Includes abstract. Includes bibliographical references (leaves 69-74).

Includes bibliographical references.

Bibliography: leaves 67-73.

Includes bibliographical references (leaves 87-103). / Ultra-endurance events, in particular Ironman Triathlons, are physically very demanding for the competitors. There is a large body of evidence showing the Upper Respitory Tract Symptoms (URTS) are very common in athletes in the 2-week period after such an event. However, there is no definitive explanation as t the exact cause of mechanism for the development of post-race URTS. The aims of this study were: (1) to determine the incidence of post-race URTS in triathletes competing in an Ironman Triathlon; (2) to identify clinical and immunological factors that are associated with the development of post-race URTS in these triathletes. In this prospective cohort study, 99 triathletes entering the 2006 South African Ironman Triathlon were recruited as subjects. All the subjects completed a validated questionnaire in the one to three days before the race (during registration). The questionnaire contrained sections on demographics, training history and previous performances, common general medical conditions that they may have experienced, and a detailed section pertaining to respiratory tracgt symptoms (RTS) and allergies. At registration, each subject had a blood sample taken for analysis of cytokines representing mainly a TH1 response (IL-2, and IL-12) (cell mediated immunity) and a TH2 response (IL-4, IL-6, IL-10) (humoral immunity), as well as a saliva sample (for salivary α-amylase, cortisol and IgA concentrations). Collection of blood and saliva samples was repeated immediately post-race. Data regarding race performance was collected within one week after completion of the race.

Includes abstract. / Includes bibliographical references. / Distance running has become increasingly popular in recreational runners. The gastrocnemius is the main muscle used for propulsion in running, and may be at risk for injury due to its morphology. In previous studies, changes in the morphology and architecture of the gastrocnemius muscle have been evident following training, but it is unclear whether these changes are related to training or youth. Previous studies of runners have shown a decrease in gastrocnemius and soleus flexibility, as well as changes in the fascicle length and pennation angle. Gastrocnemius volume has not been compared in low physical activity and active participants. Physiological cross sectional area, based on volume and fascicle length measurements may also provide valuable information about the muscle’s ability to produce force. Ultrasound may be a useful tool in assessing potential training adaptations in the morphology and architecture of the gastrocnemius muscle. The aim of this cross-sectional descriptive study was to assess the differences in architecture and function of the gastrocnemius in endurance runners compared to low physical activity participants. (a) To assess differences in calf function and flexibility between endurance runners and low physical activity individuals, and between male and female participants; (b) To determine differences in gastrocnemius muscle architecture and composition between endurance runners versus low physical activity individuals, and between males and females; and (c) To determine whether there are any relationships between training factors and the structure and function of the gastrocnemius muscle. Thirty participants between 20 and 45 years old were recruited for this study and allocated to groups based on their level of physical activity. The low physical activity group (n = 14) were not participating in any regular physical activity, while the endurance running group (n = 16) were running a minimum of 40 km.wk-1, and had participated in at least one full marathon (42.2 km) in the previous six months. All participants completed informed consent, a physical activity and training questionnaire, and a Physical Activity Readiness Questionnaire (PAR-Q) at the first session. The first session also included body composition measurements; ultrasound imaging to measure gastrocnemius length, thickness, fascicle length, pennation angle and volume; and familiarisation with all physical tests. Physical tests were conducted in the second session, including gastrocnemius and soleus flexibility, calf raise endurance and vertical jump height to assess the function of the components of the triceps surae. There were no significant differences between low physical activity and running groups for gastrocnemius thickness, fascicle length, pennation angle and gastrocnemius length. Gastrocnemius volume (p = 0.02) and physiological cross sectional area (p = 0.01) were significantly greater in the running group compared to the low physical activity group. There were no significant differences between low physical activity and running groups in flexibility or vertical jump height, although male participants had significantly decreased gastrocnemius muscle flexibility (p = 0.046) and significantly greater vertical jump heights (p = 0.01) than females. Calf raise endurance was significantly greater in the running group than in the low physical activity group (p = 0.03). Endurance running leads to specific adaptations in participants in both structure and function. While ultrasound appears to be a reliable measure for assessing architectural components of the gastrocnemius muscle in both active and inactive populations, further cadaver studies may provide valuable information on muscle architecture.

