The purpose of this study was to compare the growth response elicited by an acute bout of resistance exercise (RE) conducted on a traditional weight stack device (WS) and a flywheel device (FW). Eight recreationally trained males (25 ± 9 y, 77 ± 27 kg) performed 4 sets of 7 repetitions of bilateral knee extension on each exercise device separated by 7 days. Muscle biopsies were obtained from the vastus lateralis at rest and 4 hrs post-exercise to examine the expression of selected myogenic and proteolytic genes. RE increased (P < 0.05) mRNA expression of Myogenin (3.6 vs. 3.6 fold), and MyoD (2.2 vs. 2.0 fold) and decreased (P < 0.05) expression of Myostatin (1.4 vs. 1.5 fold) to a similar degree on both exercise devices. There was no change in the expression of Atrogin-1, MuRF-1 or MRF4 following RE on either device. The only device mediated difference in the expression of the selected genes was observed in Atrogin-1 which was lower following RE on the FW versus the WS device. The current data shows that in the initial hrs following RE, use of the FW is as effective as the traditional resistance training devices (WS) in promoting the induction of genes involved with muscle remodeling and growth. / School of Physical Education, Sport, and Exercise Science

During periods of intense exercise the adenine nucleotide pool in skeletal muscle becomes partially depleted. Ribose has been shown to increase rates of both purine salvage and adenine nucleotide de novo synthesis in rat skeletal muscle. However, to date no research has been conducted on the effects of ribose on adenine nucleotide levels in human skeletal muscle. Therefore, the purpose of this investigation was to determine the effects of ribose supplementation on adenine nucleotide levels in human skeletal muscle during high-intensity exercise. To do this, an 11-day supplementation of either ribose (20 g.d-1) or placebo (glucose 20 g•d-1) was given to 16 healthy male subjects. After 72 hours of supplementation, the subjects performed five-days of high-intensity exercise designed to elicit significant reductions in adenine nucleotides. A 65 hour recovery period was completed following the exercise protocol. Muscle biopsies were performed at four different time points during the supplementation/exercise period.The exercise protocol elicited significant decreases in skeletal muscle adenine nucleotide levels of both the ribose and placebo groups (p<0.05). However, ribose supplementation was shown to partially attenuated the adenine nucleotide decrease. The placebo group demonstrated a 39% decrease, while the ribose group dropped 23% in TAN levels (p<0.05). The largest decreases were observed in ATP for both groups; however, the decreases were significantly greater in the placebo group (p<0.05). Both groups displayed a similar amount of replenishment in adenine nucleotides 65 hours following the 5-day exercise period. No differences were demonstrated in ADP or AMP for either the ribose and placebo groups throughout the investigation. Both groups displayed an increase in E MP post-exercise, but the increase was only significant in the ribose group (p<0.05). No differences in mean power, peak power, and fatigue were observed between the ribose and placebo group. However, the ribose group consistently displayed a non-significantly greater percent change (3.1 %) in mean power. / School of Physical Education

This study compared the exercise responses of a waxy starch (WS), resistant starch (RS), glucose (GL) and an artificially-sweetened placebo (PL) ingested prior to exercise. Ten college-age, male competitive cyclists completed four experimental protocols consisting of a 30 min isokinetic, self-paced performance ride preceded by 90 min of constant load cycling at 66% VO2max. Thirty min prior to exercise, they ingested 1 g•kg-1 body weight of GL, WS, RS, or PL. A familiarization trial was first conducted to eliminate a potential order effect. An order effect was evidenced by lower (p<0.05) work rates during the performance ride of the first trial (390 ± 26.1 kJ) than the other four trials. No order effect was observed for the remainder of the experimental treatments which were performed in a single-blind, randomized fashion. At rest, GL elicited greater (P<0.05) serum glucose and insulin responses than all other trials. During exercise, however, serum glucose and insulin responses were similar among trials. Blood C-peptide and glucagon responses were also similar among trials. The mean total carbohydrate oxidation rates (CHOox) were higher (p<0.05) during the GL, WS, and RS trials (2.59 ± 0.13, 2.49 ± 0.10, and 2.71 ± 0.15 g•min-1, respectively) compared to PL (2.35 ± 0.12 g•min-1). Subjects were able to complete more work (p<0.05) during the performance ride when they ingested GL (434 ± 25.2 kJ) or WS (428 ± 22.5 kJ) compared to PL (403 ± 35.1 kJ). They also tended to produce more work with RS ingestion (418 ± 31.4 kJ), although this did not reach statistical significance (p<0.09). These results indicate that pre-exercise CHO ingestion in the form of starch or glucose maintained higher rates of total carbohydrate oxidation during exercise and provided an ergogenic benefit during self-paced cycling. / Human Performance Laboratory

