A ausência de terapias eficazes para a caquexia permanece como um problema central para o tratamento do câncer no mundo. Em contrapartida, o treinamento de força (i.e. também conhecido como treinamento resistido) tem sido amplamente utilizado como uma estratégia não farmacológica anticatabólica, prevenindo a perda da massa e da função da musculatura esquelética. Entretanto, o papel terapêutico do treinamento de força na caquexia do câncer permanece apenas especulativo. Portanto, nesse estudo avaliamos se o treinamento de força poderia atenuar a perda da massa e da função da musculatura esquelética em um severo modelo de caquexia do câncer em ratos. Para isso, ratos machos da linhagem Wistar foram randomizados em quatro grupos experimentais: 1) ratos sedentários injetados com solução salina na medula óssea (Controle); 2) ratos injetados com solução salina na medula óssea e submetidos ao treinamento de força (Controle + T); 3) ratos sedentários injetados com células do tumor Walker 256 na medula óssea (Tumor); e 4) ratos injetados com células do tumor Walker 256 na medula óssea e submetidos ao treinamento de força (Tumor + T). Foram avaliados a massa e a área de secção transversa da musculatura esquelética, marcadores de disfunção metabólica e do turnover proteico, a função da musculatura esquelética in vivo e ex vivo, o consumo alimentar, o crescimento tumoral e a sobrevida dos grupos experimentais com tumor. O grupo Tumor apresentou atrofia muscular após quinze dias da injeção das células tumorais como pode ser observado pela redução na massa dos músculos Plantaris (- 20,5%) e EDL (-20%). A atrofia no músculo EDL foi confirmada por análises histológicas, demonstrando uma redução de 43,8% na área de secção transversa. Embora o treinamento de força tenha aumentado o conteúdo proteico da lactato desidrogenase e revertido totalmente o conteúdo da forma fosforilada de 4EBP-1 (i.e. repressor da transcrição de mRNA), ele não atuou na morfologia da musculatura esquelética nos animais com tumor. Além disso, o treinamento de força não atenuou a perda de função da musculatura esquelética, a anorexia, o crescimento tumoral ou a taxa de mortalidade. Contudo, a força muscular, avaliada pelo teste de 1RM, apresentou uma correlação negativa com a sobrevida dos animais (p = 0,02), sugerindo que a perda de força prediz a mortalidade nesse modelo experimental de caquexia do câncer. Em suma, a injeção de células do tumor Walker 256 na medula óssea induz caquexia do câncer em ratos. O treinamento de força não foi eficaz em atenuar a perda de massa e função da musculatura esquelética nesse modelo. Entretanto, a força muscular prediz a sobrevida dos animais, sugerindo que novos estudos são necessários para elucidar o possível efeito terapêutico do treinamento de força para atenuar a caquexia do câncer e a progressão tumoral / The lack of therapies for cachexia is a key problem in cancer treatment. In contrast, resistance exercise training (RET) has been adopted as nonpharmacological anti-catabolic strategy, preventing muscle wasting and muscle dysfunction. However, the role of RET to counteract cancer cachexia is still speculative. Presently, we test whether RET would counteract skeletal muscle wasting in a severe cancer cachexia rat model. Methods: Male Wistar rats were randomly assigned into four experimental groups; 1) untrained control rats injected with saline solution in the bone marrow (control), 2) rats injected with saline solution in the bone marrow and submitted to RET (control + RET), 3) untrained rats injected with Walker 256 tumor cells in the bone marrow (tumor) and 4) rats injected with Walker 256 tumor cells in the bone marrow and submitted to RET (tumor + RET). Skeletal muscle mass and fiber cross sectional area, markers of metabolic and protein turnover impairment, in vivo and ex vivo skeletal muscle function, food intake, tumor growth and mortality rate were assessed. Results: Tumor group displayed skeletal muscle atrophy fifteen days post tumor cells injection as assessed by Plantaris (-20.5%) and EDL (-20.0%) muscle mass. EDL atrophy was confirmed by histological analysis, showing 43.8% decline in the fiber cross sectional area. Even though RET increased the lactate dehydrogenase protein content and fully