Combined training is not superior to strength and aerobic training to mitigate cardiovascular risk in adult healthy men.

Although the beneficial effects of aerobic training on cardiovascular risk factors are evident, the potential beneficial effect of strength and combined training on these risk factors is controversial. This study aimed to evaluate the effect of aerobic and strength training programmes, performed alone or in combination, on cardiovascular risk factors in sedentary, apparently healthy and non-obese adult men. The study was conducted with 37 subjects who were randomly divided into the following groups: aerobic (AG), combined (ASG), strength (SG) and control (CG). The exercise programmes were performed three times a week and lasted approximately 50 minutes. Dietary intake, anthropometry, blood pressure, muscular strength, aerobic capacity, lipid profile and glycaemic control were assessed before and after 12 weeks of the intervention. One-way analysis of variation (ANOVA) for baseline, and ANOVA for repeated measures were used to assess differences between the initial and final time points of the four groups. Changes in blood pressure and glycaemic control were not significant in any of the groups. No differences were observed in LDL-C between training groups. HDL-C increased significantly only in the AG. In conclusion, if minimal changes in the lipid profile are needed, an aerobic training programme can provide possible benefits for HDL-C in apparently healthy and non-obese adult men.

Effects of Local Vibration on Dynamic Strength Training.

ABSTRACT: Drummond, MDM, Couto, BP, Oliveira, MP, and Szmuchrowski, LA. Effects of local vibration on dynamic strength training. J Strength Cond Res 35(11): 3028-3034, 2021-The study aim was to compare the chronic effects of maximal dynamic strength training with and without the addition of local vibration (LV) on maximal force generation and hypertrophy of the elbow flexor muscles in trained subjects. Twenty men were divided into 2 groups (conventional training [CT] group and vibration training [VT] group). The CT group performed conventional maximal dynamic strength training, and the VT group performed maximal dynamic strength training with mechanical vibrations (frequency of 26 Hz and amplitude of 6 mm). CT and VT groups performed 5 sets of 3-4 repetitions, with 2-minute rest intervals between sets. The subjects trained 3 times per week for 12 weeks. After the training period, the CT group presented a significant increase in the mean 1 repetition maximum (1RM) value in the elbow flexion exercise in the orthostatic position (EFO) (7.2 ± 1.5%) (p < 0.0001) and elbow flexion exercise using the Scott bench (EFSB) (6.3 ± 1.8%) (p < 0.0001). The VT group also showed significant increases in 1RM values in the EFO (6.87 ± 0.8%) (p < 0.0001) and EFSB (6.56 ± 1.4%) (p < 0.0001). The CT group presented a significant increase in the mean maximal voluntary isometric contraction (MVIC) value after the training period (8.2 ± 2.3%) (p < 0.0001). The VT group also showed a significant increase in the mean MVIC value after training (9.1 ± 2.4%) (p < 0.0001). After the training period, both groups presented a significant increase in the mean value of elbow flexor thickness (CT = 5.6 ± 3.5%, VT = 5.1 ± 2.8%) (p = 0.001). The increases in 1RM, MVIC, and muscle thickness were statically similar between groups. Therefore, the addition of LV does not represent an additional stimulus for individuals trained in dynamic maximal strength training.

Effect of strength training on regional hypertrophy of the elbow flexor muscles.

INTRODUCTION: Muscle hypertrophy is the main structural adaptation to strength training. We investigated the chronic effects of strength training on muscle hypertrophy in different regions of the elbow flexor muscles. METHODS: Eleven untrained men (21.8 ± 1.62 years) underwent magnetic resonance imaging to determine the proximal, medial, distal, and mean cross-sectional areas (CSA) of the elbow flexors. The volunteers completed 12 weeks of strength training. The training protocol consisted of 4 sets of 8-10 maximum repetitions of unilateral elbow flexion. The interval between sets was 120 s. The training frequency was 3 sessions per week. RESULTS: The magnetic resonance images verified the presence of significant and similar hypertrophy in the distal, medial, and proximal portions of the elbow flexor muscles. CONCLUSIONS: Muscle hypertrophy may be assessed using only the medial CSA. We should not expect different degrees of hypertrophy among the regions of the elbow flexor muscles. Muscle Nerve 54: 750-755, 2016.