In an attempt to investigate the role of the endogenous opioid peptides in substrate utilization and hormonal responses to exercise, eight trained cyclists completed two exercise trials at each of two distinct intensity/duration combinations. Briefly, cyclists completed two trials at 70% VO2max for 90 minutes and two trials at 90% VO2max until exhaustion. Trials were conducted following the administration of the opiate antagonist naloxone (NAL) (0.1 mg-kg-1 bolus + 0.1 mg-kg-1-·hr-1) or volume matched saline (SAL). Serum glucose was maintained at significantly higher levels at 60 and 90 minutes of exercise in 70% NAL vs 70% SAL. Serum glucose was significantly higher at all points during exercise and at 30 and 60 minutes of recovery in 90% NAL vs 90% SAL. Serum insulin was not altered by naloxone administration at either 70% or 90% trials. Serum Cpeptide was significantly higher at 60 and 90 minutes in 70%-NAL vs 70% SAL, and was significantly lower during exercise in 90%-NAL vs 90% SAL. Plasma glucagon was not different during exercise in the 70% trials, but was significantly higher during exercise in 90%-NAL vs 90%-SAL. The glucagon:insulin molar ration was not significantly altered by naloxone administration in any trial. Rating of peceived exertion was significantly higher during exercise in 70%-NAL, but was not different during exercise in the 90% trials. However, time to exhaustion was significantly (18%) reduced in 90%-NAL vs 90%-SAL. No systematic differences were observed in the cardiorespiratory responses to exercise at either intensity, although pulmonary ventilation was modestly (7%) elevated in 90%-NAL. Thus, opiate antagonism prevents the decline in serum glucose seen in prolonged exercise without altering substrate oxidation, and with minimal influence on the pancreatic hormone response. In contrast, opiate antagonism potentiates the hyperglycemic response to high intensity exercise at least in part by altering pancreatic hormone responses which may contribute to the hyperglycemia. / School of Physical Education

The effect of heat acclimatization on aerobic exercise tolerance in the heat, and on subsequent anaerobic exercise performance was investigated. Ten male subjects were acclimatized by exercising 90 minutes per day for eight days in the heat (39.7 C db, 31.0% RH) on a bicycle ergometer at a workload corresponding to 54% of V02 max. Prior to, and following heat acclimatization, the subjects performed six hours of intermittent, submaximal (50% V02 max) exercise in the heat (HET). A 45 sec maximal bicycle ride was performed before (sprint 1) and after (sprint 2) each HET. Mean ( ± SE) resting plasma volume was higher (+9.2 + 1.7%) in acclimatized subjects (ACC) compared with unacclimatized (UN) subjects (P<0.001). Acclimatization resulted in reductions in the mean exercise heart rate (160 + 3 vs. 144 ± 3, P<0.001) and mean rectal temperature (38.13 + 0.08 vs 37.91 + 0.05, P<0.01). Muscle glycogen utilization during the HET was greater in the UN trial (57.4 + 5.1 mmol/kg) than the ACC trial (28.6 + 6.4 mmol/kg, P<0.05). No differences were noted between the UN and ACC trials with respect to blood glucose, lactate (LA), or respiratory exchange ratio during the HET. Total work output during sprint 2 was reduced compared with sprint 1 in the UN trial (24.01 ± 0.80 vs. 21.56 + 1.18 kJ, P<0.05). Post exercise muscle pH was significantly (P<0.05) higher following sprint 2 (6.86) than sprint 1 (6.67) in the UN trial. Associated with this reduction in anaerobic exercise performance, an attenuated accumulation of LA and fall in pH was noted in the blood. No differences between sprints 1 and 2 were observed for the ACC trial in total work, musce pH, or blood LA. As a result of sprint exercise in both UN and ACC trials, a decrease in muscle potassium (K+) was noted (P<0.05), which was accompanied by a 0.8 to 2.2 mmol/l increase in antecubital venous blood K+. Following sprint exercise, serum K+ was below pre sprint values for up to 15 minutes, suggesting a rapid and accelerated uptake of K+.These data indicate that eight days of heat acclimatization produced a shift in fuel selection during submaximal exercise in the heat through an enhanced delivery of blood borne substrate. The observed muscle glycogen sparing during submaximal exercise may be associated with the enhanced ability to maintain high levels of anaerobic energy release and performance of highly intense exercise following prolonged exertion in the heat.

The purpose was to describe the physiological response and nutritional consumption of one athlete competing in the RAAM. The 1999 RAAM covered 4727 kilometers from Irvine, CA. to Savannah, GA. The subject was a 36 year-old male elite triathlete with 12 years of training experience. VO2max was 4.32 L/min. Prior to RAAM, cycling economy was measured at 100 and 150 watts. During RAAM, the following measurements were continuously recorded: heart rate, power output, nutritional intake, and body mass. Power output was recorded using a hub dynamometer (4 strain gauges, PowerTap). The subject completed RAAM in 10.1 days and spent 18.6 h/day cycling. Mean cycling values for power output, mechanical energy and heart rate were: 97 watts, 6676 kjoules and 99 b/min. Daily cycling energy expenditure was 7,946 +/- 1435 kcal/day. Energy intake averaged 6,812 +/- 914 kcal/day with 67% CHO, 24% fat, and 9% protein. Body mass decreased by 2.5 kg and percent fat decreased from 9.2% to 7.1%.

Glucose is a principle precursor for milk lactose and de novo synthesis of milk fat; therefore exercising during lactation could create competition for glucose between exercising muscle and lactating mammary gland. This study investigated the combined effects of maternal dietary glucose (20%, 40%, 60%), exercise (chronically exercised, sedentary) and litter size (8, 12 pups) on rat mammary gland composition, milk composition, milk yield and pup growth. Chronic exercise increased milk fat concentrations and an interaction between chronic exercise and 20% dietary glucose decreased milk lactose concentrations compared to 40% or 60% glucose diets. Restricting maternal dietary glucose also decreased milk fat concentrations and exercise decreased mammary fat. In addition, pups of dams fed the 40% glucose diet were heavier on lactation day 15 than pups of dams fed the 60% diet. These results suggest that competition for glucose occurs and that a 40% glucose maternal diet may be more appropriate for pup growth.

Graduation date: 1999

Typescript. / Thesis (Ph.D.)--University of Hawaii, 1986. / Bibliography: leaves 164-175. / Microfilm. / ix, 175 leaves, bound ill. 29 cm

Thesis (M.S.)--University of Hawaii at Manoa, 2005. / Includes bibliographical references (leaves 34-36). / viii, 36 leaves, bound col. ill. 29 cm