restored phosphorylated form of 4EBP-1 (i.e. a repressor of mRNA translation) to the control levels in skeletal muscle, it failed to rescue muscle morphology in tumorbearing rats. Indeed, RET has not mitigated loss of muscle function, anorexia, tumor growth or mortality rate. However, loss of strength capacity (assessed by 1-RM test performance) demonstrated a negative correlation with rats´ survival (p = 0.02), suggesting that loss of strength capacity predicts cancer mortality. Conclusions: Bone marrow injection of Walker 256 tumor cells in rats induces cancer cachexia. RET is ineffective to mitigate cancer-induced skeletal muscle wasting in this rat model. However, strength capacity predicts cancer survival, suggesting that new studies are needed to elucidate the putative therapeutic role of different exercise training regimens in counteracting cancer cachexia and tumor progression

Introdução. A prática regular do exercício de força (EF) está associada a adaptações metabólicas, neuromusculares e cardiovasculares que repercutem de maneira positiva sobre a saúde e qualidade de vida de seus praticantes. No entanto, Indivíduos sedentários apresentam comprometimentos agudos na função endotelial após EF de alta intensidade. Objetivo. Avaliar a função endotelial de indivíduos sedentários de meia idade em resposta a diferentes intensidades do EF. Métodos. 11 indivíduos sedentários (40,1±3,9 anos; 27,3±1,4 kg/m2) realizaram EF em três condições experimentais: extensão de joelhos a 50% de 1RM (MI), 80% de 1RM (AI) e repouso na condição controle (CON). Foi realizada avaliação da vasodilatação mediada pelo fluxo (FMD) antes, 30 minutos após e 60 minutos após os protocolos. A quantificação das concentrações de NO2 e NO3 (NOx), endotelina-1 (ET-1) e TBARS foram realizadas antes, imediatamente após e 60 minutos após os protocolos. A pressão arterial foi mensurada antes e após os protocolos Resultados. A FMD aumentou significativamente 30 minutos após o exercício na condição MI (12,5± 4,10 para 17,2±3,9 %; p=0,01) bem como os níveis de NOx (6,8± 3,3 vs. 12,6± 4,2μM; p= 0,007). A concentração de ET-1 aumentou imediatamente após na condição AI (20,02±2,2 vs. 25,4± 2,1pg/ml; p= 0,004). A elevação da pressão arterial não diferiu entre as condições MI e AI. As concentrações de TBARS não se alteraram ao longo dos protocolos. Conclusão. O EF de moderada intensidade aumenta a FMD e os níveis NOx após uma sessão aguda de exercício em indivíduos sedentários de meia idade, estes resultados sugerem que menores intensidades do EF são mais seguras ao iniciar um programa de exercícios. / Regular resistance exercise (RE) is associated with metabolic, neuromuscular and cardiovascular adaptation that results in improvement of quality of life and health. However, sedentary subjects have been showing an acute impairment on endothelial function after high intensity resistance exercise. The aim of this study was to evaluate the endothelial function in sedentary middle age men after RE in different intensities. Methods. Eleven middle age sedentary men (40,1±3,9 years; 27,3±1,4 kg/m2) performed RE in three different conditions: knee extension at 50% of one 1RM (MI), at 80% of 1RM (HI) and rest in the control group (CON). Flow mediated dilation (FMD) was assessed before, 30 and 60 minutes of exercise. Venus plasma concentration of ET-1 NOx and TBARS were measured before, immediately after and 60 minutes after exercise. Blood pressure was evaluated before and after exercise. Results. There was a significant improvement in FMD 30 minutes after exercise in the MI condition (12,5± 4,10 vs 17,2±3,9%; p= 0,016; p=0,01). The plasma NOx concentration was significant higher immediately after MI (6,8± 3,3 vs. 12,6± 4,2μM; p= 0,007). There was a significant improvement in the plasma ET-1 concentration immediately after HI (20,02±2,2 vs. 25,4± 2,1pg/ml; p= 0,004). There was no significant difference in the BP between the experimental conditions (MI vs HI) and TBARS throughout the experimental conditions. Conclusions. Resistance exercise performed in moderate intensity improve endothelial function in sedentary middle aged men, there results suggest that lower intensities of RE could be safe for this population in the beginning of the exercise programs.

