Running economy (RE) is defined as the rate of oxygen consumption at a given submaximal running velocity. Whilst the concept of running economy is well documented, little information is available about the to daily variation in RE, variation in RE within prolonged running bouts and the effects on RE of exercise-induced dehydration. Thus, the principal aim of this research was to investigate these aspects and attempt to contribute further knowledge and understanding of RE. The purpose of the first study (Chapter 4), was to investigate the daily variation in RE in twenty one habitually active Singaporean men (V0₂max = 51.6 ± 5.8 ml.kg⁻¹ min⁻¹). The RE was measured over three consecutive days during treadmill running at 3.33 m.s⁻¹, and at running speeds representing relative exercise intensities of 60% and 85% V0₂max (randomly assigned in a counterbalanced design). The running bouts were of 10 min duration at each speed, with 5 min rest between each running bout. The group mean (±SD) VO₂ during submaximal running at 3.33 m.s⁻¹ (82 ± 5.7% V0₂max) was 44.5 (±2.1), 43.8 (±2) and 44.2 (±2) ml.kg⁻¹ min⁻¹ for days one, two and three respectively. The mean coefficient of variation (CV) for RE at 3.33 m.s⁻¹ was 2.54 % (range = 0.24 - 5.41%). The group mean VO₂ during submaximal running at 60% and 85% VO₂max was similarly invariant over the three consecutive days. The results showed no differences in daily RE for the group (p > 0.05). The results suggest that for the individuals in this study RE does not change on a daily basis.

Extreme physical exertion is commonly associated with acute physiological changes in immune variables known to disturb host defences. Likely induced by the production of stress hormones (e.g., cortisol), partaking in ultra-endurance events with accompanying physiological stressors (e.g., environmental extremes, sleep deprivation and compromised hydration and (or) nutritional status) may amplify stress hormone responses and compromise immune status to a greater extent. To date, research investigating the impact of extreme physical exertion (e.g., ultra-marathon events) on physiological variables is extremely limited. More recently, the potential use of probiotics with known immunomodulatory effects may be considered an appropriate nutritional strategy to improve host defences and minimise and (or) prevent sub-clinical or clinically significant outcomes in active populations.

The purpose of the investigation was to study a programme of Progressive Reinforcement Training and to note the changes in performance in running 800 metres. Two secondary purposes were: 1. To study several physiological variables and to note changes after the Progressive Reinforcement Training. 2. To note certain psychological characteristics of the subjects. Nine students of a major secondary school in Vancouver participated in the study. The group trained on a Progressive Reinforcement Training Programme for seven weeks. The Cattell Junior-Senior High School Personality Questionnaire was administered to each individual of the group. The group was pre and post-tested on the following items: vertical jump; isometric leg strength; treadmill performance time; acid-base balance prior to and after the first and last training sessions. Time trials were recorded prior to, during and after the training programme. The results of the Personality Factor Questionnaire indicated that the runners tended to be happy-go-lucky, conscientious, doubting and self-sufficient. All members of the group were classified as positive achievers. The results showed that there was no statistically significant improvement in the vertical jump score (t=0.076). There were significant differences at the .05 level of significance on the following isometric strength scores: Left Knee Flexion (t=5.69); Right Knee Flexion (t=4.4l); Left Hip Flexion (t=2.58); Right Hip Flexion (t=5.30); Left Hip Extension (t=7.32); Right Hip Extension (t=4.98). However, no significant gains were made on the Left Knee Extension (t=2.07) or Right Knee Extension (t=2.15). Within the Progressive Reinforcement trained group, it was found that treadmill performance times were significantly increased (t=9.02). The results of the blood analyses indicated that a general trend existed in which the pH values decreased significantly as a result of training. After the Progressive Reinforcement Training, it was noted that there were significant improvements in times for running 800 metres (t=6.84). / Education, Faculty of / Curriculum and Pedagogy (EDCP), Department of / Graduate

