This study was conducted to determine if improvements in glucose tolerance could be demonstrated following an acute bout of progressive resistance exercises. Fourteen individuals, not currently weight training, were assigned to two groups using the guidelines established by the WHO for NIDDM and normal (CON), based on the results of a three hour 75 g (-1.2M) load oral glucose tolerance test (OGTT). Eight blood samples were collected during the OGTT and assayed for glucose, insulin, and C-peptide. Each subject from the NIDDM (n=7) and CON (n=7) groups participated in a familiarization period, including a IRM, with eight different Nautilus selectorized exercise machines utilizing both the upper and lower body. A 3 set x 10 repetition exercise protocol based on the IRM was conducted and followed 18 hours later by another OGTT. Two day diets were replicated from the prior OGTT. Analysis of variance failed to demonstrate significant differences in the total responses or at any specific sampling points from pre to postprotocol for glucose (p=0.53), C-peptide (p=0.07) or the C-peptide:insulin ratio (p=0.16) in either group. Blood insulin levels from pre to postprotocol were significantly reduced (p=0.001) by 24% and 22% for the NIDDM and CON groups, respectively. These data suggest that a single series of progressive resistance exercises improve insulin uptake by the tissues without augmenting glucose disposal. / School of Physical Education

The purpose of this study was to examine the effects of warm-up intensity on anaerobic performance and recovery in children. Six male children (11.0 ± 0.6 yr) performed an IAT following a mild (85% of VAT), intense (115% of VAT), or no warm-up protocol. VAT was determined during a previously performed GXT. A catheter allowed for multiple blood samples drawn thoughout each trial. Performance indices, PP, MP, TW, and FI%, were not significantly different across trials. Blood analysis revealed significant interactions for recovery [LA] and [HC03-], although no significant interaction for pH values. There was also a significant interaction for V02 recovery pattern. The ALA (5.2 vs. 7.1 mmol•1-1, respectively) and AHC03- (6.1 vs. 8.4 mmol-l-1, respectively) were significantly lower for the AVAT trial compared to NWU trial. These data indicate that the AVAT warm-up resulted in less acid-base balance disturbance suggesting greater dependence on aerobic metabolism during the IAT. / School of Physical Education

Previous studies have suggested that if exercise intensity is established by perceived effort, the metabolic demand varies among exercise machines and the treadmill optimizes energy expenditure (EE). However, these studies have been completed utilizing young people with normal body fat percentages. Therefore, the purpose of this study was to assess whether there was a difference in acute energy expenditure when obese people used different exercise modes at a self-selected intensity (RPE 11-12) commonly recommended for overweight individuals. Twelve obese subjects (7 male; 5 female; BMI >29 kg/m2), aged 37-71 years completed two familiarization trials on four machines: treadmill (TM), stationary cycle (C), Body Trec elliptical arm/leg (BT), and Airdyne (AD). On separate days, subjects then completed a 15 minute trial on each machine at a self-selected intensity corresponding to a target RPE of I 1-12 on the Borg 15 point scale. Machine order was randomly assigned, and subjects were blinded to the workload throughout each trial. Workload was self-adjusted during the first 5 minutes and then remained stable for the rest of the trial. Physiological data were obtained during the last five minutes of each trial via HR telemetry and the Aerosport TEEM 100. The group means were compared across modes using a one-way repeated measures ANOVA. Significant differences (p <0.05) were observed across exercise modes for energy expenditure. The BT produced the highest rate of energy expenditure among exercise machines and C the lowest (8.0±2.0, 6.6±2.1, 6.3±2.0, 5.3±2.1 Kcal/min, for BT, TM, AD, and C, respectively). These results suggest that perceptually-based exercise prescriptions are not reliable across modes typically found in a fitness center environment, and that weight-bearing arm/leg exercise optimizes EE during self-selected exercise of moderate intensity in obese subjects. / School of Physical Education

