Triathlon World Championships Research Articles

Neuromuscular changes after a Long Distance Triathlon World Championship

ABSTRACT This study aimed to determine the neuromuscular changes in muscle contractile properties and countermovement jump (CMJ) performance after a long distance (LD) triathlon, inquiring to what extent it is influenced by gender and the evaluated muscle, and to explore for response differences. Four elite (2 females and 2 males) and 18 well-trained triathletes (3 females and 15 males) who competed in the 2019 LD Triathlon World Championship undergone, prior and post-race, a CMJ and a muscle contractile properties assessment in vastus lateralis (VL) and biceps femoris (BF) using tensiomyography. A mixed ANOVA was carried out to detect triathletes’ neuromuscular changes after the competition. A large decrease in jump height and flight time was found in CMJ (p = 0.001, ηp 2 = 0.767) with gender differences (ηp 2 = 0.308). contraction (Tc), delay (Td) and sustain times (Ts) also showed a large decrease (p = 0.001, ηp 2 = 0.174–0.413). However, maximum radial muscle belly displacement was not altered by the competition, but did greatly increase radial displacement velocity (p = 0.031; ηp 2 = 0.212). No gender differences were found in contractile properties. Correlation analysis between race performance and the jumping and tensiomyography parameters only showed a moderate negative correlation with Tc of the BF in pre- and post-competition (r = −0.44; −0.43; p = 0.05). In conclusion, triathletes after a LD World Championship suffer a sharp drop in jump performance and variations in VL’s and BF’s contractile properties, showing decreases in Tc, Td and Ts without gender differences. The regular use of these parameters can allow the monitoring of triathlete's neuromuscular fatigue and aid in the distribution of more efficient loads in their training cycles. Highlights Trainers and researchers in neuromuscular fatigue can have reference data of elite and well-trained triathletes after performing LD race. The magnitude of change in the CMJ and the contractile properties of BF and VL achieved in competition by these elite reference triathletes can guide to modulate triathletes training. The regular use of the parameters using these references can allow an exhaustive neuromuscular fatigue monitoring during the sessions or training cycles throughout the season.

Effect of age on the sex difference in Ironman triathlon performance

The aim of this study was to investigate the effect of age on the sex differences in (3.8 km) swim, (180 km) cycle, (42 km) run, and overall performance time at the 2018 Ironman triathlon World Championship. Sex differences in performance times were analysed for the top 10 male and female amateur triathletes of each 5 years age group between 18–24 years and 70–74 years. Independent of age, the averaged sex difference in swimming, cycling, running, and overall performance time was 14.0 ± 3.3%, 15.6 ± 3.1%, 15.3 ± 6.8% and 15.1 ± 3.6%, respectively. There was no significant change with age in the sex difference in performance for swimming. For both cycling and running, the sex difference in performance of the age groups whose athletes were older than 60 years were significantly greater than those of younger age groups. Such results suggest that, in Ironman triathletes, the increase in the sex difference in performance with advancing age is discipline dependent. Further examination of the (physiological and training load related) factors that are associated with the age-related decline in Ironman triathlon performance is required to understand why the sex difference in cycling and running performance increases with age.

Age and Gender Differences in Performance at Cross Triathlon World Championships

Abstract Introduction. Cross triathlon is a sport consisting of three segments: swimming, off-road cycling, and running. Our study analyses the differences in performance between genders and changes in performance in selected age categories at the ITU Cross World Championships held between 2011 and 2016. Material and methods. During this period, a total of 1,933 triathletes were analysed (1,472 men and 461 women). Two-way analyses of variance (ANOVA) were used to examine the impact of sex differences and age-related changes on performance (time, percentage of time, and performance ratio) in swimming, cycling, running, and total race. Results. The age groups with the highest level of participation were persons aged 40-44 and 45-49 years among men and women, respectively. With regards to performance in the different age groups, in men and women, its high level was maintained between 25 and 49 years, and it decreased significantly from the age of 50-54. In men, the best results in cycling and total race time were obtained in the 30-34 age group and in swimming and running in the 40-44 group. Women obtained the best results in running in the 25-29 age group, in cycling in the 30-34 group, and in swimming and total race time in the 35-39 group. Conclusions. The results of the study have confirmed that there is a demand for sports in 40+ age groups. As for performance in the different age groups, it was on a high level between 25 and 49 years and decreased significantly from the age of 50-54 onwards. According to these results, the sports training of these triathletes should be oriented so that they obtain their best results between 30 and 35 years of age.