Includes bibliographical references (leaves 52-61). / With regards to swimming, cycling and running, several studies have investigated the physiological and genetic contribution of performance in athletes, different training programs and athletes' adaptation to these programs. Other studies have investigated levels of pain and relative perception of effort (RPE) and the athlete's ability to recover after endurance races... The aim of this thesis is to review the literture which discusses the background to the questions outlined above (Chapter 2), followed by a study which attempts to answer these questions (Chapter 3). The aim of the study was to establish whether the training methods in preparation for the Ironman were related to subjective pain and perception of effort during the race, and the recovery time after the race. The study was designed to establish whether there were differences in these variables between triathletes who predicted their finishing time accurately compared to those triathletes wo under-or over-predicted their performance.

Includes bibliographical references (leaves 104-110). / The grace and ease with which a dancer entertains an audience is deceptive with respect to the sweat and tears shed to achieve such elegance of movement. Ballet demands great flexibility and strength. This is showcased as a story told through movement, full of emotion and expressed to music. As a physiotherapist on watches a ballet in absolute awe of the stresses the human body has to endure. What adaptations are necessary within the musculoskeletal system to allow such movement? Do these adaptations lead to injury?

The aim of the first experiment of this thesis was to determine whether the ingestion of a concentrated sodium chloride solution (100mEq/1) during exercise would expand the plasma volume when fluid was ingested at approximately half the rate at which it was being lost as sweat. Six male cyclists exercised for 90 minutes in the heat (32 ± 1 °C, 55 ± 5% RH) at 66 ± 1 % of VO₂ₘₐₓ while ingesting either no fluid CNF), water (W), or a saline CS) solution (100mEq/1). In the Wand S trials, subjects drank 400ml of the fluid immediately prior to commencing exercise, and 100ml of fluid every 10 minutes during exercise until 80 minutes. In the S trial sodium chloride was ingested in capsules. One capsule containing 0.585g of sodium chloride was ingested with every 100ml of water. At the end of the 90 minute exercise bout they rested in a sitting position for one hour in cool conditions (22 ± 1 °C and 70 ± 5% RH). After the initial drop in plasma volume due to the onset of exercise. plasma volume decreased progressively during the NF trial and was significantly less than the 10 minute value at 80 and 90 minutes (p<0.0033). At 40, 60, 80 and 90 minutes of exercise, the plasma volume in the NF trial was significantly less than in the W and the S trials (p<0.05). There was no significant difference between the W and the S trials at any time. Further, after the initial drop in plasma volume due to the onset of exercise. plasma volume did not decrease any further in either the W or the S trial. Plasma sodium concentrations in the NF and the S trial were significantly elevated at 40, 60, 80 and 90 minutes (p<0.0033). Plasma sodium concentration in the NF and the S trials were also significantly higher than in the W trial at 80 and 90 minutes of exercise (p<0.05). Since the ingestion of a sodium chloride solution containing 100mEq/1 did not have a beneficial effect on plasma volume and plasma sodium concentration, when fluid ingestion rates were approximately half of the rate of sweat loss, it is concluded the under these conditions, the ingestion of a concentrated sodium chloride beverage has no advantage over the ingestion of water. The aim of the second experiment of this thesis was to determine the effect of varying concentrations of sodium chloride ingestion on fluid balance, when the rate of fluid ingestion matched the sweat rate. Six male cyclists cycled for 4 hours at 55% of VO₂ₘₐₓ in mild conditions (20 ± 1°c and 70 ± 5% RH), while ingesting either a low salt (LS) (4.6 mEq/1), a medium salt (MS) (50 mEq/1) or a high salt (HS) (100 mEq/1) beverage. Each beverage also contained a glucose polymer in an 8% concentration (8g/100ml). The subjects ingested 400ml of beverage immediately prior to commencement of exercise, and 150ml of fluid every 10 minutes during exercise until 220 minutes. Sodium chloride in the MS and HS trials was given to the subjects as supplemental gel capsules so that the drink was palatable. At the end of exercise, subjects recovered in a sitting position for 30 minutes. At the end of the 4 hours of exercise, fluid loss via the urine was significantly greater in the LS and the MS trials than in the HS trial (p<0.05). As a result, the fluid deficits in the LS and the MS trials were significantly greater than the fluid deficit in the HS trial. There was no significant difference between the MS and the LS trials for urinary fluid loss. During the 4 hour exercise bout, plasma sodium concentrations in the LS, the MS and the HS trials were not significantly different from one another, nor were they significantly different from resting values. There was no significant difference in the rectal temperature response to exercise in the three trials. It can therefore be concluded that in conditions where fluid ingestion matches sweat rate, attenuation of urinary fluid loss to optimise fluid replacement, relies on the ingestion of sodium chloride in quantities greater than that lost in the sweat. Therefore, for the ingestion of sodium chloride in excess of that which is currently available in sports drinks to beneficial, fluid must be ingested in volumes matching sweat loss.

