Abstract PO2 DEPENDENCE OF OXYGEN CONSUMPTION IN SKELETAL MUSCLE OF DIABETIC AND NON-DIABETIC RATS By: Alexander C. Liles A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at the Medical College of Virginia Campus, Virginia Commonwealth University Virginia Commonwealth University, 2017 Advisor: Roland N. Pittman, Ph.D. Department of Physiology and Biophysics Type 2 diabetes mellitus (T2DM) is a major medical problem around the world, affecting nearly 6% of the world’s population. This study was an attempt to better understand physiological changes the disease may cause to the microcirculation and more specifically, to assess the dependence of oxygen consumption in skeletal muscle of a diabetic animal model. The spinotrapezius muscles of Goto-Kakizaki (G-K) and Wistar control rats were used to measure interstitial using phosphorescence quenching microscopy. The G-K rats spontaneously develop T2DM and serve as an appropriate model for the disease in humans. By rapidly arresting blood flow in the tissue and observing the resulting changes, an oxygen disappearance curve (ODC) was created. The ODC was used to calculate oxygen consumption rate (VO2) over the physiological range of PO2 values. The resulting VO2 vs PO2 curves were analyzed using Hill’s equation to fit the data and obtain values of several key parameters to quantitatively describe the PO2 dependence of oxygen consumption. When compared to healthy control rats, the G-K rats exhibited a significantly higher Vmax, or maximum rate of oxygen consumption, compared to the Wistar rats. The two rat sub-strains had similar values for P50, which indicates the PO2 at half maximal consumption. The overall higher maximal rate of consumption by the diseased animals could be explained by some disconnect in the consumption of oxygen by the mitochondria and the normal corresponding production of ATP. In conclusion, it was demonstrated that in situ muscle tissue from both diabetic and non-diabetic rats had a PO2 dependence of oxygen consumption over a wide range of PO2 values and the muscles of diabetic animals consumed oxygen at a higher maximal rate.

Adult chickens employ endothermy – internal generation of heat that maintains a constant body temperature (Tb). Prior to hatching, chicken embryos are ectothermic - controlling Tb by external heat sources. Upon hatching, the hatchling transitions from an ectotherm to an endotherm that has been shown to be delayed by hypoxia. In this study, whole animal oxygen consumption () and liver, heart, and skeletal muscle citrate synthase activity (CSA) and were measured during this transition to endothermy in chickens incubated in normoxia and hypoxia (15% O2). The only significant differences in occurred in 48 hour old hatchlings where was lower in normoxic hatchlings. There were no differences in CS activity between age and incubation oxygen levels. Additionally, preliminary 2-D protein gels of embryo and hatchling liver show changes in the proteome upon hatching. Results suggest that hypoxia had no significant effect on CSA and a minimal effect on .

The purpose of this study was to compare physiological variables (i.e. oxygen consumption, blood lactate, heart rate, respiratory exchange ratio) during exercise on a double poling ergometer modified for sit skiers to a field test for the same skiers. Three male and four female athletes from the Canadian National / Developmental team (17-54 years of age, ranging in ability from a complete T7 spinal injury to cerebral palsy) completed a field test and a double poling ergometer protocol separated by at least 24 hours. Both protocols consisted of three maximal sets of skiing of three minutes duration per set separated by approximately one and a half minutes rest. A wireless metabolic system (Sensormedics, VmaxST or Cosmed, K4b2) and heart rate monitor were used to measure physiological responses during each test. Arterialized blood lactate was measured before and after each set and for 15 minutes post exercise. There were no significant differences between the field and ergometer tests for peak oxygen consumption (VO2 peak) (field=35±6 mL/kg/min vs. ergometer=33±7 mL/kg/min; p=0.491). However, significantly higher peak heart rate (field=173±5 bpm vs. ergometer=178±4 bpm; p=0.046) and respiratory exchange ratio (RER) (field=1.2±0.1 vs. ergometer=1.4±0.1; p=0.022) were found during the double poling ergometer protocol. There were no significant differences in blood lactate at baseline and after set one between protocols. However, a significantly higher lactate was found after set two (field=7±4 mmol/L vs. ergometer=12±5 mmol/L; p<0.001) and set three (field=8±3 mmol/L vs. ergometer=13±4 mmol/L; p=0.001) during the ergometer protocol compared to the field test. There were moderate correlations between the field and double poling ergometer for VO2 peak (r=0.79; p=0.035), and peak blood lactate (r=0.83; p=0.02). However, no correlations were found between protocols for peak heart rate (r=0.37; p=0.491) and RER (r=0.54; p=0.207). Results of this study suggest that the double poling ergometer is similar to a field test for evaluating VO2 peak in elite cross country sit skiing athletes; however, the ergometer test involves a higher heart rate and anaerobic component.

