title: Age-related alterations in the activation of trunk and lower limb muscles during walking.
abstract: BACKGROUND
  Walking is a complex motor task that requires an integrated coordination of the trunk, lower limb, and upper limb movements. Previously, few studies have investigated the activation pattern of trunk muscles during walking. However, the mechanisms by how aging affects the recruitment of trunk muscles during walking remain unclear.
  
  
  OBJECTIVE
  The present study aimed to compare the activation of trunk and lower limb muscles during walking in younger and older women.
  
  
  METHODS
  Fifteen younger women between 18 and 30 yr and 19 older women between 60-82 yr walked on the treadmill at a self-selected speed, while 1-min surface electromyography (EMG) signals were recorded from the multifidus, internal oblique, gluteus maximus, rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius lateralis. EMG signals were processed and a linear envelope was calculated at an initial stance (50 ms after heel contact) and final stance (50 ms before toe-off).
  
  
  RESULTS
  Compared with younger women, older women had 52.32% lower activation of the internal oblique (p = 0.027) and 39.95% lower activation of the rectus femoris (p = 0.003) at initial stance.
  
  
  CONCLUSIONS
  Results of this study demonstrated that older women had lower activation of trunk and knee muscles during the initial stance, which may have resulted from weakness and balance impairments caused by aging.
authors.affiliation: Department of Physical Therapy and Occupational Therapy, São Paulo State University, Marília, Brazil.
authors.forename: Nise Ribeiro
authors.initials: NR
authors.lastname: Marques
authors.affiliation: Department of Physical Therapy, Uberlandia Federal University, Uberlandia, Brazil.
authors.forename: Camilla Zamfolini
authors.initials: CZ
authors.lastname: Hallal
authors.affiliation: Department of Physical Therapy and Occupational Therapy, São Paulo State University, Marília, Brazil.
authors.forename: Deborah Hebling
authors.initials: DH
authors.lastname: Spinoso
authors.affiliation: Department of Physical Education, São Paulo State University, Rio Claro, Brazil.
authors.forename: Luciano Fernandez
authors.initials: LF
authors.lastname: Crozara
authors.affiliation: Department of Physical Education, São Paulo State University, Rio Claro, Brazil.
authors.forename: Mary Hellen
authors.initials: MH
authors.lastname: Morcelli
authors.affiliation: Department of Physical Therapy, São Paulo State University, Presidente Prudente, Brazil.
authors.forename: Aline Harumi
authors.initials: AH
authors.lastname: Karuka
authors.affiliation: Department of Physical Therapy and Occupational Therapy, São Paulo State University, Marília, Brazil.
authors.forename: Marcelo Tavella
authors.initials: MT
authors.lastname: Navega
authors.affiliation: Department of Physical Education, São Paulo State University, Rio Claro, Brazil.
authors.forename: Mauro
authors.initials: M
authors.lastname: Gonçalves
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D004576:Electromyography; D005080:Exercise Test; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D007866:Leg / Q000502:physiology*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology; D011446:Prospective Studies; D060726:Torso / Q000502:physiology*; D016138:Walking / Q000502:physiology*; D055815:Young Adult
keywords: Aging; electromyography; gait; trunk stability