Anaerobic threshold in runners and cyclists

Two different noninvasive procedures have been used to determine the anaerobic threshold (AT) in 15 long distance runners and in 6 cyclists. The AT values obtained by ventilatory methods (on treadmill for runners and on cycloergometer for cyclists) and the AT values obtained by a field test were significantly correlated.     

Nutritional practices of male and female endurance cyclists.

The nutritional requirements of the training and competition programmes of elite endurance cyclists are challenging. Notwithstanding the limitations of dietary survey techniques, studies of high-level male road cyclists provide important information about nutrient intake and food practices during training and major stage races. Typically, male cyclists undertaking intensive training programmes report a high energy intake (> or = 250 kJ/kg/day) and carbohydrate (CHO) intakes of 8 to 11 g/kg/day. Intakes of protein and micronutrients are likely to meet Recommended Dietary Intake levels, because of high energy intakes. Data on female cyclists are scarce. Stage racing poses an increased requirement for energy and CHO, with daily energy expenditure often exceeding 25 MJ. This must be achieved in the face of practical constraints on the time available for eating, and the suppression of appetite after exhausting exercise. However, studies show that male cyclists riding for professional teams appear to meet these challenges, with the assistance of their medical/scientific support crews. Current dietary practices during cycle tours appear to favour greater reliance on pre-stage intake and post-stage recovery meals to achieve nutritional goals. Recent reports suggest that current riding tactics interfere with previous practices of consuming substantial amounts of fluid and CHO while cycling. Further study is needed to confirm these practices, and to investigate whether these or other dietary strategies produce optimal cycling performance. Other issues that should receive attention include dietary practices of female cyclists, beliefs and practices regarding bodyweight control among cyclists, and the use of supplements and sports foods.     

Changes in plasma enzyme activities in professional racing cyclists.

OBJECTIVE: To reports changes in plasma levels in professional racing cyclists. METHODS: Plasma levels of the intracellular enzymes aspartate aminotransferase, alanine aminotransferase, gamma glutamyl transpeptidase, lactate dehydrogenase, and alkaline phosphatase were measured resting and after exercise in professional cyclists participating in two road races: Vuelta Ciclista a Valencia (800 km, beginning of the cyclist season), and the top rank race Vuelta a España (2700 km, at the end of cyclist season). RESULTS: A significant increase in plasma aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase was observed at the end of the race over the corresponding paired start values (P < 0.05). The increase in plasma lactate dehydrogenase after the race was only statistically significant (P < 0.05) in the Vuelta a España. The longer the duration of the cycle tour race, the greater were the increases in aspartate aminotransferase and alanine aminotransferase levels. The high levels returned to their start values during the overnight resting period. CONCLUSIONS: The presence of these enzymes in the blood is probably due to mechanically damaged muscle cells leaking their contents into the interstitial fluid.     

Ulnar and median nerve palsy in long-distance cyclists. A prospective study

BACKGROUND: Although case reports have identified the presence of distal ulnar nerve sensory and motor dysfunction in long-distance cyclists, the actual incidence of this condition, referred to as "cyclist's palsy," is unknown. PURPOSE: To determine the incidence of distal ulnar nerve compression in cyclists. STUDY DESIGN: Prospective study. METHODS: Twenty-five road or mountain bike riders responded to a questionnaire and were then physically examined and interviewed before and after a 600-km bicycle ride. RESULTS: Twenty-three of the 25 cyclists experienced either motor or sensory symptoms, or both. Motor symptoms alone occurred in 36% of the hands (11 cyclists) tested; no significant difference in the incidence of motor symptoms was found among cyclists of various experience levels or based on handlebar types (mountain bike versus road bike). Sensory symptoms alone occurred in 10% of hands (four cyclists) tested, with the majority of these being in the ulnar distribution. A significantly higher proportion of mountain bike riders had sensory deficits compared with road bike riders; however, there was no significant difference in the occurrence of sensory deficits based on level of experience. A total of 24% of the hands (eight cyclists) tested experienced a combination of motor and sensory symptoms. These motor and sensory symptoms were equally distributed between road bike riders and mountain bike riders and riders of various experience levels. CONCLUSIONS: Cyclist's palsy occurs at high rates in both experienced and inexperienced cylists. Steps may be taken to decrease the incidence of cyclist's palsy; these include wearing cycling gloves, ensuring proper bicycle fit, and frequently changing hand position.     

