Sex-Specific Accumulated Oxygen Deficit During Short- and Middle-Distance Swimming Performance in Competitive Youth Athletes.

INTRODUCTION: Since sex-specific accumulated oxygen deficit (AOD) during high-intensity swimming remains unstudied, this study aimed to assess AOD during 50, 100, and 200 m front-crawl performances to compare the responses between sexes and analyse the effect of lean body mass (LBM). METHODS: Twenty swimmers (16.2 ± 2.8 years, 61.6 ± 7.8 kg, and 48.8 ± 11.2 kg LBM-50% males) performed 50, 100, and 200 m to determine accumulated oxygen uptake (V̇O2Ac). The swimmers also performed an incremental test from which five submaximal steps were selected to estimate the oxygen demand (V̇O2demand) from the V̇O2 versus velocity adjustment. V̇O2 was sampled using a gas analyser coupled with a respiratory snorkel. AOD was the difference between V̇O2demand and V̇O2Ac, and LBM (i.e. lean mass not including bone mineral content) was assessed by dual-energy X-ray absorptiometry (DXA). RESULTS: A two-way ANOVA evidenced an AOD increase with distance for both sexes: 19.7 ± 2.5 versus 24.9 ± 5.5, 29.8 ± 8.0 versus 36.5 ± 5.8, and 41.5 ± 9.4 versus 5.2 ± 11.9 ml × kg-1, respectively, for 50, 100, and 200 m (with highest values for females, P < 0.01). Inverse correlations were observed between LBM and AOD for 50, 100, and 200 m (r = - 0.60, - 0.38 and - 0.49, P < 0.05). AOD values at 10 and 30 s elapsed times in each trial decreased with distance for both sexes, with values differing when female swimmers were compared to males in the 200 m trial (at 10 s: 2.6 ± 0.6 vs. 3.4 ± 0.6; and at 30 s: 7.9 ± 1.7 vs. 10.0 ± 1.8 ml × kg-1, P < 0.05). CONCLUSION: LBM differences between sexes influenced AOD values during each trial, suggesting that reduced muscle mass in female swimmers plays a role on the higher AOD (i.e. anaerobic energy) demand than males while performing supramaximal trials.

The reliability of back-extrapolation in estimating V ˙ O 2 p e a k in different swimming performances at the severe-intensity domain.

The amount of anerobic energy released during exercise might modify the initial phase of oxygen recovery (fast-O2debt) post-exercise. Therefore, the present study aimed to analyze the reliability of peak oxygen uptake ( V ˙ O 2 p e a k ) estimate by back-extrapolation ( B E - V ˙ O 2 p e a k ) under different swimming conditions in the severe-intensity domain, verifying how the alterations of the V ˙ O 2 recovery profile and anerobic energy demand might affect B E - V ˙ O 2 p e a k values. Twenty swimmers (16.7 ± 2.4 years, 173.5 ± 10.2 cm, and 66.4 ± 10.6 kg) performed an incremental intermittent step protocol (IIST: 6 × 250 plus 1 × 200 m, IIST_v200m) for the assessment of V ˙ O 2 p e a k . The V ˙ O 2 off-kinetics used a bi-exponential model to discriminate primary amplitude, time delay, and time constant (A1off, TD1off, and τoff) for assessment of fast-O2debt post IIST_v200m, 200-m single-trial (v200 m), and rest-to-work transition at 90% delta (v90%Δ) tests. The linear regression estimated B E - V ˙ O 2 p e a k and the rate of V ˙ O 2 recovery (BE-slope) post each swimming performance. The ANOVA (Sidak as post hoc) compared V ˙ O 2 p e a k to the estimates of B E - V ˙ O 2 p e a k in v200 m, IIST_v200 m, and v90%Δ, and the coefficient of dispersion (R2) analyzed the association between tests. The values of V ˙ O 2 p e a k during IIST did not differ from B E - V ˙ O 2 p e a k in v200 m, IIST_v200 m, and v90%Δ (55.7 ± 7.1 vs. 53.7 ± 8.2 vs. 56.3 ± 8.2 vs. 54.1 ± 9.1 ml kg-1 min-1, p > 0.05, respectively). However, the V ˙ O 2 p e a k variance is moderately explained by B E - V ˙ O 2 p e a k only in IIST_v200 m and v90%Δ (RAdj 2 = 0.44 and RAdj 2 = 0.43, p < 0.01). The TD1off and τoff responses post IIST_v200 m were considerably lower than those in both v200 m (6.1 ± 3.8 and 33.0 ± 9.5 s vs. 10.9 ± 3.5 and 47.7 ± 7.9 s; p < 0.05) and v90%Δ ( 10.1 ± 3.8 and 44.3 ± 6.3 s, p < 0.05). The BE-slope post IIST_v200m was faster than in v200 m and v90%Δ (-47.9 ± 14.6 vs. -33.0 ± 10.4 vs. -33.6 ± 13.8 ml kg-1, p < 0.01), and the total anerobic (AnaerTotal) demand was lower in IIST_v200 m (37.4 ± 9.4 ml kg-1) than in 200 m and 90%Δ (51.4 ± 9.4 and 46.2 ± 7.7 ml kg-1, p < 0.01). Finally, the τ1off was related to AnaerTotal in IIST_v200m, v200 m, and v90%Δ (r = 0.64, r = 0.61, and r = 0.64, p < 0.01). The initial phase of the V ˙ O 2 recovery profile provided different (although reliable) conditions for the estimate of V ˙ O 2 p e a k with BE procedures, which accounted for the moderate effect of anerobic release on V ˙ O 2 off-kinetics, but compromised exceptionally the V ˙ O 2 p e a k estimate in the 200-m single trial.