The purpose of this study was to compare physiological variables (i.e. oxygen consumption, blood lactate, heart rate, respiratory exchange ratio) during exercise on a double poling ergometer modified for sit skiers to a field test for the same skiers. Three male and four female athletes from the Canadian National / Developmental team (17-54 years of age, ranging in ability from a complete T7 spinal injury to cerebral palsy) completed a field test and a double poling ergometer protocol separated by at least 24 hours. Both protocols consisted of three maximal sets of skiing of three minutes duration per set separated by approximately one and a half minutes rest. A wireless metabolic system (Sensormedics, VmaxST or Cosmed, K4b2) and heart rate monitor were used to measure physiological responses during each test. Arterialized blood lactate was measured before and after each set and for 15 minutes post exercise. There were no significant differences between the field and ergometer tests for peak oxygen consumption (VO2 peak) (field=35±6 mL/kg/min vs. ergometer=33±7 mL/kg/min; p=0.491). However, significantly higher peak heart rate (field=173±5 bpm vs. ergometer=178±4 bpm; p=0.046) and respiratory exchange ratio (RER) (field=1.2±0.1 vs. ergometer=1.4±0.1; p=0.022) were found during the double poling ergometer protocol. There were no significant differences in blood lactate at baseline and after set one between protocols. However, a significantly higher lactate was found after set two (field=7±4 mmol/L vs. ergometer=12±5 mmol/L; p<0.001) and set three (field=8±3 mmol/L vs. ergometer=13±4 mmol/L; p=0.001) during the ergometer protocol compared to the field test. There were moderate correlations between the field and double poling ergometer for VO2 peak (r=0.79; p=0.035), and peak blood lactate (r=0.83; p=0.02). However, no correlations were found between protocols for peak heart rate (r=0.37; p=0.491) and RER (r=0.54; p=0.207). Results of this study suggest that the double poling ergometer is similar to a field test for evaluating VO2 peak in elite cross country sit skiing athletes; however, the ergometer test involves a higher heart rate and anaerobic component.

Thesis (M.S.)--East Carolina University, 2009. / Presented to the faculty of the Department of Exercise and Sport Science. Advisor: Timothy P. Gavin. Title from PDF t.p. (viewed June 4, 2010). Includes bibliographical references.

Thesis (M.S.)--Eastern Illinois University, 1987. / Includes bibliographical references (leaves 27-28).

No description available.

Thesis (M.S.)--Virginia Commonwealth University, 2008. / Prepared for: Dept. of Physiology and Biophysics. Title from title-page of electronic thesis. Bibliography: leaves 55-58.

