Two investigations were conducted to examine the influence of beta-adrenergic blockade on cardiovascular, respiratory, metabolic, and thermoregulatory responses to maximal and submaximal exercise in both highly trained and untrained subjects. In both studies, subjects received randomized and double-blind oral medication with atenolol (100 mg/day), propranolol (160 mg/day), and placebo. In the first study significant reductions in HR max and ‘VO₂ max resulted during the atenolol and propranolol treatments in both the trained and untrained subjects. However, the reductions in ‘VO₂ max were significantly greater in the trained subjects and both groups experienced their greatest reduction during the propranolol treatment. In all subjects, the magnitude of reduction in HR max was significantly greater than the concomitant decrease in ‘VO₂ max. It is concluded that untrained subjects have a greater compensatory reserve than do trained subjects during maximal exercise while under beta-adrenergic blockade. In addition, significant advantages were found with the use of a selective compared to a non-selective beta blocker. Thermoregulation during prolonged exercise in the heat with beta blockade was studied in fourteen subjects. Subjects performed 90-minute cycle ergometer rides at a workload equivalent to 40% of the subjects' unblocked ‘VO₂ max. Rectal temperature was slightly higher during the atenolol trial compared to the placebo but was not different during the propranolol trial compared to the placebo. Skin blood flow was significantly lower during the propranolol trial compared to both the atenolol and placebo trials, but it did not differ significantly between the atenolol and placebo trials. Maintenance of rectal temperatures appeared to be achieved through changes in sweat rate, skin blood flow, and a reduced heat production, i.e., lower ‘VO₂ during the propranolol trial. The decrease in cutaneous blood flow reported during the propranolol trial is likely associated with the associated increase in TPR. This increase in TPR would help to compensate for the lower ‘Q and, hence, help maintain mean arterial pressure. Changes in substrate utilization, i.e., decreased lipolysis, during the beta-blocked trials may also be indicated. Lastly, the inability of two subjects to complete the 90-minute ride, the elevated RPE values, and the additional side effects reported during the propranolol trial would indicate an advantage for the use of a selective blocker.

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Increased bone density has been observed following physical training. However, it is not known whether the mechanical forces of muscular contraction, gravitational pull, or a combination of these forces are required to cause this adaptation. Therefore, the purpose of this study was to determine which mechanical force, muscular contraction or gravitational pull, offered the greatest contribution to increased bone mineral content observed following either swim or run training. METHODS: Female Wistar rats were randomly assigned to one of three groups: 1) Sedentary Control (SC; n = 12), 2) Run Trained (RT; 27.7 m/m, 8% incline, 2 hrs/day; n = 20), and 3) Swim Trained (ST; 2 hrs/day, 2Y/ body weight; n = 14). The animals were sacrificed after 9 weeks of training and the humeri and femurs were removed for analysis.RESULTS: Femur weight, length, diameter, and ponderal index (a measure of robustness), and bone mineral content (BMC) were not different between the three treatment groups. However, femur cortical thickness was significantly (p < 0.01) smaller in the RT when compared to ST and SC rats. The ST humeri were significantly (p < 0.05) heavier, wider, and had a greater BMC when compared with those of the RT and SC rats, while cross sectional area was unaffected by physical training. CONCLUSION: The results of this study indicate that the mechanical forces applied by the swim training protocol produced marked bone adaptation in the ST animals following 9 weeks of physical training. Whereas, the combined mechanical and gravitational forces applied during running by the RT rats produced minimal adaptation of bone following 9 weeks of physical training.

Exercise performance was examined after ingestion of 45 g of liquid carbohydrate (LCHO), solid carbohydrate (SCHO), or water (W) 5 min before 1 h of intense exercise.An (CHO) meal (200 g) taken 4 h prior to exercise was combined with a solid CHO feeding (M+SCHO). Ten well-trained male cyclists (4.35 + 0.11 1/min V02 max) performed 45 min of cycling at a work load requiring an average oxygen uptake of 77.1% V02 max followed by a 15 min performance ride. Serum glucose values were elevated by 18% and 24% during SCHO and LCHO, respectively, as compared to W. Blood glycerol concentrations were significantly (p<0.05) lower during M+SCHO and significantly higher during W at 40, 50 and 60 min of exercise as compared to all other trials. Muscle biopsies at 0 and 45 min revealed no significant differences in muscle glycogen concentration or total use between the 4 trials. Total work produced during the final 15 min of exercise was significantly greater during M+SCHO (194735 + 9448 NM) as compared to all other trials and significantly greater during LCHO and SCHO (175204 + 11780 and 176013 + 10465 NM, respectively) as compared to W (159143 + 11407 NM). Carbohydrate oxidation was highly correlated (r=0.94) with work production. These results suggest that exercise performance is enhanced with the ingestion of 45 g of CHO 5 min prior to one hour of intense cycling. Further improvements in performance were found when exercise was preceded by a CHO meal 4 h prior to exercise in combination with a solid CHO feeding given immediately before exercise.

