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AB Purpose: A bioenergetical analysis of different exercise modes near maximal oxygen consumption (V[spacing dot above]O2max) intensity is scarce, hampering the prescription of training to enhance performance. We assessed the time sustained in swimming, rowing, running, and cycling at an intensity eliciting V[spacing dot above]O2max and determined the specific oxygen uptake (V[spacing dot above]O2) kinetics and total energy expenditure (Etot-tlim). Methods: Four subgroups of 10 swimmers, 10 rowers, 10 runners, and 10 cyclists performed (i) an incremental protocol to assess the velocity (vV[spacing dot above]O2max) or power (wV[spacing dot above]O2max) associated with V[spacing dot above]O2max and (ii) a square wave transition exercise from rest to vV[spacing dot above]O2max/wV[spacing dot above]O2max to assess the time to voluntary exhaustion (Tlim-100%V[spacing dot above]O2max). The V[spacing dot above]O2 was measured using a telemetric portable gas analyzer (K4b2, Cosmed, Rome, Italy) and V[spacing dot above]O2 kinetics analyzed using a double exponential curve fit. Etot-tlim was computed as the sum of its three components: aerobic (Aer), anaerobic lactic (Analac), and anaerobic alactic (Anaalac) contributions. Results: No differences were evident in Tlim-100% V[spacing dot above]O2max between exercise modes (mean +/- SD: swimming, 187 +/- 25; rowing, 199 +/- 52; running, 245 +/- 46; and cycling, 227 +/- 48 s). In contrast, the V[spacing dot above]O2 kinetics profile exhibited a slower response in swimming (21 +/- 3 s) compared with the other three modes of exercise (rowing, 12 +/- 3; running, 10 +/- 3; and cycling, 16 +/- 4 s) (P < 0.001). Etot-tlim was similar between exercise modes even if the Analac contribution was smaller in swimming compared with the other sports (P < 0.001). Conclusion: Although there were different V[spacing dot above]O2 kinetics and ventilatory patterns, the Tlim-100%V[spacing dot above]O2max was similar between exercise modes most likely related to the common central and peripheral level of fitness in our athletes.

AB Purpose: The objective of this study is to investigate the relation between sport training and the risk of common illnesses: upper respiratory tract and pulmonary infections (URTPI), muscular affections (MA), and all-type pathologies in highly trained swimmers. Methods: Twenty-eight French professional swimmers were monitored weekly for 4 yr. Training variables included 1) in-water and dryland intensity levels: low-load, high-load, resistance, maximal strength, and general conditioning training (expressed as the percentage of the maximal load performed by each subject, at each intensity level over the study period); and 2) training periods: moderate, intensive, taper, competition, and postcompetition. Illnesses were diagnosed by a sports physician using a standardized questionnaire. Mixed-effects logistic regression analyses were used to model odds ratios for the association between common illnesses and training variables, adjusted for sport season, semiseason (summer or winter), age, competition level, sex, and history of recent events, whereas controlling for heterogeneity among swimmers. Results: The risk of common illnesses was significantly higher in winter months, for national swimmers (for URTPI), and in cases of history of recent event (notably for MA). The odds of URTPI increased 1.08 (95% CI, 1.01-1.16) and 1.10 (95% CI, 1.01-1.19) times for every 10% increase in resistance and high-load trainings, respectively. The odds of MA increased by 1.49 (95% CI, 1.14-1.96) and 1.63 (95% CI, 1.20-2.21) for each 10% increase in high load and general conditioning training, respectively. The odds of illnesses were 50%-70% significantly higher during intensive training periods. Conclusion: Particular attention must be paid to illness prevention strategies during periods of intensive training, particularly in the winter months or in case of the recent medical episode.