Influence of Angiotensin-Converting Enzyme Inhibitors (ACEi) on Angiogenesis Induced by Physical Exercise / Influência dos Inibidores da Enzima Conversora de Angiotensina (iECA) Sobre a Angiogênese Induzida pelo Exercício Físico

Abstract Angiotensin-converting enzyme inhibitors (ACEi) are used to reduce blood pressure and vascular resistance by modulating the ACE activity responsible for the angiotensin II formation. However, different ACEi seem to influence exercise-induced angiogenesis. The objective of this review was to investigate the effects of different ACEi on vessel growth in skeletal muscle induced by exercise training. The present study is characterized by a narrative literature review design, the databases of Scielo, Google Scholar and PubMed were consulted. There are different groups of ACEi , sulfhydryl group such as captopril and a carboxyl group such as perindiporil and enalapril that can influence their effects on ACE activity. It is already known that exercise promotes the increase of vessels from vessels already existing in the skeletal musculature, a process known as angiogenesis and contributes to the blood pressure reduction (BP). Although these different responses are still scarce, vessel endothelial growth factor (VEFG) and nitric oxide (NO) may participate. Thus, the use of different ACEi can influences the angiogenesis responses induced by exercise, being one of the important mechanisms for BP reduction. The choice of ACEi group should be carefully analyzed for hypertensive individuals who practice physical exercise. (AU)

Resumo Os inibidores da enzima conversora de angiotensina (iECA) são utilizados para redução da pressão arterial e resistência vascular modulando a atividade da ECA responsável pela formação da angiotensina II. Entretanto, diferentes iECAs parecem influenciar a angiogênese induzida pelo exercício físico. Desta maneira objetivo desta revisão foi investigar os efeitos de diferentes iECA sobre o crescimento de vasos no musculo esquelético induzido pelo exercício físico. O presente estudo caracteriza-se um delineamento de revisão de literatura narrativa, foram consultadas as bases de dados do Scielo, Google acadêmico e PubMed. Existem grupos distintos dos iECAs, grupo sulfidrila como o captopril e o grupo carboxila como o perindiporil e grupo que pode influenciar seus efeitos sobre a atividade da ECA. Já é sabido que O exrcício promove o aumento de vasos a partir de vasos já existentes na musculatura esquelética, processo conhecido como angiogênese e colabora para redução da pressão arterial (PA). Entretanto os iECAs parecem influenciar esta resposta do aumento da densidade capilar no músculo esquelético. Embora ainda sejam escassos estas diferentes respostas podem ter as participações do fator de crescimento endotelial de vasos (VEFG) e o óxido nítrico (NO). Desta maneira o uso dos grupos do iECAs podem influenciar as resposta da angiogênese induzido pelo exercício sendo um dos mecanismos importantes pela redução da PA. A escolha do grupo de iECA deve ser analisada com cautela para indivíduoS hipertensos que praticam exercício físico. (AU)

Energetics contribution during no-gi Brazilian jiu jitsu sparring and its association with regional body composition.

We used measurements of metabolic perturbation obtained after sparring to estimate energetics contribution during no-gi Brazilian jiu-jitsu. Ten advanced grapplers performed two six-minute sparring bouts separated by 24 hours. Kinetics of recovery rate of oxygen uptake was modelled and post-combat-sparring blood-lactate concentration measured to estimate oxygen equivalents for phospholytic and glycolytic components of anaerobic energetics, respectively. Linear regression was used to estimate end-combat-sparring rate of oxygen uptake. Regional and whole-body composition were assessed using dual X-ray absorptiometry with associations between these measurements and energy turnover explored using Pearson's correlation coefficient (significance, P < 0.05). Estimated oxygen equivalents for phospholytic and glycolytic contributions to anaerobic metabolism were 16.9 ± 8.4 (~28%) and 44.6 ± 13.5 (~72%) mL∙kg-1, respectively. Estimated end-exercise rate of oxygen uptake was 44.2 ± 7.0 mL∙kg-1∙min-1. Trunk lean mass was positively correlated with both total anaerobic and glycolytic-specific energetics (total, R = 0.645, p = 0.044; glycolytic, R = 0.692, p = 0.027) and negatively correlated with end-exercise rate of oxygen uptake (R = -0.650, p = 0.042). There were no correlations for any measurement of body composition and phospholytic-specific energetics. Six minutes of no-gi Brazilian jiu-jitsu sparring involves high relative contribution from the glycolytic component to total anaerobic energy provision and the link between this energetics profile and trunk lean mass is consistent with the predominance of ground-based combat that is unique for this combat sport. Training programs for Brazilian jiu-jitsu practitioners should be designed with consideration given to these specific energetics characteristics.