The influence of swim, cycle and run performance on overall race outcome at the off-road triathlon world championships

The purpose of this study was to determine whether swim, cycle or run performance best predicts overall position during the off-road triathlon world championships. Data were collected for the top 10 finishers at each male and female world championships between 2007 and 2016. Multiple linear regression was used to predict the influence of each discipline on finishing in the top 10 overall over the 10 years, whilst one-way between subjects analysis of variance (ANOVA’s) were conducted to determine any differences in mean overall finishing time, swim, cycle and run times of the top 10 finishers between years. Cycling best predicted overall position (R2 = 0.31), followed by the run and swim (R2 = 0.17 and 0.16, respectively) for males. For females the run best predicted overall performance (R2 = 0.46), then the cycle and swim (R2 = 0.26 and 0.15, respectively). ANOVA analyses found significant differences for males in swim time (F9,99 = 4.32; p < 0.001; ηp2 = 0.30), cycle time (F9,99 = 48.33; p < 0.001; ηp2 = 0.83), run time (F9,99 = 22.89; p < 0.001; ηp2 = 0.70) and overall time (F9,99 = 59.12; p < 0.001; ηp2 = 0.86). Similarly, significant differences were also found for females in swim time (F9,99 = 3.60; p = 0.001; ηp2 = 0.26), cycle time (F9,99 = 37.14; p < 0.001; ηp2 = 0.79), run time (F9,99 = 13.77; p < 0.001; ηp2 = 0.58) and overall time (F9,99 = 28.17; p < 0.001; ηp2 = 0.74) by year. Results indicate there are differences in the influence of each discipline for males and females over the 10 years and between years. Environmental conditions and competitive background may be influential in these findings.

Sex difference in race performance and age of peak performance in the Ironman Triathlon World Championship from 1983 to 2012

BackgroundThe fastest Ironman race times in ‘Ironman Hawaii’ were achieved in very recent years. This study investigated the change in sex difference in both race performance and the age of peak performance across years in the top ten athletes for split disciplines and overall race time in the ‘Ironman Hawaii’ between 1983 and 2012.MethodsChanges in split times, overall race times, and age of athletes across years for the top ten overall and the fastest swimmers, cyclists, and runners were investigated using regression analyses and analyses of variance.ResultsBetween 1983 and 2012, the overall top ten men and women finishers improved their swimming (only men), cycling, running, and overall race times. The sex difference in overall race time decreased significantly (p = 0.01) from 15.2% to 11.3% across time. For the split disciplines, the sex difference remained unchanged (p > 0.05) for swimming (12.5 ± 3.7%) and cycling (12.5 ± 2.7%) but decreased for running from 13.5 ± 8.1% to 7.3 ± 2.9% (p = 0.03). The time performance of the top ten swimmers remained stable (p > 0.05), while those of the top ten cyclists and top ten runners improved (p < 0.01). The sex difference in performance remained unchanged (p > 0.05) in swimming (8.0 ± 2.4%), cycling (12.7 ± 1.8%), and running (15.2 ± 3.0%). Between 1983 and 2012, the age of the overall top ten finishers and the fastest swimmers, cyclists, and runners increased across years for both women and men (p < 0.01).ConclusionsTo summarize, for the overall top ten finishers, the sex difference decreased across years for overall race time and running, but not for swimming and cycling. For the top ten per discipline, the sex difference in performance remained unchanged. The athletes improved their performances across years although the age of peak performance increased.

