Physiological mechanisms of muscle strength and power are dependent on the years post obtaining peak height velocity in elite juniors rowers: A cross-sectional study.

BACKGROUND: It is not yet known whether the years after peak height velocity (PHV) are associated with the physiological mechanisms of muscle strength and power in Juniors rowers. OBJECTIVE: To identify the association between years post PHV (YPPHV) with muscle power and strength in Juniors rowers. METHODS: We tested 235 Brazilian rowing athletes (male: 171, female: 64, Juniors category). We measured: power (indoor rowing over 100-m, 500-m, 2,000-m and 6,000-m) and muscle strength (one repetition maximum (1RM) test in squat, deadlift, bench press and bent row on the bench). Biological maturation was index by age of PHV. The sample was divided into groups considering YPPHV recent (2.5 to 3.9), median (2.51 to 4.9) and veteran (>4.9). We use a Baysian approach to data handling. RESULTS: When compared to their peers in the recent and median post PHV groups, the male veteran group were superior in muscle power (Absolute: 100-m (BF10: 2893.85), 500-m (BF10: 553.77) and 6,000-m (BF10: 22.31). Relative: (100-m (BF10: 49.9)) and strength (BF10≥10.0 in squat, bench press and deadlift), and in the female the veteran group were superior in test time (500-m, BF10: 88.4). CONCLUSION: In elite Juniors rowers the increasing YPPHV are associated with muscle power performance in both sexes and muscle strength performance in males.

Acute Effect of Resistance Training With Blood Flow Restriction on Perceptual Responses: A Systematic Review and Meta-Analysis.

CONTEXT: Several studies have compared perceptual responses between resistance exercise with blood flow restriction and traditional resistance exercise (non-BFR). However, the results were contradictory. OBJECTIVES: To analyze the effect of RE+BFR versus non-BFR resistance exercise [low-load resistance exercise (LL-RE) or high-load resistance exercise (HL-RE)] on perceptual responses. DATA SOURCES: CINAHL, Cochrane Library, PubMed®, Scopus, SPORTDiscus, and Web of Science were searched through August 28, 2021, and again on August 25, 2022. STUDY SELECTION: Studies comparing the effect of RE+BFR versus non-BFR resistance exercise on rate of perceived exertion (RPE) and muscle pain/discomfort were considered. Meta-analyses were conducted using the random effects model. STUDY DESIGN: Systematic review and meta-analysis. LEVEL OF EVIDENCE: Level 2. DATA EXTRACTION: All data were reviewed and extracted independently by 2 reviewers. Disagreements were resolved by a third reviewer. RESULTS: Thirty studies were included in this review. In a fixed repetition scheme, the RPE [standardized mean difference (SMD) = 1.04; P < 0.01] and discomfort (SMD = 1.10; P < 0.01) were higher in RE+BFR than in non-BFR LL-RE, but similar in sets to voluntary failure. There were no significant differences in RPE in the comparisons between RE+BFR and non-BFR HL-RE; after sensitivity analyses, it was found that the RPE was higher in non-BFR HL-RE in a fixed repetition scheme. In sets to voluntary failure, discomfort was higher in RE+BFR versus non-BFR HL-RE (SMD = 0.95; P < 0. 01); however, in a fixed scheme, the results were similar. CONCLUSION: In sets to voluntary failure, RPE is similar between RE+BFR and non-BFR exercise. In fixed repetition schemes, RE+BFR seems to promote higher RPE than non-BFR LL-RE and less than HL-RE. In sets to failure, discomfort appears to be similar between LL-RE with and without BFR; however, RE+BFR appears to promote greater discomfort than HL-RE. In fixed repetition schemes, the discomfort appears to be no different between RE+BFR and HL-RE, but is lower in non-BFR LL-RE.

Physiological adaptations and myocellular stress in short-term, high-frequency blood flow restriction training: A scoping review.