PURPOSE: To investigate the impact of CHO re-introduction in athletes previously adapted to a LCHF diet on subsequent inflammatory and hepcidin responses to exercise. METHODS: In the three weeks prior to the exercise trials, twenty-three elite race walkers adhered to either a CHO-rich (n=14) or LCHF diet (n=9). A 19-25 km race walking protocol was performed while the race walkers were still adhering to their allocated dietary intervention (Adapt). A second exercise test was performed three days later, where the LCHF consumed CHO 2 h prior to, and during the exercise protocol (in line with sports nutrition guidelines) for the first time in 3.5 weeks (CHO Restoration). Venous blood samples were collected pre-, post- and 3 h post-exercise and analysed for serum ferritin, interleukin-6 (IL-6) and hepcidin-25. RESULTS: Serum ferritin concentration was similar between trials (p=0.48) and dietary groups (p=0.93). The post-exercise IL-6 increase was greater in LCHF (p

There is need for valid and powerful research designs to assess performance effects of interventions in squads of elite athletes.The objective of this study is to develop a design for investigating effects on competition performance using performance of athletes in other squads as a control.We used competition swim times downloaded from USAswimming.org for a season ending in the US Open and assumed an intervention had been applied to athletes in one of the larger squads (Ford) at one competition (Santa Clara). Data were included only for swimmers who achieved900 Hy-Tek points at the USA Swimming Nationals. Each swimmer's points were used to select their best event. Times for the resulting 368 best-event swims in seven competitions by 148 swimmers in 19 squads were analyzed to determine the uncertainty (90% confidence interval) of the effect of the hypothetical intervention. Further analyses were performed with other selection criteria. Uncertainties were compared with those in other recent studies of competitive senior swimmers.Uncertainty in the effect of an intervention applied to Ford for Santa Clara would have been ±0.8%. Applying other data-selection criteria resulted in generally more uncertainty. Uncertainties in recent studies of competitive swimmers using conventional designs ranged between ±0.7% and ±2.2%.For the sport of swimming, the effects with this new design are at least as precise as those of conventional research designs using performance tests, and the outcomes are likely to have higher validity. The new design should be useful for assessing the effect of an intervention representing a substantial change from a baseline of usual practice in any sport where athletes compete often against athletes of other squads.

Elite athletes often undertake multiple altitude exposures within and between training years in an attempt to improve sea level performance. Purpose: To quantify the reproducibility of responses to live high/train low (LHTL) altitude exposure in the same group of athletes. Methods: Sixteen highly trained runners with maximal aerobic power (V˙O2max) of 73.1 ± 4.6 and 64.4 ± 3.2 mL·kg−1·min−1 (mean ± SD) for males and females, respectively, completed 2 × 3-wk blocks of simulated LHTL (14 h·d−1, 3000 m) or resided near sea level (600 m) in a controlled study design. Changes in the 4.5-km time trial performance and physiological measures including V˙O2max, running economy and hemoglobin mass (Hbmass) were assessed. Results: Time trial performance showed small and variable changes after each 3-wk altitude block in both the LHTL (mean [±90% confidence limits]: −1.4% [±1.1%] and 0.7% [±1.3%]) and the control (0.5% [±1.5%] and −0.7% [±0.8%]) groups. The LHTL group demonstrated reproducible improvements in V˙O2max (2.1% [±2.1%] and 2.1% [±3.9%]) and Hbmass (2.8% [±2.1%] and 2.7% [±1.8%]) after each 3-wk block. Compared with those in the control group, the runners in the LHTL group were substantially faster after the first 3-wk block (LHTL − control = −1.9% [±1.8%]) and had substantially higher Hbmass after the second 3-wk block (4.2% [±2.1%]). There was no substantial difference in the change in mean V˙O2max between the groups after the first (1.2% [±3.3%]) or second 3-wk block (1.4% [±4.6%]). Conclusions: Three-week LHTL altitude exposure can induce reproducible mean improvements in V˙O2max and Hbmass in highly trained runners, but changes in time trial performance seem to be more variable. Competitive performance is dependent not only on improvements in physiological capacities that underpin performance but also on a complex interaction of many factors including fitness, fatigue, and motivation.