Kinanthropometric differences between 1997 World championship junior elite and 2011 national junior elite triathletes

In 1997, anthropometry measures were made to determine the body size and shapes of both senior and junior elite triathletes. Since then, the junior event distance has changed and the optimal morphology of participants may have evolved. Thus the objective of this study was to compare the morphology of 1997 World championship junior elite triathlon competitors with junior elite competitors in 2011. Comparative study of junior elite triathlete kinanthropometry. Twenty-nine males and 20 females junior elite competitors in the 1997 Triathlon World Championships underwent 26 anthropometric measurements. Results were compared with 28 male and 14 female junior elite triathletes who competed in the 2011 Australian National Junior Series, as qualifying for 2011 Triathlon World Championships. Comparisons were made on the raw scores, as well as somatotype, and body proportional scores. Both male and female junior elite triathletes in the 2011 group were significantly more ectomorphic than their 1997 counterparts. The 2011 triathletes were also proportionally lighter, with significantly smaller flexed arm and thigh girths, and femur breadths. The 2011 males recorded significantly longer segmental lengths and lower endomorphy values than the 1997 junior males. Junior elite triathlete morphology has evolved during the past 14 years possibly as a result of changing race distance and race tactics, highlighting the importance of continually monitoring and updating such anthropometric data.

Differences in gender and performance in off-road triathlon

The aims of this study were: (1) to examine performance trends and compare elite male and female athletes at the off-road triathlon (1.5-km swim, 30-km mountain biking, and 11-km trail running) world championships since its inception in 1996, and (2) to compare gender-related differences between off-road triathlon and conventional road-based triathlon. Linear regression analyses and ANOVA were used to examine performance trends and differences between the sexes. Elite male performance times stabilized over the 2005–2009 period, whereas elite female performance times continued to improve, especially for the run leg. Differences in performance times between the sexes were less marked in swimming than in mountain biking and running, whereas differences in power output were more marked for mountain biking than for swimming and running. In addition, differences in cycling between the sexes were greater for off-road than conventional on-road triathlon. The specific aspects of mountain biking (e.g. level and terrain) may partly explain the significant differences between the sexes recorded in cycling for off-road triathlon. Future studies will need to focus on the physiological bases of off-road triathlon and how they differ from conventional triathlon.

Weight Changes among Athletes Presenting to the Medical Tent at the Ironman Triathlon World Championships

The Ironman Triathlon Championship in Kona, Hawaii is considered the toughest of all Ironman races due to extreme environmental conditions during the bike and run portions of the race. High heat and humidity lead to frequent problems with fluid and electrolyte balance among athletes presenting to the medical tent. PURPOSE: Evaluate weight changes among male and female competitors seen in the medical tent on race day at the 2008 Ironman Triathlon World Championship. METHODS: Medical tent records from the 2008 race were reviewed regarding changes between pre and post-race weights, among athletes seen in the medical tent. These changes in weight were correlated with age and gender of the competitors. RESULTS: 229 athletes were seen in the medical tent during last years race, including 150 males and 79 females. Of those athletes, 206 (136 men and 70 women) had pre and post-race weights recorded in their medical records. The average percent weight change for all men was -1.6 %, while the average weight change for all women was +.04 %. The maximum weight loss was -15.7 % in a male competitor and -9.8% in a female competitor. The maximum weight gain was +7.4% in a male competitor and +13.9% in a female competitor. In looking at age groups, the average weight change in men was -2.1% in those 20-30 yrs; -1.8% in men 31-40; -1.5% in men 41-50 and -0.4% in men older than 50. For age grouped females, the average weight change was +1.0% in those 20-30; +.5% in women 31-40; -1.1% in women 41-50 and +.5% in women older than 50. CONCLUSIONS: Based on this review, it appears men and women Ironman triathletes under the age of 40 yrs and over the age of 50 yrs seen in the medical tent have differing problems with fluid balance. Our data suggest women tend to over replace fluid losses and are more likely to gain weight during the race, while men are more likely to under replace fluid losses and lose weight. This pattern of over replacement of fluid loss did not seem to exist for females between the ages of 41 - 50 yrs, as they were the only aged group females not found to gain weight. We also found that younger men tended to under replace fluid compared to older men. Based on these results, consideration should be given to tailoring messaging on fluid intake to the gender and age of the Ironman Triathlete, with the exception noted for women between the ages of 40 - 50 yrs.