To determine whether running imposes an additional iron cost on the female athlete, the response to an identical iron supplementation regime (200 mg elemental iron/day for 12-13.5 weeks) was assessed in two groups of iron deficient females classified as either runners (n=11) or non-runners (n=11). Criteria for selection was iron deficiency (serum ferritin ≤ 20 ng/ml) with an absence of anaemia (haemoglobin ≥12 g/dl). The response to therapy was evaluated on the basis of changes in serum ferritin and haemoglobin levels. Dietary intakes, physical activity and menstruation were monitored by all subjects. Runners averaged 32±8 miles running/week while the non-runners remained relatively sedentary during the supplementation period. Menstrual losses were similar in both groups. There was no significant difference in absorbable iron intake between the groups (p=0.10) and intakes ranged from 0.4-2.6 mg absorbable iron /day. Inadequate iron intakes were clearly demonstrated in 62% of the dietary records. As expected, there was a significant improvement in iron status over the period of oral iron therapy. Although the average overall change in serum ferritin for non-runners was 37.1 ng/ml compared to 26.6 ng/ml for the runners, this was not statistically significant (p=0.29) due to the very large interindividual variability in the change scores. Similarly, there was no significant difference in haemoglobin between the groups when averaged over time (p=0.81) and runners and non-runners demonstrated a similar pattern of change in haemoglobin over the course of supplementation. Regardless of their athletic practices, all females in their reproductive years appear to be at high risk of iron deficiency, primarily due to inadequate nutrition. Regular blood donation was also recognized as a potential contributing factor to the observed iron deficiency in these females, particularly in the non-runners. Because iron deficiency is undesirable for optimal health and well-being, recognition and prevention is highly recommended. Regular monitoring of iron status is particularly important in high performance athletes since a minor deficiency can potentially hinder peak performance and/or lead to the development of anaemia. / Education, Faculty of / Curriculum and Pedagogy (EDCP), Department of / Graduate

No description available.

Running has been a popular sport because of convenience and health benefits. Fatigue among recreational runners may alter running mechanics, thereby increasing the risk for injury. The purpose of this study was to evaluate changes in lower extremity biomechanics throughout a 3.1 mile (5K) run. Ten male and ten female participants wore reflective markers to capture contralateral pelvic drop, knee adduction, knee abduction, and hip adduction. Participants ran 3.1 miles (5K) on a treadmill at a self-determined pace. A two-way, repeated measures ANOVA was conducted to capture the within-subject data across time and between-subject comparing differences in gender. Females had significantly greater contralateral pelvic drop but it did not change over time. Knee abduction angles significantly declined over the five observations. Gender differences and effects of distance can alter the biomechanics in recreational runners. More research is needed to identify predisposing factors to the development of chronic running injuries. / North Dakota State University. Department of Health, Nutrition, and Exercise Sciences

Over the past decade long distance marathon running has become an important recreational activity. There is evidence that males with high levels of physical activity have some impairment of fertility. In order to investigate this further, 24 male marathon runners were studied over a period of a year. Each runner was assessed at regular intervals using hormonal profiles, anthropomorphic indices and semen evaluation. The training time and distance run increased progressively over the first five months of the study as the runners prepared for the Two Oceans marathon. Analysis of the serum hormonal profiles in this longitudinal study showed that the prolactin level increased when comparing the initial study month with the rest of the year and the progesterone level decreased. However the luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone and estradiol (E2) levels remained unchanged. When the runners were divided into a high and low training group according to the distance run in the preceding week, the only significant difference was the lower mean serum FSH level in the high training group. A decrease in semen volume was demonstrated as the training time increased. This trend was reversed as the runners' training decreased after the Two Oceans marathon. The percentage of morphologically normal spermatozoa showed an initial significant decrease in the first month of training. However, no significant difference was observed throughout the rest of year. An overall downward trend in semen motility in the first 5 months of the study was shown but this was only significant if the first and fifth study months were compared. The decrease in semen motility coincided with the period of maximum training. Since patients with an adequate sperm count but decreased motility have impaired fertility this finding is of considerable importance. In addition to the decrease in motility, there was a decrease in the percentage of morphologically normal spermatozoa when the initial month of low physical activity (December) was compared to all of the subsequent months analysed. This, too, is an important finding as the percentage of morphologically normal spermatozoa correlates directly with fertilisation and pregnancy rates. When the results were analysed in the high and low training months there was a significant difference in mean semen count and semen morphology. The mean count was higher in the high training group and this group also had a significantly higher normal morphology. However, there was no significant difference in semen volume and motility in the high and low training groups.

