Ultrasonographic reliability and repeatability of simultaneous bilateral assessment of diaphragm muscle thickness during normal breathing

Background

The diaphragm is considered the main muscle involved in breathing and also linked to trunk stabilization functions. Up to date, rehabilitative ultrasound imaging (RUSI) has been the most used technique to evaluate unilaterally the transcostal diaphragm thickness. Nevertheless, the inspiratory activity of both hemi-diaphragms is bilaterally performed at the same time, and its simultaneous evaluation with a thoracic orthosis could improve its assessment as well as its re-education with visual biofeedback of both hemi-diaphragms at the same time. The purpose was to evaluate the reliability and repeatability of simultaneous thickness measurements of both hemi-diaphragms bilaterally during normal breathing using a thoracic orthosis that allowed bilateral fixation of both right and left ultrasound probes.

Methods

The study was conducted in 46 healthy subjects, whose diaphragm thickness was measured bilaterally and simultaneously in the anterior axillary line during relaxed breathing with a designed thoracic orthosis and 2 ultrasound tools. Intra-examiner (same examiner), inter-examiner (2 examiners), intra-session (1 hour) and inter-session (1 week) reliability and repeatability between each pair of measurements of diaphragm muscle thickness were analyzed during normal breathing.

Results

Reliability and repeatability for intra-session evaluations using the thoracic orthosis were excellent to evaluate simultaneous thickness of both hemi-diaphragms by bilateral probes fixation (intraclass correlation coefficient =0.919-0.997; standard error of measurement =0.002-0.007 cm; minimum detectable change =0.006-0.020 cm), without systematic errors (P>0.05) between each pair of measurements. Nevertheless, inter-session evaluations varied from good to excellent using the bilateral probes fixation (intraclass correlation coefficient =0.614-0.984; standard error of measurement =0.006-0.028 cm; minimum detectable change =0.017-0.079 cm), although some systematic errors were presented (P<0.05).

Conclusions

Good to excellent reliability and repeatability was shown for simultaneous thickness measurements of both hemi-diaphragms bilaterally during normal breathing. Despite systematic errors were presented for some inter-examiner assessments, the use of the thoracic orthosis that allowed bilateral fixation of ultrasound probes could be recommended for simultaneous hemi-diaphragms breathing re-education by visual biofeedback.

Impact and control of the COVID pandemic in an elite sports club: Real Madrid

The incidence and risk factors for poor outcome in patients with COVID are well known, as are the protective measures in high-risk populations. In contrast, the epidemiological and clinical behavior of this disease in the population of elite athletes who are the paradigm of good health is poorly understood. Data on COVID in athletes are scarce and have focused preferentially on the consequences on sports performance of confinement measures and on the pathophysiological risks of infected athletes. Real Madrid is a large elite sports institution with facilities in the City of Madrid where 600 athletes train daily. The incidence of COVID during a study period of 671 days of observation in athletes, professional or amateur, working in the institution has been 0,74 per 1,000 days of exposure. The disease has been asymptomatic or oligosymptomatic in all athletes and did not require any hospital admissions. The different teams did not have to suspend any of its sportive commitments for COVID during the study period and there was no evidence of outbreaks of internal transmission between members of the different teams.

Low Intensity Respiratory Muscle Training in COVID-19 Patients after Invasive Mechanical Ventilation: A Retrospective Case-Series Study

Worldwide, healthcare systems had to respond to an exponential increase in COVID-19 patients with a noteworthy increment in intensive care units (ICU) admissions and invasive mechanical ventilation (IMV). The aim was to determine low intensity respiratory muscle training (RMT) effects in COVID-19 patients upon medical discharge and after an ICU stay with IMV. A retrospective case-series study was performed. Forty COVID-19 patients were enrolled and divided into twenty participants who received IMV during ICU stay (IMV group) and 20 participants who did not receive IMV nor an ICU stay (non-IMV group). Maximal expiratory pressure (PEmax), maximal inspiratory pressure (PImax), COPD assessment test (CAT) and Medical Research Council (MRC) dyspnea scale were collected at baseline and after 12 weeks of low intensity RMT. A greater MRC dyspnea score and lower PImax were shown at baseline in the IMV group versus the non-IMV group (p < 0.01). RMT effects on the total sample improved all outcome measurements (p < 0.05; d = 0.38−0.98). Intragroup comparisons after RMT improved PImax, CAT and MRC scores in the IMV group (p = 0.001; d = 0.94−1.09), but not for PImax in the non-IMV group (p > 0.05). Between-groups comparison after RMT only showed MRC dyspnea improvements (p = 0.020; d = 0.74) in the IMV group versus non-IMV group. Furthermore, PImax decrease was only predicted by the IMV presence (R2 = 0.378). Low intensity RMT may improve respiratory muscle strength, health related quality of life and dyspnea in COVID-19 patients. Especially, low intensity RMT could improve dyspnea level and maybe PImax in COVID-19 patients who received IMV in ICU.

Exercise Physiology at "Conversational Level" Is Not Impaired in Healthy Young Subjects Wearing Masks or Respirators

OBJECTIVE

The aim of this study was to evaluate the effects of the use of both surgical masks and FFP2 respirators on the inspiratory muscle strength, metabolic parameters, heart rate, subjective perceived exertion, and dyspnea perception, before and during 30 min stable load exercise at "conversational level".

METHODS

A randomized cross-over study was carried out. Nineteen healthy adults completed 3 conditions (without a mask, with a surgical mask or an FFP2 respirator) during a 30-min steady-state test at the lactate threshold intensity. Inspiratory muscle strength was measured before and after the test, and metabolic parameters, heart rate, subjective perceived exertion, and dyspnea perception were collected at baseline, during, and after the test.

RESULTS

There was a significant reduction in inspiratory muscle strength after the 30-min test in all conditions (control: 6.26 mm Hg, p < 0.5; surgical mask: 8.55 mm Hg, p < 0.01; FFP2 respirator: 12.42 mm Hg, p < 0.001), but without significant differences between them (p = 0.283). Data showed a statistically significant effect for time, but did not show a statistically significant interaction between condition and time for heart rate (p = 0.674), oxygen saturation (p = 0.297), blood lactate level (p = 0.991), rating perceived exertion (p = 0.734) and dyspnea (p = 0.532) comparisons.

CONCLUSIONS

The present study findings suggested that inspiratory muscle strength and physiological parameters during "conversational level" exercise were not impaired under wearing masks in healthy, nonsmoking young adults.

The Main Role of Diaphragm Muscle as a Mechanism of Hypopressive Abdominal Gymnastics to Improve Non-Specific Chronic Low Back Pain: A Randomized Controlled Trial

Background: Chronic low back pain (LBP) has been stated as one of the main health concerns in the XXI century due to its high incidence. Objective: The objective of this study was to determine the effects of an 8-week program of hypopressive abdominal gymnastics (HAG) on inspiratory muscle strength, diaphragm thickness, disability and pain in patients suffering from non-specific chronic LBP. Methods: A total of 40 patients with chronic LBP were randomly divided into two groups. The experimental group carried out an 8-week supervised program of HAG (two sessions/week), whereas the control group did not receive any treatment. Outcomes were measured before and after the intervention, comprising diaphragm thickness during relaxed respiratory activity, maximal inspiratory pressure (PI_max), pain intensity (NRS), pressure pain threshold and responses to four questionnaires: Physical Activity Questionnaire (PAQ), Roland–Morris Disability Questionnaire (RMQ), Central Sensitization Inventory (CSI) and Tampa Scale of Kinesiophobia-11 Items (TSK-11). Results: Statistically significant differences (p < 0.05) were observed for greater thickness of the left and right hemi-diaphragms at inspiration, as well as higher PI_max and decreased NRS, CSI and RMQ scores in the intervention group. After treatment, the increases in the thickness of the left and right hemi-diaphragms at inspiration and PI_max, as well as the decrease in the NRS and RMQ scores, were only predicted by the proposed intervention (R² = 0.118–0.552). Conclusions: An 8-week HAG intervention seemed to show beneficial effects and predicted an increase in diaphragm thickness and strength during inspiration, as well as a reduction in pain intensity, central sensitization and disability, in patients suffering from chronic non-specific LBP with respect to non-intervention.

The QardioArm App in the Assessment of Blood Pressure and Heart Rate: Reliability and Validity Study

Background

Self-measurement of blood pressure is a priority strategy for managing blood pressure.