Purpose: To characterize differences in cytokine responses to exercise of different intensities and durations between healthy and illness-prone runners. Methods: Trained distance runners were classified as healthy (no more than two episodes of upper-respiratory symptoms per year; N = 10) or illness-prone (four or more episodes per year; N = 8) and completed three treadmill tests: SHORT (30 min, 65% V[spacing dot above]O2max), LONG (60 min, 65% V[spacing dot above]O2max), and INTENSE (6 x 3 min, 90% V[spacing dot above]O2max). Blood samples were collected pre-, post-, 1 h, 10 h, and 24 h after exercise, and interleukin (IL)-2, IL-4, IL-6, IL-8, IL-10, IL-12, and IL-1ra concentrations were determined. Repeated-measures ANOVA was used to assess changes in cytokine responses to exercise. Magnitudes of changes and differences between groups were characterized using Cohen's effect size (ES) criteria. Results: Resting IL-8, IL-10, and IL-1ra concentrations were 19-38% lower (ES:0.38-0.96; small to moderate differences) in illness-prone runners. Similarly, postexercise IL-10 concentrations were 13-20% lower (ES: 0.20-0.37; small differences), and IL-1ra concentrations were 10-20% lower (ES: 0.22-0.38; small differences) in illness-prone subjects. In contrast, IL-6 elevations were 84-185% higher (ES: 0.29-0.59, small differences) in illness-prone subjects. Postexercise responses of IL-2, IL-4, and IL-12 were small and not substantially different between the groups. Conclusions: Cytokine responses to controlled treadmill running differ between healthy and illness-prone athletes. Illness-prone distance runners showed evidence suggestive of impaired inflammatory regulation in the hours after exercise that may account for the greater frequency of upper-respiratory symptoms experienced.

Upper respiratory illness (URI) is the most common medical condition affecting elite athletes. The aims of this study were to identify and evaluate the incidence, pathogenic etiology, and symptomatology of acute URI during a 5-month training and competition period.Thirty-two elite and 31 recreationally competitive triathletes and cyclists, and 20 sedentary controls (age range 18.0-34.1 yr) participated in a prospective surveillance study. Nasopharyngeal and throat swabs were collected from subjects presenting with two or more defined upper respiratory symptoms. Swabs were analyzed using microscopy, culture, and PCR testing for typical and atypical respiratory pathogens. The Wisconsin Upper Respiratory Symptom Survey (WURSS-44) was used to assess symptomatology and functional impairment.Thirty-seven URI episodes were reported in 28 subjects. Incidence rate ratios for illness were higher in both the control subjects (1.93, 95% CI: 0.72-5.18) and elite athletes (4.50, 1.91-10.59) than in the recreationally competitive athletes. Infectious agents were identified in only 11 (two control, three recreationally competitive, and six elite) out of 37 illness episodes. Rhinovirus was the most common respiratory pathogen isolated. Symptom and functional impairment severity scores were higher in subjects with an infectious pathogen episode, particularly on illness days 3-4.The results confirm a higher rate of URI among elite athletes than recreationally competitive athletes during this training and competition season. However, because pathogens were isolated in fewer than 30% of URI cases, further study is required to uncover the causes of unidentified but symptomatic URI in athletes. Despite the common perception that all URI are infections, physicians should consider both infectious and noninfectious causes when athletes present with symptoms.

FRANCIS, J. L., M. GLEESON, D. B. PYNE, R. CALLISTER, and R. L. CLANCY. Variation of Salivary Immunoglobulins in Exercising and Sedentary Populations. Med. Sci. Sports Exerc., Vol. 37, No. 4, pp. 571–578, 2005. Purpose: This study examined the nature of the variability in salivary immunoglobulin and albumin concentrations within an individual, between individuals, and between populations with differing levels of habitual physical activity. Methods: Fourteen elite swimmers, and 21 active and 18 sedentary individuals provided 12 saliva samples over a 30-d period. Group classifications were based on interviews, anthropometric measurements, and physical activity records. Symptoms of illness and physical activity data were recorded daily. Salivary IgA, IgG, and IgM were measured by ELISA, and albumin concentrations were measured by nephelometry. Variability was assessed using ANOVA procedures. Results: Elite swimmers, compared with active and sedentary individuals, had higher concentrations of salivary IgA (geometric mean 65 vs 32 and 40 mg·L 1 , P 0.002) and greater variability in salivary IgA concentrations as individuals (P 0.007) and as a group (P 0.03). Salivary IgG variability in swimmers was also twofold greater than the other two groups (P 0.008). Salivary IgM and albumin variability were not significantly different between groups, but individual variability differed for swimmers and active individuals. The intraclass correlations for salivary IgA and IgG (but not for IgM or albumin) were 50% lower for swimmers than the other two groups (ICC for IgA: 20% swimmers vs 54% active and 46% sedentary individuals; ICC for IgG: 36 vs 59 and 57%). Conclusion: The variability and fluctuation of salivary immunoglobulin concentrations were consistently greater in the elite swimmers, but multiple samples from individual swimmers were less correlated compared with participants with lower physical activity levels. These findings have implications for monitoring mucosal immune status within individuals and when comparing salivary immunoglobulin concentrations between groups with differing levels of physical fitness and activity. Key Words: MUCOSAL IMMUNITY, SECRETORY IGA, EXERCISE, SWIMMERS, VARIABILITY