Analysis of lower limb asymmetries by isokinetic and vertical jump tests in soccer players.

Assessment of lower extremity bilateral asymmetries in soccer players is important for both injury prevention and performance. The purpose of this investigation was to compare isokinetic knee extensor assessment of asymmetry with a more specific countermovement jump (CMJ). Forty-six Brazilian male professional soccer players participated in this study. The maximal power, maximal force and impulse were determined during CMJ and the total work and peak torque at 60, 180, and 300°·s during isokinetic leg extension, separately for each leg. Factor analysis was performed for all investigated variables, and the diagnostic concordance between different criteria was analyzed by McNemar's χ test. The factor analysis showed that the isokinetic and CMJ tests were widely independent methods for the assessment of bilateral differences. Concordance of the diagnostic information could only be found between the maximal force during CMJ and the total work and peak torque at 180 and 300°·s during isokinetic leg extension. Impulse and maximal power during CMJ on a double force platform appear to be appropriate additional variables for the identification of bilateral differences. Therefore, it might be pertinent to perform, in addition to isokinetic assessment, a vertical jump test on a force platform to assure widespread and reliable diagnostic information.

Intermittent Fasting Promotes Weight Loss without Decreasing Performance in Taekwondo.

Intermittent fasting (IF) is commonly used by combat sports athletes for weight loss. However, IF can decrease performance. This study aimed to investigate the effect of IF on total body mass (TBM) and Taekwondo performance. Nine athletes (seven male, two female; 18.4 ± 3.3 years) underwent 4 weeks of 12 h IF. TBM, countermovement jump (CMJ), mean kicks (MK), and total number of kicks (TNK) were compared weekly. Performance was measured in the fed state (FED) and fast state (FAST). Results showed decreased TBM in week 1 (62.20 ± 6.56 kg; p = 0.001) and week 2 (62.38 ± 6.83 kg; p = 0.022) compared to pre-intervention (63.58 ± 6.57 kg), stabilizing in week 3 (62.42 ± 6.12 kg), and no significant change in week 4 (63.36 ± 6.20 kg). CMJ performance in week 1 was lower in FED (35.26 ± 7.15 cm) than FAST (37.36 ± 6.77 cm; p = 0.003), but in week 3, FED (38.24 ± 6.45 cm) was higher than FAST (35.96 ± 5.05 cm; p = 0.047). No significant differences were found in MK and TNK in FSKTmult. RPE, KDI, and HR were similar between FED and FAST (p < 0.05). [LAC] was higher post-test compared to pre-test (p = 0.001), with higher concentrations in FED than FAST (p = 0.020). BG was higher in FED than FAST (p < 0.05) before physical tests. Therefore, IF promotes decreased TBM without decreasing performance.

Oxygen consumption and heart rate during repeated squatting exercises with or without whole-body vibration in the elderly.

Avelar, NCP, Simão, AP, Tossige-Gomes, R, Neves, CDC, Mezencio, B, Szmuchrowski, L, Coimbra, CC, and Lacerda, ACR. Oxygen consumption and heart rate during repeated squatting exercises with or without whole-body vibration in the elderly. J Strength Cond Res 25(12): 3495-3500, 2011-The aim of this study was to investigate whether vibration plus squatting would increase cardiovascular demand to the optimal exercise limits needed for the prescription of cardiovascular training. Oxygen consumption, measured breath by breath by a portable gas analysis system, and heart rate (HR), measured using an HR monitor, were evaluated in 18 elderly individuals, 15 women and 3 men with a mean age of 72 ± 6 years. These variables were measured simultaneously and at the same time points in each subject during rest and randomly during the performance of squatting exercises (8 series of 40 seconds, with 40 seconds of rest between series of performing squats in 3-second cycles with 10-60° of flexion, a total of 5 repetitions for 40 seconds) with or without vibration at a frequency of 40 Hz and amplitude of 4 mm, separated by at least 1 day. Associating whole-body vibration with squatting exercise resulted in an additional increase of around 20% in oxygen consumption and 7.5% in the HR recorded during exercise. However, during squatting exercise with vibration, the increase achieved in oxygen consumption was limited to around 2 metabolic equivalents, and mean HR represented around 56% of the predicted maximum HR for age. The results of this study show that, despite the fact that vibration increased oxygen consumption and HR during the performance of squatting exercise, the minimum standards of intensity for the prescription of physical exercise with the specific objective of improving cardiorespiratory fitness were not achieved. Therefore, a protocol such as that used in the study does not meet the threshold for cardiovascular training prescription.

