Emerson Silami Garcia

Evaluation of waist circumference to predict general obesity and arterial hypertension in women in Greater Metropolitan Belo Horizonte, Brazil

This study examined the capacity of waist circumference (WC) to identify subjects with overweight (BMI >/=25) and obesity (BMI >/=30), in agreement with internationally recommended levels of action. Data were obtained from 791 women, 15-59 years old. After identifying overweight and obesity according to WC values, sensitivity and specificity were calculated to verify whether WC could be a good risk predictor for hypertension. Associations were tested by linear regression and logistic regression, controlling for confounding. WC cut-off points of 80cm and 88cm correctly identified 89.8% and 88.5% of women with overweight and obesity, respectively. Abdominal obesity (WC >/=88cm) was statistically associated with hypertension in the multivariate analysis (OR = 2.88; 95% CI: 1.77-4.67). Hypertension was identified with a sensitivity of 63.8% and 42.8%, and with a specificity of 68.0% and 83.3%, for WC >/=80 and >/=88, respectively. The proposed cut-off points for abdominal obesity can potentially distinguish individuals at risk for future obesity, but has only moderate power to predict individuals with high blood pressure.

Avaliação da capacidade preditiva da circunferência da cintura para obesidade global e hipertensão arterial em mulheres residentes na Região Metropolitana de Belo Horizonte, Brasil

Data from the Brazilian Ministry of Health and the literature indicate that adolescents may be overrepresented in the prevalence of maternal morbidity and mortality and neonatal complications. This study focused on childbirth and live newborns among adolescent and young adult mothers in the municipality of Feira de Santana, Bahia, identifying risk factors for morbidity and mortality. A cross-sectional cohort study was conducted based on data from the Information System on Live Births (SINASC) in the municipality in 1998, totaling 5,279 live births among adolescent (10 to 19 years) and young adult mothers (20 to 24 years). Variables were age, schooling, prenatal care, gestational care, form of delivery, and birthweight. The authors measured the association between maternal age and the childs birthweight, while controlling potential confounders. Some 21.6% of live births were to adolescent mothers, 51.2% of whom had not finished primary school; there was an association between the 10 to 16-year age bracket and incomplete primary schooling, lack of prenatal care, and low and insufficient birthweight as compared to the other age brackets; there was also a high rate of underrecording in the SINASC. The results suggest the need for specific measures focusing on the reproductive health of adolescents in the municipality.

Six weeks of aerobic training improves VO2max and MLSS but does not improve the time to fatigue at the MLSS

The purpose of this study was to investigate the effects of a 6-week aerobic training period on the time to fatigue (tlim) during exercise performed at the maximal lactate steady state (MLSS). Thirteen untrained male subjects (TG; age 22.5xa0±xa02.4xa0years, body mass 72.9xa0±xa06.7xa0kg and VO2max 44.9xa0±xa04.8xa0mL kg−1 min−1) performed a cycle ergometer test until fatigue at the MLSS power output before and after 6xa0weeks of aerobic training. A group of eight control subjects (CG; age 25.1xa0±xa02.4xa0years, body mass 70.1xa0±xa09.8xa0kg and VO2max 45.2xa0±xa04.1xa0mL kg−1 min−1) also performed the two tests but did not train during the 6-week period. There were no differences between the groups with respect to the VO2max or MLSS power output (MLSSw) before the treatment period. The VO2max and the MLSSw of the TG increased by 11.2xa0±xa07.2xa0% (pre-treatmentxa0=xa044.9xa0±xa04.8 vs. post-treatmentxa0=xa049.8xa0±xa04.5xa0mL kg−1 min−1) and 14.7xa0±xa08.9xa0% (pre-treatmentxa0=xa0150xa0±xa027 vs. post-treatmentxa0=xa0171xa0±xa026xa0W), respectively, after 6xa0weeks of training. The results of the CG were unchanged. There were no differences in tlim between the groups or within groups before and after training. Six weeks of aerobic training increases MLSSw and VO2max, but it does not alter the tlim at the MLSS.

Yo-Yo IR2 test e teste de margaria: validade, confiabilidade e obtenção da frequência cardíaca máxima em jogadores jovens de futebol

The aims of the present study were: i) to evaluate the construct validity of Yo-Yo Intermittent Recovery Test Level 2 (Yo-Yo IR2) and of the Margaria Test (MT) with performance in high intensity exercise during official games in soccer players; ii) to verify the reliability (test-retest) of the two tests; iii) to compare the values of the maximal individual heart rate (MHR) obtained in those protocols and in game. Eighteen players (mean ± SD; age 14 ± 0.8 years, height 172 ± 9 cm, weight 64.3 ± 8.5 kg) belonging to the same team were assessed in test-retest referred protocols and in the percentage of time spent above 85% of MHR (PTS>85%MHR) in two official games of the U-15 Championship. High correlation was found between performance in the Yo-Yo IR2 and PTS>85%MHR (rs=0.71; p 85%MHR (rs=0.44; p=0.06). The Yo-Yo IR2 was more variable and less reproducible (CV= 11%; CCI [95% IC]=0.38) than MT (CV= 1%; CCI [95% IC]=0.93). The highest value of MHR (p<0.001) occurred in the game (202 ± 8 beats.min-1). MHR in Yo-Yo IR2 (194 ± 4 beats.min-1) was lower (p<0,006) than MT (197 ± 6 beats.min-1). In conclusion, the Yo-Yo IR2 can be considered more valid to predict maintenance of high exercise intensity during a match, which is an important performance measure in soccer. However, there is need of strict standardization among the evaluation procedures for stability of the measure. MHR should be observed in several situations, mainly competitive, so that the highest individual value can be reached.

