Diss. (sammanfattning) Stockholm : Karolinska institutet, 2009. / Härtill 5 uppsatser.

The main objective of this Diploma Thesis is to determine effects of endurance running on body weight reduction of men within the age group between 35 and 45 years young middle age. The theoretical part revealed interesting facts and compilations provided by various available resources related to the given issue and thus served as a basis for the elaboration of the practical part consisting in heart rate values obtained during several hours of endurance run. The impact on health of probands (tested men) was discovered while assessing heart rate, BMI values and anthropometric measurements of four skin-fold thickness by using skinfold calipers. The result revealed considerable reduction in body fat percentage rate as a consequence of endurance running which was proved as a convenient and recommended activity bringing many benefits to human health, such as reducing overweight of men within the aforementioned age group.

Title: Effect of asymmetric load on the stereotype of running. Objectives: The aim of this experimental work is to evaluace the electromyographic activity of selected muscles when running without load and with load on the treadmill, and the co- current assessment of the impact of asymmetric load on the lateral weight distribution. Methods: Six recreational runners underwent the experiment during which we monitored electrical activity of m. deltoideus pars anterior, m. trapezius pars ascendes et descendens, lumbar paraspinal muscles, m. gastrocnemius lateralis and m. tibialis anterior while running without load and with load on the periphery of the upper right extremity. For the experiment a motor treadmill at a constant speed of 10 km/h was used and a 0,5 l PET bottle completely filled with water was applied as the load. Changes of lateral weight distribution were assessed having investigated stance on two scales. The measured values were statistically evaluated. Results: Within the group of all the probands it was proved that there existed an impact on normalized average amplitude of EMG signal at left-oriented m. gastrocnemius lateralis. The hypothesis of the influence of asymmetric load on the lateral weight distribution was not demonstrated. Keywords: endurance running, surface...

No description available.

<p> Exercise intensity is one of the major factors determining the utilization of carbohydrates (CHO) and lipids in mammalian skeletal muscle. Using indirect calorimetry, we determined maximal oxygen uptake (VO2max) and whole-body rates of CHO and lipid oxidation in rats selectively bred for high and low running capacity (HCR's and LCR's) during exercise at 50, 60, 70 and 80%VO2max. Previous studies have revealed a pattern of selection where mammals with different aerobic capacities use the same proportions of lipids and CHO when exercising at the same relative exercise intensity and as intensity increases, CHO use increases and lipid use decreases. The present results showed that the HCR's had a VO2max and distance run to exhaustion that was 1.3 and 4.0 times greater than the LCR's respectively. Also, both groups of rats followed the pattern of fuel selection seen in previous studies where the same proportions (in%) of lipids and CHO are used at the same relative exercise intensity. On an absolute scale, the HCR's used more lipids and CHO than the LCR's at all exercise intensities but the results were not always statistically significant. We also determined the exercise intensity that elicited the greatest lipid use to be 60% VO2max in both groups.</p> <p> In order to explain these patterns of fuel selection, metabolic indicators, metabolites and enzymes, in skeletal muscle were measured at rest and post exercise for one hour at 60%VO2max. Specifically, ATP and phosphocreatine (PCr) metabolite concentrations were determined in the medial and lateral gastrocnemius, extensor digitorum longus (EDL), tibialis anterior (TA), and soleus muscle. The medial gastrocnemius and soleus were analyzed (pre and post exercise samples were combined) for their oxidative and glycolytic enzyme activity by measuring citrate synthase (CS), cytochrome oxidase (COX), β-hydroxyacyl CoA dehydrogenase (HOAD), and lactate dehydrogenase (LDH) . PCr and ATP concentrations did not change pre and post exercise and between the HCR's and LCR's except for the EDL where there was a significant decrease (P<0.05) in both metabolites after exercise in both groups of rats. For the enzyme measurements, CS and COX activities were higher (P<0.05) in the HCR's for the soleus and HOAD activities were also higher in the HCR's medial gastrocnemius compared to the LCR's. We concluded that the HCR's have a greater oxidative capacity as shown by their greater aerobic and endurance capacity (VO2max and distance to exhaustion), their ability to oxidize a greater absolute amount of lipids and CHO's at the same relative exercise intensity, and their higher activities of oxidative enzymes in the soleus (CS and COX) and medial gastrocnemius (HOAD). Future research into the mechanisms involved in explaining these patterns of fuel selection may include examining fatty acid transport proteins, fatty acid and CHO availability, fiber types, and catecholamines.</p> / Thesis / Master of Science (MSc)

