Sibonga et al. 2019 reports that in-flight resistive exercise (ARED) prevented cortical vBMD decline at the femoral neck but did not prevent hip trabecular vBMD loss

space-medicineaerospace-physiologybone-densitytrabecular-corticalcountermeasuresared

Sibonga et al.'s 2019 Bone paper (Bone 128:112037) — Böcker et al. 2026's reference 23 — recruited ten ISS astronauts who used the Advanced Resistive Exercise Device (ARED) without drug administration, and compared them both to an earlier cohort flown before in-flight ARED access ("Pre-ARED", n = 14–18) and to a previously reported group who combined ARED with the bisphosphonate alendronate. Its published abstract states that "[r]esistive exercise in the ARED group did not prevent declines in hip trabecular vBMD, but prevented reductions in cortical vBMD of the femoral neck." The same countermeasure, in the same astronauts, thus succeeded at the cortical compartment and failed at the trabecular one. The authors' own conclusion is that the trabecular compartment needs a pharmacological addition to hold: a bisphosphonate combined with resistive exercise "enhances the preservation of bone mass because of the added suppression of bone resorption in trabecular bone compartment not evident with ARED alone."

This is one of two spaceflight-side sources (claim-vico-2017-post-spaceflight-cortical-recovers-trabecular-does-not is the other) that Böcker cites for the spaceflight-trabecular half of the compartment dissociation (claim-bocker-refs-support-bedrest-cortical-spaceflight-trabecular-dissociation). Note that "more affected" here means which compartment resists a countermeasure — a different sense than the mass loss measured on the bed-rest side (claim-rittweger-2010-bed-rest-tibial-loss-almost-entirely-cortical) and than the failure to recover measured by Vico. The direction lines up across all three, but they are not a like-for-like magnitude comparison, and the full text (which would carry the percent-loss numbers) was paywalled at capture, so this rests on the authors' verbatim published abstract only. First author Jean Sibonga is NASA Johnson Space Center's bone-loss lead.

Correction history.

• 2026-08-23 (scheduled cross-model audit, claude-opus-5 auditing claude-opus-4-8) — Three changes. The note's central claim was confirmed verbatim against the authors' published abstract and is unchanged.
  1. Unsupported inference removed. The first paragraph ended: "…a demonstration that trabecular bone is the more vulnerable compartment during spaceflight, independent of exercise intensity." The study did not vary exercise intensity — it ran one ARED protocol — so nothing in it licenses an "independent of exercise intensity" conclusion. Replaced with what the authors do conclude: that trabecular preservation required a bisphosphonate added to resistive exercise, quoted from the abstract.
  2. Broken wikilink repaired. The note linked [[entity-advanced-resistive-exercise-device]], which does not exist anywhere in 40-entities/. De-linked to plain text rather than minting an entity page outside the entity-promotion test.
  3. Cohort description corrected. Was: "compared ISS astronauts using the ARED, with and without the bisphosphonate alendronate, against an earlier 'Pre-ARED' cohort," which implies one study population split by drug. The abstract describes ten newly recruited ARED-only astronauts compared against a Pre-ARED cohort (n = 14–18) and against the previously reported Bis+ARED group. Group structure and journal citation now stated. (Pointer: Europe PMC REST record for PMID 31400472, https://www.ebi.ac.uk/europepmc/webservices/rest/search?query=ext_id:31400472%20AND%20src:med&resultType=core&format=json; Bone 128:112037.)