O protocolo de treinamento de força (TF) 3x15:88s (sériesxrepetições:pausa entre as séries) é usualmente recomendado para hipertensos. Durante a execução dos protocolos de TF a pressão arterial (PA) se eleva expressivamente, o que pode gerar um risco de eventos cardiovasculares indesejados ao hipertenso. A manipulação da densidade de treinamento pode ser uma forma de amenizar esses picos de PA sem alterar o volume ou a intensidade do protocolo de TF. Objetivo: Comparar o efeito agudo da execução de dois protocolos de TF equalizados em densidade sobre as respostas cardiovasculares em hipertensos medicados. Materiais e Métodos: 12 hipertensos essenciais (48±8 anos) executaram dois protocolos de TF equalizados em densidade em dias diferentes e de forma aleatória: A)- 3x15:88s e B)- 9x5:22s com a intensidade de 50%1RM, em dois diferentes exercícios, extensão bilateral de joelhos (EBJ) e flexão unilateral de cotovelo (FUC). Os dois protocolos continham o mesmo número de repetições (45rep) e a mesma duração total de pausa (176s). A PA e frequência cardíaca (FC) foram constantemente monitoradas. Também foi medida a concentração de lactato, a percepção subjetiva de esforço (PSE) e a de recuperação (PSR). Resultados: A ANOVA de dois fatores (protocolo e tempo) revelou maiores deltas de PA sistólica (PAS) no protocolo 3x15:88s tanto no EBJ (+84±39 vs +67±20 mmHg) quanto no FUC (+46±25 vs +37±18 mmHg). Já a PA diastólica (+58±37 vs +39±13 mmHg) também foi maior no protocolo 3x15:88s, mas apenas no EBJ. O protocolo 3x15:88s apresentou maior PSE no EBJ e maior concentração de lactato no FUC. Além disso, os dois protocolos de TF geraram o mesmo estresse cardiovascular médio demonstrado pelo cálculo da área sob a curva de PA a cada batimento cardíaco. Conclusão: O protocolo 9x5:22s foi mais eficaz em reduzir o pico de PA do que o protocolo com característica aos recomendados aos hipertensos. Assim, a aplicação desse protocolo reduz o risco de eventos cardiovasculares indesejados / resistance exercise (RE) protocol composed of 3x15:88s (setsxreps:rest) is usually recommended for hypertensive individuals. During the execution of RE protocols, the blood pressure (BP) rises significantly, which can generate a high risk of cardiovascular events. Manipulation of the work:rest ratio may be a strategy to decrease BP peaks without altering the total work provided by the RE protocol. Objective: To compare the acute effect of two RE protocols equated by work : rest ratio on cardiovascular responses in medicated hypertensive volunteers. Materials and Methods: 12 subjects (48±8 y) performed two RE protocols equated by work:rest ratio on different days and in random order: A)- 3x15:88s and B)- 9x5:22s with the intensity of 50%1RM in two different exercises, bilateral knee extension (BKE) and unilateral elbow flexion (UEF). The two RE protocols contained the same number of reps (45 reps) and the same total rest duration (176s). Blood pressure and heart rate (HR) were continuously monitored. Blood lactate concentration, rate of perceived exertion (RPE) and rate of perceived recovery (RPR) were also measured. Results: The two-way ANOVA (protocol and time) revealed higher systolic BP delta (SBP) in the 3x15:88s protocol in both BKE (+84±39 vs. +67±20 mmHg) and UEF (+46±25 vs. +37±18 mmHg) exercises. The diastolic BP (DBP) was higher in the 3x15:88s protocol only in the BKE (+58±37 vs 39±13 mmHg). In addition, the 3x15:88s protocol showed higher RPE in the BKE and higher lactate concentration in the UEF. Furthermore, the two protocols generate the same mean cardiovascular stress demonstrate by the blood pressure area under the curve. Conclusion: The protocol 9x5:22s was more effective in reducing the peak of BP than a protocol with the characteristics recommended to hypertensive patients (3x15:88s). Thus, the application of this protocol reduces the risk of cardiovascular events

