Impaired oxygen uptake kinetics in the first high-level athlete with Hb Hope: a case study.

Hemoglobin (Hb) Hope is a beta-globin chain variant with reduced oxygen (O2) affinity, known to induce anemia. This usually leads to limitations in O2uptake (VO2) and exercise tolerance. We studied the case of a high-level female athlete with Hb Hope. She had been selected for cross-country races from 13 yrs onward, then was a national junior champion in 400-m race, and finally failed to win any cross-country races as an adult. Hematological analysis revealed normal red blood cell indices and Hb level (12.3 g.dL⁻¹). Incremental exercise showed peak work rate (WR), VO(2max) and gas exchange threshold (GET) within normal ranges for healthy females. Constant WR testing at 90% of GET showed that kinetics of pulmonary VO2included the presence of a slow component. This was in disagreement with the data on VO2kinetics response to exercise intensities below GET. Phase 2 parameters, time constant (τ2, 31 s), time delay (TD2, 39 s), amplitude (A2, 780 ml.min⁻¹), and gain in VO2(ΔVO2 .ΔWR-1, 9.2 ml.min-1.W⁻¹) were within normal ranges. Phase 3 showed a slow component similar to that reported in severe exercise. The absence of anemia and the normality of phase 2 suggested normal O2delivery and oxidative metabolism in exercising muscles. In contrast, phase 3 suggested poor aerobic capacity and limited exercise tolerance. However, the lack of symptoms during testing also suggested that the slow component was due to the specific recruitment of fast-twitch fibers in this former champion athlete with Hb Hope in races requiring mainly anaerobic metabolism.

High plasmatic angiotensin-converting enzyme (ACE) activity is not correlated with training-induced left ventricular growth in ACE congenic rats.

AIM: The aim of this study was to determine the influence of angiotensin-converting enzyme (ACE) genotype on left ventricular growth after endurance training, in ACE congenic rats with plasma ACE activity twice as high as the donor strain (LOU), thus mimicking the ACE I/D polymorphism observed in humans. METHODS: LOU and congenic rats (n = 12) were submitted to an endurance training on a treadmill for 7 weeks, while similar LOU and congenic rats (n = 10) constituted the control groups. Blood pressure, skeletal muscle citrate synthase activity, plasma and left ventricular ACE activity were assessed, and echocardiography was performed before and after the training. RESULTS: Angiotensin-converting enzyme plasmatic activity of congenic rats (188.2 +/- 26.6 in controls and 187.1 +/- 22.6 IU in trained rats respectively) was twofold that of the LOU strain (91.9 +/- 23.3 in controls, and 88.3 +/- 18.1 IU in trained rats respectively). After training, congenic and LOU rats showed a similar significant increase in citrate synthase activity (P < 0.05), and in the left ventricular mass/body mass ratio x 10(3): 3.7 +/- 0.3 and 3.6 +/- 0.6 in the trained congenic and LOU groups, respectively, vs. 3.0 +/- 0.1 and 2.9 +/- 0.2 in the control congenic and LOU groups respectively (P < 0.05). There was no significant correlation between ACE plasma activity and left ventricular mass in trained or untrained congenic rats. CONCLUSION: We conclude that training-induced left ventricular growth is not associated with plasma ACE activity in congenic rats.

The performance and efficiency of cycling with a carbon fiber eccentric chainring during incremental exercise.

AIM: The aim of this study was to compare cycling performance and efficiency of a carbon fiber eccentric chainring (EC) versus a metallic standard chainring (SC) during an incremental exercise. The main feature of EC was that crank-arm length changed as a function of the crank angle, being maximal during the pushing phase and minimal during the recovery one. Because of its design, cycling with EC was expected to develop higher torque during the downstroke, and lower torque during the upstroke, thus increasing mechanical efficiency and requiring lower cardioventilatory solicitation at submaximal exercise intensities. METHODS: Eleven male subjects performed two incremental cycle tests in a randomized order using EC and SC successively. Cardioventilatory data were recorded every minute using an automated breath-by-breath system. Blood samples were taken at rest, exhaustion, 5 and 15 minutes of recovery to access lactate concentrations, [LA], mmol . L(-1) . RESULTS: The subjects reached significantly lower maximal speed at volitional exhaustion with EC compared with SC (39.4+/-2.5 versus 41.5+/-2.9 km . h(-1), respectively; P<0.05). Analysis of variance revealed significantly higher values for oxygen uptake and carbon dioxide production during incremental exercise with EC (P<0.05). Lastly, [LA] at exhaustion were similar with the two chainrings. CONCLUSIONS: The carbon fiber EC tested in this study failed to enhance cycling performance and efficiency throughout an incremental exercise. This indicated that carbon fibers did not exhibited its expected mechanical advantage.