Time-course of changes in performance, biomechanical, physiological and perceptual responses following resistance training sessions.

This study determined the time-course of recovery after resistance training (RT) sessions and the association between changes in performance with changes in biomechanical, physiological and perceptual parameters. After a 4-week familiarization period, 14 resistance-trained males performed 3 experimental conditions, each one including 2 sessions with a recovery interval of 24, 48 h or 72 h, in a randomized order. RT sessions consisted of 5 sets of 8-10RM on squat and leg press exercises. The resistance was equal for the 2 sessions of each condition and repetitions were performed until concentric failure. Volume load (VL) and first set volume load (FSVL) were compared between sessions. Tests before each session included countermovement jump (CMJ), maximal voluntary isometric contraction (MVIC), creatine kinase (CK) and delayed onset muscle soreness (DOMS). (2 × 3) ANOVA with effect sizes (ES) assessed the time-course of recovery and Kendall test the correlation between variables (α = 0.05). Significant interaction was observed for all variables, except for CK, where a condition main effect occurred. Comparisons between post and pre-intervals showed VL (p = 0.011;ES = -0.90) decreased for 24 h condition, while FSVL remained decreased for 48 h (p = 0.031;ES = -0.63) and DOMS increased (p = 0.001;ES = 3.52). CMJ (p = 0.025;ES = 0.25) and MVIC (p = 0.031;ES = 0.14) performance increased at 72 h. FSVL (r = 0.424), CMJ (r = 0.439), MVIC (r = 0.389) and DOMS (r = -0.327) were significantly correlated with VL (p < 0.05). Time-course of VL showed the necessity of at least 48 h for the reestablishment of performance, though better perceptual responses were evident at 72h. Thus, both recovery intervals may be beneficial after lower-limbs RT until concentric failure, though chronic effects still need to be investigated.

Usefulness of the jump-and-reach test in assessment of vertical jump performance.

The objective was to estimate the reliability and criterion-related validity of the Jump-and-Reach Test for the assessment of squat, countermovement, and drop jump performance of 32 male Brazilian professional volleyball players. Performance of squat, countermovement, and drop jumps with different dropping heights was assessed on the Jump-and-Reach Test and the measurement of flight time, then compared across different jump trials. The very high reliability coefficients of both assessment methods and the lower correlation coefficients between scores on the assessments indicate a very high consistency of each method but only moderate covariation, which means that they measure partly different items. As a consequence, the Jump-and-Reach Test has good ecological validity in situations when reaching height during the flight phase is critical for performance (e.g., basketball and volleyball) but only limited accuracy for the assessment of vertical impulse production with different jump techniques and conditions.

Sustained, prolonged exercise at stable heart rate defined by the deflection point identification method.

