Böcker's 60-day/~80-day dose-equivalence conclusion is derived entirely from Böcker's own study arms and one external dataset — Stavnichuk's pooled rate is not an input at any step

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Böcker et al. 2026's dose-equivalence conclusion — that 60 days of bed rest models six months of spaceflight bone loss, while muscle needs ~80 days — is derived in two different ways, and neither touches Stavnichuk's pooled −0.8%/month lower-limb rate.

For bone, the figure comes from a direct within-study statistical comparison: Böcker's own 13-subject spaceflight arm against its own 11-subject, 60-day, no-countermeasure bed-rest arm, on cross-calibrated pQCT (claim-matched-pqct-comparison-finds-bone-loss-comparable-while-muscle-loss-under-runs). For muscle, the ~80-day figure is a separate extrapolation that does not even use that comparison: "Based on these findings, we aimed to estimate the required bed rest duration to elicit comparable muscle loss to that observed after spaceflight," fitting a logarithmic function that pulls in a third dataset alongside its own 60-day arm (Fig. 5 pools the LTBR and RSL control groups) — "we used data of the control group without any physical training from the LTBR study (long term bed rest: 90 days of 6° head-down tilt bed rest), which had a bed rest duration of 90 days." (LTBR is Jörn Rittweger's own 2005 study, Böcker's reference 27.)

Stavnichuk's meta-analysis appears once in the whole paper, as reference 17, cited only for the generic background sentence that musculoskeletal adaptations "do still occur" despite countermeasures — never as an input, benchmark, or check for either dose-equivalence calculation. This extends the evidentiary gap claim-bocker-cites-stavnichuk-without-testing-its-pooled-rate already established for Böcker's magnitude-equality claim ("bone loss was comparable") to Böcker's duration-equivalence claim as well: both of Böcker's headline framings of the bed-rest analog are self-contained, and Stavnichuk's number is cover for a sentence about countermeasures, not evidence for either conclusion.