Correlating Medical Tent Visits, Hospital Admissions And Heat Index At The Ironman Triathlon World Championships

Correlating Medical Tent Visits, Hospital Admissions And Heat Index At The Ironman Triathlon World Championships

Well-Trained Endurance Athletes’ Knowledge, Insight, and Experience of Caffeine Use

This descriptive cross-sectional study assessed the perceptions, knowledge, and experiences of caffeine use by athletes competing at the 2005 Ironman Triathlon World Championships. Questionnaires were distributed to 140 athletes (105 men and 35 women, 40.3 +/- 10.7 y old) representing 16 countries during prerace registration. A large proportion (73%) of these endurance athletes believe that caffeine is ergogenic to their endurance performance, and 84% believe it improves their concentration. The most commonly reported positive caffeine experiences related to in-competition use of cola drinks (65%) and caffeinated gels (24%). The athletes' ability to accurately quantify the caffeine content of common food items was limited. The most popular sources of caffeine information were self-experimentation (16%), fellow athletes (15%), magazines (13%), and journal articles (12%). Over half the athletes (53%) could not identify an amount of caffeine required to improve their triathlon performance. Mean (+/- standard deviation) suggested doses were 3.8 (+/- 3) mg/kg body weight. Few side effects associated with taking caffeine during exercise were reported.

Awareness and Use of Caffeine by Athletes Competing at the 2005 Ironman Triathlon World Championships

This study assessed the knowledge, prevalence, and quantity of caffeine use by athletes competing at the 2005 Ironman Triathlon World Championships. Caffeine-related questionnaires were self-administered to 140 (105 male and 35 female, 40.3 +/- 10.7 y) athletes representing 16 countries. Fifty of these athletes further consented to immediate post-race blood samples for analysis of plasma caffeine and paraxanthine using high-performance liquid chromatography (HPLC). Seventy-two percent of 70 athletes correctly identified caffeine as being an unrestricted substance in triathlon. The majority of athletes [125 (89%)] were planning on using a caffeinated substance immediately prior to or throughout the race. Cola drinks (78%), caffeinated gels (42%), coffee (usually pre-race) (37%), energy drinks (13%), and NoDoz tablets (9%) were the most popular caffeinated choices. Mean +/- standard deviation (and range) post race plasma caffeine and paraxanthine levels were 22.3 +/- 20 micromol/L (1.7 to 98.4) and 9.4 +/- 6 micromol/L (1.8 to 28.9), respectively. Seven athletes (14%) finished with plasma caffeine levels > or = 40 micromol/L. Plasma values from elite athletes did not differ from age group competitors. Despite the prevalence of its consumption and the training experience of this athletic group, over one quarter of athletes remained either confused or uninformed about caffeine's legality. Levels of plasma caffeine taken immediately post race indicated that athletes typically finish with quantities of caffeine that have been shown to improve endurance performance (i.e., approximately 20 micromol/L or a dose of > or = 3 mg/kg body weight).