To establish the typical error (TE) associated with equipment, testing, and biological variation of a running economy (RE) test in 11 elite male distance runners (VO2max 70.3 +/- 7.3 mL x min(-1) x kg(-1)), and measure the between-athlete variation of 70 highly trained runners (VO2max 69.7 +/- 6.0 mL x min(-1) x kg(-1)) to determine the magnitude of the smallest worthwhile change (SWC) required for RE.Runners performed three 4-min bouts of submaximal treadmill running at speeds of 14, 16, and 18 km x h(-1) (0% grade), on two separate occasions within a 7-d period to determine reliability and once over a 3-yr period to measure the SWC. During all RE tests O2 consumption (VO2), ventilation (VE), respiratory exchange ratio (RER), heart rate (HR), stride rate (SR), and concentration of blood lactate (Lac) were determined.The TE for the pooled data of three running speeds (14, 16, and 18 km x h(-1)) was 2.4% for VO2, 7.3% for VE, 27% for Lac, and ranged between 1 and 4% for RER, HR, and SR.The results demonstrate that although the magnitude of the TE for a submaximal treadmill running protocol of three 4-min work efforts is small (2.4-7.3%) for measures associated with cardiorespiratory parameters, it is three- to fourfold higher for Lac. Given the small TE associated with RE, and a SWC of similar magnitude for this cohort of distance runners, the RE test is useful in detecting changes attributable to training interventions. Changes in RE greater than approximately 2.4% in this cohort of elite distance runners are likely to be "real" and "worthwhile," and not simply related to testing error and typical variation.

COX, A. J., M. GLEESON, D. B. PYNE, P. U. SAUNDERS, R. L. CLANCY, and P. A. FRICKER. Valtrex TM Therapy for Epstein-Barr Virus Reactivation and Upper Respiratory Symptoms in Elite Runners. Med. Sci. Sports Exerc., Vol. 36, No. 7, pp. 1104 –1110, 2004. Purpose: The aim of the study was to examine the effectiveness of prophylactic administration of the antiviral agent Valtrex TM for control of Epstein-Barr virus (EBV) reactivation and upper respiratory symptoms in elite distance runners. Methods: Twenty elite male distance runners were randomized into a 4-month double-blind, placebo-controlled cross-over trial. Saliva samples were collected weekly and mucosal immune status assessed by measurement of secretory IgA (SIgA) using an enzyme-linked immunosorbent assay (ELISA). EBV reactivation was monitored at the same time by detection of EBV in saliva using a quantitative real-time polymerase chain reaction. The initial EBV status of the runners was determined by detecting EBV antibodies in serum using an ELISA. Upper respiratory symptoms were recorded using self-reporting illness logs. Results: There was no evidence of any marked change in maximal oxygen uptake (P 0.86), training volume (P 0.30), or mucosal immunity (P 0.21) over the study period. Valtrex TM treatment resulted in an 82% reduction in the detectable EBV load in saliva for EBV seropositive runners compared with the placebo treatment (P 0.04). The incidence of upper respiratory symptoms was not reduced by Valtrex TM treatment. Conclusions: The prophylactic administration of Valtrex TM reduced EBV reactivation but was not an effective intervention strategy for limiting upper

