Calcium channel blockers (CCB) was studied extensively in cardiology for their tissue protective effect following myocardial infarction; we hypothesized that administration of a CCB would interfere with the processes that result in exercise-induced muscle damage (EIMD) and delayed onset muscle soreness. To investigate the effects of a CCB on a development and recovery from EIMD, we used a double blind, placebo controlled protocol to administer CARDIZEM CD, 240 mg/day, for 6 days to 30 college age males and females. To induce EIMD, subjects performed 4 sets of 10 repetitions of squat, leg press, leg extension, and leg curl. We observed no treatment related difference in CPK or DOMS levels. Overall, peak quadriceps force (PQF) were not different between the Placebo and Diltiazem groups, but PQF was significantly greater in the Diltiazem groups immediately after the weight lifting bout. Average quadriceps force (AQF) values decreased in both groups following the exercise bout; however, no difference existed between the groups (p>.05). The Diltiazem group PQF and AQF values returned to the pre-exercise levels 24 hours earlier than did the Placebo group. Neutrophils decreased by 21% in the Diltiazem group compare with a 1.4% increase in the Placebo group, due to large variability in the neutrophil count at the baseline, this difference was not significant. Lymphocytes were not affected by CCB treatment. Administration of diltiazem did not interfere with the development of EIMD as measured by CPK release and the DOMS scores. Diltiazem appeared to affect quadriceps force generation immediately following the weight lifting bout and to speed the recovery of muscle force to pre-exercise level in our sample of college age adults. Heart rate was significantly lower in the Diltiazem group after the administration. There was no difference in either systolic or diastolic blood pressure after the administration between the Diltiazem and Placebo groups. The incidence of side effects was very low and similar in both groups. The administration of this dose and preparation of diltiazem does not change heart rate or blood pressure in a clinically significant fashion, and was well tolerated in our sample of college age adults. / Graduation date: 1997

published_or_final_version / abstract / toc / Physiology / Doctoral / Doctor of Philosophy

The objective of this study was to determine the effect of multiple ice treatments on the signs and symptoms of exercise induced muscle damage. Twenty-four women performed vigorous eccentric exercise of elbow flexors to induce muscle damage. Subjects were randomly assigned into one of three groups(control, experimental group 1, experimental group 2). Experimental groups 1 and 2 received two and six ice bag treatments respectively for two consecutive days post exercise-induced muscle damage. Dependent variables included pain perception, resting arm angle, bicep, forearm, and wrist circumferences, elbow range of motion, and plasma concentrations of creatine kinase. Baseline measurements were obtained on day one and were repeated every 24 hours post-exercise for five days. No significant differences were observed between groups. The results of this study indicate that ice bag treatments do not have any affect on signs/symptoms of exercise-induced muscle damage. / School of Physical Education

Mammalian skeletal muscle can regenerate after injury and this response is primarily mediated by the satellite cell, a muscle stem cell. Following injury, satellite cells are activated to myoblasts, undergo rapid proliferation, migrate towards the injury site, and subsequently differentiate into myotubes in order to facilitate functional muscle repair. Fibrosis, caused by the secretion of structural extracellular matrix (ECM) proteins such as collagen I and fibronectin, by fibroblasts, impairs complete functional repair of the muscle. In this study, the role of the microenvironment during wound conditions was assessed by analysing the effect of specific extracellular matrix and growth factors on myoblast migration. The role of the Rho/ROCK pathway as a possible mechanism in mediating the effects seen was investigated. In order to analyse wound repair in an in vitro setting, we optimised and improved a wound healing model specifically designed for skeletal muscle repair. To this end we also developed a co-culture assay using primary myoblasts and fibroblasts isolated from the same animal. The studies showed that collagen I and fibronectin both increased myoblast migration in a dose-dependent manner. Decorin displayed opposing effects on cellular movement, significantly increasing collagen I-stimulated, but not fibronectin-stimulated, migration of myoblasts. ROCK inhibitor studies revealed a significant increase in migration on uncoated plates following inhibition with Y-27632 compared to untreated control. When cells were cultured on ECM components (Matrigel, collagen I, or fibronectin), the inhibitory effect of Y-27632 on migration was reduced. Analysis of ROCK and vinculin expression, and localization at the leading front, showed that ROCK inhibition resulted in loosely packed focal adhesion complexes (matrix dependent). A reduced adhesion to the ECM could explain the increased migration rates observed upon inhibition with Y-27632. We also investigated the role of TGF-β and decorin during wound repair, as TGF-β is a known pro-fibrotic agent. TGF-β treatment decreased wound closure rates; however, the addition of decorin with TGF-β significantly increased wound closure. The addition of ECM components, Matrigel and collagen I enhanced the effect seen in response to TGF-β and decorin; however, fibronectin negated this effect, with no increase in migration seen compared to the controls. In conclusion, the importance of extracellular matrix components in regulating myoblast migration and therefore skeletal muscle wound repair was demonstrated. We emphasize that, in order to gain a better understanding of skeletal muscle wound repair, the combination of ECM and growth factors released during wounding need to be utilised in assays which mimic the in vivo environment more closely. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

