Thesis (M.S.)--Purdue University, 2003. / Includes bibliographical references (leaves 41-49).

Thesis (M.A.)--University of North Carolina at Chapel Hill, 2003. / Includes bibliographical references (leaves 55-57).

Thesis (M.A.)--University of North Carolina at Chapel Hill, 2004. / Includes bibliographical references (leaves 76-79).

The number of South African endurance athletes is increasing yearly. However, very little research has been done on non-elite South African endurance athletes. Due to the length and nature of endurance sport and especially extreme endurance sport, athletes have to employ more self-motivating strategies for longer periods to perform well. One factor that increases athletes’ stress levels is the environment within which they are participating. These environments can and usually are very harsh, such as extreme heat or cold. However, the motivational- and coping strategies used by athletes specifically in extreme endurance events have not been studied to a great extent (Weinberg&Gould, 2003). The aim of this study is to determine the coping- and motivational strategies that non-elite athletes use to overcome environmental factors during endurance events. A qualitative approach was used where 53 non-elite endurance athletes completed a questionnaire and interviews. Through analysis of the data it emerged that environmental factors are perceived to have a physical and mental impact on performance. The perception of this impact differs and can be positive, negative or neutral depending on situational factors. Motivational strategies that are employed during endurance events are the result of two factors: focus of motivation and source of motivation. By combining these two factors, four motivational strategies were identified: positive-internal, positive-external, negative-internal and negative-external of which positive-internal was most frequently used, followed by negative-internal, positive-external and negative-external. Endurance athletes used all three coping strategies that were identified in the literature. The most frequently used strategy was to remove the source of the stress, followed by strategies that changes the athlete’s perception of the stressor, and lastly strategies that focuses on the symptoms of the stress. Endurance athletes perceive themselves able to overcome the challenges of endurance events. However, this ability must constantly be tested by participation in endurance sport or other stressful situations. Previous successful participation in endurance events or other stressful situations leads to an increase in positive self-perception of own abilities, as well as an increase in performance in endurance events. / Thesis (DPhil (Human Movement Science))--University of Pretoria, 2007. / Biokinetics, Sport and Leisure Sciences / DPhil / unrestricted