BACKGROUND: High frequency (1-2 times per day) low-intensity blood flow restriction (BFR) training has been recommended as a prescription approach for short durations of time to maximize relevant physiological adaptations. However, some studies demonstrate negative physiological changes after short periods of high-frequency BFR training, including prolonged strength decline and muscle fiber atrophy. OBJECTIVES: To provide a comprehensive overview of short-term, high-frequency blood flow restriction training, including main adaptations, myocellular stress, limitations in the literature, and future perspectives. METHODS: A systematic search of electronic databases (Scopus, PubMed®, and Web of Science) was performed from the earliest record to April 23, 2022. Two independent reviewers selected experimental studies that analyzed physical training protocols (aerobic or resistance) of high weekly frequency (>4 days/week) and short durations (≤3 weeks). RESULTS: In total, 22 studies were included in this review. The samples were composed exclusively of young predominantly male individuals. Muscle strength and hypertrophy were the main outcomes analyzed in the studies. In general, studies have demonstrated increases in strength and muscle size after short term (1-3 weeks), high-frequency low-intensity BFR training, non-failure, but not after control conditions (non-BFR; equalized training volume). Under failure conditions, some studies have demonstrated strength decline and muscle fiber atrophy after BFR conditions, accompanying increases in muscle damage markers. Significant limitations exist in the current HF-BFR literature due to large heterogeneities in methodologies. CONCLUSION: The synthesis presented indicates that short-term, high-frequency BFR training programs can generate significant neuromuscular adaptations. However, in resistance training to failure, strength declines and muscle fiber atrophy were reported. Currently, there are no studies analyzing low-frequency vs. high-frequency in short-term BFR training. Comparisons between resistance exercises of similar intensities (e.g., combined effort) are lacking, limiting conclusions on whether the effect is a product of proximity to failure or a specific effect of BFR.

Factors related to lower limb performance in children and adolescents aged 7 to 17 years: A systematic review with meta-analysis.

BACKGROUND: The literature identifies several factors that are associated with lower limb performance (LLP). However, there is little consensus on which factors have the major associations with LLP. OBJECTIVE: Examine, analyze and summarize the scientific evidence on the factors associated with the performance of LLP in children and adolescents of both sexes aged between 7 and 17 years. DESIGN: This systematic review was conducted following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement and was registered in PROSPERO. DATA SOURCES: A systematic literature search of five electronic databases (i.e., SPORTDiscus, PubMed, CINAHL, Google Scholar, and SCOPUS) with date restrictions was conducted (2010 to 2021). ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Eligibility criteria included (i) a study published between 2010 and 2021; (ii) a research study with observational design; (iii) a study analyzing LLP; and (iv) a sample composed of young people between 7 and 17 years old (regardless of sex). ANALYSES: Literature analysis was carried out in English and Portuguese between 2018 and 2021, "blindly" by two researchers. For data sorting, Rayyan® was used. Data extraction and evidence analysis were performed "blindly", using the Loney scale. The minimum items for observational studies were analyzed by the STROBE checklist. Meta-analyses were conducted based on age group (Childhood [7 to 11 Yrs] and Adolescence [12 to 17 Yrs]) and puberty stages (i.e., Prepupertal and Pubertal). The heterogeneity between the samples of the studies was assessed using the "Cochran's Q" and "I^2" statistics. Meta-regression analyses were performed to check the factors related to heterogeneity of the studies and to check the associations between chronological age and LLP. RESULTS: The literature search resulted in 1,109,650 observational studies of which 39 were included in this review. Through Meta-analysis and Meta-regressions, it was possible to indicate that advancing chronological age related to increased LLP (p<0.01), and that in relation to puberty stages pubertal subjects had higher LLP than their pre-pubertal peers (p<0.01). DISCUSSION: The main findings of the present systematic review suggest that as chronological age advances (childhood to adolescence), neuromuscular systems mature and this may be due to advancing puberty, which is also associated with an increase in LLP. CONCLUSION: The factors associated with lower limbs performance are still inconsistent in the literature. However, advancing chronological age and stage of puberty are both associated with increased lower limbs performance. TRIAL REGISTRATION: ID-PROSPERO-CRD42020137925.

Lean mass and biological maturation as predictors of muscle power and strength performance in young athletes.

BACKGROUND: The biological maturation (BM) analyzed by peak height velocity (PHV) and bone age (BA), and lean body mass has been associated with the strength and muscle power of young athletes. However, the ability of BM (PHV and BA) and LM markers to predict muscle strength and power in young athletes remains uncertain. OBJECTIVE: The Aim was determine the predicting power of BM markers (PHV and BA) and LM in relation to muscle power of upper and lower limbs and muscle strength of upper limbs in adolescent athletes at puberty. METHODS: Ninety-two adolescent athletes (both sexes; age 12.4 ± 1.02 years) were assessed for body composition by dual-energy X-ray absorptiometry (DXA). Power of upper limbs (ULP), force handgrip (HG), vertical jump (VJ) and countermovement jump (CMJ) were recorded. BM was predicted by mathematical models to estimate PHV and BA. Multilayer artificial neural network analyses (MLP's) were used to determine the power of prediction of LM, PHV and BA on muscle power and strength of upper- and lower-limbs of the athletes. RESULTS: LM, BA and PHV were associated with HG (r>0.74, p<0.05) and ULS (r>0.60, p<0.05) in both sexes. In both sexes BA was associated with VJ (r>0.55, p<0.05) and CMJ (r>0.53, p<0.05). LM indicated associations (r>0.60, p<0.05) with BA and with PHV (r<0.83, p<0.05) in both sexes. MLP's analysis revealed that the LM provides > 72% of probability to predict the muscle power of upper- and lower-limbs, and the strength of the upper limbs; whereas PHV provides > 43% and bone age >64% in both female and male adolescent athletes. CONCLUSION: We identified that, like PHV and BA, LM is a strong predictor of low cost of both upper limbs muscle strength and upper and lower limbs power in adolescent athletes.