Graduation date: 2006 / We hypothesized that calpain activity is elevated in response to muscle damage. To test this hypothesis, we examined the degradation of α-fodrin into its 150 and 145 kDa fragments following either 20 eccentric or isometric contractions. In addition, experiments were performed in the presence or absence of E-64-d, a calpain inhibitor. Both EDL and SOL muscles displayed significant differences (p<0.003 and p<0.002 respectively) between the raw and normalized 150 and 145 kDa α-fodrin fragments of the DMSO + E-64-d compared to the other bath treatments. Based on our model of exercise-induced muscle damage, we expected to see greater levels of 150 and 145 kDa α-fodrin fragments in those muscles that performed the eccentric protocol. However, there was no evidence that eccentric muscle damage increased the levels of 150 and 145 kDa α-fodrin fragments over the levels observed in the isometric trials. These findings suggest that the magnitude of damage was insufficient to activate calpains.

The purpose of this study was to determine the effects of high intensity eccentric muscle damage on plasma creatine kinase and plasma malondialdehyde. Twelve subjects, who served as their own control, performed 10 sets of eccentric knee extensions at a 10 RM intensity with their dominant leg. The subjects lowered the resistance in slow controlled manner to a three count of a metronome set at one beat per second. The resistance was set at an intensity equal to 120% of the subject's concentric 1RM. Creatine kinase and malondialdehyde were measured pre-exercise and at 24, 48, 72, 96 and 120 hours post-exercise. Results (p<_ .05) showed a significant increase in both creatine kinase and malondialdehyde compared to baseline. Creatine kinase showed significant increases through 120 hours post-exercise, and peaked at 96 hours post-exercise. Malondialdehyde showed significant increases through 72 post-exercise and peaked at 24 hours postexercise. It appears that a single bout, of high intensity, eccentric exercise can cause significant increases in creatine kinase and malondialdehyde. / Department of Speech Pathology & Audiology

