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David R. Hooper, William J. Kraemer, Rebecca L. Stearns, Brian R. Kupchak, Brittanie M. Volk, William H. DuPont, Carl M. Maresh and Douglas J. Casa

in duration, an ironman event combines a 2.4-mile swim and 112-mile bike ride with a traditional 26.2-mile marathon distance run. Competitors in such a race have also demonstrated substantially reduced testosterone concentrations, with an average testosterone of 11.4 nmol·L −1 (329 ng·dL −1 ). 16 In

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Ed Maunder, Andrew E. Kilding, Christopher J. Stevens and Daniel J. Plews

, the beneficial observed thermoregulatory 9 and hypothesized metabolic 1 adaptations should be balanced against potential risks to athlete well-being. The purpose of this case study is therefore to describe how a real-world heat stress training camp undertaken by 2 highly trained Ironman triathletes

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Hani Kopetschny, David Rowlands, David Popovich and Jasmine Thomson

Athletes aiming to compete in long-distance triathlons (e.g., ironman and half-ironman) frequently undertake high volumes of endurance exercise training to enhance performance. The intensity and volume of training is commonly periodized with concomitant high but fluctuating calorie expenditure

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Claire Blennerhassett, Lars R. McNaughton, Lorcan Cronin and S. Andy Sparks

. PubMed ID: 20601743 doi:10.1123/ijsnem.20.3.257 10.1123/ijsnem.20.3.257 Kimber , N.E. , Ross , J.J. , Mason , S.L. , & Speedy , D.B. ( 2002 ). Energy balance during an ironman triathlon in male and female triathletes . International Journal of Sports and Exercise Metabolism, 12 , 47 – 62

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Jason Youngman and Duncan Simpson

Researchers have noted that when taken to an excessive level, exercise may become addictive. This study investigated the risk of exercise addiction for triathletes using the Exercise Addiction Inventory (EAI; Terry, Szabo, & Griffths, 2004). The sample consisted of 1,285 male and female triathletes, ranging in age from 18–70 years old. Results indicated that approximately 20% of triathletes are at risk for exercise addiction, and that training for longer distance races (i.e., Olympic, Half-Ironman, and Ironman) puts triathletes at greater risk for exercise addiction than training for shorter races (i.e., Sprint). No significant association was found between the risk for exercise addiction and the number of years of participating. However, as the number of weekly training hours increased, so did a triathlete’s risk for exercise addiction. At-risk triathletes need greater clinical attention, and further research should be conducted to help clinicians develop awareness and appropriate interventions.

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Catriona A. Burdon, Nathan A. Johnson, Phillip G. Chapman, Ahmad Munir Che Muhamed and Helen T. O’Connor

Purpose:

The aim of this study was to measure the effect of environmental conditions and aid-station beverage-cooling practices on the temperature of competitor beverages.

Methods:

Environmental and beverage temperatures were measured at three cycling and two run course aid stations at the 2010 Langkawi, Malaysia (MA), and Port Macquarie, Australia (AU), Ironman triathlon events. To measure the specific effect of radiant temperature, additional fluid-filled (600 ml) drink bottles (n = 12) were cooled overnight (C) and then placed in direct sun (n = 6) or shade (n = 6) near to a cycle aid station at AU.

Results:

During both events, beverage temperature increased over time (p < .05) as environmental conditions, particularly radiant temperature increased (p < .05). Mean beverage temperature ranged between 14–26°C and during both events was above the palatable range (15–22°C) for extended periods. At AU, bottles placed in direct sunlight heated faster (6.9 ± 2.3 °C·h−1) than those in the shade (4.8 ± 1.1°C·h−1, p = .05).

Conclusion:

Simple changes to Ironman aidstation practices, including shade and chilling beverages with ice, result in the provision of cooler beverages. Future studies should investigate whether provision of cool beverages at prolonged endurance events influences heat-illness incidence, beverage-consumption patterns, and competitor performance.

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John S. Cuddy, Dustin R. Slivka, Walter S. Hailes, Charles L. Dumke and Brent C. Ruby

Purpose:

The purpose of this study was to determine the metabolic profile during the 2006 Ironman World Championship in Kailua-Kona, Hawaii.

Methods:

One recreational male triathlete completed the race in 10:40:16. Before the race, linear regression models were established from both laboratory and feld measures to estimate energy expenditure and substrate utilization. The subject was provided with an oral dose of 2H2 18O approximately 64 h before the race to calculate total energy expenditure (TEE) and water turnover with the doubly labeled water (DLW) technique. Body weight, blood sodium and hematocrit, and muscle glycogen (via muscle biopsy) were analyzed pre- and postrace.