Objective

The aim of this study was to evaluate the reliability and validity of blood pressure and heart rate following the European Society of Hypertension’s international validation protocol, as measured with the QardioArm, a fully automatic, noninvasive wireless blood pressure monitor and mobile app.

Methods

A total of 100 healthy volunteers older than 25 years from the general population of Ciudad Real, Spain, participated in a test-retest validation study with two measurement sessions separated by 5 to 7 days. In each measurement session, seven systolic blood pressure, diastolic blood pressure, and heart rate assessments were taken, alternating between the two devices. The test device was the QardioArm and the previously validated criterion device was the Omron M3. Sessions took place at a single study site with an evaluation room that was maintained at an appropriate temperature and kept free from noises and distractions.

Results

The QardioArm displayed very consistent readings both within and across sessions (intraclass correlation coefficients=0.80-0.95, standard errors of measurement=2.5-5.4). The QardioArm measurements corresponded closely to those from the criterion device (r>.96) and mean values for the two devices were nearly identical. The QardioArm easily passed all validation standards set by the European Society of Hypertension International Protocol.

Conclusions

The QardioArm mobile app has validity and it can be used free of major measurement error.

Upper extremity deep vein thrombosis in a triathlete: Again intense endurance exercise as a thrombogenic risk

Triathlon followers increase each year and long-distance events have seen major growth worldwide. In the cycling phase, athletes must maintain an aerodynamic posture on the bike for long periods of time. We report a case of a 38-year-old triathlete with symptoms of an axillary vein thrombosis 48h after a long triathlon competition. After 3days of hospitalization with a treatment consisted on enoxaparin anticoagulant and acenocumarol, the patient was discharged with instructions to continue treatment under home hospitalization with acetaminophen. Four weeks after the process, the patient was asymptomatic and the diameter of his arm was near normality. Due to the growing popularity of events based on endurance exercise, it is necessary more research to determine the etiopathogeny of deep venous thrombosis in athletes.

Lactate minimum test during incremental running after a submaximal cycling exercise: a novel test with training applications for triathletes

AIM

The purpose of the present study was to determine whether running speed determined in a lactate minimum test (lactate minimum intensity, LMI) during a treadmill incremental exercise performed just after submaximal cycling corresponds to the speed of a respiratory exchange ratio of 1.00 (RER-1) and, by extension, to the maximal lactate steady state (MLSS) previously obtained in a standard incremental exercise test.

METHODS

Eighteen moderately trained triathletes (15 men, 3 women) underwent two exercise sessions 72 h apart in random order: 1) a standard incremental treadmill test to identify the speed corresponding to RER-1, and 2) a submaximal exercise test on a bicycle-ergometer to obtain the LT (lactate threshold) followed by the incremental portion of the lactate minimum test on the treadmill.

RESULTS

No significant differences were detected between running speed and heart rate at RER-1 and LMI (14.44±1.24 vs. 14.11±1.36 km·h-1 and 166.38±9.30 vs. 169.55±8.97 beats·min-1, respectively). Moreover, 95% of the differences between the results of the two incremental tests for running speed and heart rate were within the limits of agreement.

CONCLUSION

These findings suggest the possibility of obtaining a valid physiological profile of a triathlete using a single test to assess the level of training in both cycling and running.

Impact of a physical activity program on cerebral vasoreactivity in sedentary elderly people

AIM

The aim of the present study was to determine the effect of a physical activity program on the hemodynamic response of the brain (vasoreactivity) in elderly people.

METHODS

Eighteen men and 25 women (aged 62-67 years) were randomly assigned to an experimental (EXP, N.=22, 12 women) and a control (CON, N.=21, 13 women) group. Subjects in EXP group were required to complete a 7-month program based on aerobic training (3-4 sessions/weekd, 50 min/session, 3-4 sessions/week, at 70% maximum heart rate). Transcranial Doppler ultrasound was used to examine the cerebral blood flow response to hypercapnic and hypocapnic stimuli. We also determined blood pressure, total serum cholesterol, HDL and LDL cholesterol, and triglycerides, and conducted an aerobic capacity test (the 2.4-Km walking test). RESULTS.Brain vasomotor reactivity improved in the EXP group, reflected by a higher blood flow velocity in the middle cerebral artery (MCA) in both cerebral hemispheres in response to hypercapnia (induced by breath holding) (P<0.05). Subjects in EXP group also improved the cardiovascular profile aerobic physical condition (P<0.001) in terms of reduced arterial pressure, total cholesterol and triglyceride levels.

CONCLUSION

Our findings indicate that cerebral vasoreactivity in elderly may be improved by undertaking an aerobic exercise program.

Plantar pressures in children with and without sever's disease

BACKGROUND

a case-control study was conducted to compare static plantar pressures and distribution of body weight across the two lower limbs, as well as the prevalence of gastrocnemius soleus equinus, in children with and without calcaneal apophysitis (Sever's disease).

METHODS

the participants were 54 boys enrolled in a soccer academy, of which eight were lost to follow-up. Twenty-two boys with unilateral Sever's disease comprised the Sever's disease group and 24 healthy boys constituted a control group. Plantar pressure data were collected using pedobarography, and gastrocnemius soleus equinus was assessed.

RESULTS

peak pressure and percentage of body weight supported were significantly higher in the symptomatic feet of the Sever's disease group than in the asymptomatic feet of the Sever's disease group and the control group. Every child in the Sever's disease group had bilateral gastrocnemius equinus, while nearly all children in the control group had no equinus.

CONCLUSIONS

high plantar foot pressures are associated with Sever's disease, although it is unclear whether they are a predisposing factor or a result of the condition. Gastrocnemius equinus may be a predisposing factor for Sever's disease. Further research is needed to identify other factors involved in the disease and to better understand the factors that contribute to abnormal distribution of body weight in the lower limbs.

Effects of inspiratory muscle training on exercise capacity and spontaneous physical activity in elderly subjects: a randomized controlled pilot trial

Inspiratory muscle training (IMT) has been shown to improve exercise capacity in diseased populations. We chose to examine the effects of eight weeks of IMT on exercise capacity and spontaneous physical activity in elderly individuals. Eighteen moderately active elderly subjects (68.1 +/- 6.8 years [mean +/- SD]; range 58 - 78 years) were randomly assigned to either an experimental group (n = 9) or a control group (n = 9) in a double-blind manner. All subjects underwent inspiratory muscle testing, treadmill exercise testing and a four-day measurement period of spontaneous physical activity (using accelerometry) both pre- and post-intervention. The experimental group underwent eight weeks of incremental IMT using a pressure threshold device, while the control group underwent sham training using identical devices. After IMT training, inspiratory muscle strength (mean + 21.5 cm H (2)O; 95 % CI: 9.3, 33.7; p = 0.002), V.O (2peak) (+ 2.8 ml x min (-1) x kg (-1); 95 % CI: 0.5, 5.2; p = 0.022), time to exhaustion during a fixed workload treadmill test (+ 7.1 min; 95 % CI: 1.8, 2.4; p = 0.013) and time engaged in moderate-to-vigorous physical activity (+ 59 min; 95 % CI: 15, 78; p = 0.008) improved. Except for a decline in moderate-to-vigorous physical activity, no significant changes were seen in the control group. Therefore, IMT may be a useful technique for positively influencing exercise capacity and physical activity in elderly individuals.

Frequency of the V·O2max Plateau Phenomenon in World-Class Cyclists

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

Is there an association between ACE and CKMM polymorphisms and cycling performance status during 3-week races?

In this paper, we examine the association between polymorphisms of the angiotensin-converting enzyme (ACE) and muscle-specific creatine kinase (CKMM) genes, and the actual performance status observed in professional cyclists capable of completing a classic tour stage race such as the Giro d'Italia, Tour de France, or Vuelta a España. To accomplish this, we compared the frequencies of the ACE and CKMM genotypes/alleles in 50 top-level Spanish professional cyclists that have completed at least one of these events to 119 sedentary controls, and 27 elite (Olympic-class) Spanish runners. The genetic polymorphism at the CK-MM locus was detected with the NcoI restriction endonuclease. The results of our study showed that the proportion of the DD genotype was higher in cyclists (50.0 %) than in the other two groups (p<0.05), the proportion of the ID genotype was higher in controls (46.2 %) than in the other two groups (p<0.05), and the proportion of the II genotype was higher in runners (40.7 %) than in the other two groups (p<0.05). The proportion of the D allele was higher in both cyclists (65.0 %) and controls (57.6 %) than in runners (46.3 %) (p<0.001), whereas the proportion of the I allele was higher in runners than in the other two groups (p<0.001). No statistical differences were found for CKK-MM- NcoI. We conclude that in top-level professional cyclists capable of completing a classic 3-wk tour race, the frequency distribution of the D allele and the DD genotype seems to be higher than in other endurance athletes such as elite runners (in whom the I allele is especially frequent).

