Influence of Trunk Position during Three Lunge Exercises on Muscular Activation in Trained Women.

The present study aimed to compare the activation of the lower lumbar erector spinae, gluteus maximus, biceps femoris, and rectus femoris in two trunk positions (straight, and inclined) during three lunge exercises (static, step-forwarding, and walking) in trained young women in a randomized crossover design. Twelve women (24 ± 3 years) were selected and performed the lunge exercise with an overload of 30% of body weight in six conditions to analyze muscle activation via surface electromyography signals. Higher activation in the erector spinae (%MVIC) were observed (p < 0.05) when trunk position was inclined (straight = 20 ± 15, inclined = 40 ± 29) and during the walking lunge condition (static = 24 ± 16, forward = 26 ± 22, walking = 40 ± 33). Higher activation in the gluteus maximus was observed during step-forward and walking lunges conditions (static = 31 ± 12, forward = 54 ± 20, walking = 58 ± 30). All conditions displayed similar activations in the biceps femoris and rectus femoris (p > 0.05). Results indicate that positioning the trunk in a forward-inclined position induces greater lower lumbar erector spinae activation and dynamic lunge variations elicit greater muscular activation in the gluteus maximus than static lunges. Additionally, it seems that trunk and exercise variations do not influence the activation of tight muscles.

Neuromuscular determinants of explosive torque: Differences among strength-trained and untrained young and older men.

This study compared the differences in neural and muscular mechanisms related to explosive torque in chronically strength-trained young and older men (>5 years). Fifty-four participants were allocated into four groups according to age and strength training level: older untrained (n = 14; 65.6 ± 2.9 years), older trained (n = 12; 63.6 ± 3.8 years), young untrained (n = 14; 26.2 ± 3.7 years), and young trained (n = 14; 26.7 ± 3.4 years). Knee extension isometric voluntary explosive torque (absolute and normalized as a percentage of maximal voluntary torque) was assessed at the beginning of the contraction (ie, 50, 100, and 150 ms-T50, T100, and T150, respectively), and surface electromyogram (sEMG) amplitude (normalized as a percentage of sEMG recorded during maximal voluntary isometric contraction) at 0-50, 50-100, and 100-150 time windows. Supramaximal electrically evoked T50 was assessed with octet trains delivered to the femoral nerve (8 pulses at 300 Hz). Voluntary T50, T100, and T150 were higher for trained than untrained in absolute (P < 0.001) and normalized (P < 0.030) terms, accompanied by higher sEMG at 0-50, 50-100, and 100-150 ms (P < 0.001), and voluntary T50/octet T50 ratio for trained. Greater octet T50 was observed for the young trained (P < 0.001) but not for the older trained (P = 0.273) compared to their untrained counterparts. Age effect was observed for voluntary T50, T100, and T150 (P < 0.050), but normalization removed these differences (P > 0.417). Chronically strength-trained young and older men presented a greater explosive torque than their untrained pairs. In young trained, the greater explosive performance was attributed to enhanced muscular and neural mechanisms, while in older trained to neural mechanisms only.

Short-term nutritional counseling reduces body mass index, waist circumference, triceps skinfold and triglycerides in women with metabolic syndrome.

BACKGROUND: It is recognized that the growing epidemic of metabolic syndrome is related to dietary and lifestyle changes. OBJECTIVE: The purpose of this study was to evaluate short-term application of nutritional counseling in women with metabolic syndrome. METHODS: This follow-up study was conducted from September to November 2008 with thirty three women > or =35 years old screened clinically for nutritional counseling. Dietary intake was reported, and biochemical and body composition measures were taken at baseline and after three months of follow-up. RESULTS: Of the 33 women evaluated, 29 patients completed the study. The prevalence of type 2 diabetes mellitus, hypertension, dyslipidemia, and obesity was high at 38%, 72.4%, 55.2%, and 75.8%, respectively. At the end of three-months of follow-up, a significant decline in body mass index, waist circumference, triceps skinfold, and triglycerides was observed, as was an increase in calcium and vitamin D intake. The multiple regression analysis showed that changes in body mass index, triceps skinfold, waist circumference and triglyceride levels after nutritional intervention were positively associated with changes in anthropometric (loss of body weight) and biochemical (decrease of TG/HDL-c ratio) parameters. Moreover, waist circumference changes were negatively associated with changes in calcium and vitamin D intake. CONCLUSION: Short-term nutritional counseling improved some factors of metabolic syndrome. Moreover, the increases in calcium and vitamin D consumption can be associated with the improvement in markers of metabolic syndrome.