It is well established that improved nutritional strategies can enhance both health and exercise performance. Scientific developments in recent years have furthered our understanding of cellular metabolism, which in turn, has provided an additional platform to investigate the impact of diet on health and adaptation. The overall aim of this research programme was to build on the current understanding of dietary intake in athletes and the impact dietary manipulation has on cellular and metabolic adaptation at rest and in combination with endurance training. It is postulated that nutrition is the most controllable risk factor impacting long-term health and chronic disease (World-Health-Organization, 2003), and enhanced knowledge of nutrition has been associated with improved dietary choices. A number of nutrition knowledge questionnaires have been developed to assess this; however the validity of each tool is reduced if implemented outside the target population. A valid and reliable general and sport nutrition knowledge questionnaire had not yet been developed. Using a parallel groups repeated measures study design (N = 101) the aim of the first experimental Chapter (Chapter 4) was to develop a new tool to measure general and sport nutrition knowledge in UK track and field athletes. Following the questionnaire design 53 nutrition educated and 48 non-nutrition educated participants completed the questionnaire on two occasions separated by three weeks. The results of the process demonstrated face and construct validity from the development of the question pool, content validity (the nutrition educated group scored > 30% higher that the non-nutrition educated group), reliability (test - retest correlation of 0.98, p < 0.05) and internal consistency (Chronbach's alpha value > 0.7) as such establishing a new tool (Nutrition knowledge Questionnaire for Athletes (NKQA)) for the assessment of general and sport nutrition knowledge in track and field athletes. Athletes' diets are commonly reported as inadequate and previous work has demonstrated a weak positive relationship between diet quality and nutrition knowledge. Additionally a commercially available tool, the metabolic typing questionnaire, claims to identify individual metabolic function and subsequently prescribe a personalised diet to optimise health. Thus the aim of the second experimental Chapter (Chapter 5) was to quantify nutrition knowledge (using the questionnaire developed in Chapter 4), measure diet intake and quality and investigate the efficacy of the metabolic typing questionnaire in UK track and field athletes. Using a parallel groups repeated measures design participants (UK track and field athletes n = 59, and non-athletic control group n = 29) completed a food diary, the NKQA and the metabolic typing questionnaire at two time points through the year (October and April) to investigate seasonal change. The results of the metabolic typing questionnaire concluded that 94.3% of the participants were the same dietary type and would subsequently have been prescribed the same diet. Athletes possess greater general and sport nutrition knowledge the non-athletes (60.4 ± 2.0 % vs. 48.6 ± 1.5 %) and also had better diet quality (76.8 ± 10.5 % vs. 67.6 ± 2.6 %). However no relationship was observed between individual nutrition knowledge score and diet quality (r2 = 0.003, p = 0.63). No difference in dietary intake was observed between power and endurance athletes; average diet intake consisted of 57.0% carbohydrate, 17.1% protein and 25.9% fat. The metabolic typing diet is based around three different diets: high carbohydrate, high protein and mixed diet. The results from Chapter 5 identified that the metabolic typing questionnaire was not able to differentiate between metabolic function in healthy individuals. Additionally all athletes, independent of event (power vs. endurance), consumed similar diets. With such similarities a clearer understanding of the impact such diets have at a cellular level is required. Therefore for the remainder of the thesis it was decided to investigate the impact of dietary manipulation utilising more robust measures. Mitochondria are responsible for energy production; their quantity and density have been associated with improved health and endurance performance. External stressors such as energy reduction, carbohydrate restriction and exercise are potent stimulators of transcription markers of mitochondrial biogenesis. Thus manipulating carbohydrate and energy availability in vivo may enhance cellular adaptation and limited literature exists on the impact increased protein intake has on this. The aim of Chapter 6 was to investigate the impact of acute (7-day) continuous dietary manipulation on metabolic markers, body composition and resting metabolic rate (RMR). Using a repeated measures parallel group (N = 45) design, participants were randomly assigned one of four diets: high protein hypocaloric, high carbohydrate hypocaloric, high protein eucaloric or high carbohydrate eucaloric. The macronutrient ratio of the high protein diets was 40% protein, 30 % carbohydrate and 30% fat, the high carbohydrate diets were 10% protein, 60% carbohydrate and 30% fat. Energy intake in the hypocaloric diets was matched to resting metabolic rate (RMR). Participants consumed habitual diet for 7-days then baseline measures were collected (skeletal muscle biopsy, dual energy X-ray absorptiometry scan (DXA) and RMR, habitual diet was consumed for a further 7-days and repeat testing was completed (these time points were used as a control), the intervention diet was then consumed for 7-days and post measures were collected. The results of the skeletal muscle biopsy demonstrated no group x time interaction in any marker, however a pre-post time difference subsequent to the high protein hypocaloric diet (the diet which induced the greatest metabolic stress) was observed in four transcriptional markers of mitochondrial biogenesis (pre-post intervention fold increase: PCG1-α 1.27, AMPK 2.09, SIRT1 1.5, SIRT3 1.19, p < 0.05). The results of the DXA scan demonstrated that the high protein hypocaloric group lost significantly more fat mass than the high carbohydrate eucaloric group (-0.99 kg vs. -0.50 kg, p < 0.015). Irrespective of macronutrient ratio, no energy-matched between group difference was observed in lean mass (LM) loss. However when matched for macronutrient ratio the high protein diet attenuated LM loss to a greater extent that the high carbohydrate diet, suggesting an important role of increased protein intake in the maintenance of lean mass. No time point or group difference in RMR was observed. This data suggests that a high protein low carbohydrate hypocaloric diet may provide a stimulus to promote skeletal muscle metabolic adaptation. The aim of the final experimental Chapter (Chapter 7) in this thesis was to explore the impact exercise in combination with a high protein diet on metabolic adaptation, substrate utilisation and exercise performance in well trained runners. Using a parallel groups repeated measures study design the participants (well-trained endurance runners, N = 16) consumed normal habitual diet for 7-days, then 7-days intervention diet (high protein eucaloric or high carbohydrate eucaloric, same dietary ratios as Chapter 6) and finally returned to habitual diet for 7-days, training was consistent throughout. A pre exercise muscle biopsy was taken subsequent to each diet and immediately followed by a 10 km sub-maximal run and a time to exhaustion run (TTE) at 95% of velocity at maximal aerobic capacity (vV̇O2max). Post intervention the high protein group presented significant changes in sub-maximal substrate utilisation with 101% increase in fat oxidation (0.59 g·min-1, p = 0.0001). No changes were observed in substrate utilisation in the high carbohydrate group. A trend towards a reduction in average weekly running speed was observed in the PRO group (-0.9 km·h-1), the high carbohydrate group maintained the same training speed. TTE was decreased (-23.3%, p = 0.0003) in the high protein group subsequent to the intervention, no change was observed in subsequent to the high carbohydrate diet. / The high carbohydrate group demonstrated preferential increases in markers of metabolic adaptations (fold increase: AMPK = 1.44 and PPAR = 1.32, p < 0.05) suggesting that training intensity, rather than carbohydrate restriction, may be a more profound driver of metabolic adaptation. All performance measures, in both groups, returned to pre intervention levels once habitual diet was returned; however the increased gene expression observed in the high carbohydrate group remained elevated 7-days post intervention. The increased metabolic stress imposed by reducing carbohydrate intake did not increase transcriptional markers of mitochondrial biogenesis. For continuous endurance training and high intensity endurance performance a high carbohydrate diet is preferential to a high protein diet.