Which laboratory variable is related with time trial performance time in the Tour de France?

OBJECTIVE

To investigate the relationship between several physiological variables that can be easily obtained during cycle ergometer gradual testing (for example, peak power output (W(peak)), Vo(2max), or ventilatory threshold (VT)) and actual (>50 km) time trials (TT) time performance during the Tour de France.

METHODS

We collected data in professional cyclists from the first TT of the 1998 Tour de France (TT1, 58 km distance; n = 6 cyclists) and the first (TT2, 56.5 km; n = 5) and second TT of the 1999 Tour de France (TT3, 57 km; n = 5).

RESULTS

A negative relationship was found between power output (W) at VT (VT(Watt)) and TT final time (s) in TT1 (r = -0.864; p = 0.026; standard error of estimate (SEE) of 73 s; and 95% confidence limits (95% CL) -0.98; -0.18), TT2 (r = -0.77; p = 0.27; SEE of 139 s; and 95% CL -0.98; 0.35), and TT3 (r = -0.923; p = 0.025; SEE of 94 s; and 95% CL -1.00; -0.22).

CONCLUSIONS

Actual performance in long TT during the Tour de France (>50 km distance, performed after at least 1-2 weeks of continuous competition), in which some cumulative fatigue inevitably occurs, is related, at least in part, to the power output that elicits the VT. No other routine physiological variable (for example, Vo(2max) or W(peak)) is related to performance in this type of event.

Relation between physical exertion and heart rate variability characteristics in professional cyclists during the Tour of Spain

BACKGROUND

Continued exposure to prolonged periods of intense exercise may unfavourably alter neuroendocrine, neuromuscular, and cardiovascular function.

OBJECTIVE

To examine the relation between quantifiable levels of exertion (TRIMPS) and resting heart rate (HR) and resting supine heart rate variability (HRV) in professional cyclists during a three week stage race.

METHOD

Eight professional male cyclists (mean (SEM) age 27 (1) years, body mass 65.5 (2.3) kg, and maximum rate of oxygen consumption (VO(2)max) 75.6 (2.2) ml/kg/min) riding in the 2001 Vuelta a España were examined for resting HR and HRV on the mornings of day 0 (baseline), day 10 (first rest day), and day 17 (second rest day). The rest days followed stages 1-9 and 10-15 respectively. HR was recorded during each race stage, and total HR time was categorised into a modified, three phase TRIMPS schema. These phases were based on standardised physiological laboratory values obtained during previous VO(2)max testing, where HR time in each phase (phase I = light intensity and less than ventilatory threshold (VT; approximately 70% VO(2)max); phase II = moderate intensity between VT and respiratory compensation point (RCP; approximately 90% VO(2)max); phase III = high intensity (>RCP)) was multiplied by exertional factors of 1, 2, and 3 respectively.

RESULTS

Multivariate analysis of variance showed that total TRIMPS for race stages 1-9 (2466 (90)) were greater than for stages 10-15 (2055 (65)) (p<0.0002). However, TRIMPS/day were less for stages 1-9 (274 (10)) than for stages 10-15 (343 (11)) (p<0.01). Despite a trend to decline, no difference in supine resting HR was found between day 0 (53.2 (1.8) beats/min), day 10 (49.0 (2.8) beats/min), and day 17 (48.0 (2.6) beats/min) (p = 0.21). Whereas no significant group mean changes in HR or HRV indices were noted during the course of the race, significant inverse Pearson product-moment correlations were observed between all HRV indices relative to total TRIMPS and TRIMPS/day accumulated in race stages 10-15. Total TRIMPS correlated with square root of mean squared differences of successive RR intervals (r = -0.93; p<0.001), standard deviation of the RR intervals (r = -0.94; p<0.001), log normalised total power (r = -0.97; p<0.001), log normalised low frequency power (r = -0.79; p<0.02), and log normalised high frequency power (r = -0.94; p<0.001).

CONCLUSION

HRV may be strongly affected by chronic exposure to heavy exertion. Training volume and intensity are necessary to delineate the degree of these alterations.

Mutations in the hereditary haemochromatosis gene HFE in professional endurance athletes

BACKGROUND

Hereditary haemochromatosis, a disease that affects iron metabolism, progresses with a greater or lesser tendency to induce iron overload, possibly leading to severe organ dysfunction. Most elite endurance athletes take iron supplements during their active sporting life, which could aggravate this condition.

OBJECTIVE

To determine the prevalence and discuss potential clinical implications of mutations of HFE (the gene responsible for hereditary haemochromatosis) in endurance athletes.

METHODS

Basal concentrations of iron, ferritin, and transferrin and transferrin saturation were determined in the period before competition in 65 highly trained athletes. Possible mutations in the HFE gene were evaluated in each subject by extracting genomic DNA from peripheral blood. The restriction enzymes SnaBI and BclI were used to detect the mutations 845G-->A (C282Y) and 187C-->G (H63D).

RESULTS

Our findings indicate a high prevalence of HFE gene mutations in this population (49.2%) compared with sedentary controls (33.5%). No association was detected in the athletes between mutations and blood iron markers.

CONCLUSIONS

The findings support the need to assess regularly iron stores in elite endurance athletes.

Giro, Tour, and Vuelta in the same season

The exercise volume and intensity are reported of a male professional cyclist (age 30; VO2max 75.0 ml/kg/min) who successfully completed the 2001 Giro d'Italia (May), Tour de France (July), and Vuelta a España (September). The total exercise time during the Giro, Tour, and Vuelta was 90 hours 44 minutes (5444 minutes), 88 hours 23 minutes (5303 minutes), and 72 hours 59 minutes (4379 minutes) respectively. Heart rate telemetry during the races allowed the exercise intensity to be classified into three phases: I, below the first ventilatory threshold (VT1); II, between VT1 and the second ventilatory threshold (VT2); III, above VT2. Compared with the Giro and Tour, the lower exercise volume of the Vuelta (about 20% less total time) was compensated for by a considerably lower and higher contribution of phases I and III respectively. As a result, the total load (volume x intensity) in the three races was comparable.

Effects of electrical stimulation on VO2 kinetics and delta efficiency in healthy young men

OBJECTIVE

To determine the effects of electrical stimulation (ES) on oxygen uptake (VO(2)) kinetics and delta efficiency (DE) during gradual exercise. The hypothesis was that ES would attenuate the VO(2)-workload relation and improve DE.

METHODS

Fifteen healthy, untrained men (mean (SD) age 22 (5) years) were selected. Ten were electrostimulated on both quadriceps muscles with a frequency of 45-60 Hz, with 12 seconds of stimulation followed by eight seconds recovery for a total of 30 minutes a day, three days a week for six weeks. The remaining five subjects were assigned to a control group. A standardised exercise test on a cycle ergometer (ramp protocol, workload increases of 20 W/min) was performed by each subject before and after the experimental period. The slope of the VO(2)-power output (W) relation (deltaVO(2)/deltaW) and DE were calculated in each subject at moderate to high intensities (above the ventilatory threshold-that is, from 50-60% to 100% VO(2)max).

RESULTS

The mean (SEM) values for deltaVO(2)/deltaW and DE had significantly decreased and increased respectively after the six week ES programme (p<0.05; 9.8 (0.2) v 8.6 (0.5) ml O(2)/W/min respectively and 27.7 (0.9) v 31.5 (1.4)% respectively).

CONCLUSIONS

ES could be used as a supplementary tool to improve two of the main determinants of endurance capacity, namely VO(2) kinetics and work efficiency.

