title: Neuromuscular electrical stimulation leads to physiological gains enhancing postural balance in the pre-frail elderly.
abstract: Physiological aging leads to a progressive weakening of muscles and tendons, thereby disturbing the ability to control postural balance and consequently increasing exposure to the risks of falls. Here, we introduce a simple and easy-to-use neuromuscular electrical stimulation (NMES) training paradigm designed to alleviate the postural control deficit in the elderly, the first hallmarks of which present as functional impairment. Nine pre-frail older women living in a long-term care facility performed 4 weeks of NMES training on their plantarflexor muscles, and seven nontrained, non-frail older women living at home participated in this study as controls. Participants were asked to perform maximal voluntary contractions (MVC) during isometric plantarflexion in a lying position. Musculo-tendinous (MT) stiffness was assessed before and after the NMES training by measuring the displacement of the MT junction and related tendon force during MVC. In a standing position, the limit of stability (LoS) performance was determined through the maximal forward displacement of the center of foot pressure, and related postural sway parameters were computed around the LoS time gap, a high force requiring task. The NMES training induced an increase in MVC, MT stiffness, and LoS. It significantly changed the dynamics of postural balance as a function of the tendon property changes. The study outcomes, together with a multivariate analysis of investigated variables, highlighted the benefits of NMES as a potential tool in combating neuromuscular weakening in the elderly. The presented training-based strategy is valuable in alleviating some of the adverse functional consequences of aging by directly acting on intrinsic biomechanical and muscular properties whose improvements are immediately transferable into a functional context.
authors.affiliation: Laboratory up-Courtine, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland Laboratory MIP (UPRES-EA4334), University of Nantes, Nantes, France mignardot.jb@gmail.com.
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Mignardot
authors.affiliation: Laboratory MIP (UPRES-EA4334), University of Nantes, Nantes, France.
authors.forename: Thibault
authors.initials: T
authors.lastname: Deschamps
authors.affiliation: Laboratory up-Courtine, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.
authors.forename: Camille G
authors.initials: CG
authors.lastname: Le Goff
authors.affiliation: Laboratory CASP (INSERM-U1093), University of Burgundy, Burgundy, France.
authors.forename: François-Xavier
authors.initials: FX
authors.lastname: Roumier
authors.affiliation: Laboratory CASP (INSERM-U1093), University of Burgundy, Burgundy, France Laboratory PRISSMH, team LAPMA (EA 4561), University of Tolouse III, Tolouse, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Duclay
authors.affiliation: Laboratory CASP (INSERM-U1093), University of Burgundy, Burgundy, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Martin
authors.affiliation: Geriatric Department, Hospital of Beaune (Burgundy), Beaune, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Sixt
authors.affiliation: Laboratory CASP (INSERM-U1093), University of Burgundy, Burgundy, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Pousson
authors.affiliation: Laboratory MIP (UPRES-EA4334), University of Nantes, Nantes, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Cornu
keywords: Muscle‐tendon unit; neuromuscular electrical stimulation; postural balance