Hematological indices in elite cyclists

BACKGROUND: Blood testing is a major concern in sports. Sporting federations have introduced cut-off values for hematological variables to limit blood manipulations. To date, no reference margins have been established to adjust single- or multivariable blood tests to the exercise adapted blood cell system of athletes. We studied hemoglobin (Hb), hematocrit (Hct), blood cell variables and changes in vascular volumes in male and female national team cyclists to evaluate the influence of exercise on these variables and the results of blood tests, and to estimate normal ranges in athletes for blood tests. METHODS: 1628 blood samples of 169 male and 55 female athletes were considered. Samples were analyzed automatically, blood cell indices and vascular volumes were calculated. Overall averages and seasonal differences were estimated. RESULTS: Hb-average was: 15.4 +/- 0.8 g dL(-1) for male and 13.9 +/- 0.7 g dL(-1) for female cyclists, Hct: 45 +/- 2.9% and 40.7 +/- 2.7%. Blood variables and vascular volumes showed significant seasonal changes. 1-6% of all samples were found above the currently used limits for blood testing. This is in accordance with the data from the normal population. Nevertheless, EPO misuse or blood manipulations cannot totally be excluded. CONCLUSION: Athletes display seasonal adaptations in their blood profile which should be considered in testing regulations. The presented data might be used as reference values for indirect single- and multivariable blood tests.     

Bone density in competitive cyclists

To investigate current theories of the contributing factors to osteopenia/osteoporosis in competitive cyclists, we present a narrative review of published cross-sectional studies investigating plausible etiologies of decreased bone density in competitive cyclists. Aggregate from multiple published studies as cited. Bone mineral density in cyclists appears to be correlated positively to the cumulative amount of bone loading forces experienced over a lifetime. However, decreases in bone mineral density are noted over the short term if bone loading forces are removed, despite previous gains. There also appears to be a negative correlation between bone mineral density and dermal calcium losses during exercise. Data are mixed on whether calcium supplementation improves bone mineral density in this setting. No correlation was found between sex hormones and bone mineral density in the competitive cyclists studied. Knowledge of the underlying contributors to reduced bone mineral density in cyclists can aid in making preventative and therapeutic recommendations that potentially could decrease the morbidity and mortality related to osteoporosis.     

Physiological and performance characteristics of male professional road cyclists.

Male professional road cycling competitions last between 1 hour (e.g. the time trial in the World Championships) and 100 hours (e.g. the Tour de France). Although the final overall standings of a race are individual, it is undoubtedly a team sport. Professional road cyclists present with variable anthropometric values, but display impressive aerobic capacities [maximal power output 370 to 570 W, maximal oxygen uptake 4.4 to 6.4 L/min and power output at the onset of blood lactate accumulation (OBLA) 300 to 500 W]. Because of the variable anthropometric characteristics, 'specialists' have evolved within teams whose job is to perform in different terrain and racing conditions. In this respect, power outputs relative to mass exponents of 0.32 and 1 seem to be the best predictors of level ground and uphill cycling ability, respectively. However, time trial specialists have been shown to meet requirements to be top competitors in all terrain (level and uphill) and cycling conditions (individually and in a group). Based on competition heart rate measurements, time trials are raced under steady-state conditions, the shorter time trials being raced at average intensities close to OBLA (approximately 400 to 420 W), with the longer ones close to the individual lactate threshold (LT, approximately 370 to 390 W). Mass-start stages, on the other hand, are raced at low mean intensities (approximately 210 W for the flat stages, approximately 270 W for the high mountain stages), but are characterised by their intermittent nature, with cyclists spending on average 30 to 100 minutes at, and above LT, and 5 to 20 minutes at, and above OBLA.     

Radionuclide genital imaging.

Despite the emergence of newer cross-sectional imaging approaches, radionuclide techniques have maintained a significant role in genital imaging. While ultrasound is clearly superior for evaluation of scrotal anatomy, radionuclide scrotal imaging remains the most effective method for differentiating between testicular torsion and epididymitis. Labeled red blood cells have been used for varicocele detection in infertile men. Since radionuclide techniques can demonstrate the physiologic status of organs, they play a useful role in evaluating men with impotence (penile scan) and infertile women whose tubal patency is in question (radionuclide hysterosalpingogram).     

Adaptations to training in endurance cyclists: implications for performance.