INTRODUÇÃO: O dano muscular induzido pelo exercício (DMIE) em humanos ocorre quando o indivíduo realiza exercícios não-habituais, muito intensos ou de longa duração. Muitos protocolos experimentais têm se dedicado ao estudo do DMIE, porém poucos deles, principalmente aqueles com ações excêntricas, reproduzem uma situação real de treinamento físico. OBJETIVO: O objetivo geral desta pesquisa é verificar e comparar a ocorrência de dano muscular nos flexores do cotovelo induzido pelo sistema de treinamento de cargas descendentes em exercício resistido em duas diferentes intensidades por meio de marcadores indiretos de dano muscular: creatina quinase (CK), mioglobina (Mio), dor e torque muscular. MÉTODO: Foram voluntários 9 indivíduos do gênero masculino com idade média (\'+ OU -\' desvio padrão) de 26,78 \'+ OU -\' 4,32 anos, peso médio 84,02 \'+ OU -\' 13,88 quilos e altura média 181,33 \'+ OU -\' 8,46 centímetros. Os indivíduos realizaram dois protocolos de exercício resistido com ações concêntricas e excêntricas dos flexores do cotovelo nos exercícios rosca Scott e rosca direta com cargas descendentes em diferentes intensidades, uma iniciada em 90% de 1-RM (PROTOCOLO 90%) e outra iniciada em 75% de 1-RM (PROTOCOLO 75%). Os marcadores de dano muscular CK, Mio, dor e torque muscular foram avaliados previamente ao exercício, imediatamente após o exercício, 24, 48, 96 e 168 horas após o exercício. RESULTADOS: O pico de concentração de CK ocorreu 24 horas após a sessão de exercício dos PROTOCOLOS 75% e 90%, sem diferenças significativa entre os valores (p < 0,05). O pico de concentração de Mio ocorreu imediatamente após a sessão de exercício dos PROTOCOLOS 75% e 90%, sem diferenças significativa entre os valores (p < 0,05). O pico de dor ocorreu 24 horas após a sessão de exercício do PROTOCOLO 75% e permaneceu com o mesmo valor 48 horas após, com percepção referente à \"dor um pouco forte\" indicada na escala de Borg e no PROTOCOLO 90% obteve o pico imediatamente após o esforço com percepção referente à \"dor moderada\". A maior diminuição do torque muscular ocorreu imediatamente após a sessão de exercício dos PROTOCOLOS 75% e 90% sem diferenças significativa entre os valores (p < 0,05). CONCLUSÃO: Foi possível sugerir a ocorrência do dano muscular e ambos os protocolos pelas variáveis investigadas. O torque muscular demonstrou ser o melhor marcador do dano muscular por avaliar de forma não-invasiva a funcionalidade e restabelecimento das estruturas do músculo. O PROTOCOLO 90% parece ser mais vantajoso praticamente por demonstrar as mesmas características nas variáveis CK, Mio e torque muscular com menor percepção de dor. Porém, pesquisas com adaptações ao treinamento crônico são necessárias para fortalecer estas afirmações. / INTRODUCTION: Exercise-induced muscle damage (EIMD) in humans occurs after unaccustomed or vigorous exercise. Various experimental models was dedicated to EIMD, however few studies, essential those with eccentric action, replicated action that commonly occur during real physical training. PURPOSE: The general purpose of this research was to verify and to compare changes in indirect markers of muscle damage (Creatine Kinase (CK), myoglobin (Myo), pain and muscle torque) on the elbow flexors following training system of drop set in resistance exercise in two different intensities. METHODS: 9 young men (age: 26,78 \'+ OU -\' 4,32 years, height: 181,33 \'+ OU -\' 8,46 cm, body mass: 84,02 \'+ OU -\' 13,88 Kg) performed two exercise protocols of drop set resistance exercise with actions concentric and eccentric of the elbow flexors in Scott arm curl and direct arm curl of 90% (PROTOCOL 90%) and 75% (PROTOCOL 75%) of one maximal repeated. The indirect markers was obtained before, immediately after, and 24, 48, 96 and 168 hours after exercise. RESULTS: The CK\'s concentration peak occurs 24 hours after exercise in both protocols, without significant differences (p < 0.05). The Myo\'s concentration peak occurs 24 immediately after the exercise in both protocols, without any significant differences (p < 0.05). The pain peak 24 hours after the exercise of PROTOCOL 75% and continued in the same value 48 hours later, with pain perception of \"pain a little strong\", indicated in Borg\'s Scale. In the PROTOCOL 90% obtained a peak immediately after exercise with perception of \"moderate pain\". The greater reduction of the muscle torque occurs immediately after the exercise in both protocols, without any significant difference (p < 0.05). CONCLUSION: It was possible suggest, through of indirect markers, that both protocols induced a muscle damage. The muscle torque shown to be a better marker of muscle damage because is a non-invasive way to evaluate the functionality of muscle structure. The PROTOCOL 90% seem to be more profitable in the practice because of magnitude pain perception.