Results:

The TEE from DLW and indirect calorimetry was similar: 37.3 MJ (8,926 kcal) and 37.8 MJ (9,029 kcal), respectively. Total body water turnover was 16.6 L, and body weight decreased 5.9 kg. Hematocrit increased from 46 to 51% PCV. Muscle glycogen decreased from 152 to 48 mmoL/kg wet weight pre- to postrace.

Conclusion:

These data demonstrate the unique physiological demands of the Ironman World Championship and should be considered by athletes and coaches to prepare sufficient nutritional and hydration plans.

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Trevor L. Gillum, Charles L. Dumke and Brent C. Ruby

Purpose:

To describe the degrees of muscle-glycogen depletion and resynthesis in response to a half Ironman triathlon.

Methods:

One male subject (38 years of age) completed the Grand Columbian half Ironman triathlon (1.9-km swim, 90-km bike, 21.1-km run, Coulee City, Wash). Three muscle biopsies were obtained from his right vastus lateralis (prerace, immediately postrace, and 4 hours postrace). Prerace and postrace body weight were recorded, in addition to macronutrient consumption before, during, and after the race. Energy expenditure and whole-body substrate oxidation were estimated from linear regression established from laboratory trials (watts and run pace relative to VO2 and VCO2).

Results:

Body weight decreased 3.8 kg from prerace to postrace. Estimated CHO energy expenditure was 10,003 kJ for the bike segment and 5759 kJ for the run segment of the race. The athlete consumed 308 g of exogenous CHO (liquid and gel; 1.21 g CHO/min) during the race. Muscle glycogen decreased from 227.1 prerace to 38.6 mmol · kg wet weight−1 · h−1 postrace. During the 4 hours postrace, the athlete consumed a mixed diet (471 g CHO, 15 g fat, 64 g protein), which included liquid CHO sources and a meal. The calculated rate of muscle-glycogen resynthesis was 4.1 mmol · kg wet weight−1 · h−1.

Conclusion:

Completing a half Ironman triathlon depends on a high rate of muscle glycogenolysis, which demonstrates the importance of exogenous carbohydrate intake during the race. In addition, rates of muscle-glycogen resynthesis might be dampened by the eccentric damage resulting from the run portion of the race.

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Iker Muñoz, Roberto Cejuela, Stephen Seiler, Eneko Larumbe and Jonathan Esteve-Lanao

Purpose:

To describe training loads during an Ironman training program based on intensity zones and observe training–performance relationships.

Methods:

Nine triathletes completed a program with the same periodization model aiming at participation in the same Ironman event. Before and during the study, subjects performed ramp-protocol tests, running, and cycling to determine aerobic (AeT) and anaerobic thresholds (AnT) through gas-exchange analysis. For swimming, subjects performed a graded lactate test to determine AeT and AnT. Training was subsequently controlled by heart rate (HR) during each training session over 18 wk. Training and the competition were both quantified based on the cumulative time spent in 3 intensity zones: zone 1 (low intensity; <AeT), zone 2 (moderate intensity; between AeT and AnT), and zone 3 (high intensity; >AnT).

Results:

Most of training time was spent in zone 1 (68% ± 14%), whereas the Ironman competition was primarily performed in zone 2 (59% ± 22%). Significant inverse correlations were found between both total training time and training time in zone 1 vs performance time in competition (r = –.69 and –.92, respectively). In contrast, there was a moderate positive correlation between total training time in zone 2 and performance time in competition (r = .53) and a strong positive correlation between percentage of total training time in zone 2 and performance time in competition (r = .94).

Conclusions:

While athletes perform with HR mainly in zone 2, better performances are associated with more training time spent in zone 1. A high amount of cycling training in zone 2 may contribute to poorer overall performance.

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Nicholas E. Kimber, Jenny J. Ross, Sue L. Mason and Dale B. Speedy

Energy balance of 10 male and 8 female triathletes participating in an Ironman event (3.8-km swim, 180-km cycle, 42.2-km run) was investigated. Energy intake (EI) was monitored at 7 designated points by dietary recall of food and fluid consumption. Energy expenditure (EE) during cycling and running was calculated using heart rate-V̇O2 regression equations and during swimming by the multiple regression equation: Y = 3.65v + 0.02 W − 2.545 where Y is V̇O2 in L · min−1, v is the velocity in m · s−1, Wis the body weight in kilograms. Total EE (10.036 ± 931 and 8570 ± 1014 kcal) was significantly greater than total El (3940 ± 868 and 3115 ± 914kcal, p < .001) formales and females, respectively, although energy balance was not different between genders. Finishing time was inversely related to carbohydrate (CHO) intake (g · kg−1 · h−1) during the marathonrun formales (r=−.75, p < .05), and not females, suggesting that increasing CHO ingestion during the run may have been a useful strategy for improving Ironman performance in male triathletes.