Effect of resistance training with different frequencies and detraining on muscular strength and oxidative stress biomarkers in older women.Age (Dordr). 2015 Oct; 37(5):104.A
The aim of this study was to compare the effect of resistance training (RT) performed with different frequencies followed by a detraining period on muscular strength and oxidative stress (OS) biomarkers in older women. Twenty-seven physically independent women (68.8 ± 4.8 years, 69.1 ± 14.3 kg, 156.0 ± 6.5 cm, and 28.3 ± 4.9 to kg.m(-2)) were randomly assigned to perform a RT program for 2 or 3 days per week (G2X = 13 vs. G3X = 14) for 12 weeks followed by 12 weeks of detraining period. One repetition maximum (1RM) tests were used as measures of muscular strength (three exercises, three attempts for each exercise, 3-5 min of rest between attempts, and 5 min of rest between exercises). Advanced oxidized protein products (AOPP) and total radical-trapping antioxidant parameter (TRAP) were used as oxidative stress indicators. Both groups increased muscular strength after 12 weeks of training (P < 0.05) in chest press (G2X = +11.9 % vs. G3X = +27.5 %, P < 0.05), knee extension (G2X = +18.4 % vs. G3X = +16.7 %, P > 0.05), and preacher curl (G2X = +37.6 % vs. G3X = +36.7 %, P > 0.05). On the other hand, 12 weeks of detraining were not sufficient to eliminate the major effects produced by RT on muscular strength, although a significant decrease (P < 0.05) has been observed for chest press (G3X = -9.1 % vs. G2X = -10.2 %, P > 0.05), knee extension (G2X = -14.9 % vs. G3X = -12.1 %, P > 0.05), and preacher curl (G2X = -20.5 % vs. G3X = -17.4 %, P > 0.05). Pre- to post-training, both groups showed significant (P < 0.05) increases in TRAP (G2X = +6.9 % vs. G3X = +15.1 %) with no statistical significant difference between the groups (P > 0.05), and the scores remained elevated compared to pre-training after 12 weeks of detraining. AOPP was not changed by RT or detraining (P > 0.05). The results suggest that a 12-week RT program with a frequency of 2 days per week may be sufficient to improve muscular strength and OS in older women and detraining for 12 weeks does not completely reverse the changes induced by RT.