Thesis (MSc)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: A 5 km cycling time trial (TT) demands high, sustained muscle power output and substantial oxidative and glycolytic energy delivery. The aims of this study were to firstly use the novel approach of using Peak Sustained Power Output (PSPO) as a predictor of cycling performance for variable fixed-workload testing and 5 km time trialing and whether oral creatine supplementation would affect 5 km time trial performance and metabolism. The effect of oral creatine supplementation with 20 g/day for 7 days on 5 km time trial performance and metabolism after a random-variable workload protocol (stochastic test) was investigated in a single-blind placebo controlled study. Thirteen trained male cyclists volunteered for the study that was approved by the University of Stellenbosch Research Ethics Committee. We hypothesized that Cr supplementation would affect time trial performance as well as the appearance of breakdown products of adenine nucleotides in the plasma. Baseline: the subjects' peak power output was measured and they underwent a baseline stochastic test followed immediately by a 5 km time trial (STI) and on a different day, a single 5 km time trial test (Tl) was undertaken. Study 1: In the following week the subjects repeated the stochastic test with 5 km time trial (ST2) and on a different day a 5 km time trial (T2). During T2 blood samples were taken at regular intervals as well as during recovery. A muscle biopsy was taken after T2 in the recovered state. The major performance predictors were the 5-km time trials (TTl and TT2) with a coefficient of variation between the thirteen trained male cyclists of 0.6%. The 5 km time trials in the fatigued state (STI and ST2) had a coefficient of variation of 0.7%. Results: There was a significant difference between 5 km TT performed fresh and 5km TT performed fatigued (P=0.0001). The decrement in time ranged between 1.0 sec to 38.0 sec. The relationship between two different high intensity endurance performance tests: PSPO and 5 km TT (TT mean) had a correlation ofr=-0.79 P<O.OI. The correlation between PSPO and the 5 km TT performed in the fatigued condition (ST mean) was r= -0.60 P<0.05. There was also a relationship between age and PSPO (F 0.73; P<0.05). Age showed a good negative relationship with TT mean (F- 0.71; P<0.05). Mass and PSPO were also correlated (FO.85; P<O.OI). Plasma lactate concentrations were significantly different from rest at all other time points P<O.OOOIup to 20 minutes post-exercise. Hypoxanthine (P<O.OOOI)and urate (P=O.05) concentrations were also significantly different from rest at all other time points. There was a significant change in plasma hypoxanthine concentrations over time (P<0.0001). There was a significant correlation between plasma lactate concentration at time 0 in recovery and % Myosin Heavy Chain (MHC) I (FO.59, P<0.05) and % MHC na (F -0.61, P<0.05). Area under the curve for hypoxanthine showed significant relationships of F -0.53 (P=O.05) and F 0.56 (P<0.05) respectively for %MHC I and %MHC ITa. Study 2 - Supplementation: following T2 the subjects received Cr or placebo powder containing sachets to be ingested 4 times daily for the next week with carbohydrate also provided. Post-supplementation testing: the subjects returned and conducted another variable fixedworkload test with 5 km time trial (ST3) as well as a single 5 km time trial (T3). They once again underwent the same blood sampling routine and had another muscle biopsy in the rested state. The average of ST1 and ST2 was used as the major measure for performance under fatigued conditions and TTmean. Results: there was a significant difference between 5 km TT performed fresh and 5 km TT performed fatigued (P=0.0001). Plasma lactate, hypoxanthine and urate samples were taken at the postloading 5 km time trial (TT3). The levels of these plasma metabolites were compared to the concentrations of those sampled at TT2 and between the creatine and placebo groups. The plasma hypoxanthine levels were significantly different from rest for both the creatine and placebo groups (P<0.0001). Plasma urate had significant change in concentrations over the time points (P<0.005). Another significant difference was found between the creatine and placebo groups for the pre-and post tests conducted (P<0.005). The creatine group showed a non-significant increase (7%) in mean total intramuscular creatine concentration. No significant differences were found in the mean values for total nucleotide concentration pre- and post loading in the creatine and placebo groups. Conclusions: The 5 km performance test resulted in high values for plasma lactate, hypoxanthine and urate, an indication of fatigue induced by this performance test. Oral creatine supplementation did not improve performance significantly in the variable fixedworkload protocol 5 km time trials or the individual 5-km time trials and had an effect on adenine nucleotide metabolism in both the variable fixed-workload protocol 5-km time trial and individual 5 km time trial performance tests. / AFRIKAANSE OPSOMMING: Die 5 km fietsry tyd toets (TT) verg hoëvolgehoue, spierkrag en wesenlike oksidatiewe en glikolitiese energie verskaffing. Die doelwitte van hierdie tesis was eerstens om 'n nuwe fietsergometer toets te ontwerp vir die voorspelling van kompetisie prestasie. Die toets was 'n veranderlike, voorafvasgestelde werkladingstoets (VVWT). Dit is vergelyk met 'n maksimale volgehoue kraguitsetingstoets (MVKT) en 'n 5 km TT. Daarna is bepaal ofkreatien supplementasie 'n effek sou hê op enige van hierdie oefeningstoetse of metabolisme tydens die 5 km TT. Die supplementasie eksperiment was 'n enkelblinde, plasebo-gekontroleerde studie ontwerp. Dertien manlike fietsryers het vrywilliglik deelgeneem. Resultate: Daar was 'n statisties betekenisvolle verskil tussen die 5 km TT wat vars onderneem is en die wat direk na die VVWT onderneem is (P=O.OOOl). Daar was ook 'n betekenisvolle korrelasie tussen die twee verskillende hoë intensiteit korttydsvak oefeningstoetse (r=-0.79 P<O.Ol vir TT en MVKT). Plasma laktaat konsentrasies was betekenisvol verhoog met vergelyking van die monsters geneem tydens rus en all ander onteledings tydspunte (P<0.0001) tot en met 20 minute na oefening. Hypoxantien (P<O.OOOl) en uraat (P=0.05) konsentrasies was ook betekenisvol verskillend van rus by alle ander tysdpunte. Daar was 'n betekenisvolle korrelasie tussen plasma laktaat direk na oefening en die % Myosien Swaarketting (MIlC) I (r=0.59, P<0.05) en % MHC ITa (r= - 0.61, P<0.05). Studie 2 - Na supplementasie was daar geen verskil in oefeningsprestasie nie maar wel in plasma metaboliet waardes van nie. Gevolgtrekkings: Die 5 km TT het baie hoë waardes vir plasma laktaat tot gevolg gehad, asook hypoxantien en uraat, 'n indikasie van die hoë mate van vermoeienis deur hierdie oefeningtoets berwerkstellig. Kreatine supplementasie kon nie oefeningsprestasie verbeter nie.