Physiological Responses During High-Intensity Interval Training in Young Swimmers.

This study analyzed whether 100- and 200-m interval training (IT) in swimming differed regarding temporal, perceptual, and physiological responses. The IT was performed at maximal aerobic velocity (MAV) until exhaustion and time spent near to maximalVO2 peak oxygen uptake (⩒O2peak), total time limit (tLim), peak blood lactate [La-] peak, ⩒O2 kinetics (⩒O2K), and rate of perceived exertion (RPE) were compared between protocols. Twelve swimmers (seven males 16.1 ± 1.1 and five females 14.2 ± 1 years) completed a discontinuous incremental step test for the second ventilatory threshold (VT2), ⩒O2peak, and MAV assessment. The swimmers subsequently completed two IT protocols at MAV with 100- and 200-m bouts to determine the maximal ⩒O2 (peak-⩒O2) and time spent ≥VT2, 90, and 95% of ⩒O2peak for the entire protocols (IT100 and IT200) and during the first 800-m of each protocol (IT8x100 and IT4x200). A portable apparatus (K4b2) sampled gas exchange through a snorkel and an underwater led signal controlled the velocity. RPE was also recorded. The Peak-⩒O2 attained during IT8x100 and IT4x200 (57.3 ± 4.9 vs. 57.2 ± 4.6 ml·kg-1·min-1) were not different between protocols (p = 0.98) nor to ⩒O2peak (59.2 ± 4.2 ml·kg-1·min-1, p = 0.37). The time constant of ⩒O2K (24.9 ± 8.4 vs. 25.1 ± 6.3-s, p = 0.67) and [La-] peak (7.9 ± 3.4 and 8.7 ± 1.5 mmol·L-1, p = 0.15) also did not differ between IT100 and IT200. The time spent ≥VT2, 90, and 95%⩒O2peak were also not different between IT8x100 and IT4x200 (p = 0.93, 0.63, and 1.00, respectively). The RPE for IT8x100 was lower than that for IT4x200 (7.62 ± 2 vs. 9.5 ± 0.7, p = 0.01). Both protocols are considered suitable for aerobic power enhancement, since ⩒O2peak was attained with similar ⩒O2K and sustained with no differences in tLim. However, the fact that only the RPE differed between the IT protocols suggested that coaches should consider that nx100-m/15-s is perceived as less difficult to perform compared with nx200-m/30-s for the first 800-m when managing the best strategy to be implemented for aerobic power training.

Spatial index relating urban environment to health lifestyle and obesity risk in men and women from different age groups.

The challenge in the search for relationships between urban space, physical mobility, and health status, is detecting indicators able to link the environment with healthy life habits. Therefore, the objective was to design an urban index for the identification of urban environment propensity for physical activity (PA) and to determine how it relates to lifestyle and anthropometric parametrization of obesity. Participants (N = 318-60.4% women and 39.6% men) were recruited from a mid-sized city with epidemiology and morbidity rates below the average for the mid-west region of Brazil. Body mass index (BMI) was measured and a questionnaire was applied to gather information about PA and life habits. The spatial urban health index (SUHI) was designed in a geographic information system using data from demographic, environmental and urban physical features. The relationship between BMI and PA was verified with multiple linear regression, controlled for SUHI levels. Regarding the BMI of the population, 69.5% were classified in the eutrophic or overweight ranges, with no effect of gender and age. The SUHI classified 63.7% of the urban area favorable to PA. The PA routine was adequate (≥3 sessions with ≥1 h each) for ~80% of the population, as well as healthy habits such as non smoking (~94%) and non alcohol abuse (~55%). The SUHI strengthens the relationships of BMI to weekly frequency (r = -0.68; t = -9.4; p<0.001) and session duration (r = -0.66; t = -2.8; p<0.001) for the whole group by improving the explanatory coefficient in ~25% (R2Adj = 0.61 to R2Adj = 0.85). The SUHI indicated that the urban environment is able to promote healthy life habits by diminishing the "obesogenic" features of the city when physical structures are planned to facilitate PA, whatever the gender and age group.

Women's femoral mass content correlates to muscle strength independently of lean body mass / A massa femoral das mulheres relaciona-se com a força muscular independentemente da massa magra / La masa femoral de las mujeres se relaciona con la fuerza muscular, independiente de la masa magra

ABSTRACT Introduction There is limited consensus regarding the recommendation of the most effective form of exercise for bone integrity, despite the fact that weight training exercise promotes an increase in muscle mass and strength as recurrent responses. However, strength variations in women do not depend on muscle mass development as they do in men, but strength enhancement has shown the potential to alter bone mineral content (BMC) for both sexes. Objective This study analyzed the potential of muscle strength, as well as that of whole-body and regional body composition, to associate femoral BMC in young women. Methods Fifteen female college students (aged 24.9 ± 7.2 years) were assessed for regional and whole-body composition using dual-energy X-ray absorptiometry (DXA). Maximum muscle strength was assessed by the one-repetition maximum (1RM) test in the following exercises: bench press (BP), lat pulldown (LP), knee flexion (KF), knee extension (KE) and 45° leg press (45LP). Linear regression analyzed BMC relationships with regional composition and 1RM values. Dispersion and error measures (R 2 aj and SEE), were tested, defining p ≤0.05. Results Among body composition variables, only total lean body mass was associated with femoral BMC values (R 2 aj = 0.37, SEE = 21.3 g). Regarding strength values, 1RM presented determination potential on femoral BMC in the CE exercise (R 2 aj = 0.46, SEE = 21.3 g). Conclusions Muscle strength aptitude in exercises for femoral regions is relevant to the femoral mineralization status, having associative potential that is similar to and independent of whole-body lean mass. Therefore, training routines to increase muscle strength in the femoral region are recommended. In addition, increasing muscle strength in different parts of the body may augment bone remodeling stimulus, since it can effectively alter total whole-body lean mass. Level of Evidence II; Development of diagnostic criteria in consecutive patients (with universally applied reference ''gold'' standard).

