Effects of aerobic, resistance, and combined training on endothelial function and arterial stiffness in older adults: study protocol for a systematic review and meta-analysis

Table 2 Interpretation of heterogeneity results

Interpretation of I²
0 to 40%: might not be important
30 to 60%: may represent moderate heterogeneity^a
50 to 90%: may represent substantial heterogeneity^a
75 to 100%: considerable heterogeneity^a

^aThe importance of the value of I² depends on the magnitude and direction of effects and the strength of evidence for heterogeneity (I² confidence interval: uncertainty of the value of I² is substantial when there is a small number of studies)

ISSN: 2046-4053