Thesis (M.S.)--University of Texas at El Paso, 2009. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

A need exists to obtain accurate, reliable and valid data to assess the external and internal loads of soccer matches, especially as it relates to South African soccer teams. Consequently, the objectives of this study were firstly to determine the fatigue rates and patterns of a cohort of university-level soccer players during matches when using global positioning system (GPS) to quantify the high-intensity running performances in rolling 5-min periods. Secondly, to determine the influence of Yo-Yo intermittent recovery test level 1 (Yo- Yo IR1) determined training status of a cohort of university-level soccer players on fatigue patterns and rate during match play. Thirdly, to determine the positional-internal match loads of a cohort of university-level soccer players by making use of heart rates and the Yo-Yo IR1-determined threshold values. Lastly, to compare the match analysis results of different methods aimed at determining the external and internal match loads of a cohort of university-level soccer players. Selected groups of university-level soccer players (n = 10–13) were required to complete a 40-m maximum speed test and the Yo-Yo IR1 during a two-week period either before or after each analysed match. The heart rate (HR) values and GPS data of each player were recorded during league soccer matches. For the first and second objectives of the study players were categorised into three activity level categories (low, moderate and high) according to their activity levels of the first half of the match. Furthermore, their high-intensity running (> 3.7m/s) (HIR) was monitored in rolling 5-min periods. The low-activity group showed a small to moderate difference (p <0.05) in high-intensity running (HIR) at 5-min and 15-min after the peak period compared to the average 5-min period. The moderate-activity group showed a moderate difference (p <0.05) in HIR at 5-min after the peak period. The high-activity group showed moderate to large declines in distance covered between the first 15-min of the second half (103.9 m/min) compared to the first 15-min of the first half (122.5 m/min). They also showed small to moderate declines in HIR during the first 10-min of the second half (25.7 m/min) compared to the first half (34.1 m/min). The low-activity group showed a small decline in distance covered during the first 5-min of the second half (76.3 m/min) compared to the first half (87.7 m/min). Conversely the low-activity group showed a small to moderate increase in distance covered during the last 10-min of the second half (95.7 m/min) compared to the first half (84.4 m/min). The Yo-Yo IR1 was not significantly correlated with any of the variables associated with HIR. For the third objective of the study players’ heart rates that corresponded with the first and second ventilatory thresholds as obtained during a Yo-Yo IR1 were used to classify heart rates into low (LI HR zone), moderate (MI HR zone) and high-intensity zones (HI HR zone). Results showed that attackers spent more time in the LI HR zone (3386 s; 62%; p <0.05) than defenders (2155 s; 40%) and midfielders (2425 s; 42%). The attackers spent less time in the HI HR zone (260 s; 4%; p <0.05) than the defenders (964 s; 15%). Midfielders (2444 s; 44%) and defenders (2364 s; 41%) spent more time in the MI HR zone than attackers (1854 s; 44%). For the fourth objective of the study players’ individualised velocity and heart rate (HR) thresholds were determined from the 40-m maximum speed test and the Yo-Yo IR1. Results showed a large (r = 0.5; p ≤0.01) correlation between the time spent in the LIVZ (5017 ± 368 s) and the LI HR zone (2891 ± 1086 s), with the true correlation value that varied between moderate and large. Similarly, a moderate (r = 0.3; p ≤0.01) to large (r = 0.6; p ≤0.01) correlation was found between the relative (11.4 ± 3.7%) and absolute time (669 ± 223 s) spent in the MIVZ and the MI HR zone (41.0 ± 16.8% and 2253 ± 752 s). However, the true correlation value for the absolute time spent in the MI zone fell between the large to very large category, whereas the correlation for the relative time was small to moderate. There were no significant correlations (p ≤0.01) between the HIVZ and the HI HR zone. Although some correlations were found from the Spearman’s rank correlation, when adjusting for 2max O V• and Yo-Yo IR1 performance these correlations became non-significant. From these study results it is clear that the Yo-Yo IR1 and 40-m speed test show promise to be used as valid sports-specific field tests for determining ventilatory thresholds for each player, the heart rates that correspond to these thresholds and the different velocity thresholds. The authors therefore recommend that researchers use these methods in future to determine individualised HR and velocity zones in combination with the GPS analysis results to define both the internal and external match loads of soccer players. Results of these analyses could enable future coaches and sport scientists to develop match-specific conditioning programs that reflect both the internal and external demands of soccer matches / PhD (Human Movement Science), North-West University, Potchefstroom Campus, 2015