Influence of aging on segmental angular momenta during voluntary stepping J. Begue a , N. Peyrot b,a , A. Lesporta , N A. Turpina , B. Watier c , G. Dalleaua and T. Caderbya a Laboratoire IRISSE, UFR des Sciences de l’Homme et de l’Environnement, Universite de la Reunion, Le Tampon, Ile de la Reunion; b Laboratoire Motricite, Interactions, Performance, MIP, Le Mans Universite, Le Mans Cedex 9, France; c LAAS- CNRS, Universite de Toulouse, CNRS, UPS, Toulouse, France 1. Introduction Whole-body angular momentum (WBAM) appears to be a tightly controlled variable by humans to safely and efficiently perform daily motor tasks. During walking, it has been shown that humans tend to min- imize WBAM, i.e. keep this quantity close to zero (Herr and Popovic 2008). This is achieved through segment-to-segment angular momentum cancellations, suggesting fine regulation and coordination of rota- tions of all body segments. Interestingly, it has been reported that a higher WBAM range during walking was associated with a lower clinical balance score, i.e. poor balance control, in people with mobility impairments and risk of fall- ing (Vistamehr et al. 2016). Recently, Begue et al. (2019) revealed that the control of WBAM during volitional stepping initiation was altered by normal aging. Compared to younger adults (YA), older adults (OA) exhibited smaller WBAM ranges during the double support phase and conversely, higher WBAM ranges during the step execution phase, which could impose a higher challenge for balance control and a potentially higher risk of falling. However, in this pre- vious study, angular momenta of individual body seg- ments were not investigated. Consequently, it remains unclear how aging alters segmental angular momenta during stepping. Thus, the current study aimed to determine effects of aging on segmental angular momenta and on their contribution to WBAM during stepping. We hypothe- sized that OA would have a greater WBAM compared to YA during stepping due to larger segmental angu- lar momenta.