The purpose of this investigation was to determine the effect of solute carbonation and carbohydrate (CHO) concentration on gastric emptying during prolonged cycling. Eight highly trained male cyclists completed four two hour cycling bouts during which one of four test solutions were consumed. The test solutions consisted of a carbonated 10 % CHO solution (CK), a non-carbonated 10 % CHO solution (NCK), a carbonated non-CHO solution (CNK), and a noncarbonated non-CHO solution (NCNK). Approximately 150 ml (8.5 ml/kg/hr) of one of the test solutions were consumed every fifteen minutes. The first 105 minutes of each trial was a continuous ride on an electrically braked cycle ergometer at 70 % V02 max. The last fifteen minutes of each trial was a self paced "performance ride" on an isokinetic cycle ergometer. The subjects were instructed to complete as much work (kilojuoles) as possible during the performance ride. Gastric contents were aspirated within five minutes following the performance ride and analyzed to determine the amount of the original test solution emptied.Of the original1273 ml ingested during each trial, the volumes emptied were 993.6 ±78.1, 1064.6 ±75.3, 1097.4 ±94.2, and 1147.2 ±95.9 ml (±SE) for CK, NCK, CNK, NCNK, respectively. The only significant difference was between trials CK and NCNK (P < 0.05). There were no statistically significant differences in total work output between any of the trials. However, when the performance data from the CHO trials were pooled and compared to the combined data from the non-CHO trials, total work output was significantly greater (P < 0.05) in the CHO group (1185.19 + 21.81, and 1092.85 + 21.52 Kj (+ SE) for the CHO and non-CHO groups, respectively). These data suggest that carbonated or 10 % CHO solutions, independent of one another, may not significantly inhibit gastric emptying. They also suggest that there may be some interaction between carbonation and CHO concentration which caused an additional inhibition of emptying. In addition, the potential for improved performance exists with the consumption of 10 % CHO solutions. / Human Performance Laboratory

The purpose of this study was to determine the association of age, gender, and cardiorespiratory fitness level upon normative heart rate and systolic blood pressure (SBP) responses per MET during the BSU/Bruce Ramp protocol. This research was delimited to 451 subjects, 201 men (mean age 46.5 ± 11.9 yrs) and 250 women (mean age 42.9 ± 11.4 yrs), low to moderate risk subjects. The majority of subjects were tested to enter the Ball State University Adult Physical Fitness Program. These subjects were tested using the BSU/Bruce Ramp protocol between 1992 and 1998.Multiple regression showed gender had a positive association upon submaximal SBP values. Gender's association with heart rate was negative between minute 3-6 and positive between minute 6-9. Age only had an association upon submaximal heart rate, which was negative. Cardiorespiratory fitness had a negative association upon SBP between minute 6-9 and a negative association with heart rate between minute 3-6.SBP increased 6.6 ± 4.4 and 6.0 ± 4.2 mmHg/MET between minute 3-6 for men and women, respectively. Analysis of variance demonstrated gender was not statistically significant between minute 3-6. SBP increased 4.7 ± 3.1 and 3.8 + 2.7 mmHg/MET between minute 6-9 for men and women, respectively. Gender was statisticallysignificant between minute 6-9 (p<.05). Heart rate increased 8.5 + 2.3 and 10.7 + 3.3 bpm/MET between minute 3-6 for men and women, respectively. Analysis of variance demonstrated gender was statistically significant between minute 3-6 (p<.05). The increase was 9.5 + 2.3 and 9.2 + 2.7 bpm/MET between minute 6-9 for men and women, respectively. Gender was not statistically significant between minute 6-9.In conclusion, this study demonstrated that the normative hemodynamic responses during the BSU/Bruce Ramp protocol are similar to submaximal normative data previously reported in the literature for incremental type protocols. / School of Physical Education

