/min (r = .91, P less than .01) where the regression was linear and may be represented by the equation Y = 5.36 + 0.172X, where Syx = 2.7 m102/kg. It is concluded that treadmill determinations of oxygen uptake may be validly applied to track running in calm air within the range of 180...260 m/min.     

Bioenergetic characteristics of swimmers determined during an arm-ergometer test and during swimming.

The maximal oxygen uptake (VO2max) of 13 swimmers was determined by an arm-ergometer test (direct method) and estimated from a maximal multistage swimming test (indirect method) (23). A test-retest of the progressive swimming exercise showed that there were no significant differences from one test to the other and that there were significant correlations between the principal parameters: arm stroke index: 0.73, maximal aerobic swimming velocity: 0.94, VO2max: 0.95, p less than 0.01. Therefore, for swimmers of average ability, the reproducibility of this test has been proved. A significant difference (p less than 0.001) was observed between the two tests for VO2max: arm-ergometer test (VO2max arms): 2.4 +/- 0.5 l.min-1, swimming test (VO2max ST): 3.2 +/- 0.7 l.min-1, p less than 0.01. This difference appeared to be linked to the use of a greater muscle mass (arms and legs) during swimming. A significant correlation (r = 0.73, p less than 0.01) was obtained between VO2max (l.min-1) by using both the direct and indirect exercises as methods of measurement. However, the level of r did not permit the prediction of one parameter from the other. Significant correlations were obtained between VO2max and performances over 200 and 400 m free style regardless of the methodology used (VO2max arm, VO2max ST). Moreover, only VO2max (arm, ST) emerged as a variable accounting for swimming performance from a step-wise multiple regression analysis, in which biometric and bioenergetic parameters were taken into account.     

Relationship between VO(2max) and repeated sprint ability using non-motorised treadmill ergometry

AIM: The aim of this study was to investigate the relationship between maximal oxygen uptake (Vo(2max)) and repeated sprint ability (RSA) using non-motorised treadmill ergometry. METHODS: Ten male participants (mean [standard deviation] VO(2max): 57.5 [2.1] mL x kg(-1).min(-1)) completed a RSA test (10, 6-s sprints with 34-s recovery) on a non-motorised treadmill. Oxygen consumption (VO(2)) and heart rate (HR) were measured during the RSA test and the decrement of performance fatigue (%(d)) was calculated for the performance indices mean maximal speed (MxSp) and average power output (AvPO). RESULTS: There were significant relationships between VO(2max) and the %(d) MxSp (r=-0.75, P<0.05) and VO(2max) and the %(d) AvPO (r=-0.69, P<0.05). There were also significant relationships between VO(2max) and HR recovery (r=0.56, P<0.05) and VO(2max) and VO(2) recovery (r=0.7, P<0.01). However, while no significant relationships were reported between HR recovery and %(d) MxSp (r= 0.45, P>0.05) and HR recovery and %(d) AvPO (r=-0.52, P>0.05), significant relationships were observed between VO(2) recovery and %(d) MxSp (r=-0.75, P<0.05) and between VO(2) recovery and %(d) AvPO (r=-0.77, P<0.05). CONCLUSION: The findings of this study suggest that VO(2max) may be an important factor determining RSA during repeated, high-intensity running-based exercise, such as field hockey, rugby and soccer.     

Both poor cardiorespiratory and weak muscle fitness are related to a high concentration of oxidized low-density lipoprotein lipids

Good physical fitness is associated with favorable serum lipids. Oxidized low-density lipoprotein (ox-LDL) could be even more atherogenic than serum lipids. We studied the association of ox-LDL and serum lipids with physical fitness. Healthy young (mean age 25 years) men (n=846) underwent maximal oxygen uptake (VO(2max) ) and muscle fitness index (MFI) tests and completed a leisure-time physical activity (LTPA) questionnaire. Age (ANCOVA1), age+waist circumference+systolic blood pressure+fasting blood glucose+smoking (ANCOVA3) were used as covariates. The groups with the lowest VO(2max) , MFI and LTPA had 23%, 16% and 8% higher concentrations of ox-LDL than the groups with the highest VO(2max) (P<0.0001), MFI (P=0.022) and LTPA (P=0.039) groups, respectively. Subjects with poor fitness (low VO(2max) or low MFI) or low LTPA had elevated levels of ox-LDL/high-density lipoprotein (HDL)-cholesterol, total cholesterol, LDL-cholesterol, triglycerides and a low level of HDL-cholesterol (ANCOVA1, in all, P<0.05). Furthermore, low VO(2max) is associated with a high level of ox-LDL/HDL-cholesterol and triglycerides, and with a low level of HDL-cholesterol (ANCOVA3, in all, P<0.05). Also, subjects with low LTPA had a high ratio of ox-LDL/HDL-cholesterol (ANCOVA1, P=0.001). In conclusion, both poor fitness (both low VO(2max) and low MFI) and low LTPA are associated with a higher concentration of ox-LDL lipids and serum lipids, which may indicate a higher risk for atherosclerosis.     

Is determination of exercise intensities as percentages of VO2max or HRmax adequate?

