Effects of unweighting and speed on in-shoe regional loading during running on a lower body positive pressure treadmill. Issue 10 (16th July 2015)

• Record Type: Journal Article
• Authors: Smoliga, James M.; Wirfel, Leah Anne; Paul, Danielle; Doarnberger, Mary; Ford, Kevin R.
• Is Part Of: Journal of biomechanics. Volume 48:Issue 10(2015)
• Page Start: 1950
• Page End: 1956
• Publication Date: 2015-07-16
• Subjects: Animal mechanics -- Periodicals; Biomechanics -- Periodicals; Biomechanics -- Periodicals; Mécanique animale -- Périodiques; Biomécanique -- Périodiques; Electronic journals; 571.4305
• DOI: 10.1016/j.jbiomech.2015.04.009
• Languages: English
• ISSNs: 0021-9290

Abstract

<abstract abstract-type="author" id="ab0010"> <title id="sect0005">Abstract</title> <sec> <p id="sp0055">The purpose of this study was to determine how unweighted running on a lower body positive pressure treadmill (LBPPT) modifies in-shoe regional loading. Ten experienced runners were fit with pressure distribution measurement insoles and ran at 100%, 120%, and 140% of self-reported easy training pace on a LBPPT at 20%, 40%, 60%, 80%, and 100% body weight percentage settings (BW<sub>Set</sub>). Speeds and BW<sub>Set</sub> were in random order. A linear mixed effect model (<italic>p</italic><0.05 significance level) was used to compare differences in whole foot and regional maximum in-shoe plantar force (<italic>F</italic><sub>MAX</sub>), impulse, and relative load distribution across speeds and BW<sub>Set</sub>. There were significant main effects (<italic>p</italic><0.001) for running speed and BW<sub>Set</sub> for whole foot <italic>F</italic><sub>max</sub> and impulse. The model revealed 1.4% and 0.24% increases in whole foot <italic>F</italic><sub>MAX</sub> (times body weight) and impulse, respectively, for every unit increase in body weight percentage. There was a significant main effect for BW<sub>Set</sub> on <italic>F</italic><sub>max</sub> and relative load (<italic>p</italic><0.05) for each of the nine foot regions examined, though four regions were not different between 80% and 100% BW<sub>Set</sub>. There was a significant (<italic>p</italic><0.001) main effect for BW<sub>Set</sub> on forefoot to rear foot relative load. Linear relationships were found between increases in BW<sub>Set</sub> and increases in-shoe <italic>F</italic><sub>max</sub> and impulse, resulting from regional changes in foot pressure which represent a shift towards forefoot loading, most evident <80% BW<sub>Set</sub>. Estimating in-shoe regional loading parameters may be useful during rehabilitation and training to appropriately prescribe specific speed and body weight levels, without exceeding certain critical peak force levels while running.</p> </sec> </abstract>