Felipe Romano Damas Nogueira

Sixteen weeks of resistance training can decrease the risk of metabolic syndrome in healthy postmenopausal women.

Background The postmenopausal phase has been considered an aggravating factor for developing metabolic syndrome. Notwithstanding, no studies have as yet investigated the effects of resistance training on metabolic syndrome in postmenopausal women. Thus, the purpose of this study was to verify whether resistance training could reduce the risk of metabolic syndrome in postmenopausal women. Methods Twenty postmenopausal women were randomly assigned to a resistance training protocol (n = 10, 53.40 ± 3.95 years, 64.58 ± 9.22 kg) or a control group (n = 10, 53.0 ± 5.7 years, 64.03 ± 5.03 kg). In the resistance training protocol, ten exercises were performed, with 3 × 8−10 maximal repetitions three times per week, and the load was increased every week. Two-way analysis of variance was used to evaluate specific metabolic syndrome Z-score, high density lipoprotein cholesterol, fasting blood glucose, triglycerides, waist circumference, blood pressure, strength, and body composition. The level of statistical significance was set at P < 0.05. Results The main results demonstrated a significant decrease of metabolic syndrome Z-score when the postmenopausal women performed resistance training (P = 0.0162). Moreover, we observed decreases in fasting blood glucose for the resistance training group (P = 0.001), and also significant improvements in lean body mass (P = 0.042, 2.46%), reduction of body fat percentage (P = 0.001, −6.75%) and noticeable increases in muscle strength after resistance training to leg press (P = 0.004, 41.29%) and bench press (P = 0.0001, 27.23%). Conclusion It was concluded that resistance training performed three times a week may reduce the metabolic syndrome Z-score with concomitant decreases in fasting blood glucose, improvements in body composition, and muscle strength in postmenopausal women.

Comparison of maximal muscle strength of elbow flexors and knee extensors between younger and older men with the same level of daily activity.

Background Aging promotes neuromuscular loss, significantly reducing muscle strength. The magnitude of loss of strength seems to be different between the limbs, probably because of differences in activities of daily living (ADL). Therefore, the present study compared the muscle strength of the elbow flexors and knee extensors in younger (n = 7, mean age 23.3 ± 1.2 years) and older (n = 5, mean age 61.8 ± 2.6 years) men matched by ADL level. Methods The study participants performed maximal concentric, isometric, and eccentric contractions of the elbow flexors and knee extensors using an isokinetic dynamometer following a crossover study design. Changes in the dependent variables were compared using mixed model analysis (limb versus age). Results The main results demonstrated that concentric, eccentric, and mean contraction torques for knee extensors were significantly (P < 0.05) higher for younger men than for elderly men. On the other hand, no statistically significant difference (P > 0.05) was found in concentric, isometric, eccentric, and mean torques for elbow flexors between younger and older individuals. Conclusion These results show that elbow flexors maintain better strength than knee extensors through aging, even when comparing individuals with similar ADL levels.

Comparison in responses to maximal eccentric exercise between elbow flexors and knee extensors of older adults

OBJECTIVES To compare the susceptibility of elbow flexors (EF) and knee extensors (KE) to eccentric exercise-induced muscle damage in older individuals, since ageing could modulate the difference in the susceptibility to muscle damage between muscles. DESIGN Cross-sectional and cross-over study design. METHODS Eight older (61.6 ± 1.8 years) adults performed 5 sets of 6 maximal isokinetic (90° s(-1)) eccentric contractions of the EF (range of motion: 80-20°) and KE (30-90°) with the non-dominant limb in a randomised, counterbalanced order with 2 weeks between bouts. Maximal voluntary isometric (MVC-ISO) and concentric contraction torque, optimum angle, range of motion (ROM), muscle soreness and serum creatine kinase (CK) activity were measured before, immediately after (except CK), and 24, 48, 72 and 96 h following exercise. Normalised changes in the variables following exercise were compared between EF and KE by a mixed model analysis of variance. RESULTS Only MVC-ISO and ROM demonstrated significant group effects (p<0.05) for the comparison between EF and KE. Additionally, no significant group vs. time interactions (p>0.05) were found between EF and KE for any of the dependent variables changes. CONCLUSIONS These results suggest that the KE of older adults are relatively as susceptible to muscle damage as their EF, or at the very least, the difference between EF and KE are small for older adults.