Biological Maturation and Hormonal Markers, Relationship to Neuromotor Performance in Female Children.

Background: Mechanisms that influence muscle strength can interfere with neuromotor performance and overall health, thus hormone markers and maturation can interact in this process. Objective: The present study aimed to verify the relationship of hormonal markers and biological maturation on neuromotor abilities in young people. Methods: This is a cross-sectional study with 44 female participants (11.5 ± 1.5 years). Hormones were analyzed biochemically. Skeletal and somatic maturation were analyzed using anthropometry. The muscular power of the upper and lower limbs, body speed with change of direction, and speed of the upper limbs were verified. Results: Bone age was correlated with hormonal markers (estradiol: r = 0.58; p = 0.0007), (testosterone: r = 0.51; p = 0.005). Peak growth velocity correlated with estradiol (r = 0.51; p = 0.004). The power of the lower limbs (estradiol: r = 0.52; p = 0.006; testosterone: r = 0.42; p = 0.03) and of the upper limbs (estradiol: r = 0.51; p = 0.007; testosterone: r = 0.42; p = 0.02) had a positive correlation with hormone levels and had similar results with maturation. The analysis by artificial neural networks indicated that the maturation can predict the neuromotor performance between 57.4% and 76%, while the hormonal markers showed a potential of more than 95% for the foreshadowing of the neuromotor performance of the upper limbs. Conclusion: It was possible to conclude that the hormones had a relationship with maturational development and bone age in female subjects.

Impact of curcumin on energy metabolism in HIV infection: A case study.

Prolonged use of antiretroviral therapy (ART) has been associated with dyslipidemia and impaired energy substrate oxidation (SOxi). Curcumin is a natural bioactive compound, which interacts with molecular targets and holds important metabolic properties. The aim of this study was to evaluate the effect of curcumin supplementation on energetic metabolism of an adult female with HIV/AIDS and under ART. The intervention was performed with 500 mg/day of curcumin for 27 days. Glycemic and lipid profile and SOxi at rest were evaluated before and after intervention. After intervention, improvement of lipid profile and insulin sensibility was observed. Moreover, there was a positive modulation of SOxi at rest. Oral curcumin supplementation can positively modulate the energy metabolism of people living with HIV/AIDS using the ART. However, clinical studies are required in order to confirm our findings in a representative sample.

[Effects of differerent types of training and life styles on anthropometric and cardiocirculatory markers in aging]. / Efeitos de Diferentes Treinamentos e Estilos de Vida nos Indicadores Antropométricos e Cardiocirculatórios no Envelhecimento.

OBJECTIVE: The aim of this experimental study was to compare the effects of different forms of training and life styles on hemodynamic markers, cardiac capacity, Waist-to-Hip Ratio-WHR and Body Mass Index-BMI in elders, between 60-69 years, of both sexes. MATERIALS AND METHODS: The sample was composed of elders, between 60-69 years, of both sexes: masculine N=159 and feminine N=157. They were divided into three groups: experimental 1: n=53 (masculine) and n=51 (feminine) activity: cardio respiratory endurance; experimental 2: n=53 (masculine) and n=53 (feminine) activity: resistance training with Local Muscle Resistance-RML; control group: n=53 (masculine) and n=53 (feminine) who didn t practice any regular physical activity, considered sedentary. The variables investigated were BMI, WHR, Cardiac Frequency at rest, Systolic Blood Pressure, Diastolic Blood Pressure, Mean Blood Pressure and Double Product. The data analysis was descriptive and inferential and comparisons were performed between groups and inter groups. The data collected in this study and the hypothesis test showed the benefits of physical activity on the selected parameters for observation. RESULTS: It was demonstrated the existence of significative difference (p<0.05) in the studied variables. CONCLUSIONS: There is a need for adherence in broad-spectrum physical activity in elders.