Satellite cells are quiescent skeletal muscle specific stem cells that are activated in response to injury to aid in muscle repair and regeneration. The interaction of hepatocyte growth factor (HGF) with these cells is crucial for their activation. However, to date, research on the effect of HGF on skeletal muscle satellite cells has yielded conflicting data. Clarity is therefore required as to its effect on downstream myogenic processes. Furthermore, mouse and rat cell lines and primary culture have been widely used for in vitro studies to investigate the effect of HGF on skeletal muscle physiology and disease; very few studies have been carried out in primary cultured human skeletal myoblasts. As a result, we aimed to investigate and compare the effect of HGF (2, 10 and 50 ng/ml) on mouse C2C12 myoblast versus primary culture human skeletal myoblast (HSkM) proliferation, migration and differentiation. Proliferation was assessed via both cell counts and crystal violet assay, while migration was investigated using the scratch assay. Differentiation was determined via analysis of expression patterns of transcription factors implicated in myogenic commitment (i.e. Pax7, MyoD) as well expression of the structural protein Myosin Heavy Chain (MyHC). We demonstrate a dose-dependent effect of HGF on myoblast proliferation whereby an increase in proliferation was detected in response to 2 ng/ml HGF, whilst 10 ng/ml HGF resulted in a reduction in proliferation capacity of both C2C12 and HSkM myoblasts. Interestingly, the reduction in proliferation in response to 10 ng/ml HGF was accompanied by a down-regulation in Pax7 expression during differentiation of both mouse and human myoblasts. HGF also affected myoblast migration and differentiation in a dose-dependent manner that was inversely proportional to proliferation. HGF (10 ng/ml) stimulated an increase in myogenic commitment and terminal differentiation of C2C12 and HSkM myoblasts as reflected by the increased percentage MyoD positive cells, improved fusion and greater MyHC expression. C2C12 myoblast migration was also stimulated at this HGF concentration, but reduced in response to the lower HGF (2 ng/ml) dose. The decrease in proliferation following incubation with 10 ng/ml HGF, allows cells to exit proliferation into either a mode of migration or differentiation. Our data confirms the importance of HGF during myogenesis and highlights the sensitivity of satellite cells to changing HGF concentration. This has implications in the regulation of skeletal muscle wound repair. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.

Background: The musculoskeletal demands placed on the lower limb musculature of fast bowlers over time have not received much attention. In particular, measures of muscle recruitment changes have, to the author’s knowledge, not been considered. Objective: The present study, therefore sought to establish any associations between an eight over, simulated fast bowling spell, and muscle activation patterns, power output, perceptual demands, and changes in performance. This will enable improvements in the development of training programmes. Methods: Players’ were required to attend two sessions in total. The purpose of the initial session was to collect specific demographic, anthropometric and physiological data and injury history information from each player. In addition, this first session allowed for habituation with the treadmill, the jump meter and all other equipment involved in experimentation. The second testing session involved electrode attachment sites being identified on player’s dominant leg. The areas were then shaved, wiped with an alcohol swab and left to dry, to ensure good connectivity. Pre- and post- measures of muscle activity and functional strength of the lower limbs were recorded in the Department of Human Kinetics and Ergonomics. The protocol took place at the Kingswood High Performance Centre, which is in close proximity to the initial testing site. The protocol involved players bowling eight overs (48 balls). During the protocol, accuracy, ball release speed and perceptual measures were recorded at the end of each over. After the protocol, players were driven back to the Human Kinetics and Ergonomics Department where post-testing measures were completed. The dependable variables of interest were muscle activation, functional strength of the lower limbs, ‘local’ ratings of perceived exertion (RPE), body discomfort, accuracy, and ball release speed. Results: For all muscles it was shown that, as the speed increased so did the muscle activity in players’ lower limbs. There were no significant changes in muscle activity preversus post-protocol. There was however, a general trend of decreasing muscle activity post protocol at higher testing speeds. There were significant (p<0.05) decreases in peak power following the simulated eight over bowling spell. ‘Local’ RPE displayed a significant (P<0.05) increase with each additional over and were observed to reach the ‘heavy’ category. The players’ highest discomfort area was in the lower back, with 13 players perceiving discomfort in this region following the eight over spell. The shoulder and chest were another two areas player’s indicated discomfort with eight players selecting the dominant shoulder. Seven players complained of the dominant side pectoral muscle, leading foot and dominant latissimus dorsi muscle being uncomfortable. Interestingly, the dominant pectoral showed the highest body discomfort ratings amongst players. There were no significant changes in accuracy between overs although there were large interindividual differences in accuracy points between players. The decrease in ball release speed observed during over seven was shown to be significantly (p<0.05) lower than overs one to four. Conclusion: The power output and perceived strain results of the players, appears to indicate the presence of fatigue in players. However, the results are not conclusive, as the fatigue was not shown in muscle recruitment patterns, as well as the body discomfort ratings. There was a non-significant trend observed in the lower limb muscle activation decreasing at higher speeds. Players were able to maintain accuracy. However, the significantly lower ball release speed observed during over seven showed players performance decreasing.

