Browsing by Subject "Running"

Now showing 1 - 6 of 6
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    Exercise and the heart : effects of exercise training on coronary artery disease and on myocardial function, metabolism and vulnerability to ventricular fibrillation
    (1981) Noakes, Timothy D; Opie, Lionel H
    There is epidemiological and experimental evidence suggesting that exercise training may reduce the mortality rate from coronary heart disease, in particular the sudden death rate, and that it may improve the peak functional capacity of the heart. This thesis includes experimental work that is relevant to both these questions.
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    Fuel kinetics during intense running and cycling when fed carbohydrate
    (1996) Derman, Kevin Dale; Hawley, John
    On two occasions six competitive, male triathletes performed in random order, two experimental trials consisting of either a timed ride to exhaustion on a cycle-ergometer or a run to exhaustion on a motor-driven treadmill at 80% of their respective peak cycling and peak running oxygen uptakes (VO₂peak)- At the start of exercise, subjects drank 250 ml of a 15 g.100 ml⁻¹ w.v⁻¹ glucose solution with U-¹⁴C glucose added as tracer and, thereafter, 150 ml of the same solution every 15 min. Despite identical metabolic rates (VO₂ 3.51 ±0.06 vs. 3.51 ±0.10 l.min⁻¹; values are mean± SEM for the cycling and running trials, respectively), exercise times to exhaustion were significantly longer during cycling than running (96 ±14 vs. 63 ±11 min; P<0.05). The superior cycling than running endurance was not associated with any differences in either the rate of blood glucose oxidation (3.8 ±0.1 vs. 3.9 ±0.4 mmol.min⁻¹ ), nor the rate of ingested glucose oxidation (2.0 ± 0.1 vs. 1.7 ±0.2 mmol.min⁻¹) at the last common time point (40 min) before exhaustion, despite higher blood glucose concentrations at exhaustion during running than cycling (7.0 ±0.9 vs. 5.8 ±0.5 mmol.l⁻¹; P<0.05). However, the final rate of total CHO oxidation was significantly greater during cycling than running (24.0 ±0.8 vs. 21.7 ±1.4 mmol C6 .min⁻¹;P<0.01). At exhaustion, the estimated contribution to energy production from muscle glycogen had declined to similar extents in both cycling and running (68 ±3 vs. 65 ± 5%). These differences between the rates of total CHO oxidation and blood glucose oxidation suggested that the direct and/or indirect (via lactate) oxidation of muscle glycogen was greater in cycling than running.
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    A longitudinal study of hormonal and semen profiles in a marathon runners
    (1993) Jensen, Carl Edward; van der Spuy, Zephne Margaret
    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.
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    Stimulating injury-preventive behaviour in sports: the systematic development of two interventions
    (2019-10-21) Kemler, E.; Valkenberg, H.; Gouttebarge, V.
    Abstract Background In addition to the beneficial health effects of being active, sports are also associated with a risk of sustaining injuries. To avoid the occurrence of sports injuries, preventive measures can be applied. The aim of the current article is to provide insight into the systematic developmental process of two evidence-based interventions designed to stimulate injury-preventive behaviour in runners and skiers, in which Intervention Mapping (IM) and Knowledge Transfer Scheme (KTS) are used as developmental protocols. However, the ultimate steps in the process are adjusted to meet requirements of the intervention and the target group. Methods Using a three-step process, we developed two interventions to stimulate injury-preventive behaviour in runners and skiers. Sports participants, sports experts and behaviour experts contributed throughout steps two and three of the developmental process. Results In step one we started with a problem statement in which we used information about the number and the burden of running-related and skiing-related injuries in the Netherlands. In step two, in-depth research was performed using four research strategies. During this step we tried to answer the following question: Which preventive measures or actions should be executed to prevent what injuries by whom, and how should we do that? A desk research/systematic review of the literature, expert meetings, target user surveys, and target user focus group meetings were conducted. In step three of product development, both interventions were developed. During the developmental process, co-creation sessions with target users were held. Before finalizing the interventions, pre-tests of the interventions were performed with target users. Conclusions Through a three-step approach, we developed two interventions to stimulate injury-preventive behaviour in runners and skiers. To develop an intervention that fits the needs of the target population, and will be used by them, it is necessary to involve this population as soon and as much as possible. Several steps in the IM and KTS protocols have thus been adjusted in order to establish an optimal fit between intervention and target group.
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    The effect of "fusafungine" on the incidence of upper respiratory tract symptoms in ultradistance runners
    (1998) Kiessig, Michael; Kiessig, Michael; Schwellnus, Martin P
    Fusafungine is an antibiotic of fungal origin with a potent local anti-inflammatory action (German-Fattal, 1995; German-Fattal, 1996). It is administered locally to the nasal and pharyngeal mucosa by spray. It can be hypothesised that the anti-inflammatory action of fusafungine may decrease the development of mucosa! inflammation in such a manner that the incidence of symptoms of upper respiratory tract infection may be reduced if it is administered before, during and after completion of an ultramarathon. Furthermore, fusafungine could also reduce the risk of secondary bacterial infection. The potential value of fusafungine in reducing the symptoms of upper respiratory tract infections or the development of bacterial upper respiratory infection is the focus of this thesis.
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    The effect of carbohydrate ingestion on performance during a simulated soccer match
    (2013) Goedecke, Julia; White, Nicholas; Chicktay, Waheed; Mahomed, Hafsa; Durandt, Justin; Lambert, Michael
    Aim: This study investigated how performance was affected after soccer players, in a postprandial state, ingested a 7% carbohydrate (CHO) solution compared to a placebo (0% CHO) during a simulated soccer match. Methods: Using a double-blind placebo-controlled design, 22 trained male league soccer players (age: 24 ± 7 years, wt: 73.4 ± 12.0 kg, VO2max: 51.8 ± 4.3 mL O2/kg/min) completed two trials, separated by 7 days, during which they ingested, in random order, 700 mL of either a 7% CHO or placebo drink during a simulated soccer match. Ratings of perceived exertion (RPE), agility, timed and run to fatigue were measured during the trials. Results: Change in agility times was not altered by CHO vs. placebo ingestion (0.57 ± 1.48 vs. 0.66 ± 1.00, p = 0.81). Timed runs to fatigue were 381 ± 267 s vs. 294 ± 159 s for the CHO and placebo drinks, respectively (p = 0.11). Body mass modified the relationship between time to fatigue and drink ingestion (p = 0.02 for drink × body mass), such that lower body mass was associated with increased time to fatigue when the players ingested CHO, but not placebo. RPE values for the final stage of the simulated soccer match were 8.5 ± 1.7 and 8.6 ± 1.5 for the CHO and placebo drinks respectively (p = 0.87). Conclusions: The group data showed that the 7% CHO solution (49 g CHO) did not significantly improve performance during a simulated soccer match in league soccer players who had normal pre-match nutrition. However, when adjusting for body mass, increasing CHO intake was associated with improved time to fatigue during the simulated soccer match.