Often exercise intensities are defined as percentages of maximal oxygen uptake (VO2max) or heart rate (HRmax). PURPOSE: The purpose of this investigation was to test the applicability of these criteria in comparison with the individual anaerobic threshold. METHODS: One progressive cycling test to exhaustion (initial stage 100 W, increment 50 W every 3 min) was analyzed in a group of 36 male cyclists and triathletes (24.9 +/- 5.5 yr; 71.6 +/- 5.7 kg; VO2max: 62.2 +/- 5.0 mL x min(-1) x kg(-1); individual anaerobic threshold = IAT: 3.64 +/- 0.41 W x kg(-1); HRmax: 188 +/- 8 min). Power output and lactate concentrations for 60 and 75% of VO2max as well as for 70 and 85% of HRmax were related to the IAT. RESULTS: There was no significant difference between the mean value of IAT (261 +/- 34 W, 2.92 +/- 0.65 mmol x L(-1)), 75% of VO2max (257 +/- 24 W, 2.84 +/-0.92 mmol x L(-1)), and 85% of HRmax (259 +/- 30 W, 2.98 +/- 0.87 mmol L(-1)). However, the percentages of the IAT ranged between 86 and 118% for 75% VO2max and 87 and 116% for 85% HRmax (corresponding lactate concentrations: 1.41-4.57 mmol x L(-1) and 1.25-4.93 mmol x L(-1), respectively). The mean values at 60% of VO2max (198 +/- 19 W, 1.55 +/- 0.67 mmol x L(-1)) and 70% of HRmax (180 +/- 27 W, 1.45 +/- 0.57 mmol x L(-1)) differed significantly (P < 0.0001) from the IAT and represented a wide range of intensities (66-91% and 53-85% of the IAT, 0.70-3.16 and 0.70-2.91 mmol x L(-1), respectively). CONCLUSIONS: In a moderately to highly endurance-trained group, the percentages of VO2max and HRmax vary considerably in relation to the IAT. As most physiological responses to exercise are intensity dependent, reliance on these parameters alone without considering the IAT is not sufficient.     

An association between aerobic fitness and lung closing volume

This study was performed to determine whether an association exists between relative aerobic fitness (fitness index) and lung closing volume (CV). The subject population consisted of 100 healthy nonsmoking adults (50 males and 50 females) divided equally into five age groups; 20-29, 30-39, 40-49, 50-59, and over 60 years. Each subject underwent four to six closing volume and forced vital capacity (FVC) tests followed by a modified Balke maximal oxygen uptake test on a motor-driven treadmill with a constant treadmill speed. Relative VO2 maximum (VO2 max, mlO2 X kg-1 X min-1) was determined from the exercise test and was used to define subject rank on the fitness index. CV, as a % of slow vital capacity (SVC), had a negative linear correlation (r = -0.53, P less than 0.05) with the fitness index. Slope of phase III (%N2/L) and FEV1/FVC (forced expired volume in 1 s as a % of forced vital capacity) also had significant correlation coefficients (r = -0.31, r = 0.24, respectively; both P less than 0.05) with the fitness index. The correlation coefficients, with age partialled from the relationships, between FVC/body weight (kg) and VO2 max were r = 0.59 for females and r = 0.43 for males (P less than 0.05, both groups). We hypothesize that the effects of aerobic fitness on lung function may be the result of changes in autonomic nervous system activity and may represent a situation where a high level of aerobic fitness affects the aging process of the lung beta-adrenergic nervous system.     

Children's OMNI Scale of Perceived Exertion: walking/running evaluation

PURPOSE: The Children's OMNI-walk/run Scale of Perceived Exertion (category range, 0-10) was evaluated using male and female children (6-13 yr of age) during a treadmill graded exercise test. METHODS: A cross-sectional, perceptual estimation paradigm using a walking/running test protocol was administered. Oxygen uptake (VO(2), mL x min(-1)), %VO(2max), ventilation (VE, L x min(-1)), respiratory rate (RR, breaths x min(-1)), respiratory exchange ratio (RER), heart rate (HR, beats x min(-1)), V(E)/VO(2) ratio, and ratings of perceived exertion (RPE) measurements were made every minute throughout the test. RESULTS: Significant correlations were found between OMNI-walk/run Scale RPE responses and VO(2), %VO(2max), HR, V(E)/VO(2) ratio, and RR throughout the maximal treadmill exercise test. The strongest correlations were found between RPE and %VO(2max) (r = 0.41-0.60, P < 0.001) and HR (r = 0.26-0.52, P < 0.01). CONCLUSION: The psychophysiological responses provide validity evidence for use of the Children's OMNI-walk/run Scale over a wide range of exercise intensities during both walking and running.     

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.     