Salivary IgA response of triathletes participating in the French Iron Tour.

Athletes are susceptible to upper respiratory tract infections (URTI) during intense training and after major competitions. Secretory IgA, which is the predominant antibody of the mucosal immune system, is the major effector of host-resistance to many microorganisms causing URTI. Previous studies have shown that salivary IgA-mediated immunity decreases after a single short distance triathlon, but the effect of repeated triathlon competitions on secretory IgA levels remains unknown. The purpose of this study was to examine the salivary IgA response of elite triathletes in repeated triathlon races during the 2001 French Iron Tour (FIT). Eight triathletes participated in this study. Saliva samples were collected daily after waking up (fasting basal state), before (pre-race) and after (post-race) each day's competition. Salivary IgA, total protein, and flow rate were measured. Salivary IgA concentrations were measured by an enzyme-linked immunosorbent assay. The salivary flow rate was significantly decreased after each race compared with the fasting basal state (p < 0.01). The salivary IgA concentration of the fasting basal state decreased over the FIT and was even lower than that of the post-race values (p < 0.05). The salivary IgA secretion rate of the fasting basal state decreased by 51.9% over the FIT (p < 0.05). Our data suggest that intense exercise repeated daily has a cumulative negative effect on basal levels of salivary IgA.

Non-linear analyses of heart rate variability during heavy exercise and recovery in cyclists.

We investigated the time course of RR interval variability during exercise and subsequent 50 minutes of recovery in seven well-trained male cyclists who performed an exercise with 3 successive 8 min stages at 40 %, 70 % and 90 % of their maximal oxygen uptake. The goal of the study was to check whether the decrease in the amplitude of heart rate variability during heavy exercise was accompanied by changes in the chaotic structure of the fluctuations. Heart rate variability was analysed in the temporal and frequency domain using traditional tools and using non-linear methods (Largest Lyapunov Exponent, Detrended Fluctuation Analysis, Minimum Embedding Dimension). When compared to rest, variability at the heaviest exercise intensity was significantly lower (RR: 0.94 +/- 0.22 vs. 0.34 +/- 0.01 ms; SDRR: 0.11 +/- 0.04 vs. 0.01 +/- 0.00 ms) due to a decrease in both LF (2101 +/- 1450 vs. 0.14 +/- 0.09 ms (2) . Hz (-1)) and HF spectral energy (1148 +/- 1126 vs. 7.88 +/- 9.24 ms (2) . Hz (-1)). Non-linear analyses showed that heart rate variability remained chaotic whatever the exercise intensity (the largest Lyapunov exponent was positive at 90 % of the maximal oxygen uptake), with a fractal organisation that tended towards white noise (DFA value close to 0.5) during heavy exercise. During recovery, temporal and spectral variables came back to their rest values within about 30 minutes following an exponential pattern. Non-linear analyses revealed that heartbeat dynamics were disorganised at the beginning of recovery, and involved more regulating systems than at rest, even after 50 minutes of recovery. We concluded that, during heavy exercise, heart rate variability was mainly influenced by other factors than autonomous nervous system, and suggest that mechanical or neurological couplings between the cardiac, locomotor and respiratory systems could play an important part in the observed changes.

High versus low training frequency in cardiac rehabilitation using a systems model of training.