The effects of exercise on the immune system has been shown to be dependent on the level of fitness of the subjects, the degree of intensity, and the duration of the exercise. A reduction in salivary IgA levels occurs after individual sessions of exercise. Purpose: The purpose of this study was to assess the relationship between changes in salivary IgA and training volume, psychological stress, and infection rates in a cohort of 26 elite swimmers over a 7-month training period and to compare the changes with a group of 12 moderately exercising controls. Methods: Salivary IgA concentrations were measured by an electroimmunodiffusion. Exercise gradings were assessed by a standardized aerobic-anaerobic rating system. Psychological stress/anxiety was evaluated by the Spielberger State-Trait Anxiety Inventory. Infections were physician-verified. Results: Salivary IgA levels showed an inverse correlation with the number of infections in both elite swimmers and moderately exercising control subjects. The pretraining salivary IgA levels in swimmers were 4.1% lower for each additional month of training and 5.8% lower for each additional infection. The posttraining salivary IgA levels in swimmers were not significantly correlated with infection rates but were 8.5% lower for each additional I km swum in a training session and 7.0% lower for each additional month of training. The number of infections observed in the elite swimmers was predicted from regression models by the preseason (P = 0.05) and the mean pretraining salivary IgA levels (P = 0.006). The trends in pretraining salivary IgA levels over the 7-month season, calculated as individual slopes of pretraining IgA levels over time, were also predictive of the number of infections (P = 0.03) in the swimmers. Conclusions: These results indicate that measurement of salivary IgA levels over a training season may be predictive for athletes at risk of infection.

PURPOSETo evaluate the utility of an incremental swimming test for monitoring seasonal changes in performance of elite swimmers. METHODSOlympic representative 100- to 400-m swimmers (10 males, 9 females) performed a 7 × 200-m incremental swimming step test several times throughout each 6-month season during 1998–2002. Each season concluded with a national or international competition. Log transformation and repeated measures mixed linear modeling were used to derive estimates of percent change in the mean and within-swimmer coefficient of variation (CV) for swim times between seasons and for the following test measures between phases and seasons: speed, stroke rate, stroke count and heart rate at lactate threshold; speed for the maximal (last) 200-m step; and maximal lactate. Change in competition time was modeled as a linear function of change in each of the step-test measures between season. We also determined the 3-day retest typical error for the test measures in a reliability study of 12 of the swimmers.RESULTS Test measures directly related to swimming performance showed cyclical improvement (mean ~2%) from early through to taper phases within each season, and within-swimmer variation was of similar magnitude. These changes can be monitored confidently in individuals, because the typical error of the test measures was substantially smaller (e.g. lactate-threshold speed, 0.7%; maximal speed 0.6%). Competition times improved slightly each season (0.2%) against a within-swimmer variation of 1.0% between competitions, but typical (1 × CV) changes in test measures between seasons predicted worthwhile changes in competition time (> 0.4%) only for tests in the taper and only for speed (0.8%) and stroke rate (0.6%) at lactate threshold and for maximum lactate (0.5%).CONCLUSIONThe step test can track changes in a swimmer's performance during a season, but it appears to be useful for predicting competitive performance only during the taper.

The effects of an intensive 12-wk training program by 12 national-level swimmers on neutrophil oxidative activity were studied. Eleven sedentary (untrained) subjects (6 males and 5 females) served as environmental controls. Blood samples (10 ml) were taken at rest from an antecubital vein and neutrophils isolated by standard separation techniques. The oxidative burst activity of isolated neutrophils was assessed with an in vitro flow cytometric assay that used the fluorescent probe dihydrorhodamine 123. Two-way ANOVA (repeated measures) showed that oxidative activity was lower (P < 0.05) in the elite swimmers compared with the sedentary control group across the 12-wk period. Analysis of cells from swimmers in training was made: repeated measures ANOVA provided evidence of a significant decline (P < 0.05) in the number of cells responding positively ito in vitro challenge. Despite this decline, there was no significant difference in self-reported upper respiratory tract infection rate between the swimmers and sedentary individuals. These data show that: (i) elite swimmers undertaking intensive training have a significantly lower neutrophil oxidative activity at rest than do age- and sex-matched sedentary individuals; (ii) aspects of oxidative activity in swimmers are further suppressed during periods of strenuous training, and (iii) the extent of the suppression does not appear to be of clinical significance.