Made available in DSpace on 2015-01-26T13:21:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-07-29Bitstream added on 2015-01-26T13:30:39Z : No. of bitstreams: 1 000796053.pdf: 812728 bytes, checksum: 9090f1792085c41d85dc7a1fc46dfddc (MD5) / O futebol é um esporte com característica intermitente pela realização de esforços de alta intensidade e curta duração, interposto por períodos de menor intensidade e duração variável. As atividades dos jogadores durante a temporada competitiva são intensas, podendo promover alterações metabólicas, principalmente no músculo esquelético. As elevadas contrações musculares excêntricas induzem danos e respostas inflamatórias, que podem influenciar a produção de espécies reativas de oxigênio (EROs) durante e depois de esforço no futebol. Além disso, o exercício exaustivo promove danos musculares, que são induzidos principalmente por estresse mecânico resultando em aumento substancial de proteínas intracelulares no plasma. Diversas pesquisas estão sendo realizadas para descobrir se a ingestão de antioxidantes possa prevenir os danos causados pelo exercício exaustivo, melhorando o processo de recuperação do exercício. A quercetina é um composto de flavonoides que tem sido investigada por apresentar benefícios para saúde, além de propriedades ergogênicas. Suas atividades biológicas estão ligadas a capacidade antioxidante e anti-inflamatória. Dentre suas diversas funções, a quercetina parece aumentar a atividade de enzimas antioxidantes naturais como a superóxido dismutase e catalase. Também age inibindo a ação da xantina oxidase, principal fonte de EROs durante exercícios intensos de curta duração, atenuando o estresse oxidativo e resposta inflamatória, principalmente in vitro. Seu efeito no desempenho está relacionado com o aumento do processo de biogênese mitocondrial por meio das vias de sinalização intracelular. Apesar dos resultados controversos na literatura acerca do efeito ergogênico da quercetina, as meta-análises existentes indicam que há pequeno, porém significante benefício no desempenho / The soccer is a sport with intermittent feature for conducting efforts of high intensity and short duration, brought by periods of lower intensity and variable duration. The activities of the players during the competitive season are intense and may promote metabolic changes, particularly in skeletal muscle. The high eccentric muscle contractions induce damage and inflammatory responses, which may influence the production of reactive oxygen species (ROS) during and after an effort in soccer. Furthermore, the exhaustive exercise promotes muscle damage which are mainly driven by mechanical stress resulting in a substantial increase of intracellular proteins in plasma. Several studies are being conducted to find out if the intake of antioxidants may prevent damage caused by exhaustive exercise, improving the process of recovery from exercise. Quercetin is a flavonoid compound which has been investigated for presenting health benefits beyond ergogenic properties. Their biological activities are linked to antioxidant capacity and anti inflammatory. Among its many functions, quercetin appears to increase the activity of natural antioxidant enzymes such as superoxide dismutase and catalase. Also acts by inhibiting the action of xanthine oxidase, the main source of ROS during intense exercise of short duration, attenuating oxidative stress and inflammatory response, especially in vitro. Its effect on performance associated with increased mitochondrial biogenesis process by means of intracellular signaling pathways. Despite the controversial results in the literature about the ergogenic effect of quercetin, existing meta-analyzes indicate that there is a small but significant performance benefit