The response of sexual and stress hormones of male pro-cyclists during continuous intense competition

The aim of this study was to compare hormonal changes in plasma total testosterone (T), cortisol (C), luteinizing hormone (LH), follicle-stimulating hormone (FSH) and prolactin (P) in two world-class teams, both consisting of 9 top male pro-cyclists, during a real sports situation (the 1998 "Vuelta a España", a 3-week multi-stage international cycling competition). Venous blood samples were taken the day before the race (S0), after 1 week (S1), after 2 weeks (S2) and at the end of the race (S3). The S0 T level was significantly lower in the team with more racing days in the previous month. There was a significant basal T decrease (p < 0.05) during the race in comparison with the initial value, in spite of the difference in S0 T level between teams. However, there was no difference between teams in the mean decrease in T level. C decreased significantly between S0 and S1 and between S1 and S2, but not between S2 and S3. There were no differences in P concentration between teams or throughout the study, except for a significant increase between S2 and S3. There were no initial differences in LH nor FSH concentration between the teams, nor at any of the study follow-up times. We conclude that in professional top-level athletes S0 T values depend on the number of competition days of the previous month. We observed a similar decrease in the T levels in both teams, independent of the absolute S0 values. In both teams C decreased during long-lasting cycling competition.

Thyroid hormone levels during a 3-week professional road cycling competition

AIMS

The aim of this investigation was to examine the thyroid hormone levels of professional cyclists during a 3-week stage competition (Vuelta a España 1998).

METHODS

The study population was made up of 16 male cyclists from two world-leading professional teams. Four blood samples were drawn (between 07:00 and 09:00 a.m.) from each participant before and at the end of the 1st, 2nd and 3rd weeks of competition. 3,5,3'(-Triiodothyronine (T(3)), free T(3) (FT(3)), thyroxine (T(4)), free T(4) (FT(4)) and thyroid-stimulating hormone (TSH) were determined in each blood sample by radioimmunoassay.

RESULTS

Serum T(4), FT(4) and FT(3) levels showed a significant increase (p < 0.05) by the last week of competition while concentrations of TSH and T(3) remained unchanged.

CONCLUSION

In conclusion, 3 weeks of competition provokes changes in basal thyroid hormone concentrations in professional road cyclists.

Lactic acidosis, potassium, and the heart rate deflection point in professional road cyclists

OBJECTIVE

To determine the influence of lactic acidosis, the Bohr effect, and exercise induced hyperkalaemia on the occurrence of the heart rate deflection point (HRDP) in elite (professional) cyclists.

METHODS

Sixteen professional male road cyclists (mean (SD) age 26 (1) years) performed a ramp test on a cycle ergometer (workload increases of 5 W/12 s, averaging 25 W/min). Heart rate (HR), gas exchange parameters, and blood variables (lactate, pH, P(50) of the oxyhaemoglobin dissociation curve, and K(+)) were measured during the tests.

RESULTS

A HRDP was shown in 56% of subjects at about 88% of their maximal HR (HRDP group; n = 9) but was linear in the rest (No-HRDP group; n = 7). In the HRDP group, the slope of the HR-workload regression line above the HRDP correlated inversely with levels of K(+) at the maximal power output (r = -0.67; p<0.05).

CONCLUSIONS

The HRDP phenomenon is associated, at least partly, with exercise induced hyperkalaemia.

Effects of transcutaneous short-term electrical stimulation on M. vastus lateralis characteristics of healthy young men

Fifteen healthy, untrained male subjects (mean age +/- SD, 22 +/- 5 years) were used to examine the plasticity of myosin heavy chain phenotype, size, oxidative capacity and capillarization of skeletal muscle fibre types with short-term electrical stimulation (ES). Ten subjects were electro-stimulated on both quadriceps muscles with a frequency of 45-60 Hz, with 12 s of stimulation followed by 8 s of recovery for a total of 30 min per day, 3 days per week for 6 weeks. The remaining five subjects served as controls. Two vastus lateralis muscle biopsy samples were removed from each subject before (week 0) and after (week 6) ES training. A standardized exercise test on a cycle ergometer was performed by each subject before and after the experimental period and several indicators of whole-body aerobic capacity were estimated. The so-called electromyographic threshold was also determined during the tests. Muscle biopsy samples were analysed by electrophoresis, immunohistochemistry and quantitative histochemistry. Myosin heavy chain (MHC) composition, muscle fibre type distribution, fibre areas, oxidative capacity and capillaries of each fibre type were estimated. Muscular changes with ES revealed an increase of fibres expressing MHC-IIA, and a decrease of fibres expressing MHC-IIX and MHC-I, as well as an increase of the oxidative capacity and mean number of capillaries of fast-twitch (type II) fibres with minimal muscle fibre hypertrophy. These adaptations seem related to a bi-directional transformation from both MHC isoforms I and IIX towards the MHC-IIA isoform. The aerobic performance and electromyographic variables at the whole-body level were not altered by ES. These results indicate that the particular short-term ES training protocol tested in the present study induces significant adaptations in histochemical and metabolic machineries of human skeletal muscle. The results also offer new perspectives for realistic applications of ES in various clinical situations and sport training.

Plasma oxytocin during intense exercise in professional cyclists

AIMS

This study was designed to explore the plasma oxytocin (OT) response to exercise until exhaustion in trained male cyclists.

METHODS

Twelve professional cyclists (EXP group; age: 26 +/- 2 years; VO(2)max: 4,804 +/- 549 ml) and 10 sedentary young men (CONT group; age: 23 +/- 2 years; VO(2)max: 3,146 +/- 602 ml) performed a maximal incremental exercise test on a cycle ergometer. Evaluation was made of the oxygen uptake (VO(2)) and concentrations of blood lactate and plasma OT immediately before, during and immediately after the tests, respectively.

RESULTS

Significant increases (p < 0.01) related to exercise were recorded in VO(2) and lactate concentration within each group, while no such changes were observed in OT levels. OT values, on the other hand, were significantly lower (p < 0.01) in EXP than in CONT throughout the tests.

CONCLUSION

It was concluded that plasma OT shows no response to graded exercise until exhaustion in professional cyclists.

Hormone levels of world class cyclists during the Tour of Spain stage race

OBJECTIVES

To evaluate the hormonal response to strenuous endurance exercise performed by elite athletes.

METHODS

Nine professional cyclists (mean (SD) age 28 (1) years; mean (SD) VO(2)MAX 75.3 (2.3) ml/kg/min) who participated in a three week tour race (Vuelta a España 1999) were selected as subjects. Morning urinary levels of 6-sulphatoxymelatonin (aMT6s) and morning serum levels of testosterone, follicle stimulating (FSH), luteinising hormone (LH), and cortisol were measured in each subject at t(0) (before the competition), t(1) (end of first week), t(2) (end of second week), and t(3) (end of third week). Urine samples of aMT6s were also evaluated in the evening at t(0), t(1), t(2), and t(3).

RESULTS

Mean urinary aMT6s levels had increased significantly (p<0.01) during the day after each stage (1091 (33) v 683 (68) ng/ml at t(1); 955 (19) v 473 (53) ng/ml at t(2); 647 (61) v 337 (47) ng/ml at t(3)). Both morning and evening aMT6s levels decreased significantly during the study. A similar pattern was observed for morning serum levels of cortisol and testosterone.

CONCLUSIONS

The results suggest that the basal activity of the pineal gland, adrenal glands, and testis may be decreased after consecutive days of intense, long term exercise.

Effects of an endurance cycling competition on resting serum insulin-like growth factor I (IGF-I) and its binding proteins IGFBP-1 and IGFBP-3

OBJECTIVES

To determine whether consecutive bouts of intense endurance exercise over a three week period alters serum concentrations of insulin-like growth factor I (IGF-I) and/or its binding proteins.

METHODS

Seventeen professional cyclists (mean (SEM) VO(2)MAX, 74.7 (2.1) ml/kg/min; age, 27 (1) years) competing in a three week tour race were selected as subjects. Blood samples were collected at each of the following time points: t(0) (control, before the start of competition), t(1) (end of first week), and t(3) (end of third week). Serum levels of both total and free IGF-I and IGF binding proteins 1 and 3 (IGFBP-1 and IGFBP-3) were measured in each of the samples. Cortisol levels were measured in nine subjects.