Sodium Balance And Sweat Loss During The Hawaii IRONMAN Triathlon

PURPOSE To determine the variability in sweating rate and sweat sodium concentration (sweat-Na) and its relationship to changes in serum sodium concentration (serum-Na) in ultra-endurance triathletes competing in the 2003 Ironman Triathlon World Championship. METHODS During the sweat analysis trial, seventy-one heat-acclimatized males and females (22–74y) exercised on a stationary bicycle at 70–75% of HRmax for 30 minutes following an 8 minute warm-up. All trials took place in warm conditions (26.4 ±0.2°CWBGT, 28.5 ± 0.2°C dry bulb, 66.0 ± 0.0% RH) in an outdoor field laboratory in Kailua-Kona, HI, 3–7d prior to the race. Serum-Na and skin-fold thickness were measured prior to exercise. Sweating rate, determined via change in body mass, and sweat-Na were measured during the 30 min exercise bout. Forty-six male and female subjects who participated in the sweating analysis trial were also studied on race-day. Pre- and post-race serum-Na and body mass were measured and race nutritional intake was also recorded. RESULTS The subjects exhibited a large amount of variability in absolute and relative sweating rate (1.39±0.05 L/hr, coefficient of variation (CV) = 30.8%; 19.4 ± 0.7 ml/kg/hr, CV = 28.5%), sweat-Na (43.4±2.1 mEq/L, CV = 40.0%), and absolute and relative sweat-Na loss(61.6±4.1 mEq/hr, CV = 56.0; 0.87 ± 0.06 mEq/kg/hr, CV = 54.2%). In males, the decline in race-day serum-Na was correlated with relative sweat rate, relative rate of sweat-Na loss, and body mass change (r=−0.413, p<0.05; r=−0.457, p<0.05; r=−0.549, p<0.01). Together, the rate of relative sweat-Na loss and body mass change were highly related to changes in serum-Na (r=0.686, p<0.05). In females, body mass changes alone were highly associated with declines in serum-Na (r=0.614, p<0.05). Females had a significant relationship between rate of absolute sweat-Na loss and Na intake (r=0.637, p<0.05), while males did not (r=0.280, p=0.466). CONCLUSIONS Changes in serum-Na during an ultra-endurance triathlon were related to the interactions of sweat-Na loss, sodium ingestion, and fluid balance. Supported by the Gatorade Sports Science Institute.

Sodium Balance And Sweat Loss During The Hawaii IRONMAN Triathlon

PURPOSE To determine the variability in sweating rate and sweat sodium concentration (sweat-Na) and its relationship to changes in serum sodium concentration (serum-Na) in ultra-endurance triathletes competing in the 2003 Ironman Triathlon World Championship. METHODS During the sweat analysis trial, seventy-one heat-acclimatized males and females (22–74y) exercised on a stationary bicycle at 70–75% of HRmax for 30 minutes following an 8 minute warm-up. All trials took place in warm conditions (26.4 ±0.2°CWBGT, 28.5 ± 0.2°C dry bulb, 66.0 ± 0.0% RH) in an outdoor field laboratory in Kailua-Kona, HI, 3–7d prior to the race. Serum-Na and skin-fold thickness were measured prior to exercise. Sweating rate, determined via change in body mass, and sweat-Na were measured during the 30 min exercise bout. Forty-six male and female subjects who participated in the sweating analysis trial were also studied on race-day. Pre- and post-race serum-Na and body mass were measured and race nutritional intake was also recorded. RESULTS The subjects exhibited a large amount of variability in absolute and relative sweating rate (1.39±0.05 L/hr, coefficient of variation (CV) = 30.8%; 19.4 ± 0.7 ml/kg/hr, CV = 28.5%), sweat-Na (43.4±2.1 mEq/L, CV = 40.0%), and absolute and relative sweat-Na loss(61.6±4.1 mEq/hr, CV = 56.0; 0.87 ± 0.06 mEq/kg/hr, CV = 54.2%). In males, the decline in race-day serum-Na was correlated with relative sweat rate, relative rate of sweat-Na loss, and body mass change (r=−0.413, p<0.05; r=−0.457, p<0.05; r=−0.549, p<0.01). Together, the rate of relative sweat-Na loss and body mass change were highly related to changes in serum-Na (r=0.686, p<0.05). In females, body mass changes alone were highly associated with declines in serum-Na (r=0.614, p<0.05). Females had a significant relationship between rate of absolute sweat-Na loss and Na intake (r=0.637, p<0.05), while males did not (r=0.280, p=0.466). CONCLUSIONS Changes in serum-Na during an ultra-endurance triathlon were related to the interactions of sweat-Na loss, sodium ingestion, and fluid balance. Supported by the Gatorade Sports Science Institute.