Exercise prescription intensity is traditionally defined using a target heart rate (HR) as a surrogate measure of oxygen uptake (V02). The ACSM Guidelines recommends the use of a percentage of the maximal HRR because it is thought to match a similar percentage of maximal V02 (%V02max). However, several recent studies have challenged the notion that a given percentage of MHRR matches with the same percentage of V02max in older subjects. The purpose of this study was to assess the difference between percentages of MHRR and V02ma, and evaluate the influence of age on the agreement between these two variables across a range of exercise intensities. The sample included 530 subjects (232 men and 298 women, mean ages of 46.6 + 11.7 years and 43.3 + 11.3 years respectively) who completed a maximal treadmill test to volitional fatigue using the BSU/Bruce Ramp protocol. Heart rate and V02 data from minutes 3, 6, and 9 were converted into percentages of MHRR and V02mai,. Subjects were excluded from the analysis if they failed to achieve an RER,„a,,>1.0. Minutes 3, 6, and 9 represented 45.2 ± 11, 66.0 ± 15, and 83.1 ± 12% of VO2.x, respectively. A one-way ANOVA showed that statistically significant differences existed between the treatment means of relative intensity at minutes 3, 6, and 9 at a p-value of <0.05. The influence of age was assessed by correlation with the difference between percentages of MHRR and VO2max at minutes 3, 6, and 9. In addition, younger (<60 years of age) and older (>60 years of age) subjects were compared using an unpaired t-test. The association between age and the difference between percentages of HRR and VO2max were -0.24, -0.22, and - 0.26 at minutes 3, 6, and 9, respectively. The difference in the relative intensities of HRR and VO2max was greater for older subjects at minutes 3 and 6 (-7.0 vs. -2.2, -3.2 vs. -0.8%) but was smaller at minute 9 (-0.1 vs. -3.2%). A Scheffe post-hoc analysis was used to compare the differences between the treatment means of relative intensity. In conclusion, these results confirm the notion that percentages of MHRR. tend to underestimate percentages of VO2max in older subjects, however the differences observed within the present study were smaller than those reported previously. The small but statistically differences between the techniques would not appear to invalidate the use of percentages of MHRR as surrogate markers of percentages of VO2max in these subjects. / School of Physical Education

The influence of caffeine on the metabolic and catecholamine responses to mild exercise in a cold and a warm environment was studied in eight healthy males. The subjects performed 60 minutes of cycling at 50% VO2max in a cold environment (5°C and 70% relative humidity) and a warm environment (28°C and 50% relative humidity) 30 minutes after ingesting caffeine (5mg/kg body weight) or placebo (dextrose). Caffeine ingestion prior to exercise in the warm environment resulted in increased plasma epinephrine, with no effect on plasma norepinephrine. Neither lipid nor carbohydrate metabolism was altered by caffeine in the warm trial. Exercise in the cold environment (placebo) produced increased oxygen consumption and carbohydrate metabolism, decreased lipid metabolism, and no difference in plasma catecholamines compared with the warm-placebo trial. Responses to the combination of caffeine ingestion and the cold environment did not differ from cold-placebo responses in oxygen consumption or respiratory exchange ratio during the cycling bout. However, in the cold-caffeine trial plasma epinephrine was elevated. In addition, fat oxidation, serum free fatty acids, and serum glycerol were elevated in the cold-caffeine condition. Carbohydrate oxidation was depressed, while serum glucose and blood lactate were elevated in this trial. The results of this study indicate that caffeine increases plasma epinephrine; cold increases oxygen consumption and carbohydrate metabolism, while decreasing lipid metabolism; and the combination of caffeine and cold during exercise increases plasma epinephrine and lipid metabolism, but decreases carbohydrate metabolism. / Human Performance Laboratory

There is no abstract available for this dissertation. / Human Performance Laboratory