Efeitos de Diferentes Treinamentos e Estilos de Vida nos Indicadores Antropométricos e Cardiocirculatórios no Envelhecimento / Effects of differerent types of training and life styles on anthropometric and cardiocirculatory markers in aging / Efectos de diferentes tipos de entrenamiento y estilos de vida sobre indicadores antropométricos y cardiocirculatorios en el envejecimiento

Objetivo O presente estudo, de caráter experimental, pretende comparar os efeitos de diferentes formas de treinamento e estilo de vida sobre os indicadores hemodinâmicos, capacidade cardíaca, relação cintura quadril e índice de massa corporal, em adultos velhos de ambos os sexos entre 60 e 69 anos de idade. Materiais e Métodos As amostras utilizaram adultos velhos de 60 a 69 anos de ambos os sexos: masculino N=159 e feminino N=157, divididos em três grupos: experimental 1, n=53 (masculino) e n=51 (feminino) atividade endurance cardio-respitatório; experimental 2, n=53 (masculino) e n=53 (feminino) atividade musculação com séries de Resistência Muscular Localizada (RML); controle n=53 (masculino) e n=53 (feminino) não praticantes de atividade física considerados sedentários. As variáveis investigadas foram Índice de Massa Corporal (IMC) e Relação Cintura Quadril (RCQ), Freqüência Cardíaca de Repouso (FCrep), Pressão Arterial Sistólica (PAS), Pressão Arterial Diastólica (PAD), Pressão Arterial Média (PAM) e Duplo Produto (DP). As estatísticas utilizadas foram a descritiva e a inferencial a comparação intra e entre grupos. Os dados coletados neste estudo e o teste de hipótese demonstram os benefícios da atividade física, nos parâmetros escolhidos para observação. Resultados Foi demonstrada a existência de uma diferença significativa (p<0.05) nas variáveis estudadas. Conclusões Há necessidade da aderência à atividade física de amplo espectro nas idades mais avançadas.

Objective The aim of this experimental study was to compare the effects of different forms of training and life styles on hemodynamic markers, cardiac capacity, Waist-to-Hip Ratio-WHR and Body Mass Index-BMI in elders, between 60-69 years, of both sexes. Materials and Methods The sample was composed of elders, between 60-69 years, of both sexes: masculine N=159 and feminine N=157. They were divided into three groups: experimental 1: n=53 (masculine) and n=51 (feminine) activity: cardio respiratory endurance; experimental 2: n=53 (masculine) and n=53 (feminine) activity: resistance training with Local Muscle ResistanceRML; control group: n=53 (masculine) and n=53 (feminine) who didn´t practice any regular physical activity, considered sedentary. The variables investigated were BMI, WHR, Cardiac Frequency at rest, Systolic Blood Pressure, Diastolic Blood Pressure, Mean Blood Pressure and Double Product. The data analysis was descriptive and inferential and comparisons were performed between groups and inter groups. The data collected in this study and the hypothesis test showed the benefits of physical activity on the selected parameters for observation. Results It was demonstrated the existence of significative difference (p<0.05) in the studied variables. Conclusions There is a need for adherence in broad-spectrum physical activity in elders.

Objetivo El presente estudio, de carácter exploratorio, se propuso comparar los efectos de diferentes tipos de entrenamiento y estilos de vida sobre indicadores hemodinámicos, capacidad cardíaca, relación cintura/caderaRCC e Índice de Masa CorporalIMC, en personas de 60 a 69 años de edad, de los dos sexos. Materiales y Métodos La muestra se conformó con personas de 60 a 69 años de edad, de los dos sexos: masculino N=159 y feminino N=157, divididos en tres grupos: experimental 1 n=53 (masculino) y n=51 (feminino). Actividad: terapia cardiorrespiratoria; experimental 2 n=53 (masculino) y n=53 (feminino). Actividad: Ejercicios Localizados de Resistencia-RML; Control n=53 (masculino) y n=53 (femenino) que no realizó actividad física, y considerados sedentarios. Las variables investigadas fueron: Indice de masa corporal-IMC, Relación cintura cadera-RCC, Frecuencia cardíaca en reposo-FCrep, Presión arterial sistólica-PAS, Presión arterial diatólica-PAD, Presión arterial media-PAM y Producto Doble-DP. Se utilizaron estadísticas descriptivas e inferenciales, y comparación intra y entre grupos. Los datos obtenidos y la prueba de la hipótesis muestran los beneficios de la actividad física, en los parámetros elegidos para observación. Resultados Se demostró la existencia de un significativa diferencia (p<0.05) en las variables estudiadas. Conclusiones En las edades avanzadas se requiere la adhesión a la actividad física de amplio espectro.