Ability, Age, and Performance

A person’s age is used in many ways in economic decisions due to the belief that it is a low cost proxy for ability. Even with this importance assigned to age, however, little economic research has investigated the underlying relationship between age and output. Our purpose is to consider this relationship using data from the Ironman Triathlon World Championship. Our findings indicate that men age faster than the rates estimated by others. Also, unlike other studies, these data allow inferences to be drawn about the linkage between age and ability for women. We find that women age only slightly faster than men, showing some relative increase in aging in later years. At younger ages, however, women appear more responsive to training and maturation (forms of human capital investment) than young men.

PRE-EXISTING MEDICAL PROBLEMS AMONG IRONMAN TRIATHLON WORLD CHAMPIONSHIPS ENTRANTS

An Ironman triathlon is a grueling test of an athlete's skill and endurance, involving a 2.4-mile swim, a 112-mile bike and a 26.2-mile run. The 2001 Ironman Triathlon World Championships in Kona, Hawaii involved 1,518 entrants who ranged in age from 19 to 78. Knowledge of common pre-existing medical conditions would be helpful to race medical staff in planning for potential complications, and in advising patients with medical problems who are contemplating participation in such a strenuous event. PURPOSE: To determine common pre-existing medical problems among Ironman entrants. METHODS: We reviewed the medical data from each participant's pre-race questionnaire to ascertain the types and frequency of medical problems among this year's entrants. RESULTS: Of the 1,518 entrants, only 102 (6.7%) reported pre-existing medical problems. The most common reported problems were asthma or EIA (37), allergic rhinitis (12), hypothyroidism (10), hypercholesterolemia (6), gastroesophageal reflux disease (GERD) (5), and hypertension (6). Several entrants disclosed more serious chronic diseases including atrial fibrillation (2), Crohn's disease (2), lymphoma (2), diabetes (1), epilepsy (1), and cystic fibrosis (1). Additionally, 25 entrants (1.7%) reported a pre-existing physical condition. The most common were recent fractures (within a year) (3), below the knee amputation (2), paraplegia (2) and a single kidney (2). Additionally, 43 athletes reported a history of hypersensitivity to bee's, wasps, or jellyfish. Only 86 entrants (5.7%) reported significant problems associated with past triathlon races, the most common of which were dehydration (57), hyponatremia (10), and heat exhaustion (3). CONCLUSIONS: Based on our review, it is clear that entrants into the Ironman Triathlon World Championships represent a healthy cohort of athletes, however a small percentage compete despite a history of serious medical and physical conditions.

Ultraviolet exposure in the Ironman triathlon.

Skin cancer is increasing worldwide and exposure to ultraviolet (UV) radiation is thought to be the most important environmental risk factor. People practicing outdoor sports are exposed to considerable amounts of UV radiation from the sun. Three triathletes participated in the Ironman Triathlon World Championships 1999 in Hawaii (3.9-km swim, 180.2-km bike, 42.4-km run). They attached Bacillus subtilis spore film dosimeters (VioSpor) on the back between their shoulders. The dosimeter system measured cumulative biologically weighted erythemal UV exposure. UV exposure is given in minimal erythema doses (1 MED corresponds to 250 J x m(-2) at 298 nm). The mean personal UV exposure was 8.3 MED (6.9--9.7 MED) after 8:43 to 9:44 h of competition corresponding to 0.8 to 1.3 MED x h(-1) (bike and run). The athletes were sunburned despite the use of water-resistant sunscreen (SPF 25+) on sun exposed skin. The International Radiation Protection Agency has issued guidelines for professional UV exposure. Ironman triathletes considerably exceeded these limits of exposure similar to other outdoor sports. Professional and amateur athletes should be aware of hazards caused by UV radiation. Adequate protection by water-resistant sunscreens and clothing as well as training and competition schedules with low sun exposure seem to be a reasonable recommendation.

