title: Plantarflexor weakness is a determinant of kinetic asymmetry during gait in post-stroke individuals walking with high levels of effort.
abstract: BACKGROUND
  Some studies in post-stroke individuals hypothesized that asymmetrical gait might be a strategy to symmetrize the effort in lower limb muscles. This study analyzed the asymmetry in the levels of effort, net joint moment during gait (walking moment) and maximal potential moment in the plantarflexors, hip flexors and extensors during gait.
  
  
  METHODS
  Twenty post-stroke and 10 healthy individuals were assessed when walking at a comfortable speed on a treadmill. Their efforts were estimated bilaterally with a biomechanical approach (muscular utilization ratio) which is the walking moment relative to the muscle's maximal capability (maximal potential moment). Pearson correlations were used to assess the relationship between asymmetry in walking moment and maximal potential moment.
  
  
  RESULTS
  Healthy individuals presented symmetrical values of effort, walking moment and maximal potential moment for all muscle groups. Post-stroke individuals had asymmetrical walking moment in plantarflexion and hip extension. For the asymmetry in the levels of effort and maximal potential moment, they formed two subgroups; the low-effort subgroup presented symmetrical effort and their asymmetry in walking moment was not related to their asymmetry in maximal potential moment for plantarflexors (R = 0.44; P > 0.05). The high-effort subgroup presented asymmetrical effort (paretic side higher) and their asymmetry in walking moments was significantly associated to their asymmetry in maximal potential moment for plantarflexors and hip extensors (0.73≤R≤0.82; P<0.05).
  
  
  CONCLUSIONS
  Asymmetry in muscular strength is a determinant of walking moment asymmetry when the level of effort is high. These results might guide the type of locomotor training.
authors.affiliation: Centre de recherche interdisciplinaire en réadaptation (CRIR) - Institut de réadaptation Gingras-Lindsay de Montréal (IRGLM) du CIUSSS Centre-Est-de-l'Ile-de-Montréal, 6300 avenue Darlington, Montréal, Québec, H3S 2J4, Canada; École de réadaptation, Université de Montréal, C.P. 6128, succursale Centre-Ville, Montréal, Québec, H3C 3J7, Canada. Electronic address: selena.lauziere@umontreal.ca.
authors.forename: Séléna
authors.initials: S
authors.lastname: Lauzière
authors.affiliation: Centre de recherche interdisciplinaire en réadaptation (CRIR) - Institut de réadaptation Gingras-Lindsay de Montréal (IRGLM) du CIUSSS Centre-Est-de-l'Ile-de-Montréal, 6300 avenue Darlington, Montréal, Québec, H3S 2J4, Canada; École de réadaptation, Université de Montréal, C.P. 6128, succursale Centre-Ville, Montréal, Québec, H3C 3J7, Canada. Electronic address: carole.mieville@umontreal.ca.
authors.forename: Carole
authors.initials: C
authors.lastname: Miéville
authors.affiliation: Centre de recherche interdisciplinaire en réadaptation (CRIR) - Institut de réadaptation Gingras-Lindsay de Montréal (IRGLM) du CIUSSS Centre-Est-de-l'Ile-de-Montréal, 6300 avenue Darlington, Montréal, Québec, H3S 2J4, Canada; École de réadaptation, Université de Montréal, C.P. 6128, succursale Centre-Ville, Montréal, Québec, H3C 3J7, Canada. Electronic address: martina.betschart@umontreal.ca.
authors.forename: Martina
authors.initials: M
authors.lastname: Betschart
authors.affiliation: Centre de recherche interdisciplinaire en réadaptation (CRIR) - Institut de réadaptation Gingras-Lindsay de Montréal (IRGLM) du CIUSSS Centre-Est-de-l'Ile-de-Montréal, 6300 avenue Darlington, Montréal, Québec, H3S 2J4, Canada; Centre de Recherche du Centre Hospitalier Universitaire de Montréal (CRCHUM), Québec, Canada; École de technologie supérieure, 1100 rue Notre-Dame Ouest, Montréal, Québec, H3C 1K3, Canada. Electronic address: rachid.aissaoui@etsmlt.ca.
authors.forename: Rachid
authors.initials: R
authors.lastname: Aissaoui
authors.affiliation: Centre de recherche interdisciplinaire en réadaptation (CRIR) - Institut de réadaptation Gingras-Lindsay de Montréal (IRGLM) du CIUSSS Centre-Est-de-l'Ile-de-Montréal, 6300 avenue Darlington, Montréal, Québec, H3S 2J4, Canada; École de réadaptation, Université de Montréal, C.P. 6128, succursale Centre-Ville, Montréal, Québec, H3C 3J7, Canada. Electronic address: sylvie.nadeau@umontreal.ca.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Nadeau
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D005080:Exercise Test; D005260:Female; D005684:Gait / Q000502:physiology*; D020233:Gait Disorders, Neurologic / Q000503:physiopathology*; D006801:Humans; D035002:Lower Extremity / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D018908:Muscle Weakness / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000503:physiopathology*; D020521:Stroke / Q000150:complications*; D016138:Walking / Q000502:physiology*
keywords: Gait; Muscular effort; Rehabilitation; Stroke; Symmetry