O objetivo da presente dissertação foi avaliar e comparar as possíveis diferenças nas adaptações cardiovasculares e funcionais ao treinamento concorrente com e sem a execução de séries com repetições até a falha concêntrica em homens idosos. Trinta e dois homens idosos saudáveis (67,4 ± 4,1) foram alocados randomicamente em três grupos diferentes de treinamento concorrente: Treinamento de força utilizando repetições máximas (GRM, n = 12), Treinamento de força com repetições submáximas (GRNM, n = 11) e Treinamento de força com repetições submáximas com volume equalizado ao realizado pelo GRM (GRNMV, n = 9). Os participantes treinavam duas vezes por semana, durante doze semanas, executando o treinamento aeróbico imediatamente após o treinamento de força. Antes e após a intervenção foi avaliado o Vo2pico através de ergoespirometria, o desempenho funcional utilizando os testes timed up and go (TUG), sentar e levantar 5 vezes (SeL) e preensão manual (PM). Coletou-se amostras de sangue para análise da glicemia, colesterol total, HDL, LDL e triglicerídeos. A pressão arterial sistólica (PAS) e pressão arterial diastólica (PAD) foram mensuradas através de método auscultatório, o desempenho de saltos através do salto agachado (SJ) e salto com contra movimento (CMJ) e a composição corporal avaliada a partir de antropometria. Após a intervenção, foi observado um efeito tempo significativo (P<0,05) no Vo2pico, sem diferenças entre os grupos. No desempenho funcional não foram observadas mudanças em nenhum dos testes. A análise sanguínea demonstrou um efeito tempo significativo (p<0,01) no HDL, sem diferenças entre os grupos, enquanto não houve variações para glicemia, LDL e triglicerídeos. Na altura dos saltos, foi verificado um efeito tempo significativo (p<0,01) no SJ e uma tendência a incremento (p<0,056) no CMJ, sem diferenças entre os protocolos de treinamento. A composição corporal foi alterada pelo treinamento, com efeito significativo na massa de gordura relativa (p<0,001), na massa livre de gordura relativa (p<0,001) e no somatório de dobras cutâneas (p<0,001), sem diferenças entre os grupos. Desta forma, foi observado que todos os protocolos de treinamento foram eficazes para promover mudanças na capacidade aeróbica, no perfil lipídico, no desempenho de saltos e na composição corporal, porém, o GRNM foi mais eficiente, pois promoveu tais adaptações com um volume de treino menor. / The aim of this study was to evaluate and compare the possible differences in cardiovascular and functional adaptations to concurrent training with and without the execution of series with repetitions until concentric failure in elderly men. Thirty-two healthy elderly men (67,4 ± 4,1) were randomly assigned to three different groups of concurrent training: strength training using maximal repetitions (GRM, n = 12), Strength training with submaximal repetitions (GRNM, n = 11), and strength training with submaximal repetitions with volume equalized to that performed by GRM (GRNMV, n = 9). Participants trained twice a week for twelve weeks, performing aerobic training immediately after strength training. Before and after the intervention, VO2peak was evaluated using a metabolic cart, functional performance using the timed up and go (TUG), sit and up 5 times (SUp) and handgrip strength (HS) tests. Blood samples were collected for analysis of glycemia, total cholesterol, HDL, LDL, and triglycerides. The systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured using the auscultatory method, the jump performance determined by squat jump (SJ) and counter-movement jump (CMJ). Body composition are evaluated through anthropometry. After the intervention, a significant time effect (P <0.05) was observed on VO2peak, with no differences between groups. In functional performance, no changes were observed in any of the tests. Blood analysis showed a significant increase (p <0.01) in HDL, with no differences between groups, whereas there were no changes for glycemia, LDL and triglycerides. In the jump performance, a significant time effect (p <0.01) was observed in the SJ and a trend toward significant increase (p <0.057) in the CMJ, without differences between the training protocols. Body composition was changed by training, with a significant time effect on the relative fat mass (p <0.001), relative fat free mass (p <0.001), and on the sum of skinfolds (p <0.001), with no differences between groups. In this way, it was observed that all training protocols were effective to promote changes in aerobic capacity, lipid profile, jumping performance and body composition, but the GRNM was more efficient, as it induced such adaptations with a lower training volume.

