*2.1. Information Sources and Search Strategy*

The initial search was performed on 20 August 2020, by using the following databases: Web of Science (all databases), Scopus, PubMed, PEDro, and Cochrane Library. Searches were conducted in English. The option "advanced searches" was chosen for searches in Web of Science, PubMed, and Scopus with regard to the articles' title, abstract, and keywords. A simple search was done in Cochrane library and PEDro. The Boolean operators used were "OR" within the construct, and "AND" between constructs. The following search terms were used:

(detraining OR inactivity) AND (balance OR **"**postural control**"** OR **"**postural stability**"**) AND (**"**fall risk**"** OR **"**falls risk**"** OR falling OR **"**fall rate**"**)

## *2.2. Eligibility Criteria and Study Selection*

Articles were eligible for inclusion in the current study according to the following criteria. Any type of intervention study was accepted in the review (e.g., randomized controlled trials, non-randomized controlled trials, pre-post studies with no control group). Only studies written in English were considered. In terms of outcomes, only studies that measured balance control in humans after a period of detraining were included. Here, we consider any study that reports on the effects of a sudden stop to exercise participation to fit this description. No limitations were set to the characteristics of the participants (e.g., young or old, athletes or sedentary), with the exception that clinical groups in which balance might be affected (e.g., amputations, neurological pathology, recent surgery) were excluded from the review. No limitations were set for the year of publishing.

In the first screening step, duplicates were removed using EndNote software. Further screening steps were performed after exporting to Microsoft Excel. Two authors were responsible for the screening process (S.M. and E.S.) and screened first the titles and later the abstracts and, finally, on the full text to sort out papers based on the inclusion criteria.

#### *2.3. Data Extraction*

Two authors were responsible for data extraction (S.M. and S.A.). The following factors were extracted for any study that was included in the present review: study design, training duration, detraining duration, measurement tools, groups, age of participants, study results with respect to effect of training, effect of detraining, conclusion, and future recommendations.
