Effect of ENDUROX™ on Metabolic Responses to Submaximal Exercise

Claims that ENDUROX™ enhances performance by altering metabolic responses to exercise were tested. In a double-blind crossover design, 10 male subjects were randomly assigned to consume 400 mg of placebo or 800 mg ENDUROX™ for 7 days. Cycle ergometry was performed for 30 minutes at 25%, followed by 10 min at 65% of peak oxygen consumption. After a 1-week washout period, subjects performed the identical exercise protocol following 7 days of reciprocal supplemental conditions. Expired gases were collected and analyzed continuously for oxygen consumption, minute ventilation, and respiratory exchange ratio. Heart rate, blood pressure, rating of perceived exertion, blood lactate, and serum glycerol data were also collected at regular intervals. A two-way ANOVA with repeated measures revealed no significant main or interaction effects involving group differences (p > 0.05) between trials for any variable during rest, 25% or 65% (VO2 peak), or recovery. Our findings do not support the ergogenic claims for ENDUROX™.

A Report of Vitamin and Mineral Supplement Use among University Athletes in a Division I Institution

The influences of gender, ethnicity, and sport of varsity athletes on their vitamin/mineral supplementation habits were examined. Subjects included 145 females and 266 males from 22 varsity teams; 80% were Caucasian; 12% African American; and 8% Combined-Other. Over half of the subjects took supplements. Males were more likely than females to give "too expensive" as a reason for not taking supplements, and "improve athletic performance" and "build muscle" as reasons for taking supplements. The most common supplement was multivitamins plus minerals. Females were more likely to take calcium and iron, and males vitamins B 12 and A. African Americans were the most likely to take vitamin A. Males were more likely to get supplement information from nutritionists/dietitians and self, and females from family members or friends and physicians or pharmacists. Football players were more likely to get supplement information from nutritionists/dietitians, and males in other sports from coaches/trainers. There were some differences in vitamin/mineral supplement habits of the athletes by gender, ethnicity, and sport.

Nutritional and Physiological Status of U.S. National Figure Skaters

This study assessed the nutrient intake, body composition and biochemical indices of National Figure Skating Championship competitors. Four-day diet records, fasting blood samples, and anthropometric measurements were obtained 2 months after the National Championships from 41 figure skaters 11-18 years of age. Energy, carbohydrate, fat, dietary fiber and cholesterol intake were significantly lower compared to the NHANES III averages for adolescents in the U.S. In general, the mean intakes for most vitamins except vitamin D and E were above the recommended intake. But the athletes had lower intakes of vitamin E and B12, and higher intakes of vitamin C, and thiamin (females only) compared with NHANES III. The mean intakes of magnesium, zinc, and iodine by the male skaters were below the recommended levels, as were the mean intakes of calcium, iron, phosphorus, magnesium, and zinc by the female skaters. Also, the number of servings from vegetable, fruit, dairy, and meat groups were below the recommended levels. Biochemical indices of nutritional status were within normal limits for all skaters. But plasma electrolyte concentrations were indicative of potential dehydration status. The results suggest there is a need to develop dietary intervention and educational programs targeted at promoting optimal nutrient and fluid intakes by these athletes to maintain performance and improve long-term health status.

Inosine Supplementation Has No Effect on Aerobic or Anaerobic Cycling Performance

The two basic aims of this study were to add to the limited literature concerning Inosine as an ergogenic aid, and to determine the effects of Inosine supplementation over a period of 5 and 10 days, at a dosage of 10,000 mg · d−1 on measures associated with aerobic and anaerobic performance. Seven trained, volunteer male subjects (body mass = 63.0 ± 8.7 kg, VO2max = 61.9 + 3.3 ml ⋅ kg−1 ⋅ min−1) participated in this study. The subjects completed three test sessions, each comprising three tests (5 × 6-s sprint, 30-s sprint, and 20-min time trial). Supplementation was carried out in a random, double-blind manner, and the test sessions were undertaken prior to (Baseline, B), on Day 6, and on Day 11. Blood was sampled prior to supplementation as well as on Days 6 and 11 and was analyzed for uric acid and 2,3 DPG. An analysis of the data indicated no performance benefit of supplementation and no improvement in 2,3 DPG concentration. Uric acid concentration increased significantly after both Days 6 and 11 (p < 0.03 and p < 0.004, respectively). It is concluded that Inosine has no ergogenic effects but may cause possible health problems if taken over long periods of time.

Resting Metabolic Rate and Thermogenic Effect of Glucose in Trained and Untrained Girls Age 11-15 Years

Twelve girls who trained in rowing were examined twice a year for 4 years. Their initial age was 11.7 ± (SD) 0.2 yrs. Control groups consisted of 13 girls age 11.5±0.3 yrs and 18 girls age 14.4±0.3 yrs examined simultaneously with trained girls in the first and last year of the study, respectively. The examination involved basic anthropometry, estimation of sexual maturation (Tanner scale), 2-day food records, measurements of resting metabolic rate, energy expenditure following glucose ingestion (50 g), and determinations of blood glucose and plasma insulin concentrations prior to and 2 hrs after glucose load. Body mass, height, and fat content were slightly greater in trained girls. None of the subjects reported disturbances in menstrual function, and the age of menarche was similar for all. Both trained and untrained girls reported similar daily energy intake closer to the lower limit or slightly below the estimates of energy requirements for adolescents. Resting metabolic rate calculated per kg of total body mass or lean body mass was lower in trained girls, while the thermogenic effect of glucose was greater. Plasma insulin concentrations measured 2 hrs after glucose ingestion were lower in trained girls. The results suggest that in circumpubertal girls, increased physical activity leads to energy conservation at rest in postabsorptive state and a tendency toward enhancement of food-induced thermogenesis.

