Introduction Weight loss practices are commonly used by athletes who perceive lower levels of body fat and higher fat-free mass (FFM) as advantageous for physical performance. High protein diets have been associated with greater fat loss and greater retention of lean mass during periods of energy restriction (ER) in individuals with obesity. However, less is known about the effects of high protein diets in trained individuals during ER. It has been proposed that leaner individuals are more at risk of losing FFM during ER than individuals with overweight. The current ACSM recommendation for protein intake in active individuals is 1.2-1.7g/kg. However, it is unclear whether higher intakes are necessary to maximize FFM retention and maximize physical performance in athletes undergoing periods of ER. Objective Our primary objective was to determine whether high protein intakes could maximize FFM retention in trained individuals during periods of ER. We also aimed to determine whether higher protein intakes are superior at maintaining physical performance. Lastly, we aimed to determine whether high protein intakes could mitigate adaptive thermogenesis (AT) in response to ER. Methods Twelve college aged athletes (6 women and 6 men) from various sports were analyzed in this study. They underwent a 6-week 25% reduction in energy intake along side a 3-day full body resistance training program. Participants were randomly assigned to a low (~1.2g/kg), moderate (~1.6g/kg) or high (~2.2g/kg) protein group. Baseline and post-intervention measures were obtained via Dual X-ray absorptiometry (DXA), isotopic water dilution, indirect calorimetry, dietary records and strength based physical testing. Results Our results indicate a main effect of the intervention on fat mass reductions (19.66 ± 9.05 kg vs 18.02 ± 8.07 kg) (p = 0.016) despite non-significant reductions in body weight (p = 0.059). No significant changes in FFM were observed (p = 0.307). Significant increases in chest press 5RM strength (43.18 ± 14.95 kg vs 48.86 ± 17.46 kg) and chin-up maximal repetition (4.75 ± 5.64 vs 6.08 ± 6.56) were observed across all groups from baseline to post-intervention (p < 0.05). No significant increases in strength were noted on lower body movements. Resting energy expenditure (REE) was significantly reduced after the 6-week intervention (1743.52 ± 295.74 kcal vs 1655.18 ± 263.23 kcal) (p = 0.006). What is more, post-intervention measured and predicted REE were also significantly different (1655.18 ± 263.23 kcal vs 1747.92 ± 263.20) (p = 0.012). No significant effects of protein were noted on any of the outcomes. Conclusion Our preliminary results indicate that the ACSM recommendation of 1.2-1.7g/kg is sufficient for most athletes even during periods of ER to maintain FFM and physical performance. We also found the possibility of early AT in that population independently of protein intake. In fact, REE was reduced by ~100 kcal/day more than predicted despite minimal weight loss and relative preservation of FFM.