Fossils belonging to the genus Homo, dating as far back as two million years ago, exhibit uniquely efficient features suggesting that early humans had evolved to become exceptional endurance runners. Although they did not have the cushion or stability-control features provided in our modern day running shoes, our early human ancestors experienced far less of the running-related injuries we experience today. The injury rate has been estimated as high as 90% annually for Americans training for a marathon and as high as 79% annually for all American endurance runners. There is an injury epidemic in conventionally shod populations that does not exist in the habitually unshod or minimally shod populations around the world. This has led many to conclude that the recent advent of highly technological shoes might be the problem. Although current literature has been inconclusive, there are two main limitations in virtually all of the studies: 1) transition phases of less than three months and 2) transition phases without rehabilitation exercises. These two aspects are key to the treatment of the structural consequences on the muscles and tendons of the foot and calf that habitually shod individuals have faced. This study includes a discussion of the cumulative consequences that lifelong shoe usage has on the development of the feet and lower legs. I propose a 78-week study that addresses the limitations of past studies by implementing a gradual, 32-week, multi-shoe transition complemented by an evidence-based rehabilitation program. I believe that this approach will restore strength and elasticity to muscles and tendons that have been inhibited by lifelong usage of overconstructed shoes and adequately prepare runners for the increased demand brought on by a­­­­­ changing running mechanic. This comprehensive, multifaceted transition plan to a fully minimalist shoe will provide novel insight into the ongoing barefoot debate. Can this approach finally demonstrate the proposed benefits of losing the shoes?