Table 2.

Search strategy

Search #	Keywords	Terms and MeSH vocabulary
1	Microgravity	Microgravity OR spaceflight OR weightlessness
2	Musculoskeletal	Muscle OR bone OR musculoskeletal OR ‘skeletal muscle’
3	Countermeasure	Exercise OR training OR countermeasure
4	Combined search	1 AND 2 AND 3 1 AND 2 1 AND 3

Note. Medical Subject Headings (MeSH) as a comprehensive controlled vocabulary for the purpose of indexing journal articles and books in the life sciences were included in the search strategy. In the Pubmed advanced search builder either ‘Title/Abstract’ [tiab] was used.