Background: Resistance training (RT) is widely used to improve elderly muscle strength. In young, RT with sets to concentric failure shows great efficiency in strength and muscle mass
increase. Before investigating the effects of concentric failure method in elderly, more information about how time-course of recovery may improve training prescription quality is required. The aim of
the present study was to investigate the time-course of recovery in elderly after a single session of RT with two different intensities.
Methods: Twenty-two volunteers (15 men and 7 women) were randomized in two groups: G70 (n=11, 66±5 years; 75±12 kg, and 32±7% of body fat) and G95 (n=11, 67±5 years; 74±16 kg, and
31±7% of body fat). Subjects reported to the lab on four occasions, with at least 48 hours of interval between days. In the first visit, body composition was measured using DXA. During the following
three visits, subjects were familiarized, tested and retested to obtain baseline values for a five-repetition maximum (5-RM) (horizontal leg press and seated knee flexor) and isometric peak torque
(PT) during knee extension (isokinetic dynamometer). Three days after the retest, subjects performed a single RT session at intensity corresponding to 70% (G70) and 95% (G95) of 5-RM. Both groups
performed 3 sets to concentric failure with 2 min rest period between sets and exercises. After exercise (0 hours) and at 24, 48, and 72 hours PT was evaluated. Relative PT for each subject was
expressed as a percentage of the respective baseline value for 0, 24, 48, and 72 hours. Independent sample T test was used to verify differences between groups for 5-RM and PT at baseline. All
comparisons were analyzed by means of two-way ANOVA analysis of variance for repeated measures (group x time). Post-hoc was performed using Bonferroni corrected when main effects or interactions were
Results: PT baseline values were similar between groups (p>0.05). There was interaction between group x time (p=0.014). At 0 and 72 hours, G70 and G95 did not show difference (83±6
and 86±6%, p=0.282 and 103±9 and 99±9%, p=0.230, respectively). However, at 24 (100±5 and 93±5%, respectively; p=0.01) and 48 hours (103±8 and 95±5%, respectively; p=0.007) was observed difference.
When compared moment within groups, PT for G70 was lower at 0 (p<0.001), 24 (p<0.001), 48 (p<0.001), and 72 hours (p<0.001) compared to baseline, whereas for G95 was lower at 0 (p<0.001), 24 (p=0.01),
and 48 hours (p=0.029) compared to baseline. Moreover, PT at 0 hours was lower than 48 (p=0.042) and 72 hours (p=0.038), but no difference was observed between 72 hours and baseline (p>0.05).
Conclusions: RT prescription in elderly must consider different recovery period according to training intensity.