Kinetics and kinematics of prepubertal children participating in osteogenic physical activity Public Deposited

http://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/gq67jv80c

Descriptions

Attribute NameValues
Creator
Abstract or Summary
  • Introduction: Recent reports in exercise related bone research have shown increased bone mineral content (BMC) at the femoral neck for prepubescent children participating in exercise programs consisting of repeated drop landings from a height of 61 cm. Increases in BMC from this type of exercise are believed to be the result of both high rate and magnitude of loading at the proximal femur. However, the dynamic characteristics associated with these landings in children have not been studied. Purpose: To describe the dynamic characteristics of children during landing and to quantify the forces associated with an activity associated with increases in bone mass. Methods: 13 prepubescent children (males=8, females=5, age 9.3 ± 0.7 years) who had previously completed drop landings over a 7 month period as part of an exercise intervention to increase bone mass participated in this research. Each subject performed 100 drop landings onto a force plate from a height of 61 cm. Ground reaction forces and two-dimensional kinematic data were recorded. Hip joint reaction forces were calculated using inverse dynamics based on a four segment rigid body model. Vertical ground reaction force and displacement data were fit to two single degree of freedom models, the Voigt and standard linear solid (SLS). The goodness of fit was quantified using the standard deviation of the error (SDE) between the experimental and the predicted data. Results: Peak vertical ground reaction forces were 8.5 ± 2.2 (mean ± SD) body weights (BW) while hip joint reactions were 6.0 ± 1.8 BW. Loading rates for ground reaction forces during initial impact were in excess of 470 BW/s. Across 100 jump trials, ground reaction forces changed significantly for 5 subjects (4 increase, 1 decrease, p<0.05) but were unchanged as a group. The SLS and Voigt models replicated the displacement traces well (SDE=0.003 m and 0.001 m respectively). However, in fitting force data, the SLS outperformed the Voigt model (SDE=580 N and 493 N respectively), but slightly under-predicted peak forces by 13%. Conclusion: Comparing force characteristics from drop landing to force characteristics known to be osteogenic, we can see how drop landings contribute to the osteogenic stimulus. The models used to represent children during drop landing closely fit displacement data, but did not replicate the time history of the impact force peaks thought to be important to osteogenesis. Quantification of exercises known to increase bone mass provides a basis on which to develop and implement additional exercise interventions for the purpose of increasing bone mass.
Resource Type
Date Available
Date Copyright
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Committee Member
Academic Affiliation
Non-Academic Affiliation
Subject
Rights Statement
Peer Reviewed
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome, 8-bit Grayscale) using ScandAll PRO 1.8.1 on a Fi-6670 in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR.
Replaces
Additional Information
  • description.provenance : Submitted by John Valentino (valentjo@onid.orst.edu) on 2012-08-29T20:52:10Z No. of bitstreams: 1 BauerJeremyJ2000.pdf: 3000308 bytes, checksum: d6a4bc6c7851ebab239fe88f6bd840c0 (MD5)
  • description.provenance : Made available in DSpace on 2012-08-30T18:59:38Z (GMT). No. of bitstreams: 1 BauerJeremyJ2000.pdf: 3000308 bytes, checksum: d6a4bc6c7851ebab239fe88f6bd840c0 (MD5) Previous issue date: 2000-04-27
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2012-08-30T18:57:13Z (GMT) No. of bitstreams: 1 BauerJeremyJ2000.pdf: 3000308 bytes, checksum: d6a4bc6c7851ebab239fe88f6bd840c0 (MD5)
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2012-08-30T18:59:38Z (GMT) No. of bitstreams: 1 BauerJeremyJ2000.pdf: 3000308 bytes, checksum: d6a4bc6c7851ebab239fe88f6bd840c0 (MD5)

Relationships

In Administrative Set:
Last modified: 08/20/2017

Downloadable Content

Download PDF
Citations:

EndNote | Zotero | Mendeley

Items