RESUMO Introdução Há pouco consenso em relação à recomendação sobre o exercício mais efetivo para a integridade óssea, apesar de o exercício com peso apresentar como respostas recorrentes o aumento da força e da massa muscular. Contudo, entre mulheres as variações da força não dependem do desenvolvimento da massa muscular, tanto quanto em homens, mas o aumento da força tem evidenciado potencial para alterar o conteúdo mineral ósseo (BMC) em ambos os sexos. Objetivos O presente estudo analisou o potencial da força muscular, assim como da composição regional e corporal, ao associar o BMC do fêmur entre as mulheres jovens. Métodos Quinze universitárias (24,9 ± 7,2 anos) foram avaliadas quanto à composição regional e corporal por meio de absorciometria por duplo feixe de raios-X (DXA). A força muscular máxima foi avaliada por uma repetição máxima (1RM) nos exercícios de supino-reto (SR), puxada-alta (PA), flexão do joelho (FJ), extensão do joelho (EJ) e leg press 45° (LP45). A regressão linear analisou as relações de BMC com a composição regional e os valores de 1RM. Foram testadas medidas de dispersão e erro (R2aj e EPE), definindo p≤0,05. Resultados Entre as variáveis da composição corporal, apenas a massa magra corporal total associou-se aos valores de BMC femoral (R2aj=0,37, EPE=21,3 g). Em relação aos valores de força, 1RM no exercício de CE apresentou potencial de determinação sobre o BMC femoral (R2aj=0,46, EPE=21,3 g). Conclusão A aptidão da força muscular em exercícios para regiões próximas ao fêmur é relevante para o estado de mineralização femoral, com potencial associativo similar e independente à massa magra corporal. Recomenda-se, portanto, rotinas de treinamento para aumentar a força muscular da região próxima ao fêmur; adicionalmente, o aumento da força para diferentes regiões corporais pode potencializar o estímulo sobre a remodelação óssea, uma vez que é efetivo na alteração da massa magra corporal total. Nível de Evidência II; Desenvolvimento de critérios diagnósticos em pacientes consecutivos (com padrão de referência "ouro" aplicado).

RESUMEN Introducción Hay poco consenso con relación a la recomendación sobre el ejercicio más efectivo para la integridad ósea, a pesar de que el ejercicio con peso presenta como respuestas recurrentes el aumento de la fuerza y de la masa muscular. Sin embargo, entre mujeres las variaciones de la fuerza no dependen del desarrollo de la masa muscular, tanto como en hombres, sino que el aumento de la fuerza ha evidenciado potencial para alterar el contenido mineral óseo (BMC) en ambos sexos. Objetivos El presente estudio analizó el potencial de la fuerza muscular, así como de la composición regional y corporal, al asociar el BMC del fémur entre las mujeres jóvenes. Métodos Quince universitarias (24,9 ± 7,2 años) fueron evaluadas cuanto a la composición regional y corporal por medio de absorciometría de rayos X de doble energía (DXA). La fuerza muscular máxima fue evaluada por una repetición máxima (1RM) en los ejercicios de press de banca recto (PBR), remada alta (RA), flexión de rodilla (FR), extensión de rodilla (ER) y leg press 45° (LP45). La regresión lineal analizó las relaciones de BMC con la composición regional y los valores de 1RM. Fueron probadas medidas de dispersión y error (R2aj y EEE), definiendo p≤0,05. Resultados Entre las variables de la composición corporal, sólo la masa magra corporal total se asoció a los valores de BMC femoral (R2aj=0,37, EEE=21,3 g). Con relación a los valores de fuerza, 1RM en el ejercicio de CE presentó potencial de determinación sobre el BMC femoral (R2aj=0,46, EEE=21,3 g). Conclusión La aptitud de la fuerza muscular en ejercicios para regiones próximas al fémur es relevante para el estado de mineralización femoral, con potencial asociativo similar e independiente a la masa magra corporal. Se recomiendan, por lo tanto, rutinas de entrenamiento para aumentar la fuerza muscular de la región próxima al fémur; adicionalmente, el aumento de la fuerza para diferentes regiones corporales puede potencializar el estímulo sobre la remodelación ósea, dado que es efectivo en la alteración de la masa magra corporal total. Nivel de Evidencia II; Desarrollo de criterios diagnósticos en pacientes consecutivos (con patrón de referencia "oro" aplicado).