Gripp,The objectives of this study were to identify the heart rate deflection point (HRDP) assessed according to the Conconi test method, to evaluate the ability of trained cyclists to pedal for 90 minutes while remaining within a stable heart rate (HR) range determined by identifying the HRDP, and to discuss the motor and physiological parameters recorded during this long-duration exercise. Ten trained men cyclists (VO2max: 64.1 +/- 8.86 mlxkgxmin) had their HRDPs determined. One week later, they performed continuous exercise for 90 minutes on a cycle ergometer at a stable HR sustained within a range comprising the HRDP +/- 5 bpm. Subjects' HR and power output values were registered at each minute. Blood lactate, blood glucose, and body temperature were measured at rest and during exercise. All exercise was performed inside an environmental chamber (temperature of 22 degrees C, relative humidity of 60%). In the first 5 minutes, the participants increased power output to reach the HRDP, and adjustments were required in their physiological parameters to meet this exercise demand. Between the 5th and the 30th minutes, HRDP had already been reached by all participants; nevertheless, all the other physiological and motor parameters were adjusting to this exercise demand. After 30 minutes of exercise, the physiological and motor variables had already adjusted to the new demand and remained stable until the end of exercise (blood lactate was not significantly different from 4 mmolxL). These results suggest the efficacy of the HRDP as an auxiliary method for prescribing and controlling sport training: after the defined HRDP has been reached, the technique confirms maintenance of power output, as well as the other physiological parameters, at threshold levels until the end of exercise.

Effects of mechanical vibration applied in the opposite direction of muscle shortening on maximal isometric strength.

Most studies about human responses to mechanical vibrations involve whole-body vibration and vibration applied perpendicularly to the tendon or muscle. The aim of the present study was to verify the effects of mechanical vibration applied in the opposite direction of muscle shortening on maximal isometric strength of the flexor muscles of the elbow due to neural factors. Conventional isometric training with maximal isometric contractions (MVCs) and isometric training with vibrations were compared. Nineteen untrained males, ages 24 +/- 3.28 years, were divided into 2 training groups. Group 1 performed conventional isometric training and group 2 isometric training with mechanical vibrations (frequency of 8 Hz and amplitude of 6 mm). Both groups executed 12 MVCs with a duration of 6 seconds and 2-minute intervals between the repetitions. The subjects trained 3 times per week for 4 weeks. The strength of the group subjected to vibrations increased significantly by 26 +/- 11% (p < 0.05), whereas the strength of the group with conventional isometric training increased only 10 +/- 5% (p < 0.05). These data suggest that training with vibrations applied in the opposite direction of muscle shortening enhances the mechanism of involuntary control of muscle activity and may improve strength in untrained males. Since these findings were in untrained males, further studies with athletes are necessary in order to generalize the results to athletes' training, although it seems that it would be possible.

Determination of a quantitative parameter to evaluate swimming technique based on the maximal tethered swimming test.

The aim of this study was to propose a new force parameter, associated with swimmers' technique and performance. Twelve swimmers performed five repetitions of 25 m sprint crawl and a tethered swimming test with maximal effort. The parameters calculated were: the mean swimming velocity for crawl sprint, the mean propulsive force of the tethered swimming test as well as an oscillation parameter calculated from force fluctuation. The oscillation parameter evaluates the force variation around the mean force during the tethered test as a measure of swimming technique. Two parameters showed significant correlations with swimming velocity: the mean force during the tethered swimming (r = 0.85) and the product of the mean force square root and the oscillation (r = 0.86). However, the intercept coefficient was significantly different from zero only for the mean force, suggesting that although the correlation coefficient of the parameters was similar, part of the mean velocity magnitude that was not associated with the mean force was associated with the product of the mean force square root and the oscillation. Thus, force fluctuation during tethered swimming can be used as a quantitative index of swimmers' technique.

Indirect sinusoidal vibrations induces an acute increase in explosive strength.