No study has reported the long term effects of cardiac rehabilitation, concerning the duration of beneficial effects of training program. The present study analyzed the influence of training session frequency on long-term beneficial effects in patients with coronary artery disease (CAD) undergoing phase 2 cardiac rehabilitation. Four patients with CAD completed 20 training sessions. Two patients were assigned to low training frequency (LTF) and two to high training frequency (HTF): three and five sessions per week(-1), respectively. The method was based on the systems model of training and required training quantification and the assessment of real exercise tolerance. Convolution of training quantity with real exercise tolerance provided the model exercise tolerance for every patient. The model parameters, the magnitude factor (k), and the time constant of decay (tau), were fitted from real and model exercise tolerances by the least squares method. LTF and HTF resulted in similar increases in exercise tolerance (12-14%). A model with one-component (fitness) allowed fitting exercise tolerance in all patients with r (2) = 0.77, 0.79, 0.84, and 0.91, respectively (p < 0.05). The addition of a second component did not improve the fit in any patient (p > 0.05). The k value was about twice as high with LTF (0.13 and 0.16 AU) than with HTF (0.05 AU for the two patients), whereas the tau value was about twice as low with LTF (37 and 41 days) than with HTF (72 and 89 days). The long term beneficial effects estimated by 4tau, were twice as long with HTF (288 and 356 days) than with LTF (148 and 164 days). We concluded that exercise tolerance was similarly increased with HTF and LTF but HTF training induced beneficial effects which were sustained twice as long.

Is exercise-induced arterial hypoxemia in triathletes dependent on exercise modality?

To determine whether exercise modality affects arterial hypoxemia (EIAH) during training-intensity exercise, 13 triathletes performed 20 min of cycling (C) followed by 20 min of running (R): C-R, and two weeks later, 20 min of R followed by 20 min of C:R-C. Each trial was performed at an intensity slightly above the ventilatory threshold and close to the daily training intensity (75 % of VO2max). Ventilatory data were collected continuously using an automated breath-by-breath system. Partial pressure of oxygen in arterial blood (PaO2) was measured after each C and R segment and arterial oxyhemoglobin saturation (SpO2) was monitored continuously via pulse oximetry. The metabolic rate was similar across modalities and trials, i.e., C-R (53.8 +/- 3.8 vs. 51.1 +/- 5.3 ml.min(-1).kg(-1)) and R-C (52.2 +/- 4.5 vs. 53.2 +/- 4.6 ml.min(-1).kg (-1)). EIAH showed significantly greater severity for R compared to C irrespective of the order (p < 0.05 for both trials). R values of PaO2 (and SpO2) for C-R and R-C were 88.7 +/- 6.0 mm Hg (93.0 +/- 0.6 % SpO2) and 86.6 +/- 7.3 mm Hg (93.5 +/- 0.6 % SpO2) and C values were 93.7 +/- 8.4 mm Hg (95.4 +/- 0.4 % SpO2) and 91.4 +/- 5.4 mm Hg (94.8 +/- 0.3 % SpO2). R ventilatory data described a significantly different breathing pattern than C, with higher respiratory rate (35.9 b.min(-1) vs. 51.1 b.min(-1) for C-R, p < 0.01; and 50.0 b.min(-1) vs. 41.5 b.min(-1) for R-C, p < 0.01) and lower tidal volume (2636 ml vs. 2282 ml for C-R, p < 0.02 and 2272 ml vs. 2472 ml for R-C, p < 0.05). We concluded that EIAH was greater during running than cycling for a similar metabolic rate corresponding to training intensity and that EIAH could thus be considered dependent on exercise modality.

Sickle cell trait in French West Indian elite sprint athletes.

The aim of this study was to establish the percentage of sickle cell trait (SCT) carriers among French West Indian sprinters selected for the French National Team in 2000. The investigation determined the number of SCT carriers and the number of national records they had established. Sixteen athletes were indexed (6 males and 10 females). The athletes were within the ranges of 20-33 years, 161-186 cm and 60-80 kg. The results showed the presence of SCT carriers in this population among whom three were SCT carriers (2 males and 1 female) (18.75%). Moreover, there is a significantly higher percentage of titles and records held by the SCT carriers (38.6% and 50%, respectively). In conclusion, this study shows that sickle cell trait carriers are able to perform sprint exercises at the highest levels, and it further indicates that brief and explosive exercise involving mainly the alactic anaerobic metabolism may be enhanced by HbS.

Effects of successive running and cycling on the release of atrial natriuretic factor in highly trained triathletes.