The purpose of this study was to examine the effect of extreme exercise on vitamin B-6 metabolism and urea nitrogen. Nine men and five women completed two 5-day trials; Trial 1 (T1) included a 50-km ultramarathon on day 4 and during Trial 2 (T2) subjects were "inactive" on day 4. During both trials, subjects consumed a diet providing men 2.0 and women 1.5 mg of vitamin B-6. With the exception of the ultramarathon, T1 activity was replicated during T2. Twenty four-hour urine collections were completed and blood was drawn pre-race (pre), mid-race (mid), post-race (post) and 60 minutes post race (P-60). On the inactive, day blood was drawn at the same intervals. Plasma was analyzed for pyridoxal 5'-phosphate (PLP), pyridoxal, 4-pyridoxic acid (4-PA), urea nitrogen (PUN), creatinine, albumin, glucose, and lactate concentration and alkaline phosphatase activity. Urine was analyzed for 4PA, creatinine, and total urinary nitrogen (TUN). During T1, compared to pre, plasma PLP concentration increased 17% at mid, decreased 5% by post, and 19% by P-60. During T2, plasma PLP concentration decreased 13% pre to P-60. During T1, plasma 4-PA concentration increased 135% and the percent dietary vitamin B-6 that was excreted as urinary 4-PA the day of the ultramarathon was higher than that excreted the day before and the day after. During T1, from pre to post mean PUN concentration increased 36.9%, and the average rate ofincrease from pre to mid, mid to post, and post to P60 was 0.5, 1.75, and 2 mg/dL/hour, respectively. During T1 on days 3, 4, and 5,88%, 100%, and 95% of nitrogen intake was excreted in the urine compared to 86%, 83%, and 84% for the same days during T2. The day of the ultramarathon, 24-hour TUN excretion was 2 g higher than the previous day. Extreme exercise of greater than six hours initially increases the plasma concentration of PLP but ultimately results in a significant decrease in plasma PLP, an increase in plasma 4-PA, and an increase in percent of dietary vitamin B-6 (as 4-PA) excreted in the urine. Additionally, the rate of change in PUN inoeases as duration increases. / Graduation date: 2001

No description available.

Little is known about the strain and consequences of very prolonged and sustained exercise lasting multiple days. This thesis comprises two multi-day exercise field studies and a 24-h, controlled-trial field/laboratory study. The field studies were undertaken using international adventure races (2003 and 2004 Southern Traverses: 86-120 h) to profile exercise intensity and associated physiological and psychophysical strain, and physical and cognitive performance. The 2003 study showed that exercise intensity (from heart rate range) averaged 64% during the first 12 h, dropped to 41% by 24 h, and remained so thereafter. Body core temperature (gastrointestinal pills), throughout racing (n=8) was relatively stable (min 36.0�C and only briefly >39�C), despite widely varying endogenous and exogenous thermal stress. Blood samples obtained before (n=34), during (n=11) and after (n=34) racing revealed a large plasma volume expansion (24%), with stable [sodium]plasma (n=6). Acute (15-30 h) and chronic (96-120 h) elevation of neutrophil, monocyte and lymphocyte numbers were observed across the race. Standardised exercise tests (rest, 25 and 50% peak power output (PPO)) before and after racing (n=9) revealed an extreme shift toward fat utilisation, consistent with lowered fat mass (11%; n=44) and high [free fatty acids]plasma (up 370%; n=9) at race-finish, although [HAD]muscle was unchanged. Muscle glycogen was only 50% lower post-race (290 nmol�kg⁻�d.w.). Complex cognitive performance (Stroop test) impairment was attenuated during 50% PPO post-race. Perceived exertion uncoupled from HR at standardised workloads. Explosive power (jump test; n=24) and anaerobic power (30-s Wingate; n=27) were modestly (<10%) impacted. Strength reduction of arms (11%) and legs (17%) was equivalent (p=0.17). The 2004 study (n=4) involved dissimilar terrain, vegetation, and sequence of exercise modes, yet the profile of exercise intensity was similar: first 12 h 65%, then 45% by 24 h and thereafter. Thus, athletes reliably attain sustainable, low-to-moderate exercise intensity by 24 h. Plasma volume, neutrophil and monocyte responses were reliable across races, whereas lymphocytes were not. Plasma [IL-6] and [S100β] were elevated, substantially in some individuals (IL-6: 223 pg�mL⁻�; S100β: 113 pg�mL⁻�), during racing. A 24-h adventure race simulation (n=9) was then undertaken to investigate physiological and psychophysical factors influencing exercise intensity, autonomic function and orthostatic tolerance. Tests were at 0, ~7, ~15 and 24 h. The 24-h HR profile matched that observed during racing: first 12 h 58% (including 3-h testing), remainder 41%. The shift toward fat utilisation was almost complete within 7 h, and similar to that following 2003 race. The perceived exertion-to-HR uncoupling was also similar; being complete within 15 h. Plasma [noradrenaline] for rest and 12-km�h⁻� run was elevated post-simulation. Plasma [IL-6] peaked by 7 h, although not as high as field observations. The timeframe of metabolic change and perceived exertion uncoupling coincided with that of pace reduction, and may be important regulatory components of very prolonged exercise intensity. Orthostatic intolerance was evident during the simulation (n=6/9), as was cerebral hypo-perfusion (15 h & 24 h). Autonomic function (baroreflex sensitivity, sympathetic activation, parasympathetic withdrawal) was altered only at 7 h, whereas postural-induced hypotension (via impaired venous response) and hypocapnia were always present.