Assessment of critical velocity in track and treadmill: physiological profiles and relationship with 3000-meter performance / Avaliação da velocidade crítica de corrida em pista e esteira: perfis fisiológicos e relações com o desempenho em 3000 metros

The present study aiming to verify the interference of different conditions (treadmill vs. track) on critical velocity (CV) values, as well as on the correlation to the 3000-meter performance (v3000m), and thus infer about the specificity of each values as training parameter for this distance. Seven runners (15.3±1.4 years) were submitted to a maximal progressive test (1.0 km×h-1 increments per minute until exhaustion) to assess V̇O2max and maximal aerobic velocity (vV̇O2max). Subsequently, CV was estimated from three running performances at each test condition, with exercise intensities adjusted for different time limits (tLim) at 900, 2100 and 3300 meters in track or at 90, 95 and 115% of vV̇O2max in treadmill. From linear adjustments, using stepwise method, CV was assessed on treadmill (CVTREADMILL) and track (CVTRACK), and both compared by the Mann-Whitney test. The sample-adjusted dispersion coefficient (R2adj) analyzed the variance of v3000m with CVTRACK, CVTREADMILL and vV̇O2max. In all analyses, significance was set at P≤0.05. In progressive test, V̇O2max reached 54.2±5.2 mLO2×kg-1×min-1 and vV̇O2max reached 16.8±1.9 km×h-1. No differences were observed between CVTREADMILL and CVTRACK (14.0±1.8 vs. 12.3±3.2 km×h-1, P=0.46). Correlations were observed for v3000m with CVTREADMILL (R2adj ~0.94), CVTRACK (R2adj ~0.99) and vV̇O2max (R2adj ~0.90), all showing P=0.001. It could be concluded that no influence was observe on the ability to achieve identical CV values from different assessment conditions. The correlation to the v3000 meters suggested better specificity of CVTRACK than CVTREADMILL for training prescription and performance control.

O presente estudo averiguou se as diferenças nas circunstâncias (esteira vs. pista) de avaliação da velocidade crítica (VC) interferem no valor e na relação com a desempenho em 3000 metros (v3000m) e, assim, indicar a especificidade de cada valor como parâmetro de treinamento para esta distância. Sete corredores (15,3±1,4 anos) submeteram-se a um teste progressivo máximo (incrementos de 1,0 km×h-1×min-1, até a exaustão) para avaliação do V̇O2max e velocidade aeróbia máxima (vV̇O2max). A seguir, a VC foi estimada a partir do desempenho de corrida em três diferentes intensidades do exercício, em cada ambiente de avaliação, registrando-se o tempo-limite (tLim) nas distâncias de 900, 2100 e 3300 metros na pista, e à 90, 95 e 115% vV̇O2max em esteira. Ajustes lineares, pelo método "stepwise", forneceram os parâmetros VC em esteira (VCESTEIRA) e pista (VCPISTA), que foram comparados pelo teste de Mann-Whitney. O coeficiente de dispersão ajustado à amostra (R2aj) averiguou a variância de v3000m com VCPISTA, VCESTEIRA e vV̇O2max. Em todas as análises adotou-se .≤0,05. No teste progressivo, o V̇O2max atingiu 54,2±5,2 mLO2∙kg-1∙min-1 e a vV̇O2max foi 16,8±1,9 km×h-1. Não se observaram diferenças entre VCESTEIRA e VCPISTA (14,0±1,8 vs. 12,3±3,2 km∙h-1, P=0,46). Houveram correlações entre v3000m com VCESTEIRA (R2aj ~0,94), VCPISTA (R2aj~0,99) e vV̇O2max (R2aj ~0,90), todas com P=0,001. Conclui-se que o contexto de avaliação não interfere na consistência do valor de VC. Porém, quanto à relação com v3000 metros, a VCPISTA apresenta melhor especificidade, tornando-a mais autêntica que VCESTEIRA para a prescrição do treino e monitoramento do desempenho.

Muscular strength and regional lean mass influence bone mineral health among young females / Força muscular e massa magra regional influenciam a saúde mineral óssea entre jovens mulheres / Fuerza muscular y masa magra influencian la salud mineral ósea entre jóvenes mujeres