AIM: To evaluate the influence of successive running and cycling on both exercise-induced arterial hypoxemia (EIAH) and atrial natriuretic factor (ANF) release, 5 triathletes performed 2 separate exercise trials. METHODS: One trial consisted of a 20-min+20-min successive cycle-run exercise (C(1)-R(2)) and the other consisted of a 20-min+20-min successive run-cycle exercise (R(1)-C(2)). Arterial oxygenation (PaO(2)) and ANF were determined at pre-exercise, at the end of each 20-min segment of exercise and after 10 min of recovery. RESULTS: EIAH was noted during C(1)-R(2) and R(1)-C(2) trials. A higher EIAH was observed during running compared with cycling performed in the 1(st) position (R(1) vs C(1)) in the succession. In contrast, no difference was observed between successive running and successive cycling (R(2) vs C(2)), (-10.6+/-7.0 vs -15.6+/-4.0 mmHg for C(1)-R(2) and -20.9+/-6.0 vs -16.2+/-2.4 mmHg for R(1)-C(2)). ANF showed no difference between cycling and running performed in first position, whereas a significantly lower ANF was observed during successive cycling compared with successive running (C(2) vs R(2)) (19.9+/-3.72 vs 36.2+/-6.4 pmol.L(-1)). During recovery, neither PaO(2) nor ANF plasma returned to baseline level after either trial. CONCLUSION: This study provides new information on some of the physiological modifications that occur during multi-sports. Specifically, the impact of the modality of the successive exercise on ANF release and body fluid regulation was observed. Cycling as the successive exercise seems to cause lower ANF release than does running.

Does systemic inflammation trigger local exercise-induced oxidative stress in COPD?

Inflammatory abnormalities may be involved in the inadequate basal oxidant/antioxidant balance and local exercise-induced oxidative stress in chronic obstructive pulmonary disease (COPD) patients. The time course of oxidative stress and inflammation was investigated in 10 COPD patients and seven healthy subjects before and after local dynamic quadriceps endurance exercise at 40% of maximal strength. Venous samples were collected before, immediately after and up to 48 h after exercise. At rest, levels of an oxidant released by stimulated phagocytes, the superoxide anion, were significantly higher in patients, as were plasma levels of C-reactive protein, tumour necrosis factor-alpha and interleukin-6, inflammatory markers. An inverse relationship was found between baseline C-reactive protein levels and endurance time in patients. Six hours after exercise, superoxide anion release and levels of protein oxidation products, an index of oxidative stress, increased similarly in both groups, whereas thiobarbituric acid reactive substance levels, another index of oxidative stress, increased significantly only in patients. Plasma nonenzymatic antioxidant and inflammatory cytokine levels were unchanged by the exercise protocol. The increased baseline systemic inflammation in chronic obstructive pulmonary disease patients could be related to disturbed oxidant/antioxidant balance, and, together, these may have triggered the exercise-induced oxidative stress. The absence, however, of local exercise-induced systemic inflammation suggests that additional mechanisms explain local exercise-induced oxidative stress.

Effect of sleep deprivation on shuttle run score in middle-aged amateur athletes. Influence of initial score.

AIM: The aim of the present study was to investigate the effect of sleep deprivation on shuttle run score (corresponding to an estimated VO2 peak) in middle-aged amateur athletes. METHODS: Twenty-two athletes, training 9.2 hours a week (+/-4), performed a Leger and Gadoury shuttle test daily in a 4-day series that included a pre-test in day 0, 28 hours without sleep before test 1 (and 10 another hours after the test and before bedtime for a sleep deprivation of 38 hours), and then 10 hours of sleep before each of days 2 and 3. RESULTS: Shuttle run score showed no significant difference over the 4 days; however, the change in shuttle run score on day 2 was significantly correlated with the initial score. CONCLUSIONS: This result suggests that effect of sleep deprivation on shuttle run score is dependent on initial score and may encourage high level aerobic athletes to avoid sleep deprivation 2 days before a competition.

Pulmonary function during cycling and running in triathletes.