As a part of a project designed to mimic a Space Shuttle flight (LMS), eight healthy males completed 17 d of -6° head down tilt bedrest to assess the in vivo torque velocity relationship of the calf muscle group and the cardiorespiratory responses to supine cycling exercise. The subjects age, height, and weight were 42.7 ±8.1 y, 182.3 ±6.5 cm, and 82.2 ±12.1 kg, respectively. Testing was completed prior to bedrest (CON), on bedrest days 2 & 3 (BR 1), 8 & 9 (BR2), and 13 & 14 (BR3), as well as recovery days 3 & 4 (R1), and 7 & 8 (R2). Maximal plantar flexion force production at seven angular velocities (0, 30, 60, 120, 180, 240, 300'- s-1) was unchanged (P>0.05) during bedrest and recovery. Muscle biopsy specimens obtained from the soleus before and on day 17 of bedrest showed no change (P>0.05) in muscle fiber composition, muscle fiber area, capillary to fiber ratio, or capillary density. Citrate synthase activity decreased 21% (P<0.05) from 122.1 ±7.8 to '97.1 ±5.1 µmol -min-1 • g dry wt-1, while phosphorylase activity was unchanged (P>0.05). VO2max (L • min-1) was decreased (P<0.05) from CON (3.24 ±0.20) during BR1 (2.99 ±0.17; -7.3%), BR2 (3.00 ±0.17; -7.1%), BR3 (2.92 ±0.20; -9.0%), and R1 (3.02 ±0.20; -6.6%), but was not different (P>0.05) than CON by R2 (3.13 ±0.19; -3.3%). Maximal heart rate and ventilation did not change (P>0.05) from CON during bedrest or recovery. Initial changes in VO2max (BR1) were significantly correlated with fluid balance during bedrest day 1 (r=0.91, P<0.05). These data suggest that the testing protocols in this investigation may be sufficient to attenuate functionally significant changes in muscle morphology and strength during 17 d of simulated microgravity. The results also suggest that the time course for changes in VO2max are not linear and are related to the initial changes in body fluid volumes. / Human Performance Laboratory

Two experiments were done to study the effects of L-carnitine supplementation (CNsup) during exercise. EXP 1, examined the effect of CNsup on lipid oxidation and muscle glycogen utilization during submaximal EX. Triglycerides were elevated by a fat feeding (90g fat), 3 h later subjects cycled for 60 min at 70% VO2max (CON). Muscle biopsies were obtained preEX, after 30 and 60 min of EX. Blood samples were taken preEX and every 15 min of EX. Subjects randomly completed two additional trials following 7 and 14 days of CNsup (6 g/day). During one of the trials, subjects received 2000 units of heparin 15 min prior to EX to elevate FFA (CNhep). There were no differences in V02, RER, HR, g of CHO and fat oxidized among the three trials. Serum total acid soluble (TASC) and free carnitine (FC) increased with CNsup (CON, 71.3 ± 2.9; CN, 92.8 ± 5.4; CNhep, 109.8 ± 3.5 mol·g'). Muscle carnitine concentration at rest was unaffected by CNsup. During EX, TASC did not change, FC decreased (p<0.05) and SCAC increased (p<0.05). With CNsup the decrease in FC was less (~50%) (p<0.05) and the increase in SCAC was greater (~200-300%) (p<0.05) compared to CON (free 65%; SCAC 150%). Pre and postEX muscle glycogens were not different. EXP 2, examined the effects of CNsup on blood lactate accumulation during maximal EX. Subjects cycled for 4 min at ~100% VO2max (CON). Exercise was repeated following 6 and 13 days of CNsup (6 g/day). Serum TASC and FC were elevated due to CNsup. Blood Lactate was measured prior to and 0, 3, 5, and 7 min postEX. CNsup resulted in less (p<0.05) lactate accumulation compared to CON. There were no differences between DAY-6 and DAY-13. / Human Performance Laboratory

There is no abstract available for this dissertation. / School of Physical Education, Sport, and Exercise Science

This study was designed to determine if highly caffeine sensitive (HS) and less caffeine sensitive (LS) individuals differ in metabolic substrate use and endurance performance following caffeine ingestion. Twenty subjects were placed into HS and LS groups based on a series of 6 isokinetic cycle ergometer rides in which perceived exertion was held constant and work output was measured. Subjects who performed significantly more work following caffeine ingestion were classified as HS while those who did not were classified as LS. Seven subjects were selected from each of these groups to perform the experimental trials. These trials were conducted 60 min after ingestion of 6 mg-kg-1 caffeine or a placebo and consisted of a 30 min ride at70% VO2max followed by a 60 min isokinetic performance ride. The HS group achieved a higher accumulated workload over the last 30 min of the ride following caffeine ingestion compared to the placebo condition. No increase in work output was observed in the LS group following caffeine ingestion. There were no significant differences between treatments in either the HS or LS group in amount of muscle glycogen utilized during the first 30 min of the ride. During the caffeine trials serum glucose was elevated at 20, 30, and 50 min, free fatty acid concentration was elevated at the zero time point, and glycerol concentration was elevated at 60 and 90 min compared to the placebo trials. However, there were no differences between the HS and LS groups in these parameters. These data suggest that the ergogenic effects of caffeine in some individuals are not due to an alteration in substrate utilization, but may be related to an alteration in neural perception of effort. / School of Physical Education