Breast cancer is the most common cancer in North America (American Cancer Society [ACS], 2012; Canadian Cancer Society [CCS], 2012). Women diagnosed with breast cancer undergo a traumatic experience that disrupts their quality of life (Holmberg, Scott, Alexy, & Fife, 2001). In the psychological domain of quality of life, body image is disrupted due to the changes associated with breast cancer surgeries and treatments (Hormes et al., 2008). This is important because breast cancer survivors’ quality of life is an essential part of their survivorship (Kaiser, 2008). Evidence has suggested that physical activity shows improvements in body image, survival rates, and decreased risk of mortality (Schmitz, 2011). Furthermore, a unique form of physical activity associated with breast cancer that has risen among this population is endurance sporting events, such as dragon boating and running (Canadian Breast Cancer Foundation [CBCF], 2012; Parry, 2008). Endurance sporting events are common among breast cancer organizations to raise funds and spread breast cancer awareness (Kaiser, 2008). However, they also provide breast cancer survivors with a fun and healthy sporting environment to explore their body image as well as shared experiences with other breast cancer survivors. Researchers have shown endurance sporting events to be a comfortable environment for breast cancer survivors to allow their experiences to unfold (McDonough, Sabiston, & Crocker, 2008; Sabiston, McDonough, & Crocker, 2007). Due to the uniqueness of each woman’s breast cancer experience, it is important to explore their body image experiences to understand their personal stories and provide meaning to enhance their quality of life as breast cancer survivors. The general purpose of this dissertation is to explore the body image and camaraderie experiences of breast cancer survivors in endurance sporting events. Furthermore, the guiding research question of this dissertation is: What are the body image and camaraderie experiences of breast cancer survivors participating in endurance sporting events? Narrative research methodology will be used to provide insight into this research question across two studies. To address the gap in the literature, Study 1 of my dissertation provided narratives of three breast cancer survivors’ body image experiences as they trained for and participated in the CIBC Run for the Cure 5k. Two individual semi-structured interviews, prolonged engagement, and blogging were used as sources of data collection over a time period of 10 weeks. Data analyses led to the emergence of three themes: "new normal", goal setting, and camaraderie. Camaraderie, representing the shared breast cancer survivors’ experiences that allowed the women to focus on their physical capabilities, accept their bodies, and create an overall body image experience, was a particularly salient theme to the women throughout their training. Hence, the purpose of Study 2 was to explore the camaraderie narrative experiences of breast cancer survivors in a season of dragon boating. Focus group interviews and creative practices were conducted with a core group of 11 breast cancer survivors over a six month time period. The women defined camaraderie as fellowship, teamwork, and support shared between women with breast cancer experiences. Subsequent data analyses resulted in five themes: attention please, paddles up, take it away, hold the boat, and reach. Overall, camaraderie was shown to be crucial to the survivorship of the women, as social experiences are an important component to life after breast cancer. The findings were written as a collective (e.g., camaraderie) narrative. Taken together, these two studies demonstrated that body image and camaraderie are important components to breast cancer survivors’ participation in endurance sporting events. More specifically, both studies informed the literature by describing the relationship between the camaraderie and body image experiences for the women involved in both the CIBC Run for the Cure 5k and a season of dragon boating. Camaraderie was the motive that created an overall positive body image experience for the women. Furthermore, endurance sporting events associated with breast cancer formed natural, comfortable, and safe environments for the women to express their experiences. In addition, camaraderie seemed to be a key process through which the women were able to accept their bodies and the body-related changes that resulted from cancer. In both studies, breast cancer survivors’ participation in endurance sports included camaraderie experiences that led to fulfilling the physical, emotional, and social needs as a mode for the women to move beyond their breast cancer experiences.

