Background: Deficit in elderly muscle strength results in reduction of functional performance in activities of daily living. Therefore, resistance training (RT) is a effective
strategy to change this situation. Training intensity seems to have a great importance attenuating these consequences. Therefore, the aim of the present study was to investigate the
intensity-dependence for upper-body functional performance improvement in older adults.
Methods: Eighteen untrained older adults volunteers (9 men and 9 women) were randomized in two groups: HI-High intensity (n=9, 61±6 years; 77±12kg; 1.66±0.1m) and LI-Low Intensity
(n=9, 66±6 years; 77±12kg; 1.65±0.1m). Subjects were tested and retested before the RT period (T1) for baseline values. RT effects were assessed after 12 (T2) and 24 (T3) sessions. On each test days,
a five-repetition maximum (5-RM) for seated row; hand grip strength test (HGS) and local muscular endurance for elbow flexors (LME) were performed. The subjects trained with seated row for 24
sessions, 3 times per week with at least 48 hours of rest between sessions. Groups trained with different intensities ((p<0,001) and equal volumes (HI- 3 x 5 RM, 83% 1-RM estimate and LI 1 x 15 RM,
66% 1-RM estimate), where the HI group has a rest interval of 120s between sets. Before each training session, the groups performed a specific warm-up, consisting of 10 repetitions with approximately
50% of the resistance used in the training session. The training resistance was increased by 5–10% for the next session when subjects were able to perform more than repetitions scheduled for the
session. Independent sample T-test was used to verify differences between groups for intensity of 1-RM estimate. 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 significant (p<0.05).
Results: Baseline values were similar between groups (p>0.05). After 24 sessions of RT the LME significantly increased for LI group (20±0.7) compared with HI group (17±0.7), p=0,023.
In other way, 5-RM (48±4 and 51±4; p=0.57) and HGS (33±3 and 34±3; p=0.91) did not show difference between groups. When compared moment within of the groups, both showed the same results, in LME T3
was different for T1 (p=0.006) and T2 (=0.020), however for 5-RM, T1 was different for T2 and T3 (p<0.001), as well as, T2 was for T3 (p<0.001). The HGS no showed changes during three moment for both
Conclusions: The intensity seems to make no difference to improve upper body maximum strength (5-RM) in untrained older adults, because both intensities showed improvement over time.
LME showed better adaptation for LI group because of training specificity (1 x 15). Finally, different intensities do not influence change in HGS.