Biomedical subjects

Alan C Utter

Publications and source records attributed to Alan C Utter.

24 records · Page 2Linked to original sources

PubMed2002

Children's OMNI Scale of Perceived Exertion: walking/running evaluation.

PURPOSE: The Children's OMNI-walk/run Scale of Perceived Exertion (category range, 0-10) was evaluated using male and female children (6-13 yr of age) during a treadmill graded exercise test. METHODS: A cross-sectional, perceptual estimation paradigm using a walking/running test protocol was administered. Oxygen uptake (VO(2), mL x min(-1)), %VO(2max), ventilation (VE, L x min(-1)), respiratory rate (RR, breaths x min(-1)), respiratory exchange ratio (RER), heart rate (HR, beats x min(-1)), V(E)/VO(2) ratio, and ratings of perceived exertion (RPE) measurements were made every minute throughout the test. RESULTS: Significant correlations were found between OMNI-walk/run Scale RPE responses and VO(2), %VO(2max), HR, V(E)/VO(2) ratio, and RR throughout the maximal treadmill exercise test. The strongest correlations were found between RPE and %VO(2max) (r = 0.41-0.60, P < 0.001) and HR (r = 0.26-0.52, P < 0.01). CONCLUSION: The psychophysiological responses provide validity evidence for use of the Children's OMNI-walk/run Scale over a wide range of exercise intensities during both walking and running.

Adolescent↗

PubMed2002

Effect of carbohydrate ingestion on ratings of perceived exertion during a marathon.

PURPOSE: The purpose of this study was to investigate the effects of carbohydrate substrate availability on ratings of perceived exertion (RPE) and hormonal regulation during a competitive marathon. METHODS: A randomized, double-blind study design was used in which subjects ran the marathon, and every 3.2 km, RPE and heart rate were measured. The marathoners were randomly assigned to receive carbohydrate (C) (N = 48) or placebo (P) (N = 50) beverages at a rate of 1 L x h(-1) during the race. RESULTS: Heart rate (%(HRMAX) ) was lower in P (82.0% +/- 0.6) than C (84.2% +/- 0.6) (P < 0.01), especially during the final 10 km: (78.7% +/- 1.0) and (84.5% +/- 0.7), respectively (P < 0.001). RPE was not significantly different between P and C throughout the marathon (P = 0.08) or during the final 10 km: (16.8 +/- 0.3) and (16.1 +/- 0.3), respectively (P = 0.06). Postrace plasma glucose (P < 0.001), insulin (P < 0.001), and lactate (P < 0.05) levels were significantly lower in P than C, and postrace cortisol (P < 0.05) significantly higher in P compared with C. CONCLUSIONS: Marathoners ingesting carbohydrate compared with placebo beverages were able to run at a higher intensity while reporting a nonsignificant difference in RPEs during a competitive race.

Adult↗

PubMed2002

Influence of vitamin C supplementation on oxidative and immune changes after an ultramarathon.

The purpose of this randomized study was to measure the influence of vitamin C (n = 15 runners) compared with placebo (n = 13 runners) supplementation on oxidative and immune changes in runners competing in an ultramarathon race. During the 7-day period before the race and on race day, subjects ingested in randomized, double-blind fashion 1,500 mg/day vitamin C or placebo. On race day, blood samples were collected 1 h before race, after 32 km of running, and then again immediately after race. Subjects in both groups maintained an intensity of approximately 75% maximal heart rate throughout the ultramarathon race and ran a mean of 69 km (range: 48-80 km) in 9.8 h (range: 5-12 h). Plasma ascorbic acid was markedly higher in the vitamin C compared with placebo group prerace and rose more strongly in the vitamin C group during the race (postrace: 3.21 +/- 0.29 and 1.28 +/- 0.12 microg/100 microl, respectively, P < 0.001). No significant group or interaction effects were measured for lipid hydroperoxide, F2-isoprostane, immune cell counts, plasma interleukin (IL)-6, IL-10, IL-1-receptor antagonist, or IL-8 concentrations, or mitogen-stimulated lymphocyte proliferation and IL-2 and IFN-gamma production. These data indicate that vitamin C supplementation in carbohydrate-fed runners does not serve as a countermeasure to oxidative and immune changes during or after a competitive ultramarathon race.

