Evidence map›Paper›PMID 39632504›Full record

ArticleExperimental physiology2026

50% body weight loading reduces stature increases and lumbar disc expansion from 4 h hyper-buoyancy floatation versus 15 min sitting upright.

David Marcos-Lorenzo, Christina Lysandrou, Laura Sudres, Alfonso Gil-Martinez, Jaap Swanenburg, James Edward Clark, David Andrew Green

Abstract read
In one paragraph

Article in Experimental physiology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 3 papers.

0numbers the graph read from it
0cells of the map it votes in
3citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

3 citing papers in PubMed.

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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

7 authors.

David Marcos-LorenzoSchool of Medicine of Autonomous University of Madrid, Madrid, Spain.ORCID https://orcid.org/0000-0002-0132-6040
Christina LysandrouCentre of Human and Applied Physiological Sciences, King's College London, London, UK.
Laura SudresDepartment of Physiotherapy, Centro de Estudios Superiores La Salle, Madrid, Spain.ORCID https://orcid.org/0009-0000-2438-4975
Alfonso Gil-MartinezDepartment of Physiotherapy, Centro de Estudios Superiores La Salle, Madrid, Spain.ORCID https://orcid.org/0000-0003-0115-088X
Jaap SwanenburgIntegrative Spinal Research ISR, Department of Chiropractic Medicine, Balgrist University Hospital, Zurich, Switzerland.ORCID https://orcid.org/0000-0002-1754-9206
James Edward ClarkCentre of Human and Applied Physiological Sciences, King's College London, London, UK.ORCID https://orcid.org/0000-0001-7574-2162
David Andrew GreenCentre of Human and Applied Physiological Sciences, King's College London, London, UK.ORCID https://orcid.org/0000-0001-8634-8769

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Microgravity is associated with stature increases, back pain and post-flight intervertebral disc (IVD) herniation. This study aims to determine whether 30 s seated 50% body weight (BW) axial loading is comparable to 15 min sitting upright in 1 g upon changes in stature, anterior lumbar IVD height (via ultrasound), passive vertebral stiffness (VS), and back pain induced by 4 h hyper-buoyancy floatation (HBF) unloading. Sixteen (seven male) healthy volunteers had stature, lumbar IVD height (L2-S1), passive VS (C1-L5) and back pain assessed before and following 4 h HBF, and immediately after participants performed a 30 s seated squat with 50% of their BW or 15 min sitting upright. Four hours of HBF unloading induced significant increments in stature (+1.6 ± 0.5 cm; P < 0.001), IVD height (L2-L3: P = 0.002; L3-L4: P < 0.001; L4-L5: P = 0.013; L5-S1: P < 0.001) and back pain (2.90 ± 1.26; P < 0.001) with no differences between 1 and 1.5 BW. Stature, IVD height increments and back pain were similarly attenuated in both reloading groups. Passive VS was unchanged by 4 h HBF or reloading. HBF-induced back pain positively correlated with stature (P = 0.01) and lumbar IVD height changes (L2-L3: P = 0.03; L3-L4: P = 0.01; L5-S1: P = 0.02). Four hours of HBF increased stature, lumbar IVD height and induced moderate back pain that were similarly (albeit not entirely) ameliorated by both 15 min upright sitting and 30 s of 50% BW axial loading, with no changes in passive VS observed. IVD geometric changes appear key to space adaptation back pain and stature increments that can be rapidly modulated by brief periods of axial loading.

Indexed as

Body HeightBody WeightIntervertebral DiscLumbar VertebraeWeight-BearingAdultBack PainFemaleHumansIntervertebral Disc DisplacementMalePostureSitting PositionWeightlessnessYoung Adultback painintervertebral discreloadingunloading

Identifiers

PMID39632504
PMCPMC13394184

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.