AIM: Running performance has become key to the triathlete's overall performance. We still know relatively little about the factors that define the ability to perform a good run after cycling, however, and the perception of discomfort during the first minutes of this post-cycling running has yet to be satisfactorily explained. Pulmonary volumes (i.e., residual volume, RV, and functional residual capacity, FRC) have been demonstrated to be impaired after a cycle-run succession in triathletes but not after a run-run succession that is matched in terms of intensity and duration. Cycling in itself and/or the succession of two different exercises (i.e., cycling and running) may explain this phenomenon, but the exact mechanism has not yet been determined. METHODS: Thirteen young male triathletes participated in three different exercise trials: 30 min of cycling followed by 20 min of running (C-R), 30 min of control cycling (C) and 20 min of control running (R). Pulmonary volumes and flows were measured 10 min before and 10 min after each trial. During all trials, ventilatory data were collected every minute using an automated breath-by-breath system. RESULTS: The results showed that 1) C induced significant increases in RV, FRC and RV/TLC (2.31+/-0.18 vs 2.01+/-0.17 L, 4.35+/-0.24 vs 4.01+/-0.25 L, and 27.21+/-1.62 vs 23.98+/-1.55, respectively, after versus before C) and 2) there were no significant pulmonary volume or flow changes after C-R or R. CONCLUSION: We concluded that 1) cycling exercise in itself seems to increase the post-exercise pulmonary volume changes which could lead to respiratory muscle alterations and 2) one likely explanation for this finding appears to be the crouched position of cycling.

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

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) and T(lim) (5.22 +/- 0.28 versus 3.68 +/- 0.32 min, p < 0.05) post-C and post-C-R (133.7 +/- 4.0 versus 126.9 +/- 5.2 cm H2O, and 5.29 +/- 0.18 versus 3.49 +/- 0.41 min, respectively, p < 0.05) compared with the pre-trial values. In contrast, P(Imax) and T(lim) were not significantly decreased post-R (131.8 +/- 6.1 cm H2O versus 129.6 +/- 6.4 cm H2O, and 4.90 +/- 0.69 versus 4.40 +/- 0.56 min, respectively, 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.

Prediction of VO(2peak) in wheelchair-dependent athletes from the adapted Léger and Boucher test.

PURPOSE: :The purpose of this study was to provide a predictive peak oxygen uptake ([V]O(2) peak) equation in wheelchair-dependent athletes using the Adapted Léger and Boucher test. SUBJECTS AND PROTOCOL: :Fifty-six wheelchair-dependent athletes, 47 males and nine females (30.3+/-4 years), underwent a clinical examination to assess their anthropometric characteristics: height, mass, body mass index (BMI), lean body mass, arm length, and muscular arm volume. They performed a deceleration field test to assess the subject-wheelchair resistance defined as a mechanical variable, and they then performed the Adapted Léger and Boucher test to assess physiological data at maximal exercise ([V]O(2) peak, heart rate max) concomitantly with biomechanical (number of pushes) and performance variables (maximal aerobic velocity Va(max) and maximal distance). The [V]O(2) peak was measured directly using a portable telemetric oxygen analyzer. Subjects were then randomly assigned to an experimental group (n=49) to determine the predictive equation, and a validation group (n=7) to check the external validity of the equation. RESULTS: A stepwise multiple regression with [V]O(2) peak (l min(-1)) as the dependent variable led to the following equation: [V]O(2) peak=0.22 Va(max) - 0.63 log(age)+0.05 BMI 0.25 level+0.52, with r(2)=0.81 and SEE=0.01. Paraplegic subjects with high and low lesion level spinal injuries were attributed the coefficient of 1 and 0, respectively. The external validity of the equation was positive since the predicted [V]O(2) peak values did not significantly differ from directly measured [V]O(2) peak (P>0.05). CONCLUSION: We concluded that [V]O(2) peak in wheelchair-dependent athletes was predictable using the equation of the present study and the described incremental test.

The effect of cycling followed by running on respiratory muscle performance in elite and competition triathletes.