Recent recommendations are that older adults increase their dietary protein intake to intakes higher than are currently recommended to mitigate sarcopenia-induced muscle loss caused in part by anabolic resistance. Protein supplementation may serve as an effective strategy to meet protein intake goals; however, protein supplements vary in their quality, which may impact muscle protein turnover. Protein quality is determined by the digestibility and content of essential amino acids in a protein source and may play an important role in mitigating the loss of muscle mass and muscle protein synthesis (MPS) during energy restriction (ER), acute reductions in physical activity, which we modeled using enforced step reduction (SR), and during recovery from SR. We aimed to determine whether the quality of a protein supplement – whey protein (higher quality) versus collagen peptides (lower quality) – would impact the reduction in fat-free bone-free mass (FBFM) and MPS (Study 1), and also to compare differences in functional variables: strength loss in men and women, and single fibre function with SR in men (Study 2). In Studies 1 and 2 we compared supplementation with whey protein (WP) and collagen peptides (CP), higher and lower quality proteins respectively, as part of a higher protein diet provided to older adults during one week of ER (-500 kcal/d), two weeks of step reduction (< 750 steps/d) (ER+SR) and one week of recovery (RC). Two weeks of ER+SR significantly reduced FBFM in both the WP and CP groups with greater FBFM recovery with WP. MPS was significantly reduced following ER in both groups and did not decrease further during ER+SR. MPS was increased above ER+SR following 1 week of RC in the WP group only. ER+SR significantly reduced maximum voluntary contraction (MVC) in both men and women; however, following RC men fully recovered their strength and women did not. In Study 3, we aimed to determine the impact of WP and CP supplementation combined with unilateral resistance exercise (RE) to augment the acute and longer term MPS response in healthy older women. Acutely, rates of MPS were elevated following WP+RE and with WP alone while MPS was elevated only in CP+RE. Six days of supplementation increased MPS in WP and WP+RE with no increase in MPS with CP or CP+RE. Collectively, these studies demonstrate that protein quality is an important variable to consider in selecting a protein supplement for older adults and for recovering from inactivity. / Thesis / Doctor of Science (PhD) / At the end of the 5th decade of life, adults will have lost an appreciable amount of muscle mass and strength versus what they had in their 3rd decade of life. This age-related loss of muscle mass and strength is known as sarcopenia. Additionally, as they age, adults will experience brief periods of reduced physical activity due to illness, injury, or recovery from surgery. Such periods are associated with a rapid loss of muscle and strength creating a brief period of ‘accelerated sarcopenia’. Strategies to combat the loss of muscle and strength in these periods include increasing protein intake and even periodic exercise which may help to reduce the negative impact of physical inactivity. In particular, higher quality protein sources (protein derived from animal sources or soy) and weightlifting may better help muscles recover from inactivity. Our main findings were that consuming high quality protein (whey protein) stimulated the process of muscle building that is normally reduced with inactivity. Importantly, when combined with resistance exercise, we were able to increase the rate at which healthy older women built muscle with whey protein in comparison to a lower quality protein source (collagen peptides). These findings provide novel and insightful information for the recommendations of protein supplement types to older adults to increase daily protein intake to preserve muscle mass with age.

Yes / Maintenance of skeletal muscle mass and function is critical to health and wellbeing throughout the lifespan. However, disuse through reduced physical activity (e.g., sedentarism), immobilisation, bed rest or microgravity has significant adverse effects on skeletal muscle health. Conversely, resistance exercise training (RET) induces positive muscle mass and strength adaptations. Several studies have employed microarray technology to understand the transcriptional basis of muscle atrophy and hypertrophy after disuse and RET, respectively, to devise fully effective therapeutic interventions. More recently, rapidly falling costs have seen RNA-sequencing (RNA-seq) increasingly applied in exploring muscle adaptations to RET and disuse. The aim of this review is to summarise the transcriptional responses to RET or disuse measured via RNA-seq in young and older adults. We also highlight analytical considerations to maximise the utility of RNA-seq in the context of skeletal muscle research. The limited number of muscle transcriptional signatures obtained thus far with RNA-seq are generally consistent with those obtained with microarrays. However, RNA-seq may provide additional molecular insight, particularly when combined with data-driven approaches such as correlation network analyses. In this context, it is essential to consider the most appropriate study design parameters as well as bioinformatic and statistical approaches. This will facilitate the use of RNA-seq to better understand the transcriptional regulators of skeletal muscle plasticity in response to increased or decreased use.

Distortion to hemodynamic, ischemic and metabolic stimuli during low load resistance exercise with blood flow restriction (BFR) may influence regional vascular adaptation. This thesis investigated the acute response and chronic adaptations of the peripheral vasculature to low load resistance exercise with BFR. The methodology utilised Doppler ultrasound, strain gauge plethysmography and muscle biopsy for insightful measures of the vasculature at different regions of the arterial tree. Short term (4-6 weeks) localised low load (30-40% 1RM) resistance exercise with BFR increased brachial (3.1%) and popliteal (3.3%) artery maximal diameter (in response to ischemic exercise), forearm (29%) and calf (24%) post-occlusive blood flow, and calf filtration capacity (14%). These findings indicate potential vascular remodelling at the conduit (chapters 3, 4) resistance (chapter 4) and capillary (chapter 4) level of the vascular tree. Regional, rather than systemic, factors are responsible for these adaptations as evidenced by an absent response in the contralateral control limb. Transient improvements in popliteal artery FMD% occurred at week 2 before increased maximal diameter at week 6, suggesting functional changes precede structural remodelling (chapter 4). Maximal brachial artery diameter and forearm post-occlusive blood flow returned to baseline values after a 2 week detraining period, signifying rapid structural normalisation after stimulus removal (chapter 3). Enhanced capillarity, despite low training loads, could be explained by augmentation of VEGF (~7 fold), PGC-1α (~6 fold) and eNOS (~5 fold) mRNA, and upregulation VEGFR-2 (~5 fold) and HIF-1α (~2.5 fold) mRNA with BFR (chapter 5). This indicates a targeted angiogenic response potentially mediated through enhanced metabolic, ischemic and shear stress stimuli. Large between subject variability in the level of BFR was observed during upper and lower limb cuff inflation protocols. Adipose tissue thickness and mean arterial pressure were the largest independent determinants of upper and lower limb BFR, respectively (Chapter 6). In conclusion, this thesis demonstrates that low load resistance exercise with BFR induces adaptation in the conduit, resistance and capillary vessels. The mediators of this response are likely to be the hemodynamic and chemical signals elicited by repeated bouts of BFR resistance exercise, although confirmation of these mechanisms is required. The functional significance of these adaptations is unknown and warrants further investigation.

