Exploratory Analysis of Unstable Surface Training: A Systematic Review and Meta-Analysis for Chronic Ankle Instability.
Shuang Liu, Bo Gou, Zhiguang Zhao and 1 others
PMID 39822207WHAT IT FOUND
Balance training on wobble boards, BAPS boards and similar unstable surfaces improved reach distance on most directions of the Star Excursion Balance Test and two single-leg balance tests in people with chronic ankle instability.
Hopping tests did not improve. The authors call the results preliminary.
Key findings
01Pooled results from 5 to 8 trials favoured unstable surface training over control for reach distance in the posterolateral, posteromedial, anteromedial and medial directions of the Star Excursion Balance Test (mean differences 5.80, 6.24, 7.25 and 9.11). The posterolateral result lost significance when two of the trials were removed from the analysis.
02There was no significant difference between groups for the anterior direction of the Star Excursion Balance Test (mean difference 3.22; P=.10), the side-hop test (mean difference -1.94; P=.19) or the figure-of-8 hop test (mean difference -0.97; P=.18).
03Static balance tests favoured unstable surface training (time-in-balance mean difference 8.45; P=.02, foot-lift mean difference -1.39; P=.01), but the significance of both changed when individual trials were removed, and the authors say more evidence is needed.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
Only 9 trials met the criteria, and most were small: 308 patients in total across all trials. The trials differed in who they recruited, what unstable surface they used and how long they trained, and several pooled analyses showed large differences between trials (one as high as 88%). Methodological quality was only fair overall: PEDro scores ranged from 4 to 7 with a mean of 5.56, five trials rated good and four rated fair. No trial blinded participants or therapists, and several were unclear about how participants were allocated to groups. Removing individual trials changed whether the results stayed significant for the posterolateral Star Excursion Balance Test direction and both static balance tests, so those findings are not stable. With fewer than 10 trials per outcome, the reviewers could not check for publication bias, so unpublished negative trials may be missing. Seven of the nine control groups received no intervention at all, so most comparisons say nothing about how unstable surface training compares with another active programme. Programmes lasted only 4 to 6 weeks, so nothing is known about whether any balance gains last, or about the best dose. The Star Excursion Balance Test was pooled in only 5 of its 8 directions, because three directions were measured in a single trial. One trial's data had to be read off a line chart with digitizing software, and posteromedial data missing from another trial were requested from its authors but never supplied.
Declared interests
The authors state they have no financial or nonfinancial disclosures to make in relation to this project. No funder or sponsor is reported.
The easy way to misread this
Do not read this as unstable surface training beating other treatments. Seven of the nine control groups did no training at all, so most of the pooled comparisons are against doing nothing, and the authors describe the review as exploratory with preliminary findings that should not be considered conclusive.
Summarised by AI from the full paper, without a clinician reviewing it. Check it against the source before it changes what you do. Read it on PubMed →