ABSTRACT Introduction: Strength training is able to stimulate bone tissue metabolism by increasing mechanical stress on the skeletal system. However, the direct relationship is not yet well established among younger women, since it is necessary to describe which strength enhancement level is able to produce effective changes in bone integrity. Objectives: This study analyzed the influence of muscle strength on bone mineral content (BMC) and bone mineral density (BMD) among female college students. Methods: Fifteen women (24.9 ± 7.2 years) were assessed for regional and whole-body composition by dual-energy X-ray absorptiometry (DXA). The one-repetition maximum (1-RM) tests were assessed on flat bench press (BP), lat pulldown (LPD), leg curl (LC), knee extension (KE), and 45 degree leg press (45LP). Linear regression analyzed the relationships of BMC/BMD with regional composition and 1-RM test values. Measures of dispersion and error (R2 adj and SEE) were tested, defining a p-value of 0.05. Results: The mean value of whole-body BMC was 1925.6 ± 240.4 g and the BMD was 1.03 ± 0.07 g/cm2. Lean mass (LM) was related to BMC (R2 adj = 0.86, p<0.01, and SEE = 35.6 g) and BMD (R2 adj = 0.46, p<0.01, SEE = 0.13 g) in the lower limbs (LL). The 1-RM tests in BP were associated with BMC and BMD (R2 adj = 0.52, p<0.01, SEE = 21.4 g, and R2 adj = 0.68, p<0.01, SEE = 0.05 g/cm2, respectively) in the upper limbs, while the 1-RM tests in KE were related to BMC and BMD (R2 adj = 0.56, p<0.01. SEE = 62.6 g, and R2 adj = 0.58, p<0.01, SEE = 0.11 g/cm2, respectively) in the lower limbs. Conclusions: Hence, the 1-RM tests for multi-joint exercises are relevant to the regional BMC/BMD, reinforcing the need to include resistance exercises in training routines with the purpose of improving muscular strength and regional lean mass, thereby ensuring a healthy bone mineral mass. Level of Evidence II; Development of diagnostic criteria in consecutive patients (with applied reference ''gold'' standard).

RESUMO Introdução: O treinamento de força é capaz de estimular o metabolismo do tecido ósseo, aumentando o estresse mecânico sobre o sistema esquelético. No entanto, a relação direta ainda não está bem estabelecida entre as mulheres mais jovens, uma vez que deve ser descrito qual nível de aprimoramento da força é capaz de induzir mudanças efetivas na integridade óssea. Objetivos: Este estudo analisou a influência da força muscular sobre o conteúdo mineral ósseo (BMC) e a densidade mineral óssea (BMD) entre estudantes universitárias. Métodos: Quinze mulheres (24,9±7,2 anos) foram avaliadas quanto à composição regional e corporal através de absorciometria com raios-X de dupla energia (DEXA). Os testes de repetição máxima (1RM) foram avaliados no supino reto (SR), puxada alta (PA), flexão do joelho (FJ), extensão do joelho (EJ) e leg press 45° (LP45). A regressão linear analisou as relações de BMC/BMD com a composição regional e valores dos testes 1RM. As medidas de dispersão e erro (R2 aj e SEE) foram testadas definindo p ≤0,05. Resultados: O valor médio do BMC corporal foi de 1925,6 ± 240,4 g e BMD de 1,03 ± 0,07 g/cm2. A massa magra (MM) foi relacionada ao BMC (R2 aj=0,86, p<0,01 e SEE=35,6 g) e à BMD (R2 aj=0,46, p<0,01, SEE = 0,13 g/cm2) nos membros inferiores (MI). Os testes 1RM no SR associaram-se com o BMC e à BMD (R2 aj=0,52, p<0,01, SEE=21,4 g, e R2 aj=0,68, p<0,01, SEE=0,05 g/cm2, respectivamente) nos membros superiores, assim como os testes 1RM na EJ relacionaram-se ao BMC e à BMD (R2 aj=0,56, p<0,01, SEE=62,6 g, e R2 aj=0,58, p<0,01, SEE=0,11 g/cm2, respectivamente) nos MI. Conclusões: Dessa forma, os testes 1RM para exercícios multiarticulares são relevantes para o BMC/BMD regional, intensificando a necessidade de incluir exercícios resistivos nas rotinas de treinamento com o propósito de melhorar a força muscular e a massa magra regional e, portanto, assegurar uma massa mineral óssea saudável. Nível de Evidência II; Desenvolvimento de critérios diagnósticos em pacientes consecutivos (com padrão de referência "ouro" aplicado).

RESUMEN Introducción: El entrenamiento de fuerza es capaz de estimular el metabolismo del tejido óseo, aumentando el estrés mecánico sobre el sistema esquelético. Sin embargo, la relación directa aún no está bien establecida entre las mujeres más jóvenes, dado que debe ser descrito qué nivel de mejora de la fuerza es capaz de inducir cambios efectivos en la integridad ósea. Objetivos: Este estudio analizó la influencia de la fuerza muscular sobre el contenido mineral óseo (BMC) y la densidad mineral ósea (BMD) entre estudiantes universitarias. Métodos: Quince mujeres (24,9±7,2 años) fueron evaluadas cuanto a la composición regional y corporal a través de absorciometría con rayos-X de doble energía (DEXA). Los tests de repetición máxima (1RM) fueron evaluados en el supino recto (SR), dominada alta (DA), flexión de la rodilla (FR), extensión de la rodilla (ER) y leg press 45° (LP45). La regresión lineal analizó las relaciones de BMC/BMD con la composición regional y valores de los tests 1RM. Las medidas de dispersión y error (R2 aj y SEE) fueron probadas definiendo p ≤0,05. Resultados: El valor promedio del BMC corporal fue de 1925,6 ± 240,4 g y BMD de 1,03 ± 0,07 g/cm2. La masa magra (MM) fue relacionada al BMC (R2 aj=0,86, p<0,01 y SEE=35,6 g) y a la BMD (R2 aj=0,46, p<0,01, SEE = 0,13 g/cm2) en los miembros inferiores (MI). Los tests 1RM en el SR se asociaron con el BMC y a la BMD (R2 aj=0,52, p<0,01, SEE=21,4 g, y R2 aj=0,68, p<0,01, SEE=0,05 g/cm2, respectivamente) en los miembros superiores, así como los testes 1RM en la ER se relacionaron al BMC y a la BMD (R2 aj=0,56, p<0,01, SEE=62,6 g, y R2 aj=0,58, p<0,01, SEE=0,11 g/cm2, respectivamente) en los MI. Conclusiones: De esa forma, los tests 1RM para ejercicios multiarticulares son relevantes para el BMC/BMD regional, intensificando la necesidad de incluir ejercicios resistivos en las rutinas de entrenamiento con el propósito de mejorar la fuerza muscular y la masa magra regional y, por lo tanto, asegurar una masa mineral ósea saludable. Nivel de Evidencia II; Desarrollo de criterios diagnósticos en pacientes consecutivos (con estándar de referencia "oro" aplicado).