Immune responses to an upper body tri‐set resistance training session

The purpose of this study was to evaluate the acute immune responses to an upper body tri‐set resistance training (RT) session in RT trained individuals. Eighteen young trained men (22·0 ± 1·8 years) were randomly assigned to an exercise group (EG; n = 9) or control group (CG; n = 9). The EG completed an acute tri‐set RT protocol using two combinations of three exercises for the same muscle group with six to eight repetitions at 75% of one repetition maximum (1RM) for each exercise. Blood samples were collected before (Pre), and 15 min (Post) and 24 h (P24h) after the acute RT protocol to determine basal and acute total leucocytes and leucocyte subsets counting, interleukin‐6 (IL‐6), tumour necrosis factor‐α (TNF‐α) and cortisol. There were significant increases in total leucocytes, monocytes and neutrophils at Post as compared with Pre (P<0·05). Additionally, total leucocytes and monocytes were reduced even at P24h when compared to Pre (P<0·05). There were no significant changes in plasma concentrations of TNF‐α, IL‐6 and cortisol throughout the measured moments. As compared to CG, EG demonstrated very large effect sizes for total leucocytes, neutrophils and monocytes 15 min postprotocol and a reduction (trivial and small effect sizes) P24h. These results suggest that the tri‐set RT session did not exacerbate the acute inflammatory response and might be a good option for variations in RT methods for trained individuals.

Acute hormonal responses following different velocities of eccentric exercise.

The aim of this study was to compare the acute hormonal responses following two different eccentric exercise velocities. Seventeen healthy, untrained, young women were randomly placed into two groups to perform five sets of six maximal isokinetic eccentric actions at slow (30° s−1) and fast (210° s−1) velocities with 60‐s rest between sets. Growth hormone, cortisol, free and total testosterone were assessed by blood samples collected at baseline, immediately postexercise, 5, 15 and 30 min following eccentric exercise. Changes in hormonal responses over time were compared between groups, using a mixed model followed by a Tukeys post hoc test. The main findings of the present study were that the slow group showed higher growth hormone values immediately (5·08 ± 2·85 ng ml−1, P = 0·011), 5 (5·54 ± 3·01 ng ml−1, P = 0·004) and 15 min (4·30 ± 2·87 ng ml−1, P = 0·021) posteccentric exercise compared with the fast group (1·39 ± 2·41 ng ml−1, 1·34 ± 1·97 ng ml−1 and 1·24 ± 1·87 ng ml−1, respectively), and other hormonal responses were not different between groups (P>0·05). In conclusion, slow eccentric exercise velocity enhances more the growth hormone(GH) response than fast eccentric exercise velocity without cortisol and testosterone increases.

The effect of eccentric contraction velocity on muscle damage: A review

Abstract . The velocity at which eccentric exercise is performed may be a factor in the extent of muscular damage. However,studies differ regarding the exercise velocity that promotes greater muscle damage. The purpose of this review was to analyzestudies that looked into at least two different eccentric exercise velocities and verified markers of muscle damage. Relevantstudies for this review were identified and the methodological quality of each study was calculated based on the PhysiotherapyEvidence Database (PEDro) scale. Twelve studies were included herein. The mean PEDro rating was 6.67, ranging from 5to 7. Seven studies reported that the faster eccentric exercise velocity induced greater muscle damage. Four studies showedno differences between velocities and a single study has indicated a greater magnitude of muscle damage after slow eccentricexercise. Therefore, it seems that fast eccentric exercise may indeed be associated with greater muscle damage even thoughexercise velocity per se is not the main factor involved in eccentric exercise-induced muscle damage in both animal and humanmodels.Keywords: Resistance training, muscle strength, creatine kinase, eccentric exercise

Muscle soreness and creatine kinase activity after eccentric actions: a cluster analysis

Introduction: Maximal eccentric exercise promotes decreases in muscular strength, increases in delayed-onset muscle soreness (DMIT) and leakage of creatine kinase (CK) in the blood. However, these responses to eccentric exercise demonstrated large inter-individual variability. Objectives: To classify and analyze these responses according to individual vulnerability through the magnitude of the reduction of strength following eccentric exercise. Methods: Eighteen healthy subjects (11 men and seven women aged 18 to 71 years) performed five sets of six maximal isokinetic eccentric actions of the elbow flexors using an isokinetic dynamometer (90°s-1, range of motion 80-20°). Maximum voluntary concentric muscle contraction (CVM), DMIT and CK pre-, post (except CK), 24h, 48h, 72h and 96h were analyzed after the protocol. Individuals were classified as “low” (BR) and “high” (AR) responders at the peak of CVM decrease post-exercise using a k-means cluster analysis and compared between groups for CVM, DMIT and CK with independent t-test. Results: The comparison between BR and AR showed higher CVM decrease for AR (AR: -30.7±3.3%, BR: -14.1±2.2%, p<0.001) and higher DMIT also for AR group (AR: 33.0±8.6 mm; BR: 10.2±2.5 mm, p=0.033) however, the peak values of CK activity did not differ between groups (AR: 232.1±54.8 UI.L-1, BR: 306.1±82.3 UI.L-1, p=0.490). Conclusion: The classification of the subjects into low and high responders groups was important to demonstrate that the most responsive group to strength decrease after eccentric exercise also shows higher DMIT levels; notwithstanding, for creatine kinase this relation could not be established.