RESULTS

A significant (p<0.01) increase was found in total IGF-I and IGFBP-1 at both t(1) and t(3) compared with t(o) (IGF-I: 110.9 (17.7), 186.8 (12.0), 196.9 (14.7) ng/ml at t(0), t(1), and t(3) respectively; IGFBP-1: 54.6 (6.6), 80.6 (8.0), and 89.2 (7.9) ng/ml at t(0), t(1), and t(3) respectively). A significant (p<0.01) decrease was noted in free IGF-I at t(3) compared with both t(o) and t(1) (t(0): 0.9 (0.1) ng/ml; t(1): 0.9 (0.1) ng/ml; t(3): 0.7 (0.1) ng/ml); in contrast, IGFBP-3 levels remained stable throughout the race.

CONCLUSIONS

It would appear that the increase in circulating levels of both IGF-I and its binding protein IGFBP-1 is a short term (one week) endocrine adaptation to endurance exercise. After three weeks of training, total IGF-I and IGFBP-1 remained stable, whereas free IGF-I fell below starting levels.

Physiology of professional road cycling

Professional road cycling is an extreme endurance sport. Approximately 30000 to 35000 km are cycled each year in training and competition and some races, such as the Tour de France last 21 days (approximately 100 hours of competition) during which professional cyclists (PC) must cover >3500 km. In some phases of such a demanding sport, on the other hand, exercise intensity is surprisingly high, since PC must complete prolonged periods of exercise (i.e. time trials, high mountain ascents) at high percentages (approximately 90%) of maximal oxygen uptake (VO2max) [above the anaerobic threshold (AT)]. Although numerous studies have analysed the physiological responses of elite, amateur level road cyclists during the last 2 decades, their findings might not be directly extrapolated to professional cycling. Several studies have recently shown that PC exhibit some remarkable physiological responses and adaptations such as: an efficient respiratory system (i.e. lack of 'tachypnoeic shift' at high exercise intensities); a considerable reliance on fat metabolism even at high power outputs; or several neuromuscular adaptations (i.e. a great resistance to fatigue of slow motor units). This article extensively reviews the different responses and adaptations (cardiopulmonary system, metabolism, neuromuscular factors or endocrine system) to this sport. A special emphasis is placed on the evaluation of performance both in the laboratory (i.e. the controversial Conconi test, distinction between climbing and time trial ability, etc.) and during actual competitions such as the Tour de France.

Preferred pedalling cadence in professional cycling

PURPOSE

The aim of this investigation was to evaluate the preferred cycling cadence of professional riders during competition.

METHODS

We measured the cadence of seven professional cyclists (28 +/- 1 yr) during 3-wk road races (Giro d'Italia, Tour de France, and Vuelta a España) involving three main competition requirements: uphill cycling (high mountain passes of approximately 15 km, or HM); individual time trials of approximately 50 km on level ground (TT); and flat, long ( approximately 190 km) group stages (F). Heart rate (HR) data were also recorded as an indicator of exercise intensity during HM, TT, and F.

RESULTS

Mean cadence was significantly lower (P < 0.01) during HM (71.0 +/- 1.4 rpm) than either F and TT (89.3 +/- 1.0 and 92.4 +/- 1.3 rpm, respectively). HR was similar during HM and TT (157 +/- 4 and 158 +/- 3 bpm) and in both cases higher (P < 0.01) than during F (124 +/- 2 bpm).

CONCLUSION

During both F and TT, professional riders spontaneously adopt higher cadences (around 90 rpm) than those previously reported in the majority of laboratory studies as being the most economical. In contrast, during HM they seem to adopt a more economical pedalling rate (approximately 70 rpm), possibly as a result of the specific demands of this competition phase.

Effects of endurance training on the breathing pattern of professional cyclists

The aim of this longitudinal study was to clarify the changes induced by endurance training on the breathing pattern of 13 professional cyclists (age+/-SD: 24+/-2 years; VO(2 max) approximately 75 ml x kg(-1) x min(-1)) during the three periods (rest, precompetition, and competition) of a sports season. Both the volume and the intensity of training were quantified during these periods. In each session (corresponding to each of the three periods) all subjects performed (1) a pulmonary function test (to measure forced vital capacity [FVC], peak expiratory flow [PEF], and maximal voluntary ventilation [MVV]), and (2) a ramp test until exhaustion on a cycle ergometer (workload increases of 25 W x min(-1)). The following variables were recorded every 100 W until the end of the tests: pulmonary ventilation (VE, in l x min(-1) BTPS), tidal volume (VT, inl BTPS), breathing frequency (f(b), in breaths x min(-1)), ventilatory equivalents for oxygen (VE x VO(2)(-1)) and carbon dioxide (VE x VCO(2)(-1)), inspiratory (TI) and expiratory (TE) times (s), ratio of TI to total respiratory duration or inspiratory "duty cycle" (TI/TTOT, and mean inspiratory flow rate (VT)/TI), in l x s(-1)). The results showed no changes in any of these variables (p>0.05) between the three periods of study, despite significant changes in training loads (i.e., increases in the volume and/or intensity of training throughout the season). These findings suggest that endurance conditioning does not alter the breathing pattern of professional cyclists during an incremental exercise test.

Thyroid hormones may influence the slow component of VO(2) in professional cyclists

We analyzed the relationship between the plasma concentrations of several hormones (testosterone [T], follicle-stimulating [FSH] and luteinizing hormone [LH], cortisol [C], 3,5,3'-triiodothyronine [T(3)], thyroxine [T(4)], and thyrotrophin [TSH]) and the magnitude of the VO(2) slow component (Delta VO(2)) in a group of nine professional road cyclists (26+/-2 years). The resting levels of the aforementioned hormones were determined before the subjects performed a 20-min cycle ergometer test at approximately 80% of VO(2 max) (or approximately 400 W). Plasma concentrations of T(3) and T(4) were inversely correlated (p<0.05) with Delta VO(2) (r=-0.72 and rr=-0.66, respectively), suggesting, at least partly, and association between thyroid basal function and the VO(2) slow component of euthyroid elite endurance athletes during constant-load intense exercise.

Homogeneity and stability studies on sodium, calcium, magnesium, and manganese in human saliva

This article reports on the homogeneity and stability of saliva samples treated and stored under different conditions. The analytes chosen for this evaluation were Na, Ca, and Mg as minor elements and Mn as the trace element. The results obtained show that when the sample was homogenized in an ultrasonic bath, a minimum volume of 0.25 mL was required to consider the sample homogeneous. The stability of the analytes depended on their concentration. The Ca and Mg content seemed to be stable for at least 1 wk when the samples were stored at room temperature, whereas the Mn content seemed to be unstable for 1 d even when the sample was stored at -20 degreesC.

Effects of endurance training on the isocapnic buffering and hypocapnic hyperventilation phases in professional cyclists

OBJECTIVES

To evaluate the changes produced in both the isocapnic buffering and hypocapnic hyperventilation (HHV) phases of professional cyclists (n = 11) in response to endurance training, and to compare the results with those of amateur cyclists (n = 11).

METHODS

Each professional cyclist performed three laboratory exercise tests to exhaustion during the active rest (autumn: November), precompetition (winter: January), and competition (spring: May) periods of the sports season. Amateur cyclists only performed one exercise test during the competition period. The isocapnic buffering and HHV ranges were calculated during each test and defined as Vo2 and power output (W).

RESULTS

No significant differences were found in the isocapnic buffering range in each of the periods of the sports season in professional cyclists. In contrast, there was a significant reduction in the HHV range (expressed in W) during both the competition (p<0.01) and precompetition(p<0.05) periods compared with the rest period. On the other hand, a longer HHV range (p<0.01) was observed in amateur cyclists than in professional cyclists (whether this was expressed in terms of Vo2 or W).

CONCLUSIONS

No change is observed in the isocapnic buffering range of professional cyclists throughout a sports season despite a considerable increase in training loads and a significant reduction in HHV range expressed in terms of power output.

The slow component of VO2 in professional cyclists

OBJECTIVES

To analyse the slow component of oxygen uptake (VO2) in professional cyclists and to determine whether this phenomenon is due to altered neuromuscular activity, as assessed by surface electromyography (EMG).

