In vitro modeling of human tibial strains during exercise in micro-gravity

Marc M. Peterman, Andrew J. Hamel, Peter R. Cavanagh, Stephen Jacob Piazza, Neil Sharkey

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

Prolonged exposure to micro-gravity causes substantial bone loss (Leblanc et al., Journal of Bone Mineral Research 11 (1996) S323) and treadmill exercise under gravity replacement loads (GRLs) has been advocated as a countermeasure. To date, the magnitudes of GRLs employed for locomotion in space have been substantially less than the loads imposed in the earthbound 1G environment, which may account for the poor performance of locomotion as an intervention. The success of future treadmill interventions will likely require GRLs of greater magnitude. It is widely held that mechanical tissue strain is an important intermediary signal in the transduction pathway linking the external loading environment to bone maintenance and functional adaptation; yet, to our knowledge, no data exist linking alterations in external skeletal loading to alterations in bone strain. In this preliminary study, we used unique cadaver simulations of micro-gravity locomotion to determine relationships between localized tibial bone strains and external loading as a means to better predict the efficacy of future exercise interventions proposed for bone maintenance on orbit. Bone strain magnitudes in the distal tibia were found to be linearly related to ground reaction force magnitude (R2 >0.7). Strain distributions indicated that the primary mode of tibial loading was in bending, with little variation in the neutral axis over the stance phase of gait. The greatest strains, as well as the greatest strain sensitivity to altered external loading, occurred within the anterior crest and posterior aspect of the tibia, the sites furthest removed from the neutral axis of bending. We established a technique for estimating local strain magnitudes from external loads, and equations for predicting strain during simulated micro-gravity walking are presented.

Original languageEnglish (US)
Pages (from-to)693-698
Number of pages6
JournalJournal of Biomechanics
Volume34
Issue number5
DOIs
StatePublished - May 2 2001

Fingerprint

Microgravity
Gravitation
Bone and Bones
Bone
Locomotion
Tibia
Exercise equipment
Maintenance
Orbit
In Vitro Techniques
Gait
Cadaver
Walking
Minerals
Signal Transduction
Loads (forces)
Orbits
Tissue
Research

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Orthopedics and Sports Medicine
  • Biomedical Engineering
  • Rehabilitation

Cite this

Peterman, Marc M. ; Hamel, Andrew J. ; Cavanagh, Peter R. ; Piazza, Stephen Jacob ; Sharkey, Neil. / In vitro modeling of human tibial strains during exercise in micro-gravity. In: Journal of Biomechanics. 2001 ; Vol. 34, No. 5. pp. 693-698.
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In vitro modeling of human tibial strains during exercise in micro-gravity. / Peterman, Marc M.; Hamel, Andrew J.; Cavanagh, Peter R.; Piazza, Stephen Jacob; Sharkey, Neil.

In: Journal of Biomechanics, Vol. 34, No. 5, 02.05.2001, p. 693-698.

Research output: Contribution to journalArticle

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