Influence of Caffeine on Metabolic and Cardiovascular Functions during Sustained Light Intensity Cycling and at Rest

This study assessed the influence of caffeine on metabolic and cardiovascular functions during sustained, light intensity cycling and at rest. Eight healthy, recreationally active adults participated in four randomly assigned, double-blind experimental trials of 60 min upright seated cycle exercise (30% VO2max) or equivalent rest with caffeine (5 mg ⋅ kg−1) or placebo consumed 60 min prior to data collection. Gas exchange was measured by open-circuit spirom-etry indirect calorimetry. Global blood flow was evaluated by thoracic impedance cardiography and arterial blood pressure by auscultation. A repeated measures ANOVA indicated that pretrial caffeine increased oxygen uptake and energy expenditure rate (p < 0.05) but did not change respiratory exchange ratio. Systolic, diastolic, and mean arterial blood pressure were elevated following caffeine intake (p < 0.05). Cardiac output, heart rate, stroke volume, and systemic vascular resistance were not significantly different between caffeine and placebo sessions. For each of the metabolic and hemodynamic variables examined, the effects of caffeine were similar during constant-load, light intensity cycling and at rest. These data illustrate that caffeine's mild thermogenic influence can be mediated without a major shift in substrate oxidation mixture. Caffeine at this dosage level alters cardiovascular dynamics by augmenting arterial blood pressure.

Glycogen Replenishment and Repeated Maximal Effort Exercise: Effect of Liquid Carbohydrate

We investigated the effects of carbohydrate ingestion on glycogen replenishment and subsequent short duration, high intensity exercise performance. During Session 1, aerobic power was determined and each subject (N = 6) was familiarized with the 100-kJ cycling test (lOOKJ-Test). During the treatment sessions, the subjects performed a lOOKJ-Test (Ride-1), then consumed 0.7 g ⋅ kg body mass-1 of maltodextrin (CHO) or placebo (PLC), rested 60 min, and then performed a second lOOKJ-Test (Ride-2). Muscle tissue was collected before (Pre-1) and after Ride-1 (Post-1), and before (Pre-2) and after Ride-2 (Post-2), and analyzed for glycogen concentration. Both treatments yielded a significant increase in glycogen levels following the 60-min recovery, but there was no difference between treatments. Time to complete the lOOKJ-Test increased significantly for PLC, but not for CHO. These data indicate that the decrease in performance during Ride-2 in PLC was not the result of a difference in glycogen concentration.

Ginseng Treatment Improves Psychomotor Performance at Rest and During Graded Exercise in Young Athletes

This study was designed to determine the effect of ginseng treatment on multiple choice reaction time (RT) during exercise. Fifteen soccer players (age 19.07 ± 0.62 yrs) were placed in a double-blind manner into one of two groups: ginseng (n = 7), receiving 350 mg of ginseng daily for 6 weeks, or placebo (n = 8), receiving a placebo daily for 6 weeks. Before and after the treatment all the subjects performed an incremental bicycle ergometer exercise with intensity increasing 50 W every 3 min until volitional exhaustion. RT was measured before exercise, and then in the last 2 min of each exercise load. Maximal oxygen uptake (VO2max) and lactate threshold (LAT) were also determined from the exercise test. Ginseng treatment was found to shorten RT at rest and during exercise, shifting the exercise load associated with the shortest RT toward higher exercise loads. Neither ginseng nor placebo influenced VO2 max and LAT. In conclusion, ginseng extract does improve psychomotor performance during exercise without affecting exercise capacity.

Acute Carbohydrate Consumption Does Not Influence Resistance Exercise Performance during Energy Restriction

The effect of acute carbohydrate consumption on performance and metabolism of resistance-trained males was determined. Twenty-two subjects, assigned to either carbohydrate (C, n = 8), placebo (P, n - 8), or control (N, n = 6), performed standardized workouts every other day for a week prior to testing and throughout the testing period. Three of these workouts (Tl, T2, and T3) were the performance test in that the last bouts of leg extension and bench press were done to failure at 80% of 10 repetition maximum. A carbohydrate or placebo beverage was consumed 30 min prior to T3. Blood samples were drawn before and after T2 and T3. There was no effect of carbohydrate or energy restriction on number of repetitions done during the leg extension performance test. Carbohydrate intake prior to a resistance exercise bout done in negative energy balance state did not affect performance or evidence of muscle damage.

Patterns of Vitamin/Mineral Supplement Usage by Adolescents Attending Athletic High Schools in Korea

An excessive use of vitamin/mineral supplements is considered by many to be a common health problem. We surveyed 1,355 adolescent boys and girls attending athletic high schools in Korea for their usage patterns of vitamin/mineral supplements. The usage rate of the vitamin/mineral supplements was 35.8%. The most favored supplements were vitamin C, multivitamins, and calcium. The reasons most cited for taking supplements were "to recover from fatigue," and "to maintain health." Vitamin and mineral intakes occurred over a wide range; mean intake values were typically higher than the Korean RDA. Vitamins B , B12 and C were consumed in very high amounts at 29.7,17.9 and 11.1 times the Korean RDA, respectively. When the intakes of nutrients from supplements and diet were combined, it was observed that the intakes of niacin, folic acid, vitamin C, and iron exceeded levels that have been proposed as upper safe limits. The above data underscore the need to provide sound nutritional education to athletic adolescents and their coaches with respect to the use of vitamin/ mineral supplements and the links between adequate diet, good health, and physical performance.