METHODS

The following variables were measured during 20 minute cycle ergometer tests performed at about 80% of VO2MAX in nine professional road cyclists (mean (SD) age 26 (2) years; VO2max 72.6 (2.2) ml/kg/min): heart rate (HR), gas exchange variables (VO2, ventilation (VE), tidal volume (VT), breathing frequency (fb), ventilatory equivalents for oxygen and carbon dioxide (VE/VO2 and VE/VCO2 respectively), respiratory exchange ratio (RER), and end tidal PO2 and PCO2 (PETO2 and PETCO2 respectively)), blood variables (lactate, pH, and [HCO3-]) and EMG data (root mean from square voltage (rms-EMG) and mean power frequency (MPF)) from the vastus lateralis muscle.

RESULTS

The mean magnitude of the slow component (from the end of the third minute to the end of exercise) was 130 (0.04) ml in 17 minutes or 7.6 ml/min. Significant increases from three minute to end of exercise values were found for the following variables: VO2 (p<0.01), HR (p<0.01), VE (p<0.05), fb (p<0.01), VE/VO2 (p<0.05), VE/VCO2 (p<0.01), PETO2 (p<0.05), and blood lactate (p<0.05). In contrast, rms-EMG and MPF showed no change (p>0.05) throughout the exercise tests.

CONCLUSIONS

A significant but small VO2 slow component was shown in professional cyclists during constant load heavy exercise. The results suggest that the primary origin of the slow component is not neuromuscular factors in these subjects, at least for exercise intensities up to 80% of VO2MAX.

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.

Physiological response to professional road cycling: climbers vs. time trialists

The purpose of this study was to identify possible physiological differences between professional cyclists who show best performance in hill climbing ("climbers") and those who excel in time trials ("time trialists"). To this end, professional, top-level climbers (C; n=8; age 26 +/- 1yr; height 176.0 +/- 2.0cm; body mass 63.6 +/- 2.2 kg) and time trialists (TT; n=6; 27 +/- 1yr; height 181.6 +/- 1.7 cm; body mass 72.3 +/- 2.3 kg) were required to perform two laboratory exercise tests on a cycle ergometer: a) a maximal exercise test (ramp protocol) and b) a constant load test of 20-min duration at approximately 80% of VO2max. Capillary blood lactate concentration and several gas exchange variables were measured during the maximal tests while determinations made during the submaximal tests also included: pH and bicarbonate concentration [HCO3-] in venous blood, and electromyographic (EMG) recordings from the vastus lateralis muscle to estimate root mean square voltage (rms-EMG) and mean power frequency (MPF). Both the maximal lactate concentration in capillary blood and VO2max were greater (p<0.05) in C than in TT (6.6 +/- 0.9 mM vs. 5.0 +/- 0.4 mM, respectively, and 78.4 +/- 3.2 ml x kg(-1) x min(-1) vs. 70.5 +/- 2.4 ml x kg(-1) x min(-1), respectively). Higher mean venous blood pH and [HCO3-] (p<0.05), rms-EMG (p<0.01) and MPF (p<0.05 at 10 and 15min of exercise and p < 0.01 at 5 and 20 min) were recorded in C throughout the submaximal tests. Our findings suggest that in top-level professional cyclists, climbing performance is mainly related to physiological factors (VO2max normalized for body mass, anaerobicl buffer capacity, motor unit recruitment) whereas time trialists tend to achieve greater absolute power outputs. It would also seem that other "technical" requirements of the sport (i. e. pedaling efficiency probably related to biomechanical factors etc.) may be associated with successful time trial performance.

Synthesis of ecteinascidin ET-743 and phthalascidin Pt-650 from cyanosafracin B

An efficient new process is described for the synthesis of ecteinascidin ET-743 (1) and phthalascidin (2), starting from readily available cyanosafracin B (3).

Metabolic and neuromuscular adaptations to endurance training in professional cyclists: a longitudinal study

The aim of this longitudinal study was to analyze the changes in several metabolic and neuromuscular variables in response to endurance training during three defined periods of a full sports season (rest, precompetition and competition). The study population was formed by thirteen professional cyclists (age +/- SEM: 24+/-1 years; mean V(O2 max) approximately 74 ml kg(-1) min(-1)). In each testing session, subjects performed a ramp test until exhaustion on a cycle ergometer (workload increases of 25 W min(-1)). The following variables were recorded every 100 W until the tests: oxygen consumption (V(O2) in l min(-1)), respiratory exchange ratio (RER in V(CO2) V(O2)(-1)) and blood lactate, pH and bicarbonate concentration [HCO3(-)]. Surface electromyography (EMG) recordings were also obtained from the vastus lateralis to determine the variables: root mean square voltage (rms-EMG) and mean power frequency (MPF). RER and lactate values both showed a decrease (p<0.05) throughout the season at exercise intensities corresponding to submaximal workloads. In contrast, no significant differences were found in mean pH or [HCO(3-)]. Finally, rms-EMG tended to increase during the season, with significant differences (p<0.05) observed mainly between the competition and rest periods at most workloads. In contrast, precompetition MPF values increased (p<0.05) with respect to resting values at most submaximal workloads but fell (p<0.05) during the competition period. Our findings suggest that endurance conditioning induces the following general adaptations in elite athletes: (1) lower circulating lactate and increased reliance on aerobic metabolism at a given submaximal intensity, and possibly (2) an enhanced recruitment of motor units in active muscles, as suggested by rms-EMG data.

The salivary amylase, lactate and electromyographic response to exercise

Twelve trained young males (age: 24 +/- 5 years) performed an incremental test to exhaustion during which capillary blood and saliva samples were obtained to determine the blood lactate (LT) and salivary amylase (T(sa)) thresholds. The root mean-square voltage of electromyographic activity (rms-EMG) of the vastus lateralis muscle was also recorded to detect the electromyographic threshold (EMG(T)). No significant difference was found between the exercise intensity corresponding to the LT, T(sa) or EMG(T).

Heart dimensions may influence the occurrence of the heart rate deflection point in highly trained cyclists

OBJECTIVES

To determine whether the heart rate (HR) response to exercise in 21 highly trained cyclists (mean (SD) age 25 (3) years) was related to their heart dimensions.

METHODS

Before performing an incremental exercise test involving a ramp protocol with workload increases of 25 W/min, each subject underwent echocardiographic evaluation of the following variables: left ventricular end diastolic internal diameter (LVIDd), left ventricular posterior wall thickness at end diastole (LVPWTd), interventricular septal wall thickness at end diastole (IVSTd), left ventricular mass index (LVMI), left atrial dimension (LAD), longitudinal left atrial (LLAD) and right atrial (LRAD) dimensions, and the ratio of early to late (E/A) diastolic flow velocity.

RESULTS

The HR response showed a deflection point (HRd) at about 85% VO2MAX in 66.7% of subjects (D group; n = 14) and was linear in 33.3% (NoD group; n = 7). Several echocardiographic variables (LVMI, LAD, LLAD, LRAD) indicative of heart dimensions were similar in each group. However, mean LPWTd (p<0.01) and IVSTd (p<0.05) values were significantly higher in the D group. Finally, no significant difference between groups was found with respect to the E/A.

CONCLUSIONS

The HR response is curvilinear during incremental exercise in a considerable number of highly trained endurance athletes-that is, top level cyclists. The departure of HR increase from linearity may predominantly occur in athletes with thicker heart walls.

Blood ammonia response during incremental and steady-state exercise in military staff

BACKGROUND

Although in the last few years it has been possible to determine blood ammonia, its application in coaching practice has not yet been fully established. This study was designed to evaluate the blood ammonia response to a laboratory incremental exercise test and three steady-state field tests.

METHODS

There were 26 military personnel who performed a submaximal and maximal exercise test on a treadmill, and a field test which included three different constant velocity stages. Gas exchange parameters were monitored throughout the maximal test. Capillary blood samples were obtained from fingertips during the submaximal and field tests for the determination of ammonia and lactate.

RESULTS

The ammonia threshold was detected in 23 subjects (88.5%) during the submaximal test. No significant differences were found between the ammonia and lactate thresholds which were shown to be significantly correlated. Blood ammonia levels showed a progressive increase during the last two stages of the field test while lactate levels remained stable at less than 4 mmol x L(-1).

CONCLUSIONS

The steady increase in blood ammonia concentration recorded in the field test suggests the possibility of using blood ammonia levels to monitor the duration of exercise although further investigation is required to explore this possibility. Moreover, the assessment of blood ammonia levels during incremental exercise protocols confirms the existence of an ammonia threshold, defined as the intensity of exercise at which ammonia shows a progressive increase.