This study investigated the possibility of there being differences in respiratory muscle strength and endurance in elite and competition triathletes who have similar maximal oxygen uptakes (VO(2max)) and ventilatory thresholds (Th(vent)). Five internationally-ranked elite, [mean (SD) age 23.8 (1.4) years] and six nationally- and regionally-ranked competition [age 21.1 (1.1) years] male triathletes performed two successive trials: first an incremental cycle test to assess VO(2max) and Th(vent) and second 20 min of cycling followed by 20 min of running (C-R) at intensities higher than 85% VO(2max). Cardioventilatory data were collected every minute during the two trials, using an automated breath-by-breath system. Maximal expiratory and inspiratory (P(Imax)) strength were assessed before and 10 min after C-R from the functional residual capacity. Respiratory muscle endurance was assessed 1 day before and 30 min after C-R by measuring the time limit (t(lim)). The results showed firstly that during C-R, the competition triathletes had significantly (P < 0.05) higher minute ventilation [mean (SEM) 107.4 (3.1) compared to 99.8 (3.7) l x min(-1)], breathing frequency [44.4 (2.0) compared to 40.2 (3.4) x min(-1)] and heart rate [166 (3) compared to 159 (4) beats x min(-1)] and secondly that after C-R, they had significantly lower P(Imax) [127.1 (4.2) compared to 130.7 (3.0) cmH(2)O] and t(lim) [2:35 (0:29) compared to 4:12 (0:20) min] than the elite triathletes. We conclude that, despite similar VO(2max) and Th(vent), the competition triathletes showed less extensive adaptive mechanisms, including those in the respiratory muscles, than did the elite triathletes. This led to higher ventilation, which appeared to be the cause of the faster development of fatigue in the inspiratory muscles in this group.

Cardiorespiratory responses and blood lactate during an experimental run-cycle transition in duathletes.

The aim of this study was to determine the effects of a prior run on the cardiorespiratory responses measured during a subsequent cycle segment. Twelve duathletes underwent three successive laboratory trials at an interval of one week: 1) an incremental cycle test, 2) 20 min of running followed by 20 min of cycling (RC), and 3) 20 min of control cycling (C) at the same intensity as the cycling segment of RC. Ventilatory data were collected every minute using a breath-by-breath automated system. Blood samples were collected to measure venous blood lactate concentration, [La], at rest, after the running and cycling segments of RC and after C. The results showed that the C segment of RC had significantly higher VE, VE/VO2, f and HR than C alone and significantly lower VT (p < 0.05) than C alone. Moreover, steady state during C of RC was reached at the 2nd min for VO2, VE, VCO2, VE/VO2, VE/VCO2, and VdT; at the 4th min for R and HR, and at the 5th min for f. The C of RC induced a significant increase in [La] in comparison with C alone. We concluded that the first minute of cycling after running during an RC trial induced specific metabolic and cardiorespiratory responses.

Alactic anaerobic performance in subjects with sickle cell trait and hemoglobin AA.

The aim of the present study was to assess the performance of subjects with sickle cell trait (SCT) during brief and explosive exercise involving mainly anaerobic metabolism. One hundred and ninety-six black subjects underwent SCT screening, which revealed the presence of 16 subjects with SCT and 180 subjects with normal hemoglobin (HbAA). All subjects performed four tests: 1) a 100-m sprint, 2) a long-jump, 3) a Leger-Boucher shuttle test and 4) a jump-and-reach test. A control group (n = 18) selected from the 180 subjects with HbAA was matched according to the sex, age, weight and height of the SCT subjects (SCTs). The performances of the SCTs (n = 16) were compared with those of the control group. The performances were similar between the SCTs and control group for the sprint test, long-jump and the Leger-Boucher shuttle test. There was, however, a significant difference for the jump-and-reach test between the two groups: the SCTs (i. e., males plus females, and males and females considered separately) reached a significantly greater height (p < 0.05) than the matched subjects of the control group (63.7 +/- 3.6 vs. 58.6 +/- 3.1 cm, 72.3 +/- 3.9 vs. 67.1 +/- 2.4 cm and 52.7 +/- 3.2 vs. 45.3 +/- 2.0 cm for SCTs versus non-SCTs, for the group, the males and the females, respectively). The results of the present study suggest that the performance of brief and explosive exercise may be enhanced by HbS.

The effect of exercise modality on respiratory muscle performance in triathletes.