Dano muscular: resposta inflamatória sistêmica após ações excêntricas máximas

O objetivo deste estudo foi analisar a resposta inflamatoria induzida por grande numero de acoes excentricas (AE) maximas realizadas pelos flexores do cotovelo. Participaram do estudo nove homens jovens, que realizaram 35 series de seis AE nos flexores de cotovelo, com intervalo de um minuto, utilizando um dinamometro isocinetico em uma velocidade de 210o.s-1. As variaveis mensuradas foram: a contracao isometrica voluntaria maxima (CIVM), a amplitude de movimento (AM), a dor muscular de inicio tardio (DMIT), a interleucina-6 (IL-6) e o fator de necrose tumoral alfa (TNF-α). Alteracoes significantes foram observadas para os marcadores indiretos de dano muscular (CIVM, AM e DMIT), entretanto nao houve modificacoes para os marcadores inflamatorios (IL-6 e TNF-α). Em conclusao, os resultados demonstraram que mesmo com alteracoes nos marcadores indiretos de dano muscular apos a realizacao de um grande numero de AE nao foram observadas alteracoes na resposta inflamatoria sistemica.

Dolor muscular y actividad de creatina kinasa tras acciones excéntricas: un análisis de cluster

Introduction: Maximal eccentric exercise promotes decreases in muscular strength, increases in delayed-onset muscle soreness (DMIT) and leakage of creatine kinase (CK) in the blood. However, these responses to eccentric exercise demonstrated large inter-individual variability. Objectives: To classify and analyze these responses according to individual vulnerability through the magnitude of the reduction of strength following eccentric exercise. Methods: Eighteen healthy subjects (11 men and seven women aged 18 to 71 years) performed five sets of six maximal isokinetic eccentric actions of the elbow flexors using an isokinetic dynamometer (90°s-1, range of motion 80-20°). Maximum voluntary concentric muscle contraction (CVM), DMIT and CK pre-, post (except CK), 24h, 48h, 72h and 96h were analyzed after the protocol. Individuals were classified as “low” (BR) and “high” (AR) responders at the peak of CVM decrease post-exercise using a k-means cluster analysis and compared between groups for CVM, DMIT and CK with independent t-test. Results: The comparison between BR and AR showed higher CVM decrease for AR (AR: -30.7±3.3%, BR: -14.1±2.2%, p<0.001) and higher DMIT also for AR group (AR: 33.0±8.6 mm; BR: 10.2±2.5 mm, p=0.033) however, the peak values of CK activity did not differ between groups (AR: 232.1±54.8 UI.L-1, BR: 306.1±82.3 UI.L-1, p=0.490). Conclusion: The classification of the subjects into low and high responders groups was important to demonstrate that the most responsive group to strength decrease after eccentric exercise also shows higher DMIT levels; notwithstanding, for creatine kinase this relation could not be established.

Dor muscular e atividade de creatina quinase após ações excêntricas: uma análise de cluster

Introduction: Maximal eccentric exercise promotes decreases in muscular strength, increases in delayed-onset muscle soreness (DMIT) and leakage of creatine kinase (CK) in the blood. However, these responses to eccentric exercise demonstrated large inter-individual variability. Objectives: To classify and analyze these responses according to individual vulnerability through the magnitude of the reduction of strength following eccentric exercise. Methods: Eighteen healthy subjects (11 men and seven women aged 18 to 71 years) performed five sets of six maximal isokinetic eccentric actions of the elbow flexors using an isokinetic dynamometer (90°s-1, range of motion 80-20°). Maximum voluntary concentric muscle contraction (CVM), DMIT and CK pre-, post (except CK), 24h, 48h, 72h and 96h were analyzed after the protocol. Individuals were classified as “low” (BR) and “high” (AR) responders at the peak of CVM decrease post-exercise using a k-means cluster analysis and compared between groups for CVM, DMIT and CK with independent t-test. Results: The comparison between BR and AR showed higher CVM decrease for AR (AR: -30.7±3.3%, BR: -14.1±2.2%, p<0.001) and higher DMIT also for AR group (AR: 33.0±8.6 mm; BR: 10.2±2.5 mm, p=0.033) however, the peak values of CK activity did not differ between groups (AR: 232.1±54.8 UI.L-1, BR: 306.1±82.3 UI.L-1, p=0.490). Conclusion: The classification of the subjects into low and high responders groups was important to demonstrate that the most responsive group to strength decrease after eccentric exercise also shows higher DMIT levels; notwithstanding, for creatine kinase this relation could not be established.