The purpose of this study was to examine the acute effect of indirect vibration on neuromuscular responses and fatigue resistance (electromyographic activity - EMG and force) during isometric exercise. Nineteen healthy men (age=22.4±2.7years; body mass=76.4±12.9kg, height=175±6.7cm) performed isometric elbow flexion exercises in three experimental treatments: only isometric exercise (control - CON); isometric exercise with the addition of sinusoidal vibrations (SVE1; frequency=20Hz, displacement=3.55±0.54mm); and isometric exercise with the addition of sinusoidal vibrations with frequency variation (SVE2; frequency=20±3Hz, displacement=3.6±0.8mm). The peak of the rate of EMG rise (RER) and the root mean square of biceps brachii during the first 200ms (RMS200bic) were significantly higher in SVE1 (RMS200bic, 25.57±11.70%MVC; RER, 266.91±130.16%MVCs-1) than CON (RMS200bic, 19.31±8.19%MVC; RER, 169.15±65.98%MVCs-1). Regarding force, in SVE1, compared to CON, significant increases were observed in peak of rate of force development (CON, 643.96±192.57N/s; SVE1, 845.54±292.84N/s), rate of force development in the first 200ms (CON, 382.92±138,63N/s; SVE1, 501.09±147.46N/s), and impulse in 200ms (CON, 8.56±3.56Ns; SVE1, 11.67±4.45Ns). The addition of indirect sinusoidal vibrations during exercise induced increases in the rate of force development (explosive strength), without affecting the peak force (maximal strength) and the ability to sustain strength production.

Different types of mechanical vibration application on EMG response and strength performance

Abstract Aim: The present study aimed to compare the strength performance and the neuromuscular activity during one maximum repetition test (1RM), and the maximum voluntary isometric contractions (MVIC) performed with whole-body vibration (WBV), local vibration (LV), and no vibration (NV). Methods: The sample consisted of 15 males, experienced in strength training for at least 6 months, which performed all strength tests in the barbell curl exercise across randomized trials on the following conditions: NV, WBV, and LV. During all tests, the normalized root means square values of the electromyographic signals (EMGRMS) of the biceps brachii and brachioradialis were recorded and compared between the conditions. The one-way ANOVAs with repeated measures were used to compare the results of 1RM and MVIC tests and the normalized EMGRMS between the conditions. When necessary, a post hoc Scott-Knott test was used to identify the differences reported in the ANOVAs. The significance level adopted was α < 0.05. Results: The EMGRMS response of the biceps brachii and brachioradialis muscles during the 1RM and MVIC tests presented significantly higher values at LV compared to WBV, and NV (p < 0.001). The 1RM tests, and the MVIC results were similar between conditions (p = 0.9803; p = 0.061, respectively). Conclusion: These results indicate that the application of MV was not sufficient to increase strength performance.

Characterizing the magnitude of vibration imposed by stochastic whole-body vibration platforms used in rehabilitation and training: a preliminary study / Caracterização da magnitude da vibração imposta por plataformas vibratórias estocásticas de corpo inteiro utilizadas em reabilitação e treinamento: estudo preliminar

Abstract The use of devices that produce stochastic whole-body vibration as a resource for rehabilitation and training programs has been founded on the theory of stochastic resonance. However, the prescription of rehabilitation and training programs must be preceded by the verification of imposed-vibration magnitude and of how it can be affected by the presence of an individual on the devices. The aim of this research was to characterize and analyze the effect of an individual's mass on the vibratory stimulus provided by stochastic whole-body vibration (SWBV) devices. The sample consisted of 30 repetitions for each one of the 6 vibration levels of the SWBV device (level 02, 04, 06, 08, 10 and 12), performed in two experimental situations (Without Load; Load [70Kg]; ≈ 35 kg on the right and left surfaces of the platform). For the antero-posterior, latero-lateral, and vertical directions, all variables showed significant differences between treatments, levels and interaction between experimental factors (p<.05), except for the Disp variable between treatments (p=.075). To measure vibration magnitude, a triaxial accelerometer was attached at the center of the board of one of the platform surfaces. Load interferes with parameters of vibration imposed by SWBV platforms, increasing ARMS and APEAK in the latero-lateral and antero-posterior directions, reducing these same parameters in the vertical direction.