Triathlons-Not Just for Ironmen.

Although they seem to call for inhuman strength and endurance, triathlons are not just for Ironmen: Women and seniors are also competitors in the event. But as the remarkably high completion rate of the Iron-man Triathlon World Championship would suggest, there may be something in the event itself that increases the likelihood of success.

Hemolysis during triathlon races: its relation to race distance.

Ninety-five triathletes were evaluated for evidence of hemolysis during triathlon races of two different distances. Thirty competitors (11 males, 19 females) were studied before and after the United States Triathlon Series (USTS) National Championship Race (1.5K swim, 40K bike, and 10K run). Pre- and post-race venous blood samples showed that 93% of the USTS athletes had decreased serum haptoglobin, post-race (mean decrease = 20%). Seven of 30 of the USTS triathletes (3 males, 4 females) were found to have occult blood in their urine, post-race. Only two of the USTS triathletes (1 male, 1 female) were anemic as judged by pre-race hemoglobin levels. Similar data were collected on 65 triatheletes (46 males, 19 females) at the Hawaii IRONMAN Triathlon World Championship (3.9K swim, 180.2K bike, and 42.2K run). Pre- and post-race venous blood samples showed that 95% of the IRONMAN athletes had decreases in serum haptoglobin, post-race (mean decrease = 32%). Occult blood was found in the post-race urine of 19 (12 males, 7 females) of the IRONMAN competitors. Nineteen IRONMAN triathletes (18 males, 1 female) were judged to be anemic from pre-race hemoglobin measurements. Data from two different length triathlons suggest that nearly all triathletes break down red blood cells during a race, and that the extent of the hemolysis is related to race distance.

Hyponatremia and Ultramarathons

To the Editor.— We read with great interest the article by Frizzell et al1in the Feb 14 issue ofJAMA. We are certainly in agreement with the authors concerning the serious nature of hyponatremia in ultraendurance athletes in whom hyponatremia is a real and potentially life-threatening problem. In our prospective study2in 1984 at the Ironman Triathlon World Championship in Hawaii, we were very surprised to find hyponatremia in 29% of the study subjects. However, we would like to differ with one major point made in the Frizzell article and in the article by Noakes et al3to which the authors refer. It was postulated by both Frizzell et al and Noakes et al that these hyponatremic athletes were overhydrated. The only direct evidence in support of this is the weight gain of one athlete (a 4.5-kg gain by case 4 in the Noakes et al

Triathlete characterization and response to prolonged strenuous competition

The purpose of this study was to characterize triathletes and to assess their responses to prolonged, strenuous competition. Nine triathletes (6 males, 3 females) participated. Mean V0(2)max and percentage of body fat were 72.0 ml X kg-1 X min-1 and 7.1%, respectively, in the four males who finished in the top 15. This compared to values of 58.4 ml X kg-1 X min-1/10.2% and 58.7 ml X kg-1 X min-1/12.6% in the other males and females, respectively. In the 5 wk preceding competition (Hawaii "Ironman Triathlon World Championship") the average daily training of the four top 15 male competitors consisted of swimming 2720 m, running 13.6 km, and biking 84.0 km. This was approximately 1.5 times greater than that of the other athletes. The average training diet was 59% carbohydrate, 21% fat, and 20% protein. Immediately following competition, SGOT, SGPT, and serum LDH were increased 700, 262, and 222% (P less than 0.004), respectively, and still remained marginally elevated 5-6 d later (P less than 0.02). Immediately following competition, serum triglycerides remained unchanged, while serum glucose, glycerol, and nonesterified fatty acids increased 52, 248, and 191% (P less than 0.005), respectively. By 5-6 d post-competition glucose had returned to normal, while triglycerides were elevated 94% (P less than 0.005) and nonsterified fatty acids were decreased 58% (P less than 0.01).