Nine parallel-group RCTs (with 12 study groups) were included in the review (n=341 in studies, n=290 included in analyses).
The mean drop-out rate was 15% (range: 0 to 37).
The funnel plots for systolic blood pressure and diastolic blood pressure were slightly asymmetrical with smaller changes in net blood pressure in larger studies, but Kendall's tau statistics were not significant (p=0.27 and p=0.73, respectively).
There was no statistically significant heterogeneity for the meta-analysis of either systolic blood pressure or diastolic blood pressure.
When weighting was applied using the inverse of the variance, resistance training was associated with a significant decrease in systolic blood pressure (-6.0 mmHg, 95% CI: -10.4, -1.6, p<0.01) and diastolic blood pressure (-4.7 mmHg, 95% CI: -8.1, -1.4, p<0.01) compared with control. When weighting was applied using the sample size, resistance training was associated with a significant decrease in diastolic blood pressure compared with control (-3.5 mmHg, 95% CI: -6.1, -0.9, p<0.01), but there was no significant difference between treatments in systolic blood pressure (-3.2 mmHg, 95% CI: -7.1, 0.7, p=0.10).
In the subgroup analyses, only duration of follow-up appeared to be significantly associated with changes in blood pressure. Studies with longer follow-up (>15 weeks) showed smaller changes in systolic blood pressure (p<0.01) and diastolic blood pressure (p<0.05) than studies lasting less than 15 weeks.
The results for the other outcomes were reported in the paper.