Resumo O uso de dispositivos que produzem vibração estocástica de corpo inteiro como recurso para programas de reabilitação e treinamento foi fundamentado na teoria da ressonância estocástica. Entretanto, a prescrição de programas de reabilitação e treinamento deve ser precedida da verificação da magnitude da vibração imposta e de como ela pode ser afetada pela presença de um indivíduo nos dispositivos. O objetivo deste estudo foi caracterizar e analisar o efeito da massa do indivíduo sobre o estímulo vibratório proporcionado por dispositivos de vibração estocástica de corpo inteiro. A amostra consistiu em 30 repetições para cada um dos 6 níveis de vibração de um dispositivo de vibração estocástica de corpo inteiro (nível 02, 04, 06, 08, 10 e 12), realizados em duas situações experimentais (Sem carga e Carga [70Kg], 35 kg nas superfícies direita e esquerda da plataforma). Para medir a magnitude da vibração, um acelerômetro triaxial foi fixado ao centro do assoalho de uma das superfícies da plataforma. Para os eixos ântero-posterior, látero-lateral e vertical, todas as variáveis mostraram diferenças entre tratamentos, níveis e interação entre fatores experimentais (p<.05), exceto para a variável de deslocamento pico - a - pico (Disp) entre tratamentos (p=.075). A carga interfere com parâmetros de vibração impostos sobre as plataformas de vibração estocástica de corpo inteiro, aumentando a aceleração média (ARMS) e de pico (APEAK) nas direções látero-lateral e ântero-posterior, reduzindo estes mesmos parâmetros na direção vertical.

Content Validation of a Catalog of Exercises for Judo.

This study aimed to assess the content validity of a catalog of 76 judo exercises. Two groups of raters comprising 16 judo experts evaluated the following content validity indicators: Clarity of Language, Practical Pertinence, Theoretical Relevance, and the Dimension of each exercise. The results confirmed the content validity of the judo training catalog with indicators showing scores greater than 0.80. These findings suggest that all 76 judo exercises are pertinent, representative of judo training and understandable for judo coaches. Thus, this catalog of judo exercises may help judo coaches in the selection and recording of exercises.

Comparison of tests to evaluate the vertical rebound jump in basketball players / Comparação de testes para avaliação do ressalto vertical em jogadores de basquetebol

ABSTRACT This study aimed to compare the vertical rebound jump performance of basketball players by using Hurdle Jump and Drop Jump tests based on different performance parameters, in addition to investigating whether the height of the hurdles used (barrier and box) are equivalent when the optimal and maximum heights for the tests mentioned are determined. Thirteen players of a male basketball team were included in this study (age 18.77 ±1.78 years old, height 182 ±7.97 m, body mass 76.4 ±9.55 kg, practice time 6.0 ±1.8 years). Data normality and homogeneity were tested by applying Shapiro-Wilk and Levene tests, respectively. The paired t-test was used to compare the means of the results obtained in the tests; the significance level was p ≤ 0.05. The results regarding the comparison of the performance parameters means were the following: the maximum vertical rebound jump and reactive strength index did not show significant differences (p = 0.256 and p = 0.243, respectively); on the other hand, differences were seen for the corresponding obstacle heights. These differences can be attributed to both, individual characteristics of each subject and the specificities of the tests.

RESUMO O objetivo do presente estudo foi comparar o desempenho do ressalto vertical de jogadores de basquetebol por meio dos testes Hurdle Jump e Drop Jump a partir de diferentes parâmetros de desempenho e verificar se a altura dos obstáculos utilizados (barreira e caixote) se equivalem quando forem determinadas a altura ótima e a máxima para os testes mencionados. Participaram do estudo 13 jogadores de uma equipe de basquetebol masculina (idade 18,77 ±1,78 anos, estatura 182 ±7,97 centímetros, massa corporal 76,4 ±9,55 quilogramas, tempo de prática 6,0 ±1,8 anos). A normalidade e a homogeneidade dos dados foram testadas por meio dos testes Shapiro-Wilk e Levene, respectivamente. O Test T pareado foi utilizado na comparação das médias dos resultados obtidos nos testes e o nível de significância foi p≤0,05. Os resultados das comparações das médias dos parâmetros de desempenho: ressalto vertical máximo e índice de força reativa, não apresentaram diferenças significativas (p=0,256 e p=0,243, respectivamente), em contrapartida, foram identificadas diferenças nas alturas dos obstáculos correspondentes. Essas diferenças podem ser atribuídas às características da individualidade de cada sujeito e às especificidades dos testes.