The 1-mile walk test is a valid predictor of VO(2max) and is a reliable alternative fitness test to the 1.5-mile run in U.S. Air Force males

The purpose of this study was to assess the validity of the 1-mile walk (Rockport Walk Test) as a predictor of VO(2max) and determine whether the 1-mile walk is a reliable alternative to the 1.5-mile run in moderately fit to highly fit U.S. Air Force males. Twenty-four (33.0 +/- 1.5 years) males completed a maximal treadmill VO(2max) (50.3 +/- 1.4 mL/ kg/min), 1-mile walk, and 1.5-mile run. For the 1-mile walk, there were no significant differences between measured and predicted VO(2max) (p = 0.177, r = 0.817). There were no significant differences (p = 0.573) between points scored in the Air Force Fitness Test for the 1-mile walk and 1.5-mile run tests. In conclusion, the 1-mile walk test is a valid predictor of VO(2max) and can be used as an alternative fitness test to the 1.5-mile run in assessing cardiovascular fitness in Air Force males.     

Effect of exercise intensity on relationship between VO2max and cardiac output

PURPOSE: The purpose of this study was to determine whether the maximal oxygen uptake (VO2max) is attained with the same central and peripheral factors according to the exercise intensity. METHODS: Nine well-trained males performed an incremental exercise test on a cycle ergometer to determine the maximal power associated with VO2max (pVO2max) and maximal cardiac output (Qmax). Two days later, they performed two continuous cycling exercises at 100% (tlim100 = 5 min 12 s +/- 2 min 25 s) and at an intermediate work rate between the lactate threshold and pVO2max (tlimDelta50 +/- 12 min 6 s +/- 3 min 5 s). Heart rate and stroke volume (SV) were measured (by impedance) continuously during all tests. Cardiac output (Q) and arterial-venous O2 difference (a-vO2 diff) were calculated using standard equations. RESULTS: Repeated measures ANOVA indicated that: 1) maximal heart rate, VE, blood lactate, and VO2 (VO2max) were not different between the three exercises but Q was lower in tlimDelta50 than in the incremental test (24.4 +/- 3.6 L x min(-1) vs 28.4 +/- 4.1 L x min(-1); P < 0.05) due to a lower SV (143 +/- 27 mL x beat(-1) vs 179 +/- 34 mL x beat(-1); P < 0.05), and 2) maximal values of a-vO2 diff were not significantly different between all the exercise protocols but reduced later in tlimDelta50 compared with tlim100 (6 min 58 s +/- 4 min 29 s vs 3 min 6 s +/- 1 min 3 s, P = 0.05). This reduction in a-vO2 diff was correlated with the arterial oxygen desaturation (SaO2 = -15.3 +/- 3.9%) in tlimDelta50 (r = -0.74, P = 0.05). CONCLUSION: VO2max was not attained with the same central and peripheral factors in exhaustive exercises, and tlimDelta50 did not elicit the maximal Q. This might be taken into account if the training aim is to enhance the central factors of VO2max using exercise intensities eliciting VO2max but not necessarily Qmax.     

The influence of training on endurance and blood lactate concentration during submaximal exercise.

The purpose of this study was to examine the effect of short-term training on maximum oxygen uptake (VO2 max) and two different measures of endurance performance. Endurance was determined for 15 female subjects (7 training, 8 control) as (1) exercise time to exhaustion at 80% VO2 max (T80%) and (2) the highest relative exercise intensity tolerable during a 30-minute test (T30 min), before and after a 6-week training period. In addition, VO2 max and the work rate equivalent to a blood lactate concentration of 4 mmol.l-1 (OBLA) were determined. Maximum oxygen uptake increased by 24% (p less than 0.01) for the training group (TG) and 7% (p less than 0.01) for the control group (CG). Cumulative average work rate (CAWR) during T30 min increased by 25% for the TG while there was no change for the CG. No significant difference was found pre- and post-training in the %VO2 max (estimated from CAWR) at which the TG and CG performed T30 min. Exercise time to exhaustion on T80% increased by 347% (p less than 0.01) and 16% (NS) for the TG and the CG respectively. Good correlations were found between VO2 max and CAWR (W) (pre-training r = 0.84; post-training r = 0.83), OBLA (W) and CAWR (W) (pre-training r = 0.89; post-training r = 0.88) and change in endurance time and the change in submaximal blood lactate concentration (r = 0.70, p less than 0.01). The results of this study suggest that the ability to sustain a high relative exercise intensity is not enhanced following short-term training.     

Determinants of five kilometre running performance in active men and women.

Previous studies of elite endurance athletes have suggested that success in distance running is attributable to the possession of a high maximal oxygen uptake (VO2 max), the utilisation of a large fraction of the VO2 max and to running economy. The purpose of the present study was to examine the relationships between these physiological characteristics and running performance in active but not elite men and women. Maximal oxygen uptake values were 57.6 +/- 6.2 and 46.6 +/- 4.8 ml . kg.-1 min-1 for the men and women respectively (p less than 0.01). Running performance was assessed as a 5 km time trial and the men completed this distance in 19.77 +/- 2.27 min and the women in 24.44 +/- 3.19 min (p less than 0.01). Maximal oxygen uptake showed strong correlations (p less than 0.01) with running performance (men, r = -0.85; women, r = -0.80) but there was only a modest relationship between running economy and performance (men, r = 0.39; women, r = 0.34). The results of the present study suggest that the faster 5 km performance times recorded by the men were best explained by their higher VO2 max values.