Call number: LD2668 .T4 1986 W544 / Master of Science / Human Nutrition

Resistance training is widely prescribed for rehabilitation of injuries and as a method to improve athletic performance. It is accepted that resistance training increases the maximal force production of whole muscle and it has been suggested that the velocity of shortening can increase as well. However, little is known about the effects of resistance training at the cellular level. Therefore, we investigated morphology, force production, velocity, and force-velocity-power relationships of single chemically skinned muscle fibers from chronically resistance trained humans, including cross sectional area (CSA), peak Ca²⁺ -activated force production (P₀), specific tension (P₀/CSA), unloaded shortening velocity (V₀), and isotonic contractions. The untrained group (NT) group consisted of sedentary males (n=6, age =27 ± 2 yrs) while the chronically trained group (CHRT) group consisted of males with 7.7 ± 0.4 yrs resistance training experience (n=6, 22 ± 1 yrs). Maximum voluntary isometric and isokinetic knee extensor strength were measured along with 6 repetition maximum (6RM) free weight bench press and leg press. Muscle biopsies were obtained from the vastus lateralis. Chemically skinned single muscle fibers were mounted between a force transducer and servo-controlled motor and subjected to slack tests to determine peak Ca²⁺ -activated force (P₀) and unloaded shortening velocity (V₀). Isotonic load clamps were used to determine the force-velocity-power relationship. All fiber experiments were performed at 15°C. Fiber myosin heavy chain (MHC) content was determined by gel electrophoresis. The CHRT group was 119% and 81% stronger for 6RM leg press and bench press respectively. Peak isometric torque was 28% greater for the CHRT subjects and was significantly higher at all isokinetic speeds tested. No differences were seen in strength or isokinetic power between groups after normalization for lean body mass. CHRT fibers (n=213) expressing type I, IIa, and I₀a/IIx MHC were significantly greater in CSA (+41%, +51%, and +33%, respectively) and produced significantly greater P₀ (+37%, +48%, and +34%, respectively) than NT fibers (n=236). However, P₀/CSA was not different between CHRT and NT groups. Fibers expressing type IIa/IIx fibers produced greater P₀/CSA than IIa which produced greater P₀/CSA than type I. The P₀/CSA relationship between fibers within groups was type IIa/IIx>IIa>I and was significant for both groups. Fiber V₀ was not different between groups. Absolute power was significantly greater in the CHRT for all fiber types whereas power normalized for fiber volume was not different between groups. This resulted in a significantly greater force at peak power for all but type IIa/IIx fibers and trends for greater velocity at peak power. Single-cell contractile function in terms of V₀ and P₀/CSA, measured under standardized conditions, appears to be unaltered as a result of long term CHRT in young adult males. Group differences in absolute P₀ can be attributed solely to the greater CSA of the CHRT fibers. Long-term CHRT is not associated with a difference in fiber V₀. Therefore, the greater power was due entirely to the greater force. These data suggest that differences in whole muscle strength and power between NT and CHRT groups are primarily due to differences in fiber CSA rather than differences in cross-bridge mechanisms of contraction. Supported by National Institute of Health grant R3AR46392A. / Graduation date: 2002

Seven men were studied during 30 minutes of leg ergometer cycling at approximately 70% V02 max to determine the effects of caffeine ingestion on the utilization of muscle glycogen. A caffeine solution (250 ml; 5 mg/kg body weight) given one hour prior to exercise (CAF trial), decreased the rate of muscle glycogen depletion by 36 + 11.86% (p. .005) as compared to a decaffeinated control trial. During the CAF treatment, there was a 16% increase in serum FFA prior to exercise. Exercise resulted in a removal of FFA from the blood in both trials. Muscle triglyceride levels prior to exercise in the CAF trial were nearly 23% higher than control levels and suggest, that excess FFA present prior to exercise in the CAF trial were esterified into triglyceride. Subsequent post-exercise values indicated a greater utilization of endogenous lipid. A model based on caffeine's stimulatory effects on muscle lipid mobilization and its inhibitory action on muscle phosphorylase a appears to be responsible for the lessened use of muscle glycogen.