A review on strength exercise-induced muscle damage: applications, adaptation mechanisms and limitations.

This study aims to review the main aspects that induce muscle damage, and to discuss the adaptations of this phenomenon, applications and limitations of this study area. Damage induced by strength training has been utilized for two purposes: 1) verification of the recovery period required between training sessions, which has a direct influence on designing exercise programs; and 2) as indication for higher training intensity, mainly in studies on the "repeated bout effect". There is some speculation about the role of muscle damage in inducing hypertrophy. However, studies demonstrate that exercise-induced muscle damage may not be a consistent indicator of higher chronic hypertrophic response, because hypertrophy also occurs in training strategies with very low mechanical overloads. In addition, aerobic exercise, also induces muscle damage, exhibits no hypertrophic response after training. The remodeling process induced bay muscle damage promotes alterations to strength x length relationship for stretched positions, indicating an increased number of sarcomeres in series, due to strength exercises. Therefore, the study on strength exercise-induced damage seems to be adequate for implementing adequate rest periods to recovery from different sessions of strength training, and not to suggest chronic hypertrophy.

Effects of resistance training on the lipid profile in obese women.

AIM: The aim of the present study was to analyze the effects of resistance training in groups (with music) on the lipid profile in obese women. METHODS: The sample was composed of 28 sedentary obese women. Of these, 13 were submitted to the resistance training in group program (GT) and 15 took part in a control group (GC). The training lasted for 9 weeks, with three weekly sessions. The classes emphasized resistance training through the performance of 10 localized exercises. The analysis evaluated the following variables: total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides (TG) and the TC/HDL ratio in the pre and post-training periods in both groups. The data was analyzed using Anova for repeated measures with one factor, adopting P<0.05. RESULTS: The study found significant differences for the training group between the pre- and post-training period in all the analyzed variables, except for the TG. In contrast, for the control group there was no significant difference between the pre and post-training period in any of the variables, except for the TG in which we found a statistically significant increase. The reductions were from 200.62 ± 39.11 mg·dL-1 to 184.92 ± 28.62 mg·dL-1 for TC; from 137.69 ± 32.09 mg·dL-1 to 110.31 ± 21.92 mg·dL-1 for LDL; from 4.48 ± 1.00 to 3.70 ± 0.90 for the TC/HDL ratio and the improvement in the HDL was from 46.23 ± 12.04 mg·dL-1 to 53.15 ± 16.83 mg·dL-1. CONCLUSION: Thus, it was concluded that the resistance training in groups with music was effective since it provided beneficial modifications to the lipid profile, which may result in lower risk of coronary arterial diseases in the obese female population.

Salivary hormonal responses to resistance exercise in trained and untrained middle-aged men.

AIM: The aim of the present study was to investigate if there are differences in salivary hormonal responses to resistance exercise between long-term strength-trained and untrained men. METHODS: Twenty-eight subjects were recruited to this study, matched into a strength-trained group (SG, N=13) and an untrained group (UG, N=15). Upper and lower body absolute muscle strength was measured through the one-repetition maximum (1-RM) test. Saliva samples were collected at rest and after a resistance exercise protocol (REP) with intensity relative to 1-RM values. With these samples, testosterone (TES), dehydroepiandrosterone (DHEA) and cortisol (COR) were determined. RESULTS: SG subjects demonstrated significantly higher values in all muscle strength variables. While a significant increase in TES after REP was found in the SG (0.114 + or - 0.1 vs. 0.15 + or - 0.09 pg/mL, P<0.05), no differences were observed in the UG (0.144 + or - 0.1 vs. 0.17 + or - 0.1 pg/mL). In both groups, there were increases in salivary COR (SG: 1.4 + or - 0.6 vs. 2.06 + or - 1; UG: 1.5 + or - 0.8 vs. 2.3 + or - 1.2 ug/dL, P<0.05) and DHEA (SG: 0.6 + or - 0.3 vs. 0.9 + or - 0.6; UG: 0.65 + or - 0.3 vs. 0.97 + or - 0.7 ng/dL, P<0.05). CONCLUSIONS: These results suggest the possible presence of adaptation of TES responses to resistance exercise in long-term strength-trained men, with these subjects presenting higher responses to the same stimulus, compared with untrained subjects, while no such adaptation was seen at the adrenocortical level in these subjects as the responses observed were similar in both groups.