Our present scientific knowledge of the effects of specific training interventions undertaken by professional cyclists on selected adaptive responses in skeletal muscle and their consequences for improving endurance performance is limited: sport scientists have found it difficult to persuade elite cyclists to experiment with their training regimens and access to muscle and blood samples from these athletes is sparse. Owing to the lack of scientific study we present a theoretical model of some of the major training-induced adaptations in skeletal muscle that are likely to determine performance capacity in elite cyclists. The model includes, but is not limited to, skeletal muscle morphology, acid-base status and fuel supply. A working premise is that the training-induced changes in skeletal muscle resulting from the high-volume, high-intensity training undertaken by elite cyclists is at least partially responsible for the observed improvements in performance. Using experimental data we provide evidence to support the model.     

Psychological, nutritional and physical status of olympic road cyclists.

Six members of the Irish Olympic Road Cycling Squad underwent a comprehensive medical, nutritional, psychological and biochemical assessment in January 1983. They were given specific medical and dietary recommendations and were reassessed in January 1984 after a period spanning the competitive racing season. The cyclists' diets at both sessions were comparable and generally conformed with recommended daily intakes. Supplementary ingestion was unnecessary to attain recommended daily intakes of vitamins. Serum levels of HDL-cholesterol increased and triglyceride decreased during the period of the study. The squad had characteristics indicating traits of self-sufficiency, toughness and practical mindedness. At the second assessment there was evidence of heightened ambition and competitiveness and an improvement in mood states with reduced ratings for confusion and tension.     

Immunological responses to overreaching in cyclists

INTRODUCTION: Acute bouts of prolonged strenuous exercise are often associated with immune suppression and an increased risk of infection. However, few studies have examined immunological responses to intensified training that results in overreaching or overtraining. We investigated the effects of intensified training on plasma cytokines, glutamine, glutamate, and other related immunological variables in endurance-trained cyclists. METHODS: Eight male subjects (age 27.0 +/- 3.0 yr, [OV0312]O(2max) 58.0 +/- 1.7 mL.kg-1.min-1, mass 73.7 +/- 2.1 kg) completed 6 wk of training: 2 wk each of normal training (N, 7 +/- 2 h.wk-1), intensified training (ITP, 14 +/- 5 h.wk-1) and recovery training (R, 3.5 +/- 2.5 h.wk-1). During the study period, subjects completed six graded cycle ergometer tests to exhaustion (MT), six simulated time trial tests (TT), and eight 2 x 10-min maximal effort bouts (IT). Subjects also completed questionnaires to assess mood state. Plasma concentrations of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6), salivary IgA, plasma glutamine, glutamate, ammonia, urea, creatine kinase activity, and routine hematological measures were determined once per week. RESULTS: ITP resulted in overreaching in all subjects identified by a significant decline in performance and disturbances of mood state. Significant increases during the ITP were observed in creatine kinase activity and glutamate, whereas the glutamine/glutamate ratio (Gln/Glu ratio), red blood cell numbers (RBC), hemoglobin concentration (Hb), and packed cell volume (PCV) declined after ITP. No significant changes were observed in TNF-alpha, IL-6, salivary IgA, glutamine, ammonia, urea and various routine hematological measures. CONCLUSION: Alterations in plasma cytokines do not appear to be related to the decline in performance and increased mood state characteristic of overreaching; however, the Gln/Glu ratio may be of use as a marker of overreaching and/or overtraining.     

Effects of heat stress on physiological responses and exercise performance in elite cyclists.

This study examined the effect of heat stress on physiological responses and exercise performance in elite road cyclists. Eleven members of the Australian National Road Cycling Squad completed two 30 min cycling time-trials in an environmental chamber set at either 32 degrees C, (HT) or 23 degrees C (NT) with a relative humidity of 60% in each circumstance. The trials were separated by two days, with six subjects performing HT first. Power output was 6.5% lower (P<0.05) during HT compared with NT. Mean skin temperature and sweat rate were higher (P<0.05) in HT compared with NT. In contrast, rectal temperature was remarkably similar throughout each trial. During the first 10 min of exercise in HT when power output was not different between trials, blood lactate was higher (P<0.05), and blood pH lower (P<0.05). In contrast, during the last 10 min of exercise when power output was reduced (P<0.05), blood lactate was lower (P<0.05), and pH higher (P<0.05), in HT. These data indicate that heat stress is associated with a reduced power output during self-paced exercise in highly trained men. This decrease in performance appears to be associated with factors associated with body temperature rather than metabolic capacity.     

