Associations Between Types of Balance Performance in Healthy Individuals Across the Lifespan: A Systematic Review and Meta-Analysis.

The objective of this systematic review and meta-analysis was to quantify and statistically compare correlations between types of balance performance in healthy individuals across the lifespan. Literature search was performed in the electronic databases PubMed, Web of Science, and SPORTDiscus. Studies were included if they investigated healthy individuals aged ≥6 years and reported measures of static/dynamic steady-state, proactive, and/or reactive balance. The included studies were coded as follows: age group, gender, and balance type, test, parameter. Pearson's correlation coefficients were extracted, transformed (i.e., Fisher's z-transformed -value), aggregated (i.e., weighted mean -value), back-transformed to -values, classified according to their magnitude, and statistically compared. The methodological quality of each study was assessed using the Appraisal tool for Cross-Sectional Studies. We detected twenty-six studies that examined associations between types of balance and exclusively found small-sized correlations, irrespective of the age group considered. More specifically, the weighted mean -values amounted to 0.61 (back-transformed -value: 0.54) in old adults for the correlation of dynamic steady-state with proactive balance. For correlations between dynamic and static steady-state balance, the weighted mean -values amounted to 0.09 in children (-value: 0.09) and to 0.32 in old adults (-value: 0.31). Further, correlations of proactive with static steady-state balance revealed weighted mean -values of 0.24 (-value: 0.24) in young adults and of 0.31 (-value: 0.30) in old adults. Additionally, correlations between reactive and static steady-state balance yielded weighted mean -values of 0.21 (-value: 0.21) in young adults and of 0.19 (-value: 0.19) in old adults. Moreover, significantly different correlation coefficients ( = 8.28, < 0.001) were only found for the association between dynamic and static steady-state balance in children ( = 0.09) compared to old adults ( = 0.31). Lastly, we detected trivial to considerable heterogeneity (i.e., 0% ≤ I ≤ 83%) between studies. Our systematic review and meta-analysis showed exclusively small-sized correlations between types of balance performance across the lifespan. This indicates that balance performance seems to be task-specific rather than a "general ability." Further, our results suggest that for assessment/training purposes a test battery/multiple exercises should be used that include static/dynamic steady-state, proactive, and reactive types of balance. Concerning the observed significant age differences, further research is needed to investigate whether they are truly existent or if they are caused by methodological inconsistencies.