Made available in DSpace on 2015-01-26T13:21:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-02-27Bitstream added on 2015-01-26T13:30:20Z : No. of bitstreams: 1 000799159_20160101.pdf: 164209 bytes, checksum: d17a175dccefdffeeefbc01eb2655fb2 (MD5) Bitstreams deleted on 2016-01-04T10:26:41Z: 000799159_20160101.pdf,. Added 1 bitstream(s) on 2016-01-04T10:28:33Z : No. of bitstreams: 1 000799159.pdf: 511559 bytes, checksum: 1ea09022789edf1af84755c0bef56cb4 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Introdução: A erva mate (Ilex Paraguariensis) é uma bebida consumida principalmente na América do Sul e contém componentes com função antioxidante e possíveis propriedades ergogênicas. Sabe-se que o exercício eleva o estresse oxidativo e a lesão muscular, portanto o consumo do chá mate poderia proporcionar efeitos benéficos. Objetivo: Avaliar o efeito do consumo agudo de chá mate nos parâmetros de estresse oxidativo e lesão muscular em jogadoras de futebol profissional que foram expostas ao exercício exaustivo. Métodos: Quinze jogadoras de futebol (22,1 ± 4,2 anos) foram avaliadas de forma randomizada consumindo 5g de chá mate solúvel (400 ml) ou 400 ml de água em estudo cruzado com 7 dias de washout. Ambas as bebidas foram fornecidas após jejum noturno e 60 minutos antes de um teste incremental de esteira até a exaustão. Todos os indivíduos ingeriram 30g de maltodextrina 30 minutos antes do início do teste. Por meio do desempenho no teste de esteira do grupo água, foram criados dois subgrupos com os indivíduos com o melhor tempo de esteira (MTE, n=8) e os outros com pior tempo de esteira (PTE, n=7). Amostras sanguíneas foram coletadas em jejum, pré e pós-exercício, sendo avaliados marcadores de lesão muscular (CK, AST and ALT), antioxidante (TAP e ácido úrico), estresse oxidativo (MDA) e anaerobiose (lactato). Foi utilizado ANOVA de medidas repetidas para comparar as variáveis basal, pré e pós exercício; e teste-t dependente para comparar os valores de delta (final-inicial) ( ) e o tempo de esteira entre os grupos chá e água. Resultados: Quando foram avaliados todos os indivíduos, notou-se maior concentração de lactato e redução das concentrações de ALT no grupo chá mate. No grupo PTE , quando houve consumo de chá mate notou-se maior tempo de esteira, lactato e ácido úrico do que o grupo que consumiu água. No grupo MTE não foi observado aumento das concentrações ... / Background: Yerba mate tea (Ilex Paraguariensis) is an herbal tea beverage consumed mainly in South America that presents components with antioxidant, antinflammatory, and possible ergogenic properties. It is known that exercise increases oxidative stress and muscle damage, and then mate tea intake could show beneficial effects. Purpose: To evaluate the effect of acute intake of yerba mate on blood markers of oxidative stress and muscle damage in female soccer players exposed to exhaustive exercise. Methods: 15 female soccer players (22.1 ± 4.2 years old) were studied randomized with either 5g of soluble yerba mate (400 ml) or 400 ml of water cross-overly with 7 days of washout. Both liquids were given after an overnight fasting and before 60 minutes of a treadmill incremental test up to exhaustion. All subjects were fed with 30g of maltodextrin 30 minutes before the beginning of the test. From the treadmill performance of the drinking-water players it was evaluated all the individuals and also was created the sub groups of Higher Run Time (HRT, n=8) and the others (WRT, n=7). Blood samples were collected before and immediately post-exercise and assayed for markers of tissue integrity (enzymes CK, AST and ALT), antioxidants (TAP and uric acid), oxidants (MDA) and anaerobiosis (lactate). It was used repeated-measures ANOVA to compare the variables in basal, pre and post-exercise; and t-test dependent to compare the delta (final-initial) values ( ) and time of treadmill run between groups, for p<0.05. Results: In all the individuals it was noted higher lactate and lower ALT levels after the exercise in mate group. The yerba mate tea group showed longer treadmill run along with higher increase of lactate and uric acid than the water group in the WRT sub group. In HRT it was observed no increase in AST and lower ALT levels in mate tea group. Conclusion: Yerba mate intake by female soccer players increased tolerance to exhaustive exercise ...