Author: Peters EM; Goetzsche JM
Address: Division of Physical Education, Witwatersrand University, Johannesburg, South Africa.
Source: Int J Sport Nutr, 7(2):80-103 1997 Jun
Training (T) and prerace (PR) dietary intakes of male and female athletes participating in a 90-km ultramarathon and the usual diets of matched, sedentary controls were investigated using 24-hr dietary records. Supplement use, mean weekly training distance, and race performance times were recorded. Macro- and micronutrient intakes were analyzed using computerized nutritional analysis programs. Total mean energy intake in the T and PR diets of the runners was 10.1 and 12.8 MJ in the men (n = 150) and 7.5 and 9.1 MJ in the women (n = 23). Mean relative contribution of CHO to the runners' total kilojoule intake increased from 50.0 and 49.5% in the T diets to 57.7 (p < .05; n = 153) and 56.4% (p < .05; n = 23) in the PR diets of male and female runners, respectively, and energy-boosting supplements were included in the PR diets of 48% of female and 59% of male runners. Seventy-eight percent of female and 62% of male runners used vitamin and mineral supplements in their T diets as opposed to 39% of female and 28% of male controls. No statistically significant relationship was found between total kilojoule, CHO, fat, protein, and selected micronutrient intake during the 3 days before the race and performance in the 90-km event in runners of homogenous training status and gender.
Submitted by Rich Schick
Author: Kolkhorst FW; MacTaggart JN; Hansen MR
Address: School of Health, University of Northern Iowa, Cedar Falls 50614-0241, USA
Source: Can J Appl Physiol, 23(3):271-8 1998 Jun
The manufacturer claims that using the Access Fat Conversion Activity Bar increases fat utilisation, which would have a glycogen-sparing effect and delay the onset of fatigue from endurance exercise. This claim was tested using seven trained distance runners who performed two trials of treadmill running at 73% of VO2max to exhaustion. In a counterbalanced design, subjects ingested either one Access Bar with water or water only prior to treadmill running. Times to exhaustion for the control and Access treatment trials were 104.6 +/- 24.9 min and 93.9 +/- 21.4 min, respectively, and were not significantly different (p > .05). Differences between trials were not observed for the respiratory exchange ratio, blood lactate or glucose concentrations, plasma glycerol concentration, or perceived exertion. Based on results from this study, it was concluded that the Access Bar does not affect fat or carbohydrate utilisation and does not improve exercise endurance. Language
Submitted by Rich Schick
Author: Fallon KE; Broad E; Thompson MW; Reull PA
Address: Department of Sports Medicine, Australian Institute of Sport, Canberra, Australia.
Source: Int J Sport Nutr, 8(1):24-35 1998 Mar
The fluid and food intakes of 7 male participants in a 100-km ultramarathon were recorded. The mean exercise time was 10 hr 29 min. Nutrient analysis revealed a mean intrarace energy intake of 4,233 kJ, with 88.6% derived from carbohydrate, 6.7% from fat, and 4.7% from protein. Fluid intake varied widely, 3.3-11.1 L, with a mean of 5.7 L. The mean decrease in plasma volume at 100 km was 7.3%, accompanied by an estimated mean sweat rate of 0.86 L.hr-1. Blood glucose concentrations remained normal during the event, and free fatty acids and glycerol were elevated both during and at the conclusion of the event. No significant correlations were found between absolute amounts and rates of ingestion of carbohydrate and/or fluid and race performance.
Submitted by Rich Schick
Author: Gastmann U; Dimeo F; Huonker M; Bšocker J; Steinacker JM; Petersen KG; Wieland H; Keul J; Lehmann M
Address: Department of Sports Medicine, University Medical Hospital Freiburg, Germany
Source: J Sports Med Phys Fitness, 38(1):18-23 1998 Mar
BACKGROUND: Objective of this study was to get more insight in hematology, biochemistry, and endocrinology of ultra-endurance exercise, to improve knowledge in this field, supplementation, and medical care of affected athletes.
METHODS: A large body of individual hematological, biochemical, and endocrinological parameters was analyzed in the blood taken from ultra- athletes before and after completing the 1993 Colmar ultra triathlon covering 7.5 km swimming, 360 km cycling, and approximately 85 km running.
PARTICIPANTS: Nine experienced ultra-athletes participated in the study. A follow-up was not possible since the athletes left Colmar within 24 hrs after the contest.
RESULTS: The athletes finished the ultra-contest at rankings 4, 5, 7, 8, 9, 11, 18, 22, 23 in a total time between 23:38:53 and 27:54:30 hr:min:sec. Their final body mass (68.6 +/- 1 kg) was significantly lower than at baseline (71.9 +/- 4.2 kg). None of the athletes made use of medical care. Data after this contest reflect mild hyponatremia, intravascular hemolysis, increased triglyceride turnover, acute-phase reaction, hyperaldosteronemia 2061 +/- 1013 pmol.L-1), hypercortisolemia 971 +/- 486 nmol.L-1), hyper- growth-hormonemia (median 6.8 ng.ml-1), hypoinsulinemia, hypo-free- testosteronemia (42 +/- 17 pmol.L-1), protein catabolism, depressed testicular function, oliguria, and muscle cell leakage.
CONCLUSIONS: In our opinion, data presented do not reflect any acute health risks in healthy athletes who are well prepared and carefully supplied during such a contest.