In this work we have developed three ordinary differential equation models of biological systems: body mass change in response to exercise, immune system response to a general inflammatory stimulus, and the immune system response in atherosclerosis. The purpose of developing such computational tools is to test hypotheses about the underlying biological processes that drive system outcomes as well as possible real medical interventions. Therefore, we focus our analysis on understanding key interactions between model parameters and outcomes to deepen our understanding of these complex processes as a means to developing effective treatments in obesity, sarcopenia, and inflammatory diseases. We develop a model of the dynamics of muscle hypertrophy in response to resistance exercise and have shown that the parameters controlling response vary between male and female group means in an elderly population. We further explore this individual variability by fitting to data from a clinical obesity study. We then apply logistic regression and classification tree methods to the analysis of between- and within-group differences in underlying physiology that lead to different long-term body composition outcomes following a diet or exercise program. Finally, we explore dieting strategies using optimal control methods. Next, we extend an existing model of inflammation to include different macrophage phenotypes. Complications with this phenotype switch can result in the accumulation of too many of either type and lead to chronic wounds or disease. With this model we are able to reproduce the expected timing of sequential influx of immune cells and mediators in a general inflammatory setting. We then calibrate this base model for the sequential response of immune cells with peritoneal cavity data from mice. Next, we develop a model for plaque formation in atherosclerosis by adapting the current inflammation model to capture the progression of macrophages to inflammatory foam cells in response to cholesterol consumption. The purpose of this work is ultimately to explore points of intervention that can lead to homeostasis.

Highly-active antiretroviral therapy (HAART) has improved the prognosis of HIV-infected individuals. Unfortunately it has also been associated with impaired functional capacity and development of metabolic perturbations which increases health risk. This study tested the hypothesis that a combined cardiorespiratory and resistance exercise training (CARET) intervention may result in significant health benefits in HIV-infected individuals receiving HAART. Thirty-seven HIV-infected men and women, predominantly of lower socioeconomic status (SES), were recruited and randomly assigned to: 1) a group of moderate-intensity CARET for three months or 2) a control group receiving no exercise intervention for three months. At baseline and following the intervention, physical characteristics (body weight, body mass index, waist circumference, and blood pressure), physical fitness variables (estimated VO2max and one repetition maximum for upper and lower body), metabolic variables (fasting glucose and serum lipids), immune functioning (CD4+ T Cell count, CD4/CD8 ratio, and HIV RNA viral load), and quality of life (SF-36 Health Survey) were measured. Exercise participants evidenced increases in estimated VO2max (21%, p < 0.01), upper body strength (15%, p < 0.05), and lower body strength (22%, p < 0.05), while showing reductions in waist circumference (-2%, p < 0.05), and fasting glucose (-16%, p < 0.05). While the control group showed a significant decrease in CD4+ T cell count (-16%, p < 0.05) from baseline, the exercise group maintained a more stable count following training (-3%, p = 0.39). Finally, the exercise participants showed self-reported improvements in physical (11%, p < 0.03) and mental (10%, p < 0.02) quality of life. In conclusion, our study demonstrated that a three-month supervised and moderate intensity CARET program performed three times a week, can result in significant improvements in physical characteristics, physical fitness, metabolic variables, and physical and mental quality of life. Furthermore, the same intervention resulted in more favorable immunological responses following training in HIV-infected individuals of lower SES. Key words: Highly active antiretroviral therapy, HIV, combined aerobic and resistance exercise training, cardiorespiratory fitness, muscular strength, and immune functioning.

