Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2020 Apr;48(2):59-66.
doi: 10.1249/JES.0000000000000217.

Occupational Activities: Factors That Tip the Balance From Bone Accrual to Bone Loss

Mary F Barbe  1 , Steven N Popoff
Affiliations
Review

Occupational Activities: Factors That Tip the Balance From Bone Accrual to Bone Loss

Mary F Barbe et al. Exerc Sport Sci Rev. 2020 Apr.

Abstract

It is commonly assumed that beneficial adaptations in bone occur with vigorous exercise, yet any adaptive re/modeling in bone undergoing persistent overloading can be counteracted by superimposed inflammatory, compressive, and tensile loading-induced damage responses above thresholds of tissue fatigue failure and repair. This leads to a tenuous balance between achieving bone accrual and loss.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Schematic demonstrating that interactions of force, repetition, and duration of bone loading can elicit a pro-anabolic (bone accrual) response up to a point at which the combination of these factors exceeds a threshold (the transition region between the green and red zones), resulting in a net catabolic response due to tissue fatigue failure and damage (microcracks, osteocyte apoptosis). The point at which the threshold is crossed varies from one individual to another, and the factors that influence its location (e.g., age, sex, genetic background) should be considered in future studies. The figure was created in consultation with Susan Fecho, M.F.A., Barton College.
Figure 2
Figure 2
Image of rat performing the upper extremity reaching and grasping lever pulling task. A. Rat in an operant chamber with one limb extended into a portal located at shoulder height. B. Rat shown pulling on the lever bar, with digits four and five positioned in an ulnar position, indicative of ulnar deviation while pulling. C. Rat shown pulling in a neutral position. D. Rat retrieving a food reward.
Figure 3
Figure 3
A and B. MicroCT images of ulnar (U) and radius (R) of control, 18-wk LFHR task, and 18-wk HFHR task rats. A. Transaxial images of the distal metaphyseal ulna and radius. Note the reduced numbers of trabeculae in HFHR rat radius. B. Sagittal images. C. Microcracks in the radial trabeculae (after basic fuchsin staining) of 18-wk HFHR rats lead to increased osteocyte apoptosis, sclerostin, and RANKL, which decreased osteoblast and increased osteoclasts numbers, respectively, compared with controls (C). (Adapted from (51). Copyright © 2019 Elsevier. Used with permission.)
See this image and copyright information in PMC

References

    1. Bonewald LF. The amazing osteocyte. J. Bone Miner. Res. 2011; 26(2):229–38. - PMC - PubMed
    1. Santos L, Elliott-Sale KJ, Sale C. Exercise and bone health across the lifespan. Biogerontology. 2017; 18(6):931–46. - PMC - PubMed
    1. Wohl GR, Boyd SK, Judex S, Zernicke RF. Functional adaptation of bone to exercise and injury. J. Sci. Med. Sport. 2000; 3(3):313–24. - PubMed
    1. Romano A, Vigna L, Belluigi V, et al. Shift work and serum 25-OH vitamin D status among factory workers in northern Italy: cross-sectional study. Chronobiol. Int. 2015; 32(6):842–7. - PubMed
    1. Avin KG, Bloomfield SA, Gross TS, Warden SJ. Biomechanical aspects of the muscle-bone interaction. Curr. Osteoporos. Rep. 2015; 13(1):1–8. - PMC - PubMed

Publication types