The primary purpose of this thesis was to assess the effect of knee-joint angle on the neuromechanics of maximal and explosive contractions, specifically torque and neuromuscular activation, as well as the influence of isometric resistance training (RT) on these variables and thus joint angle specificity of training adaptations. It was found that electrode location had a pronounced effect on surface electromyography (sEMG) amplitude during maximum isometric voluntary contractions (MVCs) and moderate relationship between subcutaneous tissue thickness and sEMG amplitude (R2=0.31 up to 0.38) was reduced but not consistently removed by maximal M-Wave (MMAX) normalization [up to R2= 0.16 (peak-to-peak) and R2= 0.23 (Area)]. Thus, MMAX peak-to-peak was the better normalization parameter that removed the influence of electrode location and substantially reduced the influence of subcutaneous tissue thickness. Maximal torque-angle relationship presented an inverted U shape with both, agonist (measure by two different techniques) and antagonist neuromuscular activation both differing with knee-joint angle and thus, both likely contributing to the torque-angle relationship. Absolute explosive torque-angle relationship exhibited higher torques at mid-range knee joint angles in a similar manner to maximal strength, whilst the ability to explosively express the available torque (i.e. relative to maximal strength) revealed only subtle differences between joint angles. Agonist neuromuscular activation showed increases from extended to flexed positions during both maximum and explosive contractions (at all time points; ~6% to ~34%) and evoked contractile properties presented opposite patterns with twitch torque increasing (~5% to ~30%) and octet torque decreasing (~2% to ~14%) with knee flexion. Finally, after 4 weeks of RT at a 65° knee-joint angle evidence of joint angle specificity was provided from both within-group (greater gains at 3 angles than others) and between-group evidence (greater gains at 2 angles than others) for maximal strength but not for explosive strength and neuromuscular activation. In summary, this thesis demonstrated: (1) higher strength values at middle knee-joint positions than more flexed and/or extended positions during maximal and explosive contractions; (2) how agonist neuromuscular activation contributes to the beforementioned changes in strength; (3) how muscle contractile properties contribute to the explosive strength across knee-joint angles; and finally (4) that joint angle specificity has a neural basis.

A prática regular de exercícios físicos durante a infância e adolescência pode induzir o crescimento e desenvolvimento tanto da massa muscular assim como da massa óssea. Nesse contexto, o exercício físico está intimamente ligado à função anabólica provocada pela ação do eixo GH/IGF-I. Níveis basais de IGF-I estão correlacionados positivamente com massa muscular em crianças, adolescentes e adultos. A cinética do IGF-I e IGFBP-3 durante o treinamento crônico ainda não está totalmente esclarecida e um ótimo estimulo para maximizar uma resposta anabólica no treinamento com pesos ainda permanece obscuro. O objetivo do presente estudo foi analisar a cinética das concentrações de IGF-I e da proteína de ligação IGFBP-3 em adolescentes submetidos a dez semanas de treinamento de hipertrofia. As concentrações séricas de IGF-I e IGFBP-3 foram determinadas na 1ª, 5ª e 10ª semana de treinamento com pesos. A composição corporal avaliada mediante cálculo da massa magra, porcentagem de gordura e do índice de massa corporal foi também realizada na 1ª, 5ª e 10ª semana de treinamento e comparada à cinética de IGF-I e da IGFBP-3. O IGF-I apresentou aumento significativo no primeiro momento de avaliação entre o pré e pós-treino (p=0,03) e ao longo das 10 semanas de treinamento (p=0,003). Em relação à IGFBP-3 não foi possível identificar variação significativa entre o pré e o pós-treino em nenhuma das avaliações ou ao longo das 10 semanas de treinamento. A massa corporal, massa magra, a porcentagem de gordura e índice de massa corporal dos voluntários mantiveram-se inalterados ao longo das 10 semanas de treinamento. Correlação negativa foi observada entre a variação na massa muscular e a variação das concentrações séricas de IGF-I quando comparados os dados das avaliações da 1ª e 10ª semanas (r=-0,62; p= 0,002). Em resumo, o IGF-I, mas não a IGFBP-3, mostrou-se sensível aos efeitos agudos e crônicos do treinamento com pesos apresentando-se como um biomarcador de estado de treinamento em voluntários não atletas. A relação negativa entre a variação do IGF-I e a variação da massa magra pode sinalizar um aumento da sensibilidade ao IGF-I com o treinamento. / Regular physical exercise during childhood and adolescence can promote growth and development of muscle mass and bone mass. In this context, physical exercise is closely linked to the anabolic function of the GH / IGF-I axis. Baseline IGF-I levels are positively correlated with muscle mass in children, adolescents and adults. The kinetics of IGF-I and IGFBP-3 during chronic training is not fully understood yet; a good stimulus to maximize the anabolic response in resistance training remains unclear. The aim of the present study was to analyse the kinetics of IGF-I and IGFbinding protein 3 (IGFBP-3) in adolescents undergoing ten weeks of hypertrophy training. Serum IGF-I and IGFBP-3 concentrations were determined at the 1st, 5th and 10th week of resistance training. Body composition, lean mass, fat percentage and body mass index were also evaluated at the 1st, 5th and 10th week and compared to the changes in serum IGF-I and IGFBP-3. IGF-I levels increased during the training session at the first evaluation (p=0,03) and also increased during the 10 weeks of training (p=0,003). No changes in IGFBP-3 levels were observed during a training session or during the 10 weeks of training. Body mass, lean mass, fat percentage and body mass index of the volunteers remained unchanged throughout the 10 weeks of training. Negative correlation was observed between the variation in muscle mass and changes in serum IGF-I when data from the 1st and the 10th weeks were compared (r=-0,62;p=0,002). In summary, IGF-I but not IGFBP-3 was sensitive to the acute and chronic effects of resistance training and can be considered as a biomarker of training status in non-athlete volunteers. The negative correlation between the variations in lean mass and IGF-I could sign to a training induced increase in IGF-I sensitivity.