Previous research has shown that chronic exercise positively impacts body image in women. Research defining the modality that yields the best results following an acute session of exercise has yet to be determined. This research attempted to show the psychological benefits that exercise could have on female body image after only one bout of exercise. PURPOSE: The purpose of the current study was to examine the effects of three different modalities of acute exercise on state body image in women. This study aimed to determine which modality, if any, is more effective in increasing state body image. METHODS: Twenty-five female participants (20.2 ± 2.2 years; 23.6 ± 4.0 BMI, 25.5 ± 6.0 body fat percent) attended laboratory sessions on six different occasions; the initial informed consent, risk stratification, and descriptive data session, the familiarization session, the three exercise sessions, and the control session. During the familiarization session, each participant was acquainted with each exercise modality. The aerobic (AE) session consisted of a five-minute warm-up, 30 minutes of treadmill exercise, and a five-minute cool-down. The interval circuit (IC) session involved a five-minute warm-up, two circuits containing five bodyweight exercises each, and five minutes of cool-down stretching. The resistance (RE) session included a five-minute warm-up, three sets of eight repetitions of the bench press, bent-over row, overhead press, squat, deadlift, and lunge exercises, and five-minutes of cool-down stretching. The control session included 40 minutes of quiet reading. Ratings of perceived exertion and heart rate were monitored and recorded during each trial. State body image, positive mood, and negative mood were measured immediately before and after each experimental session. RESULTS: Following the AE and RE sessions, state body image significantly improved from pre- to post-session (AE: 5.2 ± 1.2 to 5.7 ± 1.0; RE: 5.4 ± 1.4 to 5.9 ± 1.2; p < 0.05). Only the RE post-session state body image (5.4 ± 1.4) was significantly different from the CO post-session state body image (5.4 ± 1.1; p < 0.05). The AE and RE sessions significantly increased positive mood and decreased negative mood from pre- to post-session (p < 0.05). CONCLUSION: Participation in the aerobic and resistance sessions significantly improved body image from pre- to post-exercise. Resistance exercise was the only research modality that yielded significantly higher post-exercise state body image as compared to the control session. Thus, a single resistance exercise session may help individuals to improve their state body image.

The thesis aimed to analyse the acute neuromuscular (NM) response during and following maximum strength and power training methods. The primary aim of study one was to establish the reliability of biomechanical and surface electromyographic (sEMG) measurements during barbell squat exercise. This would enable the subsequent studies to precisely assess muscle activity and mechanical power during barbell resistance exercise sessions. Nine male well-trained subjects performed squat exercise on three separate trial days. Each trial comprised one set of squat at 50, 75 and 100% of 3RM load. Synchronous recordings of knee joint kinematics from a flexible electrogoniometer, barbell displacement from a single linear position transducer and quadriceps sEMG amplitude were made. The mean maximum knee angle during squat was recorded at each load, and the overall inter-trial coefficient of variation (CV) was 5.5%. Mean concentric repetition power was processed from displacement data and derived into force and velocity values. The overall inter-trial CV for mean power was found to be 8.4%. The raw sEMG signal was processed into root mean square (RMS) amplitude and normalised to values taken from pre-trial knee extension maximum voluntary contractions (MVC). RMS amplitude was processed for the whole concentric phase and a 200 ms time interval at a knee angle of 70°, which matched the knee angle used during MVC. Inter-trial CV for RMS amplitude from the concentric phase and 70° knee angle were 7.2% and 16.4% respectively. There were no differences in RMS amplitude, maximum knee angle or mean power across trial days. It was concluded there was acceptable reliability for all three measurements (CV < 10%), if RMS amplitude was processed from the concentric phase. Based upon the measurement reliability, the analysis system was considered suitable for monitoring power and sEMG during barbell exercise. The second study aimed to establish the reliability of muscle fibre conduction velocity (MFCV) measurements during barbell squat. This was of interest, as MFCV may provide useful information of NM recruitment and fatigue processes during resistance exercise. The study was also used as a preliminary investigation of MFCV response, in comparison to RMS amplitude, to increasing fatigue and load during squat exercise. Nine well-trained male subjects performed a series of exercises on two separate trial days. Each trial comprised isometric knee extensions at 50, 75 and 100% of MVC force, followed by barbell squats at 50, 75 and 100% of 3RM, and then a maximal bout of squat jumps at 50% 3RM load, performed until failure. sEMG