Thesis (M.S.)--University of North Carolina at Greensboro, 2006. / Title from PDF title page screen. Advisor: Jennifer Etnier; submitted to the School of Health and Human Performance. Includes bibliographical references (p. 37-43).

Thesis (M.S.)--Eastern Illinois University. / Vita. Includes bibliographical references (leaves 40-42).

Thesis (M.A.)--Eastern Illinois University. / Includes vita. Includes bibliographical references (leaf 27).

Skeletal muscle damage can lead to cell death and the subsequent release of intracellular molecules. To investigate whether molecules from skeletal muscle can interact with the heart, the Langendorff isolated heart preparation was used to assess cardiac function, while NF-κB and AP-1 activation were assessed by EMSA to observe inflammatory status. Hearts were perfused for 75 min with 1 μg/ml of either soleus, white gastrocnemius (WG), or heat stressed white gastrocnemius (HSWG) skeletal muscle homogenate and a decreased LVDP, +dP/dt and –dP/dt were observed when compared to untreated (control) hearts. Greater early and late decreases in cardiac function were observed in hearts treated with HSWG and soleus muscle homogenates, respectively. No alterations in NF-κB or AP-1 activation were detected. These data suggests the contents of skeletal muscle are capable of interacting with the heart and altering contractile function in a fibre type specific manner, possibly related to muscle HSP content.

Skeletal muscle damage can lead to cell death and the subsequent release of intracellular molecules. To investigate whether molecules from skeletal muscle can interact with the heart, the Langendorff isolated heart preparation was used to assess cardiac function, while NF-κB and AP-1 activation were assessed by EMSA to observe inflammatory status. Hearts were perfused for 75 min with 1 μg/ml of either soleus, white gastrocnemius (WG), or heat stressed white gastrocnemius (HSWG) skeletal muscle homogenate and a decreased LVDP, +dP/dt and –dP/dt were observed when compared to untreated (control) hearts. Greater early and late decreases in cardiac function were observed in hearts treated with HSWG and soleus muscle homogenates, respectively. No alterations in NF-κB or AP-1 activation were detected. These data suggests the contents of skeletal muscle are capable of interacting with the heart and altering contractile function in a fibre type specific manner, possibly related to muscle HSP content.

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.

There is no abstract available for this dissertation.

Background: Fractures are a major health concern for older adults, especially for those with osteoporosis or low bone mineral density (BMD). Physical activity and exercise can be important self-management strategies for older adults with osteoporosis or low BMD to prevent fractures. Objectives: This study examined the physical activity and exercise levels of older adults with low BMD and determined the proportion of individuals meeting the Canadian Physical Activity Guidelines. As well, this study characterized perceived individuals’ barriers to exercise and their willingness to pay for different methods of delivering exercise information. Secondary goals of this study were to investigate correlates of aerobic exercise and factors associated with meeting moderate- to vigorous-intensity aerobic physical activity guidelines. Methods: Individuals aged 50 years or older with a self-reported diagnosis of low BMD were recruited from the Canadian Osteoporosis Patient Network (COPN) and an osteoporosis public education event. Questionnaires were distributed online and through mail to individuals interested in participating. Participants were asked about the amount of time they spent doing moderate- and vigorous-intensity physical activity (MVPA) and the frequency at which they did strength and balance training per week. Also, participants were asked about potential barriers to exercise that they perceive, the strength at which they perceived those barriers at, and their interest in and willingness to pay (WTP) for different methods of delivering exercise information. Information about different factors affecting exercise behaviour such as risk perception, intention to exercise, and exercise self-efficacy were collected as well. Results: The total number of participants included in this study was 130 (mean [SD] age 66.32 [8.81] years). The mean (SD) time spent doing MVPA per week reported by participants was 831.35 (1065.43) minutes. The mean (SD) days per week that participants reported doing strength and balance training were 1.90 (1.66) and 1.36 (1.84), respectively. Sixteen individuals (12.3%) did not meet the guideline of engaging in at least 150 minutes of MVPA per week. Forty-one participants (31.5%) did not report doing any strength training and sixty-five individuals (50%) did not report doing any balance training. The most prevalent barriers to exercise that were reported was having no enjoyment for exercise (51.2%) , having no company to exercise with (47.2%), and health-related problems (37.5%). Although a majority of participants expressed interest in all methods of delivering exercise information, the mean WTP for a group exercise class and for training one-on-one with a certified personal trainer was lower than the suggested amounts that they would normally cost. Factors associated with meeting MVPA recommendations were intention to exercise (p = 0.03), exercise self-efficacy (p = 0.03), and strength of perceived barriers (p = 0.02). Conclusion: Many older adults with low bone mineral density are not meeting established physical activity guidelines. Greater measures need to be taken in promoting strength and balance training among these individuals. Addressing barriers to exercise may be an effective strategy to encourage individuals with low bone mineral density to become more active.

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.

Aging is characterized by a progressive impairment of cardiac structure and function. The cardiac remodeling involves loss of cardiac myocytes, reactive hypertrophy of the remaining cells, and increased extracellular matrix (ECM) and fibrosis in the aging heart. In contrast, exercise training not only improves cardiac function, but also reduces the risk of heart disease. However, the ability of exercise training to modulate ECM and remodeling in the aging heart remains unknown. Therefore, the purpose of this study was to determine the effects of exercise training on ECM remodeling in the aging heart. We hypothesized that (1) exercise training would attenuate age-related changes in left ventricle morphology including extramyocyte space and collagen contents, and (2) exercise training would ameliorate age-induced changes in ECM-related factors including MMPs, TIMPs, TNF-α, TGF-β1, and α-SMA in the heart. Three and 31 month old Fischer 344 × Brown Norway F1 hybrid rats were assigned to four groups: young sedentary (YS), young exercise-trained (YE), old sedentary (OS), and old exercise-trained (OE). Exercise training groups walked briskly on a treadmill for 45 min/day (12° incline) at 20m/min (young) or 10 m/min (old), 5 d/wk for 12 wk. We found that endurance exercise training might ameliorate the ageinduced increase in extramyocyte space and collagen contents of the left ventricle. Exercise training might protect against age-induced fibrosis by increasing MMP-2, MMP-14 in the soluble fraction and MMP-1, MMP-3, MMP-14 in the insoluble fraction of old rat hearts. Conversely, exercise training might reduce the fibrosis by decreasing TIMP-1 in the soluble fraction of old rat hearts. Further, exercise training reduced potential upstream pro-fibrotic mediators including TNF-α and TGF-β1 in the aging rat hearts. These results are the first to demonstrate that exercise training has a protective effect against age-induced extracellular collagen matrix remodeling in the aging heart, associated with increased MMP-1, -2, -3, -14 and decreased TIMP-1, TNF-α, and TGF- β1.