Effects of 12 weeks of dynamic strength training with local vibration.

The purpose of this study was to investigate the chronic effects of dynamic strength training (ST) with local vibration on the maximum strength of elbow flexor muscles. Twenty healthy male untrained volunteers were divided randomly into the following two groups: the conventional training group (CTG) or the vibration training group (VTG). Both groups performed ST for 12 weeks, three times a week. The ST protocol included four sets of 8-10 repetition maximums (RMs) of unilateral elbow flexion exercise. The VTG performed this training protocol with local vibration at a frequency of 30 Hz and amplitude of 6 mm. The mean values of the one repetition maximum (1RM) tests for both groups increased significantly from the pretest week to the fourth week and from the fourth week to the eighth week (CTG: mean 19.02, s = 7.88%, p = 0.01; mean 10.50, s = 6.86%, p = 0.019, respectively; VTG: mean 16.02, s = 8.30%, p = 0.017; mean 12.55, s = 8.76%, p = 0.019, respectively). The increases in the maximal voluntary contraction (MVC) tests were also statistically significant from the pretest week to the fourth week and from the fourth week to the eighth week (CTG: mean 12.32, s = 8.33%, p = 0.004; mean 9.95, s = 5.32%, p = 0.006, respectively; VTG: mean 10.16, s = 11.71%, p = 0.003; mean 10.36, s = 2.96%, p = 0.01, respectively). There was no significant difference between the 1RM and MVC test results in the eighth and twelfth weeks in either group. No significant differences were observed between the groups (p < 0.05). In conclusion, the application of local vibration does not change the chronic effects of dynamic ST in untrained individuals.

[Association of body mass index and aerobic physical fitness with cardiovascular risk factors in children]. / Associação de índice de massa corporal e aptidão física aeróbica com fatores de risco cardiovascular em crianças.

OBJECTIVE: To identify the association between both, body mass index and aerobic fitness, with cardiovascular disease risk factors in children. METHODS: Cross-sectional study, carried out in Itaúna-MG, in 2010, with 290 school children ranging from 6 to 10 years-old of both sexes, randomly selected. Children from schools located in the countryside and those with medical restrctions for physical activity were not included. Blood sample was collected after a 12-hour fasting period. Blood pressure, stature and weight were evaluated in accordance with international standards. The following were considered as cardiovascular risk factors: high blood pressure, high total cholesterol, LDL, triglycerides and insulin levels, and low HDL. The statistical analysis included the Spearman's coefficient and the logistic regression, with cardiovascular risk factors as dependent variables. RESULTS: Significant correlations were found, in both sexes, among body mass index and aerobic fitness with most of the cardiovascular risk factors. Children of both sexes with body mass index in the fourth quartile demonstrated increased chances of having high blood insulin and clustering cardiovascular risk factors. Moreover, girls with aerobic fitness in the first quartile also demonstrated increased chances of having high blood insulin and clustering cardiovascular risk factors. CONCLUSION: The significant associations and the increased chances of having cardiovascular risk factors in children with less aerobic fitness and higher levels of body mass index justify the use of these variables for health monitoring in Pediatrics.

Efeito agudo da aplicação de vibração de corpo inteiro na força muscular de membros superiores / Acute effect of whole body vibration in the upper limbs strength