Muscle strength and regional lean body mass influence on mineral bone health in young male adults.

The relationship between muscle strength and bone mineral content (BMC) and bone mineral density (BMD) is supposed from the assumption of the mechanical stress influence on bone tissue metabolism. However, the direct relationship is not well established in younger men, since the enhancement of force able to produce effective changes in bone health, still needs to be further studied. This study aimed to analyze the influence of muscle strength on BMC and BMD in undergraduate students. Thirty six men (24.9 ± 8.6 y/o) were evaluated for regional and whole-body composition by dual energy X-ray absorptiometry (DXA). One repetition maximum tests (1RM) were assessed on flat bench-press (BP), lat-pull down (LPD), leg-curl (LC), knee extension (KE), and leg-press 45° (LP45) exercises. Linear regression modelled the relationships of BMD and BMC to the regional body composition and 1RM values. Measurements of dispersion and error (R2adj and standard error of estimate (SEE)) were tested, setting ρ at ≤0.05. The BMD mean value for whole-body was 1.12±0.09 g/cm2 and BMC attained 2477.9 ± 379.2 g. The regional lean mass (LM) in upper-limbs (UL) (= 6.80±1.21 kg) was related to BMC and BMD for UL (R2adj = 0.74, p<0.01, SEE = 31.0 g and R2adj = 0.63, SEE = 0.08 g/cm2), and LM in lower-limbs (LL) (= 19.13±2.50 kg) related to BMC and BMD for LL (R2adj = 0.68, p<0,01, SEE = 99.3 g and R2adj = 0.50, SEE = 0.20 g/cm2). The 1RM in BP was related to BMD (R2adj = 0.51, SEE = 0.09 g/cm2), which was the strongest relationship among values of 1RM for men; but, 1RM on LPD was related to BMC (R2adj = 0.47, p<0.01, SEE = 44.6 g), and LC was related to both BMC (R2adj = 0.36, p<0.01, SEE = 142.0 g) and BMD (R2adj = 0.29, p<0.01, SEE = 0.23 g/cm2). Hence, 1RM for multi-joint exercises is relevant to BMC and BMD in young men, strengthening the relationship between force and LM, and suggesting both to parametrizes bone mineral health.

Resposta fisiológica e perceptual na velocidade crítica e ponto de compensação respiratória / Physiological and perceptual response at critical speed and respiratory compensation point / Respuesta fisiológica y perceptual en la velocidad crítica y punto de compensación respiratoria

RESUMO Introdução: O ponto de compensação respiratória (PCR) representa a taxa metabólica durante um teste incremental máximo, a partir da qual se perde o controle do equilíbrio ácido-base. Entretanto, a velocidade crítica (VC) define o limite superior do domínio pesado do exercício, no qual a exaustão não está relacionada à perturbação metabólica. Objetivo: Comparar a resposta fisiológica (frequência cardíaca - FC, lactato sanguíneo - [La] e consumo de oxigênio - V̇O2) e perceptual (percepção subjetiva de esforço - PSE) durante o exercício na VC e no PCR, visando analisar as similaridades contextuais. Métodos: Dez corredores adolescentes (15,8 ± 1,7 anos) submeteram-se a um teste progressivo (incrementos de 1,0 km×h-1 por minuto, até a exaustão) para determinar V̇O2max, PCR e velocidades correspondentes. A VC foi estimada por três esforços, com tempo limite previsto entre 2 e 12 minutos. Os participantes realizaram dois esforços de sete minutos cada, em dias diferentes, na VC e vPCR. Foram registradas FC, PSE (escala 6-20) a cada minuto e [La] de repouso e após cada esforço. O V̇O2 foi analisado respiração a respiração durante os esforços. O teste de Mann-Whitney comparou as respostas de FC, [La], V̇O2 e PSE em VC e vPCR. A variância entre essas respostas foi analisada pelo coeficiente de dispersão (R2). O índice de significância foi P≤0,05. Resultados: Os valores máximos no teste progressivo foram 56,1 ± 5,5 ml×kg-1×min-1 (V̇O2max), 16,5 ± 1,7 km×h-1 (vV̇O2max), 202 ± 12 bpm (FCmax), 19,4 ± 1,3 (PSE) e 12,7 ± 3,1 mmol×L-1 ([La]). Não foram observadas diferenças entre VC (a 83,8 ± 3,6% vV̇O2max) e vPCR (a 86,5 ± 3,6% vV̇O2max) nas respostas de PSE (P = 0,761), FC (P = 0,096), [La] (P = 0,104) e V̇O2 (P = 0,364). Demonstrou-se haver correlações entre VC e vPCR nas respostas de [La] (R2 = 0,76; P = 0,011), PSE (R2 = 0,84; P < 0,01) e V̇O2max (R2 = 0,82; P < 0,01). Conclusão: Pode-se inferir que o exercício em PCR reproduziu uma resposta fisiológica e perceptual similar àquela em VC.