measurements were recorded from a four-electrode array, secured upon the vastus lateralis. Normalised RMS amplitude was processed as above, and MFCV was processed from the inter-electrode distance and time delay between two double differentiated and correlated signals, using bespoke software. The overall value of MFCV during squat was 5.8 m.s-1. The inter-trial CV for MFCV was 9.6% during squat and 12.1% during squat jump. Based upon acceptable reliability of 10%, MFCV measurements from barbell squats were considered reliable. As expected, MFCV significantly increased with each knee extension force level (4.7 ± 1.4, 5.6 ± 1.5 and 6.2 ± 1.8 m.s-1) (p<0.01), along with RMS amplitude (p<0.0001). No differences in MFCV were found between squat loads, whilst RMS amplitude significantly increased with load (p<0.0001). Power (1920 ± 143 versus 1407 ± 254 W) and MFCV (5.7 ± 1.4 versus 4.6 ± 1.0 m.s-1) significant decreased (p<0.001) from the start to the end of the squat jump trial, with RMS amplitude unchanged. Therefore, MFCV altered with increasing fatigue, but not load, during dynamic squat exercise. It was concluded that MFCV provides useful and reliable data for acute fatigue investigations of barbell resistance exercise, in addition to sEMG amplitude measures. The following three investigations compared NM responses during and following maximum strength and power type resistance exercise sessions with different exercises, loads and movement speeds. The sessions were designed to represent elite athlete training practices, to help inform the optimisation of resistance exercise programmes. The first of these studies aimed to compare NM response to a typical maximum strength session performed with barbell squat or deadlift exercise. The purpose was to assess if technical differences between the exercises, influenced the acute NM response. Nine elite trained weightlifters performed the trial sessions of five sets of five repetitions on separate days. Normalised RMS amplitude, MFCV and power was continually measured during exercise repetitions, using the methods established above. NM function was assessed pre- and post- sessions using MVC force, central activation ratio (CAR) from superimposed stimulation during MVC, and jump performance (CMJ). The exercises were performed with subjectively matched load levels, corresponding to active muscle RPE = 17 (Borg scale), and also with controlled lifting speed. However, the squat load was lowered and raised upon the lifter’s back, whilst deadlift load was grasped in the hands, raised from the floor and then dropped. Repetition mean power was unchanged within and across sets of both sessions. Repetition RMS amplitude significantly increased (p<0.001) within sets of squat and deadlift, whilst a significant interaction between sessions and set (p<0.001) demonstrated RMS increased more during squat. Furthermore, a significant reduction in repetition MFCV was found within sets of squat (p = 0.034), but not deadlift. This suggests that motor unit activation increased during both exercises, as a response to the task of maintaining power during repetitions of whole body lifting. However, acute fatigue within squat sets led to additional increased activation as a NM compensation strategy. No pre- versus post- session differences were found for MVC, CAR or CMJ; suggesting minimal change in NM function occurred following five sets of maximum strength type resistance exercise, in well-trained subjects. The primary aim of the second study was to compare NM response and 24-hour recovery following barbell exercise maximum strength and power type sessions. The purpose was to specifically establish the degree and nature of NM response, as previous findings were unclear and barbell exercise sessions of this type have not been compared. 10 elite sprint athletes performed sessions comprising squat, split squat and push press, with four sets x repetitions per exercise. The maximum strength session exercises involved loads corresponding to active muscle RPE = 17 (Borg scale) and metronome controlled movements. The power session exercises used 30% of the maximum strength barbell load, performed as fast as possible. Repetition sEMG and power was monitored throughout each session, as above. NM function was assessed, pre-, post- and 24-hour post- each session, using the same tests as above. However, evoked peak twitch force (Pt) was also included to the pre- and post- assessments. Overall, the maximum strength session involved greater total work (p = 0.008), but lower mean power during exercise repetitions (p<0.001) in comparison to the power session. MVC and Pt force values both significantly decreased (p<0.05) pre- versus post- both sessions. However, MVC reduced more following maximum strength session (p<0.01). CAR and CMJ were unchanged post-both sessions and no differences were found between pre and 24-hour post session NM tests. The decreased Pt but not CAR findings, suggest peripheral fatigue explains the reduced force generation capacity following maximum strength and power sessions, contrary to previous resistance exercise session findings. Up to 24-hours may be required to recover force generation capacity following this volume of resistance exercise.