OBJECTIVE: The purpose of this study was to examine the relationship between strength training and body composition before and after controlling for several covariates. A cross-sectional study including 257 female subjects was conducted. METHODS: Subjects' level of involvement in strength training was determined via questionnaire. Body composition was assessed using dual energy X-ray absorptiometry (DXA). Diet was assessed using 7-d weighed food records. RESULTS: Strong linear relationships between subjects' level of involvement in strength training and body composition were identified. For each additional day of strength training reported per week, body fat was 1.32 percentage points lower (F = 14.8, p = 0.0002) and fat-free mass was 656.4 g (1.45 lb) higher (F = 18.9, p < 0.0001), on average. Likewise, the more time subjects spent lifting and the more intensely they trained, the better their body composition tended to be. Adjusting for differences in age, menopause status, objectively measured physical activity, energy intake, and protein intake tended to weaken each association. Controlling for differences in physical activity weakened each relationship the most. CONCLUSION: Women who strength train regularly tend to have significantly lower body fat percentages and significantly higher levels of fat-free mass compared to their counterparts, regardless of differences in several potential confounding variables.

The purpose of this study was to examine the force-time differences between concentric-only half-squats (COHS) performed with ballistic (BAL) or non-ballistic (NBAL) intent across a range of loads. Eighteen resistance-trained men performed either BAL or NBAL COHS at 30%, 50%, 70%, and 90% of their one repetition maximum (1RM) COHS. Relative peak force (PF) and relative impulse from 0–50 ms (Imp50), 0–90 ms (Imp90), 0–200 ms (Imp200), and 0–250 ms (Imp250) were compared using a series of 2 × 4 (intent × load) repeated measures ANOVAs with Bonferroni post hoc tests. Cohen’s d effect sizes were calculated to provide measures of practical significance between the BAL and NBAL COHS and each load. BAL COHS produced statistically greater PF than NBAL COHS at 30% (d = 3.37), 50% (d = 2.88), 70% (d = 2.29), and 90% 1RM (d = 1.19) (all p < 0.001). Statistically significant main effect differences were found between load-averaged BAL and NBAL COHS for Imp90 (p = 0.006, d = 0.25), Imp200 (p = 0.001, d = 0.36), and Imp250 (p < 0.001, d = 0.41), but not for Imp50 (p = 0.018, d = 0.21). Considering the greater PF and impulse observed during the BAL condition, performing COHS with BAL intent may provide a favorable training stimulus compared to COHS performed with NBAL intent.