Several epidemiological reports suggest that athletes engaging in marathon-type running events are at increased risk of symptoms of upper respiratory tract infections (URTI). A possible explanation for this increased susceptibility is that during prolonged, strenuous exercise, production of immunosuppressive oxygen free radicals is increased. The purpose of this study therefore was to examine the effect of anti-oxidant vitamin supplementation on the incidence and severity of post-race symptoms of URTI's among athletes competing in a 90-kilometer ultramarathon footrace. A double blind, randomised, placebo controlled study design was employed. Eighty-five subjects were divided into three experimental and three control groups. Each athlete selected a non-running partner with whom they were paired. This non-running control was of a similar age and was a member of the same household or otherwise closely associated with the runner. The experimental and control groups were divided into those ingesting 250 mg/day of ascorbic acid (n = 13 runners, 11 non-running controls), or 4.5 mg/day of beta-carotene (n = 12 runners, 11 non-running controls) or placebo (n = 19 runners and 19 nonrunning controls). All groups commenced supplementation six weeks before the ultramarathon and continued for two weeks after the race. The runners and non-running controls experienced the same incidence of symptoms of upper respiratory tract infections during the study period (50% and 53% respectively) but significantly more runners than non-running controls experienced severe symptoms of upper respiratory tract infections of infective origin (45% and 18% respectively, p < 0.01). Of the runners, 30. 8% on supplemental ascorbic acid, 41. 7% on beta-carotene and 68% on placebo developed symptoms of URTI's. The comparative figures for non-running controls were 45.5%, 45.5% and 63% respectively. All of the non-running controls (100%) and 80% of the athletes who developed severe symptoms of URTIs were on placebo medication. Al though post-race symptoms of URTI 's are common in distance runners, prolonged, strenuous exercise itself is only one of a number of risk factors for symptoms of URTI. However, ingestion of supplemental anti-oxidant in the form of ascorbic acid or beta-carotene for an eight-week period before and after an endurance running event significantly decreases the severity of athletes' symptoms of upper respiratory tract infections.

Very little data exists on swimmers in South Africa. A series of three studies were undertaken to assess the medical status of young swimmers in the Western Cape, their training habits and how these related to performers. The aim of the first study was to determine the training habits of young competitive swimmers, whether there were gender differences in training, and whether the training habis changed over a three-year period (1995-1998). The second study assessed the prevalence of existing medical conditions in young competitive swimmers and whether there were gender differences amongst the swimmers for the various medical conditions. In the third study, mood changes in young competitive swimmers were monitored over a swimming season to determine whether a relationship exists between mood states and swimming performance.