Noninvasive estimation of the maximal lactate steady state in trained cyclists.

PURPOSE: The purposes of this study were to estimate noninvasively the maximal lactate steady state (MLSS) in trained cyclists on a windload simulator with a velocity based technique and to determine whether the HR at MLSS (HR(MLSS)) elicited a similar blood lactate concentration (BLC) during field testing. METHODS: To determine and verify MLSS, 10 male cyclists performed five to seven laboratory trials on separate days, including a VO2max test; a 5-km time trial (TT); and two or more 30-min trials at specific percentages of each subject's average 5-km TT speed (AVS5km). Mean+/-SD for the following variables were obtained at MLSS: velocity was 90.3+/-2.7% of the AVS5km, BLC was 5.4+/-1.6 mM, RPE was 15+/-2.1, VO2 was 80+/-6.3% of VO2max, and HR was 167+/-9.5 beats x min(-1), which was 88+/-3.8% of the mean maximum HR. Field tests included three laps of an 8-km road circuit at HR(MLSS) +/-3 beats x min(-1) and one lap at maximum sustainable velocity (a road TT). RESULTS: There were no significant differences in BLC, HR, and RPE between the three steady-state road laps and the lab MLSS trial. There was also good agreement between the road and lab MLSS velocity/TT velocity ratios. Conclusions: Our data suggest that 5-km TT cycling velocity, as measured on a windload simulator, may be used to estimate MLSS and the HR at MLSS for training purposes.     

Hydrocolloid dressing versus tulle gauze in the treatment of abrasions in cyclists.

Abrasions in cyclists were either treated with an occlusive hydrocolloid dressing or with tulle gauze. The main object of the study was to investigate practical questions, e.g: Could the cyclists go on racing without their injuries impeding their progress? Medical aspects evaluated in the study were: the healing time and the infection rate of the wounds. Twenty-three racing cyclists with 38 abrasions were treated with a hydrocolloid dressing and 41 abrasions in 24 cyclists with tulle gauze. The results of the study show that the occlusive dressing produces a shorter healing time (5.6 days) than the tulle gauze (8.9 days), with smaller risks of infection (0% and 10%, respectively) and a longer wearing period per dressing. The hydrocolloid dressing also gives more pain relief than the tulle gauze (91% no pain during racing with the hydrocolloid dressing, 30% with the tulle gauze) and a higher overall comfort (very comfortable to comfortable versus uncomfortable to moderately uncomfortable, respectively).     

Synchronous genital tract neoplasms.

Synchronous genital tract neoplasms constitute a more common clinical problem than would be generally expected. This case focuses on mixed mullerian tumours and postulates a mechanism for an increased incidence found associated with synchronous genital tract neoplasms.     

ACTN3 genotype in professional endurance cyclists

The Z-disk protein alpha-actinin-3 is only expressed in type II muscle fibres, which are responsible for generating forceful contractions at high velocity. Despite the evolutionary conservation of alpha-actinin-3, approximately one in every five Caucasians of European ancestry is totally deficient in this protein, due to homozygosity for a R577X polymorphism in the ACTN3 gene. This, together with the results of recent research on elite athletes, suggests that the "null" XX polymorphism might confer some advantage to endurance performance events. To test this hypothesis, we studied the frequency distribution of R577X genotypes in a group of 50 top-level male professional cyclists (26.9 +/- 0.4 yrs [mean +/- SEM]; VO2max: 73.5 +/- 0.8 ml x kg (-1) x min (-1)). Their results were compared with those of a group of 52 Olympic-class male endurance runners (26.8 +/- 0.6 yrs; VO2max: 73.3 +/- 0.8 ml x kg (-1) x min (-1)) and 123 healthy, sedentary male controls. All subjects were Caucasian, and of European ancestry. No significant differences (p > 0.05) were found between groups: RR: 28.5 %; RX: 53.6 % and XX: 17.9 % in controls; RR: 28.0 %; RX: 46.0 % and XX: 26.0 % in cyclists; and RR: 25.0 %; RX: 57.7 %; XX: 17.3 % in runners). No differences were found in indices of endurance performance (VO2peak or ventilatory thresholds) between athlete carriers of each R577X genotype. In summary, although the alpha-actinin-3 deficient XX genotype may be detrimental for sprint performance in humans, the R577X polymorphism of the ACTN3 gene does not appear to confer an advantage on the ability of male athletes to sustain extreme endurance performance.     