Objectives: The purpose of this study was to examine the relationship of velocities in the back squat between one repetition maximum (1RM) and submaximally loaded repetition maximum (RM) conditions, specifically in regard to what has been described as the minimal velocity threshold (MVT). The MVT describes a minimum concentric velocity that an individual must reach or surpass in order to successfully complete a repetition. Design: To test the presence of a MVT, participants were tested for 1RM and RM back squat ability. The mean concentric veloci ties (MCV) of the last successful repetition of each condition were then compared. Methods: Fourteen male participants familiar with the back squat volunteered to participate in the current study (age = 25.0 y ± 2.6, height = 178.9 cm ± 8.1, body mass = 88.2 kg ± 15.8). The mean concentric velocity (MCV) during the last successful repetition from each testing condition was considered for the comparison. Results: Results indicated a non-significant negative relationship of MCV between the 1RM and RM conditions (r = -0.135), no statistical difference between testing conditions (p = 0.266), with a small-to-moderate effect size (d = 0.468). Conclusions: The results of this study suggest that MVT should be further investigated to enhance its use in the practical setting. Additionally, coaches considering using a velocity-based approach for testing athletes should use data from either 1RM or RM conditions, but not both interchangeably. Coaches should be cautious when considering group averages or comparing velocity data between athletes, which may not be appropriate based on our results.

Abstract available in the Medicine and Sciences in Sports and Exercise.

Complex training is commonly utilized in an attempt to facilitate peak power production and Rate of Force Development (RFD) via Post Activation Potentiation (PAP). This research compared the effects of six weeks of; resistance (RT), plyometric (PT), and complex training (CT) upon the relationship between peak ground reaction forces (pGRF), jump performance, and strength. Thirty-four recreationally trained college aged males (21.44 ± 3.32 years) were trained using 1 of 3 methods; resistance (RT; n = 13; 180.14 ± 4.75 cm; 83.85 ± 20.54 kg), plyometric (PT; n = 11; 181.41 ± 7.97 cm; 81.25 ± 10.43 kg), or complex training (CT; n = 10; 185.17 ± 5.56 cm; 87.54 ± 9.04 kg) twice a week for 6 weeks. Participants were tested pre (W1) and post (W9) training to assess vertical jump height (CMVJ; cm), broad jump distance (BDJ; cm), pGRF (N), and multiple 1RM (kg) strength measures. Correlation matrices calculated on % change scores for performance measures from W1 to W9 between conditions, revealed significant positive and negative correlations (r range = -.730 through .996; p < .01* and p < .05**). The greatest total of significant correlation coefficients (r) for % change was seen for the RT group. Differences in training adaptations between groups at both the muscular and neuromuscular level may account for the differences seen.

This study examined the kinetic and kinematic differences between accentuated eccentric loading (AEL) and cluster sets in trained male subjects (age = 26.1 ± 4.1 years, height = 183.5 ± 4.3 cm, body mass = 92.5 ± 10.5 kg, and back squat to body mass ratio = 1.8 ± 0.3). Four load condition sessions consisted of traditionally loaded (TL) “straight sets,” TL cluster (TLC) sets, AEL cluster (AEC) sets, and AEL “straight sets” where only the first repetition had eccentric overload (AEL1). An interrepetition rest interval of 30 seconds was prescribed for both TLC and AEC. Concentric intensity for all load conditions was 80% 1 repetition maximum (1RM). Accentuated eccentric loading was applied to repetitions using weight releasers with total eccentric load equivalent to 105% of concentric 1RM. Traditionally loaded cluster had statistically greater concentric outputs than TL. Furthermore, statistically greater eccentric and concentric outputs were observed during AEC compared with TL with the exception of peak power. Statistically greater concentric characteristics were observed in TLC compared with AEL1, but statistically greater eccentric outputs were observed in AEL1. In the 2 cluster set conditions, statistically greater concentric rate of force development (RFDCON) (d = 0.470, p < 0.001) and average velocity (vavg) (d = 0.560, p < 0.001) in TLC compared with AEC were observed. However, statistically greater eccentric work (WECC) (d = 2.096, p < 0.001) and eccentric RFD (RFDECC) (d = 0.424, p < 0.001) were observed in AEC compared with TLC. Overall, eccentric overload demonstrated efficacy as a means of increasing eccentric work and RFD, but not as a means of potentiating concentric output. Finally, interrepetition rest seems to have the largest influence on concentric power output and RFD.

The introduction of novel training stimuli plays a crucial role in inducing specific training adaptations. One method that can be employed to introduce a novel stimulus to the training program while maximizing the velocity and power output of the training exercise is the inclusion of the cluster set configuration. The current review presents the theoretical and research foundation for the use of the cluster set in periodized training programs and offers examples of practical applications that can be used in the preparation of athletes in a variety of sports.