Body segment inertial parameters of elite swimmers: analysis using DXA and estimation of errors from indirect estimation methods

Marcel Rossi

    Research output: ThesisMaster's Thesis

    329 Downloads (Pure)


    The present study proposed a new method to compute body segment inertial parameters (BSIPs) using DXA. This new approach essentially co-registers the areal density data with grayscale images, which enables a relationship between the pixel colour intensity and the mass recorded to be established for the referred area. BSIPs could then be calculated for various segments. Using this method, BSIP were then measured in elite male swimmers, elite female swimmers and young adult Caucasian males. The study then compared BSIPs derived from the proposed technique against five previously used indirect BSIP estimation methods across all three populations. Ten elite male swimmers, eight elite female swimmers, and ten young adult Caucasian males had their whole body mass calculated from the relationship found between pixel colour intensity and areal density. The calculated masses were compared against the criterion value obtained from the DXA scanner by percentage root mean square error (%RMSE). Subjects were also scanned with 3D surface scans to enable mapping of key anthropometric variables necessary for calculation of BSIPs when using the indirect estimation methods. The mass, centre of mass (COM) and moment of inertia (MOI) about the sagittal axis of seven body segments (head, trunk, head combined with trunk, upper arm, forearm, thigh & shank) were computed from the proposed DXA method for each group. Differences between participant groups were assessed using the analysis of variance (ANOVA). When applying the five indirect estimation methods to each of the three referred populations, errors were assessed, using the BSIPs gathered with DXA as criterion, by calculating the %RMSE and searching for significant differences in absolute percentage errors for all BSIPs. Computing BSIPs using the proposed method yielded %RMSE of less than 1.5%. This agreed with the accuracy of previous DXA BSIP estimation methods.
    Original languageEnglish
    Publication statusUnpublished - 2012


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