Body position affects performance in untrained cyclists

OBJECTIVE: To compare cardiovascular and ventilatory variables in upright versus aero cycle ergometry at submaximal and maximal exercise intensities in untrained cyclists. METHOD: Ten physically active men (mean (SD) age 19.1 (1.10) years) who were unfamiliar with aerobars underwent maximal exercise testing and steady state cycling at 50, 100, and 150 W. RESULTS: Participants had significantly greater maxima for oxygen uptake (VO2), ventilation, heart rate, and workload maximum in the upright position. During steady state cycling at the three workloads, VO2 (ml/kg/min) and gross mechanical efficiency were significantly greater in the upright position. CONCLUSIONS: In untrained subjects performing with maximal effort, the upright position permits greater VO2, ventilation, heart rate, and workload maxima. Further, in the steady state, exercise cycling may be less costly in the upright position. For this reason, untrained cyclists need to weigh body position effects against the well known aerodynamic advantages of the aero position.     

Left ventricular remodeling in elite and sub-elite road cyclists

Marked adaptation of left ventricular (LV) structure in endurance athletes is well established. However, previous investigations of functional and mechanical adaptation have been contradictory. A lack of clarity in subjects’ athletic performance level may have contributed to these disparate findings. This study aimed to describe structural, functional, and mechanical characteristics of the cyclists’ LV, based on clearly defined performance levels. Male elite cyclists (EC) (n = 69), sub-elite cyclists (SEC) (n = 30), and non-athletes (NA) (n = 46) were comparatively studied using conventional and speckle tracking 2D echocardiography. Dilated eccentric hypertrophy was common in EC (34.7%), but not SEC (3.3%). Chamber concentricity was higher in EC compared to SEC (7.11 ± 1.08 vs 5.85 ± 0.98 g/(mL)^2/3, P < .001). Ejection fraction (EF) was lower in EC compared to NA (57 ± 5% vs 59 ± 4%, P < .05), and reduced EF was observed in a greater proportion of EC (11.6%) compared to SEC (6.7%). Global circumferential strain (GCε) was greater in EC (−18.4 ± 2.4%) and SEC (−19.8 ± 2.7%) compared to NA (−17.2 ± 2.6%) (P < .05 and P < .001). Early diastolic filling was lower in EC compared with SEC (0.72 ± 0.14 vs 0.88 ± 0.12 cm/s, P < .001), as were septal E’ (12 ± 2 vs 15 ± 2 cm/s, P < .001) and lateral E’ (18 ± 4 vs 20 ± 4 cm/s, P < .05). The magnitude of LV structural adaptation was far greater in EC compared with SEC. Increased GCε may represent a compensatory mechanism to maintain stroke volume in the presence of increased chamber volume. Decreased E and E’ velocities may be indicative of a considerable functional reserve in EC.     

Haemoglobin mass in cyclists during stage racing

Haemoglobin mass is a main determinant of maximal oxygen uptake. Blood doping aims at increasing this variable. Limits for haematocrit and haemoglobin concentration are used as indicators of blood doping. However, these variables are measures of concentration, do not represent total haemoglobin mass and are altered by vascular volumes shifts. Direct estimation of haemoglobin mass could improve blood tests. It is unknown if physical exercise alters haemoglobin mass. The purpose of this study was to investigate the reaction of haemoglobin mass and other vascular compartments to heavy exercise in athletes. Haemoglobin mass and vascular compartments were evaluated using the optimised CO rebreathing method in 7 elite cyclists during a stage race. Simultaneously, haemoglobin concentration and haematocrit were analysed. Haemoglobin mass (pre-race 958 +/- 123 g, end race 948 +/- 106 g) and red cell volume did not change significantly over the study period, while plasma volume and blood volume tended to increase. Haematocrit (pre-race 44.1 +/- 2.5 %, end race 40.9 +/- 1.59 %) and haemoglobin concentration (pre race 15.8 +/- 0.9 g/dl, end race 14.7 +/- 0.7 g/dl) decreased. During the study, a plasma volume expansion as adaptation to prolonged exercise occurred. Haemoglobin concentration and haematocrit decreased accordingly, whereas haemoglobin mass remained stable. Haemoglobin mass might therefore be a suitable screening tool for blood manipulations.