RESUMO O objetivo desse estudo foi verificar o efeito agudo da aplicação de vibração de corpo inteiro (VCI) sobre o impulso e sobre a força máxima de membros superiores. Vinte voluntários do sexo masculino, treinados, com idade: 23,8 ± 3,3 anos, foram submetidos a 3 sessões (uma sessão de familiarização e duas sessões de intervenção). Em cada uma das sessões de intervenção os voluntários realizaram uma contração voluntária máxima (CVM) de flexores do cotovelo sem aplicação de vibração e duas CVM com adição de vibração. Foram utilizadas 4 frequências de VCI (10, 20, 30 e 40Hz) distribuídas de maneira aleatória nas 4 CVM realizadas com vibração nas duas sessões de coleta. Os resultados encontrados mostraram que a força máxima e o impulso gerados na contração sem vibração foram significativamente maiores do que a força máxima e o impulso gerados durante a contração realizada com aplicação de VCI. Para o treinamento de força, a aplicação de VCI, nas frequências testadas na presente investigação, representou um menor estímulo de treinamento para os membros superiores, uma vez que gerou uma redução na força máxima e no impulso dos músculos flexores do cotovelo.

ABSTRACT The aim of this study was to investigate, from a protocol of maximal isometric contractions of the elbow flexors, the effect of WBV in the maximal force and of impulse in strength-trained individuals. Twenty male volunteers, age: 23.8 ± 3.3 years, performed 3 sessions (one familiarization session and two intervention session). The sessions were composed by 3 MVC of the elbows flexor muscles with 5 minute of rest between them. The first CVM was performed without vibration and the others, applying aleatory WBV with 10, 20, 30, 40Hz, and amplitude of 6mm. The results showed that the maximal force and of impulse obtained during the MVC without vibration was significantly higher than the maximal force and of impulse recorded during the application of WBV. For strength training, the application of WBV, in the adopted frequencies, was not able to generate sufficient stimulus to induce acute adaptations in muscle strength of upper limbs.

Criteria validity of the Netherlands physical activity questionnaire for children / Validade critério do Netherland Physical Activity Questionnaire para crianças

Abstract Physical activity measurement with accuracy and precision is extremely important in establishing the dose-response relationship between levels of physical activity and the different outcome possibilities. Subjective methods of measurement, such as proxy-reports have been used as a possibility to check physical activity in children. The aim of this study was to test the Netherlands Physical Activity Questionnaire (NPAQ), valid for Brazilian schoolchildren using physical aerobic fitness as a criterion. The study included 290 children aged 6-10 years from public schools of Itaúna/MG. NPAQ was applied to parents or guardians and children were tested using the Luc Léger test. NPAQ had mean score of 25 for children (25 for boys and 24 for girls) and VO2max was 50.8 ml/kg/min for children (52.6 and 50.2 ml/kg/min for boys and girls, respectively). The Spearmam correlation test showed significant correlation (rsho = 0.146; p = 0.013) between NPAQ and VO2max, but the correlation is weak (Kappa -0.14). The results showed that NPAQ presented poor construct validity for physical activity measurement in a Brazilian schoolchildren sample, based on aerobic physical fitness criteria.

Resumo A mensuração da atividade física com acurácia e precisão é de extrema importância no estabelecimento da relação de dose-resposta entre os níveis de atividade física e as diversas possibilidades de desfecho, sendo um desafio de extrema complexidade. A utilização de métodos subjetivos de mensuração, como os instrumentos proxy-reports, é uma possibilidade de verificação de atividade física em crianças. O objetivo deste estudo foi testar a validade do Netherland Physical Activity Questionnaire (NPAQ) em escolares brasileiros tendo como medida critério a aptidão física aeróbica. Participaram deste estudo 290 crianças de seis a 10 anos de idade, matriculados em escolas públicas do município de Itaúna/MG. Foi aplicado aos responsáveis o NPAQ e as crianças realizaram o teste de Luc Léger. O NPAQ apresentou um escore mediano de 25 para as crianças (25 meninos e 24 meninas) e o VO2máx foi de 50,8 ml/kg/min para as crianças (52,6 e 50,2 ml/kg/min para meninos e meninas, respectivamente). O NPAQ e o VO2máx apresentaram no teste de correlação simples de Spearmam rsho = 0,146 (p = 0,013) correlação significativa, porém fraca (Kappa -0.14). Os resultados permitem concluir que o NPAQ apresentou fraca validade de constructo para mensuração de atividade física em uma amostra de escolares brasileiros, tendo como medida critério a aptidão física aeróbica.