ABSTRACT Introduction: The respiratory compensation point (RCP) is the metabolic rate for a maximal incremental test, from which the control of the acid-base balance is lost. However, the critical velocity (CV) defines the upper limit of the heavy exercise domain, in which the exhaustion is not related to metabolic disturbance. Objective: To compare the physiological (heart rate - HR, blood lactate - [La], and oxygen uptake - V̇O2) and perceptual (rating of perceived exertion - RPE) responses, while exercising at CV and at RCP, in order to analyze contextual similarities. Methods: Ten adolescent runners (15.8±1.7 years old) underwent progressive test (increments of 1.0 km×h-1 per minute until exhaustion) to determine V̇O2max, RCP and the correspondent velocities. The CV was estimated for three efforts with time limit of 2 to 12 minutes. The participants performed two efforts of seven minutes each on separate days, in CV and vRCP HR, RPE (scale 6-20) were recorded every minute, and [La] was measured at rest and after each effort. The V̇O2 was analyzed breath by breath during efforts. The Mann-Whitney test compared HR, [La], V̇O2, and RPE responses in CV and vRCP. The variance between these responses was examined by the scatter coefficient (R2). The significance level was P≤0.05. Results: The maximum values in the progressive test were 56.1±5.5 ml×kg-1×min-1 (V̇O2max), 16.5±1.7 km×h-1 (vV̇O2max), 202±12 bpm (HRmax), 19.4±1.3 (RPE) and 12.7±3.1 mmol×L-1 ([La]). No differences were observed between CV (at 83.8±3.6% vV̇O2max) and vRCP (at 86.5±3.6% vV̇O2max) in RPE responses (P=0.761), HR (P=0.096), [La] (P=0.104) and V̇O2 (P=0.364) responses. Correlations were observed between the CV and vRCP in [La] (R2=0.76; P=0.011), RPE (R2=0.84; P<0.01) and V̇O2max (R2=0.82; P<0.01) responses. Conclusion: It was inferred that exercise in RCP reproduced a physiological and perceptual response similar to that in CV.

RESUMEN Introducción: El punto de compensación respiratoria (PCR) es la tasa metabólica para un test incremental máximo, a partir de la cual se pierde el equilibrio ácido-base. Sin embargo, la velocidad crítica (VC) define el límite superior del dominio de ejercicio pesado, en el que el agotamiento no está relacionado con el trastorno metabólico. Objetivo: Comparar la respuesta fisiológica (frecuencia cardiaca - FC, lactato en sangre - [La] y consumo de oxígeno - V̇O2) y la perceptual (percepción subjetiva del esfuerzo - PSE) en VC y PCR con el fin de analizar las similitudes contextuales. Métodos: Diez corredores adolescentes (15,8 ± 1,7 años) fueron sometidos a una prueba progresiva (incrementos de 1,0 km×h-1 por minuto hasta el agotamiento) para determinar V̇O2max, PCR y las velocidades correspondientes. La VC se estimó por tres esfuerzos con tiempo límite previsto entre 2 y 12 minutos. Los participantes realizaron dos esfuerzos de siete minutos cada en diferentes días en VC y vPCR. Se registraron, FC, PSE (escala 6-20) cada minuto y [La] de reposo y después de cada esfuerzo. El V̇O2 se analizó respiración a respiración durante el esfuerzo. La prueba de Mann-Whitney comparó las respuestas de FC, [La], V̇O2 y PSE en VC y vPCR. La varianza entre estas respuestas fue examinada por el coeficiente de dispersión (R2). El nivel de significación fue de P ≤ 0,05. Resultados: Los valores máximos en la prueba progresiva fueron 56,1 ± 5,5 ml×kg-1×min-1 (V̇O2max), 16,5 ± 1,7 km×h-1 (vV̇O2max), 202 ± 12 lpm (FCmax), 19,4 ± 1,3 (PSE) y 12,7 ± 3,1 mmol×l-1 ([La]). No se observaron diferencias entre VC (en 83,8 ± 3,6% vV̇O2max) y vPCR (en 86,5 ± 3,6% vV̇O2max), en las respuestas de PSE (P = 0,761), FC (P = 0,096), [La] (P = 0,104) y V̇O2 (P = 0,364). Se ha demostrado que hay correlaciones entre CV y vPCR en las respuestas del [La] (R2 = 0,76, P = 0,011), PSE (R2 = 0,84, P<0,01) y del V̇O2max (R2 = 0,82; P < 0,01). Conclusión: Se puede deducir que el ejercicio en PCR reproduce una respuesta fisiológica y perceptual similar a la respuesta en VC.