Short-term effects of marathon running in master runners: no evidence of myocardial injury

The purpose of this investigation was to analyze the short-term effects of marathon running on serum levels of cardiac markers in a group of master runners (> 60 yrs). Ten marathoners (9 male and 1 female; 63+/-4 yrs) were enrolled in the study. All of them completed the Madrid Marathon (1998). Venous blood was drawn from each subject three times during the study (48 h before the race, immediately after the race, and 24 h post-competition) for the determination of the several biochemical markers, such as total creatine kinase catalytic activity (total CK), mass concentration of creatine kinase isoenzyme MB (CK-MB mass), and cardiac troponin I (Tnl-c). The most important finding was that in each sample (pre- or post-race) serum Tnl-c was below the commonly accepted level of 0.1 ng x m(-1) indicative of myocardial injury. Although further research is needed using more complete methodology, our results suggest that marathon running does not have an acute deleterious effect on the hearts of the elderly.

Short-term effects of marathon running: no evidence of cardiac dysfunction

PURPOSE

The purpose of this study was to analyze the short-term effects of a marathon race (Madrid Marathon) on both markers of cardiac damage and echocardiographic parameters in a group of 22 runners (17 male and 5 female; 34 +/- 5 yr; VO2max: 55.7 +/- 9.1 mL x kg(-1) x min(-1) with a wide range of fitness levels.

METHODS

Venous blood samples were collected from each subject 48 h before the race, at race finish, and 6, 24, and 48 h postexercise for the determination of myoglobin, total creatine kinase catalytic activity (total CK), mass concentration of creatine kinase isoenzyme MB (CK-MB mass), and cardiac isoforms of troponin T and I (TnT-c and TnI-c, respectively). In addition, echocardiographic parameters (M-mode two-dimensional and Doppler analysis) indicative of both left ventricular (LV) systolic and diastolic function were obtained three times from each runner: 2-5 d before the race, at race finish, and 24-36 h after exercise.

RESULTS

Except in one subject, levels of TnT-c and TnI-c were within normal limits (<0.1 ng x mL(-1)) in all the samples collected before or after the race. Overall LV systolic function was not altered by marathon running. Finally, LV diastolic function was transiently altered after the race since the ratio between peak early and late transmitral filling velocities (E/A) was significantly reduced at race finish (P < 0.01) and returned to resting levels after 24-36 h.

CONCLUSIONS

Our findings suggest that marathon running does not adversely affect the hearts of healthy individuals independently from their training status.

Determination of the maximum steady state of lactate (MLSS) in saliva: an alternative to blood lactate determination

Based on previous research which shows parallelism between the saliva and blood lactate response during incremental exercise, we hypothesized that a "maximum salivary lactate steady state" (saliva-MLSS) might exist. Thus, the aim of the present investigation was to establish 1) which lower limit for the increase in salivary lactate concentration during a constant workload (i.e., from the 10th to the 20th min) test could be used to determine the saliva-MLSS and 2) if the exercise intensity corresponding to the saliva-MLSS is identical to that evoking the (blood) MLSS. Twelve male amateur athletes of mean ( +/- SD) age 24 +/- 5 year were selected for the study. Based on the results of a previous maximal cycle ergometer test for lactate threshold (LT) determination, each subject performed consecutive constant workload tests of 20-min duration on separate days for MLSS determination. Blood and saliva (25 microl) samples were collected at 0, 10, and 20 min during the tests for lactate determination. A Student's t-test for paired data demonstrated that a salivary lactate increase of 0.8 mM corresponded to the saliva-MLSS. At this value, indeed, no significant differences were observed between the mean V(.)O(2) and W values corresponding to the MLSS and the saliva-MLSS. In conclusion, the present findings indicate that 0.8 mM is the lower limit for the increase in saliva lactate concentration during a constant load test and thus is that which might be used as a reference to determine saliva-MLSS. Furthermore, saliva-MLSS might be used as an alternative to MLSS determination in blood samples.

Analysis of the aerobic-anaerobic transition in elite cyclists during incremental exercise with the use of electromyography

OBJECTIVES

To investigate the validity and reliability of surface electromyography (EMG) as a new non-invasive determinant of the metabolic response to incremental exercise in elite cyclists. The relation between EMG activity and other more conventional methods for analysing the aerobic-anaerobic transition such as blood lactate measurements (lactate threshold (LT) and onset of blood lactate accumulation (OBLA)) and ventilatory parameters (ventilatory thresholds 1 and 2 (VT1 and VT2)) was studied.

METHODS

Twenty eight elite road cyclists (age 24 (4) years; VO2MAX 69.9 (6.4) ml/kg/min; values mean (SD)) were selected as subjects. Each of them performed a ramp protocol (starting at 0 W, with increases of 5 W every 12 seconds) on a cycle ergometer (validity study). In addition, 15 of them performed the same test twice (reliability study). During the tests, data on gas exchange and blood lactate levels were collected to determine VT1, VT2, LT, and OBLA. The root mean squares of EMG signals (rms-EMG) were recorded from both the vastus lateralis and the rectus femoris at each intensity using surface electrodes.

RESULTS

A two threshold response was detected in the rms-EMG recordings from both muscles in 90% of subjects, with two breakpoints, EMGT1 and EMGT2, at around 60-70% and 80-90% of VO2MAX respectively. The results of the reliability study showed no significant differences (p > 0.05) between mean values of EMGT1 and EMGT2 obtained in both tests. Furthermore, no significant differences (p > 0.05) existed between mean values of EMGT1, in the vastus lateralis and rectus femoris, and VT1 and LT (62.8 (14.5) and 69.0 (6.2) and 64.6 (6.4) and 68.7 (8.2)% of VO2MAX respectively), or between mean values of EMGT2, in the vastus lateralis and rectus femoris, and VT2 and OBLA (86.9 (9.0) and 88.0 (6.2) and 84.6 (6.5) and 87.7 (6.4)% of VO2MAX respectively).

CONCLUSION

rms-EMG may be a useful complementary non-invasive method for analysing the aerobic-anaerobic transition (ventilatory and lactate thresholds) in elite cyclists.

Trace elements and electrolytes in human resting mixed saliva after exercise

OBJECTIVES

Exercise is known to cause changes in the concentration of salivary components such as amylase, Na, and Cl. The aim of this investigation was to evaluate the effect of physical exercise on the levels of trace elements and electrolytes in whole (mixed) saliva.

METHODS

Forty subjects performed a maximal exercise test on a cycle ergometer. Samples of saliva were obtained before and immediately after the exercise test. Sample concentrations of Fe, Mg, Sc, Cr, Mn, Co, Cu, Zn, Se, Sr, Ag, Sb, Cs, and Hg were determined by inductively coupled plasma mass spectrometry and concentrations of Ca and Na by atomic absorption spectrometry.

RESULTS

After exercise, Mg and Na levels showed a significant increase (p < 0.05) while Mn levels fell (p < 0.05). Zn/Cu molar ratios were unaffected by exercise.

CONCLUSIONS

Intense physical exercise induced changes in the concentrations of only three (Na, Mg, and Mn) of the 16 elements analysed in the saliva samples. Further research is needed to assess the clinical implications of these findings.

Breathing pattern in highly competitive cyclists during incremental exercise

The purpose of our investigation was to analyse the breathing patterns of professional cyclists during incremental exercise from submaximal to maximal intensities. A group of 11 elite amateur male road cyclists [E, mean age 23 (SD 2) years, peak oxygen uptake (VO2peak) 73.8 (SD 5.0) ml kg(-1) min(-1)] and 14 professional male road cyclists [P, mean age 26 (SD 2) years, (VO2peak) 73.2 (SD 6.6) ml kg(-1) min(-1)] participated in this study. Each of the subjects performed an exercise test on a cycle ergometer following a ramp protocol (exercise intensity increases of 25 W x min(-1)) until the subject was exhausted. For each subject, the following parameters were recorded during the tests: oxygen consumption (VO2), carbon dioxide output (VCO2), pulmonary ventilation (VE), tidal volume (VT), breathing frequency (fb), ventilatory equivalents for oxygen (VE x VO2(-1)) and carbon dioxide (VE x VCO2(-1)), end-tidal partial pressure of oxygen and partial pressure of carbon dioxide, inspiratory (tI) and expiratory (tE) times, inspiratory duty cycle (tI/tTOT, where tTOT is the time for one respiratory cycle), and mean inspiratory flow rate (VT/tI). Mean values of VE were significantly higher in E at 300, 350 and 400 W (P < 0.05, P < 0.05 and P < 0.01, respectively); fb was also higher in E in most moderate-to-maximal intensities. On the other hand, VT showed a different pattern in both groups at near-to maximal intensities, since no plateau was observed in P. The response of tI and tE was also different. Finally, VT/tI and tI/tTOT showed a similar response in both P and E. It was concluded that the breathing pattern of the two groups differed mainly in two aspects: in the professional cyclists, VE increased at any exercise intensity as a result of increases in both VT and fb, with no evidence of tachypnoeic shift, and tE was prolonged in this group at high exercise intensities. In contrast, neither the central drive nor the timing component of respiration seem to have been significantly altered by the training demands of professional cycling.