Administration, Oral↗

PubMed2002

Physiological profile of an elite freestyle wrestler preparing for competition: a case study.

The purpose of the present investigation was to describe the physiological changes of a nationally ranked older elite freestyle wrestler during a 7-month observation period as he prepared for the 2000 Olympic freestyle wrestling trials. A 33-year-old male wrestler was evaluated 3 times during the study for measurements of body composition, resting energy expenditure, maximal oxygen consumption, isometric strength, anaerobic power and capacity, nutritional intake, and various serum plasma constituents. Body weight decreased by 1 kg, which consisted of fat-free mass (FFM), whereas body fat remained stable at 5.8%. Muscular strength and aerobic power were maintained throughout the study. Measures of anaerobic work capacity tended to be higher and blood lactate lower as the subject progressed throughout the investigation. All serum plasma constituents were within clinically normal ranges and remained relatively stable. Despite a small loss of FFM, the subject was able to maintain muscular strength and aerobic fitness while concomitantly enhancing anaerobic capacity and power capabilities throughout the study period as he prepared for the 2000 Olympic freestyle wrestling trials.

Adult↗

PubMedDate not supplied

Influence of carbohydrate on immune function following 2 h cycling.

The influence of carbohydrate compared with placebo ingestion on changes in immune cell counts and functions following 2 h intensive cycling was studied in 12 trained cyclists who functioned as their own controls. The subjects performed two tests 2 weeks apart where they cycled for 2 h at approximately 64% Watts(max) while receiving 4 mL x kg(-1) x 15 min(-1) carbohydrate (6%) (Cho) or placebo (Pla) beverages. Blood samples were collected 30 min preexercise, and immediately and 1 h postexercise. The samples were assayed for plasma cortisol and epinephrine, blood leukocyte subset counts, PHA-induced lymphocyte proliferation, and natural killer cell activity (NKCA). Compared with Pla ingestion, Cho attenuated exercise-induced changes in plasma cortisol, blood neutrophil, and monocyte counts, but not in total blood lymphocyte, T cell, and NK cell counts, PHA-induced lymphocyte proliferation, and NKCA. Thus despite a strong attenuating influence of carbohydrate ingestion on exercise-induced changes in plasma cortisol and blood neutrophil and monocyte counts, other immune measures related to lymphocyte subset counts, and function were unaffected.

Adult↗

PubMedDate not supplied

Evaluation of leg-to-leg BIA in assessing body composition in high-school-aged males and females.

The current investigation was conducted to evaluate the accuracy of the Tanita 300WA leg-to-leg (LL) bioelectrical impedance analyzer (BIA) for measuring body composition in an American high-school-aged population. Body composition was determined in 77 students, comparing BIA measurements with the criterion, hydrostatic weighing (HW). Among the males, there were no significant differences found in percent body fat (%BF) between BIA (14.1 +/- 7.8%) and HW (14.9 +/- 9.1%); however, skinfolds (SK; 11.8 +/- 7.2%) were significantly different from HW. A significant correlation in fat-free mass (FFM) was found between BIA and HW (r = 0.96, p < 0.001), and the standard error of estimate (SEE) for FFM was 3.28 kg for males. In females, a significant difference (p < 0.001) in %BF was found for both BIA (26.4 +/- 5.7%) and SK (27.9 +/- 5.1%) when compared with HW (23.6 +/- 5.9%). The correlation in FFM between BIA and HW was lower (r = 0.78, p < 0.001) and the SEE for FFM was 2.93 kg for females. The Tanita 300WA LL-BIA system is appropriate for assessing body composition in male adolescents, but it warrants future research in female adolescents.

Adiposity↗