PURPOSE: The aim of this study was to examine the effects of the cycle-run and run-cycle successions of the triathlon and duathlon, respectively, on respiratory muscle strength and endurance. METHODS: Respiratory muscle strength was assessed by measuring maximal inspiratory (P(Imax)) and expiratory (P(Emax)) pressures. Respiratory muscle endurance was assessed by measuring the time limit (T(lim)). Twelve triathletes participated in a three-trial protocol. The first trial consisted of an incremental cycle test to assess the maximal oxygen uptake (.VO(2max)) of triathletes. Trial 2 consisted of 20 min of cycling followed by 20 min of running (C-R), and trial 3 consisted of 20 min of running followed by 20 min of cycling (R-C). Trials 2 and 3 were performed at the same metabolic intensity (%.VO(2max)). P(Imax) and P(Emax) were measured before and 10 min after C-R and R-C, and 1 min after the post-C-R and post-R-C T(lim) measurements (P(Imax) 1'). T(lim) was measured 1 d before and 30 min after C-R and R-C. RESULTS: The results showed a significant decrease in P(Imax) after C-R (126.7 +/- 4.3 cmH(2)O, P < 0.05) and R-C (123.7 +/- 4.9 cmH(2)O, P < 0.05) compared with the baseline values (130 +/- 3.8 and 129.6 +/- 4.3 cmH(2)O, respectively). P(Imax) 1' showed a significantly greater decrease after R-C versus C-R (111.2 +/- 5.5 cmH(2)O vs 121.2 +/- 3.9 cmH(2O), respectively, P < 0.001). Tlim after C-R (3.3 +/- 0.3 min) and R-C (2.1 +/- 0.3 min) decreased significantly compared with baseline values (4.19 +/- 0.3 min and 4.02 +/- 0.3 min, respectively). However, the Tlim decrease after R-C was significantly greater than after C-R (P < 0.001). CONCLUSION: We concluded that respiratory muscle strength and endurance were less decreased after the cycle-run succession and that cycling induced a greater decrease in respiratory muscle endurance than running.

DLCO response to experimental cycle-run succession in triathletes.

BACKGROUND: We still know relatively little about the factors that define the ability to perform a good run after cycling in triathlon, however, and the perception of discomfort during the first minutes of this post-cycling running has yet to be satisfactorily explained. The pulmonary diffusion capacity for carbon monoxide (DLCO) has been demonstrated to be impaired after the cycle-run succession. Numerous causes have been suggested to explain this phenomenon, but the exact mechanism has not yet been determined. METHODS: Thirteen young male triathletes participated in four different exercise trials: 30 min of cycling followed by 20 min of running (C-R, 1 min rest between C and R), 30 min of running followed by 20 min of running (R-R, 1 min rest between R and R), 30 min of cycling (C), and 30 min of running (R). DLCO and alveolar volume were simultaneously measured during 9 sec of breath-holding before and 10 min after exercise. The transfer coefficient (KCO=DLCO/VA) was then calculated. During all trials, ventilatory data were collected every minute using an automated breath-by-breath system. RESULTS: The results showed that 1) C-R and C induced significant and identical decreases in DLCO and KCO in post-trial compared with pre-trial measurement (40.41+/-2.24 vs 43.49+/-2.36 ml x min(-1) x mm Hg(-1), p<0.01, and 39.37+/-2.16 vs 42.99+/-2.38 ml x min(-1) x mm Hg(-1), p<0.02, for C-R and C, respectively) and 2) there were no DLCO decreases in post-trial compared with pre-trial measurement in R-R and R. CONCLUSIONS: We concluded that cycling exercise in itself seems to increase the immediate post-exercise DLCO impairment.

The effect of multi-cycle-run blocks on pulmonary function in triathletes.

BACKGROUND: This study was designed to determined the pulmonary responses elicited by multi-cycle-run exercise in triathletes and to compare them to those elicited during a simple cycle-run succession. METHODS: Twelve male triathletes underwent three successive laboratory trials: 1) an incremental cycle test, 2) 30 min of cycling followed by 20 min of running (C-R), and 3) five repeated bouts of 6 min of cycling and 4 min of running (X-CR). Before and 10 minutes after the third and fourth trials, the triathletes underwent lung function testing, especially spirometry and diffusing capacity testing for carbon monoxide (DL(CO)). During all trials, ventilatory data were collected every minute using an automated breath-by-breath system. RESULTS: The results showed that: 1) the cardiorespiratory responses observed during running were greater in the X-CR trial for VE/VCO2 and HR, 2) DL(CO) and DL(CO)/VA were significantly reduced after both trials, and 3) there were no significant changes in pulmonary volumes. CONCLUSIONS: We concluded that 1) the multi-block trial elicited greater cardioventilatory responses than simple the cycle-run succession and 2) multi-block seems a good method to stimulate the specific adaptations required for the cycle-run succession, and particularly for the cycle-run transition. In any case, the efficacy of the multi-block model needs to be more thoroughly evaluated over the course of a longer-term training programme.