Thales Boaventura Rachid Nascimento

Influence of body composition and age on bone density in relation to levels of physical activity

OBJECTIVES Verify the physical activity level (PAL), to what extent each body composition component and age influence bone density (BD). METHODS Samples of 22 men and 42 women (21-51 years) classified with recommended and not recommended PAL for health. The femurs BD measured using DXA. RESULTS Using a analyzing the stepwise linear regression (p < or = .05), the age explained negatively BD for all groups, except men with recommended PAL. Among women group with not recommended PAL, the relative fat (%F) and body fat (BF) explained the BD increasing to 0.007 g/cm(2) per BF kilogram in all regions of interest in the femur. CONCLUSION The BD in Wards area has been mostly influenced by age in women. The FM and %F have positive influence on BD among women with low PAL.

A Variação do método de incremento de cargas não altera a determinação do limiar de lactato em exercício resistido

The aim of this investigation was to analyze and compare different incremental protocols (IP) to identify the lactate threshold (LT) in resistance exercise. 12 male volunteers (23.3 ± 1.6 years) adapted to resistance exercise were submitted to two incremental tests performed in leg-press 45o (LP). The IP were: 1) concerned with the maximum workload test (IP%1RM), with incremental load corresponding to 19, 28, 32, 37, 41, 45, 55 and 60% of 1RM; 2) concerned with the body weight (IP%BW), with incremental load of 17, 33, 50, 67, 83, 100, 117 and 133% of the BW. Both IP had stage duration of 1-min, each with 30 repetitions. During intervals between stages (2-min to IP%1RM and 1-min to IP%BW), 25 µL of blood were collected from ear lobe and then placed in Eppendorff microtubes for blood lactate concentration [Lac] dosing. It was possible to identify LT from the responses of the [Lac] in both protocols. No significant differences were observed between the LT intensities determined by absolute (IP%1RM - 72.3 ± 12.5 vs. IP%BW - 65.9 ± 11.5 kg; p > 0.05) and relative loads (IP%1RM - 32.3 ± 4.2 vs. IP%BW - 31.6 ± 4.3 %1-RM; p > 0.05). High correlation was observed between the IP%1RM and IP%BW both for absolute (r = 0.90; p < 0.01) as well as for relative loads (r = 0.83; p < 0.01). In conclusion, despite protocols modifications during the incremental test on resistance exercise, it was possible to identify the LT in LP in the studies sample in which relative and absolute intensities did not differ from each other and presented high correlation between them. The results suggest that LT in resistance exercise should be identified through a protocol with increments based on the BW %. Such procedure has the advantage of not submitting the participant to a previous 1 RM incremental test.

Excesso de adiposidade corporal em adolescentes: associação com fatores sociodemográficos e aptidão física

The objective was to verify the prevalence and factors associated with high body fat in adolescents from Januaria-MG, Brazil. The sample included 266 boys and 361 girls (15,47±1,06 years old). Adiposity was estimated by the sum of triceps and subscapular skinfold thickness. The independent variables were: area of residence (urban and rural); age (14-15 and 16-17 years old); house income (high, medium and low); aerobic fitness, flexibility and muscular resistance (adequate and inadequate). Among boys, 13,91% exhibited adiposity excess, with higher (p<0.05) skinfold thicknesses sum been observed among boys with low house income and urban residence. Among girls, 33,24% exhibited adiposity excess, with higher (p<0.05) skinfold thicknesses sum been observed among girls with 16-17 years old and low house income. Adiposity excess was associates, only in boys, with urban residence and inadequate muscular resistance. Thus, boys seem to be more susceptible to environmental factors than girls.