Heart rate response to professional road cycling: the Tour de France

The aim of the present investigation was to evaluate the heart rate response of 8 professional cyclists (26+/-3 yr; 68.9+/-5.2 kg; V02max: 74.0+/-5.8 ml x kg(-1) x min(-1)) during the 3-week Tour de France as an indicator of exercise intensity. Subjects wore a heart rate telemeter during 22 competition stages and recorded data were analysed using computer software. Two reference heart rates (corresponding to the first and second ventilatory thresholds or VT1 and VT2) were used to establish three levels of exercise intensity defined as phases I (<VT1), II (VT1 -VT2) and III (<VT2). The average total time spent by each subject in each of the 3 phases respectively was approximately 71, 23 and 8 h. The relative contributions of each phase were 70, 23 and 7%. The percentage relative contribution of each phase was significantly different (p<0.01) in each of the competition stages (time trials, flat stages, "high-mountain" stages and "medium-mountain" stages). Exercise intensity was particularly high during the time trials and high mountain stages. It may be concluded that during an endurance event such as the Tour de France, although the overall contribution of moderate (VT1 to VT2) or high intensity exercise (>VT2) is substantially lower than that of light, aerobic exercise (<VT1), a clear distinction must be made between the different type of stages (i.e. easy, flat parcours vs mountain stages or time trials) and the role of each cyclist in the team must be also considered.

Physiological parameters determined at OBLA vs. a fixed heart rate of 175 beats x min-1 in an incremental test performed by amateur and professional cyclists

A blood lactate concentration of 4 mmol x l-1 (OBLA) is frequently used as an indicator of the maximal steady state of lactate (MLSS) for workload planning in training programs. The aim of the present investigation was to compare several metabolic parameters determined at OBLA and at a fixed heart rate of 175 beats x min-1 (HR175) in amateur cyclists (AC) and professional cyclists (PC). Sixteen AC and 22 PC performed an exercise test on a cycle ergometer following a ramp protocol (25 W x min-1, 70-80 rpm) to exhaustion. Gaseous exchange was monitored throughout the test. VO2, %VO2 max, and power output (W) corresponding to OBLA and HR175 were determined and mean values compared using a Student's t-test. Findings indicated higher VO2 max and W in general in PC (p<0.01), and higher VO2 and W at OBLA and HR175 in PC (p<0.01). No significant difference was found between values determined at OBLA and HR175 in the AC group, while in the PC group, VO2, %VO2 max, and W were higher at OBLA. These observations suggest the possible use of a fixed, reference HR of 175 beats x min-1 to determine the exercise intensity corresponding to OBLA in amateur cyclists. This was not the case for the professional cyclists.

The importance of physical fitness in the performance of adequate cardiopulmonary resuscitation

The aim of the present investigation was to evaluate the influence of the physical fitness of a cardiopulmonary resuscitation (CPR) provider on the performance of and physiologic response to CPR. To this end, comparisons were made of sedentary and physically active subjects in terms of CPR performance and physiologic variables. Two study groups were established: group P (n=14), composed of sedentary, professional CPR rescuers (mean [+/-SD]; age, 34+/-6 years; VO2max, 32.5+/-5.5 mL/kg/min), and group Ex (n=14), composed of physically active, nonexperienced subjects (age, 34+/-6 years; VO2max, 44.5+/-8.5 mL/kg/min). Each subject was required to perform an 18-min CPR session, which involved manual external cardiac compressions (ECCs) on an electronic teaching mannequin following accepted standard CPR guidelines. Subjects' gas exchange parameters and heart rates (HRs) were monitored throughout the trial. Variables indicating the adequacy of the ECCs (ECC depth and the percentage of incorrect compressions and hand placements) also were determined. Overall CPR performance was similar in both groups. The indicators of ECC adequacy fell within accepted limits (ie, an ECC depth between 38 and 51 mm). However, fatigue prevented four subjects from group P from completing the trial. In contrast, the physiologic responses to CPR differed between groups. The indicators of the intensity of effort during the trial, such as HR or percentage of maximum oxygen uptake (VO2max) were higher in group P subjects than group Ex subjects, respectively (HRs at the end of the trial, 139+/-22 vs 115+/-17 beats/min, p < 0.01; percentage of VO2max after 12 min of CPR, 46.7+/-9.7% vs 37.2+/-10.4%, p < 0.05). These results suggest that a certain level of physical fitness may be beneficial to CPR providers to ensure the adequacy of chest compressions performed during relatively long periods of cardiac arrest.

Azelastine does not adversely affect aerobic performance

BACKGROUND

The effect of the treatment of allergic rhinitis with azelastine on physiological indicators of aerobic performance such as VO2 max and ventilatory threshold (VT) were evaluated. The clinical efficacy of azelastine was also established.

METHODS

EXPERIMENTAL DESIGN

fifteen physically active males with allergic rhinitis or rhinoconjunctivitis were selected as subjects (experimental group, EXP). Fifteen physically active, healthy subjects served as controls. Subjects performed a maximal incremental exercise test on a bicycle ergometer (ramp protocol) before and after a 5-day treatment period. During the 5 days, EXP group subjects were treated with azelastine (intranasal dose of 0.56 mg/day). The following variables were recorded before and after treatment: power output (W), HR (beats.min-1), VO2 (ml.kg-1.min-1), minute ventilation (VE, in 1.min-1), and oxygen pulse (VO2.HR-1, in ml.beat -1). Blood lactate concentrations (mmol.l-1) were also determined using capillary blood samples (25 microliters).

RESULTS

No significant difference was found between pre- and post-trial variables in control subjects. However, peak HR values were lower in EXP subjects after treatment with azelastine (190 +/- 6 beats.min-1 pre-treatment vs 186 +/- 56 beats.min-1 post-treatment; p < 0.05). In addition, VE values at the exercise intensity corresponding to VT were higher in EXP after treatment (54.7 +/- 12.8 l.min-1 pre-treatment vs 60.2 +/- 14.6 l.min-1 post-treatment, p < 0.05).

CONCLUSIONS

These findings suggest that the intranasal administration of azelastine used for the treatment of allergic symptoms of the upper respiratory tract in physically active subjects, does not seem to adversely affect maximal aerobic capacity or submaximal aerobic performance.

Saliva composition and exercise

Little attention has been directed toward identifying the changes which occur in salivary composition in response to exercise. To address this, our article first refers to the main aspects of salivary gland physiology. A knowledge of the neural control of salivary secretion is especially important for the understanding of the effects of exertion on salivary secretion. Both salivary output and composition depend on the activity of the autonomic nervous system and any modification of this activity can be observed indirectly by alternations in the salivary excretion. The effects of physical activity (with reference to factors such as exercise intensity and duration, or type of exercise protocol) on salivary composition are then considered. Exercise might indeed induce changes in several salivary components such as immunoglobulins, hormones, lactate, proteins and electrolytes. Saliva composition might therefore be used as an alternative noninvasive indicator of the response of the different body tissues and systems to physical exertion. In this respect, the response of salivary amylase and salivary electrolytes to incremental levels of exercise is of particular interest. Beyond a certain intensity of exercise, and coinciding with the accumulation of blood lactate (anaerobic threshold or AT), a 'saliva threshold' (Tsa) does indeed exist. Tsa is the point during exercise at which the levels of salivary alpha-amylase and electrolytes (especially Na+) also begin to rise above baseline levels. The occurrence of the 2 thresholds (AT and Tsa) might, in turn, be attributable to the same underlying mechanism, that of increased adrenal sympathetic activity at high exercise intensities.