Effects of Precooling on 30-km Cycling Performance and Pacing in Hot and Temperate Environments

This study examined the effects of precooling on performance and pacing during 30-km cycling exercise in hot and temperate environments. 8 trained male cyclists performed 4 trials involving either cooling (PRECTEMP and PRECHOT) or no-cooling interventions (TEMP and HOT) prior to a 30-km self-paced cycling exercise in either a hot (35°C, 68% relative humidity) or temperate environment (24°C, 68% relative humidity). Exercise time was longer in HOT (60.62±3.47u2009min) than in TEMP (58.28±3.30u2009min; P<0.001), and precooling attenuated this thermal strain performance impairment (PRECHOT 58.28±3.30u2009min; P=0.048), but it was still impaired compared with TEMP (P=0.02). Exercise performance in PRECTEMP (54.58±4.35u2009min) was no different from TEMP. Initial power output was sustained until the end of the exercise in both TEMP and PRECTEMP, but was reduced from the 12th km until the end of the trial in HOT (P<0.05). This reduction was delayed by precooling because power output was reduced only after the 20th km during PRECHOT (P<0.05). Heart rate was similar in all conditions throughout almost the entire exercise, suggesting the maintenance of similar relative intensities. In conclusion, precooling was effective in attenuating, but not completely reversing thermal strain performance impairment and offered no ergogenic effect in the temperate environment.

Maximal power output estimates the MLSS before and after aerobic training

The purpose of this study is to present an equation to predict the maximal lactate steady state (MLSS) through a VO2peak incremental protocol. Twenty-six physically active men were divided in two groups (G1 and G2). They performed one maximal incremental test to determine their VO2peak and maximal power output (Wpeak), and also several constant intensity tests to determine MLSS intensity (MLSSw) on a cycle ergometer. Group G2 underwent six weeks of aerobic training at MLSSw. A regression equation was created using G1 subjects Wpeak and MLSSw to estimate the MLSS intensity (MLSSweq) before and after training for G2 (MLSSweq = 0.866 x Wpeak-41.734). The mean values were not different (150±27W vs 148±27W, before training / 171±26W vs 177±24W, after training) and significant correlations were found between the measured and the estimated MLSSw before (r²=0.49) and after training (r²=0.62) in G2. The proposed equation was effective to estimate the MLSS intensity before and after aerobic training.

Efeitos do calor no OBLA: comparação entre ambiente quente e temperado

Abstract: The OBLA (onset of blood lactate accumulation), is a method used to estimate the lactate threshold (LT). However, It is unclear the effect of ambient temperature on OBLA. The aim of this study was to compare OBLA determined in warm (40°C) and temperate (22oC) environments. Nine men (age: 23.9±2.4 years, body mass: 75.9±7.3kg and VO 2 max: 47.8±4.9 mL•kg -1 •min -1 ) performed an incremental test in cycle ergometer to determine the maximal power output (Wmax) and OBLA in the heat (OBLA-40) and temperate (OBLA-22) environments. The Wmax (195±25W vs 225±28W) and the power output associated with the OBLA (153±30 W vs 165±32W) were lower in warm than in temperate experiments. The heart rate at OBLA-40 was higher than in OBLA-22 (171±8 vs 153±10 bpm, respectively). No difference was found in oxygen uptake at OBLA-22 and OBLA-40 (31.65±5.21 vs 31.12±6.82 mL•kg -1 •min -1 ). The results indicate that environmental conditions influence the OBLA determination.

Creatine kinase kinetics in professional soccer players during a competitive season. DOI: 10.5007/1980-0037.2011v13n3p189

Serum creatine kinase (CK) concentration has been widely used as an indicator of skeletal muscle damage in sports. However, there are no longitunal studies on post-game CK kinetics in Soccer during a competitive season.xa0The aimxa0of this study was to evaluate serum CK kinetics in professional Soccer players at different post-game times during a competitive season without training interruption. Seventeen professional soccer players (age: 22.2±3.1 years, height: 179±6.0 cm, body fat percentage: 9.5±1.1, and 67.0±3.5 mL O2/kg/min) were evaluated over a period of 3 months of the national championship. Serum CK concentration was measured before the beginning of the season (baseline) and at four different times after a soccer game (post-1: 12-20 h, post-2: 36-48 h, post-3: 60-65 h, and post-4: 90-110 h).xa0Plasma CK concentrations were higher at all times when compared to baseline (p<0.05). Post-2 CK concentration was lower than post-1 and higher than post-3 and -4 (p<0.05), with no significant differences between post-3 and post-4.xa0In conclusion, serum CK kinetics was influenced by the training routine of the soccer players, with a peak between 12 and 20 h after the game, returning to normal within 60-65 h. This procedure can be used to monitor the recovery state of athletes and game and training intensities.