Pseudoephedrine is an over-the-counter drug commonly used as a decongestant, but also thought to have ergogenic effects. The World Anti-Doping Agency (WADA) has prohibited large doses (> 150 μg∙ml-1) of pseudoephedrine, while the National College Athletic Association (NCAA) does not include it on the banned substance list. The purpose of this study was to examine the effect of body weight dosing of pseudoephedrine on 800-m run times of NCAA female runners. Fifteen NCAA female track runners volunteered to participate in the randomized, double blind, crossover design. In trials that were a week apart, participants were given both 2.5 mg∙kg-1 pseudoephedrine and a placebo. Ninety minutes post-ingestion, participants completed an 800-m individual time trial on an indoor track. Finishing time was recorded with an automated video timing device. Heart rate and anxiety state scores were recorded immediately after each trial. Finally, a urine sample was taken from 5 participants about 2 hr post-ingestion. Placebo and pseudoephedrine running times were compared using a iv paired t test. Heart rate and anxiety state scores were also compared using a paired t test. Fourteen runners completed both trials and one was an outlier, giving thirteen participants used for statistical analysis. Despite being dosed (144 mg ± 17 mg) well above normal therapeutic levels, there was no significant difference (p = 0.92) in 800-m times between the placebo (2:39.4 ± 9.6) and pseudoephedrine (2:39.4 ± 9.6) trials, in post-exercise heart rate (p = 0.635, pseudoephedrine = 177.9 ± 14.5 beats∙min-1, placebo = 178.4 ± 18.5 beats∙min-1), or in anxiety state levels (p = 0.650, pseudoephedrine = 38.4 ± 11.6, placebo = 38.1 ± 8.8). A 2.5 mg∙kg-1 dose of pseudoephedrine had no effect on 800-m run times in NCAA female runners, and did not raise urine levels above 150 μg∙ml-1. This raises the question as to why pseudoephedrine is a specified prohibited substance by WADA. (49 pages)

The objective of this research was to investigate relationship between dissociative and associative cognitive strategies for coping with the discomfort of running and running performance. Subjects were volunteers enrolled in two Dynamic Fitness classes which were taught during Spring Quarter, 1980, at Utah State University. Class A consisted of 36 subjects (24 male, 12 female) and Class B consisted of 28 subjects (13 male, 15 female). All pretest, posttest, and treatment procedures were conducted during the class's respective regularly scheduled meeting times. Subjects completed a 2.75 mile, timed, pretest run and were systematically assigned to one of three groups based on pretest time: 1) Control, 2) dissociation training group, and 3) association training group. Two training sessions were conducted to provide instruction in developing and using a cognitive strategy for both dissociation and association groups. Control group subjects also met with the researcher twice, but no instructions for development and use of a cognitive strategy were given. A posttest 2.75 mile, timed run was completed and subjects completed a posttest questionnaire. Due to differences in procedures for subject recruitment and weather conditions for the posttest run, data from Class A and B were analyzed separately. Analysis of covariance revealed no statistically significant relationship between teaching of a cognitive strategy and running time for either class. Posttest questionnaire information was also analyzed. For both classes, statistically significant negative correlations were found between difference for pretest/posttest timed runs and dissociation points as reported on the posttest questionnaire. Also t-tests of independent means showed that association group subjects reported significantly higher levels of association than control group subject for both classes. It was suggested that although training may have increased the reported use of a cognitive strategy it was not an important factor in running performance. The researcher suggested, instead, that willingness to exert oneself may have been the primary factor in determining performance in relationship to physical limitations.

No description available.