The aim of this research was to develop a novel multi-function exercise system for use in a broad range of applications. Market research indicates that the demand for aerobic and anaerobic exercise devices will continue to grow with the introduction of government physical activity guidelines and increased social pressure regarding health related issues. A detailed investigation of the basic exercise science fundamentals and training methodologies was conducted in order to develop a system which would provide efficient and effective training related stimuli for improving fitness. The generation, storage and utilisation of actual and virtual load and velocity profiles for use in the development of original training modes was identified as an important area of the research. The proposed solution utilises an electromechanical programmable motion control system which provides all of the necessary exercise modalities defined in the system specification. This system combines existing industrial servo drive technology with proprietary software and database facilities to provide a step change in functionality, ease of use and safety for all users. Development of these hardware and software elements was supported by the creation of a series of system models at the initial stages of the research using the computer integrated manufacturing open systems architecture (CIMOSA) modelling approach. These diagrams were an invaluable resource during the concept generation and refinement processes and have clearly demonstrated the cross-discipline applications of such formalised modelling techniques. Validation and reliability data collected during prototype testing indicated that the exercise motion generation capabilities and performance measurement facilities were comparable to existing isokinetic dynamometer equipment. Additional subject testing produced results with peak output values and parameter trends which correlated closely to those determined during clinical and academic research. These experimental results suggest that the modular exercise system could be a valuable tool for the collection of research data to be used in support of current and future training theories.

Bakgrund: Regelbunden fysisk aktivitet leder till positiva hälsoeffekter och är därmed viktig som primär- och sekundärprevention för flera olika sjukdomar och för tidig död. Primärprevention ges dock begränsat utrymme inom sjukvården och därmed kan ett samarbete med andra hälsofrämjande aktörer i samhället vara motiverat. Syfte: Att undersöka om deltagare skattar högre upplevd livskvalitet och fysisk aktivitetsnivå efter Friskis&amp;Svettis (F&amp;S) tio veckor långa ”Börja träna”-kurs samt undersöka om det fanns en korrelation mellan livskvalitet och fysisk aktivitetsnivå. Metod: 95 deltagare (81 kvinnor, 14 män) med en medelålder på 50 år fyllde i två enkäter, en före och en efter interventionen. En inomgruppsjämförelse samt en korrelationsanalys gällande livskvalitet och fysisk aktivitetsnivå gjordes. Resultat: Medianen för livskvalitet var 7 före interventionen och 8 efter vilket var en signifikant ökning (p=0,022). Även för fysisk aktivitet var ökningen signifikant med en median på 3 före interventionen och 4 efter (p&lt;0,001). I studien sågs ett mycket svagt samband mellan livskvalitet och fysisk aktivitetsnivå före interventionen (r=-0,172, p=0,122). Konklusion: Efter deltagande i F&amp;S ”Börja träna”-kurs skattade deltagarna högre livskvalitet och fysisk aktivitetsnivå. På grund av ett stort bortfall och flera metodologiska felkällor bör resultatet användas med försiktighet och vidare studier är därmed nödvändiga.

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.