The purpose of this study was to investigate whether 3 days of dietary nitrate supplementation has positive effects on exercise performance and energy metabolism at rest and during strenuous knee exercise, and exercise recovery. The experimental protocol was a double blind, placebo-controlled, two-period, and within-subjects design. Fourteen healthy nonsmoking males (22.71 ± 0.72yr, 72.93 ± 2.35kg, and 47.67 ± 1.56 ml/kg/min VO2max) participated in the study. Two supplements (nitrate lozenge; NO-L or placebo; PLA) were orally administrated randomly at 48 and 24 hours before each trial day and again 40 minutes before each exercise trial. Total work, peak torque, and respiratory gases were automatically collected during repeated knee extensions/flexions (isokinetic concentric contractions with dominant leg; 4 sets of 28 repetitions at 180°/sec with 30 sec rest intervals) and recovery (6 contractions of 1 repetition maximum with 120 vii sec between contractions). For these results, peak torque, rate of fatigue, work efficiency, and rate of recovery were calculated. Blood specimens were collected at rest before and after the treatment, post exercise, and end of recovery to track the changes in blood glucose and lactate concentrations. There was a significant inverse correlation for total work during knee extension exercise and oxygen consumption (PLA: r = -.560 and NO-L: r = -.546; p < .01, respectively). During the exercise, RER was significantly higher for PLA compared with NO-L (PLA: 1.42 ± 0.02 vs. NO-L: 1.38 ± 0.02: p = .03). Work within each set and total work performed were higher for NO-L, but these differences were not significant. However, NO-L enhanced exercise efficiency by 3.3% when compared with PLA (PLA: 2497.5 ± 134.56 ft-lb/L/min vs. NO-L: 2578.7 ± 132.24 ftlb/L/min; p = .05). Extensor peak torque recovery rate slope was not significant, but meaningfully faster for NO-L (PLA: 2.39 ± 0.52% vs. NO-L: 3.06 ± 0.54%; p = .09) and significant interaction effect (p = .02) was found during recovery contractions, especially from contractions 2 to 3 (p = .03). It is also worth noting that differences in time to peak torque during knee extension exercise for NO-L and PLA approached significances (PLA: 0.213 ± 0.01 sec vs. NO-L: 0.200 ± 0.01 sec; p = .08). The results suggest that 3 days of dietary nitrate supplementation improves rate of exercise recovery and enhances work efficiency during vigorous resistance exercise. / text

Aerobic exercise interventions involving individuals with type 1 diabetes have had little positive effect on blood glucose control as reflected by hemoglobin A1c. The few existing interventions involving resistance exercise, either alone or combined with aerobic exercise, while small in sample size, have had better outcomes. The purpose of this research program was to examine the changes in blood glucose levels during activity and for 24 hours post-exercise (as measured by continuous glucose monitoring) when resistance exercise is performed, either on its own or combined with aerobic exercise, as compared to aerobic exercise alone or no exercise. Twelve physically active individuals with type 1 diabetes performed 5 separate exercise sessions in random order separated by at least five days: 1) no exercise/control; 2) aerobic exercise (45 minutes of treadmill running at 60% VO2peak); 3) resistance exercise (45 minutes of weight lifting – 3 sets of 8 repetitions of 7 different exercises); 4) aerobic then resistance exercise (2 and 3 combined with the aerobic exercise first); 5) resistance then aerobic exercise (2 and 3 combined with the resistance exercise first). We found that resistance exercise was associated with a lower risk of hypoglycemia during exercise, less carbohydrate intake during exercise, less post-exercise hyperglycemia and more frequent (but less severe) nocturnal hypoglycemia than aerobic exercise. When aerobic and resistance exercise were combined, performing resistance exercise prior to aerobic exercise (rather than the reverse) resulted in attenuated declines in blood glucose during aerobic exercise, accompanied by a lower need for carbohydrate supplementation during exercise and a trend towards milder post-exercise nocturnal hypoglycemia.