Little is known about the strain and consequences of very prolonged and sustained exercise lasting multiple days. This thesis comprises two multi-day exercise field studies and a 24-h, controlled-trial field/laboratory study. The field studies were undertaken using international adventure races (2003 and 2004 Southern Traverses: 86-120 h) to profile exercise intensity and associated physiological and psychophysical strain, and physical and cognitive performance. The 2003 study showed that exercise intensity (from heart rate range) averaged 64% during the first 12 h, dropped to 41% by 24 h, and remained so thereafter. Body core temperature (gastrointestinal pills), throughout racing (n=8) was relatively stable (min 36.0�C and only briefly >39�C), despite widely varying endogenous and exogenous thermal stress. Blood samples obtained before (n=34), during (n=11) and after (n=34) racing revealed a large plasma volume expansion (24%), with stable [sodium]plasma (n=6). Acute (15-30 h) and chronic (96-120 h) elevation of neutrophil, monocyte and lymphocyte numbers were observed across the race. Standardised exercise tests (rest, 25 and 50% peak power output (PPO)) before and after racing (n=9) revealed an extreme shift toward fat utilisation, consistent with lowered fat mass (11%; n=44) and high [free fatty acids]plasma (up 370%; n=9) at race-finish, although [HAD]muscle was unchanged. Muscle glycogen was only 50% lower post-race (290 nmol�kg⁻�d.w.). Complex cognitive performance (Stroop test) impairment was attenuated during 50% PPO post-race. Perceived exertion uncoupled from HR at standardised workloads. Explosive power (jump test; n=24) and anaerobic power (30-s Wingate; n=27) were modestly (<10%) impacted. Strength reduction of arms (11%) and legs (17%) was equivalent (p=0.17). The 2004 study (n=4) involved dissimilar terrain, vegetation, and sequence of exercise modes, yet the profile of exercise intensity was similar: first 12 h 65%, then 45% by 24 h and thereafter. Thus, athletes reliably attain sustainable, low-to-moderate exercise intensity by 24 h. Plasma volume, neutrophil and monocyte responses were reliable across races, whereas lymphocytes were not. Plasma [IL-6] and [S100β] were elevated, substantially in some individuals (IL-6: 223 pg�mL⁻�; S100β: 113 pg�mL⁻�), during racing. A 24-h adventure race simulation (n=9) was then undertaken to investigate physiological and psychophysical factors influencing exercise intensity, autonomic function and orthostatic tolerance. Tests were at 0, ~7, ~15 and 24 h. The 24-h HR profile matched that observed during racing: first 12 h 58% (including 3-h testing), remainder 41%. The shift toward fat utilisation was almost complete within 7 h, and similar to that following 2003 race. The perceived exertion-to-HR uncoupling was also similar; being complete within 15 h. Plasma [noradrenaline] for rest and 12-km�h⁻� run was elevated post-simulation. Plasma [IL-6] peaked by 7 h, although not as high as field observations. The timeframe of metabolic change and perceived exertion uncoupling coincided with that of pace reduction, and may be important regulatory components of very prolonged exercise intensity. Orthostatic intolerance was evident during the simulation (n=6/9), as was cerebral hypo-perfusion (15 h & 24 h). Autonomic function (baroreflex sensitivity, sympathetic activation, parasympathetic withdrawal) was altered only at 7 h, whereas postural-induced hypotension (via impaired venous response) and hypocapnia were always present.